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Faro Viana F, Cotovio G, da Silva DR, Seybert C, Pereira P, Silva A, Carvalho F, Oliveira-Maia AJ. Reducing motor evoked potential amplitude variability through normalization. Front Psychiatry 2024; 15:1279072. [PMID: 38356910 PMCID: PMC10864444 DOI: 10.3389/fpsyt.2024.1279072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 01/04/2024] [Indexed: 02/16/2024] Open
Abstract
BackgroundTranscranial Magnetic Stimulation (TMS) is used for in vivo assessment of human motor cortical excitability, with application of TMS pulses over the motor cortex resulting in muscle responses that can be recorded with electromyography (EMG) as Motor Evoked Potentials (MEPs). These have been widely explored as potential biomarkers for neuropsychiatric disorders but methodological heterogeneity in acquisition, and inherent high variability, have led to constraints in reproducibility. Normalization, consisting in scaling the signal of interest to a known and repeatable measurement, reduces variability and is standard practice for between-subject comparisons of EMG. The effect of normalization on variability of MEP amplitude has not yet been explored and was assessed here using several methods.MethodsThree maximal voluntary isometric contractions (MVICs) and 40 MEPs were collected from the right hand in healthy volunteers, with a retest session conducted 4 to 8 weeks later. MEP amplitude was normalized using either external references (MVICs) or internal references (extreme MEPs). Iterative re-sampling of 30 normalized MEPs per subject was repeated 5,000 times to define, for each normalization method, distributions for between-subject coefficients of variation (CV) of the mean MEP amplitude. Intra-class correlation coefficients (ICC) were used to assess the impact of normalization on test–retest stability of MEP amplitude measurements.ResultsIn the absence of normalization, MEPs collected from the right hand of 47 healthy volunteers were within reported values regarding between-subject variability (95% confidence intervals for the CV: [1.0567,1.0577]) and showed good temporal stability (ICC = 0.77). Internal reference normalization substantially reduced between-subject variability, by values of up to 64%, while external reference normalization had no impact or increased between-subject variability. Normalization with the smallest references reduced test–retest stability, with use of the largest references resulting in slight reduction or improvement of ICCs. Internal reference normalization using the largest MEPs was found to be robust to several sensitivity analyses.ConclusionInternal, but not external, reference normalization reduces between-subject variability of MEP amplitude, and has a minimal impact on within-subject variability when conducted with the largest references. Additional research is necessary to further validate these normalization methods toward potential use of MEPs as biomarkers of neuropsychiatric disorders.
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Affiliation(s)
- Francisco Faro Viana
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
- Champalimaud Clinical Centre, Champalimaud Foundation, Lisbon, Portugal
| | - Gonçalo Cotovio
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
- Champalimaud Clinical Centre, Champalimaud Foundation, Lisbon, Portugal
- NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisbon, Portugal
- Department of Psychiatry and Mental Health, Centro Hospitalar de Lisboa Ocidental, Lisbon, Portugal
| | - Daniel Rodrigues da Silva
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
- Champalimaud Clinical Centre, Champalimaud Foundation, Lisbon, Portugal
| | - Carolina Seybert
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
- Champalimaud Clinical Centre, Champalimaud Foundation, Lisbon, Portugal
| | - Patrícia Pereira
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
- Champalimaud Clinical Centre, Champalimaud Foundation, Lisbon, Portugal
- Portuguese Red Cross Health School, Lisbon, Portugal
| | - Artur Silva
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
| | - Filipe Carvalho
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
| | - Albino J. Oliveira-Maia
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
- Champalimaud Clinical Centre, Champalimaud Foundation, Lisbon, Portugal
- NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisbon, Portugal
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Lanza MB, Lacerda LT, Gurgel Simões M, Martins-Costa HC, Diniz RC, Chagas MH, Lima FV. Normalization of the electromyography amplitude during a multiple-set resistance training protocol: Reliability and differences between approaches. J Electromyogr Kinesiol 2023; 68:102724. [PMID: 36399915 DOI: 10.1016/j.jelekin.2022.102724] [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: 09/01/2022] [Revised: 10/26/2022] [Accepted: 11/02/2022] [Indexed: 11/14/2022] Open
Abstract
The first aim was to investigate the impact of different electromyography (EMG) parameters as a reference to normalize the EMG amplitude of the superficial quadriceps femoris muscles across different sets of a knee extension exercise. The second aim is to examine the reliability between days of the EMG parameters used as a reference. Eleven young males attended the laboratory on 4 different days and performed one repetition maximum test, maximumvoluntary isometric contractions, and a resistance training protocol until failure. Surface EMG was placed over the rectus femoris, vastus lateralis, and vastus medialis muscles. Seven EMG parameters were calculated from the tasks and used to normalize EMG amplitude measured during the resistance training protocol. A repeated-measures two-way ANOVA was used (normalized EMG amplitude × set) to compare normalized EMG across sets, while an intraclass correlation coefficient, coefficient of variation, and Bland-Altman plots were used to calculate the intra-day reliability of the EMG parameters. The present investigation showed that normalized EMG amplitude of the superficial muscles of the quadriceps measured during a knee extension exercise is influenced by the EMG parameter and depends on the muscle. While rectus femoris and vastus lateralis normalized EMG amplitude presented one parameter among seven showing similar value to the other parameters, VM showed two. Lastly, all EMG parameters for all muscles presented an overall excellent reliability and agreement between days.
