The purpose of this study was to examine the effects of increased SW on GRF and lower limb joint motion in healthy older adults during stair descent.Eight healthy older men (52.1 ± 7.4 years, 75.7 ± 10.0 kg, 1.75 ± 0.09 m) were recruited for the study. An instrumented 3-step staircase (FP-stairs, AMTI) mounted independently to two force platforms (1200 Hz, AMTI) with two additional customized wooden steps (4th and 5th steps) was used to collect GRF data during stair descent trials. Participants performed five stair descent trials at their pre-established self-selected speed at self-selected, wide, and wider SW. Loading rate of impact peak vertical GRF and peak medial GRF were greater with wider SW compared to normal and wide SW. Peak ankle eversion angle was reduced with increasing SW and peak ankle inversion moment was smaller in wider SW compared to normal and wide SW. Peak hip adduction angle was greater in wider SW while peak hip abduction moment was smaller in wider SW compared to normal and wide SW. More healthy participants will be tested to increase sample size. Older adults with medial compartment knee osteoarthritis (OA) are also currently being tested to compare the effects of increased SW on GRF, and lower extremity joint variables to healthy adults during stair descent.