Effect of Basis™ and High Intensity Interval Training (HIIT) on Muscle Metabolism and Exercise Performance

Commencing some training sessions with reduced carbohydrate (CHO) availability has been shown to enhance skeletal muscle adaptations, but the effect on exercise performance is less clear. We examined whether restricting CHO intake between twice daily sessions of high-intensity interval training (HIIT) augments improvements in exercise performance and mitochondrial content. Eighteen active but not highly trained subjects (peak oxygen uptake [VO2peak] = 44 ± 9 ml/kg/min), matched for age, sex, and fitness, were randomly allocated to two groups. On each of 6 days over 2 weeks, subjects completed two training sessions, each consisting of 5 × 4-min cycling intervals (60% of peak power), interspersed by 2 min of recovery. Subjects ingested either 195 g of CHO (HI-HI group: ~2.3 g/kg) or 17 g of CHO (HI-LO group: ~0.3 g/kg) during the 3-hr period between sessions. The training-induced improvement in 250-kJ time trial performance was greater (p = .02) in the HI-LO group (211 ± 66 W to 244 ± 75 W) compared with the HI-HI group (203 ± 53 W to 219 ± 60 W); however, the increases in mitochondrial content was similar between groups, as reflected by similar increases in citrate synthase maximal activity, citrate synthase protein content and cytochrome c oxidase subunit IV protein content (p > .05 for interaction terms). This is the first study to show that a short-term “train low, compete high” intervention can improve whole-body exercise capacity. Further research is needed to determine whether this type of manipulation can also enhance performance in highly-trained subjects.

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Vitamin C Consumption Does Not Impair Training-Induced Improvements in Exercise Performance

International Journal of Sports Physiology and Performance ◽

10.1123/ijspp.6.1.58 ◽

2011 ◽

Vol 6 (1) ◽

pp. 58-69 ◽

Cited By ~ 30

Author(s):

Llion A. Roberts ◽

Kris Beattie ◽

Graeme L. Close ◽

James P. Morton

Keyword(s):

Vitamin C ◽

Exercise Performance ◽

High Intensity ◽

Time Trial ◽

Interval Training ◽

Running Economy ◽

Training Period ◽

High Intensity Interval Training ◽

Oxidation Rates ◽

High Intensity Interval

Purpose:To test the hypothesis that antioxidants can attenuate high-intensity interval training–induced improvements in exercise performance.Methods:Two groups of recreationally active males performed a high-intensity interval running protocol, four times per week for 4 wk. Group 1 (n = 8) consumed 1 g of vitamin C daily throughout the training period, whereas Group 2 (n = 7) consumed a visually identical placebo. Pre- and posttraining, subjects were assessed for VO2max, 10 km time trial, running economy at 12 km/h and distance run on the YoYo intermittent recovery tests level 1 and 2 (YoYoIRT1/2). Subjects also performed a 60 min run before and after training at a running velocity of 65% of pretraining VO2max so as to assess training-induced changes in substrate oxidation rates.Results:Training improved (P < .0005) VO2max, 10 km time trial, running economy, YoYoIRT1 and YoYoIRT2 in both groups, although there was no difference (P = .31, 0.29, 0.24, 0.76 and 0.59) between groups in the magnitude of training-induced improvements in any of the aforementioned parameters. Similarly, training also decreased (P < .0005) mean carbohydrate and increased mean fat oxidation rates during submaximal exercise in both groups, although no differences (P = .98 and 0.94) existed between training conditions.Conclusions:Daily oral consumption of 1 g of vitamin C during a 4 wk high-intensity interval training period does not impair training-induced improvements in the exercise performance of recreationally active males.

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Improvements in exercise performance with high-intensity interval training coincide with an increase in skeletal muscle mitochondrial content and function

Journal of Applied Physiology ◽

10.1152/japplphysiol.00445.2013 ◽

2013 ◽

Vol 115 (6) ◽

pp. 785-793 ◽

Cited By ~ 125

Author(s):

Robert Acton Jacobs ◽

Daniela Flück ◽

Thomas Christian Bonne ◽

Simon Bürgi ◽

Peter Møller Christensen ◽

...

Keyword(s):

Skeletal Muscle ◽

Exercise Capacity ◽

Exercise Performance ◽

High Intensity ◽

Interval Training ◽

Peripheral Fatigue ◽

High Intensity Interval Training ◽

Mitochondrial Content ◽

Respiratory Capacity ◽

High Intensity Interval

Six sessions of high-intensity interval training (HIT) are sufficient to improve exercise capacity. The mechanisms explaining such improvements are unclear. Accordingly, the aim of this study was to perform a comprehensive evaluation of physiologically relevant adaptations occurring after six sessions of HIT to determine the mechanisms explaining improvements in exercise performance. Sixteen untrained (43 ± 6 ml·kg−1·min−1) subjects completed six sessions of repeated ( 8 – 12 ) 60 s intervals of high-intensity cycling (100% peak power output elicited during incremental maximal exercise test) intermixed with 75 s of recovery cycling at a low intensity (30 W) over a 2-wk period. Potential training-induced alterations in skeletal muscle respiratory capacity, mitochondrial content, skeletal muscle oxygenation, cardiac capacity, blood volumes, and peripheral fatigue resistance were all assessed prior to and again following training. Maximal measures of oxygen uptake (V̇o2peak; ∼8%; P = 0.026) and cycling time to complete a set amount of work (∼5%; P = 0.008) improved. Skeletal muscle respiratory capacities increased, most likely as a result of an expansion of skeletal muscle mitochondria (∼20%, P = 0.026), as assessed by cytochrome c oxidase activity. Skeletal muscle deoxygenation also increased while maximal cardiac output, total hemoglobin, plasma volume, total blood volume, and relative measures of peripheral fatigue resistance were all unaltered with training. These results suggest that increases in mitochondrial content following six HIT sessions may facilitate improvements in respiratory capacity and oxygen extraction, and ultimately are responsible for the improvements in maximal whole body exercise capacity and endurance performance in previously untrained individuals.

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