The Stretch Shortening Cycle

The Stretch Shortening Cycle (SSC), also known as the myotatic reflex, is the process of muscle stretching directly followed by shortening of the muscle. These rapidly occurring contractions create an enhancement of the elastic characteristics of the muscles equating to a more forceful concentric contraction. The elastic characteristics of muscles are similar to that of a rubber band, what happens when you stretch a rubber band and let it go? The band rapidly snaps back, returning to its original shape. This process potentially improves power production, enhances momentum and minimises workloads during performance.

When a rubber band is held stretched, it loosens, losing shape and the reflex characteristics are minimised. This is similar to slow contractions of muscle, held stretched; they lose their stored energy, therefore diminishing power production. As a result an emphasis is placed upon speed of movement within power based movements.

An example of the stretch shortening cycle can be seen within the examples below, note the rapid activation of the muscles creating momentum:

Power clean

http://www.youtube.com/watch?v=fGESkE-GzUE

References

• Hume, Keogh and Reid. The Role of Biomechanics in Maximising Distance and Accuracy of Golf Shot. Sports Medicine, 2005, Volume 35, Issue 5, Pages 429-449.

• Laaksonen M.S, Kivela R, Kyrolainen H, Sipila S, Selanne H, Lautamaki R, Nuutila P, Knuuti J, Kalliokoski K.K and Kom P.V. Effects of Exhaustive Stretch-Shortening Cycle Exercise on Muscle Blood Flow During Exercise. Acta Physiologica, April 2006, Volume 186, Issue 4, Pages 261-271.

Thanks,
Mitch