NAP: Energy Balance and Body Composition (2007)

Citation:

Finn KJ, Dolgener FA, Williams RB. Effects of carbohydrate refeeding on physiological responses and psychological and physical performance following acute weight reduction in collegiate wrestlers. J Strength Cond Res. 2004; 18 (2): 328-333. 

PubMed ID: 15142030
 
Study Design:
Randomized controlled trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

Finn KJ, Dolgener FA, Williams RB. Effects of carbohydrate refeeding on physiological responses and psychological and physical performance following acute weight reduction in collegiate wrestlers. J Strength Cond Res. 2004; 18 (2): 328-333.

Inclusion Criteria:
  • Members of the University of Northern Iowa collegiate wrestling team
  • Recruited one month prior to their weight certification date
  • Each subject was required to undergo a four-day familiarization period to orient the subjects to the arm crank test. 
Exclusion Criteria:
Heavyweight wrestlers were excluded. 
Description of Study Protocol:
  • Recruitment: From the University of Northern Iowa wrestling team.
  • Design: Randomized controlled trial, split group, repeated-measures design.
  • Blinding used: Not discussed in article.
  • Intervention: Ingestion of either 1.5g CHO per kg body weight in a 25% concentration administered in one-L bottles or placebo (containing 0g CHO).

Statistical Analysis

  • Repeated-measures ANOVA for the interaction between time and intermittent sprint work, blood lactate response, positive affect scores and negative affect scores
  • Paired T-test for between group comparisons.  
Data Collection Summary:

Timing of Measurements

Baseline, weigh-in (three to five days after baseline measures), two hours post-treatment.

Dependent Variables

  • Intermittent sprint power and work: Measured via arm crank test. A Monark 814E cycle ergometer was mounted and secured to a table and the foot pedals were replaced with hand grips. Arm work and power was measured trhgouh the Opto-Sensor, Model 2000 
  • Blood lactate response: A 75uL blood sample was taken immediately before and after the arm crank test and analyzed for lactate levels
  • Mood: Measured through the Positive and Negative Affect Schedule (PANAS) survey instrument.

Independent Variables

Presence of treatment intervention (CHO beverage or placebo).
Description of Actual Data Sample:
  • Initial N: 18
  • Attrition (final N): 15; three subjects did not complete Trials Two (weigh-in) and Three (post-treatment)
  • Age (mean±SD): 20.80±1.78
  • Ethnicity: Not discussed.

Other Relevant Demographics

  • Baseline weight (mean±SD): 74.96±9.18kg
  • Body fat percentage (mean±SD): 10.01±1.82.

Anthropometrics

  • Data was only presented for whole population, not individual groups
  • There was no significant difference in certification body mass between groups, no other demographics described.

Location

Cedar Falls, Iowa.

Summary of Results:

Mean (SD) Work, Lactate Response and Mood Data by Group and Trial

 
Trial
Work (kJ)
Lactate Response (mM)
Positive Affect
Negative Affect
Treatment
Baseline
36.88 (5.16)
6.97 (1.06)
25.75 (7.40)
15.50 (4.41)
Weigh-In
37.84 (6.01)
6.77 (1.57)
23.63 (5.50)
14.13 (3.68)
Post-treatment
37.37 (5.95)
5.77 (1.16)
25.00 (4.60)
12.00 (2.33)
Placebo
Baseline
37.18 (6.83)
7.07 (1.36)
28.14 (9.46)
17.71 (7.04)
Weigh-In
35.38 (6.17)
6.66 (1.78)
24.86 (10.53)
17.86 (7.36)
Post-treatment
36.03 (6.27)
6.41 (2.00)
24.00 (11.02)
15.71 (4.79)

Correlation Coefficients Between Sprint Work and Lactate Response *P<0.05

 
 
Sprint 1
Sprint 2
Sprint 3
Lactate 1
Lactate 2
Lactate 3
Sprint 1
1.000
0.883*
0.885*
0.199
0.436
0.274
Sprint 2
0.883*
1.000
0.976*
0.251
0.542*
0.203
Sprint 3
0.885*
0.976*
1.000
0.334
0.562*
0.307
Lactate 1
0.199
0.251
0.334
1.000
0.785*
0.861*
Lactate 2
0.436
0.542*
0.562*
0.785*
1.000
0.807*
Lactate 3
0.274
0.203
0.307
0.861*
0.807*
1.000

Additional Findings

  • Both groups lost a significant (P<0.001) amount of body mass during the weight reduction period.
Author Conclusion:
The results of this study suggest that intermittent sprint work, blood lactate response and mood was not positively affected by ingestion of carbohydrates, following an acute weight reduction period.
Funding Source:
University/Hospital: University of Northern Iowa
Reviewer Comments:
  • Randomization to groups not described
  • Group comparisons not described
  • Statistical power limited, based on small sample size.
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? Yes
  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? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  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? Yes
3. Were study groups comparable? ???
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) No
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? ???
  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? ???
  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? ???
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? ???
  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.) ???
  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? 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)? Yes
  8.6. Was clinical significance as well as statistical significance reported? ???
  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