Showing papers on "Interval training published in 1984"

Interval training and performance.

Abstract: Researchers, coaches and athletes have a variety of concepts of interval training, the only point of agreement being that interval training involves alternating bouts of exercise and recovery. The idea that interval training can be identified by a specific intensity, duration, or number of exercise bouts or by the amount or type of recovery between bouts of exercise is not valid. Rather, interval training has come to mean any type of intermittent training which, with manipulation of the number, intensity and duration of work bouts and amounts of recovery, is used to produce a particular type of stress on the body. There is general agreement that rather specific guidelines are available which determine the amount and intensity of work and the amount of rest necessary to produce specific results, and it is suggested that types of training be identified based on the specific characteristics of each particular type of training rather than placing all types of intermittent training in an all-inclusive category called ‘interval training’. Further efforts should be made to continue investigations which help determine how much, how often and for whom the various types of intermittent training are beneficial.

Fiber type changes in rat skeletal muscle after intense interval training

Abstract: Female Sprague-Dawley rats were subjected to a ten week training program to determine the influence of intense interval running on the fiber type composition of selected hindlimb muscles; soleus (S), plantaris (P), deep vastus lateralis (DVL), and superficial vastus lateralis (SVL). The muscles of one hindlimb were used for histochemical ATPase analysis to determine the distribution of fiber types and those of the contralateral hindlimb were assayed biochemically for citrate synthase activity (an aerobic marker). Training induced a significant increase in citrate synthase activity in each muscle section. The largest absolute increase occurred in the DVL and the largest relative increase occurred in the SVL. The distribution of fiber types within the S (85% slow-twitch) and SVL (100% fast-twitch) remained unchanged with training. However, significant increases in the percentage of type I (slow-twitch) fibers in both the P (2-fold) and DVL (3-fold) were observed with concomitant decreases in the type II (fast-twitch) population. In addition, training induced significant changes in the fast-twitch subtype populations of the DVL (IIB→IIA). These data suggest exercise-induced fiber type transformations occurring both within the fast-twitch population and between fast-twitch and slow-twitch fibers in certain hindlimb muscles of the rat following a high intensity interval training program.

Effects of different running programs on VO2 max, percent fat, and plasma lipids.

Abstract: This study attempted to determine the effects of interval and continuous running on factors associated with cardiovascular health. Fifty-nine untrained men and women, ages 18-32 years, were randomly assigned to one of four groups: (1) 4 mile: running continuously at 75% of maximal heart rate (approximately 500 Cal/session) (2) 2 mile: running continuously at 75% of maximal heart rate (approximately 250 Cal/session) (3) interval: running one min at 90% maximal heart rate followed by three min of walking for eight sets (approximately 500 Cal/session) (4) control: no exercise program. The training was performed three times per week for 12 weeks. Treadmill VO2 max and percent body fat by hydrostatic weighing were assessed pre- and post training. Pre and post analyses were performed on plasma for triglycerides (TG), cholesterol (Chol), and high density lipoprotein cholesterol (HDL-C). Analysis of covariance indicated that only the interval group improved more than the control in VO2 max. Percent fat decreased in all exercise groups, but no program was superior. Changes in TG, Chol, or HDL-C were not different among groups. Although men and women differed on the pretests in VO2 max, percent fat, and HDL-C, their response to the training was similar. These results indicate that interval training may benefit aerobic capacity more than continuous running in young adults who have moderately high initial fitness levels. The data also indicate that cardiovascular fitness parameters are not easily altered by short term exercise in young active men and women.

Effect of high intensity interval training on 2,3-diphosphoglycerate at rest and after maximal exercise.

Abstract: The purpose of this study was to examine the effect of intense interval training on erythrocyte 2,3-diphosphoglycerate (2,3-DPG) levels at rest and after maximal exercise. Eight normal men, mean ± SE=24.2±4.3 years, trained 4 days·week−1 for a period of 8 weeks. Each training session consisted of eight maximal 30-s rides on a cycle ergometer, with 4 min active rest between rides. Prior to and after training the subjects performed a maximal 45-s ride on an isokinetic cycle ergometer at 90 rev·min−1 and a graded leg exercise test (GLET) to exhaustion on a cycle ergometer. Blood samples were obtained from an antecubital vein before, during and after the GLET only. Training elicited significant increases in the amount of work done during the 45-s ride (P 0.05), at exhaustion (Pre=12.0±0.8; Post=11.2±0.8 Μmol·g−1 Hb;P>0.05) or during 30 min of recovery from the GLET. Additionally, acute exercise (pre-training GLET) did not effect any change in 2,3-DPG at exhaustion or during recovery from exercise compared to resting values. The higher\(\dot V_{{\text{O}}_{\text{2}} }\) max and total recovery\(\dot V_{{\text{O}}_{\text{2}} }\) values observed after training appear to be unrelated to 2,3-DPG levels. Under the present conditions, the role, if any, of 2,3-DPG in enhancing tissue oxygenation during increased metabolic demand remains obscure.

The physiological response of siberian husky dogs to exercise: effect of interval training.

