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Deng N, Soh KG, Abdullah B, Huang D, Sun H, Xiao W. Effects of physical training programs on female tennis players' performance: a systematic review and meta-analysis. Front Physiol 2023; 14:1234114. [PMID: 37664429 PMCID: PMC10470022 DOI: 10.3389/fphys.2023.1234114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Accepted: 08/09/2023] [Indexed: 09/05/2023] Open
Abstract
Background: Tennis is among the world's most popular and well-studied sports. Physical training has commonly been used as an intervention among athletes. However, a comprehensive review of the literature on the effects of physical training programs on female tennis players' performance is lacking. Therefore, this systematic review and meta-analysis aimed to determine the effects of physical training on performance outcomes in female tennis players. Methods: A comprehensive search was conducted on Web of Science, PubMed, SPORTDicus, Scopus, and CNKI from inception until July 2023 to select relevant articles from the accessible literature. Only controlled trials were included if they examined the effects of physical training on at least one measure of tennis-specific performance in female tennis players. The Cochrane RoB tool was employed to assess the risk of bias. The CERT scale was used to examine the quality of program information. The GRADE approach was adopted to evaluate the overall quality of the evidence. The Comprehensive Meta-Analysis software was used for the meta-analysis. Results: Nine studies were selected for the systematic review and seven for the meta-analysis, totaling 222 individuals. The study's exercise programs lasted 6-36 weeks, with training sessions ranging from 30 to 80 min, conducted one to five times per week. Muscle power (ES = 0.72; p = 0.003), muscle strength (ES = 0.65; p = 0.002), agility (ES = 0.69; p = 0.002), serve velocity (ES = 0.72; p = 0.013), and serve accuracy (ES = 1.14; p = 0.002) demonstrated significant improvement following physical training, while no notable changes in linear sprint speed (ES = 0.63; p = 0.07) were detected. Conclusion: Although research on physical training in sports is diversified, studies on training interventions among female tennis players are scarce. This review found that existing training programs yield some favorable outcomes for female tennis players. However, further research with high methodological quality is warranted on the tailoring of specific training programs for female tennis players. There should be more consistent measuring and reporting of data to facilitate meaningful data pooling for future meta-analyses.
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Affiliation(s)
- Nuannuan Deng
- Department of Sports Studies, Faculty of Educational Studies, Universiti Putra Malaysia, Selangor, Malaysia
| | - Kim Geok Soh
- Department of Sports Studies, Faculty of Educational Studies, Universiti Putra Malaysia, Selangor, Malaysia
| | - Borhannudin Abdullah
- Department of Sports Studies, Faculty of Educational Studies, Universiti Putra Malaysia, Selangor, Malaysia
| | - Dandan Huang
- College of Physical Education, Chongqing University, Chongqing, China
| | - He Sun
- School of Physical Education Institute (Main Campus), Zhengzhou University, Zhengzhou, China
| | - Wensheng Xiao
- Department of Sports Sciences, Huzhou University, Huzhou, China
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2
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Türker D, Yakut Y, Yaşar E, Kerem Günel M, Yılmaz B, Tan AK. The effects of functional electrical stimulation cycling on gait parameters in diplegic cerebral palsy: a single-blind randomized controlled trial. Somatosens Mot Res 2023; 40:62-71. [PMID: 36645809 DOI: 10.1080/08990220.2022.2157393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
PURPOSE To investigate the effects of functional electrical stimulation cycling (FES-C) training in addition to conventional physical therapy on gait, muscle strength, gross motor function, and energy expenditure in ambulatory children with spastic diplegic cerebral palsy. MATERIALS AND METHODS Twenty children with diplegic cerebral palsy were randomly assigned to FES-C group (n = 10) or control group (n = 10). Subjects trained 3 days/week for 8 weeks. Control group received conventional physical therapy. The FES-C group additionally received FES-C training. The functional muscle test was used for muscle strength assessment. Vicon-3D system was used for gait analysis. Gross Motor Function Measure (GMFM-88) was used for motor function assessment and calorimeter was used for energy expenditure. Measurements were performed at the baseline, at the eight week and at the sixteenth week. RESULTS Functional muscle strength, gross motor function, and energy expenditure improved more in the FES-C group after training and follow up (p < 0.05). There was no significant difference found between the changes in gait parameters of the two groups after treatment and follow up (p > 0.05). Pelvic tilt while walking decreased after training in the FES-C group (p < 0.05). CONCLUSIONS FES-C applied in addition to conventional physical therapy in children with diplegic cerebral palsy is more effective than conventional physical therapy for increasing functional muscle strength, improving gross motor function functions, and reducing energy expenditure.HighlightsFES-C improves lower extremity functional muscle strength, gross motor function, and energy expenditure in ambulatory children with spastic dCP.The use of FES-C in combination with conventional physiotherapy methods may be beneficial in outpatients with spastic dCP.
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Affiliation(s)
- Duygu Türker
- Faculty of Gülhane Physiotherapy and Rehabilitation, Department of Pediatric Rehabilitation, University of Health Sciences, Ankara, Turkey
| | - Yavuz Yakut
- Faculty of Health Sciences, Department of Physiotherapy and Rehabilitation, Hasan Kalyoncu University, Gaziantep, Turkey
| | - Evren Yaşar
- Department of Physical Medicine and Rehabilitation, Gulhane School of Medicine, University of Health Sciences, Ankara City Hospital, Physical Therapy and Rehabilitation Hospital, Ankara, Turkey
| | - Mintaze Kerem Günel
- Faculty of Physical Therapy Rehabilitation, Hacettepe University, Ankara, Turkey
| | - Bilge Yılmaz
- Department of Physical Medicine and Rehabilitation, Gulhane School of Medicine, University of Health Sciences, Ankara City Hospital, Physical Therapy and Rehabilitation Hospital, Ankara, Turkey.,Department of Physical Medicine and Rehabilitation, Gulhane School of Medicine, University of Health Sciences, Gaziler Training and Research Hospital, Ankara, Turkey.,Department of Physical Medicine and Rehabilitation, Gulhane School of Medicine, University of Health Sciences, Gaziler Training and Research Hospital
| | - Arif Kenan Tan
- Department of Physical Medicine and Rehabilitation, Gulhane School of Medicine, University of Health Sciences, Ankara City Hospital, Physical Therapy and Rehabilitation Hospital, Ankara, Turkey.,Department of Physical Medicine and Rehabilitation, Gulhane School of Medicine, University of Health Sciences, Gaziler Training and Research Hospital, Ankara, Turkey.,Department of Physical Medicine and Rehabilitation, Gulhane School of Medicine, University of Health Sciences, Gaziler Training and Research Hospital
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3
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Hering GO, Bertschinger R, Stepan J. A quadriceps femoris motor pattern for efficient cycling. PLoS One 2023; 18:e0282391. [PMID: 36928839 PMCID: PMC10019633 DOI: 10.1371/journal.pone.0282391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 02/13/2023] [Indexed: 03/18/2023] Open
Abstract
In cycling, propulsion is generated by the muscles of the lower limbs and hips. After the first reports of pedal/crank force measurements in the late 1960s, it has been assumed that highly trained athletes have better power transfer to the pedals than recreational cyclists. However, motor patterns indicating higher levels of performance are unknown. To compare leg muscle activation between trained (3.5-4.2 W/kgbw) and highly trained (4.3-5.1 W/kgbw) athletes we applied electromyography, lactate, and bi-pedal/crank force measurements during a maximal power test, an individual lactate threshold test and a constant power test. We show that specific activation patterns of the rectus femoris (RF) and vastus lateralis (VL) impact on individual performance during high-intensity cycling. In highly trained cyclists, we found a strong activation of the RF during hip flexion. This results in reduced negative force in the fourth quadrant of the pedal cycle. Furthermore, we discovered that pre-activation of the RF during hip flexion reduces force loss at the top dead center (TDC) and can improve force development during subsequent leg extension. Finally, we found that a higher performance level is associated with earlier and more intense coactivation of the RF and VL. This quadriceps femoris recruitment pattern improves force transmission and maintains propulsion at the TDC of the pedal cycle. Our results demonstrate neuromuscular adaptations in cycling that can be utilized to optimize training interventions in sports and rehabilitation.
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Affiliation(s)
- Gernot O. Hering
- Department of Sport and Health Science, University of Konstanz, Konstanz, Germany
- * E-mail:
| | - Raphael Bertschinger
- Department of Sport and Health Science, University of Konstanz, Konstanz, Germany
| | - Jens Stepan
- Department of Sport and Health Science, University of Konstanz, Konstanz, Germany
- Department of Obstetrics and Gynecology, Paracelsus Medical University, Salzburg, Austria
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4
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Handheld-Load-Specific Jump Training over 8 Weeks Improves Standing Broad Jump Performance in Adolescent Athletes. Healthcare (Basel) 2022; 10:healthcare10112301. [DOI: 10.3390/healthcare10112301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/10/2022] [Accepted: 11/16/2022] [Indexed: 11/19/2022] Open
Abstract
This study investigated the effects of handheld-load-specific jump training on standing broad jump (SBJ) performance in youth athletes and the biomechanics changes involved. Methods: Fifteen male athletes (mean age, body weight, height, and body mass index were 14.7 ± 0.9 years, 59.3 ± 8.0 kg, 1.73 ± 0.07 m, 19.8 ± 2, respectively) underwent 15 SBJ training sessions over 8 weeks. The data were collected over three phases: before training, after training, and after training with 4 kg loading. Ten infrared high-speed motion-capture cameras and two force platforms, whose sampling rates were 250 and 1000 Hz, respectively, were used to record the kinematic and kinetic data. Visual three-dimensional software was used for the data analyses. Results: Jump performance and all biomechanics variables, including joint and takeoff velocities, ground reaction force, takeoff impulse, and mechanical outputs, improved after training. Conclusions: SBJ training under handheld loading resulted in considerable acute improvements as well as training transfer after 8 weeks. Moreover, explosive ability was effectively enhanced. The present findings serve as a reference for SBJ assessment and jump-related training.
