Electromyographic and cinematographic analysis of movement from a kneeling to a standing position in healthy 5- to 7-year-old children.
Physical therapists often use transitional postures such as half-kneeling to help children with movement dysfunction attain an upright posture. Little is known, however, about how healthy children activate lower extremity muscles to move the hip, knee, and ankle joints as they move from kneeling through half-kneeling to stand up against gravity. The purpose of this study was to describe movement from kneeling to standing in 10 healthy 5- to 7-year-old children. Electromyography was used to record the activity of four lower extremity muscles. Cinematography was used to record joint motion of the hip, knee, and ankle of the leg initiating movement, in addition to trajectories of specific anatomical landmarks as the children rose from a kneeling to a standing position. Greater active range of motion of the hip, knee, and ankle was necessary to move from a kneeling to a standing position using the half-kneel transitional posture than is required during normal gait. The activation patterns of the gastrocnemius, tibialis anterior, rectus femoris, and biceps femoris muscles of the leg initiating movement exhibited variability among subjects during the kneel-to-stand movement. Maximum joint range of motion and position of the hip, knee, and ankle joints at specific points in the movement exhibited less variability than patterns of muscle activation. The results showed that movement from a kneeling to a standing position in healthy children is quantifiable and can be used to help determine what normal components of movement are necessary to successfully master this movement against gravity that is antecedent to ambulation. Further studies are needed to investigate antigravity movement in younger children and in children with movement dysfunction to more fully understand normal and abnormal movement in children.