Biomechanical factors associated with previous hamstring injury in high level sprinting athletes
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Hamstring injury is common in sprinting sports and injury recurrence remains a major concern. The aim of this thesis is to explore the biomechanical characteristics of athletes following sprint related hamstring injury. We conducted 1) An examination of already published research on biomechanical deficits following hamstring injury in athletes who had returned to sport by means of a systematic review and meta-analysis; 2) A detailed examination of sprinting following hamstring injury in athletes who had returned to sport muscle activity using 3D motion capture and surface EMG; 3) An examination of high intensity eccentric loading performance in previously injured athletes using low density, high surface area surface EMG and measures of force; 4) An analysis of hamstring muscle recovery until return to sport following hamstring injury using low density, high surface area surface EMG and measures of force via case reports in two elite athletes. Previous research indicates that athletes who had returned to sport following hamstring injury continue to display deficits in force production, especially during slow eccentric contractions. The observational studies indicate that athletes run with significantly asymmetric movements about the pelvis and hip that would place their hamstrings under increased length during the terminal swing phase of sprinting. Furthermore, significant alterations in late swing EMG ratios suggest relatively reduced activity in the previously injured biceps femoris. Spatial activation of the hamstring appears altered in previously injured athletes, with reduced relative activation of the proximal muscle and reduced median frequency values in the medial muscle compared to control limbs. Asymmetries in activation patterns are also noted in the pre-return to sport phase. Previous hamstring injury is associated with significant alterations in force production, movement symmetry and muscle activation patterns following return to sport highlighting the complexity of this injury and the need for advanced rehabilitation screening approaches.
- Theses