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Affiliation(s)
- Marcel B Lanza
- Department of Physical Therapy and Rehabilitation, School of Medicine, University of Maryland, Baltimore, United States.
| | - Lucas T Lacerda
- Weight Training Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Belo Horizonte, Brazil; Department of Physical Education, State University of Minas Gerais, Divinópolis, Brazil
| | - Marina Gurgel Simões
- Weight Training Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Hugo C Martins-Costa
- Department of Physical Education, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Rodrigo C Diniz
- Weight Training Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Mauro H Chagas
- Weight Training Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Fernando V Lima
- Weight Training Laboratory, School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Belo Horizonte, Brazil
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Di Virgilio TG, Ietswaart M, Selvamoorthy R, Hunter AM. The Reliability of Transcranial Magnetic Stimulation-Derived Corticomotor Inhibition as a Brain Health Evaluation Tool in Soccer Players. SPORTS MEDICINE - OPEN 2022; 8:7. [PMID: 35029772 PMCID: PMC8760368 DOI: 10.1186/s40798-021-00399-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 12/21/2021] [Indexed: 11/30/2022]
Abstract
Background The suitability of corticomotor inhibition and corticospinal excitability to measure brain health outcomes and recovery of sport-related head impact (concussion and subconcussion) depends on good inter-day reliability, which is evaluated in this study. Transcranial magnetic stimulation (TMS) reliability in soccer players is assessed by comparing soccer players, for whom reliability on this measure may be reduced due to exposure to head impacts, to generally active individuals not engaged in contact sport. Methods TMS-derived corticomotor inhibition and corticospinal excitability were recorded from the rectus femoris muscle during two testing sessions, spaced 1–2 weeks apart in 19 soccer players (SOC—age 22 ± 3 years) and 20 generally active (CON—age 24 ± 4 years) healthy volunteers. Inter-day reliability between the two time points was quantified by using intra-class correlation coefficients (ICC). Intra-group reliability and group differences on actual measurement values were also explored. Results Good inter-day reliability was evident for corticomotor inhibition (ICCSOC = 0.61; ICCCON = 0.70) and corticospinal excitability (ICCSOC = 0.59; ICCCON = 0.70) in both generally active individuals and soccer players routinely exposed to sport-related head impacts. Corticomotor inhibition showed lower coefficients of variation than excitability for both groups (InhibSOC = 15.2%; InhibCON = 9.7%; ExcitabSOC = 41.6%; ExcitabCON = 39.5%). No group differences between soccer players and generally active individuals were found on the corticomotor inhibition value (p > 0.05), but levels of corticospinal excitability were significantly lower in soccer players (45.1 ± 20.8 vs 85.4 ± 6.2%Mmax, p < 0.0001). Corticomotor inhibition also showed excellent inter-rater reliability (ICC = 0.87). Conclusions Corticomotor inhibition and corticospinal excitability are stable and maintain good degrees of reliability when assessed over different days in soccer players, despite their routine exposure to head impacts. However, based on intra-group reliability and group differences of the levels of excitability, we conclude that corticomotor inhibition is best suited for the evaluation of neuromuscular alterations associated with head impacts in contact sports.
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Svensson F, Aasa U, Strong A. Textile electromyography electrodes reveal differences in lower limb muscle activation during loaded squats when comparing fixed and free barbell movement paths. Front Sports Act Living 2022; 4:1021323. [PMID: 36524056 PMCID: PMC9745169 DOI: 10.3389/fspor.2022.1021323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 11/09/2022] [Indexed: 08/13/2023] Open
Abstract
INTRODUCTION Traditional recordings of muscle activation often involve time-consuming application of surface electrodes affixed to the skin in laboratory environments. The development of textile electromyography (EMG) electrodes now allows fast and unobtrusive assessment of muscle activation in ecologically valid environments. In this study, textile EMG shorts were used to assess whether performing squats with the barbell resting freely on the shoulders or using a Smith machine for a fixed barbell movement path is preferable for maximizing lower limb muscle activation. METHODS Sixteen athletes performed free and fixed barbell squats in a gym with external loads equivalent to their body mass. Quadriceps, hamstrings and gluteus maximus activation was measured bilaterally with textile EMG electrodes embedded in shorts. RESULTS Mean quadriceps activation was greater for the free compared with the fixed movement path for the right (mean difference [MD] 14μV, p = 0.04, ηp 2 = 0.28) and left leg (MD 15μV, p = 0.01, ηp 2 = 0.39) over the entire squat and specifically during the first half of the eccentric phase for the left leg (MD 7μV, p = 0.04, d = 0.56), second half of the eccentric phase for both legs (right leg MD 21μV, p = 0.05, d = 0.54; left leg MD 23μV, p = 0.04, d = 0.52) and the first half of the concentric phase for both legs (right leg MD 24μV, p = 0.04, d = 0.56; left leg MD 15μV, p = 0.01, d = 0.72). Greater hamstrings activation for the free path was seen for the second half of the eccentric phase (left leg MD 4μV, p = 0.03, d = 0.58) and first half of the concentric phase (right leg MD 5μV, p = 0.02, d = 0.72). No significant differences were found for gluteus maximus. DISCUSSION Textile EMG electrodes embedded in shorts revealed that to maximize thigh muscle activity during loaded squats, a free barbell movement path is preferable to a fixed barbell movement path.
