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Abboud J, Lessard A, Descarreaux M. Superficial lumbar muscle recruitment strategies to control the trunk with delayed-onset muscle soreness. Eur J Appl Physiol 2021; 121:2573-2583. [PMID: 34095975 DOI: 10.1007/s00421-021-04732-2] [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: 10/14/2020] [Accepted: 05/27/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE The lumbar region offers various muscle recruitment strategies to achieve a task goal under varying conditions. For instance, trunk movement control can be reorganized under the influence of low back pain. How such task-modulation is obtained is not fully understood. The objective of this study was to characterize superficial lumbar muscle recruitment strategies under the influence of delayed-onset muscle soreness (DOMS) during unexpected trunk perturbations. METHODS Healthy participants experienced a series of 15 sudden external perturbations with and without the influence of low back DOMS. During these perturbations, high-density surface electromyography was used to characterize recruitment strategies of superficial lumbar muscles, while kinematics sensors were used to characterize movements of the trunk. Lumbar muscle recruitment strategies, characterized by the amplitude of muscle activity amplitude, the latencies of the reflex activity and the spatial distribution of muscle activity, were compared across perturbations trials and with and without DOMS. RESULTS An attenuation of lumbar muscle activity amplitude was observed across perturbation trials without DOMS, but not with DOMS. The spatial distribution of muscle activity was similar with and without DOMS. No significant changes in reflex activity latency and trunk flexion movement were observed. CONCLUSIONS Following an unexpected trunk perturbation under DOMS effects, trunk movement are controlled using two different superficial lumbar muscles control strategies: keeping a constant level of their overall muscle activity and using a variable muscle recruitment pattern.
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Affiliation(s)
- Jacques Abboud
- Department of Human Kinetics, Université du Québec À Trois-Rivières, 3351 Boul. des Forges, C.P. 500, Trois-Rivières, QC, G8Z 4M3, Canada.
| | - Arianne Lessard
- Department of Human Kinetics, Université du Québec À Trois-Rivières, 3351 Boul. des Forges, C.P. 500, Trois-Rivières, QC, G8Z 4M3, Canada
| | - Martin Descarreaux
- Department of Human Kinetics, Université du Québec À Trois-Rivières, 3351 Boul. des Forges, C.P. 500, Trois-Rivières, QC, G8Z 4M3, Canada
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Koblauch H, Zebis MK, Jacobsen MH, Haraldsson BT, Klinge KP, Alkjær T, Bencke J, Andersen LL. Influence of Wearing Ballistic Vests on Physical Performance of Danish Police Officers: A Cross-Over Study. SENSORS 2021; 21:s21051795. [PMID: 33807527 PMCID: PMC7961692 DOI: 10.3390/s21051795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 02/25/2021] [Accepted: 03/02/2021] [Indexed: 11/18/2022]
Abstract
Purpose: We aimed to investigate the influence of wearing a ballistic vest on physical performance in police officers. Methods: We performed a cross-over study to investigate the influence of wearing a ballistic vest on reaction and response time, lumbar muscle endurance and police vehicle entry and exit times. Reaction and response time was based on a perturbation setup where the officers’ pelvises were fixed and EMG of lumbar and abdominal muscles was recorded. We used a modified Biering–Sørensen test to assess the lumbar muscle endurance and measured duration of entry and exit maneuvers in a variety of standard-issue police cars. Results: There was a significant difference of 24% in the lumbar muscle endurance test (no vest: 151 s vs. vest: 117 s), and the police officers experienced higher physical fatigue after the test when wearing a vest. Furthermore, officers took longer to both enter and exit police cars when wearing a vest (range: 0.24–0.56 s) depending on the model of the vehicle. There were no significant differences in reaction and response times between the test conditions (with/without vest). Discussion and Conclusion: Wearing of a ballistic vest significantly influenced the speed of movement in entry and exit of police cars and lumbar muscle endurance, although it does not seem to affect reaction or response times. The ballistic vest seems to impair performance of tasks that require maximal effort, which calls for better designs of such vests.