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5
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Effect of Heel Lift Insoles on Lower Extremity Muscle Activation and Joint Work during Barbell Squats. Bioengineering (Basel) 2022; 9:bioengineering9070301. [PMID: 35877352 PMCID: PMC9312299 DOI: 10.3390/bioengineering9070301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/05/2022] [Accepted: 07/05/2022] [Indexed: 11/17/2022] Open
Abstract
The effect of heel elevation on the barbell squat remains controversial, and further exploration of muscle activity might help find additional evidence. Therefore, 20 healthy adult participants (10 males and 10 females) were recruited for this study to analyze the effects of heel height on lower extremity kinematics, kinetics, and muscle activity using the OpenSim individualized musculoskeletal model. One-way repeated measures ANOVA was used for statistical analysis. The results showed that when the heel was raised, the participant’s ankle dorsiflexion angle significantly decreased, and the percentage of ankle work was increased (p < 0.05). In addition, there was a significant increase in activation of the vastus lateralis, biceps femoris, and gastrocnemius muscles and a decrease in muscle activation of the anterior tibialis muscle (p < 0.05). An increase in knee moments and work done and a reduction in hip work were observed in male subjects (p < 0.05). In conclusion, heel raises affect lower extremity kinematics and kinetics during the barbell squat and alter the distribution of muscle activation and biomechanical loading of the joints in the lower extremity of participants to some extent, and there were gender differences in the results.
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6
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Proud JK, Lai DTH, Mudie KL, Carstairs GL, Billing DC, Garofolini A, Begg RK. Exoskeleton Application to Military Manual Handling Tasks. HUMAN FACTORS 2022; 64:527-554. [PMID: 33203237 DOI: 10.1177/0018720820957467] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
OBJECTIVE The aim of this review was to determine how exoskeletons could assist Australian Defence Force personnel with manual handling tasks. BACKGROUND Musculoskeletal injuries due to manual handling are physically damaging to personnel and financially costly to the Australian Defence Force. Exoskeletons may minimize injury risk by supporting, augmenting, and/or amplifying the user's physical abilities. Exoskeletons are therefore of interest in determining how they could support the unique needs of military manual handling personnel. METHOD Industrial and military exoskeleton studies from 1990 to 2019 were identified in the literature. This included 67 unique exoskeletons, for which Information about their current state of development was tabulated. RESULTS Exoskeleton support of manual handling tasks is largely through squat/deadlift (lower limb) systems (64%), with the proposed use case for these being load carrying (42%) and 78% of exoskeletons being active. Human-exoskeleton analysis was the most prevalent form of evaluation (68%) with reported reductions in back muscle activation of 15%-54%. CONCLUSION The high frequency of citations of exoskeletons targeting load carrying reflects the need for devices that can support manual handling workers. Exoskeleton evaluation procedures varied across studies making comparisons difficult. The unique considerations for military applications, such as heavy external loads and load asymmetry, suggest that a significant adaptation to current technology or customized military-specific devices would be required for the introduction of exoskeletons into a military setting. APPLICATION Exoskeletons in the literature and their potential to be adapted for application to military manual handling tasks are presented.
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Affiliation(s)
| | | | - Kurt L Mudie
- 2222 Defence Science and Technology (DST), Melbourne, Australia
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7
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Acute Effects of Handheld Loading on Standing Broad Jump in Youth Athletes. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18095046. [PMID: 34068833 PMCID: PMC8126242 DOI: 10.3390/ijerph18095046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 04/28/2021] [Accepted: 04/28/2021] [Indexed: 12/02/2022]
Abstract
The study aimed to investigate the acute effects of handheld loading on standing broad jump (SBJ) performance and biomechanics. Fifteen youth male athletes (mean age: 14.7 ± 0.9 years; body mass: 59.3 ± 8.0 kg; height: 1.73 ± 0.07 m) volunteered to participate in the study. Participants were assigned to perform SBJ with and without 4 kg dumbbells in a random order. Kinematic and kinetic data were collected using 10 infrared high-speed motion-capture cameras at a 250 Hz sampling rate and two force platforms at a 1000 Hz sampling rate. A paired t-test was applied to all variables to determine the significance between loading and unloading SBJs. Horizontal distance (p < 0.001), take-off distance (p = 0.001), landing distance (p < 0.001), horizontal velocity of center of mass (CoM; p < 0.001), push time (p < 0.001), vertical impulse (p = 0.003), and peak horizontal and vertical ground reaction force (GRF; p < 0.001, p = 0.017) were significantly greater in loading SBJ than in unloading SBJ. The take-off vertical velocity of CoM (p = 0.001), take-off angle (p < 0.001), peak knee and hip velocity (p < 0.001, p = 0.007), peak ankle and hip moment (p = 0.006, p = 0.011), and peak hip power (p = 0.014) were significantly greater in unloading SBJ than in loading SBJ. Conclusions: Acute enhancement in SBJ performance was observed with handheld loading. The present findings contribute to the understanding of biomechanical differences in SBJ performance with handheld loading and are highly applicable to strength and conditioning training for athletes.
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8
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Jo H, Choi W, Lee G, Park W, Kim J. Analysis of Visuo Motor Control between Dominant Hand and Non-Dominant Hand for Effective Human-Robot Collaboration. SENSORS 2020; 20:s20216368. [PMID: 33171652 PMCID: PMC7664673 DOI: 10.3390/s20216368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 11/16/2022]
Abstract
The human-in-the-loop technology requires studies on sensory-motor characteristics of each hand for an effective human-robot collaboration. This study aims to investigate the differences in visuomotor control between the dominant (DH) and non-dominant hands in tracking a target in the three-dimensional space. We compared the circular tracking performances of the hands on the frontal plane of the virtual reality space in terms of radial position error (ΔR), phase error (Δθ), acceleration error (Δa), and dimensionless squared jerk (DSJ) at four different speeds for 30 subjects. ΔR and Δθ significantly differed at relatively high speeds (ΔR: 0.5 Hz; Δθ: 0.5, 0.75 Hz), with maximum values of ≤1% compared to the target trajectory radius. DSJ significantly differed only at low speeds (0.125, 0.25 Hz), whereas Δa significantly differed at all speeds. In summary, the feedback-control mechanism of the DH has a wider range of speed control capability and is efficient according to an energy saving model. The central nervous system (CNS) uses different models for the two hands, which react dissimilarly. Despite the precise control of the DH, both hands exhibited dependences on limb kinematic properties at high speeds (0.75 Hz). Thus, the CNS uses a different strategy according to the model for optimal results.
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Affiliation(s)
- Hanjin Jo
- Department of Mechanical and Control Engineering, Handong Global University, Pohang 37554, Korea; (H.J.); (G.L.); (W.P.)
| | - Woong Choi
- Department of Information and Computer Engineering, National Institute of Technology, Gunma College, Maebashi 371–8530, Japan
- Correspondence: (W.C.); (J.K.)
| | - Geonhui Lee
- Department of Mechanical and Control Engineering, Handong Global University, Pohang 37554, Korea; (H.J.); (G.L.); (W.P.)
| | - Wookhyun Park
- Department of Mechanical and Control Engineering, Handong Global University, Pohang 37554, Korea; (H.J.); (G.L.); (W.P.)
| | - Jaehyo Kim
- Department of Mechanical and Control Engineering, Handong Global University, Pohang 37554, Korea; (H.J.); (G.L.); (W.P.)
- Correspondence: (W.C.); (J.K.)
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9
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Chaytor CP, Forman D, Byrne J, Loucks-Atkinson A, Power KE. Changes in muscle activity during the flexion and extension phases of arm cycling as an effect of power output are muscle-specific. PeerJ 2020; 8:e9759. [PMID: 32983635 PMCID: PMC7500348 DOI: 10.7717/peerj.9759] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/28/2020] [Indexed: 01/08/2023] Open
Abstract
Arm cycling is commonly used in rehabilitation settings for individuals with motor impairments in an attempt to facilitate neural plasticity, potentially leading to enhanced motor function in the affected limb(s). Studies examining the neural control of arm cycling, however, typically cycle using a set cadence and power output. Given the importance of motor output intensity, typically represented by the amplitude of electromyographic (EMG) activity, on neural excitability, surprisingly little is known about how arm muscle activity is modulated using relative workloads. Thus, the objective of this study was to characterize arm muscle activity during arm cycling at different relative workloads. Participants (n = 11) first completed a 10-second maximal arm ergometry sprint to determine peak power output (PPO) followed by 11 randomized trials of 20-second arm cycling bouts ranging from 5–50% of PPO (5% increments) and a standard 25 W workload. All submaximal trials were completed at 60 rpm. Integrated EMG amplitude (iEMG) was assessed from the biceps brachii, brachioradialis, triceps brachii, flexor carpi radialis, extensor carpi radialis and anterior deltoid of the dominant arm. Arm cycling was separated into two phases, flexion and extension, relative to the elbow joint for all comparisons. As expected, iEMG amplitude increased during both phases of cycling for all muscles examined. With the exception of the triceps brachii and extensor carpi radialis, iEMG amplitudes differed between the flexion and extension phases. Finally, there was a linear relationship between iEMG amplitude and the %PPO for all muscles during both elbow flexion and extension.
