Correlation between lower limb isometric strength and muscle structure with normal and challenged gait performance in older adults.

Background: Muscular parameters have been considered to influence gait of older adults, but it is still unclear which specific lower limb muscular parameters correlate with kinematics of overground and obstacle crossing in older adults.

Research Question: What lower limb muscular parameters correlate and explain kinematics of overground walking and obstacle crossing ability in the elderly?

Methods: Muscle structure was evaluated in 15 older individuals (75.4 ± 5 years) through measures of architecture (muscle thickness, fascicle length, and pennation angle) and muscle quality (echo intensity) from lower limb muscles (vastus lateralis, biceps femoris, rectus femoris, tibialis anterior, and gastrocnemius medialis). Muscle function was assessed through isometric strength of hip, knee and ankle joint muscles. Gait kinematics (toe and heel clearances, step length and gait speed) was evaluated during walking with and without obstacle crossing at preferred and maximal gait speeds. Correlation and regression analyses were performed considering a significance level of 0.05.

Results: Isometric strength did not correlate with gait kinematics and gait speed. Tibialis anterior thickness correlated with lead limb toe clearance, and vastus lateralis thickness with gait speed and step length. Vastus lateralis echo intensity correlated with step length and gait speed.

Significance: Tibialis anterior and vastus lateralis muscles deserve attention in physical training to improve gait of older adults. Specifically, tibialis anterior should receive more attention on exercise programs aiming at improvement of obstacle crossing, and knee extensors when aiming at improving gait speed and step length.