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Concurrent exercise incorporating high-intensity interval or continuous training modulates mTORC1 signaling and microRNA expression in human skeletal muscle

journal contribution
posted on 01.06.2016, 00:00 authored by Jackson FyfeJackson Fyfe, D J Bishop, Evelyn ZacharewiczEvelyn Zacharewicz, Aaron RussellAaron Russell, N K Stepto
We compared the effects of concurrent exercise, incorporating either high-intensity interval training (HIT) or moderate-intensity continuous training (MICT), on mechanistic target of rapamycin complex 1 (mTORC1) signaling and microRNA expression in skeletal muscle, relative to resistance exercise (RE) alone. Eight males (mean ± SD: age, 27 ± 4 yr; V̇o2 peak,45.7 ± 9 ml·kg−1·min−1) performed three experimental trials in a randomized order: 1) RE (8 × 5 leg press repetitions at 80% 1-repetition maximum) performed alone and RE preceded by either 2) HIT cycling [10 × 2 min at 120% lactate threshold (LT); HIT + RE] or 3) work-matched MICT cycling (30 min at 80% LT; MICT + RE). Vastus lateralis muscle biopsies were obtained immediately before RE, either without (REST) or with (POST) preceding endurance exercise and +1 h (RE + 1 h) and +3 h (RE + 3 h) after RE. Prior HIT and MICT similarly reduced muscle glycogen content and increased ACCSer79and p70S6KThr389phosphorylation before subsequent RE (i.e., at POST). Compared with MICT, HIT induced greater mTORSer2448and rps6Ser235/236phosphorylation at POST. RE-induced increases in p70S6K and rps6 phosphorylation were not influenced by prior HIT or MICT; however, mTOR phosphorylation was reduced at RE + 1 h for MICT + RE vs. both HIT + RE and RE. Expression of miR-133a, miR-378, and miR-486 was reduced at RE + 1 h for HIT + RE vs. both MICT + RE and RE. Postexercise mTORC1 signaling following RE is therefore not compromised by prior HIT or MICT, and concurrent exercise incorporating HIT, but not MICT, reduces postexercise expression of miRNAs implicated in skeletal muscle adaptation to RE.

History

Journal

American Journal of Physiology - Regulatory Integrative and Comparative Physiology

Volume

310

Issue

11

Pagination

R1297 - R1311

Publisher

AMER PHYSIOLOGICAL SOC

Location

United States

ISSN

0363-6119

eISSN

1522-1490

Language

English

Publication classification

C Journal article; C1 Refereed article in a scholarly journal

Copyright notice

2016, American Physiological Society