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Affiliation(s)
- Carla P Chaytor
- Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Davis Forman
- Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Jeannette Byrne
- Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Angela Loucks-Atkinson
- Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Kevin E Power
- Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
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Burnie L, Barratt P, Davids K, Worsfold P, Wheat J. Biomechanical measures of short-term maximal cycling on an ergometer: a test-retest study. Sports Biomech 2020:1-19. [PMID: 32781910 DOI: 10.1080/14763141.2020.1773916] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
An understanding of test-retest reliability is important for biomechanists, such as when assessing the longitudinal effect of training or equipment interventions. Our aim was to quantify the test-retest reliability of biomechanical variables measured during short-term maximal cycling. Fourteen track sprint cyclists performed 3 × 4 s seated sprints at 135 rpm on an isokinetic ergometer, repeating the session 7.6 ± 2.5 days later. Joint moments were calculated via inverse dynamics, using pedal forces and limb kinematics. EMG activity was measured for 9 lower limb muscles. Reliability was explored by quantifying systematic and random differences within- and between-session. Within-session reliability was better than between-sessions reliability. The test-retest reliability level was typically moderate to excellent for the biomechanical variables that describe maximal cycling. However, some variables, such as peak knee flexion moment and maximum hip joint power, demonstrated lower reliability, indicating that care needs to be taken when using these variables to evaluate biomechanical changes. Although measurement error (instrumentation error, anatomical marker misplacement, soft tissue artefacts) can explain some of our reliability observations, we speculate that biological variability may also be a contributor to the lower repeatability observed in several variables including ineffective crank force, ankle kinematics and hamstring muscles' activation patterns.
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Affiliation(s)
- Louise Burnie
- Applied Sports, Technology, Exercise and Medicine Research Centre, Swansea University, Swansea, UK.,Sport and Physical Activity Research Centre, Sheffield Hallam University, Sheffield, UK.,Biomechanics, English Institute of Sport, Manchester, UK
| | | | - Keith Davids
- Sport and Physical Activity Research Centre, Sheffield Hallam University, Sheffield, UK
| | - Paul Worsfold
- Biomechanics, English Institute of Sport, Manchester, UK.,Sport and Exercise Sciences, University of Chester, Chester, UK
| | - Jon Wheat
- College of Health, Wellbeing and Life Sciences, Sheffield Hallam University, Sheffield, UK
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11
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Analysis of Control Characteristics between Dominant and Non-Dominant Hands by Transient Responses of Circular Tracking Movements in 3D Virtual Reality Space. SENSORS 2020; 20:s20123477. [PMID: 32575627 PMCID: PMC7348742 DOI: 10.3390/s20123477] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 12/05/2022]
Abstract
Human movement is a controlled result of the sensory-motor system, and the motor control mechanism has been studied through diverse movements. The present study examined control characteristics of dominant and non-dominant hands by analyzing the transient responses of circular tracking movements in 3D virtual reality space. A visual target rotated in a circular trajectory at four different speeds, and 29 participants tracked the target with their hands. The position of each subject’s hand was measured, and the following three parameters were investigated: normalized initial peak velocity (IPV2), initial peak time (IPT2), and time delay (TD2). The IPV2 of both hands decreased as target speed increased. The results of IPT2 revealed that the dominant hand reached its peak velocity 0.0423 s earlier than the non-dominant hand, regardless of target speed. The TD2 of the hands diminished by 0.0218 s on average as target speed increased, but the dominant hand statistically revealed a 0.0417-s shorter TD2 than the non-dominant hand. Velocity-control performances from the IPV2 and IPT2 suggested that an identical internal model controls movement in both hands, whereas the dominant hand is likely more experienced than the non-dominant hand in reacting to neural commands, resulting in better reactivity in the movement task.
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13
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Loh PY, Hayashi K, Nasir N, Muraki S. Changes in Muscle Activity in Response to Assistive Force during Isometric Elbow Flexion. J Mot Behav 2019; 52:634-642. [PMID: 31571525 DOI: 10.1080/00222895.2019.1670128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
This study investigated the muscle activity and force variability in response to perturbation of assistive force during isometric elbow flexion. Sixteen healthy right-handed young men (age: 22.0 ± 1.1 years; height: 171.9 ± 4.8 cm; weight 68.4 ± 11.2 kg) were recruited and the muscle activity of biceps brachii and triceps brachii were assessed using surface electromyography. Workload force and assistive force applied on isometric elbow flexion significantly affected the changes in both biceps and triceps muscle activities. A higher assistive force was shown to result in reduced biceps muscle activity compared to the unassisted period. In contrast, the efficiency of the assistive force acting on the biceps decreased as the assistive force increased. In general, the force variability of the biceps muscle remained approximately the same at lower workload force conditions than that at higher workload force conditions. In conclusion, higher assistive force may not yield a higher performance efficiency in human-assistive force interaction.
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Affiliation(s)
- Ping Yeap Loh
- Department of Human Science, Faculty of Design, Kyushu University, Fukuoka, Japan
| | - Keisuke Hayashi
- Department of Human Science, Graduate School of Design, Kyushu University, Fukuoka, Japan
| | - Nursalbiah Nasir
- Department of Human Science, Graduate School of Design, Kyushu University, Fukuoka, Japan.,Faculty of Mechanical Engineering, Universiti Teknologi Mara, Shah Alam, Malaysia
| | - Satoshi Muraki
- Department of Human Science, Faculty of Design, Kyushu University, Fukuoka, Japan
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Comparison of Peak Ground Reaction Force, Joint Kinetics and Kinematics, and Muscle Activity Between a Flexible and Steel Barbell During the Back Squat Exercise. J Hum Kinet 2019; 68:99-108. [PMID: 31531136 PMCID: PMC6724600 DOI: 10.2478/hukin-2019-0059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The flexible barbell is purported to improve training gains compared with an Olympic steel barbell (SB) during the back squat exercise with Division I collegiate American football programs. The two bars loaded at 30% 1-repetition maximum were compared with ten trained Division I American football players (n = 10; age = 19.5 years; body mass = 89.4 kg; body height = 182.0 cm) completing 10 repetitions of the back squat exercise. Analysis included integrated-peak values of electromyography of the rectus femoris, biceps femoris, rectus abdominis, erector spinae, external oblique, vastus lateralis, ground reaction forces, and joint kinematics and kinetics of the hip, knee, and ankle. The flexible bar elicited significant increases in peak joint kinetics (Hip Moment: 229 ± 54 Nm vs. 209 ± 52 Nm; Hip Power: 494 ± 151 W vs. 382 ± 134 W; Knee Power: 305 ± 108 W vs. 241 ± 63 W), peak vertical ground reaction forces (1195 ± 209 N vs. 1120 ± 203 N), and muscle activity (Vastus Lateralis: 75.7 vs. 66.5%, Rectus Abdominis: 190 vs. 115%, Rectus Femoris: 69.8 vs. 59.9%, External Oblique: 115 vs. 69.0%). Greater vertical ground reaction forces, hip moment, hip power, knee power, and muscle activity of the vastus lateralis, rectus abdominis, rectus femoris, and external oblique suggest the FB provides biomechanical and physiological mechanisms for training gains over the SB for 30% of 1-repetition maximum loads.
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Wakeling JM, Hodson-Tole EF. How Do the Mechanical Demands of Cycling Affect the Information Content of the EMG? Med Sci Sports Exerc 2019; 50:2518-2525. [PMID: 29975298 DOI: 10.1249/mss.0000000000001713] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE The persistence of phase-related information in EMG signals can be quantified by its entropic half-life (EnHL). It has been proposed that the EnHL would increase with the demands of a movement task, and thus increase as the pedaling power increased during cycling. However, simulation work on the properties of EMG signals suggests that the EnHL depends on burst duration and duty cycle in the EMG that may not be related to task demands. This study aimed to distinguish between these alternate hypotheses. METHODS The EnHL was characterized for 10 muscles from nine cyclists cycling at a range of powers (35 to 260 W) and cadences (60-140 rpm) for the raw EMG, phase-randomized surrogate EMG, EMG intensity, and the principal components describing the muscle coordination patterns. RESULTS There was phase-related information in the raw EMG signals and EMG intensities that was related to the EMG burst duration, duty cycle pedaling cadence, and power. The EnHL for the EMG intensities of the individual muscles (excluding quadriceps) and for the coordination patterns decreased as cycling power and cadence increased. CONCLUSIONS The EnHL provide information on the structure of the motor control signals and their constituent motor unit action potentials, both within and between muscles, rather than on the mechanical demands of the cycling task per se.
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Affiliation(s)
- James M Wakeling
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, CANADA
| | - Emma F Hodson-Tole
- School of Healthcare Science, Manchester Metropolitan University, Manchester, UNITED KINGDOM
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A Randomized Clinical Trial of a Functional Electrical Stimulation Mimic to Gait Promotes Motor Recovery and Brain Remodeling in Acute Stroke. Behav Neurol 2018; 2018:8923520. [PMID: 30662575 PMCID: PMC6312612 DOI: 10.1155/2018/8923520] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 10/22/2018] [Indexed: 11/20/2022] Open
Abstract
Functional electrical stimulation can improve motor function after stroke. The mechanism may involve activity-dependent plasticity and brain remodeling. The aim of our study was to investigate the effectiveness of a patterned electrical stimulation FES mimic to gait in motor recovery among stroke survivors and to investigate possible mechanisms through brain fMRI. Forty-eight subjects were recruited and randomly assigned to a four-channel FES group (n = 18), a placebo group (n = 15), or a dual-channel FES group (n = 15). Stimulation lasted for 30 minutes in each session for 3 weeks. All of the subjects were assessed at baseline and after weeks 1, 2, and 3. The assessments included the Fugl-Meyer Assessment, the Postural Assessment Scale for Stroke Patients, Brunel's Balance Assessment, the Berg Balance Scale, and the modified Barthel Index. Brain fMRI were acquired before and after the intervention. All of the motor assessment scores significantly increased week by week in all the three groups. The four-channel group showed significantly better improvement than the dual-channel group and placebo groups. fMRI showed that fractional anisotropy was significantly increased in both the four-channel and dual-channel groups compared with the placebo group and fiber bundles had increased significantly on the ipsilateral side, but not on the contralateral side in the group given four-channel stimulation. In conclusion, when four-channel FES induces cycling movement of the lower extremities based on a gait pattern, it may be more effective in promoting motor recovery and induce more plastic changes and brain remodeling than two-channel stimulation. This trial is registered with clinical trial registration unique identifier ChiCTR-TRC-11001615.
