Resultant center-of-pressure (CP) displacements result along mediolateral (ML) and anteroposterior (AP) axes from strategies mobilizing hips and ankles, respectively, and thus, should be largely influenced by the angles between the feet. To assess this relation and the effects of foot position on postural performance, 9 healthy young adults were tested. The main results, as the forefeet are spread farther apart (from 30° in endorotation to 120° in exorotation), indicate (1) a larger contribution of the estimated ankle mechanisms in the generation of the CP trajectories along the ML axis, (2) increased variances along the longitudinal axis of the feet, (3) a constant longitudinal pattern of the CP trajectories under each foot whose main axis displays a progressively increased angle with the inner borders of the feet, and (4) increased variances for CP displacements along both ML and AP axes. These data emphasize the importance of foot positioning in stance control, especially along the ML axis where spreading the forefeet apart progressively increases the contribution of the mechanisms mobilizing the ankles.
Patrice R. Rougier
Ross H. Sanders
A boost is a skill used in water polo to raise the body for the purpose of shooting for goal or passing, or defending against these. The purpose of this study was to investigate kinematic variables contributing to height achieved in a boost. The kinematics of the vertex, shoulders, and lower limbs of 16 players ranging in ability from novice to elite were quantified using three-dimensional videographic techniques. Maximum height of the vertex with respect to water level ranged from 0.50 m to 0.90 m. A multiple regression model comprising the squared maximum resultant foot speed, range of knee joint extension, and initial trunk angle with respect to the horizontal accounted for 74% of the variance in height achieved. Anteroposterior and medio-lateral motions assisted in maintaining foot speed throughout the period of knee extension. The foot orientations and direction of foot motion of the elite players suggested that effective technique involves the use of both drag and lift forces.
Jessa M. Buchman-Pearle, David C. Kingston, and Stacey M. Acker
plantarflexed kneel (PK). Participants first observed each movement performed by the researcher. Then, they practiced until they felt comfortable. No verbal instruction was provided to participants, beyond explaining what leg must step forward into the kneeling positions and the foot orientation when adopting
Adam M. Fullenkamp, Danilo V. Tolusso, C. Matthew Laurent, Brian M. Campbell, and Andrea E. Cripps
more flattened sagittal plane foot orientation at initial contact during MT running compared to OG running. Schache et al 15 observed differences in hip-flexion/extension (F/E) kinematics between MT and OG locomotion, along with significant differences across all temporal–spatial parameters