Comparison of electromyographic activity of the gluteal muscles and tensor fascia lata in persons with patellofemoral pain: evaluation of selected, hip-targeted exercises using indwelling fine-wire electrodes.
Level 4 - case-series / case-control
Cross-sectional laboratory study evaluating muscle activation within a single clinical cohort.
PubMed 37212292 · doi:10.1080/09593985.2023.2215389
What was done
Electromyographic (EMG) activity of the gluteus medius (GMED), superior gluteus maximus (SUP-GMAX), and tensor fasciae latae (TFL) was measured using indwelling fine-wire electrodes in 12 individuals with patellofemoral pain (PFP). Participants performed 11 hip-targeted exercises. Normalized EMG activity (%MVIC) of the gluteal muscles was compared to TFL activity across exercises using repeated measures ANOVAs and descriptive statistics.
What was found
Only the clam exercise with elastic resistance elicited significantly greater activation in both gluteal muscles relative to the TFL (SUP-GMAX = 24.2 ± 14.4%MVIC, p = .05; GMED = 37.2 ± 19.7%MVIC, p = .008; TFL = 12.5 ± 11.7%MVIC). Five exercises produced significantly lower activation of SUP-GMAX relative to TFL: unilateral bridge (SUP-GMAX 17.7 ± 9.8% vs TFL 34.0 ± 17.7%, p = .01), bilateral bridge (SUP-GMAX 10.0 ± 6.9% vs TFL 14.0 ± 7.5%, p = .04), abduction (SUP-GMAX 14.2 ± 11.1% vs TFL 33.0 ± 11.9%, p = .001), hip hike (SUP-GMAX 14.8 ± 12.8% vs TFL 46.8 ± 33.7%, p = .008), and step-up (SUP-GMAX 15.0 ± 5.4% vs TFL 31.7 ± 19.9%, p = .02). The other 6 exercises showed no significant differences (all p > .05).
Why it matters
Clinicians cannot assume all standard hip-strengthening exercises preferentially target the gluteals over the TFL in patients with patellofemoral pain. Among 11 tested movements, only the resisted clam preferentially recruited the gluteal muscles over the internal rotator TFL.
Limits
The study had a very small sample size (n = 12) and lacked a healthy control group. It evaluated acute electromyographic amplitude during single sessions rather than long-term clinical outcomes such as strength gains, kinematics, or pain reduction.
Cited by
- supports Lateral hip abduction exercises target and develop the gluteus medius, gluteus minimus, and the upper subdivision of the gluteus maximus.