In collaboration with the University of Iowa, the Palmer Center for Chiropractic Research will pursue the following specific aim: To determine the effects of 2 weeks (4 applications @ 2 per week) of HVLA-SM and LVVA-SM to the lumbo-pelvic region, compared to a control group receiving light effleurage and a sham mechanically assisted adjustment, on sensorimotor function as measured by: lumbo-pelvic repositioning ability, standing postural sway and response to sudden trunk loading;