Article

The purpose of this study was to compare the two-dimensional kinematic and
electromyographic (EMG) changes during the squat-to-reach task in older and young
adults. Twenty-six older adults and thirty-three young adults were studied. A
16-channel telemetry system was used for recording muscular activity and
kinematic data during two trials of a squat-to-reach task. Surface EMG data were
recorded on select muscles of the trunk and the lower extremity on the dominant
side. An electrogoniometer was fixed over the knee joint, and an inclinometer was
fastened on the head and thigh to record kinematic data. The task was split into
six movement phases based on the angular displacement and velocities of the knee
joint. The mean values of the maximal displacements in the sagittal plane of the
head, knee, and thigh were significantly (p<0.05) lower, but those in the frontal
plane of the head and thigh were significantly (p<0.05) higher in older adults
than in young adults. Thigh muscle activities were significantly (p<0.05) higher
in older adults than in young adults throughout the movements. The trunk and leg
muscles contracted earlier, but the hip adductors contracted later in older
adults compared to young adults (p<0.05). The older adults squatted in a shallow
and heel-off posture during forward reaching tasks. Therefore, older adults had
increased lateral flexion of the head to compensate for insufficient knee flexion
during the squat-to-reach movement and required increased activity of the posture
muscles to maintain lateral stability.
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Langue : ANGLAIS