Effect of added mass on human unipedal hopping at three frequencies.

Although more commonly done by children, hopping appears to be a rich source of neuromuscular and biomechanical information on adults. Given prior research on the independent effects of hopping frequency and added mass, this study assessed whether these would interact to affect vertical stiffness, contact duration, and lower extremity kinematics during unipedal hopping. Vertical force and two-dimensional kinematics were measured in 10 healthy males hopping at three frequencies: their preferred hopping frequency and frequencies 20% higher and 20% lower, in two conditions with added mass (body mass+10% and body mass+20%).

Effect of frequency on human unipedal hopping.

All mature forms of locomotion involve periods of unilateral stance. Unipedal hopping may provide useful information about the neuromuscular and biomechanical capabilities of a single lower extremity in adults. This study investigated whether hopping influenced vertical stiffness and lower extremity angular kinematics during human unipedal hopping.

Qualitative analysis of lumbar stabilization using point light and normal video displays.

Professionals in many fields use qualitative analysis to improve human movement. In previous research examining the reliability of physical therapists' qualitative assessments of lumbar stabilization, three experienced observers showed substantial agreement when viewing point light displays, but only moderate agreement when observing normal video displays. Replication of these findings in a larger group of less experienced observers would strengthen the notion that point light displays enhance qualitative analysis.

Effect of added mass on human unipedal hopping.

Although hopping is considered a children's activity, it can be used to provide insight into the neuromuscular and biomechanical performance of adults. This study investigated whether mass added during unipedal hopping altered the vertical stiffness, hopping period, and angular kinematics of the lower extremity of adults. Measures of two-dimensional kinematics and vertical force were made from 10 healthy men during hopping at a preferred period under three conditions: Body Mass, Body Mass+10%, and Body Mass+20%.