Showing papers on "Interval training published in 1995"
TL;DR: To determine whether plasma glutamine levels can be used as an indicator of exercise‐induced stress, and to consider the possible effects of low plasma glutamines concentrations on the immune system, a large number of animals were studied.
Abstract: OBJECTIVE: To determine whether plasma glutamine levels can be used as an indicator of exercise-induced stress, and to consider the possible effects of low plasma glutamine concentrations on the immune system. METHODS: We used two exercise regimens: in Trial 1 seven male subjects were randomly stressed on a treadmill at 0, 30%, 60%, 90% and 120% of their maximal oxygen uptake (VO2max); in Trial 2 five highly trained male subjects underwent intensive interval training sessions twice daily for ten days, followed by a six-day recovery period. RESULTS: Plasma glutamine concentrations decreased significantly from an average of 1244 +/- 121 mumol/L to 702 +/- 101 mumol/L after acute exercise at 90% VO2max (P < 0.05) and to 560 +/- 79 mumol/L at 120% VO2max (P < 0.001). Four of the five subjects showed reduced plasma glutamine concentrations by Day 6 of the overload training trial, with all subjects displaying significantly lower glutamine levels by Day 11. However, glutamine levels showed a variable rate of recovery over the six-day recovery period, with two subjects' levels remaining low by Day 16. CONCLUSIONS: Reduced plasma glutamine concentrations may provide a good indication of severe exercise stress.
111 citations
TL;DR: The data suggest that the type of interval training program used in the study increased aerobic power and also enhanced performance in repeated high intensity, short duration work.
Abstract: The effects of a 9-week aerobic interval training program on anaerobic intermittent performance were investigated. Intermittent work consisted of four repeat 30-sec maximal efforts on a cycle ergom...
39 citations
TL;DR: Child athletes have a low ability to generate high-intensity anaerobic power and their local muscular endurance is low compared with that of adult athletes, and their daily training volume and intensity should be curtailed more so than in adults.
Abstract: Child athletes have a low ability to generate high-intensity anaerobic power and their local muscular endurance is low compared with that of adult athletes. This is reflected in children's low performance in short and long sprints, jumps and throwing events. On the other hand, children achieve steady-state at the start of intense exercise and recover more quickly than adults following intense exercise. A practical implication is that, during high-intensity interval training, children may need shorter resting periods than adults. Children take longer than adults to acclimate or acclimatize to heat. Upon transition to a warmer climate, their daily training volume and intensity should therefore be curtailed more so than in adults. Compared with adults, children thermoregulate less effectively during dehydration. Adequate fluid replenishment is therefore paramount for the child athlete. Flavouring the fluid is one means of enhancing young athletes' drinking volume. It is possible that adding sodium and chloride to the drink will further enhance drinking volume.
28 citations
TL;DR: Results indicate that training with short intervals at the velocity producing a lactate level of 4 mmol/l (VLA4) is sufficient to induce adaptations and better exercise tolerance related parameters.
Abstract: Summary
The purpose of this study was to determine if training with short intervals at the velocity producing a lactate level of 4 mmol/l (VLA4) is sufficient to induce adaptations and better exercise tolerance. Five Standardbred mares (4–8 years) were interval trained on a treadmill 3 days a week for 12 weeks and subsequently detrained for 4 weeks. Standardized exercise tests were performed before, during and after the training period and muscle biopsies were taken. Measurements were made of heart rate, oxygen consumption, stride frequency, blood volume and blood lactate.
Plasma volume was reduced after 2 weeks of training but then increased to the approximate pre-training value throughout the remaining training and post-training periods. No change was detected in the total cell volume whereas the total blood volume varied in consequence with the plasma volume variation. A significant reduction in heart rate response to exercise was seen after 4 weeks of training. VLA4 increased after 2 weeks of training and remained higher than the baseline value during the rest of the training period. Consequently, the blood lactate at 8 m/sec was decreased compared to baseline concentration after 8 and 12 weeks of training. The post-training VLA4 did not differ significantly either from the end of training or from the pre-training value. Mass specific oxygen consumption (VO2-200/BW) at V200 increased with training and decreased with detraining. The respiratory quotient at a velocity of 8 m/sec decreased from 1.18 ± 0.02 before training to 1.07 ± 0.02 (P < 0.05) at the end of training. No changes were found in muscle histo- or biochemical parameters. The results indicate that training at VLA4 is sufficient to cause adaptational changes in exercise tolerance related parameters.
18 citations
TL;DR: It is concluded that 40-60 years old healthy human subjects performing anaerobic training experience on average a significant decrease of circulating CD4+ T-lymphocytes, while other parameters including the activation parameters sCD8 and sCD4 remained unchanged.
