This study consists of two training experiments using a mechanically braked cycle ergometer. First, the effect of 6 wk of moderate-intensity endurance training (intensity: 70% of maximal oxygen uptake (˙VO_2max), 60 min·d^-1, 5 d·wk^-1) on the anaerobic capacity (the maximal accumulated oxygen deficit) and ˙VO_2max was evaluated. After the training, the anaerobic capacity did not increase significantly(P > 0.10), while ˙VO_2max increased from 53 ± 5 ml·kg^-1·min^-1 to 58 ± 3 ml·kg^-1·min^-1 (P < 0.01) (mean± SD). Second, to quantify the effect of high-intensity intermittent training on energy release, seven subjects performed an intermittent training exercise 5 d·wk^-1 for 6 wk. The exhaustive intermittent training consisted of seven to eight sets of 20-s exercise at an intensity of about 170% of ˙VO_2max with a 10-s rest between each bout. After the training period, ˙VO_2max increased by 7 ml·kg^-1·min^-1, while the anaerobic capacity increased by 28%. In conclusion, this study showed that moderate-intensity aerobic training that improves the maximal aerobic power does not change anaerobic capacity and that adequate high-intensity intermittent training may improve both anaerobic and aerobic energy supplying systems significantly, probably through imposing intensive stimuli on both systems.

Background— Reductions in the compliance of central arteries exert a number of adverse effects on cardiovascular function and disease risk. Endurance training is efficacious in increasing arterial compliance in healthy adults. We determined the effects of resistance training on carotid arterial compliance using the intervention study design. Methods and Results— Twenty-eight healthy men 20 to 38 years old were randomly assigned to the intervention group (n=14) and the control group (n=14). Control subjects were instructed not to alter their normal activity levels throughout the study period. Intervention subjects underwent 3 supervised resistance training sessions per week for 4 months and detraining for a subsequent 4 months. The resistance training increased maximal strength in all muscle groups tested ( P <0.001). There were no significant differences in baseline arterial compliance and β-stiffness index between the intervention and control groups. In the intervention group, carotid arterial compliance decreased 19% ( P <0.05), and β-stiffness index increased 21% ( P <0.01) after resistance training. These values returned completely to the baseline levels during the detraining period. Arterial compliance did not change in the control group. In both groups, there were no significant changes in brachial and carotid blood pressure, carotid intima-media thickness, lumen diameter, and femoral arterial compliance. Changes in carotid artery compliance were significantly and negatively related to corresponding changes in left ventricular mass index ( r =−0.56, P <0.001) and left ventricular hypertrophy index ( r =−0.68, P <0.001). Conclusions— In marked contrast to the beneficial effect of regular aerobic exercise, several months of resistance training “reduces” central arterial compliance in healthy men.

Background: Regular aerobic exercise prevents and reverses arterial stiffening, but the association between resistance training and arterial stiffness is unclear.Aim: This study was performed to conduct a systematic review and meta-analysis of randomised controlled clinical trials (RCTs) assessing the associations between resistance training and changes in arterial stiffness.Methods: MEDLINE and SPORTDiscus databases were searched from January 1980 through to April 2011. RCTs evaluating the ability of resistance training to increase arterial stiffness in comparison with a control group were included in the meta-analysis. Two independent reviewers extracted data and assessed the quality of the included studies. Data from 185 reports of eight RCTs (193 participants) were included. Pooled mean differences in arterial stiffness indices (carotid arterial β stiffness and pulse wave velocity (PWV)) between intervention and control groups were calculated using a random-effects model.Results: The overall association of resistance training versus control with relative changes in carotid β index or PWV (eight studies; 193 participants) was 10.7% (95% CI 3.4% to 18.0%; I², 89%; heterogeneity, p<0.001). Five studies indicated that resistance training in young subjects (n=115) was significantly associated with an increase in stiffness index of 14.3% (95% CI 8.5% to 20.1%; I², 71%; heterogeneity, p<0.001) compared with controls. However, three studies showed that resistance training in middle-aged subjects (n=78) was not associated with changes in arterial stiffness. In addition, although high-intensity resistance training (n=87) was significantly associated with an increase in stiffness of 11.6%, moderate-intensity resistance training (n=106) showed no such association.Conclusion: High-intensity resistance training is associated with increased arterial stiffness in young subjects with low baseline levels of arterial stiffness.