The aim was to investigate the effects of different volumes of strength training (ST) in association with photobiomodulation (PBMt) in mice fed a high-fat diet (HFD) on insulin resistance (IR). Male Swiss albino mice were fed HFD and performed high- or low-volume (one-third) ST (3 days/week), associated with PBMt (660 nm + 850 nm; ~42 J delivered) or not (lights off). ST improved IR, lowered visceral adiposity and circulating cytokines, and increased skeletal muscle hypertrophy and mitochondrial activity. The smaller volume of ST did not interfere with the improvement in IR, mitochondrial activity, or inflammatory profile, but exerted a smaller effect on visceral adiposity and skeletal muscle hypertrophy. Association with PBMt further improved IR, regardless of ST volume, although it did not affect adiposity, mitochondrial activity, and the inflammatory profile. Interestingly, PBMt positively affected quadriceps, but attenuated gluteus maximus hypertrophy. The association with PBMt induced greater improvement than ST alone.

Currently, an increasing number of studies about systemic laser photobiomodulation (FBM), have been highlighted in the literature; however, they differ in their application methods, which can be intravenous (intravascular laser irradiation of blood), or transdermally, (vascular photobiomodulation). This review aimed to compile all findings on these techniques and critically discuss their results. A search for articles was conducted in the PubMed, Scopus, and Web of Science databases. After applying inclusion and exclusion criteria, 37 articles were selected. Of these, 19 studies discussed the use of systemic FBM with intravenous application, and 7 studies reported transcutaneous application. Regarding clinical studies, 28 studies addressed the application of the techniques in respiratory, cardiovascular, metabolic, neurological, and musculoskeletal conditions. For preclinical studies, 9 articles primarily discussed the application in pulmonary and musculoskeletal conditions. Despite the promising results, methodological limitations and variabilities in studies on systemic laser FBM prevent the categorical assertion of its efficacy.