Recreational older ballet dancers fall less with more effective reactive balance control than non-dancers after a slip during gait.

Abstract

Recent work revealed that recreational ballet practice reduces older adults' fall risk after a standing-slip perturbation. However, whether such ballet practice can lead to decreased falls and better reactive motor control after a gait-slip among older adults remains unclear. This study investigated whether ballet reduces older adults' gait-slip falls and the possible neuromuscular and biomechanical mechanisms responsible for fall risk reduction. Protected by a safety harness, 15 older recreational ballet dancers and 21 age- and sex-matched non-dancers experienced a single unexpected slip while walking on a treadmill. The slip acceleration, duration, and displacement were standardized at 8 m/s², 0.2 s, and 16 cm, respectively. Motion and electromyography data were collected during the gait-slip trial. The outcomes included slip-faller rate as the primary outcome and the following secondary ones: dynamic gait stability, slipping foot displacement, recovery stepping performance, trunk movement, and recovery leg muscle electromyography latency (rectus femoris, biceps femoris, medial gastrocnemius, and tibialis anterior). The results revealed that fewer dancers fell after the gait-slip (p = 0.029). Dancers displayed better stability at recovery foot touchdown (p = 0.012), a longer (p = 0.002) and faster (p = 0.009) step, shorter slipping foot displacement (p = 0.031), less backward trunk velocity at touchdown (p = 0.011), and shorter latencies for all four muscles (p≤0.038). The results suggest that older dancers are more resilient to an unexpected gait-slip and display better reactive balance control responding to the slip perturbation, which could be related to their more effective recovery stepping, better trunk movement control, and faster leg muscle activations.