How Self-Myofascial Release Impacts Posterior Muscular Chain Flexibility Over Time and Across Different Flexibility Levels

Self-Myofascial Release (SMR) is a popular technique employed by individuals ranging from gym-goers and athletes to health enthusiasts. The mechanism behind SMR’s efficacy includes temporary changes in fascial elasticity, increased local blood flow, reduced inflammation, and stimulation of mechanoreceptors to ease muscle and fascia tension.

The focus of a new study is on SMR’s impact on flexibility, a crucial aspect for sports performance, daily activities, and musculoskeletal health.

Acute effects of SMR on the posterior muscular chain have been extensively studied, showing increased flexibility across the entire chain and improved ankle and spine range of motion (ROM). However, research on the duration of these acute effects and their variations based on individuals’ flexibility levels remains limited. Understanding how long the benefits of SMR persist after application, especially in individuals with varying levels of flexibility, could significantly impact training regimens and pre-competition preparations.

This study aimed to measure the duration of SMR’s acute effects on flexibility, spanning one hour after the SMR procedure, and investigate whether these effects differ among groups categorized by their initial flexibility levels. The investigation focused on the plantar muscles of the feet and aimed to uncover whether SMR offers greater gains in range of motion for individuals with limited posterior muscular chain flexibility. This research provides valuable insights into optimizing the timing of SMR application in training and competition scenarios, catering to individual flexibility needs.

Thirty-six participants performed SMR using a rigid ball under the surface of both feet. Participants were tested with the Sit and Reach (S&R) test at four different times: before (T0), immediately after (T1), 30 (T2), and 60 (T3) minutes after the SMR intervention.  Participants were divided into subgroups based on their flexibility levels, and the SMR effects were evaluated immediately, 30 minutes, and 60 minutes after the intervention.

Key findings include:

1. Gender Differences: Male participants exhibited lower flexibility compared to females at all measurement points (before, straight after and up to 1 hour after).
2. Time-Dependent Flexibility Increase: In the entire sample, flexibility consistently increased over time, with statistically significant differences noted. This suggests that the effects of SMR on flexibility persisted for up to an hour.
3. Subgroup Analysis: Participants were divided into flexible (FG), average (AG), and stiff (SG) subgroups based on their baseline flexibility. Each subgroup exhibited different responses to SMR:
   • FG: Those with high flexibility did not show significant changes in flexibility over time after SMR.
   • AG: Participants with average flexibility demonstrated an initial increase in flexibility after SMR , which was maintained at T2 and T3.
   • SG: Individuals with low flexibility experienced a delayed response to SMR, with increased flexibility observed at 30 and 60 mins.
4. Practical Implications: The results suggest that SMR can be an effective tool to improve flexibility, especially for those with average or lower baseline flexibility levels. Flexible individuals may not benefit significantly from SMR in terms of flexibility enhancement.
5. Duration of SMR Effects: This study is the first to investigate the prolonged effects of SMR, showing that flexibility improvements persist for up to an hour after the intervention. This information could be valuable for planning training sessions that incorporate SMR to enhance flexibility.
6. Musculoskeletal and Fascial Mechanisms: The study proposes that SMR applied to the plantar surface of the feet stimulates mechanoreceptors in the fascia, leading to temporary facilitation of the entire posterior muscular chain due to the viscoelastic properties of the fascial connective tissue.

Limitations of the study include the absence of a control group, a relatively small sample size, and a focus on overall posterior muscular chain flexibility without analyzing specific muscle groups or joint range of motion. Additionally, the study did not investigate the time required to return to baseline flexibility levels after SMR.

The study recomments that that physical exercise practitioners should assess individuals’ flexibility before training, as the SMR procedure used in this work does not seem necessary in flexible individuals.