Associations of Lower Limb Muscle-Tendon Properties with Dual-Task Gait Variability: A Cross-Age Study

This study is the first to investigate the association between lower limb muscle-tendon mechanical properties and dual-task gait variability using a handheld, non-invasive myotonometer (MyotonPRO).

A cross-sectional design was employed, involving 48 participants (older adults: 72.05 ± 3.52 years; younger adults: 24.8 ± 2.36 years). The stiffness and elasticity of dominant lower limb muscles and tendons were assessed using the MyotonPRO. Gait variability-including step length, stride length, and gait cycle time-was measured using the OptoGait system.

Compared to the younger group, older adults showed increased stiffness of the patellar tendon (p < 0.001) and decreased stiffness of the Achilles tendon (p < 0.047). Additionally, both the rectus femoris and biceps femoris exhibited significantly higher stiffness (p < 0.05) and reduced elasticity (p < 0.001). Patellar tendon stiffness was positively correlated with gait variability (r = 0.55 to 0.68, p < 0.01), whereas Achilles tendon stiffness showed a negative correlation (r = -0.32 to -0.40, p < 0.05).

This study provides preliminary evidence linking muscle-tendon mechanical properties with dual-task gait stability in older adults. Increased stiffness in the patellar tendon and decreased stiffness in the Achilles tendon suggest these structural characteristics may play a crucial role in gait control and hold potential as predictive markers of fall risk. Linking non-invasive MyotonPRO-derived mechanical properties with key spatiotemporal gait parameters may support its potential use in the early detection of gait instability in older adults.