Effect of different slopes of the lower leg during the nordic hamstring exercise on hamstring electromyography activity

Toshiaki Soga, Daichi Nishiumi, Atsuya Furusho, Kei Akiyama, Norikazu Hirose

Research output: Contribution to journalArticlepeer-review

Abstract

The purpose of this study was to examine whether the NHE with an increased lower leg slope angle would enhance hamstring EMG activity in the final phase of the descend. The hamstring EMG activity was measured, the biceps femoris long head (BFlh) and the semitendinosus (ST). Fifteen male volunteers participated in this study. Subjects performed a prone leg curl with maximal voluntary isometric contraction to normalize the hamstring EMG activity. Subsequently, subjects performed the NHE, with the help of a certified strength and conditioning specialist, while the lower leg slope angle were randomly set at 0° (NH), 20° (N20), and 40° (N40). To compare hamstring EMG activity during the NHE variations, the knee flexion angle was set in the range from 0° to 50°, divided into five phases (0–10°, 10–20°, 20–30°, 30– 40° and 40–50°), where 0° indicated that the knee was fully ex-tended. To calculate the knee extension angular velocity, the knee flexion angle divided by time, and break point angle (BPA) was the angle at which 10°/s was exceeded. In the statistical analysis, a two-way repeated measures ANOVA was used for the hamstring EMG activity and a one-way repeated measures ANOVA was used for the BPA. The EMG activity of the BFlh and the ST in N20 and N40 was significantly higher than in NH at knee flexion angle of 0–20° (p < 0.05). For the BPA, NH (57.75° ± 13.28°), N20 (36.27° ± 9.89°) and N40 (16.26° ± 9.58°) were significantly higher in that order (p < 0.05). The results of this study revealed that the NHE with an increased lower leg slope angle shifted the BPA to the lower knee flexion angle and enhanced the hamstring EMG activity in the final phase of the descent.

Original languageEnglish
Pages (from-to)216-221
Number of pages6
JournalJournal of Sports Science and Medicine
Volume20
Issue number2
DOIs
Publication statusPublished - 2021

Keywords

  • Electromyography
  • Hamstring mus-cles
  • Injury recurrence
  • Rehabilitation exercise
  • Resistance train-ing
  • Sports injuries

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

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