Gajdosik RL, Vander Linden DW, McNair PJ, Riggin TJ; The University of Montana, Missoula, MT. rgajdos@selway.umt.edu.

PURPOSE: The purpose of this pilot study was to explore the effects of separate 8-week stretching and strengthening exercise programs on the length and passive resistive force properties of the calf muscles of older women. SUBJECTS: Fifteen older women aged 77 ± 6 years (68-87 years) with active dorsiflexion (DF) ROM £ 10° participated. METHODS AND MATERIALS: The maximal passive DF angle of the right ankle was measured blindly using a Kin-Comâ force dynamometer. The ankle was then stretched from plantarflexion to the maximal DF angle at 5° /s with minimal surface EMG activity recorded from the soleus, gastrocnemius, and tibialis anterior muscles. The angles and passive resistive force recordings were interfaced with the EMG recordings. The subjects were then randomly assigned to one of three groups: 1) Stretching Group (n = 5), 2) Strengthening Group (n = 5), and 3) Control Group (n = 5). The Stretching Group completed unilateral wall stretches for 10 repetitions a session, holding each stretch 15 seconds. Both legs were stretched three days each week. The Strengthening Group completed a progressive resistive exercise program of unilateral heel-raises for both legs three days each week. The Control Group did not exercise. After 8-weeks all subjects were retested. ANALYSES: Descriptive statistics were tabulated for the following variables: 1) maximal DF angle (maximal length), 2) full stretch ROM (extensibility), 3) maximal DF force (Newtons [N]), 4) full stretch mean force (N), and 5) total absorbed elastic energy (area under the curve [° × N]). The variables were examined using ANOVA procedures for repeated measures. RESULTS: For the Stretching Group the maximal DF angle increased from 12 ± 3° to 19 ± 3° and the full stretch ROM increased from 37 ± 11° to 51 ± 8° (P < 0.05). Their maximal DF force increased from 69 ± 13 N to 115 ± 37 N, the full stretch mean force increased from 22 ± 3 N to 32 ± 10 N, and the total absorbed elastic energy increased from 802 ± 278 ° × N to 1762 ± 659 ° × N (P < 0.05). Neither the Strengthening Group nor the Control Group showed significant changes. CONCLUSIONS: The initial results indicated that the length and passive resistive force properties of the calf muscles of older women with limited DF ROM may show stretch-specific mechanical adaptations to a stretching program. The strengthening program had a negligible influence on the passive properties measured. Increases in the length and extensibility of the calf muscles, coupled with increases in their passive resistive forces, may help to improve performances in ambulation and other functional activities. Studies are being conducted to explore these possibilities. FUNDING SOURCE: RehabNet~West NIH Grant No. R24 HD39629-04 and The Murdock Charitable Trust Foundation.

Copyright 2004 by the American Physical Therapy Association

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