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Training the Aerobic Capacity of Distance Runners: A Break From Tradition
Abstract
AEROBIC CAPACITY IS DETERMINED BY 3 FACTORS: (A) MAXIMAL OXYGEN UPTAKE, (B) LACTATE THRESHOLD (LT), AND (C) RUNNING ECONOMY (RE), AND EACH ONE SHOULD BE TARGETED TO OPTIMIZE DEVELOPMENT. IT APPEARS THAT V̇o2MAX AND LT CAN BE ADAPTED SIMULTANEOUSLY AND MAY BE BEST TRAINED THROUGH HIGH-INTENSITY INTERVALS. RE MAY BE BEST DEVELOPED THROUGH STRENGTH, POWER, AND PLYOMETRICS TRAINING. FINALLY, REPLACING ONE-THIRD OF THE TOTAL ENDURANCE TRAINING TIME WITH GYM-BASED TRAINING APPEARS MOST BENEFICIAL.
... Enduro MTB racers are subject to long bouts of moderate to high intensity exercise during race days with little rest between bouts, making economy a key factor in race success. Multiple review articles (Turner, 2009;2011) addressed the efficacy of different strength and conditioning strategies for improving rate of force production and power, and therefore economy in endurance athletes. These recommendations emphasize separate strength and power sessions with 3-5 sets of 3-5 repetitions at high loads (at least 85% 1 repetition maximum [1RM]). ...
The mountain bike (MTB) discipline known as enduro involves competitors racing off-road bicycles on several timed, and primarily downhill, stages over several days with untimed "liaisons" in which competitors must commute to the next timed section within a specified time. Unlike the cross country MTB discipline in which climbs are often completed above 90% of their maximal oxygen consumption (VO 2 max) with no respite before descents (Macdermid, 2012) the uphill sections in enduro racing are completed below 90% VO 2 max and competitors have short rest periods between completing these climbs and starting the timed downhill stages. These stages also differ significantly from downhill MTB racing in that enduro stages tend to be longer and have fewer man-made features. However, the timed stages in enduro, like downhill, are raced primarily out of saddle and involve significant contribution from both lower and upper body musculature (Burr, 2012). Enduro MTB races typically take place in mountainous regions during the summer, meaning that competitors must consider environmental factors such as altitude and heat when preparing for these races. The purpose of this article is to address and present strategies for dealing with environmental factors that affect performance during enduro MTB events.
... Subsequently, a higher aerobic capacity would help to support recovery during this type of activity. 50,51,52 Lemmink and Visscher 30 analysed the role of energy systems in two intermittent field tests in female field hockey players. The energetics of two field tests were examined in 21 players. ...
Data collection and interpretation plays a major role in strength and conditioning practice. The most common situation this applies to is the measurement of physical capabilities, and the subsequent analysis of testing scores. However, the importance of data handling skills and statistical analysis is not always adequately emphasised during applied strength and conditioning education, which may result is some individuals lacking confidence in this area. In particular, it is important that the practitioner understands the difference between an observed score and the true score, and how error in measurement reduces our ability to detect real change in testing scores. The following article aims to provide an applied step by step guide to calculating typical error, determining reliability, and establishing the minimum difference to be considered real.
TRAINING ONE'S METABOLISM FOR MAXIMUM EFFICIENCY IS A CRITICAL PHYSICAL COMPONENT FOR MANY COMPETITIVE ACTIVITIES. THE TRAINING NEEDS TO STRESS THE PROPER ENERGY SYSTEM IN THE APPROPRIATE AMOUNT BASED ON THE WORK-TO-REST RATIO SPECIFIC TO THE GIVEN ACTIVITY. BECAUSE OF THE DIFFERENT INTENSITIES OF THE COMPONENT SPORTS OF MIXED MARTIAL ARTS (MMA), AN MMA MATCH CAN REQUIRE EACH OF THE 3 ENERGY SYSTEMS TO BE USED AT VARIOUS TIMES IN EACH ROUND. THE FOLLOWING IS AN EXAMPLE OF A 12-WEEK METABOLIC CONDITIONING PROGRAM THAT PROGRESSIVELY TRAINS THE PHOSPHAGEN, GLYCOLYTIC, AND OXIDATIVE ENERGY SYSTEMS FOR AN MMA ATHLETE.
(C) 2014 by the National Strength & Conditioning Association
Spatially indirect radiative recombinations (type II) have been studied in InAlAs–InP heterostructures grown by gas source molecular beam epitaxy with emphasis on the direct (InAlAs grown on InP) or inverse (InP on InAlAs) interface composition profile. Based on the results of their injection-dependent energy, lifetime and polarization, a new transition scheme is proposed: type II transitions have a low injection limit between 1.27 and 1.28 eV, a long lifetime (τ>1 μs) and strongly shift towards higher energy when increasing the injection. The type II recombination is polarized, the direction of maximum intensity being correlated with the expected interface structure. Lower energy transitions (E ⩽ 1.2 eV) indicate the presence of a well transition material at the interface: they should be better labeled as mixed type I–II. Previously published results are also reconsidered and seem to fit well within this model. © 1998 American Institute of Physics.
This study investigated the effects of a high volume 5-wk weight training program and different exercise/rest intervals on measures of power, high intensity exercise endurance (HIEE), and maximum strength. Subjects, 33 weight trained men (M age 20.4+/-3.5 yrs), were divided into 3 equal groups. The groups used the same exercises and set-and-repetition scheme. Rest intervals were 3 min for Gp 1, 1.5 min for Gp 2, and 0.5 min for Gp 3. Pre/post changes were analyzed using G x T ANOVA. Peak power, average peak power, and average total work, as measured during 15 five-sec cycle max-efforts rides and the 1-RM squat, increased significantly (N = 33, p < 0.05). The vertical jump and vertical jump power index did not show a statistically significant change. The 1-RM squat increased significantly more in Gp 1 (7%) than in Gp 3 (2%). Data suggest that, except for maximum strength, adaptations, to short-term, high-volume training may not be dependent on the length of rest intervals.
