Skeletal muscle adaptation and performance responses to once a day versus twice every second day endurance training regimens

Exercise Metabolism Group, School of Medical Sciences, Bldg. 223.2.52, RMIT University, PO Box 71, Bundoora, Victoria 3083, Australia.
Journal of Applied Physiology (Impact Factor: 3.06). 09/2008; 105(5):1462-70. DOI: 10.1152/japplphysiol.90882.2008
Source: PubMed


We determined the effects of a cycle training program in which selected sessions were performed with low muscle glycogen content on training capacity and subsequent endurance performance, whole body substrate oxidation during submaximal exercise, and several mitochondrial enzymes and signaling proteins with putative roles in promoting training adaptation. Seven endurance-trained cyclists/triathletes trained daily (High) alternating between 100-min steady-state aerobic rides (AT) one day, followed by a high-intensity interval training session (HIT; 8 x 5 min at maximum self-selected effort) the next day. Another seven subjects trained twice every second day (Low), first undertaking AT, then 1-2 h later, the HIT. These training schedules were maintained for 3 wk. Forty-eight hours before and after the first and last training sessions, all subjects completed a 60-min steady-state ride (60SS) followed by a 60-min performance trial. Muscle biopsies were taken before and after 60SS, and rates of substrate oxidation were determined throughout this ride. Resting muscle glycogen concentration (412 +/- 51 vs. 577 +/- 34 micromol/g dry wt), rates of whole body fat oxidation during 60SS (1,261 +/- 247 vs. 1,698 +/- 174 min(-1)), the maximal activities of citrate synthase (45 +/- 2 vs. 54 +/- 1 dry wt(-1).min(-1)), and beta-hydroxyacyl-CoA-dehydrogenase (18 +/- 2 vs. 23 +/- 2 dry wt(-1).min(-1)) along with the total protein content of cytochrome c oxidase subunit IV were increased only in Low (all P < 0.05). Mitochondrial DNA content and peroxisome proliferator-activated receptor-gamma coactivator-1alpha protein levels were unchanged in both groups after training. Cycling performance improved by approximately 10% in both Low and High. We conclude that compared with training daily, training twice every second day compromised high-intensity training capacity. While selected markers of training adaptation were enhanced with twice a day training, the performance of a 1-h time trial undertaken after a 60-min steady-state ride was similar after once daily or twice every second day training programs.