Abstract: Five Siberian Husky Dogs participated in an initial study to determine their physiological response to three types of exercise. Blood samples were taken prior to, and three minutes following, a 7.5 km free run and 6 km team sled run for the determination of hemoglobin, hematocrit, red and white blood cell counts, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, lactate dehydrogenase, creatine phosphokinase and serum glutamic pyruvic transaminase. Samples were also taken following a 90s sprint run. Heart rate was taken immediately after each run by palpation of the femoral pulse. Average heart rates following the 90s, 7.5 km and 6 km runs were 190 bpm, 211 bpm and 166 bpm, respectively. Mean lactate concentrations following the 90s, 7.5 km and 6 km runs were 1.74 mMol . 1(-1), 0.70 mMol . 1(-1), and 3.06 mMol . 1(-1), respectively. Elevation of lactate dehydrogenase and creatine phosphokinase was greatest following the 6 km sled run. Three of the above dogs were then studied before and after a 12 week interval training program, while three other dogs served as controls. The animals completed a three stage, submaximal treadmill test prior to and following the program. Pre and post blood samples were taken, and rectal temperature and heart rate were recorded continuously throughout the test. An analysis of variance was used to examine the significance of differences between and within groups. Although the response of heart rate, lactate, temperature and serum enzymes to submaximal exercise did not change with training significant differences between groups suggested that a more prolonged program may have resulted in such adaptations.

Influence of diet and training on the metabolic responses to maximal exercise in man

Abstract: The aim of the studies reported in this thesis was to use an all-out cycle ergometer test (the Anaerobic Work Test - AWTl as a laboratory testl of fatigue during truly maximal dynamic exercise in the attempt to determine il how the body copes with the challenge of maximal exercise and iil what factors govern the ability of an individual to perform maximal exercise. Whilst differences in musculature accounted for a major portion of the variance in the ability to perform maximal cycle ergometer exercise, much of the remaining variance may be attributable to differences in training status. The differences in the ability to generate power over the AWT observed between male and female subjects could be principally attributed to differences in body size and musculature. Although there was little'relationship between functional capacity and the aerobic capacity of the individual, an enhanced ability to generate power could also be associated with a high aerobic capacity. Maximal cycle ergometer training was found to result in marked improvements in the ability to perform maximal exercise, whilst endurance training neither impaired nor enhanced performance. The ability to perform a second bout of maximal exercise was found to be dependent apon the duration of recovery between bouts, although not influenced by alterations in either carbohydrate-status or blood acid-base status. Attempts to perform repeated 65 bouts of maximal exercise with either 30 or 60s recovery resulted in pronounced fatigue-induced decrements in performance and marked increases in blood lactate. Peak plasma adrenaline, plasma noradrenaline, blood lactate and blood glucose concentrations following 6s of maximal exercise averaged 1.7 nmolll, 3.30 nmolll, 2.68 mmolll and 4.63 mmolll respectively whilst the corresponding values after 30s averaged 4.31 nmolll, 12.91 nmolll, 11.93 mmolll and 5.35 nmol/l./on the basis of the changes in muscle metabolites over the AWT, the greatest power outputs generated 6ver the initial seconds of maximal exercise were associated with the greatest rates of ATP turnover from non-oxidative metabolism (7.7-12.4 mmollkg dm/sl and was the p=d,uct of maximal rates of phosphagenolysis and glycolysis. The rate of ATP \, turnover appeared to decrease in association with a reduction in power output as exercise preceded, primarily as a result of a reduction in the rate of CP utilisation. ATP turnover over 30s of maximal exercise ranged from 5.15-7.59 mmol/kg dm/s. The metabolic condition following 30s of maximal elercise wa~ comparable to that observed following a wide variety of exhaustive high-intensity exercise tasks: muscle ATP, CP and lactate concentrations averaged 13.7, 28.8 and 89.3 mmol/kg dm respectively. Whilst interval training resulted in an enhanced ability to perform single and repeated bouts of maximal exercise, the imporvements in performance could not be attributed to a greater provision of energy from non-oxidative metabolism. The storage and utilisation of CP and ATP, and the accumulation of lactate, were unaltered; however, glycogen storage and mobilisation of glucosyl units increased by 341 and 631 respectively resulting in a greater accumulation of hexose monophosphates. A metabolic basis of muscular fatigue during maximal cycle ergometer exercise, and the influence of training on these processes, was then discussed. 'The accumulation of hydrogen ions within the working muscle was proposed as a common factor that would influence both the rate at which ATP was resynthesised and utilised.

Fiber type changes in rat skeletal muscle after intense interval training

Abstract: Summary. Female Sprague-Dawley rats were subjected to a ten week training program to determine the influence of intense interval running on the fiber type composition of selected hindlimb muscles; soleus (S), plantaris (P), deep vastus lateralis (DVL), and superficial vastus lateralis (SVL). The muscles of one hindlimb were used for histochemical ATPase analysis to determine the distribution of fiber types and those of the contralateral hindlimb were assayed biochemically for citrate synthase activity (an aerobic marker). Training induced a significant increase in citrate synthase activity in each muscle section. The largest absolute increase occurred in the DVL and the largest relative increase occurred in the SVL. The distribution of fiber types within the S (85% slow-twitch) and SVL (100% fasttwitch) remained unchanged with training. However, significant increases in the percentage of type I (slow-twitch) fibers in both the P (2-fold) and DVL (3-fold) were observed with concomitant decreases in the type II (fast-twitch) population. In addition, training induced significant changes in the fast-twitch subtype populations of the DVL (IIB IIA). These data suggest exercise-induced fiber type transformations occurring both within the fast-twitch population and between fast-twitch and slow-twitch fibers in certain hindlimb muscles of the rat following a high intensity interval training program.