AIM Adolescents and young adults with cerebral palsy (CP) show reduced motor function and gait efficiency, and lower levels of habitual physical activity (HPA), than adolescents with typical development and children with CP. This study examined activity duration and patterns in this population in the Middle East through long-term monitoring of a large sample using accelerometers. METHOD Adolescents and young adults with bilateral CP at Gross Motor FunctionClassification System (GMFCS) levels II, III, and IV, were monitored in their habitual environment for four consecutive days with ActivPAL3 monitors. Time spent in sedentary, standing, and walking activities, and frequency of walking steps and transitions, were analysed for each GMFCS level.RESULTS Measurements were made on 222 participants (132 males, 90 females; mean age 16y 9mo SD 2y, range 13y 4mo-22y). The Mann-Whitney U test demonstrated significant differences (p<0.05) between GMFCS levels, showing reduced walking and standing activity and increased sedentary duration at higher GMFCS levels (p<0.001), except for increased standing time between GMFCS levels II and III (p=0.07). Participants in educational facilities exhibited less sedentary behaviour than those who were homebound (p<0.05).INTERPRETATION These descriptions of duration and frequency of active and sedentary behaviours may serve as a basis for recommendations to minimize inactivity in this population. Adolescents and young adults with CP in the Middle East demonstrate similar patterns of HPA to their peers in other regions.Habitual physical activity (HPA) may be defined as the magnitude and pattern of body movements during the usual activities of daily living, including sleep and rest, work, and leisure. Sedentary behaviour refers to activities that increase energy expenditure above the resting level by less than 50% and includes activities such as sleeping, sitting, lying down, and watching screen-based entertainment.1,2 Regular and intensive physical activity, even in individuals with disabilities, is directly associated with physical fitness, improved quality of life, and psychological functions; 3 low levels of activity contribute to the risk of chronic cardiovascular disease 4 and other health issues. 5Adolescents and young adults with cerebral palsy (CP) face many difficulties with functional mobility in their transitional growth stages because, during adolescence, gross motor function capacity and gait efficiency decline. 6 Additionally, adolescents with CP face a discontinuity of care; as paediatric rehabilitation ends and they do not qualify for paediatric services there are few adult rehabilitation services available to meet their health needs.7 Compared with younger children with CP, adolescents and young adults with CP exhibit lower levels of physical activity, less walking activity, and more sedentary behaviour, 8 and their activity decreases as gross motor function deteriorates. 8,9 Adolescents and young adults are less physically active than their peers with typical development...

Purpose: The comparison of habitual physical activity and sedentary time in teenagers and young adults with cerebral palsy (CP) with typically developed (TD) peers can serve to quantify activity shortcomings. Methods: Patterns of sedentary, upright, standing, and walking components of habitual physical activity were compared in age-matched (16.8 y) groups of 54 youths with bilateral spastic CP (38 who walk with limitations and 16 who require mobility devices) and 41 TD youths in the Middle East. Activity and sedentary behavior were measured over 96 hours by activPAL3 physical activity monitors. Results: Participants with CP spent more time sedentary (8%) and sitting (37%) and less time standing (20%) and walking (40%) than TD (all Ps < .01). These trends were enhanced in the participants with CP requiring mobility devices. Shorter sedentary events (those <60-min duration) were similar for TD and CP groups, but CP had significantly more long sedentary events (>2 h) and significantly fewer upright events (taking <30, 30–60, and >60 min) and less total upright time than TD. Conclusion: Ambulant participants with CP, as well as TD youth must be encouraged to take more breaks from being sedentary and include more frequent and longer upright events.

Purpose: Exercise interventions have been shown to increase motor capacities in adolescents with cerebral palsy; however, how they affect habitual physical activity (HPA) and sedentary behavior is unclear. The main objective was to correlate changes in HPA with changes in mobility capacity following exercise interventions. Methods: A total of 54 participants (aged 12–20 y) with bilateral spastic cerebral palsy at Gross Motor Function Classification System (GMFCS) levels II and III received 4 months of group progressive resistance training or treadmill training. Mobility measurements and HPA (averaged over 96 h) were made before and after interventions. Results: Averaged baseline mobility and HPA measures and improvements in each after both interventions were positively correlated in all participants. Percentage of sedentary/awake time decreased 2%, with significant increases in HPA measures of step count (16%), walk time (14%), and upright time (9%). Mobility measures and HPA changes were quite similar between Gross Motor Function Classification System levels, but improvement in HPA after group progressive resistance training was greater than after treadmill training (12% vs 4%) and correlated with mobility improvement. Conclusions: Mobility capacity improved after these interventions and was clearly associated with improved HPA. The group progressive resistance training intervention seems preferable to improve HPA, perhaps related to greater social interaction and motivation provided by group training.

Motor skill learning involves improvement in feedforward control, the ability to execute a motor plan more reliably, and feedback control, the ability to adjust the motor plan on the fly. The dependence between these control components and the association between training conditions and their improvement have not been directly examined. This study characterizes the contribution of feedforward and feedback control components to motor skill learning using the Arc Pointing Task (APT), a drawing task that requires high motor acuity. In experiment 1, 3 groups of subjects were tested with online visual feedback before and after training with online visual feedback (OF group), with knowledge of performance feedback that was presented after movement completion (KP group), and with both online and KP feedback (KP+OF group). While the improvement of OF group was not different from the improvement of KP+OF group, comparison of the KP and KP+OF groups revealed an advantage to the KP group in the fast test speed, suggesting that training without online feedback leads to a greater improvement in feedforward control. In experiment 2, subject's improvement was examined using test probes for estimating feedback and feedforward control. Both KP+OF and KP groups showed improvement in feedforward and feedback conditions with a trend toward a greater improvement of the KP group. Our results suggest that online visual feedback suppresses improvement in feedforward control during motor skill learning.

Comprehensive data sets for lower-limb kinematics and kinetics during slope walking and running are important for understanding human locomotion neuromechanics and energetics and may aid the design of wearable robots (e.g., exoskeletons and prostheses). Yet, this information is difficult to obtain and requires expensive experiments with human participants in a gait laboratory. This study thus presents an empirical mathematical model that predicts lower-limb joint kinematics and kinetics during human walking and running as a function of surface gradient and stride cycle percentage. In total, 9 males and 7 females (age: 24.56 ± 3.16 years) walked at a speed of 1.25 m/s at five surface gradients (-15%, -10%, 0%, +10%, +15%) and ran at a speed of 2.25 m/s at five different surface gradients (-10%, -5%, 0%, +5%, +10%). Joint kinematics and kinetics were calculated at each surface gradient. We then used a Fourier series to generate prediction equations for each speed’s slope (3 joints x 5 surface gradients x [angle, moment, mechanical power]), where the input was the percentage in the stride cycle. Next, we modeled the change in value of each Fourier series’ coefficients as a function of the surface gradient using polynomial regression. This enabled us to model lower-limb joint angle, moment, and power as functions of the slope and as stride cycle percentages. The average adjusted R2 for kinematic and kinetic equations was 0.92 ± 0.18. Lastly, we demonstrated how these equations could be used to generate secondary gait parameters (e.g., joint work) as a function of surface gradients. These equations could be used, for instance, in the design of exoskeletons for walking and running on slopes to produce trajectories for exoskeleton controllers or for educational purposes in gait studies.