NAP: Competition (2007)

Citation:

el Sayed MS, Rattu AJM, Lin X, Reilly T.  Effects of active warm down and carbohydrate feeding on free fatty acid concentrations after prolonged submaximal exercise.  Int J Sports Nutr 1996;6(4):337-347.

PubMed ID: 8953336
 
Study Design:
Randomized Crossover Trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:
To examine the effects of active warm-down and carbohydrate ingestion on free fatty acid concentrations and glucose changes into recovery following prolonged submaximal exercise.
Inclusion Criteria:
Apparently healthy, nonsmoking male cyclists.
Exclusion Criteria:
None specifically mentioned.
Description of Study Protocol:

Recruitment

Subjects volunteered.

Design

Randomized Crossover Trials.

Blinding used (if applicable)

Single blind - lab tests.

Intervention (if applicable)

On 3 trials separated by 7 days, subjects in Group 1 cycled at 70% of maximal oxygen uptake; 7.5% carbohydrate or placebo was ingested 15 minutes before (5 ml/kg body weight), immediately before (3.5 ml/kg) and 45 minutes during exercise (3.5 ml/kg).  In the active warm down experiment, exercise was followed immediately by an active warm down and 5 subjects were given a placebo solution.  On 2 trials separated by 7 days, group 2 subjects consumed 7.5% carbohydrate or placebo at 75 minutes during (5 ml/kg) and after exercise at 70% VO2max (5 ml/kg).  The amounts of carbohydrate and volumes of fluid given were 65.0 +/- 2.1 g and 856 +/- 26.3 ml in Group 1 and 31 +/- 0.9 g and 410 +/- 12.3 ml in Group 2.

Statistical Analysis

Data analyzed with 2-way ANOVA with repeated measures.  When ANOVA showed a significant difference, the Tukey post hoc test was employed to ascertain which mean values were statistically significant.

Data Collection Summary:

Timing of Measurements

Body weight measured before and after each trial.  Venous blood samples obtained at rest (15 minutes before and 15 minutes after administration of drink), at 35 and 90 minutes during exercise, and at 10, 20 and 30 minutes of recovery in Group 1.  In Group 2, blood samples were drawn at rest, at 45 minutes during exercise, at completion of exercise, and at 10, 20 and 30 minutes of recovery.

Dependent Variables

  • Body weight
  • Blood samples analyzed for lactate, hemoglobin, hematocrit, glucose and free fatty acids

Independent Variables

  • Group 1 ingested carbohydrate or placebo 15 minutes before and 45 minutes during exercise
  • In the active warm down experiment, exercise was followed immediately by an active warm down and 5 subjects were given a placebo solution
  • Group 2 subjects consumed carbohydrate or placebo at 75 minutes during and after exercise
  • Subjects asked to maintain normal diets 48 hours prior and not engage in vigorous exercise on day before testing
  • Refrain from food and fluid for 4 hours prior to testing

Control Variables

 

Description of Actual Data Sample:

Initial N: 15 males.  9 subjects in Group 1, 6 in Group 2.

Attrition (final N):  15

Age:  Group 1 mean age 21.0 +/- 0.7 years, Group 2 mean age 22.5 +/- 0.7 years

Ethnicity:  not mentioned

Other relevant demographics:

Anthropometrics:

Location:  United Kingdom

 

Summary of Results:

Other Findings

No differences were found in Group 1 between carbohydrate and placebo trials in the mean values of heart rate, blood lactate, or plasma volume loss.

There was a significant decrease in blood glucose levels during exercise and recovery only in Group 1, with a concomitant increase in FFA concentrations during exercise in both groups.

Carbohydrate ingestion in groups 1 and 2 significantly decreased the normal response of FFAs during exercise and markedly reduced the normal elevation of FFAs in recovery.

Active warm down following submaximal exercise had no effect on plasma FFA elevations in recovery. 

Author Conclusion:
In summary, this study demonstrated that carbohydrate ingestion, but not active warm-down, attenuates FFA elevations in recovery after prolonged exercise.
Funding Source:
University/Hospital: Liverpool John Moores University
Reviewer Comments:
Inclusion/exclusion criteria and recruitment methods not well defined.  No power calculations done.
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? Yes
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? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  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? No
  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? Yes
  6.6. Were extra or unplanned treatments described? Yes
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  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? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? ???
  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? Yes
  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)? N/A
  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? No
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? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes