Effects of water immersion on gait initiation: part II of a case series after incomplete spinal cord injury.

Study design: Case series. Objectives: This case series describes how the aquatic environment influences gait initiation in terms of the center of pressure (COP) excursion, impulses, trunk acceleration, and perceptions of participants with incomplete spinal cord injury (iSCI). Setting: Tertiary Rehabilitation Hospital, Ontario, Canada. Methods: Five individuals with iSCI (four cervical injuries/one thoracic injury, AIS D) participated in the study. Baseline clinical balance was evaluated by Berg Balance Scale and Mini-Balance Evaluation System Test. Participants initiated gait on a waterproof force plate and walked ~4 steps, in water and on land. COP trajectories during anticipatory and execution phases, impulses, and trunk acceleration parameters were investigated. Perceptions of walking in both environments were obtained using an interview. Results: COP trajectory was prominently longer when individuals stepped forward. A decrease in velocity of COP was observed predominantly in the AP direction during stepping. Non-normalized vertical impulses decreased as the AP impulses increased, in water compared to land. Upper to lower trunk acceleration ratios showed how water resistance influenced the lower trunk acceleration. Most of participants reported that walking in water was challenging, but safer than on land. Conclusions: Participants with higher balance function seemed to have more pronounced changes in anticipatory and execution phases' duration, length and velocity of COP. A faster anticipatory phase and a slower execution phase were observed in water than on land. Participants walked in water using a different trunk control strategy than on land and reported no fear of falling when walking in water versus land.