Differences in foot contact times between obese and non-obese postmenopausal women when crossing obstacles.

OBJECTIVE: This study aimed to investigate the foot contact time differences between obese and non-obese subjects during walking when crossing obstacles.

METHODS: Ninety-eight postmenopausal women were assigned to four groups, and their plantar pressure temporal data were collected using a two-step protocol during walking when crossing an obstacle set at 30% height of lower limb length of each subject. The initial, final, and duration of contact of 10 foot areas were measured.

RESULTS: Leading limb: (1) the heel groups initiated foot contact using the heel, and the non-heel groups initiated contact using the metatarsals; (2) heel obese subjects showed an earlier initial contact and a longer contact duration of metatarsals 2-3; (3) non-heel obese subjects showed an earlier midfoot initial contact. Regarding the trailing limb: (4) heel obese subjects showed an earlier midfoot initial contact and a longer contact duration of metatarsal 5; (5) non-heel obese subjects showed an earlier initial contact and a longer contact duration of metatarsals 4-5.

CONCLUSIONS: (1) The non-heel groups' foot rollover pattern may result from an attempt of rapidly restoring stability; (2) the heel obese subjects seem to regulate their plantar foot muscles to overcome their overweight; (3) the overweight of the non-heel obese subjects leads to a quicker backward foot roll-over from the metatarsals to the heel; (4) the overweight of the heel obese subjects can distort their footprints and/or their higher inertia may precipitate an anticipation of the midfoot contact, which can also explain the result observed for 5.