Knee extensor electromyographic activity during different depths of squat exercise in strength training experienced adults: A Systematic Review

Abstract

B

ACKGROUND: Changes in range of motion during partial and deep squats can affect the electrical activity of the knee extensor muscles. There are results’ divergences between studies that evaluated the effects of deep and partial squats on the electrical activity of the knee extensor muscles.

AIM: To systematically review the literature on the electromyographic activity of the knee extensor muscles during partial and deep squat exercises in subjects with strength training experience.

METHOD: The search included MEDLINE (via Pubmed), Scielo, EMBASE, in addition to a manual search, until June 2023. Cross-sectional observational studies comparing partial squats (up to 90º of knee flexion) and deep squats (maximum knee flexion) that evaluated the electrical activation through surface electromyography in men and women with strength training experience were included. Methodological quality assessment was performed using the adapted Downs and Black tool, as suggested by the Cochrane Collaboration. 

RESULTS: Of the 636 articles identified, four studies were included. The included studies presented electromyographic values of the two squat variations. No difference was found in the activation of the rectus femoris, vastus medialis and vastus lateralis muscles between partial and deep squats. Regarding methodological quality, one study was classified as having moderate and the other three studies showing high methodological quality.

CONCLUSION: The similarity in the knee extensors’ electromyographic activation between partial and deep squat exercises in men and women with strength training experience suggests that both exercises can be used for recruiting these muscles during physical fitness activities.