What Are We Aiming for in Eccentric Hamstring Training: Angle-Specific Control or Supramaximal Stimulus?

Tobias Alt, Axel Knicker, Yannick Nodler, Heiko Klaus Strüder

Publication: Contribution to journalJournal articlesResearchpeer-review

Abstract

Different resistance exercise determinants modulate the musculotendinous adaptations following eccentric hamstring training. The Nordic Hamstring Exercise (NHE) can be performed 2-fold: the movement velocity irreversibly increases toward the end of the range of motion or it is kept constant. Design: This cross-sectional study aimed to investigate if the downward acceleration angle (DWAangle) can be used as a classification parameter to distinguish between increasing and constant velocity NHE execution. Furthermore, the kinetic and kinematic differences of these 2 NHE execution conditions were examined by analyzing the DWAangle in relation to the angle of peak moment. Methods: A total of 613 unassisted NHE repetitions of 12 trained male sprinters (22 y, 181 cm, 76 kg) were analyzed. Results: The majority of analyzed parameters demonstrated large effects. NHEs with constant velocity (n = 285) revealed significantly higher impulses (P < .001; d = 2.34; + 61%) and fractional time under tension (P < .001; d = 1.29; +143%). Although the generated peak
moments were significantly higher for constant velocity (P = .003; d = 0.29; +4%), they emerged at similar knee flexion angles (P = .167; d = 0.28) and revealed on average just low relationships to the DWAangle (R2mean = 22.4%). DWAangle highly correlated with the impulse (R2mean = 60.8%) and δ (DWAangle–angle of peak moment; R2mean = 83.6%). Conclusions: Relating DWAangle to angle of peak moment assists to distinguish between significantly different NHE execution, which will potentially elicit different musculotendinous adaptations. These insights are essential for coaches and athletes to understand how to manipulate eccentric hamstring training to change its purpose.
Keypoints
• The downward acceleration angle (DWAangle) can be used as a classification parameter to distinguish between increasing (vinc) and constant velocity (vcon) Nordic Hamstring Exercise (NHE) execution.

• Constant velocity NHEs revealed 61% higher impulses and 143% longer fractional time under tension (TUT < 45° knee flexion) than increasing velocity executions.

• Peak moments were 4% higher for vcon NHEs but occurred at similar knee flexion angles.
• Both NHE execution conditions demonstrated substantially different kinematics and kinetics, which will affect the subsequent musculotendinous adaptations.

Original languageEnglish
JournalJournal of sport rehabilitation
Pages (from-to)1-8
Number of pages8
DOIs
Publication statusPublished - 2023

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