Author(s)

Jasmin K. Ma, Trisha D. Scribbans, Brittany A. Edgett, J. Colin Boyd, Craig A. Simpson, Jonathan P. Little, Brendon J. Gurd

Department of Emergency Medicine, Kingston General Hospital, Kingston, Canada.
Department of Health and Social Development, University of British Columbia Okanagan, Kelowna, Canada.
Department of Kinesiology, Queen’s University, Kingston, Canada.

Purpose: The purpose of the present study was to evaluate whole-muscle content of several proteins involved in the regulation of skeletal muscle mitochondrial protein content and anaerobic capacity following 4 weeks of extremely low-volume high-intensity interval training (HIT). Methods: Young, healthy, recreationally active adult males (n = 8) trained 4 times a week for 4 weeks on a cycle ergometer. Each session involved 4 min of total exercise comprised of eight 20 s intervals at ~170% of peak aerobic power separated by 10 s rest. Muscle biopsies were taken prior to (pre) and ~72 hrs post-training (post). Par- ticipants completed an incremental peak oxygen up- take (VO₂peak) test and a Wingate test pre-, mid-, and post-training. Results: VO₂peak was elevated (p < 0.05) at mid- (p < 0.05) and post-training (pre: 40.5 ± 3.8 ml·kg^-1·min^-1, mid: 43.4 ± 2.5 ml·kg^-1·min^-1, post-: 47.2 ± 2.9 ml·kg^-1·min^-1). Wingate mean power also increased with training (pre-: 701.0 ± 73.0 W, mid-: 745.5 ± 73.3 W, post-: 786.8 ± 80.0 W). While maximal citrate synthase activity was unchanged, protein expression of the mitochondrial protein cytochrome c oxidase (COX) subunit I (+27%; p < 0.05) and COX IV (+26%; p < 0.05), PDK2 (+28%; p = 0.08) increased. Increases (p < 0.05) in both total PGC-1α (+19%), and nuclear PGC-1α (+46%) were also observed after 4 weeks of HIT. No changes were observed in the whole-muscle contents of PDHe1a, PDK4, SIRT1, mTOR, S6K1, MCT1, or PFK protein. Conclusions: These results demonstrate that several mitochondrial protein (but not citrate synthase activity), PGC-1α protein content, and exercise capacity can be improved in only 4 min of total training time per day, 4 days per wk using HIT cycle training.

PGC-1α; Mitochondrial Biogenesis; High-Intensity Interval Training; SIRT1; Aerobic Fitness

K. Ma, J. , D. Scribbans, T. , A. Edgett, B. , Colin Boyd, J. , A. Simpson, C. , P. Little, J. and J. Gurd, B. (2013) Extremely low-volume, high-intensity interval training improves exercise capacity and increases mitochondrial protein content in human skeletal muscle. Open Journal of Molecular and Integrative Physiology, 3, 202-210. doi: 10.4236/ojmip.2013.34027.