The Stretch-shortening Cycle of Active Muscle and Muscle-tendon Complex: What, Why and How It Increases Muscle Performance?

The research topic of stretch-shortening cycles (SSCs) has been studied extensively, with findings suggesting that SSCs can increase muscle force, work, and power output during concentric contractions following an eccentric contraction. Research has found that the SSC-effect is present in the sarcomere itself and is velocity-dependent, with energy stored in titin during the eccentric phase contributing to the SSC-effect. Additionally, studies have found that SSCs can improve physical performance in young female handball players, increase muscle volume, fascicle length, pennation angle, torque and power, and enhance rowing performance.

Further research has shown that the energy cost per unit of muscle force is not reduced following a SSC compared to a pure shortening contraction, and that countermovement jump training is more effective than drop jump training for non-professional female volleyball players. Additionally, studies have suggested that the preload of the titin molecule, acting as a molecular spring, might be part of the mechanism that contributes to the SSC-effect, and that exhaustive stretch-shortening cycle exercise can lead to muscle damage, decreased active stiffness, and increased muscle-tendon unit length.

In summary, research has found that SSCs can increase muscle force, work, and power output, and improve physical performance in athletes. Additionally, studies have suggested that the preload of the titin molecule might be part of the mechanism that contributes to the SSC-effect, and that exhaustive stretch-shortening cycle exercise can lead to muscle damage and other changes.