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Updated: May 6, 2026
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Muscle Imbalances: Testing and Training Functional Eccentric Hamstring Strength in Athletic Populations
Published on: May 1, 2018
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Geometric and architectural contributions to hamstring musculotendinous stiffness
J Troy Blackburn1, Derek N Pamukoff2
1Neuromuscular Research Laboratory, University of North Carolina, Chapel Hill, NC, USA; Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, NC, USA; Department of Orthopaedics, University of North Carolina, Chapel Hill, NC, USA; Program in Human Movement Science, University of North Carolina, Chapel Hill, NC, USA.
Clinical Biomechanics (Bristol, Avon)
|November 14, 2013
Summary
Hamstring stiffness, crucial for anterior cruciate ligament (ACL) protection, is influenced by strength and thigh fat. Increasing hamstring strength and reducing fat may help prevent ACL injuries.
Area of Science:
- Biomechanics
- Musculoskeletal health
- Sports injury prevention
Background:
- Hamstring musculotendinous stiffness is linked to reduced anterior cruciate ligament (ACL) loading.
- Females exhibit lower hamstring stiffness, potentially increasing ACL injury risk.
- Factors influencing hamstring stiffness, such as muscle geometry and architecture, remain unclear.
Purpose of the Study:
- To investigate the relationship between hamstring muscle geometry, architecture, and stiffness.
- To identify factors contributing to variations in hamstring stiffness.
Main Methods:
- Ultrasound imaging assessed biceps femoris long head cross-sectional area, pennation angle, fiber length, tendon stiffness, and posterior thigh fat thickness.
- Isometric strength testing and damped oscillatory technique measured hamstring strength and stiffness.
- Thirty healthy participants (15 males, 15 females) were included.
Main Results:
- Normalized hamstring strength and tendon stiffness were greater in males.
- Posterior thigh fat thickness was greater in females.
- Hamstring stiffness correlated positively with strength (r=0.535) and negatively with posterior thigh fat thickness (Spearman ρ=-0.305).
Conclusions:
- Greater posterior thigh fat may reduce hamstring stiffness by increasing intramuscular fat and shank mass.
- Training interventions aimed at enhancing hamstring strength and reducing fat mass could be beneficial for ACL injury prevention.
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