Effects of High-Intensity Training on Physiological and Hormonal Adaptions in Well-Trained Cyclists

Abstract

. Purpose: This study aimed to compare the effects of three different high-intensity training (HIT) models, balanced for total load but differing in training plan progression, on endurance adaptations. Methods: Sixty-three cyclists (peak oxygen uptake (V O 2peak ) 61.3 T 5.8 mLIkg j1 Imin j1 ) were randomized to three training groups and instructed to follow a 12-wk training program consisting of 24 interval sessions, a high volume of low-intensity training, and laboratory testing. The increasing HIT group (n = 23) performed interval training as 4 Â 16 min in weeks 1-4, 4 Â 8 min in weeks 5-8, and 4 Â 4 min in weeks 9-12. The decreasing HIT group (n = 20) performed interval sessions in the opposite mesocycle order as the increasing HIT group, and the mixed HIT group (n = 20) performed the interval prescriptions in a mixed distribution in all mesocycles. Interval sessions were prescribed as maximal session efforts and executed at mean values 4.7, 9.2, and 12.7 mmolIL j1 blood lactate in 4 Â 16-, 4 Â 8-, and 4 Â 4-min sessions, respectively (P G 0.001). Pre-and postintervention, cyclists were tested for mean power during a 40-min all-out trial, peak power output during incremental testing to exhaustion, V O 2peak , and power at 4 mmolIL j1 lactate. Results: All groups improved 5%-10% in mean power during a 40-min all-out trial, peak power output, and V O 2peak postintervention (P G 0.05), but no adaptation differences emerged among the three training groups (P 9 0.05). Further, an individual response analysis indicated similar likelihood of large, moderate, or nonresponses, respectively, in response to each training group (P 9 0.05). Conclusions: This study suggests that organizing different interval sessions in a specific periodized mesocycle order or in a mixed distribution during a 12-wk training period has little or no effect on training adaptation when the overall training load is the same.

HIIT produces increases in muscle power and free testosterone in male masters athletes

“…Subsequently, we observed increased free-T following the addition of HIIT to this group ( 13 ). Conversely, Sylta and coworkers ( 19 ) reported a decrease in TT and free-T following four-week HIIT in well-trained young cyclists. These authors also reported that PPO increased concomitantly, which would appear counterintuitive given the pervasive belief that muscle power is positively influenced by testosterone.…”

“…HIIT has been shown to improve maximal aerobic power in masters athletes ( 7 ), and PPO and free-T in untrained older participants ( 13 , 20 ). Moreover, HIIT increased PPO, but decreased TT and free-T in young trained participants ( 19 ). However, the effect of HIIT on PPO, TT and free-T in masters athletes is currently unknown.…”

“…These authors also reported that PPO increased concomitantly, which would appear counterintuitive given the pervasive belief that muscle power is positively influenced by testosterone. While Sylta and coworkers ( 19 ) observed decreased testosterone following HIIT in young athletes, the influence of HIIT on androgens of the master athlete remains unknown.…”

Understanding the Effects of Beetroot Juice Intake on CrossFit Performance by Assessing Hormonal, Metabolic and Mechanical Response: A Randomized, Double-Blind, Crossover Design

“…High cortisol levels in response to anaerobic exercise possibly caused a potential for inhibition of testosterone production via steroid inhibition, and thus, cortisol induced a direct suppressive effect on testosterone steroidogenesis [55]. The T/C ratio has been identi ed as an indicator of anabolic/catabolic status during exercise [56]. An absolute ratio less than or equal to 0.35 × 10 − 3 or a decline in the free testosterone to cortisol ratio higher than 30% is suggested to be indicative of a negative catabolic state [57].…”

Influence of Immune and Nutritional Biomarkers on Illness Risk During Interval Training

“…For example, four weeks of longer accumulated HIT duration (4 × 16 min) has been shown to elicit greater improvements in peak power output and peak oxygen consumption (V O2peak) compared to shorter duration HIT (4 × 4 min), despite lower heart rates (HR), blood lactate concentrations, ratings of perceived exertion (RPE) and a less pronounced steroid hormone response. 3 However, it is unclear how different interval training prescriptions influence athletes' health and immune status.…”