Discrete bandwidth visual feedback increases structure of output as compared to continuous visual feedback in isometric force control tasks.

Background: Performance variability measures provide a partial picture of force control ability. Nonlinear analyses can reveal important information related to the randomness and complexity of the data, providing a more complete picture of the physiological process.

Methods: We investigated the effects of visual feedback on the structure and performance of the force output from isometric force control tasks.

Effects of carried weight on random motion and traditional measures of postural sway.

The purpose of the study was to investigate the effects of load weight carried by soldiers upon postural sway. Fourteen US Army enlisted men participated. Postural sway and muscle activity were measured while participants stood on a force plate.