Alterations In Musculoskeletal Function And Body Composition In Children With Autism Spectrum Disorder

Abstract

Autism Spectrum Disorder (ASD) is a neurological disorder characterized by impaired social interaction and atypical behaviors. Children with ASD appear to have weaker muscular function and low bone mineral density. Recent studies have indicated that adolescents with ASD develop obesity and bone fracture incidence at a higher rate compared to typically developing peers (TDC). Limited information is available to identify levels of obesity and its relation to muscular function and body composition in children with ASD before they start puberty. PURPOSE: To determine whether differential body composition may affect muscular strength and function in children with ASD METHODS: Total of 40 adults, TDC and children with ASD participated in the study. Muscular strength (i.e., torque, work, and power) during knee extension and flexion was measured at 90, 150, and 210 °/sec in the lower extremity using Humac Norm Isokinetic Dynamometer. Maximal isometric forearm muscular strength was measured using a handgrip dynamometer. Body mass index (BMI), waist-to-hip ratio, and whole-body scan from Dual Energy X-Ray Absorptiometry were used to identify the body composition. RESULTS: Compared to control adults, TDC and ASD had lower BMI (20.1±0.7 TDC, 22.3±4.4 ASD vs. 27.2±2.3 Adults, kg/m2). All groups had similar percent body fat (26.4± 2.3 Adults, 29.8±1.83 TDC, 32.9±3.84 ASD, %) and percent lean body mass (69.5±2.2 Adults, 66.8±1.7 TDC, 64.4±3.6 ASD, %). However, compared to TDC, ASD children had significantly lower bone mass percentage (2.7±0.3 ASD vs. 3.2±0.2 TDC, %). Waist-to-hip ratio was significantly higher for ASD (0.91±0.04 ASD vs. 0.85±0.01 TDC). The maximal forearm and leg strength were significantly lower in ASD compared to TDC normalized for their body weight (30.2 ±5.2 ASD vs. 42.8 ± 2.5 TDC, kg). There is a significant inverse relationship with muscular strength and regional percent fat in the forearm. CONCLUSION: These findings suggest that body composition appeared to influence muscular strength in children with ASD. Less regional fat and higher bone mass rather than the total body fat may contribute for higher leg or forearm muscular strength in children with ASD. Supported by CASA RSCA Infusion, Central RSCA, and Undergraduate Research Grant, SJSU