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Williams KJ, Chapman DW, Phillips EJ, Ball N. Effects of Athlete-Dependent Traits on Joint and System Countermovement-Jump Power. Int J Sports Physiol Perform 2018; 13:1378-1385. [PMID: 29809056 DOI: 10.1123/ijspp.2018-0050] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 04/09/2018] [Accepted: 05/08/2018] [Indexed: 11/18/2022]
Abstract
PURPOSE To establish the influence of athlete-dependent characteristics on the generation and timing of system and individual joint powers during a countermovement jump (CMJ). METHODS Male national representative athletes from volleyball (n = 7), basketball (n = 6), and rugby (n = 7) performed a set of 3 CMJs at relative barbell loads of 0%, 10%, 20%, 30%, and 40% of absolute back-squat strength. Ground-reaction forces and joint kinematics were captured using a 16-camera motion-capture system integrated with 2 in-ground force plates. Limb lengths and cross-sectional areas were defined using 3-dimensional photonic scans. A repeated-measures analysis of variance determined the interaction between system and joint load-power profiles, whereas a multiregression analysis defined the explained variance of athlete-dependent characteristics on the load that maximized system power. RESULTS System and isolated hip, knee, and ankle peak powers were maximized across a spectrum of loads between and within sports; power values were not significantly different across loads. A positive shift in the timing of hip and ankle peak powers corresponded to a significant (P < .05) positive shift in the timing of system peak power to occur closer to toe-off. An optimal 3-input combination of athlete-dependent characteristics accounted for 68% (P < .001) of the explained variance in the load that maximized system peak power. CONCLUSION The load maximizing system power is athlete-dependent, with a mixture of training and heredity-related characteristics influencing CMJ load-power profiles. The authors recommend that a combination of relative loads be individually prescribed to maximize the generation and translation of system CMJ power.
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Ries AJ, Schwartz MH. Low gait efficiency is the primary reason for the increased metabolic demand during gait in children with cerebral palsy. Hum Mov Sci 2018; 57:426-433. [DOI: 10.1016/j.humov.2017.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 10/05/2017] [Accepted: 10/12/2017] [Indexed: 10/18/2022]
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19
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Functional significance of extent and timing of muscle activation during double poling on-snow with increasing speed. Eur J Appl Physiol 2017; 117:2149-2157. [DOI: 10.1007/s00421-017-3703-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 08/11/2017] [Indexed: 10/19/2022]
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Carmona-Duarte C, de Torres-Peralta R, Diaz M, Ferrer MA, Martin-Rincon M. Myoelectronic signal-based methodology for the analysis of handwritten signatures. Hum Mov Sci 2017; 55:18-30. [PMID: 28750258 DOI: 10.1016/j.humov.2017.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 05/10/2017] [Accepted: 07/16/2017] [Indexed: 12/23/2022]
Abstract
With the overall aim of improving the synthesis of handwritten signatures, we have studied how muscle activation depends on handwriting style for both text and flourish. Surface electromyographic (EMG) signals from a set of twelve arm and trunk muscles were recorded in synchronization with handwriting produced on a digital Tablet. Correlations between these EMG signals and handwritten trajectory signals were analyzed so as to define the sequence of muscles activated during the different parts of the signature. Our results establish a correlation between the speed of the movement, stroke size, handwriting style and muscle activation. Muscle activity appeared to be clustered as a function of movement speed and handwriting style, a finding which may be used for filter design in a signature synthesizer.
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Affiliation(s)
- Cristina Carmona-Duarte
- Instituto Universitario para el Desarrollo Tecnológico y la Innovación en Comunicaciones, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain.
| | - Rafael de Torres-Peralta
- Department of Physical Education, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain.
| | - Moises Diaz
- Instituto Universitario para el Desarrollo Tecnológico y la Innovación en Comunicaciones, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain.
| | - Miguel A Ferrer
- Instituto Universitario para el Desarrollo Tecnológico y la Innovación en Comunicaciones, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain.
| | - Marcos Martin-Rincon
- Department of Physical Education, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain.
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Steele KM, Shuman BR, Schwartz MH. Crouch severity is a poor predictor of elevated oxygen consumption in cerebral palsy. J Biomech 2017; 60:170-174. [PMID: 28734543 DOI: 10.1016/j.jbiomech.2017.06.036] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 06/16/2017] [Accepted: 06/20/2017] [Indexed: 11/25/2022]
Abstract
Children with cerebral palsy (CP) expend more energy to walk compared to typically-developing peers. One of the most prevalent gait patterns among children with CP, crouch gait, is often singled out as especially exhausting. The dynamics of crouch gait increase external flexion moments and the demand on extensor muscles. This elevated demand is thought to dramatically increase energy expenditure. However, the impact of crouch severity on energy expenditure has not been investigated among children with CP. We evaluated oxygen consumption and gait kinematics for 573 children with bilateral CP. The average net nondimensional oxygen consumption during gait of the children with CP (0.18±0.06) was 2.9 times that of speed-matched typically-developing peers. Crouch severity was only modestly related to oxygen consumption, with measures of knee flexion angle during gait explaining only 5-20% of the variability in oxygen consumption. While knee moment and muscle activity were moderately to strongly correlated with crouch severity (r2=0.13-0.73), these variables were only weakly correlated with oxygen consumption (r2=0.02-0.04). Thus, although the dynamics of crouch gait increased muscle demand, these effects did not directly result in elevated energy expenditure. In clinical gait analysis, assumptions about an individual's energy expenditure should not be based upon kinematics or kinetics alone. Identifying patient-specific factors that contribute to increased energy expenditure may provide new pathways to improve gait for children with CP.
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Affiliation(s)
- Katherine M Steele
- Mechanical Engineering, University of Washington, Seattle, WA, United States.
| | - Benjamin R Shuman
- Mechanical Engineering, University of Washington, Seattle, WA, United States
| | - Michael H Schwartz
- James R. Gage Center for Gait & Motion Analysis, Gillette Children's Specialty Healthcare, St. Paul, MN, United States; Orthopaedic Surgery, University of Minnesota, Minneapolis, MN, United States
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Can muscle coordination explain the advantage of using the standing position during intense cycling? J Sci Med Sport 2016; 20:611-616. [PMID: 27889272 DOI: 10.1016/j.jsams.2016.10.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 10/21/2016] [Accepted: 10/22/2016] [Indexed: 01/08/2023]
Abstract
OBJECTIVES When compared to seated, the standing position allows the production of higher power outputs during intense cycling. We hypothesized that muscle coordination could explain this advantage. To test this hypothesis, we assessed muscle activity over a wide range of power outputs for both seated and standing cycling positions. DESIGN Nine lower limb muscle activities from seventeen untrained volunteers were recorded during cycling sequences performed in the seated and the standing positions at power outputs ranging from ∼100 to 700W at 90±5 revolutions-per-minute (RPM). METHODS Integrated electromyography activity (iEMG), temporal patterns of the EMGs, and muscle synergies were analyzed. RESULTS Muscle activity was underlain by four muscle synergies in both positions. Muscle synergies were similar in the two positions (Pearson's r=0.929±0.125). The activation patterns of knee and ankle extensor muscles and their associated synergies had different timings in the two positions (differences of ∼2-10% of cycle). No major timing changes were observed with power output (<2% of cycle). Differences in iEMG between the two positions depended strongly on power output in all but the calf muscle (medial gastrocnemius). CONCLUSIONS The number and structure of the muscle synergies play a minor role in the advantage of using the standing position when cycling at high power-outputs. However, the standing position is favorable in terms of iEMG at power outputs ≳500-600W due to position-dependent modulations of muscle activation levels. These data are important for understanding the determinants of the seat-stand transition in cycling.
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Dick TJM, Arnold AS, Wakeling JM. Quantifying Achilles tendon force in vivo from ultrasound images. J Biomech 2016; 49:3200-3207. [PMID: 27544621 DOI: 10.1016/j.jbiomech.2016.07.036] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 07/25/2016] [Accepted: 07/28/2016] [Indexed: 11/19/2022]
Abstract
This study evaluated a procedure for estimating in vivo Achilles tendon (AT) force from ultrasound images. Two aspects of the procedure were tested: (i) accounting for subject-specific AT stiffness and (ii) accounting for changes in the relative electromyographic (EMG) intensities of the three triceps surae muscles. Ten cyclists pedaled at 80rpm while a comprehensive set of kinematic, kinetic, EMG, and ultrasound data were collected. Subjects were tested at four crank loads, ranging from 14 to 44Nm (115 to 370W). AT forces during cycling were estimated from AT length changes and from AT stiffness, which we derived for each subject from ultrasound data and from plantar flexion torques measured during isometric tests. AT length changes were measured by tracking the muscle-tendon junction of the medial gastrocnemius (MG) relative to its insertion on the calcaneus. Because the relative EMG intensities of the triceps surae muscles varied with load during cycling, we divided subjects׳ measured AT length changes by a scale factor, defined as the square root of the relative EMG intensity of the MG, weighted by the fractional physiological cross-sectional areas of the three muscles, to estimate force. Subjects׳ estimated AT forces during cycling increased with load (p<0.05). On average, peak forces ranged from 920±96N (14Nm, 115W) to 1510±129N (44Nm, 370W). For most subjects, ankle moments derived from the ultrasound-based AT strains were 5-12% less than the net ankle moments calculated from inverse dynamics (r2=0.71±0.28, RMSE=8.1±0.33Nm). Differences in the moments increased substantially when we did not account for changes in the muscles׳ relative EMG intensities with load or, in some subjects, when we used an average stiffness, rather than a subject-specific value. The proposed methods offer a non-invasive approach for studying in vivo muscle-tendon mechanics.
