Partial body weight support treadmill training speed influences paretic and non-paretic leg muscle activation, stride characteristics, and ratings of perceived exertion during acute stroke rehabilitation

Background: Intensive task-specific training is promoted as one approach for facilitating neural plastic brain changes and associated motor behavior gains following neurologic injury. Partial body weight support treadmill training (PBWSTT), is one task-specific approach frequently used to improve walking during the acute period of stroke recovery (<1 month post infarct). However, only limited data have been published regarding the relationship between training parameters and physiologic demands during this early recovery phase. Objective: To examine the impact of four walking speeds on stride characteristics, lower extremity muscle demands (both paretic and non-paretic), Borg ratings of perceived exertion (RPE), and blood pressure. Design: A prospective, repeated measures design was used. Methods: Ten inpatients post unilateral stroke participated. Following three familiarization sessions, participants engaged in PBWSTT at four predetermined speeds (0.5, 1.0, 1.5 and 2.0 mph) while bilateral electromyographic and stride characteristic data were recorded. RPE was evaluated immediately following each trial. Results: Stride length, cadence, and paretic single limb support increased with faster walking speeds (p ≤ 0.001), while non-paretic single limb support remained nearly constant. Faster walking resulted in greater peak and mean muscle activation in the paretic medial hamstrings, vastus lateralis and medial gastrocnemius, and non-paretic medial gastrocnemius (p ≤ 0.001). RPE also was greatest at the fastest compared to two slowest speeds (p < 0.05). Conclusions: During the acute phase of stroke recovery, PBWSTT at the fastest speed (2.0 mph) promoted practice of a more optimal gait pattern with greater intensity of effort as evidenced by the longer stride length, increased between-limb symmetry, greater muscle activation, and higher RPE compared to training at the slowest speeds.