(C) 1995 National Strength and Conditioning Association
EFFICIENT STRETCH-SHORTENING CYCLE (SSC) MECHANICS RESULT IN ENERGY CONSERVATION AND ENHANCED PROPULSIVE FORCES. BASED ON THE CURRENT REVIEW OF RESEARCH, ELASTIC ENERGY THROUGH TENDON RECOIL AND AN INCREASE IN ACTIVE STATE BECAUSE OF AN INCREASE IN THE WORKING RANGE SEEM THE MOST PLAUSIBLE EXPLANATION FOR THE SSC MECHANISM. USING THE RESEARCH PRESENTED, THE SSC MECHANISM MAY BE BEST DEVELOPED USING THE PLYOMETRICS PYRAMID ENSURING THAT THE ATHLETE IS TECHNICALLY COMPETENT AT EACH STAGE BEFORE PROGRESSING IN INTENSITY AND COMPLEXITY. STRENGTH TRAINING AND SSC TRAINING SHOULD BE PERFORMED CONCURRENTLY. SSC DRILLS SHOULD BE BASED ON STRENGTH CAPACITIES AND SPORT-SPECIFIC VARIABLES.
The oxygen cost and energy expenditure of submaximal treadmill running was evaluated in 9 male distance runners. The oxygen consumption--running speed relationship was highly significant (r = .917) and linear over the entire aerobic range. The caloric cost of 0.97 Kcal/kg/k was in close agreement with values found in the literature and was independent of running speed. The caloric cost per unit distance and time increased with acceleration in running speed. The slope of the regression line of oxygen consumption on running speed appear to measure a different component of efficiency than the fractional utilization coefficient of aerobic capacity. There is apparently a wide variation in the oxygen cost of running in trained runners.
Our purpose was to examine the effects of sprint interval training on muscle glycolytic and oxidative enzyme activity and exercise performance. Twelve healthy men (22 +/- 2 yr of age) underwent intense interval training on a cycle ergometer for 7 wk. Training consisted of 30-s maximum sprint efforts (Wingate protocol) interspersed by 2-4 min of recovery, performed three times per week. The program began with four intervals with 4 min of recovery per session in week 1 and progressed to 10 intervals with 2.5 min of recovery per session by week 7. Peak power output and total work over repeated maximal 30-s efforts and maximal oxygen consumption (VO2 max) were measured before and after the training program. Needle biopsies were taken from vastus lateralis of nine subjects before and after the program and assayed for the maximal activity of hexokinase, total glycogen phosphorylase, phosphofructokinase, lactate dehydrogenase, citrate synthase, succinate dehydrogenase, malate dehydrogenase, and 3-hydroxyacyl-CoA dehydrogenase. The training program resulted in significant increases in peak power output, total work over 30 s, and VO2 max. Maximal enzyme activity of hexokinase, phosphofructokinase, citrate synthase, succinate dehydrogenase, and malate dehydrogenase was also significantly (P < 0.05) higher after training. It was concluded that relatively brief but intense sprint training can result in an increase in both glycolytic and oxidative enzyme activity, maximum short-term power output, and VO2 max.
To investigate the effects of simultaneous explosive-strength and endurance training on physical performance characteristics, 10 experimental (E) and 8 control (C) endurance athletes trained for 9 wk. The total training volume was kept the same in both groups, but 32% of training in E and 3% in C was replaced by explosive-type strength training. A 5-km time trial (5K), running economy (RE), maximal 20-m speed (V20 m), and 5-jump (5J) tests were measured on a track. Maximal anaerobic (MART) and aerobic treadmill running tests were used to determine maximal velocity in the MART (VMART) and maximal oxygen uptake (VO2 max). The 5K time, RE, and VMART improved (P < 0.05) in E, but no changes were observed in C. V20 m and 5J increased in E (P < 0.01) and decreased in C (P < 0.05). VO2 max increased in C (P < 0.05), but no changes were observed in E. In the pooled data, the changes in the 5K velocity during 9 wk of training correlated (P < 0.05) with the changes in RE [O2 uptake (r = -0.54)] and VMART (r = 0.55). In conclusion, the present simultaneous explosive-strength and endurance training improved the 5K time in well-trained endurance athletes without changes in their VO2 max. This improvement was due to improved neuromuscular characteristics that were transferred into improved VMART and running economy.
The maximal rate of rise in muscle force [rate of force development (RFD)] has important functional consequences as it determines the force that can be generated in the early phase of muscle contraction (0-200 ms). The present study examined the effect of resistance training on contractile RFD and efferent motor outflow ("neural drive") during maximal muscle contraction. Contractile RFD (slope of force-time curve), impulse (time-integrated force), electromyography (EMG) signal amplitude (mean average voltage), and rate of EMG rise (slope of EMG-time curve) were determined (1-kHz sampling rate) during maximal isometric muscle contraction (quadriceps femoris) in 15 male subjects before and after 14 wk of heavy-resistance strength training (38 sessions). Maximal isometric muscle strength [maximal voluntary contraction (MVC)] increased from 291.1 +/- 9.8 to 339.0 +/- 10.2 N. m after training. Contractile RFD determined within time intervals of 30, 50, 100, and 200 ms relative to onset of contraction increased from 1,601 +/- 117 to 2,020 +/- 119 (P < 0.05), 1,802 +/- 121 to 2,201 +/- 106 (P < 0.01), 1,543 +/- 83 to 1,806 +/- 69 (P < 0.01), and 1,141 +/- 45 to 1,363 +/- 44 N. m. s(-1) (P < 0.01), respectively. Corresponding increases were observed in contractile impulse (P < 0.01-0.05). When normalized relative to MVC, contractile RFD increased 15% after training (at zero to one-sixth MVC; P < 0.05). Furthermore, muscle EMG increased (P < 0.01-0.05) 22-143% (mean average voltage) and 41-106% (rate of EMG rise) in the early contraction phase (0-200 ms). In conclusion, increases in explosive muscle strength (contractile RFD and impulse) were observed after heavy-resistance strength training. These findings could be explained by an enhanced neural drive, as evidenced by marked increases in EMG signal amplitude and rate of EMG rise in the early phase of muscle contraction.
