Is it truly impossible to strengthen the vastus medialis in isolation from the entire quadriceps muscle group?

Abstract

Background: To date, no specific exercises have been designed to selectively strengthen the vastus medialis muscle. Therefore, the purpose of this research is to provide a clear answer to the question: Is it truly impossible to strengthen the vastus medialis independently of the entire quadriceps muscle group? Methods: Thirty-three females with lateral patellar compression syndrome were randomly divided into 2 groups: one focused on selective strengthening of the vastus medialis (n = 16) and the other on general strengthening of the quadriceps (n = 17). The intervention lasted 8 weeks. Muscles cross-sectional area and electrical activity were assessed using ultrasound and electromyography, respectively. Data analysis was done using independent and dependent t-tests. Results: In the selective strengthening group, significant increases were observed in the activity and cross-sectional area of the vastus medialis, as well as in the ratios of vastus medialis/vastus lateralis activity and cross-section from pre-to post-intervention (P < 0.01). In the general strengthening group, significant increases were noted in the cross-sectional area of the vastus lateralis and the activity of both muscles, with a greater increase in the vastus lateralis (P < 0.01). Conclusions: Contrary to previous evidence, our findings demonstrate that preferential activation and selective strengthening of the vastus medialis muscle, independent of the other quadriceps components, is achievable through the training protocol employed in this study.

Keywords

• Vastus medialis
• Quadriceps
• Selective strengthening
• Lateral patellar compression syndrome
• Muscle activity
• Cross-section