Porter 2014 Abstract IOC95

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Porter C (2014) The impact of resistance exercise training on skeletal muscle mitochondrial respiration in healthy young adults. Mitochondr Physiol Network 19.10

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Porter C, Reidy PT, Bhattarai N, Sidossis LS, Rasmussen BB (2014)

Event: IOC95

Purpose: The impact of aerobic exercise on skeletal muscle bioenergetics is well documented. In contrast, little is known concerning the impact of resistance exercise (RE) on skeletal muscle mitochondrial function. As such, our aims were to determine the impact of a 12-week RE program on skeletal muscle mitochondrial function. Methods: Biopsies from the m. vastus lateralis were collected from 11 young healthy men before and after a 12-week RE training program. High resolution respirometry was used to determine maximal leak (L), coupled (P) and uncoupled (E) mitochondrial respiration in permeabilized myofiber bundles. Results: RE increased maximal coupled skeletal muscle mitochondrial respiration (P) by 37% (55±7 vs. 75±6 pmol/mg/sec, P<0.01). Maximal uncoupled respiration (E), a marker of oxidative capacity, was also significantly increased by RE (64±5 vs. 104±10 pmol/mg/sec, P<0.001). P and E were positively correlated both pre (r=0.97, P<0.001) and post (r=0.92, P<0.001) RE. The respiratory control ratio for ADP was not different pre and post RE. The substrate control ratio (SCR) for succinate decreased after RE (1.79±0.12 vs. 1.25±0.05, P<0.001). The flux control ratio (FCR) for complex I of the electron transport chain (P/E) increased after RE (0.48±0.04 vs. 0.60±0.04, P<0.05). Conclusions: RE significantly increases coupled mitochondrial respiration in skeletal muscle. As increased P was accompanied by increased E, suggests that increased oxidative capacity was responsible for quantitative changes in P. With that said, the SCR for the complex II substrate succinate was reduced following RE, while the FCR (P/E) when respiration was supported by complex I substrates was increased after RE. This suggests that RE results in qualitative alterations in skeletal muscle mitochondrial function, where electron transfer through complex I makes a greater contribution to P. Collectively, our data demonstrate that a 12-week RE program results in qualitative and quantitative alterations in skeletal muscle mitochondria.


O2k-Network Lab: US TX Galveston Porter C, US TX Galveston Sheffield-Moore M


Labels: MiParea: Respiration, Exercise physiology;nutrition;life style 


Organism: Human  Tissue;cell: Skeletal muscle  Preparation: Permeabilized tissue 


Coupling state: LEAK, OXPHOS, ET 

HRR: Oxygraph-2k