Maximal strength-training with an emphasis on maximal mobilization during cross-country skiing increases exercise economy when double-poling. The aim of this experiment was to investigate whether the mechanism of this increase is a change in the force-velocity relationship and the mechanical power output. A group of 19 cross-country skiers having an average peak oxygen uptake of 255 ml x kg(-0.67) body mass x min(-1) or 61 ml x kg(-1) x min(-1) were randomly assigned to either a high resistance-training group (n=10) or a control group (n=9). Upper body endurance was tested on a ski ergometer. The high-resistance-training group trained for 15 min on three occasions a week for 9 weeks. Training consisted of three series of five repetitions using 85% of one repetition maximum (1RM), with emphasis on high velocity in the concentric part of the movement. Upper body exercise economy, 1RM and time to exhaustion increased significantly in the high resistance-training group, but was unchanged in the control group. Peak power and the velocities for a given load increased significantly, except for the two lowest loads. We conclude that the increased exercise economy after a period of upper body high resistance-training can be partly explained by a specific change in the force-velocity relationship and the mechanical power output.
The purpose of this investigation was to characterize the effects of marathon training on single muscle fiber contractile function in a group of recreational runners. Muscle biopsies were obtained from the gastrocnemius muscle of seven individuals (22 +/- 1 yr, 177 +/- 3 cm, and 68 +/- 2 kg) before, after 13 wk of run training, and after 3 wk of taper. Slow-twitch myosin heavy chain [(MHC) I] and fast-twitch (MHC IIa) muscle fibers were analyzed for size, strength (P(o)), speed (V(o)), and power. The run training program led to the successful completion of a marathon (range 3 h 56 min to 5 h 35 min). Oxygen uptake during submaximal running and citrate synthase activity were improved (P < 0.05) with the training program. Muscle fiber size declined (P < 0.05) by approximately 20% in both fiber types after training. P(o) was maintained in both fiber types with training and increased (P < 0.05) by 18% in the MHC IIa fibers after taper. This resulted in >60% increase (P < 0.05) in force per cross-sectional area in both fiber types. Fiber V(o) increased (P < 0.05) by 28% in MHC I fibers with training and was unchanged in MHC IIa fibers. Peak power increased (P < 0.05) in MHC I and IIa fibers after training with a further increase (P < 0.05) in MHC IIa fiber power after taper. These data show that marathon training decreased slow-twitch and fast-twitch muscle fiber size but that it maintained or improved the functional profile of these fibers. A taper period before the marathon further improved the functional profile of the muscle, which was targeted to the fast-twitch muscle fibers.
The aim of this study was to compare the effects of two high-intensity interval training (HIT) programmes on maximal oxygen uptake (.VO(2max)), the lactate threshold (LT) and 3000 m running performance in moderately trained male runners. .VO(2max), the running speed associated with .VO(2max) (V.VO(2max)), the time for which V.VO(2max) can be maintained (T(max)), the running speed at LT (v(LT)) and 3000 m running time (3000 mTT) were determined before and following three different training programmes performed for 10 weeks. Following the pre-test, 17 moderately trained male runners (V O(2max)=51.6+/-2.7ml kg(-1)min(-1)) were divided into training groups based on their 3000 mTT (Group 1, G(1), N=6, 8 x 60% of T(max) at V.VO(2max), 1:1 work:recovery ratio; Group 2, G(2), N=6, 12 x 30s at 130% V.VO(2max), 4.5 min recovery; control group, G(CON), N=5, 60 min at 75% V.VO(2max)). G(1) and G(2) performed two HIT sessions and two 60 min recovery run sessions (75% V.VO(2max)) each week. Control subjects performed four 60 min recovery run sessions (75% V.VO(2max)) each week. In G(1), significant improvements (p<0.05) following HIT were found in .VO(2max) (+9.1%), V.VO(2max) (+6.4%), T(max) (5%), v(LT) (+11.7%) and 3000 mTT (-7.3%). In G(2), significant improvements (p<0.05) following HIT were found in .VO(2max) (+6.2%), V.VO(2max)(+7.8%), T(max) (+32%) and 3000 mTT (-3.4%), but not in v(LT) (+4.7%; p=0.07). No significant changes in these variables were found in G(CON). The present study has shown that 3000 m running performance, .VO(2max), V.VO(2max), T(max) and v(LT) can be significantly enhanced using different HIT programmes in moderately trained runners, but that changes in performance and physiological variables may be more profound using prolonged HIT at intensities of V.VO(2max) with interval durations of 60% T(max).
Exercise training reduces the symptoms of chronic heart failure. Which exercise intensity yields maximal beneficial adaptations is controversial. Furthermore, the incidence of chronic heart failure increases with advanced age; it has been reported that 88% and 49% of patients with a first diagnosis of chronic heart failure are >65 and >80 years old, respectively. Despite this, most previous studies have excluded patients with an age >70 years. Our objective was to compare training programs with moderate versus high exercise intensity with regard to variables associated with cardiovascular function and prognosis in patients with postinfarction heart failure.
