The relationship between eccentric hamstring strength and dynamic stability in elite academy footballers

Abstract

Objectives: Previous research describes dynamic stability and functional strength as key aetiological risk factors associated with lower limb non-contact musculoskeletal injury. Due to the multi factorial nature of injury risk, relationships between the two factors will inform injury management and training design.Methods: Fifty-nine elite academy footballers from two English premier league category 1-status academies completed the study. All players completed measures of eccentric hamstring strength and dynamic stability. Relationships between directional stability (Anteroposterior (Ant), Posteromedial (PM) and Posterolateral (PL)) and eccentric strength metrics (PkT, AvT, PkF, AvF and Ɵ) bilaterally were identified for analysis.Results: Significant correlations were identified bilaterally for functional hamstring strength metrics and PM and PL stability (P ≤. 0.05). No significant relationships were identified between anterior stability and eccentric hamstring strength parameters (P > 0.05). Conclusions:Eccentric hamstring strength has a positive influence on directional stability through two planes, PM and PL. The lack of influence of eccentric hamstring strength on Ant directional stability could be attributed to increased ACL risk. Careful consideration of the significance of the relationships between eccentric hamstring strength and directional stability must be given when quantifying injury risk in elite academy footballers.

Acute effects of varying densities of foam roller on hamstring flexibility and eccentric strength

“…Recent literature has identified that increases in flexibility have been associated with reductions of functional strength through range, and thus increased injury risk (Opar, 2013;Timmins et al, 2016). This body of work highlighted changes in muscle architecture as a key aetiological factor, with o representing a metric to provide insight into this factor within the present study (Greig., 2008;Rhodes et al, 2018;Rhodes et al, 2020). The present body of work identified no significant changes in functional strength metrics and break angle despite increases in flexibility.…”

Quantification of Eccentric Hamstrings Strength in Elite Academy Footballers: Considerations for Assessment

“…Reasons for this are unclear, however, it is suggested this could potentially be associated with the bilateral nature of the exercise (Opar et al, 2013;Timmins et al, 2015) and the larger group of muscle recruitment required to perform the exercise (Wiesinger et al, 2020). This may highlight deficiencies in elite youth footballers that could contribute to sustaining lower limb injury (Rhodes et al, 2020a). Practitioners and future research should consider electromyographic analysis of the musculature during performance of the test to identify asymmetry.…”

“…Each trial was recorded from the sagittal plane using a Canon XA35 camera at 50 Hz. The camera was placed on a fixed stand set 3 m away and 0.5 m from the floor (Rhodes et al, 2020a). Each participants' Ɵ (lowest, closest to the floor) was calculated by using reflective markers placed on the skin of the anatomical landmarks previously set with the best repetition used for the purpose of the research (Rhodes et al, 2020a), which included; right greater trochanter, lateral femoral condyle, and lateral malleolus (Lee, Mok, Chan, Yung, Chan, 2017).…”

“…Individual's knee position on the NordBord was recorded using the integrated knee position guides with the ankle restraints at 90°, 2 cm superior to the lateral malleolus to ensure the body position remain consistent between tests. The NHE completed on the NordBord was analysed using a variation of the motion analysis protocol adopted from previous studies (Rhodes et al, 2020a). Video clips were digitized and transformed into a two-dimensional space using motion analysis application software (IOS Nordics Application).…”

“…Quantification of eccentric hamstring strength (Ham ecc ) is an ongoing contemporary debate between academics and practitioners, due to the influence of the hamstring on knee function and the incidence of hamstring injuries within the modern game (Rhodes et al, 2020a;Chebbi, Chamari, Van Dyk, Gabbett, Tabben, 2020). Hamstring strain injuries (HSI) account for 12% of all injuries documented in professional football and represented 37% of all muscle injuries sustained (Ekstrand, Hägglund, Walden, 2011).…”