The effect of scapular-retractor fatigue on external and internal rotation in patients with internal impingement.

Context: Scapular strengthening is thought to be an important component of the rehabilitation of patients with internal impingement.

Objective: To determine the effect of scapular-retractor-muscle fatigue on internal- and external-rotation-torque production in patients with internal impingement.

Design: Case control study.

Impact of muscle power and force on gait speed in disabled older men and women.

Background: The purpose of this study was to explore the relationship between muscle power output at different external resistances and performance of functional tasks. The authors hypothesized that power at 40% skeletal muscle 1 repetition maximum (1RM), in which contraction velocity is high, would explain more of the variability in tasks such as level walking than would peak power or 1RM strength, in which contraction velocity is lower.

Methods: Participants were men and women (n = 48; ages 65-91 years) with physical disability as evidenced by 2 or more deficits on the Medical Outcomes Study Short Form physical function subscale or a score of 9 or less on the Established Populations for the Epidemiologic Studies of the Elderly short physical performance battery.

Changes in function and disability after resistance training: does velocity matter?: a pilot study.

Objective: To compare the effects of high- and low-velocity resistance training on functional performance and disability outcomes in physically limited older women.

Design: A total of 16 wk of high-velocity resistance training or traditional low-velocity resistance training consisting of knee extension and leg press exercises was performed three times per week by 30 women with self-reported disability to compare their effect on functional performance and disability. Tests of dynamic balance, stair-climb time, chair-rise time, and gait velocity were used to assess changes in functional performance.

High-velocity resistance training increases skeletal muscle peak power in older women.

Objectives: Peak power declines more precipitously than strength with advancing age and is a reliable measure of impairment and a strong predictor of functional performance. We tested the hypothesis that a high-velocity resistance-training program (HI) would increase muscle power more than a traditional low-velocity resistance-training program (LO).

Design: Randomized controlled trial.