1 / 9

Understanding Controlled Trial Designs in Sports Science Research

This article reviews various controlled trial designs, such as time series, post-only, pre-post, crossover, and their applications in sports science. Key factors influencing the choice of design include subject availability, reliability of measurements, and washout periods. Strengths and weaknesses of each approach are highlighted, along with analytical methods like paired and unpaired t-tests. Researchers are guided through the decision-making process to select the most suitable design while considering sample sizes and potential biases, ensuring robust and reliable findings.

daw
Download Presentation

Understanding Controlled Trial Designs in Sports Science Research

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Controlled-Trial Designs • See Batterham and Hopkins, Sportscience 9, 33-39, 2005. • Choice determined by availability of subjects, reliability of dependent variable, and time to wash out treatment. • Time Series • Weakest design • Any change post treatment could be coincidental. • Analyze using within-subject modeling • Fit line or curve to each subject's baseline. • Extrapolate to the post-test. • Paired t of observed post minus predicted post.

  2. Posts-only Controlled Trial • Least disturbance of subjects • Large sample size, but sample size is smaller than for the usual pre-post designs for variables with sufficiently poor reliability. • Analyze via unequal-variances unpaired t. • Can get estimate of individual responses as an SD, but not usefully for individuals.

  3. washout • Pre-post Controlled Trial (or fully-controlled trial) • Most common design. • Analyze difference of changes via unequal-variances unpaired t. • Pre-post Crossover • Best design if all subjects motivated to know effect of treatment on themselves. • Analyze change of changes via paired t.

  4. washout • Posts-only Crossover • Least number of subjects and tests when reliability high. • But can get estimate of individual responses only if include a repeat of one of the treatments for each subject. • Analyze via paired t. • Important to control for the order effect, if it is substantial and there are unequal numbers in the crossover groups. • A spreadsheet is on its way.

  5. Decision Tree

  6. Can you use a control group or a separate control treatment? NO YES Time-series trial n=10-???

  7. a Is the measure reliable over the intervention period? NO YES Posts - only trial n=2x 150

  8. Will the intervention wash out in an acceptable time for a crossover? NO YES Fully - controlled trial n=2x 10-300 -

  9. b Is the measure reliable over washout+intervention period? NO YES Are you limited by subjects or resources? NO YES Fully - controlled Simple crossover crossover n=10-300 n=10-75

More Related