Abstract
PURPOSE: Resistance exercise training (RET) attenuates age-related muscle and strength loss ('sarcopenia'). However, compared with machine-based RET, the efficacy of cost-effective, accessible elastic band RET (EB-RET) for muscle adaptive remodelling lacks supporting mechanistic evidence.
METHODS: 8 young (YM; 24 ± 4 yrs) and 8 older (OM; 68 ± 6 yrs) untrained males consumed an oral stable isotope tracer (D2O) combined with serial vastus lateralis muscle biopsies to measure integrated myofibrillar protein synthesis (iMyoPS) and regulatory signalling over ~48 hrs prior to (habitual) and following an acute bout of EB-RET (6x12 repetitions at ~70% of one-repetition maximum). iMyoPS was determined via gas chromatography-pyrolysis-isotope ratio mass spectroscopy and regulatory signalling expression by immunoblot.
RESULTS: Habitual iMyoPS did not differ between YM and OM (1.62 ± 0.21 vs 1.43 ± 0.47%·day -1, respectively; P = 0.128). There was a significant increase in iMyoPS after EB-RET in YM (2.23 ± 0.69%day -1; P = 0.02), but not OM (1.75 ± 0.54%day -1; P = 0.30). EB-RET increased the phosphorylation of key anabolic signalling proteins similarly in YM and OM at 1 h post-exercise, including p-IRS-1Ser636/639, p-AktSer473, p-4EBP-1Thr37/46, p-P70S6KThr389 and p-RPS6Ser240/244, whereas p-TSC2Thr1462 and p-mTORSer2448 increased only in YM (all P < 0.05). There were no differences in the expression of amino acid transporters/sensors or proteolytic markers following EB-RET.
CONCLUSIONS: iMyoPS was elevated following EB-RET in YM but not OM. However, the increase in acute anabolic signalling with EB-RET was largely similar between groups. In conclusion, the capacity for EB-RET to stimulate iMyoPS may be impaired in older age. Further work may be necessary to optimise prescriptive programming in YM and OM.
Original language | English |
---|---|
Pages (from-to) | 398-408 |
Number of pages | 11 |
Journal | Medicine and Science in Sports and Exercise |
Volume | 55 |
Issue number | 3 |
Early online date | 18 Oct 2022 |
DOIs | |
Publication status | Published - Mar 2023 |