Effect of Blood Flow-restricted Exercise Frequency on Strength Recovery Following Incomplete SCI

Overview

The goal of this clinical trial is to determine the effect of treatment frequency on the physical recovery of adults with incomplete spinal cord injury. The treatment will last for eight weeks and will occur either either two or three times weekly. The main research questions are: 1. How do changes in muscle strength compare between participants who receive eight weeks of blood flow-restricted exercise two times vs. three times weekly? 2. How do changes in the level of independence performing a selected functional task compare between participants who receive eight weeks of treatment two times vs. three times weekly? 3. How do changes in the perceived exertion needed to perform a functional task compare between participants who receive eight weeks of treatment two times vs. three times weekly? The researchers will compare people receiving treatment two vs. three times per week to see if they differ in the amount of change seen in muscle strength, level of independence performing a functional task requiring use of the targeted muscle group, and/or perceived exertion required to perform the functional task. Participants will: 1. complete three pre-treatment evaluation sessions to establish muscle strength, level of independence performing a functional task, and perceived exertion required to perform a functional task. 2. perform four sets of 20 muscle contraction repetitions of blood flow-restricted exercise on the left and right sides of the body using the targeted muscle group either two times or three times weekly depending on treatment group assignment. 3. complete three post-treatment evaluation sessions to establish muscle strength, level of independence performing a functional task, and perceived exertion required to perform a functional task.

Participants in both treatment groups will receive blood flow-restricted (BFR) intervention for eight weeks. Other than substituting BFR exercises for those typically performed with the target muscle group, a participant's established treatment program will not change with study enrollment. Participants will engage in pre-treatment data collection measuring the strength and functional use of the target muscle group for three consecutive days before beginning the BFR protocol. We will use a dynamometer to measure in Newtons the maximum force a participant can exert with the left and right target muscle. To measure functional use, we will assess the assistance a participant needs to perform a designated functional task using the Functional Independence Measure (FIM) rating scale. Participants will rate their perceived effort with the Borg category-ratio 10 Rating of Perceived Exertion (Borg) scale. Each BFR exercise session will begin with measuring resting blood pressure to ensure it is between 80/50 mmHg and 150/90 mmHg. We will then place a 50% inflated pneumatic cuff either with or without an electrical stimulation (ES) device, as appropriate, on the participant's target limb. The participant will perform 4 sets of 20 low-dose contractions of the target muscle with 30 s rest between sets. We will only use ES supplementation when a participant can not perform additional set repetitions independently. Resistance band placement will increase repetition difficulty as strength increases. The treatment regimen will then repeat with the contralateral limb. We will repeat the measurement of muscle strength and functional task performance for three consecutive days at the conclusion of the eight-week treatment regimen. Again, we will rate the assistance provided for functional task performance using the FIM scale, and the participant will report the effort exerted using the Borg scale.