Upper and lower extremity motor strength and performance tests were collected as previously described [57]. These include grip and pinch strength measured by hydraulic dynamometers, arm abduction, arm flexion, arm extension, hip flexion, knee extension, plantar flexion, and ankle dorsiflexion measured with handheld dynamometry; time and number of steps to walk 2.4 meters and to turn 360°; participants were asked to stand on each leg and then on their toes for 10 seconds. We record number of steps off the line when walking 8 feet (2.4 meters) heel-to-toe; and Purdue pegboard and finger tapping. A composite measure of global motor function was constructed by converting the raw score from each of the motor measures to z scores using the mean (SD) from all participants at baseline and averaging. Separate summary measures of strength and performance were also developed.
