Effect of Resistance Training on Intermuscular Adipose Tissue in Older Adults at Risk of Mobility Limitations

Abstract

High levels of intermuscular adipose tissue (IMAT) in older adults are associated with muscle weakness and mobility limitations. This study determined if IMAT levels in older adults at risk of mobility limitations can be reduced following 12‐weeks of high‐load (HL)or low‐load blood flow restricted (BFR) resistance training. Twenty‐seven older adults (77.6 + 8.9 years; 27.3 +2.7 kg·m‐2) with low quadriceps muscle strength were randomly assigned to twice weekly sessions of HL (70% one repetition maximum, 1RM), BFR (30% 1RM coupled with a vascular restriction of 1.5 times systolic blood pressure at the proximal thigh) or attention control (CON) for 12‐weeks. HL and BFR groups engaged in three sets of leg extension, leg press, and leg curl training to muscular failure. The CON group performed light upper body resistance training that was not expected to result in muscle adaptations. T1 weighted magnetic resonance imaging scans were conducted to measure the volumes of skeletal muscle, subcutaneous adipose tissue (SAT), and IMAT in the thigh region before and after training. Following training, there were no differences in IMAT (P=0.22) and there were no differences in IMAT response between groups (P=0.38). SAT did not change over time (P=0.33) and there were no differences in SAT response between groups (P=0.39). Muscle volume significantly increased in the BFR group only (~5%; P=0.03) and was unchanged in the HL (~1.4%; P=0.18) and CON (~0.1; P=0.84). Twelve weeks of HL or BFR resistance training did not affect IMAT levels in older adults but it did improve muscle volume only after BFR training.Supported by NIH grant 1R15 A6040700‐01A1.