DYNAMIC STRETCHING IN A WARM-UP PREVENTS STATIC STRETCHING NEGATIVE EFFECTS ON THE KNEE
Cottrell, T. (2009). The effects of static and dynamic stretching protocols on knee torque at varying angular velocities. ACSM 56th Annual Meeting, Seattle, Washington. Presentation Number 803.
"Evidence suggests that static stretching protocols diminish skeletal muscle force and power output capabilities when compared to dynamic stretching. Athletes will frequently apply both dynamic and static range of motion exercises as part of a warm-up protocol; therefore it is necessary to determine whether static stretching will limit force output capabilities when combined with dynamic stretching."
This study compared maximal knee torque at varying speeds following static stretching, dynamic stretching, and combined static-dynamic stretching protocols. Ss (M= 7; F = 6) with no existing knee pathologies reported for testing on five separate days. Day one was for test familiarization, day two was for baseline testing, and days three to five were randomized for one of three warm-up protocols. Protocol one involved static stretching of upper leg musculature; protocol two involved dynamic stretching of upper leg musculature; and protocol three combined both dynamic and static stretching protocols. All testing was performed unilaterally on a Biodex isokinetic dynamometer using a concentric-concentric knee flexion-extension protocol. Total work and peak torque of the hamstrings and quadriceps musculature were recorded at angular velocities of 60 and 300 degrees per second.
Knee flexor total work at 60 degrees per second was significantly greater in the combined stretching trial than in the static stretching trial. Similarly, knee extensor peak torque at 300 degrees per second was significantly greater in the combined stretching trial when compared to the static stretching trial.
Implication. Combining static stretching with a dynamic stretching in a warm-up protocol does not diminish the ability of a muscle to maintain force output. The combination is more effective than either form of stretching alone because dynamic stretching is not shown to be significantly more effective than static stretching. [Whether this study's effect would be replicated on other joints remains to be researched.]
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