אימונים Concurrent resistance and aerobic exercise stimulates both myofibrillar and mitochond

[Mike Bikov]

J Appl Physiol. 2012 Apr 5. [Epub ahead of print]
Concurrent resistance and aerobic exercise stimulates both myofibrillar and mitochondrial protein synthesis in sedentary middle-aged men.
Donges CE, Burd NA, Duffield R, Smith GC, West DW, Short MJ, Mackenzie RW, Plank LD, Shepherd PR, Phillips SM, Edge JA.
Source
1Charles Sturt University.
Abstract
We determined myofibrillar and mitochondrial protein fractional synthesis rates (FSR), intramuscular signalling protein phosphorylation, and mRNA expression responses after isolated bouts of resistance exercise (RE), aerobic exercise (AE), or in combination (termed concurrent exercise; CE) in sedentary middle-aged men. Eight subjects (age=53.3±1.8y; BMI=29.4±1.4 kg(.) m(2)) randomly completed 8×8 leg extension repetitions at 70% of one repetition-maximum, 40min cycling at 55% peak aerobic power output (AE), or (consecutively) 50% of the RE and AE trials (CE). Biopsies were obtained (during a primed, constant infusion of L-[ring-(13)C(6)]phenylalanine) while fasted, and at1h and 4h following post-exercise ingestion of 20g of protein. All trials increased mitochondrial FSR above fasted rates (RE=1.3-fold; AE=1.5; CE=1.4) (P<0.05); although, only CE (2.2) and RE (1.8) increased myofibrillar FSR (P<0.05). At 1h post-exercise, phosphorylation of Akt on Ser(473) (CE=7.7; RE=4.6) and Thr(308) (CE=4.4; RE=2.9), and PRAS40 on Thr(246) (CE=3.8; AE=2.5) increased (P<0.05); with CE greater than AE for Akt Ser(473)-Thr(308) and greater than RE for PRAS40 (P<0.05). Despite increased phosphorylation of Akt-PRAS40, phosphorylation of mTOR (Ser(2448)) remained unchanged (P>0.05), whilst rpS6 (Ser(235/236)) increased only in RE (10.4) (P<0.05). CE and AE both resulted in increased PGC1α expression at 1h (CE=2.9; AE=2.8; P<0.05) and 4h (CE=2.6; AE=2.4), and PGC1β expression at 4h (CE=2.1; AE=2.6; P<0.05). These data suggest that CE induced acute stimulation of myofibrillar and mitochondrial FSR, protein signalling, and mRNA expression are equivalent to either isolate mode (RE or AE). These results occurred without an interference effect on muscle protein sub-fractional synthesis rates, protein signalling, or mRNA expression.​

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