Effects of a 4-week static stretch training program on passive stiffness of human gastrocnemius muscle-tendon unit in vivo

Eur J Appl Physiol. 2012 Jul;112(7):2749-55. doi: 10.1007/s00421-011-2250-3. Epub 2011 Nov 29.


Static stretch is commonly used to prevent contracture and to improve joint mobility. However, it is unclear whether the components of the muscle-tendon unit are affected by a static stretch training program. This study investigated the effect of a four-week static stretch training program on the viscoelastic properties of the muscle-tendon unit and muscle. The subjects comprised 18 male participants (mean age 21.4 ± 1.7 years). The range of motion (ROM), passive torque, myotendinous junction (MTJ) displacement and, muscle fascicle length of the gastrocnemius muscle were assessed using both ultrasonography and a dynamometer while the ankle was passively dorsiflexed. After the initial test, the participants were assigned either to a group that stretched for 4 weeks (N = 9) or to a control group (N = 9). The tests were repeated after the static stretch training program. The ROM and MTJ displacement significantly increased, and the passive torque at 30° significantly decreased, in the stretching group after the study period. However, there was no significant increase in muscle fascicle length. These results suggest that a 4-week static stretch training program changes the flexibility of the overall MTU without causing concomitant changes in muscle fascicle length.

MeSH terms

  • Adult
  • Ankle Joint / physiology*
  • Elastic Modulus / physiology
  • Humans
  • Male
  • Muscle Stretching Exercises / methods*
  • Muscle, Skeletal / anatomy & histology
  • Muscle, Skeletal / physiology*
  • Physical Fitness / physiology*
  • Range of Motion, Articular / physiology*
  • Tendons / anatomy & histology
  • Tendons / physiology*
  • Viscosity