Twenty-seven patients with stable postinfarction heart failure who were undergoing optimal medical treatment, including beta-blockers and angiotensin-converting enzyme inhibitors (aged 75.5+/-11.1 years; left ventricular [LV] ejection fraction 29%; VO2peak 13 mL x kg(-1) x min(-1)) were randomized to either moderate continuous training (70% of highest measured heart rate, ie, peak heart rate) or aerobic interval training (95% of peak heart rate) 3 times per week for 12 weeks or to a control group that received standard advice regarding physical activity. VO2peak increased more with aerobic interval training than moderate continuous training (46% versus 14%, P<0.001) and was associated with reverse LV remodeling. LV end-diastolic and end-systolic volumes declined with aerobic interval training only, by 18% and 25%, respectively; LV ejection fraction increased 35%, and pro-brain natriuretic peptide decreased 40%. Improvement in brachial artery flow-mediated dilation (endothelial function) was greater with aerobic interval training, and mitochondrial function in lateral vastus muscle increased with aerobic interval training only. The MacNew global score for quality of life in cardiovascular disease increased in both exercise groups. No changes occurred in the control group.
Exercise intensity was an important factor for reversing LV remodeling and improving aerobic capacity, endothelial function, and quality of life in patients with postinfarction heart failure. These findings may have important implications for exercise training in rehabilitation programs and future studies.
summary: Endurance can be defined as the ability to maintain or to repeat a given force or power output. The sport performance-endurance relationship is a multi-factorial concept. However, evidence indicates that maximum strength is a major component. Conceptually, endurance is a continuum. The literature indicates that (a) maximum strength is moderately to strongly related to endurance capabilities and associated factors, a relationship that is likely stronger for high intensity exercise endurance (HIEE) activities than for low intensity exercise endurance (LIEE); (b) strength training can increase both HIEE and LIEE, the effect being greater for HIEE; (c) the volume of strength training plays a role in endurance adaptation; and (d) mechanical specificity and training program variables also play a role in the degree of adaptation. (C) 2006 National Strength and Conditioning Association
Recombination processes in antimonide-based materials for thermophotovoltaic (TPV) devices have been investigated using a radio-frequency (rf) photoreflectance technique, in which a Nd–YAG pulsed laser is used to excite excess carriers, and the short-pulse response and photoconductivity decay are monitored with an inductively coupled noncontacting rf probe. Both lattice-matched AlGaAsSb and GaSb have been used to double cap InGaAsSb active layers to evaluate bulk lifetime and surface recombination velocity with different active layer thicknesses. With an active layer doping of 2×1017 cm−3, effective bulk lifetimes of 95 ns and surface recombination velocities of 1900 cm/s have been obtained. As the laser intensity is increased the lifetime decreases, which is attributed to radiative recombination under these high-level injection conditions. Similar measurements have been taken on both TPV device structures and starting substrate materials for comparison purposes. © 1999 American Institute of Physics.
summary: Endurance can be defined as the ability to maintain or to repeat a given force or power output. The sport performance-endurance relationship is a multi-factorial concept. However, evidence indicates that maximum strength is a major component. Conceptually, endurance is a continuum. The literature indicates that (a) maximum strength is moderately to strongly related to endurance capabilities and associated factors, a relationship that is likely stronger for high intensity exercise endurance (HIEE) activities than for low intensity exercise endurance (LIEE); (b) strength training can increase both HIEE and LIEE, the effect being greater for HIEE; (c) the volume of strength training plays a role in endurance adaptation; and (d) mechanical specificity and training program variables also play a role in the degree of adaptation.
(C) 2006 National Strength and Conditioning Association
The effects of a 24-weeks' progressive training of neuromuscular performance capacity on maximal strength and on hormone balance were investigated periodically in 21 male subjects during the course of the training and during a subsequent detraining period of 12 weeks. Great increases in maximal strength were noted during the first 20 weeks, followed by a plateau phase during the last 4 weeks of training. Testosterone/cortisol ratio increased during training. During the last 4 weeks of training changes in maximal strength correlated with the changes in testosterone/cortisol (P<0.01) and testosterone/SHBG (P<0.05) ratios. During detraining, correlative decreases were found between maximal strength and testosterone/cortisol ratio (P<0.05) as well as between the maximal strength and testosterone/SHBG ratio (P<0.05). No statistically significant changes were observed in the levels of serum estradiol, lutropin (LH), follitropin (FSH), prolactin, and somatotropin. The results suggest the importance of the balance between androgenic-anabolic activity and catabolizing effects of glucocorticoids during the course of vigorous strength training.
A systems model, providing an estimation of fatigue and fitness levels was applied to a 1-year training period of six elite weight-lifters. The model parameters were individually determined by fitting the predicted performance (calculated as the difference between fitness and fatigue) to the actual one. The purpose of this study was to validate the systems model by comparing the estimated levels of fatigue and fitness with biological parameters external to the model calculation. The predicted and the actual performances were significantly correlated in each subject. The calculated fitness and fatigue levels were related to serum testosterone concentration, testosterone: cortisol and testosterone: sex hormone binding globulin ratios. The best results were obtained by the comparison between fitness and testosterone levels, which varied in parallel in each subject. In two subjects this correlation was significant (r = 0.91, P less than 0.05, and r = 0.92, P less than 0.01). The fitness changes calculated in each subject between the 15th and the 51st weeks of training were significantly correlated with the changes in serum testosterone concentration measured in the same period (r = 0.99, P less than 0.001). For the whole group testosterone and fitness variations were also significantly intercorrelated (r = 0.73, P less than 0.001). Correlations, less homogeneous and less significant, were calculated also for other hormones and ratios. These results suggest that (1) the relationships between training and performance can be described by the systems model, (2) the estimated index of fitness has a physiological meaning. The fatigue index remains to be clarified.