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Affiliation(s)
| | | | - Andrew Strong
- Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, Umeå, Sweden
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Bollinger LM, Brantley JT, Carpenter RS, Haydon MA, Best S, Abel MG. Quadriceps electromyography during flywheel-based inertial training (FIT) and dynamic constant external resistance (DCER) squats at similar tempo. Sports Biomech 2022:1-12. [PMID: 35549814 DOI: 10.1080/14763141.2022.2071330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 04/22/2022] [Indexed: 10/18/2022]
Abstract
Flywheel-based iso-inertial training (FIT) has been purported to provide enhanced adaptations to muscle overload compared to dynamic constant external resistance (DCER), but previous studies have not controlled for exercise intensity. We compared quadriceps electromyography (EMG) amplitude between FIT- and DCER-squats with similar tempo. Eleven (5 M and 6F) resistance-trained participants completed sets of five maximal velocity FIT (0.025 kg∙m2) and DCER (55 ± 15 %1RM) squats. Sagittal plane knee joint angles and surface EMG activity of the vastus lateralis (VL), vastus medialis (VM) and rectus femoris (RF) were measured. Repetition time and peak knee angles were similar between FIT and DCER squats. Mean knee angular velocity during the concentric (122.2 ± 23.6 vs. 108.9 ± 22.9, p = 0.022, Cohen's D: 0.820), but not eccentric, phase was significantly greater during FIT. Peak VM (210.4 ± 49.3 vs. 177.5 ± 56.3 %MVIC, p = 0.001; Cohen's D: 1.416), but not VL or RF, EMG amplitude was significantly greater in FIT compared to DCER. Mean EMG amplitude was significantly (p < 0.001) greater during the concentric than the eccentric phase for the VL and VM but not RF. Mean EMG amplitude was not significantly different between modes during either the concentric or eccentric phase. Quadriceps EMG amplitude is largely similar between FIT and DCER squats when matched for movement velocity.
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Affiliation(s)
- Lance M Bollinger
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington U.S.A
| | - Jason T Brantley
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington U.S.A
| | - Rebekah S Carpenter
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington U.S.A
| | - Mariam A Haydon
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington U.S.A
| | - Stuart Best
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington U.S.A
| | - Mark G Abel
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington U.S.A
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Maddox EU, Bennett HJ, Weinhandl JT. Evidence for the use of dynamic maximum normalization method of muscle activation during weighted back squats. J Biomech 2022; 135:111029. [DOI: 10.1016/j.jbiomech.2022.111029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 02/26/2022] [Accepted: 02/28/2022] [Indexed: 11/29/2022]
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Impact of resistance training status on trunk muscle activation in a fatiguing set of heavy back squats. Eur J Appl Physiol 2020; 121:597-608. [PMID: 33206252 PMCID: PMC7862542 DOI: 10.1007/s00421-020-04540-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 10/22/2020] [Indexed: 11/24/2022]
Abstract
Purpose In this study we measured neural activation (EMG) in four trunk stabilizer muscles and vastus lateralis (VL) in trained and novice participants during a set of squat repetitions to volitional fatigue at 85% 1RM. Methods Forty males were recruited into two groups, novice (NG: n = 21) and experienced (EG: n = 19), according to relative squat 1RM. Participants were tested twice to: (1) determine squat 1RM, and (2) complete a single set of repetitions to volitional fatigue at 85% 1RM. Relative squat 1RM; NG < 140% body mass, EG > 160% body mass. Neuromuscular activation was measured by EMG for the following: rectus abdominus (RA), external oblique (EO), lumbar sacral erector spinae (LSES), upper lumbar erector spinae (ULES) and VL in eccentric and concentric phase. Completed repetitions, RPE and EMG in repetition 1 and at 20, 40, 60, 80 and 100% of completed repetitions were analysed. Results No group differences were found between number repetitions completed and RPE in repetitions to volitional fatigue at 85% 1RM. Neuromuscular activation increased significantly in all muscle groups in eccentric and concentric phase apart from RA in the eccentric phase. Trunk neuromuscular activation was higher in NG compared to EG and this was significant in EO, LSES and ULES in eccentric phase and LSES in the concentric phase. VL activation increased in both phases with no group differences. Conclusion Trunk neuromuscular activation increases in a fatiguing set of heavy squats regardless of training status. Increased back squat strength through training results in lower neuromuscular activation despite greater absolute external squat loads.
