Free-living physical activity levels in children with cerebral palsy.

Abstract

Cerebral Palsy (CP) is a common motor disorder in children, leading to reduced physical activity (PA) and increased health risks. To complement traditional PA methods (e.g. accelerometers, self-reports), electromyography (EMG) provides physiologically relevant information on muscle activity during free-living. This study used EMG for assessing daily muscle activity in individuals with CP and their typically developing (TD) peers. Shorts with embedded EMG electrodes and hip-worn tri-axial accelerometer recorded daily PA in 8 children with spastic CP (mean age 14y 7mo, Gross Motor Function Classification System (GMFCS) I (n = 5), III (n = 3)) and 6 TD children (mean age 15y 4mo) during free-living. Daily EMG activity levels are reported as a percentage of mean EMG amplitude during the 6MWT. Inactivity time and light, moderate and vigorous PA are reported relative to recording time using established cut-off values for accelerometry, and EMG amplitude categorized based on a two-minute average from the middle of 6MWT. Free-living EMG inactivity (CP: 58.4 %, TD: 50.4 %) and activity levels did not differ statistically between CP and TD groups. Accelerometry showed a greater inactivity time than EMG in CP (p = 0.021) and TD (p = 0.010) groups. In CP, few statistically significant differences were observed between legs, muscles, and GMFCS levels. Free-living EMG monitoring did not reveal excessive muscle activity in individuals with CP during daily activities compared to TD peers. EMG detects light PA that accelerometry may underestimate, offering a more detailed view of daily muscle use.