This paper is a meta-analysis of the role of nutritional supplements in strength training focusing on the effects of placebo treatments. We address specifically the results from meta-analysis of 334 fi.ndings from 37 studies of the effect of nutritional supplements and physical fitness interventions on strength, stamina, and endurance outcomes, controlling for main effects of the group on which the results were obtained (placebo, treatment, control, for pretest or posttest), with covariates for age, gender, randomization, double-blind procedures, study duration, training load, training frequency, and training status. Finding show that there are significant placebo effects accounting for a substantial portion of the effect size typically associated with treatment interventions. In addition to produce the best evaluations of treatment effects, both control and placebo groups should be included in a double-blind research design using participants who are well familiarized with the study procedures.
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Meta-Analysis of the Placebo Effect in Nutritional Supplement Studies of Muscular Performance
Tarra Rawdon, Rick L. Sharp, Mack Shelley, and Jerry R. Thomas
Potential Role of Plyometric Training in the Development of Motor Performance Skills: A Narrative Review
Andrew Sortwell, Michael Newton, Daniel A. Marinho, Jorge Knijnik, and Rodrigo Ramirez-Campillo
training loads are required to develop motor performance skill capacities, such as power, speed, and strength, necessary to develop proficiency ( Stricker et al., 2020 ). This problem is evident in Australian PE curriculum; teachers must cover different motor skills (predefined) through the process of
