Low vs. high glycemic index carbohydrate gel ingestion during simulated 64-km cycling time trial performance

Conrad P Earnest, S L Lancaster, C J Rasmussen, C M Kerksick, A Lucia, M C Greenwood, A L Almada, P A Cowan, R B Kreider

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

We examined the effect of low and high glycemic index (GI) carbohydrate (CHO) feedings during a simulated 64-km cycling time trial (TT) in nine subjects ([mean +/- SEM], age = 30 +/- 1 years; weight = 77.0 +/- 2.6 kg). Each rider completed three randomized, double blind, counter-balanced, crossover rides, where riders ingested 15 g of low GI (honey; GI = 35) and high GI (dextrose; GI = 100) CHO every 16 km. Our results showed no differences between groups for the time to complete the entire TT (honey = 128 minutes, 42 seconds +/- 3.6 minutes; dextrose = 128 minutes, 18 seconds +/- 3.8 minutes; placebo = 131 minutes, 18 seconds +/- 3.9 minutes). However, an analysis of total time alone may not portray an accurate picture of TT performance under CHO-supplemented conditions. For example, when the CHO data were collapsed, the CHO condition (128 minutes, 30 seconds) proved faster than placebo condition (131 minutes, 18 seconds; p < 0.02). Furthermore, examining the percent differences and 95% confidence intervals (CI) shows the two CHO conditions to be generally faster, as the majority of the CI lies in the positive range: placebo vs. dextrose (2.36% [95% CI; -0.69, 4.64]) and honey (1.98% [95% CI; -0.30, 5.02]). Dextrose vs. honey was 0.39% (95% CI; -3.39, 4.15). Within treatment analysis also showed that subjects generated more watts (W) over the last 16 km vs. preceding segments for dextrose (p < 0.002) and honey (p < 0.0004) treatments. When the final 16-km W was expressed as a percentage of pretest maximal W, the dextrose treatment was greater than placebo (p < 0.05). A strong trend was noted for the honey condition (p < 0.06), despite no differences in heart rate (HR) or rate of perceived exertion (RPE). Our results show a trend for improvement in time and wattage over the last 16 km of a 64-km simulated TT regardless of glycemic index.
Original languageEnglish
Pages (from-to)466-472
Number of pages7
JournalJournal of Strength and Conditioning Research
Volume18
Issue number3
Publication statusPublished - 2004

Fingerprint

Glycemic Index
Honey
Eating
Gels
Carbohydrates
Glucose
Confidence Intervals
Placebos
Therapeutics
Heart Rate
Weights and Measures

Cite this

Earnest, C. P., Lancaster, S. L., Rasmussen, C. J., Kerksick, C. M., Lucia, A., Greenwood, M. C., ... Kreider, R. B. (2004). Low vs. high glycemic index carbohydrate gel ingestion during simulated 64-km cycling time trial performance. Journal of Strength and Conditioning Research, 18(3), 466-472.

Low vs. high glycemic index carbohydrate gel ingestion during simulated 64-km cycling time trial performance. / Earnest, Conrad P; Lancaster, S L; Rasmussen, C J; Kerksick, C M; Lucia, A; Greenwood, M C; Almada, A L; Cowan, P A; Kreider, R B.

In: Journal of Strength and Conditioning Research, Vol. 18, No. 3, 2004, p. 466-472.

