Effect of short-term sprint interval training on human skeletal muscle carbohydrate metabolism during exercise and time-trial performance.
Our laboratory recently showed that six sessions of sprint interval training (SIT) over 2 wk increased muscle oxidative potential and cycle endurance capacity (Burgomaster KA, Hughes SC, Heigenhauser GJF, Bradwell SN, and Gibala MJ. J Appl Physiol 98: 1895-1900, 2005). The present study tested the hypothesis that short-term SIT would reduce skeletal muscle glycogenolysis and lactate accumulation during exercise and increase the capacity for pyruvate oxidation via pyruvate dehydrogenase (PDH). Eight men [peak oxygen uptake (VO2 peak)=3.8+/-0.2 l/min] performed six sessions of SIT (4-7x30-s "all-out" cycling with 4 min of recovery) over 2 wk. Before and after SIT, biopsies (vastus lateralis) were obtained at rest and after each stage of a two-stage cycling test that consisted of 10 min at approximately 60% followed by 10 min at approximately 90% of VO2 peak. Subjects also performed a 250-kJ time trial (TT) before and after SIT to assess changes in cycling performance. SIT increased muscle glycogen content by approximately 50% (main effect, P=0.04) and the maximal activity of citrate synthase (posttraining: 7.8+/-0.4 vs. pretraining: 7.0+/-0.4 mol.kg protein -1.h-1; P=0.04), but the maximal activity of 3-hydroxyacyl-CoA dehydrogenase was unchanged (posttraining: 5.1+/-0.7 vs. pretraining: 4.9+/-0.6 mol.kg protein -1.h-1; P=0.76). The active form of PDH was higher after training (main effect, P=0.04), and net muscle glycogenolysis (posttraining: 100+/-16 vs. pretraining: 139+/-11 mmol/kg dry wt; P=0.03) and lactate accumulation (posttraining: 55+/-2 vs. pretraining: 63+/-1 mmol/kg dry wt; P=0.03) during exercise were reduced. TT performance improved by 9.6% after training (posttraining: 15.5+/-0.5 vs. pretraining: 17.2+/-1.0 min; P=0.006), and a control group (n=8, VO2 peak=3.9+/-0.2 l/min) showed no change in performance when tested 2 wk apart without SIT (posttraining: 18.8+/-1.2 vs. pretraining: 18.9+/-1.2 min; P=0.74). We conclude that short-term SIT improved cycling TT performance and resulted in a closer matching of glycogenolytic flux and pyruvate oxidation during submaximal exercise.
Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada L8S 4K1.
Kirsten A
KA
Burgomaster
George J F
GJ
Heigenhauser
Martin J
MJ
Gibala
D000328:Adult; D050260:Carbohydrate Metabolism / Q000502:physiology*; D016022:Case-Control Studies; D002950:Citrate (si)-Synthase / Q000032:analysis / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006003:Glycogen / Q000032:analysis / Q000378:metabolism; D050261:Glycogenolysis / Q000502:physiology*; D006801:Humans; D007773:Lactates / Q000032:analysis / Q000378:metabolism; D008297:Male; D008931:Mitochondria, Muscle / Q000201:enzymology; D018482:Muscle, Skeletal / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D011768:Pyruvate Dehydrogenase Complex / Q000032:analysis / Q000502:physiology; D012420:Running / Q000502:physiology*; D013997:Time Factors
D007773:Lactates; D011768:Pyruvate Dehydrogenase Complex; D006003:Glycogen; D002950:Citrate (si)-Synthase