The Effect of the Nordic Hamstring Exercise on Hamstring Muscle Activity Distribution During High-Speed Running Estimated Using Multichannel Electromyography: A Pragmatic Randomized Controlled Trial.

OBJECTIVE

To evaluate the effect of the Nordic hamstring exercise on normalized muscle activity and relative contribution of the biceps femoris long head, semitendinosus, and semimembranosus through multichannel electromyography in the late-swing phase of high-speed running.

DESIGN

A pragmatic, 2-arm, single-center randomized controlled trial. Participants were randomly assigned to a Nordic group or control group.

SETTING

Dutch male basketball.

PARTICIPANTS

Twenty injury-free players (mean age 18 ± 3 years).

INTERVENTION: A 12-week Nordic hamstring exercise intervention.

MAIN OUTCOME MEASURES: Level of normalized muscle activity (percentage maximal voluntary isometric contraction [%MVIC]) and relative contribution (%con) of hamstring muscles for 12 weeks.

RESULTS

The Nordic hamstring exercise intervention did not result in significant changes for 12 weeks. For normalized muscle activity, between-group differences (compared with the control group) for 12 weeks were 11.4 %MVIC (95% confidence interval [95% CI]: -11.0, 33.8) for the biceps femoris long head, -9.4 %MVIC (95% CI: -23.3, 5.2) for the semitendinosus, and -2.7 %MVIC (95% CI: -15.8, 10.3) for the semimembranosus, P = 0.151. For relative contribution, between-group differences for 12 weeks were -6.1 %con (95% CI: -2.4, 14.6) for the biceps femoris long head, -7.0 %con (95% CI: -13.6, -0.4) for the semitendinosus, and 0.9 %con (95% CI: -9.2, 11.0) for the semimembranosus P = 0.187. Positive values are in favor of the Nordic group.

CONCLUSIONS

A 12-week Nordic hamstring exercise intervention did not affect the level of muscle activity and relative contribution of hamstring muscles in the late-swing phase of high-speed running. Because of the low amount of data sets, results should be interpreted cautiously.