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Affiliation(s)
- Taylor J M Dick
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada.
| | | | - James M Wakeling
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
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24
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How Hinge Positioning in Cross-Country Ski Bindings Affect Exercise Efficiency, Cycle Characteristics and Muscle Coordination during Submaximal Roller Skiing. PLoS One 2016; 11:e0153078. [PMID: 27203597 PMCID: PMC4874670 DOI: 10.1371/journal.pone.0153078] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 03/23/2016] [Indexed: 11/19/2022] Open
Abstract
The purposes of the current study were to 1) test if the hinge position in the binding of skating skis has an effect on gross efficiency or cycle characteristics and 2) investigate whether hinge positioning affects synergistic components of the muscle activation in six lower leg muscles. Eleven male skiers performed three 4-min sessions at moderate intensity while cross-country ski-skating and using a klapskate binding. Three different positions were tested for the binding’s hinge, ranging from the front of the first distal phalange to the metatarsal-phalangeal joint. Gross efficiency and cycle characteristics were determined, and the electromyographic (EMG) signals of six lower limb muscles were collected. EMG signals were wavelet transformed, normalized, joined into a multi-dimensional vector, and submitted to a principle component analysis (PCA). Our results did not reveal any changes to gross efficiency or cycle characteristics when altering the hinge position. However, our EMG analysis found small but significant effects of hinge positioning on muscle coordinative patterns (P < 0.05). The changed patterns in muscle activation are in alignment with previously described mechanisms that explain the effects of hinge positioning in speed-skating klapskates. Finally, the within-subject results of the EMG analysis suggested that in addition to the between-subject effects, further forms of muscle coordination patterns appear to be employed by some, but not all participants.
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Enders H, VON Tscharner V, Nigg BM. Neuromuscular Strategies during Cycling at Different Muscular Demands. Med Sci Sports Exerc 2016; 47:1450-9. [PMID: 25380476 DOI: 10.1249/mss.0000000000000564] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE This study investigated muscle coordination while pedaling at 150 and 300 W with a cadence of 90 rpm. Changes in the variability of the electromyographic (EMG) signals were quantified in 14 subjects. METHODS Principal component analysis was used to find correlated EMG patterns among seven leg muscles that reflect neuromuscular strategies while pedaling. Sample entropy was used to assess the regularity of the short-term fluctuations of the EMG. Signal structure relates to the autocorrelation and to the information in the phase of the signal. This study used the information encrypted in the phase to quantify neuromuscular control and compared the results to phase-randomized surrogate data. RESULTS Although the pattern remained similar, the correlation between individual muscles showed effort-dependent differences. Increased workload altered the overall neuromuscular strategy indicated by changes in the contribution of individual muscles to the movement. Additionally, the executed strategy was characterized by increased structure. Regularity of the short-term fluctuations in the EMG increased significantly with effort level. Both experimental conditions showed more structure in the phase of the EMG compared to the surrogate data. CONCLUSIONS This increased structure in the EMG signal may represent a less random and more orderly recruited firing pattern during the pedaling task at higher effort levels.
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Affiliation(s)
- Hendrik Enders
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, CANADA
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26
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Khanmohammadi R, Talebian S, Hadian MR, Olyaei G, Bagheri H. Characteristic muscle activity patterns during gait initiation in the healthy younger and older adults. Gait Posture 2016; 43:148-53. [PMID: 26497801 DOI: 10.1016/j.gaitpost.2015.09.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 09/06/2015] [Accepted: 09/17/2015] [Indexed: 02/02/2023]
Abstract
It is thought that gait initiation (GI) might be an optimal task for identifying postural control deficiencies. Thus, the aim of this study was to clarify the strategies adopted by older subjects during this task. 16 healthy younger and 15 healthy older adults participated in the study. Subjects were instructed to begin forward stepping with their dominant limb in response to an auditory stimulus. The mean muscle activity, co-contraction index, and intra-subject coefficients of variation (intra-subject CVs) of dominant limb muscles in different phases of GI were measured. The level of association between the co-contraction index and intra-subject CV of muscles was also explored. This study showed that in the anticipatory phase, the younger group had larger amplitudes and more intra-subject CVs than older the group, particularly for the tibialis anterior muscle. However, the co-contraction index was greater in older subjects relative to younger subjects. During the weight transition phase, tibialis anterior, semitendinosus and vastus lateralis muscles of older adults had a lower amplitude as compared to younger adults. However, during the locomotor phase, the activity of tibialis anterior was greater in comparison to younger adults. Also, during this phase, similar to the anticipatory phase, the co-contraction index between tibialis anterior and gastrocnemius muscles was greater in older subjects relative to younger subjects. Additionally, the larger co-contraction index of some muscles was associated with smaller intra-subject CV. These findings suggest that muscle behaviors are altered with aging and older adults employ different strategies in the different phases of GI as compared to younger adults.
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Affiliation(s)
- Roya Khanmohammadi
- Physical Therapy Department, Tehran university of Medical Sciences, Tehran, Iran.
| | - Saeed Talebian
- Physical Therapy Department, Tehran university of Medical Sciences, Tehran, Iran.
| | - Mohammad Reza Hadian
- Physical Therapy Department, Tehran university of Medical Sciences, Tehran, Iran.
| | - Gholamreza Olyaei
- Physical Therapy Department, Tehran university of Medical Sciences, Tehran, Iran.
| | - Hossein Bagheri
- Physical Therapy Department, Tehran university of Medical Sciences, Tehran, Iran.
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Meigal A, Fomina E. Electromyographic evaluation of countermeasures during the terrestrial simulation of interplanetary spaceflight in Mars500 project. ACTA ACUST UNITED AC 2015; 23:11-8. [PMID: 26857518 DOI: 10.1016/j.pathophys.2015.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Revised: 10/16/2015] [Accepted: 10/18/2015] [Indexed: 10/22/2022]
Abstract
The efficiency of six countermeasures (CM) for muscle atrophy was compared over 520 days of confinement during the terrestrial simulation of round space flight to Mars using surface electromyography (sEMG). Three of CM were cyclic exercises (a motor-driven and leg-driven treadmill, cycle ergometer), resistive exercises (the multifunctional dynamometer for space-MDS, and expanders), and vibration platform. Each of CM was applied for each crew member (n=6) once over the experiment, for 70 days in a row, in prescribed order. sEMG was collected during the "force step test" in which the subject voluntarily produced pressure by lower limb, with minimal force increment. The mean frequency (MNF) and average amplitude of sEMG were analyzed. The MNF of sEMG decreased from 104.3±4.2 to 95.3±2.9Hz (P<0.05) in the soleus muscle after 70 days of exercising on the leg-driven treadmill and after 35 days-on vibration platform. It can be caused by earlier (10-250ms) recruitment of the soleus in respect with the medial gastronemius on the leg-driven treadmill, while on the motor-driven treadmill synergists activated synchronously. In other lower leg muscles, MNF decreased from 180 to 200 to 165-180Hz after 70 days of resistive exercises on the MDS device. CM caused no effect on sEMG amplitude. In conclusion, (1) the leg-driven treadmill, the MDS and vibration platform significantly depressed MNF of sEMG of lower extremity muscles; (2) the leg-driven treadmill and vibration platform specifically affected the soleus muscle. Therefore, these CM can be recommended for a more extensive use on ISS board.
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Affiliation(s)
- A Meigal
- Institute of Advanced Biomedical Technologies, Petrozavodsk State University, Petrozavodsk, Russian Federation.
| | - E Fomina
- State Scientific Center of Russian Federation Institute of Biomedical Problems of the Russian Academy of Sciences, Moscow, Russian Federation
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28
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Blake OM, Wakeling JM. Muscle coordination limits efficiency and power output of human limb movement under a wide range of mechanical demands. J Neurophysiol 2015; 114:3283-95. [PMID: 26445873 DOI: 10.1152/jn.00765.2015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/06/2015] [Indexed: 11/22/2022] Open
Abstract
This study investigated the influence of cycle frequency and workload on muscle coordination and the ensuing relationship with mechanical efficiency and power output of human limb movement. Eleven trained cyclists completed an array of cycle frequency (cadence)-power output conditions while excitation from 10 leg muscles and power output were recorded. Mechanical efficiency was maximized at increasing cadences for increasing power outputs and corresponded to muscle coordination and muscle fiber type recruitment that minimized both the total muscle excitation across all muscles and the ineffective pedal forces. Also, maximum efficiency was characterized by muscle coordination at the top and bottom of the pedal cycle and progressive excitation through the uniarticulate knee, hip, and ankle muscles. Inefficiencies were characterized by excessive excitation of biarticulate muscles and larger duty cycles. Power output and efficiency were limited by the duration of muscle excitation beyond a critical cadence (120-140 rpm), with larger duty cycles and disproportionate increases in muscle excitation suggesting deteriorating muscle coordination and limitations of the activation-deactivation capabilities. Most muscles displayed systematic phase shifts of the muscle excitation relative to the pedal cycle that were dependent on cadence and, to a lesser extent, power output. Phase shifts were different for each muscle, thereby altering their mechanical contribution to the pedaling action. This study shows that muscle coordination is a key determinant of mechanical efficiency and power output of limb movement across a wide range of mechanical demands and that the excitation and coordination of the muscles is limited at very high cycle frequencies.
