The Effects of Protonics Knee Brace Versus Hamstring Resisted Exercise on Individuals With Patellofemoral Pain Syndrome

The Protonics system has been introduced to physical therapists as a potential treatment for PFPS. The system includes a brace set to resist knee flexion and a set of specific exercises to perform daily. Through resistance to knee flexion, the system is advertised to decrease retropatellar contact pressure due to changes in pelvis inclination and available hip rotation. Specifically, resistance to knee flexion is purported to increase hamstring activity and inhibit the activity of the tensor fasciae latae and psoas muscles. The manufacturer asserts that prolonged use of the system results in greater hamstring activation, which leads to permanent structural changes through reciprocal inhibition at the hip and pelvis. The warm-up consisted of the subject wearing the ProtonicsTM knee brace set at a moderate resistance level and flexing the knees while sitting, standing, and reclining in the supine and prone positions.

Subjects assigned to the sport cord group were asked to do the same warm-ups and exercises using the sport cord in the supine, standing, sitting, and prone positions. prone. The only difference is that subjects were asked to only walk backwards instead of forwards in order to avoid activation of the hip flexor muscle. The appropriate level of resistance for each subject was calculated by multiplying their weight in pounds by 0.3. Subjects were then given either light, medium, or heavy resistance cords according to the following classification scheme: light (pink color) with resistance 3 (R3), 0-30 lbs.; medium (orange color) with resistance 5 (R5) 0-50 lbs.; heavy (yellow color) with resistance 7 (R7) 0-70 lbs. All subjects completed three study visits, and a total of four measurements were taken at baseline, immediately following the first session, at two weeks, and at 4 weeks.