Age-Related Differences in Muscle Shear Moduli in the Lower Extremity

Area of Science:

• Biomechanics
• Gerontology
• Musculoskeletal Health

Background:

• Muscle mechanical properties change with age, potentially affecting function and increasing fall risk in older adults.
• Understanding age-related muscle adaptations is crucial for developing targeted interventions.

Purpose of the Study:

• To investigate age-related differences in the shear moduli of the rectus femoris (RF), lateral gastrocnemius (LG), and soleus (SOL) muscles.
• To explore the relationship between muscle mechanical properties and functional outcomes in young versus elderly individuals.

Main Methods:

• Shear wave ultrasound elastography was employed to measure muscle shear moduli in 31 young and 49 elderly participants.
• Measurements were standardized to specific anatomical locations within the thigh and lower leg.

Main Results:

• Significantly lower shear moduli were observed in the RF and LG muscles of elderly individuals compared to young individuals.
• No significant age-related difference was found in the shear modulus of the SOL muscle.
• Reduced shear moduli in RF and LG suggest age-related declines in muscle stiffness.

Conclusions:

• Age-related decreases in RF and LG muscle shear moduli may contribute to reduced explosive muscle strength in the lower extremities of the elderly.
• These mechanical property changes could be a factor in the increased risk of falls among older adults.
• The soleus muscle appears to maintain its mechanical properties more effectively with age compared to RF and LG.