PMID- 28723843
OWN - NLM
STAT- MEDLINE
DCOM- 20180305
LR  - 20180305
IS  - 1530-0315 (Electronic)
IS  - 0195-9131 (Linking)
VI  - 49
IP  - 12
DP  - 2017 Dec
TI  - No Superior Adaptations to Carbohydrate Periodization in Elite Endurance 
      Athletes.
PG  - 2486-2497
LID - 10.1249/MSS.0000000000001377 [doi]
AB  - PURPOSE: The present study investigated the effects of periodic carbohydrate 
      (CHO) restriction on endurance performance and metabolic markers in elite 
      endurance athletes. METHODS: Twenty-six male elite endurance athletes (maximal 
      oxygen consumption (V O2max), 65.0 mL O2.kg.min) completed 4 wk of regular 
      endurance training while being matched and randomized into two groups training 
      with (low) or without (high) CHO manipulation 3 d.wk. The CHO manipulation days 
      consisted of a 1-h high-intensity bike session in the morning, recovery for 7 h 
      while consuming isocaloric diets containing either high CHO (414 +/- 2.4 g) or low 
      CHO (79.5 +/- 1.0 g), and a 2-h moderate bike session in the afternoon with or 
      without CHO. V O2max, maximal fat oxidation, and power output during a 30-min 
      time trial (TT) were determined before and after the training period. The TT was 
      undertaken after 90 min of intermittent exercise with CHO provision before the 
      training period and both CHO and placebo after the training period. Muscle 
      biopsies were analyzed for glycogen, citrate synthase (CS) and 
      beta-hydroxyacyl-coenzyme A dehydrogenase (HAD) activity, carnitine 
      palmitoyltransferase (CPT1b), and phosphorylated acetyl-CoA carboxylase (pACC). 
      RESULTS: The training effects were similar in both groups for all parameters. On 
      average, V O2max and power output during the 30-min TT increased by 5% +/- 1% (P < 
      0.05) and TT performance was similar after CHO and placebo during the preload 
      phase. Training promoted overall increases in glycogen content (18% +/- 5%), CS 
      activity (11% +/- 5%), and pACC (38% +/- 19%; P < 0.05) with no differences between 
      groups. HAD activity and CPT1b protein content remained unchanged. CONCLUSIONS: 
      Superimposing periodic CHO restriction to 4 wk of regular endurance training had 
      no superior effects on performance and muscle adaptations in elite endurance 
      athletes.
FAU - Gejl, Kasper Degn
AU  - Gejl KD
AD  - 1Department of Sports Science and Clinical Biomechanics, University of Southern 
      Denmark, Odense, DENMARK; 2Section for Sport Science, Department of Public 
      Health, Aarhus University, Aarhus, DENMARK; 3SMI, Department of Health Science 
      and Technology, Faculty of Medicine, Aalborg University, Aalborg, DENMARK; 
      4Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, DENMARK; 
      5Department of Infectious Diseases, Center for Physical Activity Research, 
      Rigshospitalet, University of Copenhagen, Copenhagen, DENMARK; 6Department of 
      Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, DENMARK; 
      7Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, 
      SWEDEN; 8Swedish School of Sport and Health Sciences, Stockholm, SWEDEN; 9Elite 
      Performance Centre, Swedish Sports Confederation, Stockholm, SWEDEN; 10Swedish 
      Winter Sports Research Centre, Department of Health Sciences, Mid Sweden 
      University, Ostersund, SWEDEN; and 11Swedish Olympic Committee, Stockholm, 
      SWEDEN.
FAU - Thams, Line Bork
AU  - Thams LB
FAU - Hansen, Mette
AU  - Hansen M
FAU - Rokkedal-Lausch, Torben
AU  - Rokkedal-Lausch T
FAU - Plomgaard, Peter
AU  - Plomgaard P
FAU - Nybo, Lars
AU  - Nybo L
FAU - Larsen, Filip J
AU  - Larsen FJ
FAU - Cardinale, Daniele A
AU  - Cardinale DA
FAU - Jensen, Kurt
AU  - Jensen K
FAU - Holmberg, Hans-Christer
AU  - Holmberg HC
FAU - Vissing, Kristian
AU  - Vissing K
FAU - Ortenblad, Niels
AU  - Ortenblad N
LA  - eng
PT  - Journal Article
PT  - Randomized Controlled Trial
PL  - United States
TA  - Med Sci Sports Exerc
JT  - Medicine and science in sports and exercise
JID - 8005433
RN  - 0 (Dietary Carbohydrates)
RN  - 0 (Fatty Acids, Essential)
RN  - 9005-79-2 (Glycogen)
SB  - IM
MH  - Adaptation, Physiological
MH  - Body Composition
MH  - Diet
MH  - Dietary Carbohydrates/*administration & dosage
MH  - Energy Metabolism/physiology
MH  - Fatty Acids, Essential/metabolism
MH  - Glycogen/metabolism
MH  - Humans
MH  - Male
MH  - Mitochondria, Muscle/metabolism
MH  - Muscle, Skeletal/enzymology/*metabolism
MH  - Oxygen Consumption/physiology
MH  - Physical Conditioning, Human/*methods
MH  - Physical Endurance/*physiology
MH  - Sports/*physiology
EDAT- 2017/07/21 06:00
MHDA- 2018/03/06 06:00
CRDT- 2017/07/21 06:00
PHST- 2017/07/21 06:00 [pubmed]
PHST- 2018/03/06 06:00 [medline]
PHST- 2017/07/21 06:00 [entrez]
AID - 10.1249/MSS.0000000000001377 [doi]
PST - ppublish
SO  - Med Sci Sports Exerc. 2017 Dec;49(12):2486-2497. doi: 
      10.1249/MSS.0000000000001377.