EAL

NAP: Recovery (2007)

Citation:

Haub MD, Potteiger JA, Jacobsen DJ, Nau KL, Magee LA, Comeau MJ. Glycogen replenishment and repeated maximal effort exercise: effect of liquid carbohydrate. Int J Sport Nutr. 1999 Dec; 9 (4): 406-415.

PubMed ID: 10660871

Study Design:

Randomized Controlled Trial

Class:

A - Click here for explanation of classification scheme.

Quality Rating:

NEUTRAL: See Quality Criteria Checklist below.

Research Purpose:

To determine the effects of CHO ingestion during 60 minutes of recovery from short-duration high-intensity exercise.

Inclusion Criteria:

Exercising for at least three days a week for three months prior to testing.

Exclusion Criteria:

Not stated.

Description of Study Protocol:

Recruitment: Not stated.
Design: Counter-balanced, randomized trial
Three testing occasions
- Test One was to determine VO_2peak and familiarize with the 100-kJ protocol
- In Tests Two and Three, participants performed a 100-kJ test, consumed one of the two treatment beverages, rested for 60 minutes and then completed a second 100-KJ test. Testing sessions were separated by six, but not more than eight days.
Blinding used: Double-blind
Intervention: 20% solution of 0.7g per kg body mass maltodextrin (Gatorade) or an equal volume of placebo (aspartame) matched for taste
Statistical analysis
- Time to complete the 100-KJ test was compared between treatments using dependent T-tests
- Energy and CHO were compared using dependent T-tests.

Data Collection Summary:

Timing of Measurements

Subjects were tested on three occasions
Initial testing session to determine VO_2peak and Testing Sessions Two and Three were treatment conditions.

Dependent Variables

Time to complete the work (seconds)
VO_2max (L per minute)
Muscle tissue was analyzed for glycogen concentration
Blood samples were analyzed for lactate, hemoglobin and hematocrit
Subjects abstained from exercise for 24 hours prior to all testing.

Independent Variables

20% solution of 0.7g per kg body mass maltodextrin (Gatorade) or an equal volume of placebo (aspartame) matched for taste
Refrained from consuming caffeine or alcohol for 24 hours prior to testing
Diet was self-recorded for 48 hours prior to first assigned treatment.

Control Variables

None stated.

Description of Actual Data Sample:

Initial N: Six males
Attrition (final N): Six males
Age (mean±SD): 25.0±4.6 years
Ethnicity: Not stated.
Other relevant demographics (means±SD): Weight, 73.5±5.6kg; height, 181.0±5.6cm; VO_2peak, 50.8±6.0ml per kg per minute
Location: Kansas.

Summary of Results:

Variables	CHO (means±SD)	Placebo (means±SD)	Statistical Significance of Group Difference
Time to complete work during Ride One (seconds)	323.0±38.3	317.8±32.6	NS
Time to complete work during Ride Two (seconds)	330.0±33.3	338.0±25.5	P<0.05

Other Findings

No significant difference for CHO groups between Rides One and Two, but a significant increase in run time was reported between Ride One and Ride Two for the placebo group
There were no significant differences between treatments for total energy intake or carbohydrate consumption for the 48 hours prior to testing.

Author Conclusion:

In summary, the ingestion of carbohydrates following short-duration, high-intensity exercise does not significantly enhance glycogen resynthesis during the first hour post-exercise or affect subsequent short-duration, high-intensity exercise. However, carbohydrate ingestion during 60 minutes of recovery from short-duration, high-intensity exercise significantly alters circulating plasma glucose concentration and seems to minimize the significant performance decrement observed following a placebo solution.

Funding Source:

Industry:

Gatorade Sports Science Institute

Food Company:

University/Hospital:

University of Kansas

Reviewer Comments:

Recruitment methods, inclusion criteria and exclusion criteria were not well-defined.

Quality Criteria Checklist: Primary Research
Relevance Questions
	1.	Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies)	Yes
	2.	Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about?	Yes
	3.	Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice?	Yes
	4.	Is the intervention or procedure feasible? (NA for some epidemiological studies)	Yes

Validity Questions
1.	Was the research question clearly stated?		Yes
	1.1.	Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified?	Yes
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	Yes
	1.3.	Were the target population and setting specified?	???
2.	Was the selection of study subjects/patients free from bias?		???
	2.1.	Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study?	No
	2.2.	Were criteria applied equally to all study groups?	???
	2.3.	Were health, demographics, and other characteristics of subjects described?	Yes
	2.4.	Were the subjects/patients a representative sample of the relevant population?	???
3.	Were study groups comparable?		N/A
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	N/A
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	N/A
	3.3.	Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.)	N/A
	3.4.	If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis?	N/A
	3.5.	If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.)	N/A
	3.6.	If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?	N/A
4.	Was method of handling withdrawals described?		Yes
	4.1.	Were follow-up methods described and the same for all groups?	Yes
	4.2.	Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.)	Yes
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	Yes
	4.4.	Were reasons for withdrawals similar across groups?	N/A
	4.5.	If diagnostic test, was decision to perform reference test not dependent on results of test under study?	N/A
5.	Was blinding used to prevent introduction of bias?		Yes
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	Yes
	5.2.	Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.)	Yes
	5.3.	In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?	N/A
	5.4.	In case control study, was case definition explicit and case ascertainment not influenced by exposure status?	N/A
	5.5.	In diagnostic study, were test results blinded to patient history and other test results?	N/A
6.	Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described?		Yes
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	Yes
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	N/A
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	Yes
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	Yes
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	N/A
	6.6.	Were extra or unplanned treatments described?	N/A
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	???
	6.8.	In diagnostic study, were details of test administration and replication sufficient?	N/A
7.	Were outcomes clearly defined and the measurements valid and reliable?		Yes
	7.1.	Were primary and secondary endpoints described and relevant to the question?	Yes
	7.2.	Were nutrition measures appropriate to question and outcomes of concern?	Yes
	7.3.	Was the period of follow-up long enough for important outcome(s) to occur?	Yes
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	Yes
	7.5.	Was the measurement of effect at an appropriate level of precision?	Yes
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	???
	7.7.	Were the measurements conducted consistently across groups?	???
8.	Was the statistical analysis appropriate for the study design and type of outcome indicators?		Yes
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	Yes
	8.2.	Were correct statistical tests used and assumptions of test not violated?	N/A
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	Yes
	8.4.	Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)?	???
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	N/A
	8.6.	Was clinical significance as well as statistical significance reported?	Yes
	8.7.	If negative findings, was a power calculation reported to address type 2 error?	N/A
9.	Are conclusions supported by results with biases and limitations taken into consideration?		Yes
	9.1.	Is there a discussion of findings?	Yes
	9.2.	Are biases and study limitations identified and discussed?	Yes
10.	Is bias due to study's funding or sponsorship unlikely?		???
	10.1.	Were sources of funding and investigators' affiliations described?	Yes
	10.2.	Was the study free from apparent conflict of interest?	???