Increases in muscular strength among initially untrained subjects are relatively easily attained taking place during the earlier weeks of strength training mainly due to neural adaptations with a gradually increasing contribution of hypertrophic factors as the training proceeds. Muscular strength development in strength athletes is much more limited and special attention should be given to high training loading intensity and to individual training programming. The magnitudes and the time courses of the neuromuscular adaptations in strength athletes may therefore differ from those among initially untrained subjects but the actual mechanisms of strength increase may be basically the same. The initial status of the athletes makes the process more complicated to follow and more difficult to substantiate. In strength athletes with a long training background and with a high training volume, the role of endogenous hormone balance may have increasing importance for strength development. During the most stressful training weeks of prolonged strength training the level of biologically active unbound testosterone as well as the balance between the androgenic-anabolic activity and the catabolizing effect of glucocorticoids may be of great importance for the trainability of muscular strength. These observations together with the findings about the specific effects of heavy resistance strength and power training on the neuromuscular performance may also have some implications for the more accurate determination of the trainability status of an individual athlete at a given time in order to optimize the training process.
Neuromuscular and hormonal adaptations to prolonged strength training were investigated in nine elite weight lifters. The average increases occurred over the 2-yr follow-up period in the maximal neural activation (integrated electromyogram, IEMG; 4.2%, P = NS), maximal isometric leg-extension force (4.9%, P = NS), averaged concentric power index (4.1%, P = NS), total weight-lifting result (2.8%, P less than 0.05), and total mean fiber area (5.9%, P = NS) of the vastus lateralis muscle, respectively. The training period resulted in increases in the concentrations of serum testosterone from 19.8 +/- 5.3 to 25.1 +/- 5.2 nmol/l (P less than 0.05), luteinizing hormone (LH) from 8.6 +/- 0.8 to 9.1 +/- 0.8 U/l (P less than 0.05), follicle-stimulating hormone (FSH) from 4.2 +/- 2.0 to 5.3 +/- 2.3 U/l (P less than 0.01), and testosterone-to-serum sex hormone-binding globulin (SHBG) ratio (P less than 0.05). The annual mean value of the second follow-up year for the serum testosterone-to-SHBG ratio correlated significantly (r = 0.84, P less than 0.01) with the individual changes during the 2nd yr in the averaged concentric power. The present results suggest that prolonged intensive strength training in elite athletes may influence the pituitary and possibly hypothalamic levels, leading to increased serum levels of testosterone. This may create more optimal conditions to utilize more intensive training leading to increased strength development.
This review has grouped many studies on different populations with different protocols to show the interactive effects of intensity, frequency and duration of training as well as the effects of initial fitness levels and programme length on cardiorespiratory fitness as reflected by aerobic power (V̇O2max). Within each level of exercise duration, frequency, programme length or initial fitness level, the greatest improvements in aerobic power occur when the greatest challenge to aerobic power occurs i.e., when intensity is from 90 to 100% of V̇O2max. The pattern of improvement where different intensities are compared with different durations suggests that when exercise exceeds 35 minutes, a lower intensity of training results in the same effect as those achieved at higher intensities for shorter durations. Frequencies of as low as 2 per week can result in improvements in less fit subjects but when aerobic power exceeds 50 ml/kg/min, exercise frequency of at least 3 times per week is required. As the levels of initial fitness improve, the change in aerobic power decreases regardless of the intensity, frequency or duration of exercise.
Although these pooled data suggest that maximal gains in aerobic power are elicited with intensities between 90 to 100% V̇O2 max, 4 times per week with exercise durations of 35 to 45 minutes, it is important to note that lower intensities still produce effective changes and reduce the risks of injury in non-athletic groups.
Swedish military conscripts participated in 3 separate programs of interval training (principal activity - running): Group I (N = 20): 15 sec exercise + 15 sec rest, 3 days/week for 2 months. Group II (N = 9): 3 min exercise + 3 min rest, 3 days/week for 2 months, Group III (N = 8): 1 month no formal program, then 3 min exercise + 3 min rest, 5 days/week for 1 month. For each group, total time for exercise of high intensity = 15 min per session. Testing was performed on a cycle ergometer at induction, after 1 month, and after 2 months. Significant increases in max[latin capital V with dot above]o2 were observed for all groups (mean increase approximately 20%). Maximal oxygen uptake increased from 3.1, 2.9 and 3.2 to 3.6, 3.6 and 3.9 ] x min-1 for groups I, II and III, respectively. Concomitant reductions occurred in HR and perceived exertion at submaximal exercise (150 W). Individual improvement was inversely related to initial fitness, the lower the level at induction the greater the increase relative to this value. Subgroups tested 8 months after cessation of training (at discharge) had regressed to levels not different from those at induction. Conclusions: 1) physical fitness in this age group can be markedly and rapidly improved by interval training, 2) marked improvement in aerobic power capacity can be brought about by an impressively short time investment, 3) the training regimen based on 3-min periods was more effective than 15-sec periods, and 4) military life in this situation (communications regiment) was not sufficient to maintain a high level of fitness when the physical conditioning program was discontinued. (C)1973The American College of Sports Medicine
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.
