| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1Human Performance Laboratory, School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, B15 2TT Birmingham, United Kingdom; 2School of Human Movement Studies, Queensland University of Technology, Brisbane, QLD 4001 Queensland, Australia; 3Optimal Performance, Clifton, BS8 4EJ Bristol, United Kingdom; 4QinetiQ, Centre for Human Sciences, GU14 OLK Farnborough, United Kingdom
Submitted 9 September 2003 ; accepted in final form 26 November 2003
The aim of this study was to determine whether consumption of a diet containing 8.5 g carbohydrate (CHO)·kg-1·day-1 (high CHO; HCHO) compared with 5.4 g CHO·kg-1·day-1 (control; Con) during a period of intensified training (IT) would result in better maintenance of physical performance and mood state. In a randomized cross-over design, seven trained runners [maximal O2 uptake (
O2 max) 64.7 ± 2.6 ml·kg-1·min-1] performed two 11-day trials consuming either the Con or the HCHO diet. The last week of both trials consisted of IT. Performance was measured with a preloaded 8-km all-out run on the treadmill and 16-km all-out runs outdoors. Substrate utilization was measured using indirect calorimetry and continuous [U-13C]glucose infusion during 30 min of running at 58 and 77% O2 max. Time to complete 8 km was negatively affected by the IT: time significantly increased by 61 ± 23 and 155 ± 38 s in the HCHO and Con trials, respectively. The 16-km times were significantly increased (by 8.2 ± 2.1%) during the Con trial only. The Daily Analysis of Life Demands of Athletes questionnaire showed significant deterioration in mood states in both trials, whereas deterioration in global mood scores, as assessed with the Profile of Mood States, was more pronounced in the Con trial. Scores for fatigue were significantly higher in the Con compared with the HCHO trial. CHO oxidation decreased significantly from 1.7 ± 0.2 to 1.2 ± 0.2 g/min over the course of the Con trial, which was completely accounted for by a decrease in muscle glycogen oxidation. These findings indicate that an increase in dietary CHO content from 5.4 to 8.5 g CHO·kg-1·day-1 (41 vs. 65% total energy intake, respectively) allowed better maintenance of physical performance and mood state over the course of training, thereby reducing the symptoms of overreaching.
overtraining; [U-13C]glucose; muscle glycogen
This article has been cited by other articles:
|
|
 |
|
  W. K. Yeo, C. D. Paton, A. P. Garnham, L. M. Burke, A. L. Carey, and J. A. Hawley Skeletal muscle adaptation and performance responses to once a day versus twice every second day endurance training regimens J Appl Physiol, November 1, 2008; 105(5): 1462 - 1470. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L Bosquet, S Merkari, D Arvisais, and A E Aubert Is heart rate a convenient tool to monitor over-reaching? A systematic review of the literature Br. J. Sports Med., September 1, 2008; 42(9): 709 - 714. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. De Bock, W. Derave, B. O. Eijnde, M. K. Hesselink, E. Koninckx, A. J. Rose, P. Schrauwen, A. Bonen, E. A. Richter, and P. Hespel Effect of training in the fasted state on metabolic responses during exercise with carbohydrate intake J Appl Physiol, April 1, 2008; 104(4): 1045 - 1055. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. L. Halson, G. I. Lancaster, J. Achten, M. Gleeson, and A. E. Jeukendrup Effects of carbohydrate supplementation on performance and carbohydrate oxidation after intensified cycling training J Appl Physiol, October 1, 2004; 97(4): 1245 - 1253. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
