The safety of each training program was determined by the absence of adverse events, including the absence of a significant increase in shoulder pain measured with the WUSPI questionnaire (i.e., >5.10 points of the total score which corresponds to the minimal detectable change ).
Two participants in the HIIT group failed to complete all aspects of the study: one participant dropped out at the beginning of the project because he was involved in another training program and one participant dropped out due to a significant increase in shoulder pain after six training sessions (+19.2/150 on the WUSPI).
However, one dropout in the HIIT group was due to the development of significant shoulder pain (WUSPI score = 33.8/150) over the course of the training program.
Moreover, the participant who dropped out of the HIIT group because of shoulder pain was the one with the highest WUSPI score at baseline and was known for episodic increases in shoulder pain due to rotator cuff weakness.
Abbreviations: ANOVA = analysis of variance; C = cervical; EMG = electromyography, electromyographic; [EMG.sub.max] = maximum EMG value, [EMG.sub.transfer] = EMG data collected during transfers; HERL = Human Engineering Research Laboratories; [MUR.sub.EMG] = EMG muscular utilization ratio; %[MUR.sub.EMG] = percentage [MUR.sub.EMG]; MVC = maximal voluntary contraction; SCI = spinal cord injury; SD = standard deviation; sEMG = surface EMG; SPT = sitting pivot transfer; UL = upper limb; VA = Department of Veterans Affairs; WUSPI
= Wheelchair User's Shoulder Pain Index.