How does wearing slippers affect the movement strategy while crossing over an obstacle?

Background: Wearing slippers may increase the risk of tripping while crossing obstacles, regardless of age. This is because slippers are more likely to leave the feet and come into contact with obstacles. However, how wearing slippers affects the movement strategy while crossing over an obstacle has not been clarified.

Research Question: How does wearing slippers affect the movement strategy while crossing over an obstacle?

Methods: Thirty healthy young adults crossed over an obstacle using a comfortable speed under two conditions: barefoot and wearing slippers. The moment when the leading or trailing limb was crossing the obstacle was defined as obstacle lead (OL) or obstacle trail (OT), respectively. The margin of stability (MoS) as a measure of stability was measured at OL and OT. Toe clearance and lower limb joint angles of the leading limb were measured at OL, and those of the trailing limb were measured at OT.

Results: Wearing slippers increased toe clearance and flexed the hip and knee joints, regardless of the crossing event (OL, OT). However, the ankle joint angle did not change between footwear conditions at OL and was significantly dorsiflexed in the slippered condition at OT. In addition, the MoS did not change between footwear conditions at OL and increased significantly in the slippered condition at OT.

Significance: The increase of the MoS at OT when wearing slippers is probably a conservative strategy to reduce the risk of falling forward when a trip occurs. More attention to avoiding tripping likely caused the ankle to dorsiflex and increased toe clearance. This conservative strategy and increased attention are most likely due to the slippers coming off easily. Since these strategies are probably safety measures to prevent tripping, slippers may not be appropriate footwear in terms of tripping risk.