The purpose of the study was to examine the influence of passive tendon work on the gross mechanical efficiency of human whole body movement. Seven male subjects participated in the study. They performed repetitive jumps (like skipping) of three different intensities. Metabolic costs and work rates were recorded to obtain mechanical efficiencies. Net joint moments were calculated from film recordings using inverse dynamics. A general stress-strain relationship for tendons was modelled using a quadratic function, including Youngs elastic modulus of tendon tissue and tendon dimensions. Instantaneous tendon moment arms for the largest leg extensor muscles (m. triceps surae and m. quadriceps femoris) were calculated using joint angle-moment arm transfer functions obtained from the literature (cadaver studies) and the tendon work was calculated from the net joint moments. Gross efficiency values of 0.65-0.69 and efficiency values of 0.77-0.80 at the approximate level of the muscle-tendon complexes were observed. The tendons performed 52-60% of the total work. The enhancement of the muscle-tendon efficiency over the maximal theoretical efficiency of the contractile machinery (0.30) could exclusively be explained by the contribution of the tendon work. A clear negative relationship between repetitive jumping with high mechanical efficiency and running economy at 12 km h-1 was found. Using model calculations the gross efficiency and the muscle-tendon efficiency were shown to be sensitive to tendon Youngs modulus, dimensions and moment arms. The efficiencies were most sensitive to changes in the tendon moment arms. A 10% decrease in tendon moment arms resulted in a 13% increase in the gross efficiency. Optimization or minimisation of the mechanical efficiency by changing the tendon variables 5% was followed by changes in mechanical efficiency of +14% and -10%, respectively.
This study examined the effect of resistance training on exercise-induced contrast shift in magnetic resonance (MR) images. It was hypothesized that a given load could be lifted after training with less muscle showing contrast shift, thereby suggesting less muscle was used to perform the exercise. Nine males trained the left quadriceps femoris (QF) muscle 2 days/wk for 9 wk using 3-6 sets of 12 knee extensions each day. The right QF served as a "control." Exercise-induced contrast shifts in MR images evoked by each of three bouts of exercise (5 sets of 10 knee extensions with a load equal to 50, 75, and 100% of the maximum pretraining load that could be lifted for 5 sets of 10 repetitions) were quantified pre- and posttraining. MR image contrast shift was quantified by determining QF cross-sectional area (CSA) showing increased spin-spin relaxation time. One repetition maximum increased 14% in the left trained QF and 7% in the right untrained QF. Left QF CSA increased 5%, with no change in right QF CSA. Left QF CSA showing contrast shift was less after each bout of the exercise test posttraining. This was also true, to a lesser extent, for the right QF at the higher two loads. The results suggest that short-term resistance training reduces MR image contrast shift evoked by a given effort, thereby reflecting the use of less muscle to lift the load. Because this response was evident in both trained and contralateral untrained muscle, neural factors are suggested to be responsible.(ABSTRACT TRUNCATED AT 250 WORDS)
Sex differences in running economy (gross oxygen cost of running, CR), maximal oxygen uptake (VO2max), anaerobic threshold (Than), percentage utilization of aerobic power (% VO2max), and Than during running were investigated. There were six men and six women aged 20–30 years with a performance time of 2 h 40 min over the marathon distance. The VO2max, Than, and CR were measured during controlled running on a treadmill at 1° and 3° gradient. From each subject's recorded time of running in the marathon, the average speed (v
M) was calculated and maintained during the treadmill running for 11 min. The VO2 max was inversely related to body mass (m
b), there were no sex differences, and the mean values of the reduced exponent were 0.65 for women and 0.81 for men. These results indicate that for running the unit ml·kg−0.75·min−1 is convenient when comparing individuals with different m
b. The VO2max was about 10% (23 ml·kg−0.75·min−1) higher in the men than in the women. The women had on the average 10–12 ml·kg−0.75·min−1 lower VO2 than the men when running at comparable velocities. Disregarding sex, the mean value of CR was 0.211 (SEM 0.005) ml·kg−1·m−1 (resting included), and was independent of treadmill speed. No sex differences in Than expressed as % VO2max or percentage maximal heart rate were found, but Than expressed as VO2 in ml·kg−0.75·min−1 was significantly higher in the men compared to the women. The percentage utilization of f
emax and concentration of blood lactate at v
M was higher for the female runners. The women ran 2 days more each week than the men over the first 4 months during the half year preceding the marathon race. It was concluded that the higher VO2max and Than in the men was compensated for by more running, superior CR, and a higher exercise intensity during the race in the performance-matched female marathon runners.
To compare the effects of three types of intensive run training on running economy (RE) during exhaustive running and to establish possible relationships with changes in ventilatory function and/or muscle fiber type distribution.
Thirty-six male recreational runners were divided into three groups and assigned to either exhaustive distance training (DT), long-interval training (LIT), or short-interval training (SIT) three times 20-30 minxwk(-1) for 6 wk. VO(2 max) and RE were measured during treadmill running before and after training. Muscle fiber type distribution of the vastus lateralis muscle was established from biopsy material.
VO(2max) (Lxmin(-1) increased by 5.9% (P < 0.0001), 6.0% (P < 0.0001), and 3.6% (P < 0.01) in DT, LIT, and SIT, respectively, and running speed at VO(2max) by 9% (P < 0.0001), 10% (P < 0.0001), and 4% (P < 0.05), respectively. Time-to-exhaustion at 87% of pretraining VO(2max) (mean 3.83) mxs(-1) increased by 94% in DT (P < 0.0001), 67% in LIT (P < 0.0001). Running economy improved by 3.1% in DT (P < 0.05), 3.0% in LIT (P < 0.01), and 0.9% SIT (NS): pulmonary ventilation (VE) was on average 11 Lxmin(-1) lower following training (P < 0.0001). The individual decrements in VE correlated with improvements in RE (r = 0.77; P < 0.0001) and may account for 25-70% of the decrease in aerobic demand. Muscle fiber composition, and respiratory exchange ratio, stride length, and stride frequency during running were unaltered with training.
