TY - JOUR
T1 - Special Environments
T2 - Altitude and Heat
AU - Saunders, Philo U
AU - Garvican-Lewis, Laura A
AU - Chapman, Robert F
AU - Périard, Julien D
N1 - Publisher Copyright:
© 2019 Human Kinetics, Inc.
PY - 2019/3
Y1 - 2019/3
N2 - 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 six days over 2 wk, subjects completed two training sessions, each consisting of 5 x 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-h period between sessions. The training-induced improvement in 250-kJ time trial performance was greater (p = 0.02) in the HI-LO group (211 ± 66 W to 244 ± 75 W) compared to 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 > 0.05 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.
AB - 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 six days over 2 wk, subjects completed two training sessions, each consisting of 5 x 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-h period between sessions. The training-induced improvement in 250-kJ time trial performance was greater (p = 0.02) in the HI-LO group (211 ± 66 W to 244 ± 75 W) compared to 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 > 0.05 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.
KW - Acclimatization
KW - Athletes
KW - Performance
KW - Training
UR - http://www.scopus.com/inward/record.url?scp=85064968541&partnerID=8YFLogxK
U2 - 10.1123/ijsnem.2018-0256
DO - 10.1123/ijsnem.2018-0256
M3 - Article
C2 - 30676138
SN - 1526-484X
VL - 29
SP - 210
EP - 219
JO - International Journal of Sport Nutrition and Exercise Metabolism
JF - International Journal of Sport Nutrition and Exercise Metabolism
IS - 2
ER -