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.
Adam B. Schroer, Michael J. Saunders, Daniel A. Baur, Christopher J. Womack and Nicholas D. Luden
Patricia W. Bauer, James M. Pivarnik, Deborah L. Feltz, Nigel Paneth and Christopher J. Womack
Physical activity (PA) is an important component of a healthy pregnancy and postpartum period. Since prospective PA monitoring throughout gestation is difficult, a valid PA recall tool would be of significant benefit to researchers. The purpose of this study was to evaluate the ability of women to recall their physical activity performed during pregnancy and postpartum, 6 years later.
Thirty women participated in an historical PA recall study. Pregnancy PA was monitored carefully via assisted physical activity diary (PAD) 6 years before the current investigation. A Modifiable Activity Questionnaire (MAQ) was used to assess current and past pregnancy PA. The MAQ was administered for each time period in the order of most distant past to most current. Leisure time energy expenditure values (kcal/kg/day) calculated from the PAD and the MAQ were compared.
MAQ energy expenditure values showed good positive relationships with PAD measures at 20 weeks gestation (r = .57; P < .01), 32 weeks gestation (r = .85; P < .01), and 12 weeks postpartum (r = .86; P < .01). Correlations found were similar to those from previous PA recall and MAQ validation studies using nonpregnant populations.
The MAQ is an appropriate tool to assess pregnancy and postpartum PA in women 6 years postpartum.