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At least 181 records · Page 10Linked to original sources

PubMed2005

Activation of A1 and A2 noradrenergic neurons in response to running in the rat.

Since running accompanied with blood lactate accumulation stimulates the release of adrenocorticotropic hormone (ACTH), running above the lactate threshold (LT) acts as stress (running stress). To examine whether A1/A2 noradrenergic neurons that project to the hypothalamus activate under running stress, c-Fos immunohistochemistry was used to compare the effects of running with or without stress response on A1/A2 noradrenergic neurons. Blood lactate and plasma ACTH concentrations significantly increased in the running stress group, but not in the running without stress response and control groups, confirming different physiological impacts between different intensity of running with or without stress. Running stress markedly increased c-Fos accumulation in the A1/A2 noradrenergic neurons. Running without stress response also induced a significant increase in c-Fos expression in the A1/A2 noradrenergic neurons, and the percentage of the increase was smaller than that of running stress. The extent of c-Fos expression in the A1/A2 noradrenergic neurons correlates with exercise intensity, signifying that this neuronal activation is running speed-dependent. We thus suggest that A1/A2 noradrenergic neurons are activated in response to not only running stress, but also to other physiological running, enhanced by non-stressful running. These findings will be helpful in studies of specific neurocircuits and in identifying their functions in response to running at different intensities.

Adaptation, Physiological↗

PubMed2003

Kenyan dominance in distance running.

Critical physiological factors for performance in running are maximal oxygen consumption (VO(2max)), fractional VO(2max) utilization and running economy. While Kenyan and Caucasian elite runners are able to reach very high, but similar maximal oxygen uptake levels, the VO(2max) of black South African elite runners seems to be slightly lower. Moreover, the studies of black and white South African runners indicate that the former are able to sustain the highest fraction of VO(2max) during long distance running. Results on adolescent Kenyan and Caucasian boys show that these boys are running at a similar percentage of VO(2max) during competition. Kenyan elite runners, however, appear to be able to run at a high % of VO(2max) which must then have been achieved by training. A lower energy cost of running has been demonstrated in Kenyan elite runners and in untrained adolescent Kenyan boys compared to their Caucasian counterparts. In agreement with this are the results from studies on black South African elite runners who have shown similar low energy costs during running as the Kenyan elite runners. The good running economy cannot be explained by differences in muscle fibre type as they are the same in Kenyan and Caucasian runners. The same is true when comparing untrained adolescent Kenyan boys with their Caucasian counterparts. A difference exists in BMI and body shape, and the Kenyans long, slender legs could be advantageous when running as the energy cost when running is a function of leg mass. Studies comparing the response to training of Kenyans and Caucasians have shown similar trainability with respect to VO(2max), running economy and oxidative enzymes. Taken all these data together it appears that running at a high fractional VO(2max) and having a good running economy may be the primary factors favouring the good performance of endurance athletes rather than them having a higher VO(2max) than other elite runners. In addition to having the proper genes to shape their bodies and thereby contributing to a good running economy, the Kenyan elite runners have trained effectively and used their potential to be in the upper range both in regard to VO(2max) and to a high utilization of this capacity during endurance running.

Adaptation, Physiological↗

PubMed2001

The energy cost of running on grass compared to soft dry beach sand.

This study compared the energy cost (EC) (J x kg(-1) x m(-1)) of running on grass and soft dry beach sand. Seven male and 5 female recreational runners performed steady state running trials on grass in shoes at 8, 11 and 14 km x h(-1). Steady state sand runs, both barefoot and in shoes, were also attempted at 8 km x h(-1) and approximately 11 km x h(-1). One additional female attempted the grass and sand runs at 8 km x h(-1) only. Net total EC was determined from net aerobic EC (steady state VO2, VCO2 and RER) and net anaerobic EC (net lactate accumulation). When comparing the surface effects (grass, sand bare foot and sand in shoes) of running at 8 km x h(-1) (133.3 m x min(-1)) in 9 subjects who most accurately maintained that speed (133.3 +/- 2.2 m x min(-1)), no differences (P>0.05) existed between the net aerobic, anaerobic and total EC of sand running barefoot or in shoes, but these measures were all significantly greater (P<0.05) than the corresponding values when running on grass. Similarly, when all running speed trials (n = 87) performed by all subjects (n = 13) for each surface condition were combined for analysis, the sand bare foot and sand in shoes values for net aerobic EC, net anaerobic EC and net total EC were significantly greater (P<0.001) than the grass running measures, but not significantly different (P>0.05) from each other. Expressed as ratios of sand to grass running EC coefficients, the sand running barefoot and sand in shoes running trials at 8 km x h(-1) revealed values of 1.6 and 1.5 for net aerobic EC, 3.7 and 2.7 for net anaerobic EC and 1.6 and 1.5 for net total EC respectively. For all running speeds combined, these coefficients were 1.5 and 1.4 for net aerobic EC, 2.5 and 2.3 for net anaerobic EC and 1.5 and 1.5 for net total EC for sand running barefoot and in shoes respectively. Sand running may provide a low impact, but high EC training stimulus.