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Affiliation(s)
- Ollie M Blake
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - James M Wakeling
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
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29
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Forman DA, Philpott DTG, Button DC, Power KE. Cadence-dependent changes in corticospinal excitability of the biceps brachii during arm cycling. J Neurophysiol 2015; 114:2285-94. [PMID: 26289462 DOI: 10.1152/jn.00418.2015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 08/19/2015] [Indexed: 11/22/2022] Open
Abstract
This is the first study to report the influence of different cadences on the modulation of supraspinal and spinal excitability during arm cycling. Supraspinal and spinal excitability were assessed using transcranial magnetic stimulation of the motor cortex and transmastoid electrical stimulation of the corticospinal tract, respectively. Transcranial magnetic stimulation-induced motor evoked potentials and transmastoid electrical stimulation-induced cervicomedullary evoked potentials (CMEPs) were recorded from the biceps brachii at two separate positions corresponding to elbow flexion and extension (6 and 12 o'clock relative to a clock face, respectively) while arm cycling at 30, 60 and 90 rpm. Motor evoked potential amplitudes increased significantly as cadence increased during both elbow flexion (P < 0.001) and extension (P = 0.027). CMEP amplitudes also increased with cadence during elbow flexion (P < 0.01); however, the opposite occurred during elbow extension (i.e., decreased CMEP amplitude; P = 0.01). The data indicate an overall increase in the excitability of corticospinal neurons which ultimately project to biceps brachii throughout arm cycling as cadence increased. Conversely, changes in spinal excitability as cadence increased were phase dependent (i.e., increased during elbow flexion and decreased during elbow extension). Phase- and cadence-dependent changes in spinal excitability are suggested to be mediated via changes in the balance of excitatory and inhibitory synaptic input to the motor pool, as opposed to changes in the intrinsic properties of spinal motoneurons.
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Affiliation(s)
- Davis A Forman
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada; and
| | - Devin T G Philpott
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada; and
| | - Duane C Button
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada; and Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Kevin E Power
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada; and Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
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Farris DJ, Lichtwark GA, Brown NAT, Cresswell AG. Deconstructing the power resistance relationship for squats: A joint-level analysis. Scand J Med Sci Sports 2015; 26:774-81. [PMID: 26103786 DOI: 10.1111/sms.12508] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2015] [Indexed: 11/27/2022]
Abstract
Generating high leg power outputs is important for executing rapid movements. Squats are commonly used to increase leg strength and power. Therefore, it is useful to understand factors affecting power output in squatting. We aimed to deconstruct the mechanisms behind why power is maximized at certain resistances in squatting. Ten male rowers (age = 20 ± 2.2 years; height = 1.82 ± 0.03 m; mass = 86 ± 11 kg) performed maximal power squats with resistances ranging from body weight to 80% of their one repetition maximum (1RM). Three-dimensional kinematics was combined with ground reaction force (GRF) data in an inverse dynamics analysis to calculate leg joint moments and powers. System center of mass (COM) velocity and power were computed from GRF data. COM power was maximized across a range of resistances from 40% to 60% 1RM. This range was identified because a trade-off in hip and knee joint powers existed across this range, with maximal knee joint power occurring at 40% 1RM and maximal hip joint power at 60% 1RM. A non-linear system force-velocity relationship was observed that dictated large reductions in COM power below 20% 1RM and above 60% 1RM. These reductions were due to constraints on the control of the movement.
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Affiliation(s)
- D J Farris
- School of Human Movement & Nutrition Sciences, The University of Queensland, Brisbane, Australia.,Movement Science, Australian Institute of Sport, Canberra, Australia
| | - G A Lichtwark
- School of Human Movement & Nutrition Sciences, The University of Queensland, Brisbane, Australia
| | - N A T Brown
- Movement Science, Australian Institute of Sport, Canberra, Australia
| | - A G Cresswell
- School of Human Movement & Nutrition Sciences, The University of Queensland, Brisbane, Australia
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Fabre N, Mourot L, Zoppirolli C, Andersson E, Willis SJ, Holmberg HC. Alterations in aerobic energy expenditure and neuromuscular function during a simulated cross-country skiathlon with the skating technique. Hum Mov Sci 2015; 40:326-40. [PMID: 25681656 DOI: 10.1016/j.humov.2015.01.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 01/18/2015] [Accepted: 01/22/2015] [Indexed: 11/17/2022]
Abstract
Here, we tested the hypothesis that aerobic energy expenditure (AEE) is higher during a simulated 6-km (2 loops of 3-km each) "skiathlon" than during skating only on a treadmill and attempted to link any such increase to biomechanical and neuromuscular responses. Six elite male cross-country skiers performed two pre-testing time-trials (TT) to determine their best performances and to choose an appropriate submaximal speed for collection of physiological, biomechanical and neuromuscular data during two experimental sessions (exp). Each skier used, in randomized order, either the classical (CL) or skating technique (SK) for the first 3-km loop, followed by transition to the skating technique for the second 3-km loop. Respiratory parameters were recorded continuously. The EMG activity of the triceps brachii (TBr) and vastus lateralis (VLa) muscles during isometric contractions performed when the skiers were stationary (i.e., just before the first loop, during the transition, and after the second loop); their corresponding activity during dynamic contractions; and pole and plantar forces during the second loop were recorded. During the second 3-km of the TT, skating speed was significantly higher for the SK-SK than CL-SK. During this second loop, AEE was also higher (+1.5%) for CL-SKexp than SK-SKexp, in association with higher VLa EMG activity during both isometric and dynamic contractions, despite no differences in plantar or pole forces, poling times or cycle rates. Although the underlying mechanism remains unclear, during a skiathlon, the transition between the sections of classical skiing and skating alters skating performance (i.e., skiing speed), AEE and neuromuscular function.
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Affiliation(s)
- Nicolas Fabre
- Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden.
| | - Laurent Mourot
- Research Unit EA4660, Culture Sport Health Society and Exercise Performance Health Innovation Platform, Franche-Comté University, Besançon, France; Clinical Investigation Centre, INSERM CIT 808, CHRU of Besançon, France
| | - Chiara Zoppirolli
- CeRiSM, Center of Research in Mountain Sport and Health, Department of Neurological, Neuropsychological, Morphological and Movement Sciences, University of Verona, Rovereto, Italy
| | - Erik Andersson
- Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Sarah J Willis
- Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Hans-Christer Holmberg
- Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
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Abstract
Previous authors have reported power-pedaling rate relationships for maximal cycling. However, the joint-specific power-pedaling rate relationships that contribute to pedal power have not been reported. We determined absolute and relative contributions of joint-specific powers to pedal power across a range of pedaling rates during maximal cycling. Ten cyclists performed maximal 3 s cycling trials at 60, 90, 120, 150, and 180 rpm. Joint-specific powers were averaged over complete pedal cycles, and extension and flexion actions. Effects of pedaling rate on relative joint-specific power, velocity, and excursion were assessed with regression analyses and repeated-measures ANOVA. Relative ankle plantar flexion power (25 to 8%; P = .01; R(2) = .90) decreased with increasing pedaling rate, whereas relative hip extension power (41 to 59%; P < .01; R(2) = .92) and knee flexion power (34 to 49%; P < .01; R(2) = .94) increased with increasing pedaling rate. Knee extension powers did not differ across pedaling rates. Ankle joint angular excursion decreased with increasing pedaling rate (48 to 20 deg) whereas hip joint excursion increased (42 to 48 deg). These results demonstrate that the often-reported quadratic power-pedaling rate relationship arises from combined effects of dissimilar joint-specific power-pedaling rate relationships. These dissimilar relationships are likely influenced by musculoskeletal constraints (ie, muscle architecture, morphology) and/or motor control strategies.
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Jandacka D, Uchytil J, Farana R, Zahradnik D, Hamill J. Lower extremity power during the squat jump with various barbell loads. Sports Biomech 2014; 13:75-86. [DOI: 10.1080/14763141.2013.872287] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Relative changes in ankle and hip control during bilateral joint movements in persons with multiple sclerosis. Clin Neurophysiol 2013; 125:1192-201. [PMID: 24315810 DOI: 10.1016/j.clinph.2013.11.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 11/08/2013] [Accepted: 11/13/2013] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The purpose of this study was to quantify hip and ankle impairments contributing to movement dysfunction in multiple sclerosis (MS). METHODS Volitional phasing of bilateral hip and ankle torques was assessed using a load-cell-instrumented servomotor drive system in ten participants with MS and 10 age-matched healthy participants. The hips and ankles were separately bilaterally oscillated 180° out of phase (40° range of motion) at a frequency of 0.75 Hz while the other joints were held stationary. Participants were instructed to assist in the same direction as the robot-imposed movement. The hip and ankle torques were measured and work was calculated for each movement. RESULTS Total negative work at the ankle was significantly different between groups (p=0.040). The participants with MS produced larger negative work during hip flexion (p=0.042) and ankle flexion (p=0.037). Negative work at the hip was significantly correlated with the Berg Balance Scores and Timed 25 Feet Walk Test, and trends demonstrated increasing negative work with increasing clinical impairment in MS. CONCLUSIONS These results suggest an increased importance of the hip in functional balance and gait in MS. SIGNIFICANCE Rehabilitation strategies targeting ankle recovery or compensation using the hip might improve movement function in MS.
