Contractile properties of elderly human triceps surae

Area of Science:

• Gerontology
• Human Physiology
• Muscle Physiology

Background:

• Aging is associated with declines in muscle mass and strength.
• Understanding age-related changes in specific muscle groups like the triceps surae is crucial for maintaining mobility and function in the elderly.

Purpose of the Study:

• To assess the reliability of measuring maximal electrically evoked and voluntary contractions of the triceps surae in elderly men.
• To compare the contractile properties and fatigue resistance of triceps surae muscle in elderly men versus young adults.

Main Methods:

• Repeated measurements of maximal voluntary contraction (MVC) and electrically evoked contractions (twitch and tetanic) over several weeks in 13 elderly men (mean age 69.6 years).
• Subjects were habituated to stimulation protocols.
• Comparison of elderly muscle properties (time-to-peak tension, half relaxation time, maximal tetanic tension, relative force loss during fatigue test) with previously reported data from young subjects.

Main Results:

• Maximal voluntary contraction (MVC) increased significantly between the first and second measurements, then remained stable.
• Elderly muscle demonstrated slower contraction (increased time-to-peak twitch tension) and relaxation (increased half relaxation time) compared to young muscle.
• Maximal tetanic tensions at 10 and 20 Hz were significantly lower in elderly men.
• Elderly men showed a greater relative loss of tension during a 2-minute fatigue test.

Conclusions:

• Muscle function in the elderly can be reliably assessed using electrophysiological methods.
• The triceps surae muscle in elderly individuals is weaker, contracts more slowly, and exhibits greater relative fatigue than in younger individuals.