NAP: Recovery (2014)
Pritchett, K, Bishop P, Pritchett R, Green M, Katica C. Acute effects of chocolate milk and a commercial recovery beverage on postexercise recovery indices and endurance cycling performance. Appl Physiol Nutr Metab. 2009; 34: 1,017-1,022.
To examine the effects of post-exercise consumption of a CHO replacement beverage (CRB) vs. chocolate milk (CHOC) on indices on muscle damage, CK and muscle soreness, as well as subsequent time to exhaustion.
- Cyclists and triathletes
- Minimum of two years' involvement in endurance sports
- Minimum of six training hours per week
- 19 to 49 years old.
- Younger than 19 years or older than 40 years of age
- Cyclist or triathlete with less than two years of involvement in endurance sports and less than six hours of training per week.
- Recruitment: Not described
- Design: Randomized crossover trial
- Blinding used: Subjects were blinded to the beverage.
- Low fat chocolate milk (CHOC) vs. CHO replacement beverage (CRB) given immediately after the first exercise session and two hours into the recovery period
- The same total amount of CHO was given (1.0g per kg-1 per hour-1) and the beverages were isocaloric (2,488.0±557.9kcal vs. 2,319.6±663.5kcal for CHO vs. CRB, respectively)
- Water, but no other food or beverage were allowed during the recovery period.
- Data as compared using a two-factor (treatment x time) repeated-measures analysis of variance (ANOVA)
- A Tukey's post-hoc test was applied in the case of a significant F-ratio to locate the differences with the ANOVA
- One-way ANOVA for repeated measures was used to compare markers of muscle damage (CK) muscle soreness and performance between trials
- Greenhouse-Geisser corrections were conducted for unequal variance data.
Timing of Measurements
Before and 15 hours to 18 hours after counter-balanced exercise on two occasions, separated by one week.
- Creatine kinase: Capillary blood analyzed on a spectrometer
- Time to exhaustion: On a cycle ergometer at 85% VO2 max until pedal cadence was slower than 60rpm-1 or the participant could no longer continue
- Muscle soreness: 10-cm visual analog scale with "no pain at all" at the left end and "unbearable pain" at the right end.
Low-fat chocolate milk (CHOC) and a CHO replacement drink (CRB).
- A high-intensity workout (five minutes cycling at 60% VO2max warm-up, followed by three 10-second "all out" bicycle Wingate sprints, interspersed with 50-second active recoveries, repeated a total of six times) followed 15 to 18 hours later after recovery with a five-minute warm-up on a bicycle ergometer and then cycled at a pre-determined workload to elicit approximately 85% VO2max until exhaustion
- No coffee or alcohol or exercise for a minimum of 24 hours before testing
- Dietary intake was to be the same between the two trials as before the study (documented by a food frequency questionnaire and three-day food diary, respectively).
- Initial N: 10
- Attrition (final N): 10
- Age: 27.1±7.9 years
- Ethnicity: Not described
- Other relevant demographics: 55.2±7.2ml per kg-1 VO2max and 367.5±38.7W peak watts
- Anthropometrics: 176.5±3.6cm in height; 72.1±6.7kg body weight; 9.2±6.7% body fat
- Location: USA.
- The beverages were identical in CHO and similar in protein and kcals
- The significant difference in fat content (P<0.001) was not enough to significantly affect the difference in overall calorie content between the beverages
- There ware no significant differences in macronutrient intake between the two trials
- Sleep patterns were similar between the two trials
- All of the subjects preferred the taste and consistency of CHOC
- There was no significant difference (P=0.91) between trials for cycling time to exhaustion
- There was no significant difference (P=0.29) for the PRE CK level (CKpre) between the two trials
- A repeated-measures ANOVA revealed a significant (P<0.05) interaction (treatment x time) for change in CKpre to the POST CK level (CKpost)
- A significantly higher (P<0.05) was observed for the CRB trial, however there was no significant difference (P=0.35) for CKpost between the two trials.
- No interaction (treatment x time) for muscle soreness was observed
- There were no significant difference for PRE muscle soreness (P=0.98) and POST muscle soreness (P=0.48) between the two trials
- Subjective measures of muscle soreness decreased significantly (P<0.01) from PRE to POST.
There is no difference between CHOC and this CRB as potential recovery aids for cyclists between intense workouts.
Quality Criteria Checklist: Primary Research
|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|
|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?||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?||N/A|
|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%.)||N/A|
|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.)||N/A|
|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?||N/A|
|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?||N/A|
|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?||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?||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?||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?||Yes|
|10.1.||Were sources of funding and investigators' affiliations described?||Yes|
|10.2.||Was the study free from apparent conflict of interest?||Yes|