Stretching exercise can help increase flexibility, but sometimes it comes with a cost of decreased muscle performance immediately afterward. Two common types of stretching are static and contract-relax, or “PNF” stretching (proprioceptive neuromuscular facilitation). In a recent review paper, I discussed the advantages and disadvantages of different stretching techniques: static stretching may decrease immediate muscle performance, while contract-relax stretching may be more beneficial for immediate gains in range of motion with less detriment to muscle performance.
PNF stretching involves a muscle contraction prior to initiation of the stretch. It’s thought that contracting the target muscle or its antagonist prior to stretching may increase muscle length through neurologic-mediated mechanisms. While effective, PNF techniques often require a partner to provide resistance to the muscle contraction prior to the stretch.
The Thera-Band® Stretch Strap was designed to support both static and contract-relax stretching without the need for a partner. Professor David Behm and his colleagues at Memorial University of Newfoundland in St. John’s, Canada, recently published a study in the Journal of Strength and Conditioning Research that compared the Thera-Band Stretch Strap to partner-assisted stretching for hamstring flexibility.
13 healthy adults participated in the study. Each performed 5 different hamstring stretching techniques on separate days in random order: Stretch Strap with isometric, concentric and eccentric contraction, and partner-assisted static and isometric contraction stretching. Contractions were held for 5 seconds and stretches were held for 6 seconds at a ‘position of discomfort’ at the end of the range of motion. Hip range of motion (ROM), muscle reaction time, and movement velocity were measured before and immediately after each stretching condition.
The researchers found that all stretching techniques significantly increased hip ROM, but there was no significant difference between the techniques. Interestingly, both the Stretch Strap and partner-assisted techniques reduced movement velocity, while maintaining the same reaction times regardless of the type of stretch. They concluded that the Stretch Strap is as effective as partner-assisted stretching at increasing ROM, but stated that “competitive athletes should use these techniques to improve flexibility in a separate stretching routine, and not immediately before training and competition.”
Based on these results, the Stretch Strap fulfilled its intent stated by the authors “to make PNF stretching techniques a more viable option to improve range of motion and overall flexibility for a single individual. The elasticity of the Stretch Strap provides resistance for muscle contractions potentially replacing the need for a partner.”
Learn more about Dr. Behm’s study by listening to his podcast interview following presentation of his research at the TRAC 2011 meeting.
REFERENCE: Maddigan ME, Peach AA, Behm DG. A comparison of assisted and unassisted proprioceptive neuromuscular facilitation techniques and static stretching. J Strength Cond Res. 2012 May;26(5):1238-44.