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Clark DR, Lambert MI, Grigson C, Hunter AM. Increased strength is associated with lower trunk muscle activation during loaded back squats and dynamic body weight jumps. TRANSLATIONAL SPORTS MEDICINE 2020. [DOI: 10.1002/tsm2.97] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- David R. Clark
- School of Sport and Exercise Sciences, Faculty of Science Liverpool John Moore’s University Liverpool UK
- Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport University of Stirling Stirling UK
| | - Michael I. Lambert
- Division of Exercise Science and Sports Medicine, Department of Human Biology University of Cape Town Cape Town South Africa
| | - Chris Grigson
- Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport University of Stirling Stirling UK
| | - Angus M. Hunter
- Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport University of Stirling Stirling UK
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Reece MB, Arnold GP, Nasir S, Wang WW, Abboud R. Barbell back squat: how do resistance bands affect muscle activation and knee kinematics? BMJ Open Sport Exerc Med 2020; 6:e000610. [PMID: 32095265 PMCID: PMC7010994 DOI: 10.1136/bmjsem-2019-000610] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2020] [Indexed: 12/02/2022] Open
Abstract
Objectives This study aimed to determine whether looped resistance bands affect knee kinematics and lower body muscle activation during the barbell back squat. Methods Twenty-six healthy participants (13 female, 13 male) calculated their one repetition maximum (RM) prior to data collection. Each participant performed three squats at both 80% and 40% 1RM wearing a light resistance band, an extra-heavy resistance band and no resistance band. Vicon 3D motion analysis cameras were used to collect the kinematic data, and Delsys Trigno Lab wireless electromyography (EMG) system was used to measure vastus medialis, vastus lateralis, gluteus maximus, gluteus medius and biceps femoris muscle activity. Peak knee flexion angle, peak knee valgus angle and maximum tibial rotation values were examined. Peak EMG values were also analysed after being normalised and expressed as a percentage of maximum voluntary contraction (MVC). Results Gluteus maximus (GM) activity is significantly increased when a resistance band is used during squatting. However, squatting with a resistance band is detrimental to knee kinematics as it leads to an increase in knee valgus angle and maximum tibial rotation angle. A direct correlation is recorded between an increase in resistance and an increase in these two angles. Conclusions Squatting with resistance bands is likely to increase the risk of knee injury. Coaches and clinicians who already implement this technique are advised to remove resistance band squats from training and rehabilitation programmes. Further research evaluating the long-term effects of using resistance bands during the barbell back squat should be considered.
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Affiliation(s)
- Madeleine B Reece
- nstitute of Motion Analysis & Research (IMAR), University of Dundee, Dundee, UK
| | - Graham P Arnold
- nstitute of Motion Analysis & Research (IMAR), University of Dundee, Dundee, UK
| | - Sadiq Nasir
- nstitute of Motion Analysis & Research (IMAR), University of Dundee, Dundee, UK
| | - Weijie W Wang
- nstitute of Motion Analysis & Research (IMAR), University of Dundee, Dundee, UK
| | - Rami Abboud
- Dean's Office, University of Balamand Faculty of Engineering, El-Koura, Lebanon
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Clark DR, Lambert MI, Hunter AM. Trunk Muscle Activation in the Back and Hack Squat at the Same Relative Loads. J Strength Cond Res 2019; 33 Suppl 1:S60-S69. [DOI: 10.1519/jsc.0000000000002144] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Chiu LZF. Biomechanical Methods to Quantify Muscle Effort During Resistance Exercise. J Strength Cond Res 2018; 32:502-513. [PMID: 29120981 DOI: 10.1519/jsc.0000000000002330] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Chiu, LZF. Biomechanical methods to quantify muscle effort during resistance exercise. J Strength Cond Res 32(2): 502-513, 2018-Muscle hypertrophy and strength adaptations elicited by resistance training are dependent on the force exerted by active muscles. As an exercise may use many muscles, determining force for individual muscles or muscle groupings is important to understand the relation between an exercise and these adaptations. Muscle effort-the amount of force or a surrogate measure related to the amount of force exerted during a task-can be quantified using biomechanical methods. The purpose of this review was to summarize the biomechanical methods used to estimate muscle effort in movements, particularly resistance training exercises. These approaches include the following: (a) inverse dynamics with rigid body models, (b) forward dynamics and EMG-driven models, (c) normalized EMG, and (d) inverse dynamics with point-mass models. Rigid body models quantify muscle effort as net joint moments. Forward dynamics and EMG-driven models estimate muscle force as well as determine the effect of a muscle's action throughout the body. Nonlinear relations between EMG and muscle force and normalization reference action selection affect the usefulness of EMG as a measure of muscle effort. Point-mass models include kinetics calculated from barbell (or other implement) kinematics recorded using electromechanical transducers or measured using force platforms. Point-mass models only allow the net force exerted on the barbell or lifter-barbell system to be determined, so they cannot be used to estimate muscle effort. Data from studies using rigid body models, normalized EMG, and musculoskeletal modeling should be combined to develop hypotheses regarding muscle effort; these hypotheses should be verified by training interventions.
