RESEARCH SUMMARY: Reduced biceps femoris myoelectrical activity influences eccentric knee flexor weakness after repeat sprint running (Timmins et al. 2014)

Title: Reduced biceps femoris myoelectrical activity influences eccentric knee flexor weakness after repeat sprint running

Author/s: Timmins, (@ryan_timmins),  Opar (@davidopar), Williams (@drmorgs), Schache, Dear, and Shield (@das_shield)

Year: 2014

Journal: Scandinavian Journal of Medicine & Science in Sports (ISSN: 1600-0838) 

Question: How does repeated sprint running affect the hamstring muscles?

Key Takeaway: Sprint running caused reductions in muscle strength, which were also consistent with reduced myoelectric activity.

Link: http://researchbank.acu.edu.au/fhs_pub/83/

Summary: Seventeen recreationally active men performed a repeated sprinting protocol with measures of maximal isokinetic strength taken before and after the running in addition to sEMG.  Significant declines in eccentric and concentric knee flexor strength were observed with eccentric biceps femoris myoelectrical activity significantly reduced as well. There were no changes to concentric biceps femoris or medial hamstring myoelectrical activity.

Key Findings: 

• Following repeat sprint running, there was a decline in eccentric knee flexor strength that was related to a significant decline in the myoelectrical activity of the biceps femoris.
• Declines in biceps femoris myoelectrical activity following repeat sprint running and its role in the aetiology of HSIs still require further attention.