Optimizing Hamstring Activation Through EMG-Feedback and the Hamshell Device

Hamstring injuries represent a significant burden in both recreational and competitive sports. Conventional hamstring training programmes primarily target muscle strength and hypertrophy. Despite generally positive outcomes, individual responses to strength-focused interventions vary considerably, suggesting that improvements in strength alone may not fully account for reductions in injury risk. Neuromuscular control and movement quality - factors likely relevant to hamstring injury risk - are not explicitly addressed in most traditional training protocols.

The Nordic hamstring exercise (NHE) is frequently used in clinical and sports practice, but presents biomechanical limitations, particularly with regard to loading at extended knee angles. The Hamshell device has been developed to address these limitations by enabling hamstring-specific loading across a broader range of knee angles.

Electromyographic (EMG) biofeedback is a technique in which real-time information about muscle electrical activity is provided to the user during exercise. This approach has been shown to enhance voluntary muscle activation and neuromuscular control in various rehabilitation and training contexts. Combining EMG biofeedback with Hamshell-based training may therefore optimise neuromuscular adaptations beyond what can be achieved with resistance training alone.

Study Design

This is a single-centre, prospective, randomised controlled intervention study with a parallel-group design, conducted at the Praxisklinik Rennbahn AG in Muttenz, Switzerland.