Affiliations: [a] The Clinical Kinesiology Research Laboratory, School
of Physical Therapy and Rehabilitation Science, The University of Montana,
Missoula, MT 59812-4680, USA
Note: [] Address for correspondence: Richard L. Gajdosik, Professor and
Director, Clinical Kinesiology Research Laboratory, School of Physical Therapy
and Rehabilitation Science, The University of Montana, Missoula, MT 59812-4680,
USA. Tel.: +1 406 2434753; Fax: +1 406 2432795; E-mail:
[email protected]
Abstract: The purpose of this study was to compare the dynamic elastic and
static viscoelastic stress-relaxation (VSR) properties of the calf
muscle-tendon unit (MTU) between men and women. A Kin-Com® dynamometer
moved the ankle of 15 men and 14 women (age range 23–35 years) from
plantarflexion to maximal dorsiflexion (DF) at 5°/s with negligible surface
electromyogram activity to measure the dynamic passive elastic properties. The
ankle was then moved to three DF angles defined at 100%, 90% and 80% of the
maximal DF force and held for 60 s each to measure the static VSR as the torque
decline. ANOVA procedures indicated that the men had greater absolute dynamic
maximal passive DF torque, full stretch mean torque, absorbed passive elastic
energy (area under the curve) and passive elastic stiffness through the full
stretch and through the last 10° of the stretch (P⩽0.014). All but the
full stretch stiffness remained significantly greater when controlled for body
mass (P⩽0.042). The absolute torque decline for the three static stretches
showed significant group, time and interaction effects (P<0.001). The
percent torque decline during the first 15 s of static stretch, normalized to
the total percent decline (100%) was greater for men at the 90% (P=0.049) and
80% (P=0.036) stretch angles. The results indicated that the calf MTU of men
has greater dynamic elastic and static VSR properties than women, which may
influence ambulatory functional activities and adaptations to therapeutic
stretching.
Keywords: Calf muscle-tendon unit, dynamic elastic properties, static viscoelastic properties, men, women