Research output: Contribution to journalArticle

Earnest, CP, Lancaster, SL, Rasmussen, CJ, Kerksick, CM, Lucia, A, Greenwood, MC, Almada, AL, Cowan, PA & Kreider, RB 2004, 'Low vs. high glycemic index carbohydrate gel ingestion during simulated 64-km cycling time trial performance', Journal of Strength and Conditioning Research, vol. 18, no. 3, pp. 466-472.
Earnest CP, Lancaster SL, Rasmussen CJ, Kerksick CM, Lucia A, Greenwood MC et al. Low vs. high glycemic index carbohydrate gel ingestion during simulated 64-km cycling time trial performance. Journal of Strength and Conditioning Research. 2004;18(3):466-472.
Earnest, Conrad P ; Lancaster, S L ; Rasmussen, C J ; Kerksick, C M ; Lucia, A ; Greenwood, M C ; Almada, A L ; Cowan, P A ; Kreider, R B. / Low vs. high glycemic index carbohydrate gel ingestion during simulated 64-km cycling time trial performance. In: Journal of Strength and Conditioning Research. 2004 ; Vol. 18, No. 3. pp. 466-472.
@article{c8f38ce4d38942779dfc65ac296d65ca,
title = "Low vs. high glycemic index carbohydrate gel ingestion during simulated 64-km cycling time trial performance",
abstract = "We examined the effect of low and high glycemic index (GI) carbohydrate (CHO) feedings during a simulated 64-km cycling time trial (TT) in nine subjects ([mean +/- SEM], age = 30 +/- 1 years; weight = 77.0 +/- 2.6 kg). Each rider completed three randomized, double blind, counter-balanced, crossover rides, where riders ingested 15 g of low GI (honey; GI = 35) and high GI (dextrose; GI = 100) CHO every 16 km. Our results showed no differences between groups for the time to complete the entire TT (honey = 128 minutes, 42 seconds +/- 3.6 minutes; dextrose = 128 minutes, 18 seconds +/- 3.8 minutes; placebo = 131 minutes, 18 seconds +/- 3.9 minutes). However, an analysis of total time alone may not portray an accurate picture of TT performance under CHO-supplemented conditions. For example, when the CHO data were collapsed, the CHO condition (128 minutes, 30 seconds) proved faster than placebo condition (131 minutes, 18 seconds; p < 0.02). Furthermore, examining the percent differences and 95{\%} confidence intervals (CI) shows the two CHO conditions to be generally faster, as the majority of the CI lies in the positive range: placebo vs. dextrose (2.36{\%} [95{\%} CI; -0.69, 4.64]) and honey (1.98{\%} [95{\%} CI; -0.30, 5.02]). Dextrose vs. honey was 0.39{\%} (95{\%} CI; -3.39, 4.15). Within treatment analysis also showed that subjects generated more watts (W) over the last 16 km vs. preceding segments for dextrose (p < 0.002) and honey (p < 0.0004) treatments. When the final 16-km W was expressed as a percentage of pretest maximal W, the dextrose treatment was greater than placebo (p < 0.05). A strong trend was noted for the honey condition (p < 0.06), despite no differences in heart rate (HR) or rate of perceived exertion (RPE). Our results show a trend for improvement in time and wattage over the last 16 km of a 64-km simulated TT regardless of glycemic index.",
author = "Earnest, {Conrad P} and Lancaster, {S L} and Rasmussen, {C J} and Kerksick, {C M} and A Lucia and Greenwood, {M C} and Almada, {A L} and Cowan, {P A} and Kreider, {R B}",
year = "2004",
language = "English",
volume = "18",
pages = "466--472",
journal = "Journal of Strength and Conditioning Research",
issn = "1064-8011",
publisher = "NSCA National Strength and Conditioning Association",
number = "3",

}

TY - JOUR

T1 - Low vs. high glycemic index carbohydrate gel ingestion during simulated 64-km cycling time trial performance