Recreational runners can improve RE and aerobic run performance by exchanging parts of their conventional aerobic distance training with intensive distance or long-interval running, whereas short-interval running is less efficient. The improvement in RE may relate to reduced ventilatory demands. Muscle fiber type distribution was unaltered with training and showed no associations with RE.
The aim of the present study was to study the effects of aerobic training on performance during soccer match and soccer specific tests.
Nineteen male elite junior soccer players, age 18.1 +/- 0.8 yr, randomly assigned to the training group (N = 9) and the control group (N = 10) participated in the study. The specific aerobic training consisted of interval training, four times 4 min at 90-95% of maximal heart rate, with a 3-min jog in between, twice per week for 8 wk. Players were monitored by video during two matches, one before and one after training.
In the training group: a) maximal oxygen uptake (VO2max) increased from 58.1 +/- 4.5 mL x kg(-1) x min(-1) to 64.3 +/- 3.9 mL x kg(-1) x min(-1) (P < 0.01); b) lactate threshold improved from 47.8 +/- 5.3 mL x kg(-1) x min(-1) to 55.4 +/- 4.1 mL x kg(-1) x min(-1) (P < 0.01); c) running economy was also improved by 6.7% (P < 0.05); d) distance covered during a match increased by 20% in the training group (P < 0.01); e) number of sprints increased by 100% (P < 0.01); f) number of involvements with the ball increased by 24% (P < 0.05); g) the average work intensity during a soccer match, measured as percent of maximal heart rate, was enhanced from 82.7 +/- 3.4% to 85.6 +/- 3.1% (P < 0.05); and h) no changes were found in maximal vertical jumping height, strength, speed, kicking velocity, kicking precision, or quality of passes after the training period. The control group showed no changes in any of the tested parameters.
Enhanced aerobic endurance in soccer players improved soccer performance by increasing the distance covered, enhancing work intensity, and increasing the number of sprints and involvements with the ball during a match.
To investigate the effects of replacing a portion of endurance training by strength training on exercise performance, 14 competitive cyclists were divided into an experimental (E; n = 6) and a control (C; n = 8) group. Both groups received a training program of 9 weeks. The total training volume for both groups was the same [E: 8.8 (1.1) h/week; C: 8.9 (1.7) h/week], but 37% of training for E consisted of explosive-type strength training, whilst C received endurance training only. Simulated time trial performance (TT), short-term performance (STP), maximal workload (Wmax) and gross (GE) and delta efficiency (DE) were measured before, after 4 weeks and at the end of the training program (9 weeks). No significant group-by-training effects for the markers of endurance performance (TT and Wmax) were found after 9 weeks, although after 4 weeks, these markers had only increased (P < 0.05) in E. STP decreased (P < 0.05) in C, whereas no changes were observed in E. For DE, a significant group-by-training interaction (P < 0.05) was found, and for GE the group-by-training interaction was not significant. It is concluded that replacing a portion of endurance training by explosive strength training prevents a decrease in STP without compromising gains in endurance performance of trained cyclists.
The aim of this experiment was to examine the effects of maximal strength training with emphasis on neural adaptations on strength- and endurance-performance for endurance trained athletes. Nineteen male cross-country skiers about 19.7 +/- 4.0 years of age and a maximal oxygen uptake (VO(2 max)) of 69.4 +/- 2.2 mL x kg(-1) x min(-1) were randomly assigned to a training group (n = 9) or a control group (n = 10). Strength training was performed, three times a week for 8 weeks, using a cable pulley simulating the movements in double poling in cross-country skiing, and consisted of three sets of six repetitions at a workload of 85% of one repetition maximum emphasizing maximal mobilization of force in the concentric movement. One repetition maximum improved significantly from 40.3 +/- 4.5 to 44.3 +/- 4.9 kg. Time to peak force (TPF) was reduced by 50 and 60% on two different submaximal workloads. Endurance performance measured as time to exhaustion (TTE) on a double poling ski ergometer at maximum aerobic velocity, improved from 6.49 to 10.18 min; 20.5% over the control group. Work economy changed significantly from 1.02 +/- 0.14 to 0.74 +/- 0.10 mL x kg(-0.67) x min(-1). Maximal strength training with emphasis on neural adaptations improves strength, particularly rate of force development, and improves aerobic endurance performance by improved work economy.
Improved oxygen uptake improves soccer performance as regards distance covered, involvements with the ball, and number of sprints. Large improvements in oxygen uptake have been shown using interval running. A similar physiological load arising from interval running could be obtained using the soccer ball in training.
The main aim was to study physiological adaptations to a 10 week high intensity aerobic interval training program performed by professional youth soccer players, using a soccer specific ball dribbling track.
Eleven youth soccer players with a mean (SD) age of 16.9 (0.4) years performed high intensity aerobic interval training sessions twice per week for 10 weeks in addition to normal soccer training. The specific aerobic training consisted of four sets of 4 min work periods dribbling a soccer ball around a specially designed track at 90-95% of maximal heart frequency, with a 3 min recovery jog at 70% of maximal heart frequency between intervals.
Mean VO2max improved significantly from 63.4 (5.6) to 69.8 (6.6) ml kg(-1) min(-1), or 183.3 (13.2) to 201.5 (16.2) ml kg(-0.75) min(-1) (p<0.001). Squat jump and counter movement jump height increased significantly from 37.7 (6.2) to 40.3 (6.1) cm and 52.0 (4.0) to 53.4 (4.2) cm, respectively (p<0.05). No significant changes in body mass, running economy, rate of force development, or 10 m sprint times occurred.
Performing high intensity 4 min intervals dribbling a soccer ball around a specially designed track together with regular soccer training is effective for improving the VO2max of soccer players, with no negative interference effects on strength, jumping ability, and sprinting performance.
