Effects of high frequency strengthening on pain sensitivity and function in female runners with chronic patellofemoral pain

Objective

To investigate the effects of a high frequency strengthening program on function, pain, and pain sensitization in female runners with chronic patellofemoral pain (PFP).

Design

Cross-sectional study.

Setting

University laboratory.

Participants

Thirty female runners (mean age 32 ± 8.1 years) with chronic PFP completed an 8-week home strengthening program.

Main outcome measures

Variables assessed at baseline, 8-weeks, and 12 weeks included single leg step down test (SLSD), pain, Anterior Knee Pain Scale (AKPS), University of Wisconsin Running Injury and Recovery Index (UWRI), and quantitative sensory testing.

Results

There was large and statistically significant improvement at 8 and 12 weeks for average knee pain (η_p² = 0.334, p < 0.001), worst knee pain (η_p² = 0.351, p < 0.001), SLSD (η_p² = 0.161, p = 0.001), AKPS (η_p² = 0.463, p < 0.001), and UWRI (η_p² = 0.366, p < 0.001). A medium to large effect and statistically significant improvement in pressure pain threshold testing was found for all local and remote structures (η_p² range, 0.110 to 0.293, range p < 0.001 to p = 0.009) at 8 and 12 weeks.

Conclusions

There was a significant decrease in local and remote hyperalgesia via mechanical and thermal pain sensitivity testing in female runners with chronic PFP. There was a large effect and significant improvement in self-reported pain and function.