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Affiliation(s)
- Loren Z F Chiu
- Neuromusculoskeletal Mechanics Research Program, Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada
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Macgregor LJ, Fairweather MM, Bennett RM, Hunter AM. The Effect of Foam Rolling for Three Consecutive Days on Muscular Efficiency and Range of Motion. SPORTS MEDICINE-OPEN 2018; 4:26. [PMID: 29884972 PMCID: PMC5993692 DOI: 10.1186/s40798-018-0141-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 05/27/2018] [Indexed: 11/10/2022]
Abstract
BACKGROUND Foam rolling (FR) has been shown to alleviate some symptoms of exercise-induced muscle damage and has been suggested to increase range of motion (ROM) without negatively impacting strength. However, it is unclear what neuromuscular effects, if any, mediate these changes. METHODS In a randomized, crossover design, 16 healthy active males completed 2 min of rest or FR of the knee extensors on three consecutive days. Mechanical properties of vastus lateralis (VL) and rectus femoris (RF) were assessed via Tensiomyography. Knee extension maximal voluntary contraction (MVC) and knee flexion ROM were also assessed, and surface electromyography amplitude (RMS) was recorded during a submaximal isometric contraction (50% of MVC). Measures were performed before and after (0, 15, and 30 min) FR or rest. RESULTS MVC was reduced on subsequent days in the rest condition compared to FR (p = 0.002, pη2 = 0.04); ROM was not different across time or condition (p = 0.193, pη2 = 0.01). Stiffness characteristics of the VL were different on the third day of FR (p = 0.002, pη2 = 0.03). RMS was statistically reduced 0, 15, and 30 min after FR compared to rest (p = 0.006, pη2 = 0.03; p = 0.003, pη2 = 0.04; p = 0.002, pη2 = 0.04). CONCLUSIONS Following FR, MVC was elevated compared to rest and RMS was transiently reduced during a submaximal task. Excitation efficiency of the involved muscles may have been enhanced by FR, which protected against the decline in MVC which was observed with rest.
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Affiliation(s)
- Lewis J Macgregor
- Faculty of Health Sciences and Sport, University of Stirling, Stirling, UK.
| | | | - Ryan M Bennett
- Faculty of Health Sciences and Sport, University of Stirling, Stirling, UK
| | - Angus M Hunter
- Faculty of Health Sciences and Sport, University of Stirling, Stirling, UK
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Macgregor LJ, Hunter AM. High-threshold motor unit firing reflects force recovery following a bout of damaging eccentric exercise. PLoS One 2018; 13:e0195051. [PMID: 29630622 PMCID: PMC5890972 DOI: 10.1371/journal.pone.0195051] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 03/11/2018] [Indexed: 11/18/2022] Open
Abstract
Exercise-induced muscle damage (EIMD) is associated with impaired muscle function and reduced neuromuscular recruitment. However, motor unit firing behaviour throughout the recovery period is unclear. EIMD impairment of maximal voluntary force (MVC) will, in part, be caused by reduced high-threshold motor unit firing, which will subsequently increase to recover MVC. Fourteen healthy active males completed a bout of eccentric exercise on the knee extensors, with measurements of MVC, rate of torque development and surface electromyography performed pre-exercise and 2, 3, 7 and 14 days post-exercise, on both damaged and control limb. EIMD was associated with decreased MVC (235.2 ± 49.3 Nm vs. 161.3 ± 52.5 Nm; p <0.001) and rate of torque development (495.7 ± 136.9 Nm.s-1 vs. 163.4 ± 163.7 Nm.s-1; p <0.001) 48h post-exercise. Mean motor unit firing rate was reduced (16.4 ± 2.2 Hz vs. 12.6 ± 1.7 Hz; p <0.01) in high-threshold motor units only, 48h post-exercise, and common drive was elevated (0.36 ± 0.027 vs. 0.56 ± 0.032; p< 0.001) 48h post-exercise. The firing rate of high-threshold motor units was reduced in parallel with impaired muscle function, whilst early recruited motor units remained unaltered. Common drive of motor units increased in offset to the firing rate impairment. These alterations correlated with the recovery of force decrement, but not of pain elevation. This study provides fresh insight into the central mechanisms associated with EIMD recovery, relative to muscle function. These findings may in turn lead to development of novel management and preventative procedures.
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Affiliation(s)
- Lewis J. Macgregor
- Faculty of Health Sciences and Sport, University of Stirling, Stirling, Scotland
| | - Angus M. Hunter
- Faculty of Health Sciences and Sport, University of Stirling, Stirling, Scotland
- * E-mail:
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Balshaw TG, Fry A, Maden-Wilkinson TM, Kong PW, Folland JP. Reliability of quadriceps surface electromyography measurements is improved by two vs. single site recordings. Eur J Appl Physiol 2017; 117:1085-1094. [PMID: 28391392 PMCID: PMC5427161 DOI: 10.1007/s00421-017-3595-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 03/23/2017] [Indexed: 12/01/2022]
Abstract
Purpose The reliability of surface electromyography (sEMG) is typically modest even with rigorous methods, and therefore further improvements in sEMG reliability are desirable. This study compared the between-session reliability (both within participant absolute reliability and between-participant relative reliability) of sEMG amplitude from single vs. average of two distinct recording sites, for individual muscle (IM) and whole quadriceps (WQ) measures during voluntary and evoked contractions. Methods Healthy males (n = 20) performed unilateral isometric knee extension contractions: voluntary maximum and submaximum (60%), as well as evoked twitch contractions on two separate days. sEMG was recorded from two distinct sites on each superficial quadriceps muscle. Results Averaging two recording sites vs. using single site measures improved reliability for IM and WQ measurements during voluntary (16–26% reduction in within-participant coefficient of variation, CVW) and evoked contractions (40–56% reduction in CVW). Conclusions For sEMG measurements from large muscles, averaging the recording of two distinct sites is recommended as it improves within-participant reliability. This improved sensitivity has application to clinical and research measurement of sEMG amplitude.
