Glänzel, MH, Rodrigues, DR, Petter, GN, Pozzobon, D, Vaz, MA, and Geremia, JM. Foam rolling acute effects on myofascial tissue stiffness and muscle strength: a systematic review and meta-analysis. J Strength Cond Res 37(4): 951–968, 2023—Foam rolling (FR) is widely used in rehabilitation and physical training. However, the effects of FR on myofascial tissue stiffness and muscle strength remain unclear. This study aimed to perform a systematic review with meta-analysis of trials that tested the FR acute effects during warm-up on the myofascial tissue stiffness and muscle strength in healthy adults or athletes. This systematic review (CRD42021227048) was performed according to Cochrane's recommendations, with searches performed in PubMed, Web of Science, Embase, and PEDro databases. Syntheses of included studies' data were performed, and the PEDro scale was used to assess the methodological quality of the studies. Certainty of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluations approach. Twenty included studies assessed trunk and thigh fascial tissue stiffness, and thigh and calf muscle stiffness, whereas muscle strength was assessed in the knee extensors and flexors, and plantar flexors muscles. Qualitative analysis showed decreases in fascial (n = 2) and muscle (n = 5) stiffness after FR. However, the meta-analysis showed no effects of FR on myofascial tissue stiffness. Both qualitative and quantitative analyses showed no effects of FR on isometric muscle strength, eccentric torque, and rate of force development. However, the knee extensor concentric torque increased after FR. Foam rolling increases the knee extensor concentric torque, but it does not acutely change the myofascial tissue stiffness and isometric muscle strength. However, evidence of these studies provides low certainty to state that FR does not change these parameters. Therefore, high methodological quality studies should be performed to better ascertain the effects of FR on the myofascial tissue stiffness and muscle strength.

BACKGROUND AND OBJECTIVES: This study is necessary considering the expressive number of rural workers that are not assisted by a health professional despite the presence of musculoskeletal changes such as low back pain. Thus, the objective was to check if there is a relationship among low back pain levels, anthropometric measures and range of motion of rural workers. METHODS: A cross-sectional study with rural workers that used the visual analog scale to measure low back pain. The data on body mass index, fat percentage, waist circumference, waisthip ratio and visceral fat area were obtained, as well as the assessment of posterior chain range of motion. RESULTS: Fifty-five rural workers were evaluated, with a predominance of women and married. Of the subjects evaluated, 37 (67.3%) reported low back pain, with an average pain of 3.4±2.7. More than half of the sample presented values of body mass index, fat percentage, waist circumference and waist-hip ratio considered undesirable. Those with pain had higher values of body mass index and visceral fat area. CONCLUSION: Rural workers with low back pain presented higher values of body mass index and visceral fat area, as well as those with an inadequate range of motion in the same region who had higher values of visceral fat area and pain. It is also possible to infer that there is an association between the values of body mass index and visceral fat area with the level of pain, just as the waisthip ratio is associated with the levels of the range of motion.

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