A randomized controlled trial of hamstring stretching: comparison of four techniques

Area of Science:

• Biomechanics
• Sports Medicine
• Physical Therapy

Background:

• Hamstring flexibility is crucial for athletic performance and injury prevention.
• Various stretching techniques exist, but their comparative efficacy remains under-researched.
• Understanding optimal methods can guide rehabilitation and training protocols.

Purpose of the Study:

• To compare the effectiveness of four different hamstring-stretching techniques.
• To identify the most efficacious method for increasing hamstring muscle length.
• To evaluate the impact of active versus passive stretching on flexibility.

Main Methods:

• A randomized controlled trial involving 100 participants (ages 21-57).
• Five groups tested different hamstring stretching techniques, including active and passive methods.
• Hamstring length and perceived tightness were measured at baseline, 4 weeks, and 8 weeks.

Main Results:

• Active stretching showed significant improvement compared to passive stretching after 4 weeks (p < 0.05).
• Improvements in active stretching groups declined between weeks 4 and 8.
• The straight leg raise (SLR) passive stretch group demonstrated the greatest improvement in hamstring length after 8 weeks.

Conclusions:

• Passive stretching, specifically the SLR technique, is superior for long-term hamstring flexibility gains.
• Proprioceptive neuromuscular facilitation (PNF) in active 90/90 stretches yielded better knee range of motion than passive methods.
• No correlation was found between hamstring flexibility improvements and age, initial tightness, or exercise frequency.