The Relationship Between The Physical Strain Of Walking And Daily Activity Time In Individuals With Slowly Progressive Neuromuscular Diseases

Research Objectives To investigate the physical strain of walking and its relationship with daily activity time in individuals with neuromuscular diseases (NMD). Design Observational study. Setting Data were collected from multiple research projects at the Department of Rehabilitation Medicine at the Amsterdam UMC, location AMC. Participants Thirty-one adults with post-polio syndrome (N = 11), Charcot-Marie-Tooth disease (N = 12) and other slowly progressive NMD (N = 8) participated (age: 59.9 ± 14.3). Interventions Steady state oxygen consumption during comfortable 6-minute walking (VO2walk), peak oxygen uptake (VO2peak) during maximal cycle ergometry, and heart rate and step count during 7 consecutive days were assessed. Main Outcome Measures Physical strain was defined as the ratio of VO2walk and VO2peak (in %). Daily activity time was expressed as average daily step count and time spent in moderate (40-60% heart rate reserve) to vigorous (>60% heart rate reserve) physical activity (MVPA). Regression analyses assessed the relationships between physical strain, VO2walk, and VO2peak with daily activity time. Results Participants walked 8262 ± 3403 steps and physical strain during walking was 64% ± 15%. Physical strain was inversely related to step count (r2=.26, p=0.004), while VO2peak was positively related to step count (r2=.20, p=0.013) and inversely related to MVPA (r2=.14, p= 0.040). The other relations were not significantly correlated. Conclusions Physical strain of walking is high in patients with slowly progressive NMD compared to able-bodied individuals (27% ± 6%) [1], approximating vigorous exercise intensities. People with a higher physical strain take less steps daily. People with lower VO2peak take less steps daily, while spending more time in MVPA. The small proportions of explained variance indicate that more factors play a role in daily activity. Author(s) Disclosures None.