Hamstring strain injuries: Risk factors and evaluation of a training programme

Project Number
RI 4/15 KPW

Project Duration
April 2016 - March 2019

Status
In-Progress

Abstract
Hamstring strain injuries (HSI) are common sports injuries that involve repeated maximal jumping, sprinting and turning movements (e.g. football, rugby, hockey). The long recovery time associated with HSI translates into a substantial amount of time loss in sport that affects both recreational and elite players. The main objectives of this project are 1) to examine the muscle architecture and functional risk factors of HSI, and 2) to evaluate the influence of a hamstring training programme on HSI risk factors. A series of two studies are proposed. In Study 1, comparisons would be made between previously injured and uninjured athletes in order to identify muscle architecture and functional risk factors of HSI. Forty male athletes will be recruited (20 previously injured, 20 uninjured). Muscle viscoelastic properties (e.g. stiffness) will be assessed using myotonometry, whereas muscle architecture (e.g. pennation angle, fascial length) variables determined from sonography. For functional assessments, muscle strength will be measured using isokinetic dynamometry while muscle activation will be monitored using electromyography (EMG). In addition, the running biomechanics will be assessed using motion analysis in synchronisation with EMG. Comparisons of architecture and functional measures, as well as running biomechanics, will be made between previously injured and uninjured athletes. Study 2 comprises two sub-phases. Study 2a aims to identify the best out of 5 commonly practised hamstring training exercises to be used in a subsequent intervention study. Twenty active male athletes will perform five hamstring training exercises administered in a randomised manner: (i) hamstring curl using resistance band, (ii) hamstring curl on resistance machine, (iii) Nordic hamstring exercise, (iv) “good morning” exercise, and (v) bridge. Muscle activation will be measured via EMG coupled with motion analysis. After the most suitable exercise has been identified, Study 2b will evaluate the influence of a hamstring training programme on HSI risk factors. In this phase, 30 male active athletes (15 in experimental group, 15 in control group) would undergo a 16-week structured hamstring training programme. During the intervention period, the experimental group will undergo supervised training three times per week using the most effect hamstring training exercise identified in Study 2a. Pre- and post-training measures of muscle architecture and functional variables would be assessed to track the effectiveness of the intervention. Findings from these studies will improve the limited understanding of HSI risk factors and guide future development of preventive and rehabilitative strategies.

Funding Source
NIE

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