The Sex-Specific Impact of a Single Foam Rolling Session on Peripheral Muscle Oxygenation in Recreational Adults With Hamstring Tightness

The hamstring muscle is a biarticular muscle that simultaneously contributes to both hip extension and knee flexion movements. From the perspective of myofascial continuity, the hamstring is part of the Superficial Back Line, whose general postural function is to support the body in a fully upright position and to prevent the tendency toward flexion. This continuous postural role throughout the day necessitates a higher proportion of slow-twitch, endurance-oriented muscle fibers within the muscular segments of this myofascial chain. The hamstrings, as components of this line, maintain a low-level but sustained tone during the day to support posture.

Tightness in the hamstring muscles frequently arises due to issues in structural connectivity such as segmental shortening or tension along the Superficial Back Line, prolonged postural loading, imbalances with the Superficial Front Line, or alterations in pelvic tilt. It has been demonstrated that hamstring tightness can lead to alterations in gait patterns, low back pain, patellar tendinopathy, plantar fasciitis, and hamstring injuries.

Hamstring flexibility is a fundamental factor for individuals to enhance their sports performance and maintain a healthy lifestyle. Achieving adequate range of motion or flexibility not only supports the optimal functioning of the musculoskeletal system but also contributes to the prevention of injuries and muscular imbalances. One of the methods employed to improve hamstring flexibility is myofascial release. According to a meta-analysis examining the immediate effects of myofascial release applied along the Superficial Back Line in adults, the majority of studies have reported improvements in joint range of motion (ROM) and muscle flexibility.

One technique known as self-myofascial release is the use of a foam roller. A foam roller is a rigid cylindrical tool made of foam, available in various densities and sizes. The pressure applied with a foam roller stimulates the Golgi tendon organ, thereby reducing muscle tension. Another possible effect is the enhancement of tissue hydration; during application, the soft tissues are compressed like a sponge, allowing fluids to permeate the tissues, facilitating movement between fascial layers, and increasing blood flow and tissue temperature. Additionally, it is hypothesized that foam rolling helps release fascial adhesions and reduces scar tissue formation.

The physiological properties of connective tissues differ between males and females. Women are generally considered to be more flexible compared to men and structurally demonstrate greater tissue compliance, exhibiting a higher capacity to stretch or adapt to deformation. Therefore, the effects observed following foam roller application may vary between sexes. One study sought to investigate the sex-specific effects of acute self-myofascial release on joint range of motion and muscle stiffness. Following a foam roller intervention consisting of two sets of 30 seconds, no significant difference was observed in soft tissue stiffness or joint range of motion among female participants; however, significant improvements were noted in the male group regarding plantar flexion, dorsiflexion, and plantar flexion range of motion. Analysis of covariance comparing sex differences revealed significant differences between groups in the medial region of the Achilles tendon and gastrocnemius muscle. These findings suggest that short-duration self-myofascial release sessions may be sufficiently effective in increasing ankle joint range of motion in males; however, further research is needed to generalize these results to females. Due to inconclusive findings regarding soft tissue stiffness across sexes, larger sample sizes are recommended to explore this topic further.