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Affiliation(s)
- T G Balshaw
- School of Sport, Exercise, and Health Sciences, Loughborough University, Leicestershire, LE11 3TU, UK. .,Institute for Sports Research, Nanyang Technological University, Singapore, Singapore. .,Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, Loughborough University, Leicestershire, UK.
| | - A Fry
- School of Sport, Exercise, and Health Sciences, Loughborough University, Leicestershire, LE11 3TU, UK
| | - T M Maden-Wilkinson
- School of Sport, Exercise, and Health Sciences, Loughborough University, Leicestershire, LE11 3TU, UK.,Faculty of Health and Wellbeing, Collegiate Campus, Sheffield Hallam University, Sheffield, UK
| | - P W Kong
- Institute for Sports Research, Nanyang Technological University, Singapore, Singapore.,Physical Education and Sports Science Academic Group, National Institute of Education, Nanyang Technological University, Singapore, Singapore
| | - J P Folland
- School of Sport, Exercise, and Health Sciences, Loughborough University, Leicestershire, LE11 3TU, UK.,Institute for Sports Research, Nanyang Technological University, Singapore, Singapore.,Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, Loughborough University, Leicestershire, UK
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15
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Dugdale JH, Hunter AM, Di Virgilio TG, Macgregor LJ, Hamilton DL. Influence of the "Slingshot" Bench Press Training Aid on Bench Press Kinematics and Neuromuscular Activity in Competitive Powerlifters. J Strength Cond Res 2017; 33:327-336. [PMID: 28234710 DOI: 10.1519/jsc.0000000000001853] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Dugdale, JH, Hunter, AM, Di Virgilio, TG, Macgregor, LJ, and Hamilton, DL. Influence of the "Slingshot" bench press training aid on bench press kinematics and neuromuscular activity in competitive powerlifters. J Strength Cond Res 33(2): 327-336, 2019-This study examined the acute effects of the "Slingshot" (SS) on bench press performance, prime mover surface electromyographic (sEMG) amplitude, and barbell velocity during maximal and submaximal bench pressing in competitive male powerlifters. Fifteen male powerlifters (mean ± SD; age: 27.05 ± 5.94 years; mass: 94.15 ± 13.43 kg; 1 repetition maximum [1RM] bench press: 139.7 ± 16.79 kg) participated in the study. Bench press strength, average barbell velocity, and sEMG amplitude of the prime mover muscles (triceps brachii, pectoralis major, and anterior deltoid) were measured during 2 conditions; "Raw" (without use of any assistance) and "SS" (using the "Slingshot" to perform both the weight achieved during "Raw" 1RM testing [Raw max/SS], and absolute 1RM using the "SS"). The results showed that the "SS" significantly increased bench press 1RM performance by a mean ± SD of 20.67 ± 3.4 kg. Barbell velocity and stick point analysis indicate that this improvement is likely driven by an increase in peak and prestick barbell velocity as triceps root mean square (RMS) was lower throughout all rep max phases with the "SS." The "SS" also caused reductions in RMS, specifically of the triceps at all rep ranges but barbell velocity was better maintained in the last reps of all sets. These data indicate that the "SS" specifically deloaded the triceps muscle throughout all rep ranges and provide assistance to maintaining barbell velocity under fatigue during later repetitions of multiple repetition sets. The "SS" training aid could therefore be used in deload phases of bench press training or as an overreaching and velocity training aid.
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Affiliation(s)
- James H Dugdale
- Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, United Kingdom
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16
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Balshaw TG, Pahar M, Chesham R, Macgregor LJ, Hunter AM. Reduced firing rates of high threshold motor units in response to eccentric overload. Physiol Rep 2017; 5:e13111. [PMID: 28108648 PMCID: PMC5269413 DOI: 10.14814/phy2.13111] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 12/08/2016] [Accepted: 12/09/2016] [Indexed: 11/24/2022] Open
Abstract
Acute responses of motor units were investigated during submaximal voluntary isometric tasks following eccentric overload (EO) and constant load (CL) knee extension resistance exercise. Ten healthy resistance-trained participants performed four experimental test sessions separated by 5 days over a 20 day period. Two sessions involved constant load and the other two used eccentric overload. EO and CL used both sessions for different target knee eccentric extension phases; one at 2 sec and the other at 4 sec. Maximal voluntary contractions (MVC) and isometric trapezoid efforts for 10 sec at 70% MVC were completed before and after each intervention and decomposed electromyography was used to measure motor unit firing rate. The firing rate of later recruited, high-threshold motor units declined following the 2-sec EO but was maintained following 2sec CL (P < 0.05), whereas MUFR for all motor units were maintained for both loading types following 4-sec extension phases. MVC and rate of force development where maintained following both EO and CL and 2 and 4 sec phases. This study demonstrates a slower firing rate of high-threshold motor units following fast eccentric overload while MVC was maintained. This suggests that there was a neuromuscular stimulus without cost to the force-generating capacity of the knee extensors.
