WEDNESDAY, July 21 (HealthDay News) -- Wearing high-heeled shoes over the long term leads to shortening of muscle fascicles in the calf as well as increased stiffness of Achilles' tendons, according to research published online July 16 in the Journal of Experimental Biology.

Robert Csapo, of the Manchester Metropolitan University in the United Kingdom, and colleagues analyzed data from 11 women who wore high heels for an average of 60.7 hours a week, and a control group of nine women who usually wore flat shoes. Women underwent assessments including magnetic resonance imaging and ultrasound.

The researchers found that the high-heel group had shorter gastrocnemius medialis fascicle length (49.6 versus 56 mm), which resulted in greater tendon-to-fascicle length ratios. They also had greater Achilles' tendon cross-sectional area and Achilles' tendon stiffness.

"In conclusion, we observed shortened gastrocnemius fascicle length and increased Achilles' tendon stiffness in habitual high-heel wearers, which might reduce the ankle active range of motion and thus explain the discomfort these women experience when walking in flat shoes. These results strongly support the hypothesis that muscle structure may adapt to a chronic change in functional demand. Functionally, the observed muscle-tendon unit adaptations seem to compensate for each other since no significant differences in torque-angle and torque-velocity relationships were observed between the high-heel and control group women," the authors conclude.

Abstract
Full Text (subscription or payment may be required)