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Muscle Imbalances: Testing and Training Functional Eccentric Hamstring Strength in Athletic Populations
Published on: May 1, 2018
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Individual Region- and Muscle-specific Hamstring Activity at Different Running Speeds
András Hegyi1, Basílio A M Gonçalves1,2, Taija Finni1
1Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyvaskyla, FINLAND.
Medicine and Science in Sports and Exercise
|October 22, 2019
Summary
Hamstring muscle activation patterns during running are unique to each individual but remain consistent across different speeds. This suggests that rehabilitation should focus on submaximal running speeds to restore normal neuromuscular function after hamstring injuries.
Area of Science:
- Biomechanics of human locomotion
- Muscle physiology and neuromuscular control
- Sports injury prevention and rehabilitation
Background:
- Hamstring strain injuries (HSIs) commonly affect the biceps femoris long head (BFlh), particularly at high running speeds.
- Muscle activation is a potential regulator of strain injury, but region-specific activity within the hamstring muscles during running has not been fully investigated.
Purpose of the Study:
- To examine the region-specific (proximal-distal) and intermuscular (BFlh vs. semitendinosus) activity of hamstring muscles during running at increasing speeds.
- To understand how hamstring muscle activation patterns change or remain consistent with varying running velocities.
Main Methods:
- High-density electromyography (EMG) was used to record region- and muscle-specific activity in 13 participants running at slow (4.1 m/s), moderate (5.4 m/s), and fast (6.8 m/s) speeds.
- EMG data were normalized to maximal voluntary isometric contractions, and muscle-tendon unit lengths were calculated from kinematic data.
- Statistical Parametric Mapping was employed to analyze speed effects and regional/intermuscular differences.
Main Results:
- EMG activity increased similarly across all regions of the BFlh and semitendinosus with increasing running speed, particularly during the late swing phase.
- Muscle-tendon unit length changes during late swing were minimal relative to speed increases.
- In fast running, EMG activity in the late swing phase reached high levels (e.g., 115% ± 20% in proximal BFlh relative to maximal voluntary isometric activity).
- Individual hamstring muscle activation patterns (proximal-distal and intermuscular) were consistent across different running speeds.
Conclusions:
- Running elicits highly individualized hamstring muscle activation patterns that are maintained across various speeds.
- Rehabilitation strategies for hamstring injuries should consider incorporating submaximal running speeds to facilitate the restoration of normal neuromuscular function.