Abstract: In 13 middle-aged, moderately trained men (40-60 yr) we investigated the influence of anaerobic training on immunological parameters measured at rest. The 4 week anaerobic training program (two 30-min sessions weight lifting and one interval training per week; lactate levels 4-6 mM and 8-10 mM, respectively), caused a significant increase of the mean arm muscle force by 7% (handgrip test, p < 0.05). Evaluation of lymphocyte subsets was performed by means of three-colour immunofluorescence analysis (FACS). After 4 weeks of training we found a significant reduction of the CD4+ T-cell counts by 15% (p < 0.05) paralleled by a fall of naive cells (CD3+/ CD4+/ CD45RA+) by 16%, which, however, was statistically not significant. While percentages of CD3+ lymphocytes decreased significantly by 6% (p < 0,001), absolute numbers of CD3+ T-lymphocytes were not detectably affected and also the relative ratio of CD8+ T-cell subsets, i.e. the ratio of suppressor vs cytotoxic T-cells (CD3+/CD8+/CD11b+, CD3+/CD8+/CD11b- respectively) remained unchanged. Likewise the serum concentrations of the soluble CD8 and CD4 antigen (sCD8/sCD4) as determined by sandwich enzyme immunoassays were found to be unaffected. We conclude that 40-60 years old healthy human subjects performing anaerobic training experience on average a significant decrease of circulating CD4+ T-lymphocytes, while other parameters including the activation parameters sCD8 and sCD4 remained unchanged
16 citations
TL;DR: The effectiveness of exercise conditioning regimens in patients with HIV-1 infection is reviewed and mechanisms and pathways, involving the interplay of psychological and physiological factors, through which the suppressed immune system can be enhanced are discussed.
Abstract: The human immune system is highly efficient and remarkably protective when functioning properly. Similar to other physiological systems, it functions best when the body is maintained with a balanced diet, sufficient rest and a moderately stress-free lifestyle. It can be disrupted by inappropriate drug use and extreme emotion or exertion. The functioning of normal or compromised immune systems can be enhanced by properly prescribed moderate exercise conditioning regimens in healthy people, and in some human immunodeficiency virus (HIV-1)-infected patients but not in others who unable to complete an interval training program. Regular exercise conditioning in healthy people reduces cardiovascular risk factors, increases stamina, facilitates bodyweight control, and reduces stress by engendering positive feelings of well-being. Certain types of cancer may also be suppressed by appropriate exercise conditioning. Various exercise regimens are being evaluated as adjunct treatments for medicated patients with the HIV-1 syndrome. Limited anecdotal evidence from patients suggests that moderate exercise conditioning is per se responsible for their survival well beyond expectancy. HIV-1-infected patients respond positively, both physiologically and psychologically, to moderate exercise conditioning. However, the effectiveness of any exercise treatment programme depends on its mode, frequency, intensity and duration when prescribed o complement the pathological condition of the patient. The effectiveness of exercise conditioning regimens in patients with HIV-1 infection is reviewed in this article. In addition, we discuss mechanisms and pathways, involving the interplay of psychological and physiological factors, through which the suppressed immune system can be enhanced. The immune modulators discussed are endogenous opioids, cytokines, neurotransmitters and other hormones. Exercise conditioning treatment appears to be more effective when combined with other stress management procedures.
11 citations
TL;DR: It is suggested that interval training for 12 weeks increases diastolic filling (elasticity) of the left ventricle during exercise in healthy young men, partly contributing to the increase in SV due to the training.
Abstract: To clarify the mechanism responsible for the increase in stroke volume (SV) due to training, we investigated the effects of interval training on the left ventricle using M-mode echocardiography. Six healthy male subjects volunteered to undergo 48 training sessions for 12 weeks (4 sessions• week -1) One session consisted of five periods of exercise of 3-min duration on a cycle ergometer at a power output of 100% maximal 02 uptake (Vo2max), interspersed with 2-min recovery cycling at 50% Vo2max. The echocardiograms at rest and during mild exercise (100 W) were recorded before and after the training. The interval training significantly increased Vo2max. Although there was no significant difference in SV at rest before and after the training, the training increased SV significantly during exercise. Before the training, there was a significant difference in left ventricular enddiastolic dimension (LVEDD) and left ventricular end-diastolic volume (LVEDV) at rest and during exercise. However, after the training, LVEDD and LVEDV during exercise were significantly larger than those at rest. These results suggest that interval training for 12 weeks increases diastolic filling (elasticity) of the left ventricle during exercise in healthy young men, partly contributing to the increase in SV due to the training. (Jpn. J. Phys. Fitness Sports Med. 1995, 44, 541•`546) key words: diastolic filling, echocardiography, exercise, interval training, left ventricle
TL;DR: The physiological responses of 12 competitive swimmers to a standard training workout of four sets of six 100 m freestyle repetitions per set were measured in two trials by random assignment.
Abstract: The physiological responses of 12 competitive swimmers to a standard training workout of four sets of six 100 m freestyle repetitions per set were measured in two trials. By random assignment the swimmers attempted to keep the workout constant in each trial by maintaining either a target heart rate (HR) or a target time for the 100 m efforts. The target HR or time was determined from these values measured at the anaerobic threshold (AT) during an initial determination of this exercise level. The HR after each repetition, 50 m split time, and blood lactate concentration after each set were measured throughout each workout for each swimmer. When target HR was used as the exercise criterion, the group mean (± SD) HR for the first set of six 100 m repetitions (173 ±11 beats/min) was significantly lower (p ≤ 0.05) than the group mean AT target HR (182 ± 11 beats/min), but the group mean HR for sets two, three, and four was not significantly different from the target value. Group mean lactate concentration afte...