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Affiliation(s)
- Henrik Koblauch
- Department of Physiotherapy, University College Copenhagen, 2200 Copenhagen N, Denmark; (M.K.Z.); (B.T.H.)
- Correspondence: ; Tel.: +45-41898802
| | - Mette K. Zebis
- Department of Physiotherapy, University College Copenhagen, 2200 Copenhagen N, Denmark; (M.K.Z.); (B.T.H.)
| | - Mikkel H. Jacobsen
- Department of Occupational Therapy, University College Copenhagen, 2200 Copenhagen N, Denmark;
| | - Bjarki T. Haraldsson
- Department of Physiotherapy, University College Copenhagen, 2200 Copenhagen N, Denmark; (M.K.Z.); (B.T.H.)
| | | | - Tine Alkjær
- Department of Biomedical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark;
- The Parker Institute, Bispebjerg and Frederiksberg Hospital, 2000 Frederiksberg, Denmark
| | - Jesper Bencke
- Human Movement Analysis Laboratory, Amager-Hvidovre Hospital, 2650 Hvidovre, Denmark;
| | - Lars L. Andersen
- National Research Centre for Working Environment, 2100 Copenhagen Ø, Denmark;
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Abboud J, Daneau C, Nougarou F, Dugas C, Descarreaux M. Motor adaptations to trunk perturbation: effects of experimental back pain and spinal tissue creep. J Neurophysiol 2018; 120:1591-1601. [PMID: 29975166 DOI: 10.1152/jn.00207.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
In complex anatomical systems, such as the trunk, motor control theories suggest that many motor solutions can be implemented to achieve a similar goal. Although reflex mechanisms act as a stabilizer of the spine, how the central nervous system uses trunk redundancy to adapt neuromuscular responses under the influence of external perturbations, such as experimental pain or spinal tissue creep, is still unclear. The aim of this study was to identify and characterize trunk neuromuscular adaptations in response to unexpected trunk perturbations under the influence of spinal tissue creep and experimental back pain. Healthy participants experienced a repetition of sudden external trunk perturbations in two protocols: 1) 15 perturbations before and after a spinal tissue creep protocol and 2) 15 perturbations with and without experimental back pain. Trunk neuromuscular adaptations were measured by using high-density electromyography to record erector spinae muscle activity recruitment patterns and a motion analysis system. Muscle activity reflex attenuation was found across unexpected trunk perturbation trials under the influence of creep and pain. A similar area of muscle activity distribution was observed with or without back pain as well as before and after creep. No change of trunk kinematics was observed. We conclude that although under normal circumstances muscle activity adaptation occurs throughout the same perturbations, a reset of the adaptation process is present when experiencing a new perturbation such as experimental pain or creep. However, participants are still able to attenuate reflex responses under these conditions by using variable recruitment patterns of back muscles. NEW & NOTEWORTHY The present study characterizes, for the first time, trunk motor adaptations with high-density surface electromyography when the spinal system is challenged by a series of unexpected perturbations. We propose that the central nervous system is able to adapt neuromuscular responses by using a variable recruitment pattern of back muscles to maximize the motor performance, even under the influence of pain or when the passive structures of the spine are altered.
