Gender comparisons of dynamic restraint and motor skill in children.

OBJECTIVES: To assess differences in neuromuscular dynamic restraint between high-skilled and low-skilled prepubescent girls and boys. To determine the contribution of sport experience and physical characteristics to motor skill. SUBJECTS: Nineteen girls and 17 boys (8.89-9.40 y) participated. INTERVENTION: Isometric hamstring and quadriceps muscle strength was assessed. Subjects performed 3 landing trials for measurement of preparatory EMG and vertical leg stiffness. Motor skill was assessed through analysis of 12 fundamental tasks. Sport experience was reported as hours per week and total years in organized and nonorganized activity. OUTCOME MEASURES: Dynamic restraint variables of isometric strength, preparatory EMG activity, and vertical leg stiffness were measured between groups. The contributions of time in sport, type of sport, and physical characteristics on skill were analyzed. RESULTS: No significant gender or skill differences were found in quadriceps strength (P = 0.73), hamstring strength (P = 0.96), hamstring-to-quadriceps ratio (P = 0.71), or vertical leg stiffness (P = 0.38). Low-skilled children exhibited significantly greater (47.8%) preparatory hamstring-quadriceps coactivation than high-skilled subjects (P = 0.03). Participation in organized and nonorganized sport accounted for 29% of the variance in motor skill. CONCLUSIONS: Neuromuscular differences between genders were not observed, but dynamic restraint EMG measures differed between skill levels. The factors predisposing females to noncontact injuries may develop prepuberty to postpuberty from a combination of variables. Greater coactivation in the low-skilled group appears consistent with immature feedforward neuromuscular control strategies. These unrefined motor skills are less economical, may compromise dynamic restraint, and appear partially determined by sport experience.

Will safety release cords on children's cameras prevent strangulation?

This study investigated the automatic safety release mechanisms on neck cords for children's cameras. The purpose of the safety release mechanism is to reduce accidental strangulation associated with children's toys that have neck cords. The horizontal pull forces that activate the automatic safety release mechanism were measured for two different styles of release mechanisms for neck cords. When these forces were compared to forces associated with child strangulation, the automatic safety mechanisms released at higher forces than the forces associated with accidental strangulation or death, which is contrary to what was intended and creates a false sense of security for parents who select a toy camera with such a device.

How do children climb out of cribs?

48 children between the ages of 16 and 32 mo. were observed climbing out of a crib. Each child was observed four times climbing out of the crib. All the children were able to walk independently and were less than 35 in. tall. Two different climbing patterns were identified and associated with a location of the climbing event within the crib environment. Most children (90%) climb from a crib by first moving to a corner of the crib and then start climbing from the crib. The remaining 10% of the children used a side-climbing pattern in at least one of the four observations. Crib safety standards have eliminated the most common catch-point, the cornerpost extension from cribs. Since at least 10% of the children climbed over the side of the crib rather than at the corner, any potential catch-points should be eliminated from the complete perimeter of the crib.