]. Postures, limb movements, and jumping were tested using a timed protocol of specific activities. Walking and running were tested using a 60-meter track, on which subjects walked and ran at 6 self-selected speeds. Stair climbing and descending were tested by timing subjects who climbed and descended a flight of stairs at two different speeds. Results: Correct identification rates averaged 98.9% for posture and limb movement type and 98.5% for gait type. Pooled correlation between predicted and actual speeds of walking and running was high (r ϭ 0.986, p Յ 0.0001). Discussion: IDEEA accurately measured duration, frequency, type, and intensity of a variety of daily PAs.

Higher 24-h EE in persons with early midstage HD is due to increased physical activity, both voluntary and involuntary. However, HD subjects are able to maintain positive energy balance when offered adequate amounts of food in a controlled setting.