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Castronovo AM, Conforto S, Schmid M, Bibbo D, D'Alessio T. How to assess performance in cycling: the multivariate nature of influencing factors and related indicators. Front Physiol 2013; 4:116. [PMID: 23734130 PMCID: PMC3659296 DOI: 10.3389/fphys.2013.00116] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 05/03/2013] [Indexed: 12/03/2022] Open
Abstract
Finding an optimum for the cycling performance is not a trivial matter, since the literature shows the presence of many controversial aspects. In order to quantify different levels of performance, several indexes have been defined and used in many studies, reflecting variations in physiological and biomechanical factors. In particular, indexes such as Gross Efficiency (GE), Net Efficiency (NE) and Delta Efficiency (DE) have been referred to changes in metabolic efficiency (EffMet), while the Indexes of Effectiveness (IE), defined over the complete crank revolution or over part of it, have been referred to variations in mechanical effectiveness (EffMech). All these indicators quantify the variations of different factors [i.e., muscle fibers type distribution, pedaling cadence, setup of the bicycle frame, muscular fatigue (MFat), environmental variables, ergogenic aids, psychological traits (PsychTr)], which, moreover, show high mutual correlation. In the attempt of assessing cycling performance, most studies in the literature keep all these factors separated. This may bring to misleading results, leaving unanswered the question of how to improve cycling performance. This work provides an overview on the studies involving indexes and factors usually related to performance monitoring and assessment in cycling. In particular, in order to clarify all those aspects, the mutual interactions among these factors are highlighted, in view of a global performance assessment. Moreover, a proposal is presented advocating for a model-based approach that considers all factors mentioned in the survey, including the mutual interaction effects, for the definition of an objective function E representing the overall effectiveness of a training program in terms of both EffMet and EffMech.
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Affiliation(s)
- A Margherita Castronovo
- Laboratory of Biomedical Engineering - Biolab3, Department of Engineering, University Roma TRE Volterra, Rome, Italy
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Dorel S, Guilhem G, Couturier A, Hug F. Adjustment of muscle coordination during an all-out sprint cycling task. Med Sci Sports Exerc 2013; 44:2154-64. [PMID: 22677928 DOI: 10.1249/mss.0b013e3182625423] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE This study was designed to assess muscle coordination during a specific all-out sprint cycling task (Sprint). The aim was to estimate the EMG activity level of each muscle group by referring to the submaximal cycling condition (Sub150 W) and to test the hypothesis that a maximal activity is reached for all of the muscles during Sprint. METHODS Fifteen well-trained cyclists were tested during submaximal and sprint cycling exercises and a series of maximal voluntary contractions (MVCs) in isometric and isokinetic modes (MVC at the three lower limb joints). Crank torque and surface EMG signals for 11 lower limb muscles were continuously measured. RESULTS Results showed that Sprint induced a very large increase of EMG activity level for the hip flexors (multiplied by 7-9 from 150 W to Sprint) and the knee flexors and hip extensors (multiplied by 5-7), whereas plantar flexors and knee extensors demonstrated a lower increase (multiplied by 2-3). During Sprint, EMG activity level failed to reach a maximal value for hamstrings, tibialis anterior, tensor fasciae latae, and gluteus maximus (i.e., <70% to 80% of peak EMG activity during MVC, P < 0.05 to P < 0.001), and individual EMG patterns demonstrated a significant earlier onset and/or later offset for the majority of the muscles (P < 0.01 to P < 0.001). CONCLUSIONS Results clearly suggest a change in the relative contribution of the different muscles to the power production between Sub150 W and Sprint, and provide evidence that EMG activity level is not systematically maximal for all muscles involved in the all-out sprint cycling task. The longer period of activity induced during Sprint is likely to represent an interesting coordination strategy to enhance the work generated by all of the muscle groups.
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Affiliation(s)
- Sylvain Dorel
- Laboratory Motricité, Interactions, Performance (EA 4334), University of Nantes, Nantes, France.
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Changes in arm coordination and stroke parameters on transition through the lactate threshold. Eur J Appl Physiol 2013; 113:1957-64. [PMID: 23515845 DOI: 10.1007/s00421-013-2617-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 02/15/2013] [Indexed: 10/27/2022]
Abstract
The purpose of the present study was to understand the energetic, biomechanical and coordinative changes occurring throughout the transition of the lactate threshold. Twelve high-level swimmers (six males and six females) performed a paced intermittent incremental protocol of 7 × 200 m (0.05 m s(-1) increments and 30 s intervals). The stroking parameters (stroke rate and stroke length) and the index of coordination (IdC) were assessed by analysis of video recordings from aerial and underwater side-view cameras. Energy cost (C) was determined by the ratio energy expenditure/velocity. Energy expenditure was determined by measuring oxygen uptake VO2 and blood lactate concentrations ([La(-)]). The swimming velocity at the inflection point of stroke rate, stroke length, IdC, VO2, and [La(-)] was determined (m s(-1)). The results showed that stroke rate, stroke length, IdC, VO2, and [La(-)] all exhibited inflection point as a function of swimming velocity, and these velocities were highly correlated with the velocity at [La(-)]inflex (1.35 ± 0.07 m s(-1); R = 0.99, P < 0.001). Furthermore, these values were not significantly different (P > 0.05), and Bland-Altman plots estimations were almost unbiased. These findings seem to confirm that as swimming velocity increases and lactate threshold is surpassed, it induces changes in stroke mechanics and organization suggesting an important biomechanical, coordinative and metabolic boundary between moderate and heavy intensity domains.
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Interplay of biomechanical, energetic, coordinative, and muscular factors in a 200 m front crawl swim. BIOMED RESEARCH INTERNATIONAL 2013; 2013:897232. [PMID: 23586063 PMCID: PMC3613086 DOI: 10.1155/2013/897232] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 02/05/2013] [Indexed: 11/17/2022]
Abstract
This study aimed to determine the relative contribution of selected biomechanical, energetic, coordinative, and muscular factors for the 200 m front crawl and each of its four laps. Ten swimmers performed a 200 m front crawl swim, as well as 50, 100, and 150 m at the 200 m pace. Biomechanical, energetic, coordinative, and muscular factors were assessed during the 200 m swim. Multiple linear regression analysis was used to identify the weight of the factors to the performance. For each lap, the contributions to the 200 m performance were 17.6, 21.1, 18.4, and 7.6% for stroke length, 16.1, 18.7, 32.1, and 3.2% for stroke rate, 11.2, 13.2, 6.8, and 5.7% for intracycle velocity variation in x, 9.7, 7.5, 1.3, and 5.4% for intracycle velocity variation in y, 17.8, 10.5, 2.0, and 6.4% for propelling efficiency, 4.5, 5.8, 10.9, and 23.7% for total energy expenditure, 10.1, 5.1, 8.3, and 23.7% for interarm coordination, 9.0, 6.2, 8.5, and 5.5% for muscular activity amplitude, and 3.9, 11.9, 11.8, and 18.7% for muscular frequency). The relative contribution of the factors was closely related to the task constraints, especially fatigue, as the major changes occurred from the first to the last lap.
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Manimmanakorn A, Manimmanakorn N, Taylor R, Draper N, Billaut F, Shearman JP, Hamlin MJ. Effects of resistance training combined with vascular occlusion or hypoxia on neuromuscular function in athletes. Eur J Appl Physiol 2013; 113:1767-74. [PMID: 23412543 DOI: 10.1007/s00421-013-2605-z] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 02/03/2013] [Indexed: 11/25/2022]
Abstract
The aim was to investigate the effects of low-load resistant training combined with vascular occlusion or normobaric hypoxic exposure, on neuromuscular function. In a randomised controlled trial, well-trained athletes took part in a 5-week training of knee flexor/extensor muscles in which low-load resistant exercise (20% of one repetition maximum, 1-RM) was combined with either (1) an occlusion pressure of approximately 230 mmHg (KT, n = 10), (2) hypoxic air to generate an arterial blood oxygen saturation of ~80% (HT, n = 10), or (3) with no additional stimulus (CT, n = 10). Before and after training, participants completed the following tests: 3-s maximal voluntary contraction (MVC₃), 30-s MVC, and an endurance test (maximal number of repetitions at 20% 1-RM, Reps₂₀). Electromyographic activity (root mean square, RMS) was measured during tests and the cross-sectional area (CSA) of the quadriceps and hamstrings was measured pre- and post-training. Relative to CT, KT, and HT showed likely increases in MVC₃ (11.0 ± 11.9 and 15.0 ± 13.1%, mean ± 90% confidence interval), MVC₃₀ (10.2 ± 9.0 and 18.3 ± 17.4%), and Reps₂₀ (28.9 ± 23.7 and 23.3 ± 24.0%). Compared to the CT group, CSA increased in the KT (7.6 ± 5.8) and HT groups (5.3 ± 3.0). KT had a large effect on RMS during MVC₃, compared to CT (effect size 0.8) and HT (effect size 0.8). We suspect hypoxic conditions created within the muscles during vascular occlusion and hypoxic training may play a key role in these performance enhancements.
