Manipulating Carbohydrate Availability Between Twice-Daily Sessions of High-Intensity Interval Training Over 2 Weeks Improves Time-Trial Performance

2015 ◽  
Vol 25 (5) ◽  
pp. 463-470 ◽  
Author(s):  
Andrew J.R. Cochran ◽  
Frank Myslik ◽  
Martin J. MacInnis ◽  
Michael E. Percival ◽  
David Bishop ◽  
...  
Keyword(s):  
Exercise Performance ◽  
High Intensity ◽  
Citrate Synthase ◽  
Time Trial ◽  
Interval Training ◽  
High Intensity Interval Training ◽  
Mitochondrial Content ◽  
Trained Subjects ◽  
High Intensity Interval ◽  
Trial 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.

scholarly journals Roller-Ski Aerobic High-Intensity Interval Training Improves the VO2max and Anaerobic Power in Cross-Country Skiers

2017 ◽  
Vol 6 (2) ◽  
pp. 27-33
Author(s):  
BAHAR ATEŞ ◽  
Ebru ÇETİN
Keyword(s):  
High Intensity ◽  
Anaerobic Power ◽  
Time Trial ◽  
Interval Training ◽  
High Intensity Interval Training ◽  
Time Trial Performance ◽  
Post Test ◽  
Cross Country ◽  
High Intensity Interval ◽  
Trial Performance

The purpose of this study was to investigate the 8-week of roller-ski aerobic high-intensity interval training on aerobic and anaerobic power in cross-country skiers. 10 male [age, 18,28±2,1 years; height, 171,26±4,12 cm; weight, 61,39±6,28 kg] and 8 female [age, 16,05±0.3 years; height, 158,3±6,47 cm; weight, 49,34±0.7 kg]  junior cross-country skiers completed the study. All skiers performed 2x2-km all-out uphill intervals with roller-skis, 3 times a week, in addition to their traditional training program. Measurements included VO2max, anaerobic power, and also for 2-km time-trial performance. All values were listed as pre-to post-test mean [±SD], significant level, and percentage changes [%]. Pre-to post-testing changes in VO2max, anaerobic power, and also 2-km time-trial performance were significantly higher during all post-test trials in all groups [p<0.005]. As a result, we suggest that the skiers should integrate the roller-ski aerobic high-intensity interval uphill models in their training programs for improving performance.

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

2011 ◽  
Vol 6 (1) ◽  
pp. 58-69 ◽  
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.

scholarly journals A flow resistive inspiratory muscle training mask worn during high-intensity interval training does not improve 5 km running time-trial performance

2020 ◽  
Author(s):  
Mark A. Faghy ◽  
Peter I. Brown ◽  
Nicola M. Davis ◽  
J. P. Mayes ◽  
Tom M. Maden-Wilkinson
Keyword(s):  
High Intensity ◽  
Time Trial ◽  
Interval Training ◽  
Inspiratory Muscle ◽  
Inspiratory Muscle Training ◽  
High Intensity Interval Training ◽  
Muscle Training ◽  
Time Trial Performance ◽  
High Intensity Interval ◽  
Trial Performance

Abstract Purpose There is little evidence of the ergogenic effect of flow-resistive masks worn during exercise. We compared a flow-resistive face mask (MASK) worn during high-intensity interval training (HIIT) against pressure threshold loading inspiratory muscle training (IMT). Methods 23 participants (13 males) completed a 5 km time trial and six weeks of HIIT (3 sessions weekly). HIIT (n = 8) consisted of repeated work (2 min) at the speed equivalent to 95% $${\dot{\text{V}}}$$ V ˙ O2 peak with equal rest. Repetitions were incremental (six in weeks 1, 2 and 6, eight in weeks 3 and 4 and ten in week 5). Participants were allocated to one of three training groups. MASK (n = 8) wore a flow-resistive mask during all sessions. The IMT group (n = 8) completed 2 × 30 breaths daily at 50% maximum inspiratory pressure (PImax). A control group (CON, n = 7) completed HIIT only. Following HIIT, participants completed two 5 km time trials, the first matched identically to pre-intervention trial (ISO time), and a self-paced effort. Results Time trial performance was improved in all groups (MASK 3.1 ± 1.7%, IMT, 5.7 ± 1.5% and CON 2.6 ± 1.0%, p < 0.05). IMT improved greater than MASK and CON (p = 0.004). Post intervention, PImax and diaphragm thickness were improved in IMT only (32% and 9.5%, respectively, p = 0.003 and 0.024). Conclusion A flow-resistive mask worn during HIIT provides no benefit to 5 km performance when compared to HIIT only. Supplementing HIIT with IMT improves respiratory muscle strength, morphology and performance greater than HIIT alone.

Creatine Monohydrate Supplementation Does Not Augment Fitness, Performance, or Body Composition Adaptations in Response to Four Weeks of High-Intensity Interval Training in Young Females

2017 ◽  
Vol 27 (3) ◽  
pp. 285-292 ◽  
Author(s):  
Scott C. Forbes ◽  
Nathan Sletten ◽  
Cody Durrer ◽  
Étienne Myette-Côté ◽  
D. Candow ◽  
...  
Keyword(s):  
Body Composition ◽  
Insulin Sensitivity ◽  
Cardiorespiratory Fitness ◽  
High Intensity ◽  
Time Trial ◽  
Interval Training ◽  
High Intensity Interval Training ◽  
Time Trial Performance ◽  
High Intensity Interval ◽  
Trial Performance

High-intensity interval training (HIIT) has been shown to improve cardiorespiratory fitness, performance, body composition, and insulin sensitivity. Creatine (Cr) supplementation may augment responses to HIIT, leading to even greater physiological adaptations. The purpose of this study was to determine the effects of 4 weeks of HIIT (three sessions/week) combined with Cr supplementation in recreationally active females. Seventeen females (age = 23 ± 4 yrs; BMI = 23.4 ± 2.4) were randomly assigned to either Cr (Cr; 0.3 g・kg-1・d-1 for 5 d followed by 0.1 g・kg-1・d-1 for 23 days; n = 9) or placebo (PLA; n = 8). Before and after the intervention, VO2peak, ventilatory threshold (VT), time-trial performance, lean body mass and fat mass, and insulin sensitivity were assessed. HIIT improved VO2peak (Cr = +10.2%; PLA = +8.8%), VT (Cr = +12.7%; PLA = +9.9%), and time-trial performance (Cr = -11.5%; PLA = -11.6%) with no differences between groups (time main effects, all p < .001). There were no changes over time for fat mass (Cr = -0.3%; PLA = +4.3%), whole-body lean mass (Cr = +0.5%; PLA = -0.9%), or insulin resistance (Cr = +3.9%; PLA = +18.7%). In conclusion, HIIT is an effective way to improve cardiorespiratory fitness, VT, and time-trial performance. The addition of Cr to HIIT did not augment improvements in cardiorespiratory fitness, performance or body composition in recreationally active females.

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

2013 ◽  
Vol 115 (6) ◽  
pp. 785-793 ◽  
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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