The 130th Annual Meeting of APHA

Abstract #51224

Ian R. Lanza, University of Massachusetts, 30 Eastman Lane, 110 Totman, Amherst, MA 01003, 413-545-5305, irl@excsci.umass.edu

Human skeletal muscle contraction speed slows with age. The impact of this slowing on the torque-velocity and power-velocity relationships is not fully understood. To compare these relationships in functionally distinct muscle groups, the ankle dorsiflexors and knee extensors were studied. Subjects performed maximal voluntary concentric contractions (MVCs) at pre-set target velocities using an isokinetic They also performed isometric MVCs at regular increments throughout the same range of motion used for isovelocity trials. To account for differences in strength across subjects, the torque-velocity relationship was expressed relative to maximal isometric torque. Time to target velocity was longer in older subjects in the dorsiflexors (p=0.01), but not in the knee extensors (p=0.12). Older subjects produced less torque at all velocities for both dorsiflexors (p=0.05) and knee extensors (p<0.001). Peak power was lower in older subjects for both dorsiflexors (p=0.01) and knee extensors (p=0.005), particularly at higher velocities, demonstrating a progressive impairment in muscle function as contraction velocity increases. These results are functionally important as activities of daily living rely heavily on dynamic contractions of varying velocities.

Learning Objectives:

• At the conclusion of the presentation, the participant should be able to identify how the torque and power relationships change in older skeletal muscle.

Keywords: Aging,

Presenting author's disclosure statement:
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.