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Affiliation(s)
- Tom G Balshaw
- Physiology, Exercise and Nutrition Research Group, University of Stirling, Stirling, Scotland, United Kingdom
| | - Madhu Pahar
- Computing Science and Mathematics, University of Stirling, Stirling, Scotland, United Kingdom
| | - Ross Chesham
- Physiology, Exercise and Nutrition Research Group, University of Stirling, Stirling, Scotland, United Kingdom
| | - Lewis J Macgregor
- Physiology, Exercise and Nutrition Research Group, University of Stirling, Stirling, Scotland, United Kingdom
| | - Angus M Hunter
- Physiology, Exercise and Nutrition Research Group, University of Stirling, Stirling, Scotland, United Kingdom
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17
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Zacaron KAM, Dias JMD, Alencar MA, Almeida LLD, Alberto Mourão-Júnior C, Dias RC. Electromyographic normalization of vastus lateralis and biceps femoris co-contraction during gait of elderly females. FISIOTERAPIA EM MOVIMENTO 2016. [DOI: 10.1590/1980-5918.029.004.ao15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Abstract Introduction: Analyze muscle co-contraction using electromyographic signals, which are normalized to compare individuals, muscles and studies. Maximum voluntary isometric contraction (MVIC) and peak electrical activity (PEA) during movement are the most widely used forms of normalization. Objective: Compare inter-subject variability and investigate the association between the co-contraction indices of the vastus lateralis and biceps femoris during gait, normalized by MVIC and PEA. Methods: Thirty elderly women, aged 70.33 ± 3.69 years took part. Electrical muscle activity during MVIC and gait was recorded using a Biopac MP100 electromyograph. MVIC was performed in a Biodex isokinetic dynamometer. For normalization, the signals were divided by the Root Mean Square values of MVIC and PEA of gait. Results: The coefficient of variation of non-normalized data was 69.3%, and those normalized by PEA and MVIC were 30.4% and 48.9% respectively. Linear regression analysis resulted in a prediction model: PEA = 0.04 + 0.16 x MVIC. The goodness of fit of the regression model was statistically significant (p=0.02). The confidence interval (95% CI) for the intercept was between 0.02 and 0.29 and for MVIC between 0.03 and 0.06. Conclusions: The data normalized by PEA showed less variation than those normalized by MVIC. A 100% variation in data normalized by MVIC resulted in a 16% variation in data normalized by PEA, while variation in normalization by MVIC accounts for 17% of the variation in normalization by PEA and vice versa.
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Affiliation(s)
| | | | - Mariana Asmar Alencar
- Universidade Federal de Minas Gerais, Brazil; Universidade Fundação Mineira de Educação e Cultura, Brazil
| | | | | | - Rosângela Correa Dias
- Universidade Federal de Minas Gerais, Brazil; Universidade Federal de São Paulo, Brazil
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18
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Vázquez-Guerrero J, Moras G, Baeza J, Rodríguez-Jiménez S. Force Outputs during Squats Performed Using a Rotational Inertia Device under Stable versus Unstable Conditions with Different Loads. PLoS One 2016; 11:e0154346. [PMID: 27111766 PMCID: PMC4844129 DOI: 10.1371/journal.pone.0154346] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 04/12/2016] [Indexed: 11/27/2022] Open
Abstract
The purpose of the study was to compare the force outputs achieved during a squat exercise using a rotational inertia device in stable versus unstable conditions with different loads and in concentric and eccentric phases. Thirteen male athletes (mean ± SD: age 23.7 ± 3.0 years, height 1.80 ± 0.08 m, body mass 77.4 ± 7.9 kg) were assessed while squatting, performing one set of three repetitions with four different loads under stable and unstable conditions at maximum concentric effort. Overall, there were no significant differences between the stable and unstable conditions at each of the loads for any of the dependent variables. Mean force showed significant differences between some of the loads in stable and unstable conditions (P < 0.010) and peak force output differed between all loads for each condition (P < 0.045). Mean force outputs were greater in the concentric than in the eccentric phase under both conditions and with all loads (P < 0.001). There were no significant differences in peak force between concentric and eccentric phases at any load in either stable or unstable conditions. In conclusion, squatting with a rotational inertia device allowed the generation of similar force outputs under stable and unstable conditions at each of the four loads. The study also provides empirical evidence of the different force outputs achieved by adjusting load conditions on the rotational inertia device when performing squats, especially in the case of peak force. Concentric force outputs were significantly higher than eccentric outputs, except for peak force under both conditions. These findings support the use of the rotational inertia device to train the squatting exercise under unstable conditions for strength and conditioning trainers. The device could also be included in injury prevention programs for muscle lesions and ankle and knee joint injuries.
