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Impact of exercise selection on hamstring muscle activation.

Matthew N Bourne1,2,3, Morgan D Williams4, David A Opar5

  • 1Faculty of Health, School of Exercise and Nutrition Science, Queensland University of Technology, Brisbane, Australia.

British Journal of Sports Medicine
|July 29, 2016
PubMed
Summary

Hip extension exercises selectively activate the biceps femoris long head (BFLongHead) muscle, while Nordic hamstring exercises preferentially recruit the semitendinosus. This research aids in hamstring injury prevention and targeted mechanotherapy.

Keywords:
Exercise rehabilitationHamstringsInjury preventionMRIPhysiotherapy

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Area of Science:

  • Biomechanics and Exercise Physiology
  • Muscle Activation and Electromyography
  • Sports Injury Prevention

Background:

  • The hamstring muscles, comprising the biceps femoris (BF) and semitendinosus (ST), are crucial for lower limb function.
  • Understanding the selective activation of hamstring muscle components, particularly the BF long head (BFLongHead), is vital for optimizing training and rehabilitation.

Purpose of the Study:

  • To identify specific strength training exercises that selectively activate the biceps femoris long head (BFLongHead) muscle.
  • To compare hamstring muscle activation patterns during various common exercises.

Main Methods:

  • Recruited 24 recreationally active men for a two-part observational study.
  • Measured normalized electromyography (nEMG) ratios of lateral (BF) to medial hamstring (MH) during 10 exercises.
  • Utilized functional MRI (fMRI) to analyze spatial activation patterns during selected exercises.

Main Results:

  • Eccentrically, 45° hip extension showed the highest BF/MH nEMG ratio; Nordic hamstring and bent-knee bridge showed the lowest.
  • Concurrently, lunge and 45° hip extension yielded the highest BF/MH nEMG ratio; leg curl and bent-knee bridge yielded the lowest.
  • fMRI confirmed greater BFLongHead activation in 45° hip extension compared to Nordic exercises, which preferentially activated the semitendinosus.

Conclusions:

  • Significant heterogeneity exists in hamstring muscle activation across different exercises.
  • Hip extension exercises are effective for selectively targeting the long head of the biceps femoris.
  • Nordic hamstring exercises preferentially recruit the semitendinosus, with implications for injury prevention and targeted mechanotherapy.