The present study compared the effects of aerobic endurance training at different intensities and with different methods matched for total work and frequency. Responses in maximal oxygen uptake (VO2max), stroke volume of the heart (SV), blood volume, lactate threshold (LT), and running economy (CR) were examined.
Forty healthy, nonsmoking, moderately trained male subjects were randomly assigned to one of four groups:1) long slow distance (70% maximal heart rate; HRmax); 2)lactate threshold (85% HRmax); 3) 15/15 interval running (15 s of running at 90-95% HRmax followed by 15 s of active resting at 70% HRmax); and 4) 4 x 4 min of interval running (4 min of running at 90-95% HRmax followed by 3 min of active resting at 70%HRmax). All four training protocols resulted in similar total oxygen consumption and were performed 3 d.wk for 8 wk.
High-intensity aerobic interval training resulted in significantly increased VO2max compared with long slow distance and lactate-threshold training intensities (P<0.01). The percentage increases for the 15/15 and 4 x 4 min groups were 5.5 and 7.2%, respectively, reflecting increases in V O2max from 60.5 to 64.4 mL x kg(-1) x min(-1) and 55.5 to 60.4 mL x kg(-1) x min(-1). SV increased significantly by approximately 10% after interval training (P<0.05).
: High-aerobic intensity endurance interval training is significantly more effective than performing the same total work at either lactate threshold or at 70% HRmax, in improving VO2max. The changes in VO2max correspond with changes in SV, indicating a close link between the two.
The present study investigated the effect of maximal strength training on running economy (RE) at 70% of maximal oxygen consumption (V[spacing dot above]O2max) and time to exhaustion at maximal aerobic speed (MAS). Responses in one repetition maximum (1RM) and rate of force development (RFD) in half-squats, maximal oxygen consumption, RE, and time to exhaustion at MAS were examined.
Seventeen well-trained (nine male and eight female) runners were randomly assigned into either an intervention or a control group. The intervention group (four males and four females) performed half-squats, four sets of four repetitions maximum, three times per week for 8 wk, as a supplement to their normal endurance training. The control group continued their normal endurance training during the same period.
The intervention manifested significant improvements in 1RM (33.2%), RFD (26.0%), RE (5.0%), and time to exhaustion at MAS (21.3%). No changes were found in V[spacing dot above]O2max or body weight. The control group exhibited no changes from pre to post values in any of the parameters.
Maximal strength training for 8 wk improved RE and increased time to exhaustion at MAS among well-trained, long-distance runners, without change in maximal oxygen uptake or body weight.
The purpose of this study was to determine the effects of a running-specific, periodized strength training program (performed over the specific period [8 weeks] of a 16-week macrocycle) on endurance-trained runners' capacity to maintain stride length during running bouts at competitive speeds. Eighteen well-trained middle-distance runners completed the study (personal bests for 1500 and 5000 m of 3 minutes 57 seconds +/- 12 seconds and 15 minutes 24 seconds +/- 36 seconds). They were randomly assigned to each of the following groups (6 per group): periodized strength group, performing a periodized strength training program over the 8-week specific (intervention) period (2 sessions per week); nonperiodized strength group, performing the same strength training exercises as the periodized group over the specific period but with no week-to-week variations; and a control group, performing no strength training at all during the specific period. The percentage of loss in the stride length (cm)/speed (m.s) (SLS) ratio was measured by comparing the mean SLS during the first and third (last) group of the total repetitions, respectively, included in each of the interval training sessions performed at race speeds during the competition period that followed the specific period. Significant differences (p < 0.05) were found in mean percentage of SLS loss between the 3 study groups, with the periodized strength group showing no significant SLS change (0.36 +/- 0.95%) and the 2 other groups showing a moderate or high SLS loss (-1.22 +/- 1.5% and -3.05 +/- 1.2% for the nonperiodized strength and control groups, respectively). In conclusion, periodized, running-specific strength training minimizes the loss of stride length that typically occurs in endurance runners during fatiguing running bouts.
To determine whether various intensities of aerobic training differentially affect aerobic capacity as well as resting HR and resting blood pressure (BP).
Sixty-one health young adult subjects were matched for sex and VO2max and were randomly assigned to a moderate- (50% VO2 reserve (VO2R), vigorous (75% VO2R), near-maximal-intensity (95% VO2R), or a nonexercising control group. Intensity during exercise was controlled by having the subjects maintain target HR based on HR reserve. Exercise volume (and thus energy expenditure) was controlled across the three training groups by varying duration and frequency. Fifty-five subjects completed a 6-wk training protocol on a stationary bicycle ergometer and pre- and posttesting. During the final 4 wk, the moderate-intensity group exercised for 60 min, 4 d.wk the vigorous-intensity group exercised for 40 min, 4 d.wk and the near-maximal-intensity group exercised 3 d.wk performing 5 min at 75% VO2R followed by five intervals of 5 min at 95% VO2R and 5 min at 50% VO2R.
VO2max significantly increased in all exercising groups by 7.2, 4.8, and 3.4 mL.min.kg in the near-maximal-, the vigorous-, and the moderate-intensity groups, respectively. Percent increases in the near-maximal- (20.6%), the vigorous- (14.3%), and the moderate-intensity (10.0%) groups were all significantly different from each other (P < 0.05). There were no significant changes in resting HR and BP in any group.
When volume of exercise is controlled, higher intensities of exercise are more effective for improving VO2max than lower intensities of exercise in healthy, young adults.
Perspectives in the development of speed-strength preparation in the development of jumper
- Y U Verkhoshansky
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Aerobic endurance training improves soccer performance
- J Helgerud
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