The Acute Effects of Foam Rolling the Rectus Femoris on Force
Production Asymmetry During a Double-Leg Squat
Hiro Boyas Homma,
Lily James, Sami Abdul Majid, Dr. Kendra Nelson
Department of Kinesiology, University of Redlands, Redlands, CA 92373
Contact Info: kendra_nelson@redlands.edu
Background
Can foam rolling prevent injury?
Myofascia is a network of connective tissue surrounding the musculoskeletal system. Restrictions in this tissue can cause asymmetries in movement and increase the risk of injury.1 Foam rolling is a widely accepted technique used to reduce restrictions and improve mobility; however, existing literature fails to investigate the possible benefits of foam rolling on performance. In addition, the literature fails to provide quantitative data and reproducible methods.2
This study aims to provide a standardized protocol and obtain quantitative data to analyze the effects of foam rolling the rectus femoris on asymmetry. The double-leg squat has served as a baseline functional movement in previous literature and provides an accessible way to analyze changes in force production.3 VALD ForceDecks track unilateral force production in both eccentric and concentric movements. These metrics allow within-subject comparisons before and after a standardized foam rolling intervention targeted at decreasing myofascial restrictions.
Methods
Sample: 21 University of Redlands Students
Setup:
Standardization: Scripted protocols were given throughout the study, including an instructional video on foam rolling. Control Group: Waited 5 min stationary.
Data Collection
Discussion
• Concentric asymmetry improvement in both the experimental and control groups may be due to neural priming rather than foam rolling.
• The rectus femoris may be more active in the eccentric phase than concentric, explaining why foam rolling improved asymmetry solely in the eccentric experimental group.
• While weight was identified as a covariate, there were varying effects between the subgroups.
• A notable limitation of this study is its small sample size and that participants presented low asymmetries prior to intervention.
• Key finding: There was a trend in asymmetry improvement during the eccentric phase in the experimental group due to foam rolling (p=0.096). This trend became significant when standardizing for weight (p=0.012, η² = 0.333).
• Both experimental and control groups showed improvement in concentric asymmetry (p<0.007).
• Weight
Conclusions
• Foam rolling the rectus femoris may acutely improve lowerextremity asymmetries during the eccentric phase of squatting, particularly in individuals with higher body mass.
Future Work:
• Increasing squat trials to 5 repetitions per participant may reduce the effects of intra-subject variability.
• To better understand the activation of the rectus femoris concentrically and eccentrically, a dynamometer could be used to isolate and verify its force production during movement.