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Affiliation(s)
- Jairo Vázquez-Guerrero
- Sport Performance, Institut Nacional d’Educació Física de Catalunya, Centre de Barcelona, Barcelona, Spain
- FCBarcelona, Barcelona, Spain
| | - Gerard Moras
- Sport Performance, Institut Nacional d’Educació Física de Catalunya, Centre de Barcelona, Barcelona, Spain
- * E-mail:
| | - Jennifer Baeza
- Fundació Universitària del Bages, Manresa, Barcelona, Spain
| | - Sergio Rodríguez-Jiménez
- Sport Performance, Institut Nacional d’Educació Física de Catalunya, Centre de Barcelona, Barcelona, Spain
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Valentin S, Licka TF. Spinal Motion and Muscle Activity during Active Trunk Movements - Comparing Sheep and Humans Adopting Upright and Quadrupedal Postures. PLoS One 2016; 11:e0146362. [PMID: 26741136 PMCID: PMC4704739 DOI: 10.1371/journal.pone.0146362] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Accepted: 12/16/2015] [Indexed: 11/23/2022] Open
Abstract
Sheep are used as models for the human spine, yet comparative in vivo data necessary for validation is limited. The purpose of this study was therefore to compare spinal motion and trunk muscle activity during active trunk movements in sheep and humans. Three-dimensional kinematic data as well as surface electromyography (sEMG) of spinal flexion and extension was compared in twenty-four humans in upright (UR) and 4-point kneeling (KN) postures and in 17 Austrian mountain sheep. Kinematic markers were attached over the sacrum, posterior iliac spines, and spinous and transverse processes of T5, T8, T11, L2 and L5 in humans and over the sacrum, tuber sacrale, T5, T8, T12, L3 and L7 in sheep. The activity of erector spinae (ES), rectus abdominis (RA), obliquus externus (OE), and obliquus internus (OI) were collected. Maximum sEMG (MOE) was identified for each muscle and trial, and reported as a percentage (MOE%) of the overall maximally observed sEMG from all trials. Spinal range of motion was significantly smaller in sheep compared to humans (UR / KN) during flexion (sheep: 6–11°; humans 12–34°) and extension (sheep: 4°; humans: 11–17°). During extension, MOE% of ES was greater in sheep (median: 77.37%) than UR humans (24.89%), and MOE% of OE and OI was greater in sheep (OE 76.20%; OI 67.31%) than KN humans (OE 21.45%; OI 19.34%), while MOE% of RA was lower in sheep (21.71%) than UR humans (82.69%). During flexion, MOE% of RA was greater in sheep (83.09%) than humans (KN 47.42%; UR 41.38%), and MOE% of ES in sheep (45.73%) was greater than KN humans (14.45%), but smaller than UR humans (72.36%). The differences in human and sheep spinal motion and muscle activity suggest that caution is warranted when ovine data are used to infer human spine biomechanics.
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Affiliation(s)
- Stephanie Valentin
- Equine Clinic, University of Veterinary Medicine Vienna, Vienna, Austria
- * E-mail:
| | - Theresia F. Licka
- Equine Clinic, University of Veterinary Medicine Vienna, Vienna, Austria
- Large Animal Hospital, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, Scotland, United Kingdom
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20
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Yavuz HU, Erdağ D, Amca AM, Aritan S. Kinematic and EMG activities during front and back squat variations in maximum loads. J Sports Sci 2015; 33:1058-66. [DOI: 10.1080/02640414.2014.984240] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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21
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Avoiding Systematic Errors in Isometric Squat-Related Studies without Pre-Familiarization by Using Sufficient Numbers of Trials. J Hum Kinet 2014; 42:201-13. [PMID: 25414753 PMCID: PMC4234759 DOI: 10.2478/hukin-2014-0074] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
There is no scientific evidence in the literature indicating that maximal isometric strength measures can be assessed within 3 trials. We questioned whether the results of isometric squat-related studies in which maximal isometric squat strength (MISS) testing was performed using limited numbers of trials without pre-familiarization might have included systematic errors, especially those resulting from acute learning effects. Forty resistance-trained male participants performed 8 isometric squat trials without pre-familiarization. The highest measures in the first “n” trials (3 ≤ n ≤ 8) of these 8 squats were regarded as MISS obtained using 6 different MISS test methods featuring different numbers of trials (The Best of n Trials Method [BnT]). When B3T and B8T were paired with other methods, high reliability was found between the paired methods in terms of intraclass correlation coefficients (0.93–0.98) and coefficients of variation (3.4–7.0%). The Wilcoxon’s signed rank test indicated that MISS obtained using B3T and B8T were lower (p < 0.001) and higher (p < 0.001), respectively, than those obtained using other methods. The Bland-Altman method revealed a lack of agreement between any of the paired methods. Simulation studies illustrated that increasing the number of trials to 9–10 using a relatively large sample size (i.e., ≥ 24) could be an effective means of obtaining the actual MISS values of the participants. The common use of a limited number of trials in MISS tests without pre-familiarization appears to have no solid scientific base. Our findings suggest that the number of trials should be increased in commonly used MISS tests to avoid learning effect-related systematic errors.
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Rota S, Rogowski I, Champely S, Hautier C. Reliability of EMG normalisation methods for upper-limb muscles. J Sports Sci 2013; 31:1696-704. [DOI: 10.1080/02640414.2013.796063] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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