Hold it! Isometric exercise can change pain and strength in patellar tendinopathy.
Patellar tendinopathy is a condition that causes anterior knee pain, muscle inhibition and activity limitations. Tendinopathy is commonly treated with eccentric exercise; however, this can often be painful to complete. New research is suggesting a rehab program begin with isometric exercise.
A recent study compared isometric and isotonic exercise in male athletes with patellar tendinopathy. Immediately after a bout of isometric exercise there was a reduction in tendon pain and increase in maximal voluntary contraction for up to 45 minutes. When comparing to isotonic exercise, decrease in pain during a single-leg decline squat was significantly better in the isometric group. Increase in maximal voluntary contraction was only present in the isometric group. In addition, the group that completed isometric exercise had a reduction of cortical inhibition of the rectus femoris muscle, as measured by transcranial magnetic stimulation. Exercise criteria used in this study was isometric knee extension of 5 repetitions, 45 second hold, 70% of maximum voluntary contraction, knee held in 60 degrees flexion and 2 minutes rest between sets1.
As isometric exercise may have the ability to modulate pain and increase strength in patellar tendinopathy, it is suggested as a useful tool for irritable presentations of this condition. Isotonic exercise and progressive loading of the tendon is recommended as someone is able to complete these exercises without having increased pain and/or stiffness lasting longer than 24 hours2. Limited by a small sample size, further research is needed to determine whether these findings can be generalized to other populations and tendinopathy in other areas of the body.
1. Rio E, Kidgell D, Purdam C, Gaida J, Moseley G L, Pearce A J, Cook J. Isometric exercise induces analgesia and reduces inhibition in patellar tendinopathy. Br J Sports Med 2015; 49:1277-1283.
2. Malliaras P, Cook J, Purdam C, Rio E. Patellar tendinopathy: Clinical diagnosis, load management, and advice for challenging case presentations. J Orthop Sports Phys Ther. 2015; 45: 887-898.