Ageing and isokinetic plantar flexion.

Area of Science:

• Biomechanics
• Exercise Physiology
• Gerontology

Background:

• Aging is associated with declines in muscle strength and performance.
• Understanding factors influencing plantar flexion torque is crucial for assessing mobility and function in different age groups.

Purpose of the Study:

• To compare isokinetic plantar flexion torques between young and older healthy men.
• To investigate the association of age, physical activity, and aerobic fitness (VO2max) with plantar flexion torque across various angular velocities.

Main Methods:

• Isokinetic plantar flexion torques were measured in 25 healthy men at five angular velocities (30-180°/s) using Cybex II.
• Subjects were categorized into young (approx. 22 years) and older (approx. 63 years), active and sedentary groups.
• Measurements included anthropometrics, body fat percentage, VO2max, and leisure energy expenditure; statistical analyses included ANOVA and regression.

Main Results:

• Plantar flexion torque declined significantly with increasing angular velocity across all subjects.
• Age was a significant determinant of torque, but VO2max explained a substantial portion of torque variance (47% at 30°/s).
• At the slowest velocity (30°/s), VO2max was a significant predictor, diminishing the independent effect of age.

Conclusions:

• Both increasing angular velocity and older age contribute to reduced plantar flexion torque.
• Aerobic fitness (VO2max) plays a critical role in maintaining plantar flexion torque, particularly at lower speeds, potentially mitigating age-related decline.
• These findings underscore the importance of aerobic conditioning for preserving muscle function throughout the lifespan.