The effect of pre-test carbohydrate ingestion on the anaerobic threshold, as determined by the lactate-minimum test.
The purpose of this study was to investigate the effect of pre-test carbohydrate (CHO) ingestion on anaerobic-threshold assessment using the lactate-minimum test (LMT). Fifteen competitive male distance runners capable of running 10 km in 33.5-43 min were used as subjects. LMT was performed following CHO (2x300 mL, 7% solution) or comparable placebo (Pl) ingestion, in a double-blind, randomized order. The LMT consisted of two high-intensity 1 min treadmill runs (17-21 km.h(-1)), followed by an 8 min recovery period. Subsequently, subjects performed 5 min running stages, incremented by 0.6 km.h(-1) and separated by 1 min blood-sampling intervals. Tests were terminated after 3 consecutive increases in blood-lactate concentration ([La]) had been observed. Finger-tip capillary blood was sampled for [La] and blood-glucose determination 30 min before the test's onset, during the recovery phase following the 2 high-intensity runs, and following each of the subsequent 5 min stages. Heart rate (HR) and rating of perceived exertion (RPE) were recorded after each stage. The lactate-minimum speed (LMS) was determined from the individual [La]-velocity plots and was considered reflective of the anaerobic threshold. Pre-test CHO ingestion had no effect on LMS (13.19+/-1.12 km.h(-1) vs. 13.17+/-1.08 km.h(-1) in CHO and Pl, respectively), nor on [La] and glucose concentration at that speed, or on HR and RPE responses. Pre-test CHO ingestion therefore does not affect LMS or the LMT-estimated anaerobic threshold.
Zinman College, at the Wingate Institute, Netanya, 42902, Israel.
Arie
A
Rotstein
Raffy
R
Dotan
Levana
L
Zigel
Tally
T
Greenberg
Yael
Y
Benyamini
Bareket
B
Falk
D000328:Adult; D015308:Anaerobic Threshold / Q000187:drug effects*; D000886:Anthropometry; D001786:Blood Glucose / Q000378:metabolism; D002241:Carbohydrates / Q000494:pharmacology*; D004311:Double-Blind Method; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects; D012420:Running / Q000502:physiology
D001786:Blood Glucose; D002241:Carbohydrates; D019344:Lactic Acid