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Affiliation(s)
- Jacques Abboud
- Department of Anatomy, Université du Québec à Trois-Rivières , Trois-Rivières, Quebec , Canada
| | - Catherine Daneau
- Department of Human Kinetics, Université du Québec à Trois-Rivières , Trois-Rivières, Quebec , Canada
| | - François Nougarou
- Department of Electrical Engineering, Université du Québec à Trois-Rivières , Trois-Rivières, Quebec , Canada
| | - Claude Dugas
- Department of Human Kinetics, Université du Québec à Trois-Rivières , Trois-Rivières, Quebec , Canada
| | - Martin Descarreaux
- Department of Human Kinetics, Université du Québec à Trois-Rivières , Trois-Rivières, Quebec , Canada
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Abboud J, Nougarou F, Lardon A, Dugas C, Descarreaux M. Influence of Lumbar Muscle Fatigue on Trunk Adaptations during Sudden External Perturbations. Front Hum Neurosci 2016; 10:576. [PMID: 27895569 PMCID: PMC5107576 DOI: 10.3389/fnhum.2016.00576] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 11/01/2016] [Indexed: 12/12/2022] Open
Abstract
Introduction: When the spine is subjected to perturbations, neuromuscular responses such as reflex muscle contractions contribute to the overall balance control and spinal stabilization mechanisms. These responses are influenced by muscle fatigue, which has been shown to trigger changes in muscle recruitment patterns. Neuromuscular adaptations, e.g., attenuation of reflex activation and/or postural oscillations following repeated unexpected external perturbations, have also been described. However, the characterization of these adaptations still remains unclear. Using high-density electromyography (EMG) may help understand how the nervous system chooses to deal with an unknown perturbation in different physiological and/or mechanical perturbation environments. Aim: To characterize trunk neuromuscular adaptations following repeated sudden external perturbations after a back muscle fatigue task using high-density EMG. Methods: Twenty-five healthy participants experienced a series of 15 sudden external perturbations before and after back muscle fatigue. Erector spinae muscle activity was recorded using high-density EMG. Trunk kinematics during perturbation trials were collected using a 3-D motion analysis system. A two-way repeated measure ANOVA was conducted to assess: (1) the adaptation effect across trials; (2) the fatigue effect; and (3) the interaction effect (fatigue × adaptation) for the baseline activity, the reflex latency, the reflex peak and trunk kinematic variables (flexion angle, velocity and time to peak velocity). Muscle activity spatial distribution before and following the fatigue task was also compared using t-tests for dependent samples. Results: An attenuation of muscle reflex peak was observed across perturbation trials before the fatigue task, but not after. The spatial distribution of muscle activity was significantly higher before the fatigue task compared to post-fatigue trials. Baseline activity showed a trend to higher values after muscle fatigue, as well as reduction through perturbation trials. Main effects of fatigue and adaptation were found for time to peak velocity. No adaptation nor fatigue effect were identified for reflex latency, flexion angle or trunk velocity. Conclusion: The results show that muscle fatigue leads to reduced spatial distribution of back muscle activity and suggest a limited ability to use across-trial redundancy to adapt EMG reflex peak and optimize spinal stabilization using retroactive control.
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Affiliation(s)
- Jacques Abboud
- Département d'Anatomie, Université du Québec à Trois-Rivières Trois-Rivières, QC, Canada
| | - François Nougarou
- Département de Génie Électrique, Université du Québec à Trois-Rivières Trois-Rivières, QC, Canada
| | - Arnaud Lardon
- Institut Franco-Européen de ChiropraxieIvry-Sur-Seine, France; Département des Sciences de l'Activité Physique, Université du Québec à Trois-RivièresTrois-Rivières, QC, Canada
| | - Claude Dugas
- Département des Sciences de l'Activité Physique, Université du Québec à Trois-Rivières Trois-Rivières, QC, Canada
| | - Martin Descarreaux
- Département des Sciences de l'Activité Physique, Université du Québec à Trois-Rivières Trois-Rivières, QC, Canada
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Aizawa J, Ohji S, Koga H, Masuda T, Yagishita K. Correlations between sagittal plane kinematics and landing impact force during single-leg lateral jump-landings. J Phys Ther Sci 2016; 28:2316-21. [PMID: 27630422 PMCID: PMC5011586 DOI: 10.1589/jpts.28.2316] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/14/2016] [Indexed: 01/14/2023] Open
Abstract
[Purpose] The correlations of peak vertical ground reaction force and sagittal angles during single-leg lateral jump-landing with noncontact anterior cruciate ligament injury remain unknown. This study aimed to clarify the correlations between kinematics and impact force during lateral jump-landing. [Subjects and Methods] Twenty active males were included in the analysis. A sagittal-view movie camera and force plate were time synchronized. Trunk and lower extremity sagittal angles were measured 100 ms before initial contact and at peak vertical ground reaction force. Peak vertical ground reaction force, time between initial contact and peak vertical ground reaction force, and loading rate were calculated. [Results] The mean sagittal angle was 40.7° ± 7.7° for knee flexion during the flight phase and 16.4° ± 6.3° for pelvic anterior inclination during the landing phase. The mean peak vertical ground reaction force was four times the body weight. The median time to peak vertical ground reaction force was 63.8 ms. The knee flexion during the flight phase and pelvic anterior inclination angles during the landing phase were related to the peak vertical ground reaction force. [Conclusion] Increasing knee flexion and decreasing pelvic anterior inclination might reduce the impact during single-leg lateral jump-landing.
