title: Short-term high-intensity interval training improves phosphocreatine recovery kinetics following moderate-intensity exercise in humans.
abstract: Previous studies have shown that high-intensity training improves biochemical markers of oxidative potential in skeletal muscle within a 2-week period. The purpose of this study was to examine the effect of short-term high-intensity interval training on the time constant () of phosphocreatine (PCr) recovery following moderate-intensity exercise, an in vivo measure of functional oxidative capacity. Seven healthy active subjects (age, 21 +/- 4 years; body mass, 69 +/- 11 kg) performed 6 sessions of 4-6 maximal-effort 30 s cycling intervals within a 2-week period, and 7 subjects (age, 24 +/- 5 years; body mass, 80 +/- 15 kg) served as controls. Prior to and following training, phosphorous-31 magnetic resonance spectroscopy (31P-MRS; GE 3T Excite System) was used to measure relative changes in high-energy phosphates and intracellular pH of the quadriceps muscles during gated dynamic leg-extension exercise (3 cycles of 90 s exercise and 5 min of rest). A monoexponential model was used to estimate the of PCr recovery. The of PCr recovery after leg-extension exercise was reduced by 14% with high-intensity interval training (pretraining, 43 +/- 14 s vs. post-training, 37 +/- 15 s; p < 0.05) with no change in the control group (44 +/- 12 s vs. 43 +/- 12 s, respectively; p > 0.05). These findings demonstrate that short-term high-intensity interval training is an effective means of increasing functional oxidative capacity in skeletal muscle.
authors.affiliation: Department of Physiology, Michigan State University, East Landing, MI 48824, USA. sforbes@msu.edu
authors.forename: Sean C
authors.initials: SC
authors.lastname: Forbes
authors.forename: Jill M
authors.initials: JM
authors.lastname: Slade
authors.forename: Ronald A
authors.initials: RA
authors.lastname: Meyer
mesh_terms: D000328:Adult; D001642:Bicycling; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology; D010725:Phosphocreatine / Q000378:metabolism*; D010807:Physical Endurance / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D012016:Reference Values; D013334:Students; D013997:Time Factors; D055815:Young Adult
chemical_list: D010725:Phosphocreatine