Gluteus medius muscle activity in patellofemoral pain syndrome during squats: A Systematic Review.

Background: Pain around or behind the patella during activities like running, climbing stairs, jumping or squatting is termed as Patellofemoral pain syndrome (PFPS). The causes of PFPS are multifactorial. An improper gluteal muscle function may cause an increment in hip joint adduction and internal rotation movement during weight-bearing activities is one of the major causes of PFPS.

Objective: To analyze Gluteus medius activity in PFPS during squats.

Method: PubMed, SCOPUS, PEDro, Science direct, and Web of Science databases were searched. The methodological quality was evaluated using the downs and black scale. Observational and experimental studies were included.

Results: Seven studies were included in this systematic review. The main findings were in favour of previous studies showing significant reduction in levels of Gluteus medius muscle activation in PFPS population during the different weight-bearing activities. Overall, we found significant reduction in Gluteus medius activity during squats with one exception showing non-significant results (effect size <0.2). We also found increased vastus medialis oblique (VMO) and vastus lateralis (VL) activity during squats in PFPS. However, we observed non-significant findings for gluteus maximus (GMax) muscle activity.

Conclusion: This systematic review supports the evidence indicating GMed activity showing moderate to strong relationship with weight-bearing activities like squatting with PFPS. There is a need of more studies, as very few studies are available to conclude about the Gluteus medius activity.