Gait changes induced by a 6-min walking exercise in individuals with myotonic dystrophy type 1: relationship with muscle strength.

Abstract

Myotonic dystrophy type 1 is an inherited muscular dystrophy characterized by muscle weakness, myotonia, and balance deficits, contributing to early fatigue and increased risk of fall during walking. This study investigated gait changes due to continuous walking exercise. Fourteen individuals with myotonic dystrophy type 1 were included (age 42.0 ± 8.8 years, height 1.63 ± 0.10 m, mass 75.2 ± 22.2 kg). Maximal isometric hip and knee strength was measured using a handheld dynamometer. A 3D gait analysis, using a 12-camera optoelectronic system, was performed during a 6-min walking exercise on a quasi-oval track. A decrease in step length (-3.4 %, P = 0.002), walking speed (-7.1 %, P = 0.002) and cadence (-3.4 %, P = 0.013) was observed following the 6-min walking exercise. Double support time increased (10.0 %, P = 0.032) and maximum base of support width increased (5.7 %, P = 0.023), while center of mass amplitude decreased (-5.3 %, P = 0.048). Hip and knee extensor strength positively correlated with step length at the beginning of the 6-min walking exercise (P = 0.010 and P = 0.022 respectively). This study reveals key gait changes during a 6-min walking exercise in individuals with myotonic dystrophy type 1. Spatiotemporal changes highlight the importance of targeted interventions to manage muscle weakness and improve mobility in this population. Future studies should examine these changes over longer periods and in various conditions to better understand gait changes during typical daily activities in individuals with myotonic dystrophy type 1.