Different Effects of Foam Rolling on Passive Tissue Stiffness in Experienced and Nonexperienced Athletes.

CONTEXT: Foam rolling (FR) has been developed into a popular intervention and has been established in various sports disciplines. However, its effects on target tissue, including changes in stiffness properties, are still poorly understood. OBJECTIVE: To investigate muscle-specific and connective tissue-specific responses after FR in recreational athletes with different FR experience. DESIGN: Case series. SETTING: Laboratory environment. PARTICIPANTS: The study was conducted with 40 participants, consisting of 20 experienced (EA) and 20 nonexperienced athletes (NEA). INTERVENTION: The FR intervention included 5 trials per 45 seconds of FR of the lateral thigh in the sagittal plane with 20 seconds of rest between each trial. MAIN OUTCOME MEASURES: Acoustic radiation force impulse elastosonography values, represented as shear wave velocity, were obtained under resting conditions (t0) and several times after FR exercise (0 min [t1], 30 min [t2], 6 h [t3], and 24 h [t4]). Data were assessed in superficial and deep muscle (vastus lateralis muscle; vastus intermedius muscle) and in connective tissue (iliotibial band). RESULTS: In EA, tissue stiffness of the iliotibial band revealed a significant decrease of 13.2% at t1 (P ≤ .01) and 12.1% at t3 (P = .02). In NEA, a 6.2% increase of stiffness was found at t1, which was not significantly different to baseline (P = .16). For both groups, no significant iliotibial band stiffness changes were found at further time points. Also, regarding muscle stiffness, no significant changes were detected at any time for EA and NEA (P > .05). CONCLUSIONS: This study demonstrates a significant short-term decrease of connective tissue stiffness in EA, which may have an impact on the biomechanical output of the connective tissue. Thus, FR effects on tissue stiffness depend on the athletes' experience in FR, and existing studies have to be interpreted cautiously in the context of the enrolled participants.

Effects of Pre- and Post-Exercise Cold-Water Immersion Therapy on Passive Muscle Stiffness.

BACKGROUND: Cold-water immersion (CWI) has become a popular preventive, regenerative and performance-enhancing intervention in various sports. However, its effects on soft tissue, including changes of intramuscular stiffness, are poorly understood. The purpose of this study was to investigate the effect of CWI on muscle stiffness. PATIENTS/MATERIAL AND METHODS: Thirty healthy participants were included and divided into the three following groups (n = 10): 1) post-ESU group: exercise and CWI (post-exercise set-up); 2) control group: exercise without CWI (control condition); 3) pre-ESU group: CWI alone (pre-exercise set-up). Acoustic radiation force impulse (ARFI) elastography was conducted to assess tissue stiffness (shear wave velocity, SWV). Values obtained at resting conditions (baseline, t0) were compared to values post-exercise (t1, for post-ESU group and control group), post-CWI (t2, for post-ESU group and pre-ESU group; rest for control group) and to 60-min follow-up time (t3, for all groups). Data were assessed in superficial and deep muscle tissue (rectus femoris muscle, RF; vastus intermedius muscle, VI). RESULTS: For the post-ESU group (CWI post-exercise), there was no significant difference between the time points of measurements: exercise (t1: RF: 1.63 m/s; VI: 1.54 m/s), CWI (t2: RF: 1.63 m/s; VI: 1.53 m/s) and at 60-min follow-up (t3: RF: 1.72 m/s; VI: 1.61 m/s). In the control group, a significant decrease of SWV was found between baseline conditions at t0 and post-exercise (t1) at VI (VI: 1.37 m/s; p = 0.004; RF: 1.59 m/s; p = 0.084). For t2 and t3, no further significant changes were detected. Regarding the pre-exercise set-up (pre-ESU group), a significant decrease in SWV from baseline to t2 in VI (1.60 m/s to 1.49 m/s; VI: p = 0.027) was found. CONCLUSION: This study shows varying influences of CWI on muscle stiffness. Overall, we did not detect any significant effects of CWI on muscle stiffness post-exercise. Muscle stiffness-related effects of CWI differ in the context of a pre- or post-exercise condition and have to be considered in the implementation of CWI to ensure its potential preventive and regenerative benefits.

Accelerating Recovery from Exercise-Induced Muscle Injuries in Triathletes: Considerations for Olympic Distance Races.

The triathlon is one of the fastest developing sports in the world due to expanding participation and media attention. The fundamental change in Olympic triathlon races from a single to a multistart event is highly demanding in terms of recovery from and prevention of exercise-induced muscle injures. In elite and competitive sports, ultrastructural muscle injuries, including delayed onset muscle soreness (DOMS), are responsible for impaired muscle performance capacities. Prevention and treatment of these conditions have become key in regaining muscular performance levels and to guarantee performance and economy of motion in swimming, cycling and running. The aim of this review is to provide an overview of the current findings on the pathophysiology, as well as treatment and prevention of, these conditions in compliance with clinical implications for elite triathletes. In the context of DOMS, the majority of recovery interventions have focused on different protocols of compression, cold or heat therapy, active regeneration, nutritional interventions, or sleep. The authors agree that there is a compelling need for further studies, including high-quality randomized trials, to completely evaluate the effectiveness of existing therapeutic approaches, particularly in triathletes. The given recommendations must be updated and adjusted, as further evidence emerges.