CORTISOL REACTS TO CHANGES IN WORKLOAD
Nelson, A. G., Winchester, J. B., Stewart, L. K., & Stone, M. H. (2009). Hormonal markers and physical performance during a peak-taper cycle in elite track and field athletes. ACSM 56th Annual Meeting, Seattle, Washington. Presentation number 2409.
This study investigated the relationship between physical performance and testosterone and cortisol following short term alterations in training volume and intensity. Qualifiers (N = 5) for the 2006 NCAA D-I national track and field meet took part. At the study start, Ss had just finished a peaking training phase prior to competition in a NCAA regional meet. Peaking involved a two-week elevation in training volume/intensity, followed by a one-week reduction in training volume/intensity prior to the regional and national meets. Testing occurred immediately prior to beginning the peaking phase (pre-study), to the onset of the taper cycle (mid-study), and to leaving for the national meet (post-study). All tests were performed at the same time of day, on the same day of the week, and with a minimum of 48 hours prior rest. The performances tested were broad jump and mid-thigh pull. Testosterone and cortisol were determined from saliva samples.
Free testosterone went unchanged throughout the study. Free cortisol rose significantly at mid-study, but returned to pre-study levels at post-study. The testosterone:cortisol ratio also increased at mid-study but returned to pre- study levels at post-study. Significant correlations were observed between testosterone and the broad jump, peak force, and rate of force development for pre- study and mid-study, and with the broad jump and rate of force development at post-study. Significant negative correlations were registered between cortisol and broad jump and rate of force development during pre-study, and with rate of force development during mid- study and post-study. Significant correlations were observed between the testosterone:cortisol ratio and broad jump and rate of force development during pre-study, with peak force at mid-study, and with broad jump, peak force, and rate of force development at post-study.
Implication. Athletes increased training volume for two weeks and showed a significant increase in cortisol. When training volume was tapered, cortisol decreased accordingly. However, testosterone showed no significant alterations to either the sudden increase in the training or the tapering and cessation of training. Testosterone, cortisol, and the testosterone:cortisol ratio were significantly related to the physical performance indicators of broad jump, peak force, and rate of force development.
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