BACKGROUND:The purpose of the present study was to examine the effects of time-ofday-strength training on plasma testosterone (T) and cortisol (C) concentrations in male amateur athletes. METHODS: Forty five male athletes (age, 21.2±0.3 years; height, 1.75±0.14 m; weight, 72±1.52 kg) participated in the present study. They were subjected to strength training of the knee extensor and flexor muscles. Following this, they were randomly assigned into three groups: morning strength training group (MSTG, 07:00-08:00 hours, n=15), afternoon strength training group (ASTG, 16:00-17:00 hours, n=15) and morning and afternoon strength training group (MASTG, 07:00-08:00 and 16:00-17:00 hours, n=15). The concentration of T and C for each athlete was collected in all three conditions in the morning, noon and afternoon, before and after 8 weeks of strength training. The effects of group, time of the day and pre-to post-training were verified by a 3-way analysis of variance with repeated measures. RESULTS: Our results indicate that strength training induces an increase of plasma T/C ratio in both groups of athletes who have always trained for only one session per day mainly in the afternoon compared with the MASTG (P < 0.05). However, a reduction of the plasma T/C ratio was observed in the athletes who have always trained successively in the morning and in the afternoon (P < 0.05). Plasma T/C ratio exhibit circadian rhythmicity in all groups showing a low level in the morning, whereas in the afternoon an increased value was more noted (P < 0.05). CONCLUSIONS: From an applied perspective, this study suggests that amateur athletes should train at the afternoon to maximize their performance gain.

Background: The objectives of this systematic review and meta-analysis were to quantify the effectiveness of endurance training (ET) on aerobic performance (i.e., peak oxygen uptake (VO2peak)) in healthy and unhealthy middle and very old adults aged 70 years and older, and to provide dose–response relationships of training prescription variables (in terms of frequency, and volume). Methods: Several scholarly databases (i.e., PubMed/MEDLINE, SpringerLink, ScienceDirect Journals, and Taylor & Francis Online—Journals) were searched, identifying randomized controlled studies that investigated the effectiveness of ET on VO2peak in older adults. Standardized mean differences (SMD) were calculated. Results: In terms of changes differences between experimental and control group, ET produced significant large effects on VO2peak performance (SMD = 2.64 (95%CI 0.97–4.31)). The moderator analysis revealed that “health status” variable moderated ET effect onVO2peak performance. More specifically, ET produced larger SMD magnitudes on VO2peak performance in healthy compared with unhealthy individuals. With regard to the dose–response relationships, findings from the meta-regression showed that none of the included training prescription variables predicted ET effects on VO2peak performance. Conclusions: ET is an effective mean for improving aerobic performance in healthy older adults when compared with their unhealthy counterparts.