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Available from: Louise Mary Burke, Oct 02, 2015
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    • "After 10 weeks of training time to exhaustion at 90% power output was increased in the twice-a-day leg only (294 vs. 113%, respectively). Similarly, trained men cycling twice every second day compared to once every day for 3 weeks, showed increased glycogen storage, fat oxidation and mitochondrial enzyme activity, although no improvement in performance was found (Yeo et al. 2008). Only a few studies have investigated the effect of CHO restriction during recovery. "
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    ABSTRACT: The aim was to determine if the metabolic adaptations, particularly PGC-1α and downstream metabolic genes were affected by restricting CHO following an endurance exercise bout in trained endurance athletes. A second aim was to compare baseline expression level of these genes to untrained. Elite endurance athletes (VO2max 66 ± 2 mL·kg(-1)·min(-1), n = 15) completed 4 h cycling at ~56% VO2max. During the first 4 h recovery subjects were provided with either CHO or only H2O and thereafter both groups received CHO. Muscle biopsies were collected before, after, and 4 and 24 h after exercise. Also, resting biopsies were collected from untrained subjects (n = 8). Exercise decreased glycogen by 67.7 ± 4.0% (from 699 ± 26.1 to 239 ± 29.5 mmol·kg(-1)·dw(-1)) with no difference between groups. Whereas 4 h of recovery with CHO partly replenished glycogen, the H2O group remained at post exercise level; nevertheless, the gene expression was not different between groups. Glycogen and most gene expression levels returned to baseline by 24 h in both CHO and H2O. Baseline mRNA expression of NRF-1, COX-IV, GLUT4 and PPAR-α gene targets were higher in trained compared to untrained. Additionally, the proportion of type I muscle fibers positively correlated with baseline mRNA for PGC-1α, TFAM, NRF-1, COX-IV, PPAR-α, and GLUT4 for both trained and untrained. CHO restriction during recovery from glycogen depleting exercise does not improve the mRNA response of markers of mitochondrial biogenesis. Further, baseline gene expression of key metabolic pathways is higher in trained than untrained. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.
    02/2015; 3(2). DOI:10.14814/phy2.12184
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    • "practical implications ( i . e . feeding strategies ) for those athletes who deliberately train in CHO - restricted states in order to enhance skeletal muscle adaptations to endurance training . Despite the apparent advantage to carefully scheduling periods of fasted ( Van Proeyen et al . 2011 ) and / or glyco - gen - depleted endurance training ( Yeo et al . 2008 ; Morton et al . 2009 ) , such approaches may be limited in that skel - etal muscle protein oxidation and breakdown are increased ( Lemon and Mullin 1980 ; Howarth et al . 2010 ) , and hence net protein balance becomes negative if amino acids are also not ingested ( Hulston et al . 2011 ) . If performed chron - ically ( especially in th"
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    ABSTRACT: Given that the enhanced oxidative adaptations observed when training in carbohydrate (CHO)-restricted states is potentially regulated through free fatty acid (FFA)-mediated signalling and that leucine-rich protein elevates muscle protein synthesis, the present study aimed to test the hypothesis that leucine-enriched protein feeding enhances circulating leucine concentration but does not impair FFA availability or whole body lipid oxidation during exercise. Nine males cycled for 2 h at 70 % VO2peak when fasted (PLACEBO) or having consumed a whey protein solution (WHEY) or a leucine-enriched whey protein gel (GEL), administered as 22 g 1 h pre-exercise, 11 g/h during and 22 g 30 min post-exercise. Total leucine administration was 14.4 g and 6.3 in GEL and WHEY, respectively. Mean plasma leucine concentrations were elevated in GEL (P = 0.001) compared with WHEY and PLACEBO (375 ± 100, 272 ± 51, 146 ± 14 µmol L(-1), respectively). No differences (P = 0.153) in plasma FFA (WHEY 0.53 ± 0.30, GEL 0.45 ± 0.25, PLACEBO 0.65 ± 0.30, mmol L(-1)) or whole body lipid oxidation during exercise (WHEY 0.37 ± 0.26, GEL 0.36 ± 0.24, PLACEBO 0.34 ± 0.24 g/min) were apparent between trials, despite elevated (P = 0.001) insulin in WHEY and GEL compared with PLACEBO (38 ± 16, 35 ± 16, 22 ± 11 pmol L(-1), respectively). We conclude that leucine-enriched protein feeding does not impair FFA availability or whole body lipid oxidation during exercise, thus having practical applications for athletes who deliberately train in CHO-restricted states to promote skeletal muscle adaptations.
    Amino Acids 12/2014; 47(2). DOI:10.1007/s00726-014-1876-y · 3.29 Impact Factor
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    • ") diets designed to achieve energy balance (Yeo, Carey, Burke, Spriet, & Hawley, 2011), although decrements in high-intensity sprint performance have been demonstrated (Havemann et al., 2006). Importantly, the responses of athletes to low-carbohydrate intakes appear to be highly variable and can impair training capacity in some athletes (Yeo et al., 2008). Thus, it appears reasonable to suggest that the decision to reduce carbohydrate and/or fat intake to facilitate increased protein consumption should be made on a case-by-case basis with consideration of the athlete's 4 C. H. Murphy et al. sport-specific training needs and personal tolerance, along with the amount of time available to achieve weight loss. "
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    ABSTRACT: Abstract A large body of evidence now shows that higher protein intakes (2-3 times the protein Recommended Dietary Allowance (RDA) of 0.8 g/kg/d) during periods of energy restriction can enhance fat-free mass (FFM) preservation, particularly when combined with exercise. The mechanisms underpinning the FFM-sparing effect of higher protein diets remain to be fully elucidated but may relate to the maintenance of the anabolic sensitivity of skeletal muscle to protein ingestion. From a practical point of view, athletes aiming to reduce fat mass and preserve FFM should be advised to consume protein intakes in the range of ∼1.8-2.7 g kg(-1) d(-1) (or ∼2.3-3.1 g kg(-1) FFM) in combination with a moderate energy deficit (-500 kcal) and the performance of some form of resistance exercise. The target level of protein intake within this recommended range requires consideration of a number of case-specific factors including the athlete's body composition, habitual protein intake and broader nutrition goals. Athletes should focus on consuming high-quality protein sources, aiming to consume protein feedings evenly spaced throughout the day. Post-exercise consumption of 0.25-0.3 g protein meal(-1) from protein sources with high leucine content and rapid digestion kinetics (i.e. whey protein) is recommended to optimise exercise-induced muscle protein synthesis. When protein is consumed as part of a mixed macronutrient meal and/or before bed slightly higher protein doses may be optimal.
    European Journal of Sport Science 07/2014; 15(1):1-8. DOI:10.1080/17461391.2014.936325 · 1.55 Impact Factor
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