Effect of various treadmill interventions on the development of joint kinematics in infants with Down syndrome

Background Infants with Down syndrome (DS) have delayed walking and produce less-coordinated walking patterns. Objective The aim of this study was to investigate whether 2 treadmill interventions would have different influences on the development of joint kinematic patterns in infants with DS. Design Thirty infants with DS were randomly assigned to a lower-intensity, generalized (LG) treadmill training group (LG group) or a higher-intensity, individualized (HI) treadmill training group (HI group) and trained until walking onset. Twenty-six participants (13 in each group) completed a 1-year gait follow-up assessment. Methods During the gait follow-up assessment, reflective markers were placed bilaterally on the participants to measure the kinematic patterns of the hip, knee, and ankle joints. Both the timing and the magnitude of peak extension and flexion at the hip, knee, and ankle joints, as well as peak adduction and abduction at the hip joint, in the 2 groups were compared. Results Both the LG group and the HI group showed significantly advanced development of joint kinematics at the gait follow-up. In the HI group, peak ankle plantar flexion occurred at or before toe-off, and the duration of the forward thigh swing after toe-off increased. Limitations Joint kinematics in the lower extremities were evaluated in this study. It would be interesting to investigate the effect of treadmill interventions on kinematic patterns in the trunk and arm movement. Conclusions The timing of peak ankle plantar flexion (before toe-off) in the HI group implies further benefits from the HI intervention; that is, the HI group may use mechanical energy transfer better at the end of stance and may show decreased hip muscle forces and moments during walking. It was concluded that the HI intervention can accelerate the development of joint kinematic patterns in infants with DS within 1 year after walking onset