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Affiliation(s)
- Apiwan Manimmanakorn
- Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
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Muscle gearing during isotonic and isokinetic movements in the ankle plantarflexors. Eur J Appl Physiol 2012; 113:437-47. [PMID: 22777499 DOI: 10.1007/s00421-012-2448-z] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 06/18/2012] [Indexed: 10/27/2022]
Abstract
Muscle-tendon gearing is the ratio of the muscle-tendon unit velocity to the fascicle velocity and can be expressed as the product of the gearing within the muscle belly and the gearing due to tendon stretch. Previous studies have shown that gearing is variable and increases at higher velocities. Changes in the muscle activation levels and force development have been suggested to affect tendon gearing and thus muscle-tendon unit gearing. However, the role of belly gearing as a part of muscle-tendon gearing and its associations with structural aspects of muscle and thus movement performance are important facets that need to be studied. The two gastrocnemii of twenty young adults were tested during isokinetic and isotonic contractions on an ankle dynamometer. Ultrasound images of both muscles were collected during contractions and were later digitised. Gearing was also predicted using a 2-dimensional panel model of these muscles. The results from experimental and models tests showed increases in gearing with greater torque levels at slower contraction velocities. However, in the isotonic models there was a substantial increase in gearing at faster contraction velocities. The level of muscle-tendon unit gearing is largely determined by the belly gearing, but its variability is driven by changes in tendon gearing that in turn is a factor of the muscle activation and coordination. The belly thickness of the medial gastrocnemius decreased during contractions, but increased for the lateral gastrocnemius. It is likely that changes to the belly shape and 3-dimensional structure are important to the gearing of the muscle.
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BLAKE OLLIEM, CHAMPOUX YVAN, WAKELING JAMESM. Muscle Coordination Patterns for Efficient Cycling. Med Sci Sports Exerc 2012; 44:926-38. [DOI: 10.1249/mss.0b013e3182404d4b] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Relationship between decreased swimming velocity and muscle activity during 200-m front crawl. Eur J Appl Physiol 2012; 112:3417-29. [DOI: 10.1007/s00421-012-2321-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 01/09/2012] [Indexed: 10/14/2022]
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Leontijevic B, Pazin N, Bozic PR, Kukolj M, Ugarkovic D, Jaric S. Effects of loading on maximum vertical jumps: Selective effects of weight and inertia. J Electromyogr Kinesiol 2011; 22:286-93. [PMID: 22209596 DOI: 10.1016/j.jelekin.2011.12.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 11/26/2011] [Accepted: 12/02/2011] [Indexed: 10/14/2022] Open
Abstract
A novel loading method was applied to explore selective effects of externally added weight (W), weight and inertia (W+I), and inertia (I) on maximum counter-movement jumps (CMJ) performed with arm swing. Externally applied extended rubber bands and/or loaded vest added W, W+I, and I corresponding to 10-40% of subjects' body mass. As expected, an increase in magnitude of all types of load was associated with an increase in ground reaction forces (GRF), as well as with a decrease in both the jumping performance and power output. However, of more importance could be that discernible differences among the effects of W, W+I, and I were recorded despite a relatively narrow loading range. In particular, an increase in W was associated with the minimal changes in movement kinematic pattern and smallest reduction of jumping performance, while also allowing for the highest power output. Conversely, W+I was associated with the highest ground reaction forces. Finally, the lowest maxima of GRF and power were associated with I. Although further research is apparently needed, the obtained finding could be of potential importance not only for understanding fundamental properties of the neuromuscular system, but also for optimization of loading in standard athletic training and rehabilitation procedures.
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Affiliation(s)
- Bojan Leontijevic
- The Research Center, Faculty of Sports and Physical Education, University of Belgrade, Belgrade, Serbia
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Abstract
INTRODUCTION/PURPOSE Muscle activity in cycling has primarily been studied in the laboratory; however, conclusions are limited by the ability to recreate realistic environmental conditions. The purpose of this study was to determine muscle coordination patterns in an outdoor time trial and investigate their relationships to power output (PO), total muscle activity (Itot), overall mechanical efficiency (ηO), cadence, and gradient. METHODS Surface EMG, gradient, and cycling parameters were measured while cycling 18.8 km outdoors. A principal component analysis was used to establish coordination patterns that were compared with Itot, ηO, PO, cadence, and gradient. RESULTS PO was positively correlated with Itot, and high PO was associated with elevated rectus femoris and vastus lateralis activity and synchronization of muscles crossing the same joint. PO and cadence demonstrated positive and negative relationships, respectively, with gradient. Relationships between muscle coordination, PO, ηO, Itot, and gradient showed that muscle coordination, PO, and ηO fluctuate during an outdoor time trial as a result of pacing and gradient. A trade-off existed between ηO and PO, and ηO was dependent on muscle activation around the top and bottom of the pedal cycle and activity in more than the knee extensor muscles. Fluctuations in muscle activity due to the changing PO, from pacing and terrain, seemed to mitigate fatigue indices seen in indoor cycling studies. CONCLUSIONS This study provides evidence that muscle activity is dependent on the terrain aspects of the cycle course as muscle coordination changes with the altered locomotor demands. The coordination patterns significantly covaried with PO, Itot, ηO, cadence, and gradient, which highlights the importance of recording these parameters under field conditions and/or careful reproduction of outdoor environments in indoor studies.
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Affiliation(s)
- Ollie M Blake
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada.
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Wakeling JM, Blake OM, Wong I, Rana M, Lee SSM. Movement mechanics as a determinate of muscle structure, recruitment and coordination. Philos Trans R Soc Lond B Biol Sci 2011; 366:1554-64. [PMID: 21502126 DOI: 10.1098/rstb.2010.0294] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
During muscle contractions, the muscle fascicles may shorten at a rate different from the muscle-tendon unit, and the ratio of these velocities is its gearing. Appropriate gearing allows fascicles to reduce their shortening velocities and allows them to operate at effective shortening velocities across a range of movements. Gearing of the muscle fascicles within the muscle belly is the result of rotations of the fascicles and bulging of the belly. Variable gearing can also occur as a result of tendon length changes that can be caused by changes in the relative timing of muscle activity for different mechanical tasks. Recruitment patterns of slow and fast fibres are crucial for achieving optimal muscle performance, and coordination between muscles is related to whole limb performance. Poor coordination leads to inefficiencies and loss of power, and optimal coordination is required for high power outputs and high mechanical efficiencies from the limb. This paper summarizes key studies in these areas of neuromuscular mechanics and results from studies where we have tested these phenomena on a cycle ergometer are presented to highlight novel insights. The studies show how muscle structure and neural activation interact to generate smooth and effective motion of the body.
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Affiliation(s)
- James M Wakeling
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada.
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Theurel J, Crepin M, Foissac M, Temprado JJ. Effects of different pedalling techniques on muscle fatigue and mechanical efficiency during prolonged cycling. Scand J Med Sci Sports 2011; 22:714-21. [PMID: 21507064 DOI: 10.1111/j.1600-0838.2011.01313.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The present study aimed to test the influence of the pedalling technique on the occurrence of muscular fatigue and on the energetic demand during prolonged constant-load cycling exercise. Subjects performed two prolonged (45 min) cycling sessions at constant intensity (75% of maximal aerobic power). In a random order, participants cycled either with their preferred technique (PT) during one session or were helped by a visual force-feedback to modify their pedalling pattern during the other one (FB). Index of pedalling effectiveness was significantly (P<0.05) improved during FB (41.4 ± 5.5%); compared with PT (36.6 ± 4.1%). Prolonged cycling induced a significant reduction of maximal power output, which was greater after PT (-15 ± 9%) than after FB (-7 ± 12%). During steady-state FB, vastus lateralis muscle activity was significantly (P<0.05) reduced, whereas biceps femoris muscles activities increased compared with PT. Gross efficiency (GE) did not significantly differ between the two sessions, except during the first 15 min of exercise (FB: 19.0 ± 1.9% vs PT: 20.2 ± 1.9%). Although changes in muscular coordination pattern with feedback did not seem to influence GE, it could be mainly responsible for the reduction of muscle fatigue after prolonged cycling.
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Affiliation(s)
- J Theurel
- Institute of Movement Sciences E-J Marey, UMR CNRS 6233, Aix-Marseille University, Parc Scientifique et Technologique de Luminy, Marseille, France.
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Effect of power output on muscle coordination during rowing. Eur J Appl Physiol 2011; 111:3017-29. [PMID: 21451939 DOI: 10.1007/s00421-011-1928-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 03/15/2011] [Indexed: 01/08/2023]
Abstract
The present study was designed to quantify the effect of power output on muscle coordination during rowing. Surface electromyographic (EMG) activity of 23 muscles and mechanical variables were recorded in eight untrained subjects and seven experienced rowers. Each subject was asked to perform three 2-min constant-load exercises performed at 60, 90 and 120% of the mean power output over a maximal 2,000-m event (denoted as P60, P90, and P120, respectively). A decomposition algorithm (nonnegative matrix factorization) was used to extract the muscle synergies that represent the global temporal and spatial organization of the motor output. The results showed a main effect of power output for 22 of 23 muscles (p values ranged from <0.0001 to 0.004) indicating a significant increase in EMG activity level with power output for both untrained and experienced subjects. However, for the two populations, no dramatic modification in the shape of individual EMG patterns (mean r (max) value = 0.93 ± 0.09) or in their timing of activation (maximum lag time = -4.3 ± 3.8% of the rowing cycle) was found. The results also showed a large consistency of the three extracted muscle synergies, for both synergy activation coefficients (mean r (max) values range from 0.87 to 0.97) and muscle synergy vectors (mean r values range from 0.70 to 0.76) across the three power outputs. In conclusion, despite significant changes in the level of muscle activity, the global temporal and spatial organization of the motor output is very little affected by power output on a rowing ergometer.
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Place N, Yamada T, Bruton JD, Westerblad H. Muscle fatigue: from observations in humans to underlying mechanisms studied in intact single muscle fibres. Eur J Appl Physiol 2010; 110:1-15. [DOI: 10.1007/s00421-010-1480-0] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2010] [Indexed: 01/01/2023]
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