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Affiliation(s)
- Junya Aizawa
- Clinical Center for Sports Medicine and Sports Dentistry, Tokyo Medical and Dental University, Japan
| | - Shunsuke Ohji
- Clinical Center for Sports Medicine and Sports Dentistry, Tokyo Medical and Dental University, Japan
| | - Hideyuki Koga
- Joint Surgery and Sports Medicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Japan
| | - Tadashi Masuda
- Department of Symbiotic Systems Science, Fukushima University, Japan
| | - Kazuyoshi Yagishita
- Clinical Center for Sports Medicine and Sports Dentistry, Tokyo Medical and Dental University, Japan
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Maaswinkel E, Griffioen M, Perez R, van Dieën J. Methods for assessment of trunk stabilization, a systematic review. J Electromyogr Kinesiol 2016; 26:18-35. [DOI: 10.1016/j.jelekin.2015.12.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 12/03/2015] [Accepted: 12/20/2015] [Indexed: 11/27/2022] Open
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Effects of Fourteen-Day Bed Rest on Trunk Stabilizing Functions in Aging Adults. BIOMED RESEARCH INTERNATIONAL 2015; 2015:309386. [PMID: 26601104 PMCID: PMC4637013 DOI: 10.1155/2015/309386] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 06/15/2015] [Accepted: 07/01/2015] [Indexed: 01/29/2023]
Abstract
Bed rest has been shown to have detrimental effects on structural and functional characteristics of the trunk muscles, possibly affecting trunk and spinal stability. This is especially important in populations such as aging adults with often altered trunk stabilizing functions. This study examined the effects of a fourteen-day bed rest on anticipatory postural adjustments and postural reflex responses of the abdominal wall and back muscles in sixteen adult men. Postural activation of trunk muscles was measured using voluntary quick arm movement and sudden arm loading paradigm. Measurements were conducted prior to the bed rest, immediately after, and fourteen days after the bed rest. Immediately after the bed rest, latencies of anticipatory postural adjustments showed significant shortening, especially for the obliquus internus and externus muscles. After a fourteen-day recuperation period, anticipatory postural adjustments reached a near to complete recovery. On the contrary, reactive response latencies increased from pre-bed-rest to both post-bed-rest measurement sessions. Results indicate an important effect of bed rest on stabilizing functions of the trunk muscles in elderly adults. Moreover, there proved to be a significant deterioration of postural reactive responses that outlasted the 14-day post-bed-rest rehabilitation.
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Voglar M, Sarabon N. Reflex delays of the trunk muscles in response to postural perturbations: A reliability study. J Biomech 2014; 47:2807-12. [DOI: 10.1016/j.jbiomech.2014.05.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 05/29/2014] [Accepted: 05/30/2014] [Indexed: 10/25/2022]
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Shenoy S, Balachander H, Sandhu JS. Effect of Prior Instructions on Preprogrammed Reactions of Trunk Muscles in Individuals with and without Chronic Low Back Pain. NEUROPHYSIOLOGY+ 2014. [DOI: 10.1007/s11062-014-9407-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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The effects of core muscle activation on dynamic trunk position and knee abduction moments: Implications for ACL injury. J Biomech 2013; 46:2236-41. [DOI: 10.1016/j.jbiomech.2013.06.021] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 06/19/2013] [Accepted: 06/20/2013] [Indexed: 01/14/2023]
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Santos BR, Larivière C, Delisle A, McFadden D, Plamondon A, Imbeau D. Sudden loading perturbation to determine the reflex response of different back muscles: A reliability study. Muscle Nerve 2011; 43:348-59. [DOI: 10.1002/mus.21870] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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BORGHUIS ARENDJAN, LEMMINK KOENAPM, HOF ATL. Core Muscle Response Times and Postural Reactions in Soccer Players and Nonplayers. Med Sci Sports Exerc 2011; 43:108-14. [DOI: 10.1249/mss.0b013e3181e93492] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ballantyne BT, Shields RK. Quadriceps fatigue alters human muscle performance during a novel weight bearing task. Med Sci Sports Exerc 2010; 42:1712-22. [PMID: 20164810 DOI: 10.1249/mss.0b013e3181d85527] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
