Patrick B. Wilson, Gregory S. Rhodes and Stacy J. Ingraham
Self-report (SR) has been the primary method used to assess fluid intake during endurance events, but unfortunately, little is known about the validity of SR. The purpose of this study was to compare SR fluid intake with direct measurement (DM) during a 70.3-mile triathlon.
Fifty-three (42 men, 11 women) individuals competing in a 70.3-mile triathlon participated in the study. On the 13.1-mile-run section of the triathlon, 11 research stations provided fluid in bottles filled with 163 mL of water or carbohydrate-electrolyte beverage (CEB). Participants submitted bottles 25 m past aid stations to be reweighed postrace. Participants also answered questions regarding fluid intake postrace. Bland-Altman plots and 95% limits of agreement were used to assess precision of the measures, while least-squares regression assessed linear agreement.
SR intakes during the run ranged from 0–1793, 0–1837, and 0–2628 mL for water, CEB, and total fluid, with corresponding DM intakes of 0–1599, 0–1642, and 0–2250 mL. DM and SR showed strong linear agreement for water, CEB, and total fluid (R
2 = .71, .80, and .80). Mean differences between the measures on the Bland-Altman plots were small (13–41 mL), but relatively large differences (±500 mL) between the measures were apparent for some participants.
SR is the predominant methodology used in field studies assessing hydration, despite little to no data confirming its validity. The results herein suggest that fluid-intake-assessment methodology should be chosen on a case-by-case basis and that caution should be used when interpreting data based on SR.
Patrick B. Wilson, Stacy J. Ingraham, Chris Lundstrom and Gregory Rhodes
The effects of dietary factors such as carbohydrate (CHO) on endurance-running performance have been extensively studied under laboratory-based and simulated field conditions. Evidence from “reallife” events, however, is poorly characterized. The purpose of this observational study was to examine the associations between prerace and in-race nutrition tendencies and performance in a sample of novice marathoners.
Forty-six college students (36 women and 10 men) age 21.3 ± 3.3 yr recorded diet for 3 d before, the morning of, and during a 26.2-mile marathon. Anthropometric, physiological, and performance measurements were assessed before the marathon so the associations between diet and marathon time could be included as part of a stepwise-regression model.
Mean marathon time was 266 ± 42 min. A premarathon 2-mile time trial explained 73% of the variability in marathon time (adjusted R
2 = .73, p < .001). Day-before + morning-of CHO (DBMC) was the only other significant predictor of marathon time, explaining an additional 4% of the variability in marathon time (adjusted R
2 = .77, p = .006). Other factors such as age, body-mass index, gender, day-before + morning-of energy, and in-race CHO were not significant independent predictors of marathon time.
In this sample of primarily novice marathoners, DBMC intake was associated with faster marathon time, independent of other known predictors. These results suggest that novice and recreational marathoners should consider consuming a moderate to high amount of CHO in the 24–36 hr before a marathon.
Patrick B. Wilson, John S. Fitzgerald, Gregory S. Rhodes, Chris J. Lundstrom and Stacy J. Ingraham
Analgesics are commonly used by individuals undertaking endurance training; unfortunately, many commonly-used analgesics cause significant adverse effects. Ginger root (Zingiber officinale) has been used effectively as an analgesic in several contexts, but to date, no research is available to evaluate ginger root’s effects in the context of endurance training.
Determine whether ginger root supplementation reduces muscle soreness and prevents impairments in muscle function following a long-distance training run.
Randomized, double-blind, placebo-controlled trial.
University marathon training course.
Twenty college students (n = 8 for ginger root group and n = 12 for placebo group).
Supplementation with 2.2 g·day–1 of ginger root or placebo for three days before, the day of, and the day after a 20–22 mile training run.
Main Outcome Measures:
Four days before and 24-hr postrun, participants rated soreness on a 100-mm visual analog scale, while vertical jump (VJ), peak force, and average rate of force development (RFD) were assessed during a squat jump. Quade’s rank analysis of covariance was used to assess between-group differences.
Median (range) soreness during jogging at 24-hr postrun was lower with ginger root supplementation (37 mm, 15–58) compared with placebo (62 mm, 6–85) (F = 4.6, p = .04). No significant differences for VJ, peak force, and RFD were found between groups.
Ginger root may modestly reduce muscle soreness stemming from long-distance running, although it may have little to no effect on measures of muscle function during a VJ. Future studies should explore the mechanisms responsible for reductions in running-induced muscle soreness, as well as evaluate the benefit-to-risk profile of ginger root in the context of endurance training.