Surface electromyography (sEMG) can be used as a biofeedback (BFB) parameter to provide information to participants regarding muscle activation in a variety of settings. The objective of our study is to assess whether an sEMG BFB display during physical therapy sessions for acute spinal cord injured inpatients would assist in increasing muscle use and patient engagement during therapy. In addition, we sought to assess whether the therapist and patients would find the sEMG BFB relevant and useful. To achieve this objective, we examined the effect of visual sEMG BFB system in improving muscle activation and therapeutic outcomes during experimental sessions that mimicked conventional slings therapy sessions with a research therapist providing the therapy. We recruited two inpatients with recent spinal cord injuries (SCI) that had been prescribed (clinical) slings therapy as part of their clinical standard of care at our acute rehabilitation hospital. During each experimental session there were two portions. One was the control period which required the participants to repeat elbow flexion 10 times under conventional clinical slings therapy protocols. The other was the BFB period, where the therapist guided the participant in the same movement but both therapist and the participant were provided with visual feedback of real-time sEMG signals recorded from participant's biceps brachii muscles. Our preliminary results show that both participants demonstrated statistically significant improvement of muscle activation level with the sEMG BFB system compared with conventional clinical slings therapy protocols.