UNLABELLED Limited information is currently available regarding muscle synergistic patterns and triggered reflex responses during dynamic weight-bearing activities in the presence of muscle fatigue. PURPOSE The purpose of this study was to examine the effects of quadriceps muscle fatigue on patterns of muscle activation and performance in response to sudden, unexpected perturbations during a weight-bearing task. METHODS Motion of the knee was measured as subjects were asked to track a visual target as accurately as possible while performing a resisted single leg squat task. Random perturbations were delivered in 20% of the trials by unexpectedly releasing the resistance during the flexion phase of the exercise. Absolute and constant errors were calculated to evaluate target tracking performance. Quadriceps and hamstring muscle activity was recorded during both perturbed and unperturbed trials. Twelve healthy women were tested before and after completing a repetitive submaximal eccentric quadriceps fatigue protocol. A second group of 12 women served as controls. Unexpected perturbations elicited long-latency responses characterized by facilitation of the quadriceps and inhibition of the hamstrings. RESULTS Muscle fatigue increased the amplitude of the long-latency response in vastus lateralis by 4.3% maximum voluntary isometric contraction (P = 0.004). Changes in tracking error occurred in response to perturbations after fatigue in spite of significantly increased quadriceps muscle activity, especially during the extension phase of the exercise. CONCLUSION Quadriceps muscle fatigue alters the patterns of coordinated muscle activity and may render subjects less able to cope with unexpected perturbations during weight-bearing tasks.
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Affiliation(s)
- Bryon T Ballantyne
- Graduate Program in Physical Therapy and Rehabilitation Science, The University of Iowa, Iowa City, IA 52242, USA
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Krustrup P, Hansen PR, Andersen LJ, Jakobsen MD, Sundstrup E, Randers MB, Christiansen L, Helge EW, Pedersen MT, Søgaard P, Junge A, Dvorak J, Aagaard P, Bangsbo J. Long-term musculoskeletal and cardiac health effects of recreational football and running for premenopausal women. Scand J Med Sci Sports 2010; 20 Suppl 1:58-71. [PMID: 20546545 DOI: 10.1111/j.1600-0838.2010.01111.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We examined long-term musculoskeletal and cardiac adaptations elicited by recreational football (FG, n=9) and running (RG, n=10) in untrained premenopausal women in comparison with a control group (CG, n=9). Training was performed for 16 months ( approximately 2 weekly 1-h sessions). For FG, right and left ventricular end-diastolic diameters were increased by 24% and 5% (P<0.05), respectively, after 16 months. Right ventricular systolic function measured by tricuspid annular plane systolic excursion (TAPSE) increased (P<0.05) in FG after 4 months and further (P<0.05) after 16 months (15% and 32%, respectively). In RG and CG, cardiac structure, E/A and TAPSE remained unchanged. For FG, whole-body bone mineral density (BMD) was 2.3% and 1.3% higher (P<0.05) after 16 months, than after 4 and 0 months, respectively, with no changes for RG and CG. FG demonstrated substantial improvements (P<0.05) in fast (27% and 16%) and slow (16% and 17%) eccentric muscle strength and rapid force capacity (Imp30ms: 66% and 65%) after 16 months compared with 4 and 0 months, with RG improving Imp30ms by 64% and 46%. In conclusion, long-term recreational football improved muscle function, postural balance and BMD in adult women with a potential favorable influence on the risk of falls and fractures. Moreover, football training induced consistent cardiac adaptations, which may have implications for long-term cardiovascular health.
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Affiliation(s)
- P Krustrup
- Department of Exercise and Sport Sciences, Section of Human Physiology, University of Copenhagen, Copenhagen, Denmark.
