Infants' Age and Walking Experience Shapes Perception-Action Coupling When Crossing Obstacles.

This study examined the effects of age and walking experience on infants' ability to step over an obstacle. We videotaped 30 infants with one (mean [ M] age = 12.6 months), three ( M age = 14.7 months), and six months ( M age = 17.7 months) of walking experience walking on a pathway with and without an obstacle. We found a shorter stride and slower velocity for infants with one month of walking experience and for the walking condition with an obstacle than for other experience groups or for walking without an obstacle. Across all groups, the horizontal distance between an infant's foot and the obstacle was larger for the trailing leg than for the leading leg. The vertical distance for both legs was similar among 1-month walkers, increased for 3-month walkers, and was similar for the trailing leg of the 6-month walker group. The percentage of the interlimb coordination relative phase for the leading limb was smaller for 3- and 6-month walker groups. In conclusion, age and walking experience contribute to improving coupling between sensory information and motor action and to organization for stepping over an obstacle in infants.

Ideal treadmill speed to stimulate stepping in infants.

BACKGROUND: The motorized treadmill elicits stepping in infants, however the effects of belt speed on treadmill-elicited stepping patterns are still unknown. OBJECTIVE: To examine the effect of belt speed on treadmill-elicited infant stepping. METHODS: Six normally developing infants, aged between 11 and 13 months and acquiring independent walking, were videotaped while stepping on a treadmill at four belt speeds (0.1, 0.16, 0.22, and 0.28 m/s), with passive markers affixed to the major joints (shoulder, hip, knee, and ankle). The images were digitized and analyzed using the software programs Ariel Performance Analysis System, Matlab, and SPSS (Statistical Package for Social Sciences, v.10). The analyzed variables were the descriptive, temporal, coordinative, and angular characteristics of the treadmill-elicited steps at the four speeds. RESULTS: At 0.22 and 0.28 m/s, stride velocity and duration increased, and the duration of the stance phase decreased at 0.22 m/s. Moreover, at 0.22 and 0.28 m/s, the knee joint range of motion increased. CONCLUSIONS: The moderate and high speeds seem to be more appropriate to elicit stepping in infants who are acquiring independent walking, with 0.22 m/s being the speed that seemed the most appropriate. Article registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) under number ACTRN12609000517279.

Velocidade ideal da esteira para estimular passadas do andar em bebês / Ideal treadmill speed to stimulate stepping in infants

CONTEXTUALIZAÇÃO: A esteira motorizada desencadeia passadas em bebês similares ao andar. Entretanto, os efeitos da velocidade da esteira nas características das passadas desencadeadas por ela ainda são desconhecidos. OBJETIVO: Examinar o efeito da velocidade da esteira em passadas desencadeadas em bebês. MÉTODOS: Seis bebês com desenvolvimento típico, com idades entre 11 e 13 meses, iniciando o andar independente, foram filmados andando na esteira em quatro velocidades (0,10; 0,16; 0,22 e 0,28 m/s), com marcas passivas posicionadas em suas principais articulações (ombro, quadril, joelho e tornozelo). As imagens foram digitalizadas e analisadas com os softwares Ariel Performance Analysis System, Matlab e SPSS (Statistical Package for Social Sciences, v.10). As variáveis analisadas foram as características descritivas, temporais, coordenativas e angulares das passadas desencadeadas pela esteira nas quatro velocidades. RESULTADOS: Em 0,22 e 0,28 m/s, ocorre aumento da velocidade e duração da passada, além de uma menor duração da fase de apoio (FA) na velocidade de 0,22 m/s. Nas velocidades de 0,22 e 0,28 m/s,observa-se aumento da amplitude articular do joelho. CONCLUSÕES: As velocidades moderadas e rápidas parecem ser as mais indicadas para desencadear passadas em bebês que estão iniciando o andar independente, sendo ainda que a velocidade de 0,22 m/s parece ser a mais apropriada. Artigo registrado no Australian New Zealand Clinical Trials Registry (ANZCTR) sob o número ACTRN12609000517279.

BACKGROUND: The motorized treadmill elicits stepping in infants, however the effects of belt speed on treadmill-elicited stepping patterns are still unknown. OBJECTIVE: To examine the effect of belt speed on treadmill-elicited infant stepping. METHODS: Six normally developing infants, aged between 11 and 13 months and acquiring independent walking, were videotaped while stepping on a treadmill at four belt speeds (0.1, 0.16, 0.22, and 0.28 m/s), with passive markers affixed to the major joints (shoulder, hip, knee, and ankle). The images were digitized and analyzed using the software programs Ariel Performance Analysis System, Matlab, and SPSS (Statistical Package for Social Sciences, v.10). The analyzed variables were the descriptive, temporal, coordinative, and angular characteristics of the treadmill-elicited steps at the four speeds. RESULTS: At 0.22 and 0.28 m/s, stride velocity and duration increased, and the duration of the stance phase decreased at 0.22 m/s. Moreover, at 0.22 and 0.28 m/s, the knee joint range of motion increased. CONCLUSIONS: The moderate and high speeds seem to be more appropriate to elicit stepping in infants who are acquiring independent walking, with 0.22 m/s being the speed that seemed the most appropriate. Article registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) under number ACTRN12609000517279.