PMID- 30860404
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20231026
IS  - 1555-0273 (Electronic)
IS  - 1555-0265 (Linking)
VI  - 14
IP  - 9
DP  - 2019 Oct 1
TI  - Alternate-Day Low Energy Availability During Spring Classics in Professional 
      Cyclists.
PG  - 1233-1243
LID - 10.1123/ijspp.2018-0842 [doi]
AB  - 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.
FAU - Heikura, Ida A
AU  - Heikura IA
FAU - Quod, Marc
AU  - Quod M
FAU - Strobel, Nicki
AU  - Strobel N
FAU - Palfreeman, Roger
AU  - Palfreeman R
FAU - Civil, Rita
AU  - Civil R
FAU - Burke, Louise M
AU  - Burke LM
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Int J Sports Physiol Perform
JT  - International journal of sports physiology and performance
JID - 101276430
SB  - IM
OTO - NOTNLM
OT  - hormones
OT  - nutrition periodization
OT  - professional cycling
OT  - single-day racing
EDAT- 2019/03/13 06:00
MHDA- 2019/03/13 06:01
CRDT- 2019/03/13 06:00
PHST- 2018/11/01 00:00 [received]
PHST- 2019/02/11 00:00 [revised]
PHST- 2019/02/14 00:00 [accepted]
PHST- 2019/03/13 06:01 [medline]
PHST- 2019/03/13 06:00 [pubmed]
PHST- 2019/03/13 06:00 [entrez]
AID - ijspp.2018-0842 [pii]
AID - 10.1123/ijspp.2018-0842 [doi]
PST - ppublish
SO  - Int J Sports Physiol Perform. 2019 Oct 1;14(9):1233-1243. doi: 
      10.1123/ijspp.2018-0842.