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Pedersen MT, Randers MB, Skotte JH, Krustrup P. Recreational Soccer Can Improve the Reflex Response to Sudden Trunk Loading Among Untrained Women. J Strength Cond Res 2009; 23:2621-6. [DOI: 10.1519/jsc.0b013e3181c701b6] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Changes in physical performance among construction workers during extended workweeks with 12-hour workdays. Int Arch Occup Environ Health 2009; 83:1-8. [PMID: 19859728 DOI: 10.1007/s00420-009-0471-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Accepted: 10/04/2009] [Indexed: 10/20/2022]
Abstract
PURPOSE To investigate changes of physical performance during long working hours and extended workweeks among construction workers with temporary accommodation in camps. METHODS Nineteen construction workers with 12-h workdays and extended workweeks participated. Physical performance in the morning and evening of the second and eleventh workdays was tested by endurance, ability to react to a sudden load, flexibility of the back, handgrip strength and sub-maximal HR during a bicycle test. HR was registered throughout two separate workdays. RESULTS HR during each of the two separate workdays corresponded to a relative workload of 25%. Sub-maximal HR was lower, reaction time faster and handgrip strength higher in the end of each test day. In the end of the work period, sub-maximal HR was lower, reaction time faster and sitting balance was better. CONCLUSION No trends of decreased physical performance were found after a workday or a work period.
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Pedersen MT, Essendrop M, Skotte JH, Jørgensen K, Schibye B, Fallentin N. Back muscle response to sudden trunk loading can be modified by training among healthcare workers. Spine (Phila Pa 1976) 2007; 32:1454-60. [PMID: 17545916 DOI: 10.1097/brs.0b013e318060a5a7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Experimental study of the effect of physical training on the reaction to sudden back loading. OBJECTIVE To investigate the effect and sustainability of "on the job training" on the reaction to sudden back loading among employees at a geriatric ward. SUMMARY OF BACKGROUND DATA Available data suggest that a delayed muscle reflex response to sudden trunk loading may increase the risk of low back injuries. We have previously shown that training may alter the response to sudden trunk loading in healthy subjects and decrease the time elapsed until stopping of the forward movement of the trunk (stopping time). Data on the possibilities of a training-induced improvement in the reflex response among workers exposed to sudden trunk loading on the job are, however, nonexistent, and there is no evidence of long-term benefits, i.e., the sustainability of a positive training effect. METHODS The study included 23 participants and 14 controls. All were healthy without prior history of low back pain (LBP). The training group participated in a total of 18 training sessions during a 9-week period. The training focused on reactions to a variety of sudden trunk loadings. Before and after the training intervention and at a 1-year follow-up, all subjects were tested for their reaction to expected and unexpected sudden trunk loading by applying a horizontal force of 58 N to the upper back of the subjects and measuring the electromyographic (EMG) response from the erector spinae muscles. RESULTS In the training group, the stopping time and the distance moved after unexpected sudden trunk loading decreased significantly (13%-19%, P = 0.02). The improved stopping time was associated with marked changes in the time-wise distribution of the EMG signal after training. In addition, the follow-up study showed a high sustainability of the training effect. CONCLUSIONS The results demonstrated a training-induced improvement of the response to sudden trunk loading that may be beneficial in workers, such as nurses, who are exposed to sudden trunk perturbations during patient handling.