AU - Earnest, Conrad P

AU - Lancaster, S L

AU - Rasmussen, C J

AU - Kerksick, C M

AU - Lucia, A

AU - Greenwood, M C

AU - Almada, A L

AU - Cowan, P A

AU - Kreider, R B

PY - 2004

Y1 - 2004

N2 - We examined the effect of low and high glycemic index (GI) carbohydrate (CHO) feedings during a simulated 64-km cycling time trial (TT) in nine subjects ([mean +/- SEM], age = 30 +/- 1 years; weight = 77.0 +/- 2.6 kg). Each rider completed three randomized, double blind, counter-balanced, crossover rides, where riders ingested 15 g of low GI (honey; GI = 35) and high GI (dextrose; GI = 100) CHO every 16 km. Our results showed no differences between groups for the time to complete the entire TT (honey = 128 minutes, 42 seconds +/- 3.6 minutes; dextrose = 128 minutes, 18 seconds +/- 3.8 minutes; placebo = 131 minutes, 18 seconds +/- 3.9 minutes). However, an analysis of total time alone may not portray an accurate picture of TT performance under CHO-supplemented conditions. For example, when the CHO data were collapsed, the CHO condition (128 minutes, 30 seconds) proved faster than placebo condition (131 minutes, 18 seconds; p < 0.02). Furthermore, examining the percent differences and 95% confidence intervals (CI) shows the two CHO conditions to be generally faster, as the majority of the CI lies in the positive range: placebo vs. dextrose (2.36% [95% CI; -0.69, 4.64]) and honey (1.98% [95% CI; -0.30, 5.02]). Dextrose vs. honey was 0.39% (95% CI; -3.39, 4.15). Within treatment analysis also showed that subjects generated more watts (W) over the last 16 km vs. preceding segments for dextrose (p < 0.002) and honey (p < 0.0004) treatments. When the final 16-km W was expressed as a percentage of pretest maximal W, the dextrose treatment was greater than placebo (p < 0.05). A strong trend was noted for the honey condition (p < 0.06), despite no differences in heart rate (HR) or rate of perceived exertion (RPE). Our results show a trend for improvement in time and wattage over the last 16 km of a 64-km simulated TT regardless of glycemic index.

AB - We examined the effect of low and high glycemic index (GI) carbohydrate (CHO) feedings during a simulated 64-km cycling time trial (TT) in nine subjects ([mean +/- SEM], age = 30 +/- 1 years; weight = 77.0 +/- 2.6 kg). Each rider completed three randomized, double blind, counter-balanced, crossover rides, where riders ingested 15 g of low GI (honey; GI = 35) and high GI (dextrose; GI = 100) CHO every 16 km. Our results showed no differences between groups for the time to complete the entire TT (honey = 128 minutes, 42 seconds +/- 3.6 minutes; dextrose = 128 minutes, 18 seconds +/- 3.8 minutes; placebo = 131 minutes, 18 seconds +/- 3.9 minutes). However, an analysis of total time alone may not portray an accurate picture of TT performance under CHO-supplemented conditions. For example, when the CHO data were collapsed, the CHO condition (128 minutes, 30 seconds) proved faster than placebo condition (131 minutes, 18 seconds; p < 0.02). Furthermore, examining the percent differences and 95% confidence intervals (CI) shows the two CHO conditions to be generally faster, as the majority of the CI lies in the positive range: placebo vs. dextrose (2.36% [95% CI; -0.69, 4.64]) and honey (1.98% [95% CI; -0.30, 5.02]). Dextrose vs. honey was 0.39% (95% CI; -3.39, 4.15). Within treatment analysis also showed that subjects generated more watts (W) over the last 16 km vs. preceding segments for dextrose (p < 0.002) and honey (p < 0.0004) treatments. When the final 16-km W was expressed as a percentage of pretest maximal W, the dextrose treatment was greater than placebo (p < 0.05). A strong trend was noted for the honey condition (p < 0.06), despite no differences in heart rate (HR) or rate of perceived exertion (RPE). Our results show a trend for improvement in time and wattage over the last 16 km of a 64-km simulated TT regardless of glycemic index.

UR - http://www.ncbi.nlm.nih.gov/pubmed/15320674/

M3 - Article

VL - 18

SP - 466

EP - 472

JO - Journal of Strength and Conditioning Research

JF - Journal of Strength and Conditioning Research

SN - 1064-8011

IS - 3

ER -