Grant Alex Curtis

Why? The purpose of this study was to examine the net hormonal effect of amino acid supplementation on the overreaching resistance training-induced hormonal stress response.

Variables Independent variable- Amino acid (BCAA) supplementation Dependant variables- Testosterone, Creatine kinase, and Cortisol levels

Brief Summary Amino acid supplement or placebo was taken twice daily for 4 weeks. During Week 4, high-intensity resistance training was added throughout that week. Blood draws were taken 5 times for each 4-week period. Testosterone, cortisol, and creatine kinase levels were assessed before, during, and after.

Hypothesis Amino acid supplementation during overreaching would result in a net anabolic hormonal profile as a response to reduced skeletal muscle damage or enhanced recovery.

Structure A balanced, cross-over, placebo-controlled, double-blind, repeated-measures design.

Relationships Key relationships to understand: Testosterone when there is enhanced skeletal muscle repair Cortisol when hormonal stress response is reduced Creatine kinase when skeletal muscle repaired is enhanced

Results

External Validity Is this experiment generalizing to a specific group or population? Generalized to healthy active males with previous resistance training, to be exact athletes would be the correct term. Positive relationship is the increase in testosterone levels Negative relationship is the decrease in Serum Cortisol and Creatine Kinase levels. The participants were selected from a sample of convenience, from a university. Non-probabilistic study Is a volunteer study

Internal Validity Multiple group threats Reasonable number of participants- the study started out with 10 people in the study and ended with only 8. Selection mortality threat- Two of the participants dropped put of the study. May not be a threat be though because both the drop outs were random. Positives The experiment does a good job of not having any testing threats. There are multiple pre and post tests through out the experiment. It’s a fair and balanced study because both groups receive the placebo and the amino acids.

Construct Validity Face and Content Validity Relationships Mono operation bias Diet-protein Amino supplement proportions