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Drake JDM, Callaghan JP. Elimination of electrocardiogram contamination from electromyogram signals: An evaluation of currently used removal techniques. J Electromyogr Kinesiol 2006; 16:175-87. [PMID: 16139521 DOI: 10.1016/j.jelekin.2005.07.003] [Citation(s) in RCA: 232] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2004] [Revised: 04/01/2005] [Accepted: 07/01/2005] [Indexed: 11/15/2022] Open
Abstract
Trunk electromyographic signals (EMG) are often contaminated with heart muscle electrical activity (ECG) due to the proximity of the collection sites to the heart and the volume conduction characteristics of the ECG through the torso. Few studies have quantified ECG removal techniques relative to an uncontaminated EMG signal (gold standard or criterion measure), or made direct comparisons between different methods for a given set of data. Understanding the impacts of both untreated contaminated EMG and ECG elimination techniques on the amplitude and frequency parameters is vital given the widespread use of EMG. The purpose of this study was to evaluate four groups of current and commonly used techniques for the removal of ECG contamination from EMG signals. ECG recordings at two intensity levels (rest and 50% maximum predicted heart rate) were superimposed on 11 uncontaminated biceps brachii EMG signals (rest, 7 isometric and 3 isoinertial levels). The 23 removal methods used were high pass digital filtering (finite impulse response (FIR) using a Hamming window, and fourth-order Butterworth (BW) filter) at five cutoff frequencies (20, 30, 40, 50, and 60 Hz), template techniques (template subtraction and an amplitude gating template), combinations of the subtraction template and high pass digital filtering, and a frequency subtraction/signal reconstruction method. For muscle activation levels between 10% and 25% of maximum voluntary contraction, the template subtraction and BW filter with a 30 Hz cutoff were the two best methods for maximal ECG removal with minimal EMG distortion. The BW filter with a 30 Hz cutoff provided the optimal balance between ease of implementation, time investment, and performance across all contractions and heart rate levels for the EMG levels evaluated in this study.
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Affiliation(s)
- Janessa D M Drake
- Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ont., Canada N2L 3G1
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Hjortskov N, Essendrop M, Skotte J, Fallentin N. The effect of delayed-onset muscle soreness on stretch reflexes in human low back muscles. Scand J Med Sci Sports 2006; 15:409-15. [PMID: 16293153 DOI: 10.1111/j.1600-0838.2004.00438.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The aim of the study was to investigate the effect of moderate delayed-onset muscle soreness (DOMS) on the short latency stretch reflex (SLR) and long latency stretch reflex (LLR) response i.e. electromyographic (EMG) onset latencies and EMG amplitudes in erector spinae (ES). Nine males with muscle soreness (DOMS group) were tested 24, 48 h, and 7 days post-exercise. Eight males (control group) were tested likewise. EMG was measured from ES bilaterally at the level of L3/L4. The SLR was elicited by mechanically tapping the ES at L3/L4, and the LLR was elicited by sudden loadings of the spine. Significant reductions in force during maximal voluntary contractions and range of motion, and a significant increase in muscle soreness (measured by pressure algometry) and subjective experience of soreness in the low back indicated DOMS 24, and 48 h post-exercise in the DOMS group. No changes were observed in the control group. The SLR and LLR response were unaffected by DOMS, i.e. no changes in EMG latencies and amplitudes were observed. In conclusion, despite changes in DOMS indicators, the reflex system protecting the stability of the lumbar spine is apparently capable of maintaining an appropriate triggering of SLR and LLR.
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Affiliation(s)
- N Hjortskov
- National Institute of Occupational Health, Department of Physiology, Copenhagen, Denmark.
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Skotte J, Hjortskov N, Essendrop M, Schibye B, Fallentin N. Short latency stretch reflex in human lumbar paraspinal muscles. J Neurosci Methods 2005; 145:145-50. [PMID: 15922032 DOI: 10.1016/j.jneumeth.2004.12.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2004] [Revised: 11/25/2004] [Accepted: 12/16/2004] [Indexed: 11/28/2022]
Abstract
The aim of the study was to measure stretch reflex latencies of the lumbar paraspinal muscles. An electromechanical tapping system was constructed enabling an accurate estimation of short latencies by utilizing a new technique combining results for different tapping durations. Latency parameters (onset, peak and zero-crossing of EMG signal) were obtained for the paraspinal muscles at the L3/L4 level for 10 male subjects. Detection of EMG onset, which was determined by a threshold criterion (2.5 S.D. of pre-activity), yielded 7.4+/-1.4 ms corresponding to a physiological short latency onset of 6.5 ms, which is considerably shorter than previously reported. However, it is shown to be consistent with the expected latency value for a monosynaptic stretch reflex for the paraspinal muscles of the low back.
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Affiliation(s)
- Jørgen Skotte
- Department of Physiology, National Institute of Occupational Health, Lersø Parkallé 105, DK-2100 Copenhagen, Denmark.
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