Kinematic and electromyographic effects of different execution modalities during the Nordic Hamstring Exercise

Area of Science:

• Biomechanics
• Exercise Physiology
• Sports Science

Background:

• The Nordic Hamstring Exercise (NHE) is a key exercise for eccentric hamstring strengthening and preventing injuries.
• Variations in NHE execution may influence its effectiveness.

Purpose of the Study:

• To investigate how three different NHE execution modalities impact break-point angle (BPA) and hamstring muscle activation.
• To determine if higher execution quality leads to greater muscle activation and more extended BPAs.

Main Methods:

• Forty-two participants performed NHE using partner fixation, rigid heel fixation, and a specialized training device.
• Kinematic data captured break-point angles (BPAs), while surface EMG measured hamstring muscle (M. biceps femoris and M. semitendinosus) activation.
• Statistical analysis involved Friedman tests with Wilcoxon post-hoc comparisons.

Main Results:

• Significant differences in BPA were observed across modalities (p < 0.01).
• The training device resulted in the most extended knee positions (56.0° ± 13.8°), compared to partner (74.8° ± 9.4°) and rigid heel fixation (74.3° ± 11.1°).
• Higher root mean square and integrated EMG values were recorded with the training device compared to the other two modalities (p < 0.01).

Conclusions:

• NHE execution modality significantly affects movement mechanics and neuromuscular demand.
• The training device offers a more effective method for hamstring strengthening due to increased muscle activation and extended knee positioning.
• For standardized NHE testing and training, using rigid heel fixation with controlled setup conditions is recommended.