Muscle Activity and Kinematics During Three Hamstring Strengthening Exercises Compared to Sprinting: A Cross-Sectional Study.
Adelso Jorge, Eric Lichtenstein, Oliver Faude and 1 others
PMID 38707851WHAT IT FOUND
The rocker exercise produced higher hamstring muscle activity than the Nordic hamstring exercise or sprinting.
However, none of the tested exercises stretched the hamstring as much as sprinting does, which is the position where injuries typically occur.
Key findings
01The rocker exercise resulted in significantly higher peak and average hamstring muscle activity compared to the Nordic hamstring exercise, the perpetuum mobile slow, and high-speed running.
02All tested exercises demonstrated peak muscle activity at shorter hamstring lengths than sprinting, failing to reach the elongation stress associated with injury risk.
03There was no difference in the ratio of biceps femoris to semitendinosus activation between the exercises, despite the hypothesis that hip-dominant moves would target the biceps femoris more.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study included only 8 participants, all male sprint athletes, which limits generalizability. The exercises were performed on a treadmill or custom apparatus, which may not fully replicate the mechanics of overground sprinting. Surface EMG measures muscle activation, not actual force or lengthening strain, so 'elongation stress' is an estimate based on joint angles. The authors adjusted the load/resistance for each participant to ensure technical correctness, which may have altered the kinematics compared to a standardized load.
Declared interests
No specific funding sources or conflicts of interest are declared in the provided text.
The easy way to misread this
Do not assume that higher muscle activity equals better injury prevention. The study found that while the rocker activates the hamstrings more than the NHE, it does so at shorter muscle lengths. Injury prevention often requires training the muscle to tolerate force while it is being stretched, which these exercises did not replicate.