Trial of Self-managed Approaches for Patellofemoral Pain Syndrome in Active Duty

All participants will receive a standard home-based exercise rehabilitation protocol for PFPS. HEP teaches muscle strengthening exercises and self-management strategies to prevent recurrence. This program includes sessions with the study coordinator. A handout and given a demonstration of the daily exercises to be performed at home and weekly communication from the study coordinator regarding compliance with the exercises.

To ensure consistent interventions across participants, a specified percentage of baseline maximal voluntary contraction (% MVC) will be used to determine the intensity of the training contraction. The electrical amplitude to obtain the desired intensity will be determined for each participant. Participants will train at 20-30% of MVC during weeks 1-3, 30-40% of MVC during weeks 3-6, and 40-50% of MVC during weeks 6-9. Incremental increases will be made at the 3 and 6 week clinic visits. Individualized instructions for adjusting the amplitude dial settings, with a return demonstration, will be used to maintain the appropriate percentage of MVC. During the home training sessions, participants will adjust the amplitude required to achieve the desired goal, as tolerated.

The TENS protocol consists of 20-minutes of TENS stimulation while concurrently performing the HEP. The TENS with HEP and HEP alone will be alternated for 9 weeks. The Active device delivers a pre-set program of pulsed electrostimulation using a patented asymmetrical simple modulated pulse (SMP) waveform. SMP delivers a group of pulses as a repeating 12-second cycle.