In:
International Journal of Sports Physiology and Performance, Human Kinetics, Vol. 14, No. 9 ( 2019-10-1), p. 1233-1243
Kurzfassung:
Purpose : To assess energy and carbohydrate (CHO) availability and changes in blood hormones in 6 professional male cyclists over multiple single-day races. Methods : The authors collected weighed-food records, power-meter data, and morning body mass measurements across 8 d. CHO intakes were compared with contemporary guidelines. Energy availability (EA) was calculated as energy intake minus exercise energy expenditure, relative to fat-free mass (FFM). Skinfold thickness and blood metabolic and reproductive hormones were measured prestudy and poststudy. Statistical significance was defined as P ≤ .05. Results : Body mass ( P = .11) or skinfold thickness ( P = .75) did not change across time, despite alternate-day low EA (14 [9] vs 57 [10] kcal·kg −1 FFM·d −1 , race vs rest days, respectively; P 〈 .001). Cyclists with extremely low EA on race days ( 〈 10 kcal·kg −1 FFM·d −1 ; n = 2) experienced a trend toward decreased testosterone (−14%) and insulin-like growth factor 1 (−25%), despite being high EA ( 〉 46 kcal·kg −1 FFM·d −1 ) on days between. CHO intakes were significantly higher on race versus rest days (10.7 [1.3] vs 6.4 [0.8] g·kg −1 ·d −1 , respectively; P 〈 .001). The cyclists reached contemporary prerace fueling targets (3.4 [0.7] g·kg −1 ·3 h −1 CHO; P = .24), while the execution of CHO guidelines during race (51 [9] g·h −1 ; P = .048) and within acute (1.6 [0.5] g·kg −1 ·3 h −1 ; P = .002) and prolonged (7.4 [1.0] g·kg −1 ·24 h −1 ; P = .002) postrace recovery was poor. Conclusions : The authors are the first to report the day-by-day periodization of energy and CHO in a small sample of professional cyclists. They also examined the logistics of conducting a field study under stressful conditions in which major cooperation from the subjects and team management is needed. Their commentary around these challenges and possible solutions is a major novelty of the article.
Materialart:
Online-Ressource
ISSN:
1555-0265
,
1555-0273
DOI:
10.1123/ijspp.2018-0842
Sprache:
Unbekannt
Verlag:
Human Kinetics
Publikationsdatum:
2019
SSG:
31
