Mixed maximal and explosive strength training in recreational endurance runners.

Supervised periodized mixed maximal and explosive strength training added to endurance training in recreational endurance runners was examined during an 8-week intervention preceded by an 8-week preparatory strength training period. Thirty-four subjects (21-45 years) were divided into experimental groups: men (M, n = 9), women (W, n = 9), and control groups: men (MC, n = 7), women (WC, n = 9). The experimental groups performed mixed maximal and explosive exercises, whereas control subjects performed circuit training with body weight. Endurance training included running at an intensity below lactate threshold. Strength, power, endurance performance characteristics, and hormones were monitored throughout the study. Significance was set at p ≤ 0.05. Increases were observed in both experimental groups that were more systematic than in the control groups in explosive strength (12 and 13% in men and women, respectively), muscle activation, maximal strength (6 and 13%), and peak running speed (14.9 ± 1.2 to 15.6 ± 1.2 and 12.9 ± 0.9 to 13.5 ± 0.8 km L h). The control groups showed significant improvements in maximal and explosive strength, but Speak increased only in MC. Submaximal running characteristics (blood lactate and heart rate) improved in all groups. Serum hormones fluctuated significantly in men (testosterone) and in women (thyroid stimulating hormone) but returned to baseline by the end of the study. Mixed strength training combined with endurance training may be more effective than circuit training in recreational endurance runners to benefit overall fitness that may be important for other adaptive processes and larger training loads associated with, e.g., marathon training.

Heart rate-running speed index may be an efficient method of monitoring endurance training adaptation.

The aim of this study was to investigate whether a novel heart rate (HR)-running speed index could be used in monitoring adaptation to endurance training. Forty-five recreational runners underwent a 2-phased 28-week training regime. The first 14 weeks included basic endurance training, whereas the second 14 weeks were more intensive (increased volume and intensity). A maximal treadmill running test was performed in the beginning of the experiment, in the middle of basic endurance training, and at the end of each training period (PRE, WEEK 7, WEEK 14, and POST). The novel HR-running speed index was calculated from every continuous-type running exercise during the 28-week experiment based on exercise HR-running speed relation accompanied by individual information on resting and maximal HR and speed. The change in the novel index correlated significantly with the changes of peak running speed in the treadmill tests (r = 0.43-0.61, p < 0.01) and speed at respiratory compensation threshold (r = 0.35-0.39, p ≤ 0.05) during the experiment. The change in the index also correlated significantly (r = 0.49, p = 0.001) with relative changes in maximal oxygen uptake (in ml·kg·min). According to these findings, it seems that the novel index based on exercise HR and running speed may serve as a practical tool for daily monitoring of individual's training adaptation without the need to realize a maximal running test in laboratory conditions.

Effects of vigorous late-night exercise on sleep quality and cardiac autonomic activity.

Sleep is the most important period for recovery from daily load. Regular physical activity enhances overall sleep quality, but the effects of acute exercise on sleep are not well defined. In sleep hygiene recommendations, intensive exercising is not suggested within the last 3 h before bed time, but this recommendation has not been adequately tested experimentally. Therefore, the effects of vigorous late-night exercise on sleep were examined by measuring polysomnographic, actigraphic and subjective sleep quality, as well as cardiac autonomic activity. Eleven (seven men, four women) physically fit young adults (VO(2max) 54±8 mL·kg(-1)·min(-1) , age 26±3 years) were monitored in a sleep laboratory twice in a counterbalanced order: (1) after vigorous late-night exercise; and (2) after a control day without exercise. The incremental cycle ergometer exercise until voluntary exhaustion started at 21:00±00:28 hours, lasted for 35±3 min, and ended 2:13±00:19 hours before bed time. The proportion of non-rapid eye movement sleep was greater after the exercise day than the control day (P<0.01), while no differences were seen in actigraphic or subjective sleep quality. During the whole sleep, no differences were found in heart rate (HR) variability, whereas HR was higher after the exercise day than the control day (54±7 versus 51±7, P<0.01), and especially during the first three sleeping hours. The results indicate that vigorous late-night exercise does not disturb sleep quality. However, it may have effects on cardiac autonomic control of heart during the first sleeping hours.