Voluntary Activation and Reflex Responses after Hamstring Strain Injury

Robert L Buhmann; Gabriel Trajana; Graham Kerr; Anthony Shield

doi:10.1249/MSS.0000000000002327

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Voluntary Activation and Reflex Responses after Hamstring Strain Injury

Journal article

Open access

Peer reviewed

Voluntary Activation and Reflex Responses after Hamstring Strain Injury

Robert L Buhmann, Gabriel Trajana, Graham Kerr and Anthony Shield

Medicine and Science in Sports and Exercise, Vol.52(9), pp.1862-1869

2020

DOI: https://doi.org/10.1249/MSS.0000000000002327

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Abstract

Introduction: There is a lack of definitive evidence supporting deficits in voluntary activation in participants with prior hamstring injury, moreover it remains unknown if spinal mechanisms contribute to suspected deficits. Purpose : To determine the effect of prior hamstring strain injury on knee flexor concentric and eccentric strength, voluntary activation, surface electromyographic activity (sEMG), stretch and tendon reflex amplitudes. Methods : Twenty-five participants were recruited, twelve with a history of unilateral hamstring strain injury of at least moderate severity. Voluntary activation, strength and sEMG activity were recorded during maximal eccentric and concentric knee flexor contractions at 60°/s. Stretch and tendon reflexes were also recorded at rest. Results : Previously injured limbs exhibited lower levels of voluntary activation (mean difference= -24.1% [95% CI = -34.1 to -14.0%], p&0.001) strength (mean difference vs. control group = -0.37 Nm/kg [95%CI = -0.71 to -0.03 Nm/kg], p = 0.03) and normalised sEMG (mean difference = -17% [95% CI = -32 to -2%], p = 0.02) during maximal eccentric knee flexor contractions compared to control group. No such differences were seen in concentric contractions. Stretch reflexes (mean difference = -3.8% [95% CI = -6.8 to -0.8], p = 0.02) and tendon reflexes (mean difference = -13% [95%CI = -26 to 0%], p = 0.04) were also lower in previously injured compared to control biceps femoris muscles. Conclusion : Moderate to severe hamstring strain injury is associated with long-term deficits in voluntary activation during maximal eccentric contraction. Hamstring injury history is also associated with deficits in stretch reflex and tendon reflex amplitude.

Details

Title: Voluntary Activation and Reflex Responses after Hamstring Strain Injury
Authors: Robert L Buhmann (Author) - University of the Sunshine Coast - School of Health and Sport Sciences
Gabriel Trajana (Author) - Queensland University of Technology
Graham Kerr (Author) - Queensland University of Technology
Anthony Shield (Author) - Queensland University of Technology
Publication details: Medicine and Science in Sports and Exercise, Vol.52(9), pp.1862-1869
Publisher: Lippincott Williams & Wilkins
Date published: 2020
DOI: 10.1249/MSS.0000000000002327
ISSN: 0195-9131
Copyright note: Copyright (c) 2020. The author's accepted version is reproduced here in accordance with the publisher's copyright policy. The definitive version is available at: https://doi.org/10.1249/MSS.0000000000002327
Organisation Unit: University of the Sunshine Coast, Queensland; School of Health and Sport Sciences - Legacy; School of Health - Sports & Exercise Science; School of Health and Behavioural Sciences - Legacy
Language: English
Record Identifier: 99450983602621
Output Type: Journal article

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Collaboration types: Domestic collaboration
Web Of Science research areas: Sport Sciences