PMID- 24937205
OWN - NLM
STAT- MEDLINE
DCOM- 20150602
LR  - 20151119
IS  - 1543-2742 (Electronic)
IS  - 1526-484X (Linking)
VI  - 24
IP  - 5
DP  - 2014 Oct
TI  - Cycling time trial performance may be impaired by whey protein and L-alanine 
      intake during prolonged exercise.
PG  - 507-15
LID - 10.1123/ijsnem.2013-0173 [doi]
AB  - Previous studies reported that adding protein (PRO) to carbohydrate (CHO) 
      solutions enhances endurance performance. The ergogenic effect may be a function 
      of additional protein/amino acid calories, but this has not been examined. In 
      addition, although supplemental L-alanine (ALA) is readily oxidized during 
      exercise, the subsequent impact on metabolism and prolonged endurance performance 
      is unknown. The purpose of this investigation was to independently gauge the 
      impact of whey PRO hydrolysate and ALA supplementation on performance and various 
      physiological parameters. Eight cyclists (age: 22.3 +/- 5.6 yr, weight: 70.0 +/- 8.0 
      kg, VO2max: 59.4 +/- 4.9 ml . kg(-1) . min(-1)) performed 120 min of constant-load 
      cycling (55% of peak power) followed by a 30-km time trial (TT) under placebo 
      (PLA), PRO, and ALA conditions. Magnitude-based qualitative inferences were 
      applied to evaluate treatment differences and data are presented as percent 
      difference between treatments +/- 90% confidence limit. Both ALA (2.1 +/- 2.7%) and 
      PRO intake (-2.1 +/- 2.2%) possibly harmed performance compared with PLA. Of 
      interest, heart rate was possibly lower with ALA than PLA at 20- (-2.7 +/- 3.4%) 
      and 120-min (-1.7 +/- 2.9%) of constant-load cycling and the serum interleukin-6 
      (IL-6) response to 120 min of cycling was likely attenuated with PRO compared 
      with PLA (PLA, 6.6 +/- 3.7 fold vs. PRO, 2.9 +/- 1.8 fold). In addition, blood 
      glucose levels were lower with PRO than PLA at 20- (-8.8 +/- 2.3%; very likely) and 
      120-min (-4.9 +/- 4.6%; likely) of constant-load cycling. Although ALA intake 
      appears to lower HR and PRO ingestion dampens the IL-6 response to exercise, the 
      ingestion of PRO (without CHO) or ALA does not enhance, and may actually impair, 
      performance following prolonged cycling.
FAU - Schroer, Adam B
AU  - Schroer AB
AD  - Dept. of Kinesiology, James Madison University, Harrisonburg, VA.
FAU - Saunders, Michael J
AU  - Saunders MJ
FAU - Baur, Daniel A
AU  - Baur DA
FAU - Womack, Christopher J
AU  - Womack CJ
FAU - Luden, Nicholas D
AU  - Luden ND
LA  - eng
PT  - Journal Article
PT  - Randomized Controlled Trial
PT  - Research Support, Non-U.S. Gov't
DEP - 20140617
PL  - United States
TA  - Int J Sport Nutr Exerc Metab
JT  - International journal of sport nutrition and exercise metabolism
JID - 100939812
RN  - 0 (Blood Glucose)
RN  - 0 (Interleukin-6)
RN  - 0 (Milk Proteins)
RN  - 0 (Whey Proteins)
RN  - 33X04XA5AT (Lactic Acid)
RN  - OF5P57N2ZX (Alanine)
SB  - IM
MH  - Adolescent
MH  - Adult
MH  - Alanine/*pharmacology
MH  - Bicycling
MH  - Blood Glucose/metabolism
MH  - Dietary Supplements
MH  - Energy Intake
MH  - Exercise/*physiology
MH  - Exercise Test
MH  - Female
MH  - Heart Rate/drug effects
MH  - Humans
MH  - Interleukin-6/blood
MH  - Lactic Acid/blood
MH  - Male
MH  - Milk Proteins/*pharmacology
MH  - Oxygen Consumption
MH  - Physical Endurance/*drug effects/physiology
MH  - Physical Exertion/*drug effects/physiology
MH  - Whey Proteins
MH  - Young Adult
EDAT- 2014/06/18 06:00
MHDA- 2015/06/03 06:00
CRDT- 2014/06/18 06:00
PHST- 2014/06/18 06:00 [entrez]
PHST- 2014/06/18 06:00 [pubmed]
PHST- 2015/06/03 06:00 [medline]
AID - 2013-0173 [pii]
AID - 10.1123/ijsnem.2013-0173 [doi]
PST - ppublish
SO  - Int J Sport Nutr Exerc Metab. 2014 Oct;24(5):507-15. doi: 
      10.1123/ijsnem.2013-0173. Epub 2014 Jun 17.