The Effect of Ankle Position on Peak Eccentric Force during The Nordic Hamstring Exercise.

Area of Science:

• Sports Medicine
• Biomechanics
• Exercise Physiology

Background:

• Peak eccentric force during the Nordic hamstring exercise (NHE) is a key predictor of hamstring strain injury (HSI).
• The gastrocnemius muscle's action, influenced by ankle position, is hypothesized to affect peak eccentric force during NHE.
• The precise impact of ankle position on NHE peak eccentric force remains inadequately understood.

Purpose of the Study:

• To investigate the influence of ankle position (dorsiflexed vs. plantarflexed) on peak eccentric force during the NHE.
• To provide data that can inform injury prevention strategies and training protocols for hamstring injuries.

Main Methods:

• Fifty healthy young male rugby players with no prior HSI history participated.
• Participants performed NHE strength testing in both dorsiflexed and plantarflexed ankle positions.
• Peak eccentric force, normalized to body mass (N/kg), was measured for both legs and averaged.

Main Results:

• Mean peak eccentric force was significantly greater in the plantarflexed ankle position (3.8 ± 1.1 N/kg) compared to the dorsiflexed position (3.5 ± 1.1 N/kg).
• The difference in peak eccentric force between ankle positions was statistically significant (p = 0.049).

Conclusions:

• Ankle position significantly affects peak eccentric force during the NHE.
• Consideration of ankle positioning is essential for accurate NHE strength assessment and effective NHE training to mitigate HSI risk.