Effects of Foam Rolling on Plantar Flexor Recovery in Healthy Individuals

Foam rolling (FR) is a self-myofascial release technique that involves using body weight to apply pressure to soft tissues through a foam roller. This technique has been widely used in rehabilitation and physical training settings, aiming at the treatment of myofascial dysfunctions, enhancement of physical performance, and recovery from exercise-induced muscle damage (EIMD). EIMD occurs following the performance of intense exercise, resulting in increased muscle stiffness and delayed onset muscle soreness (DOMS), as well as reductions in force production and range of motion (ROM).

However, few studies have investigated the effects of FR on the recovery of musculotendinous and functional properties. Although there is evidence suggesting a reduction in muscle stiffness, this finding does not appear to be consistent across the literature. Furthermore, no studies have been identified that evaluated the effects of FR on the recovery of fascial and tendinous tissues. Regarding functional properties, although FR application may promote improved recovery of DOMS, ROM, vertical jump performance, and muscle strength, contradictory findings have been reported.

Therefore, the aim of the present study is to investigate the effects of FR on the recovery of musculotendinous and functional properties of plantar flexors in healthy individuals. A total of 69 healthy male participants, aged between 18 and 40 years, will be included in the study. Participants will undergo an EIMD protocol using an isokinetic dynamometer and will be randomly assigned to either the FR (self-myofascial release with FR: 3 sets of 30 s) or a control group (CON; rest for 90 s).

The mechanical properties of the myofascial tissues of the triceps surae and the Achilles tendon (AT) will be assessed using shear wave elastography, while echo intensity (EI) of the triceps surae will be obtained through grayscale analysis of ultrasound (US) images. DOMS will be assessed using a visual analog scale. Maximum dorsiflexion ROM, peak torque production (isometric and isokinetic), and rate of torque development of the plantar flexors will be evaluated using the isokinetic dynamometer. Drop jump performance will be assessed using a force platform.

Ultrasound imaging will also be used to determine cross-sectional area, resting length, and deformation of the AT during maximal voluntary isometric contractions. Based on these data, force-deformation and stress-strain relationships of the AT will be determined.

Assessments will be conducted before (Pre-1 and Pre-EIMD), immediately after the EIMD protocol (Post-EIMD), and at 24 h (Post-24h), 48 h (Post-48h), and 72 h (Post-72h) following the interventions (FR or CON). Descriptive statistics (mean, standard deviation, and standard error) will be used to present the results. Reliability of US measurements, as well as data normality and sphericity, will be assessed. A two-way ANOVA (group × time) will be used for comparisons, followed by Bonferroni post hoc tests to identify differences. Additionally, effect sizes will be calculated for each intervention, and correlation analyses will be performed to examine the influence of adipose tissue thickness on the evaluated parameters.