Adult↗

PubMed2001

Specific pulmonary responses during the cycle-run succession in triathletes.

The aim of the present study was to investigate the relationship between alterations in pulmonary function (i.e., diffusing capacity for carbon monoxide and pulmonary volumes) and the ventilatory response elicited during the cycle-run succession in triathletes. Ten well-trained triathletes performed three exercises: 1) 30 min cycling plus 20 min of running, termed the cycle-run succession; 2) 30 min cycling; and 3) 20 min running. Before and 10 min after each trial, the triathletes underwent pulmonary function testing, including spirometry and diffusing capacity for carbon monoxide. During all trials, ventilatory data were collected every minute using an automated breath-by-breath system. The ventilatory response was significantly higher in the run subsequent to cycling as compared with the run performed independently (P<0.001). There was no change in pulmonary volumes before and after exercises; however, the diffusing capacity for carbon monoxide and the transfer coefficient were similarly decreased (P<0.05) after cycling and the cycle-run succession, but not decreased after running. The increase in minute ventilation in the run segment of the cycle-run succession versus in running alone was significantly correlated with the decrease in diffusing capacity for carbon monoxide measured after versus before the cycle-run succession (P<0.01). This same increase in ventilation was also correlated with the decrease in diffusing capacity measured after the cycle-run succession versus after cycling alone (P<0.03). These results suggest the possibility that the DLCO decrease contributes in part to the ventilatory increase noted in the run after cycling during the cycle-run succession of the triathlon.

Adult↗

PubMed1996

A 1% treadmill grade most accurately reflects the energetic cost of outdoor running.

When running indoors on a treadmill, the lack of air resistance results in a lower energy cost compared with running outdoors at the same velocity. A slight incline of the treadmill gradient can be used to increase the energy cost in compensation. The aim of this study was to determine the treadmill gradient that most accurately reflects the energy cost of outdoor running. Nine trained male runners, thoroughly habituated to treadmill running, ran for 6 min at six different velocities (2.92, 3.33, 3.75, 4.17, 4.58 and 5.0 m s-1) with 6 min recovery between runs. This routine was repeated six times, five times on a treadmill set at different grades (0%, 0%, 1%, 2%, 3%) and once outdoors along a level road. Duplicate collections of expired air were taken during the final 2 min of each run to determine oxygen consumption. The repeatability of the methodology was confirmed by high correlations (r = 0.99) and non-significant differences between the duplicate expired air collections and between the repeated runs at 0% grade. The relationship between oxygen uptake (VO2) and velocity for each grade was highly linear (r > 0.99). At the two lowest velocities, VO2 during road running was not significantly different from treadmill running at 0% or 1% grade, but was significantly less than 2% and 3% grade. For 3.75 m s-1, the VO2 during road running was significantly different from treadmill running at 0%, 2% and 3% grades but not from 1% grade. For 4.17 and 4.58 m s-1, the VO2 during road running was not significantly different from that at 1% or 2% grade but was significantly greater than 0% grade and significantly less than 3% grade. At 5.0 m s-1, the VO2 for road running fell between the VO2 value for 1% and 2% grade treadmill running but was not significantly different from any of the treadmill grade conditions. This study demonstrates equality of the energetic cost of treadmill and outdoor running with the use of a 1% treadmill grade over a duration of approximately 5 min and at velocities between 2.92 and 5.0 m s-1.

Adult↗

PubMed2003

Effect of cycling cadence on subsequent 3 km running performance in well trained triathletes.

OBJECTIVES: To investigate the effect of three cycling cadences on a subsequent 3000 m track running performance in well trained triathletes. METHODS: Nine triathletes completed a maximal cycling test, three cycle-run succession sessions (20 minutes of cycling + a 3000 m run) in random order, and one isolated run (3000 m). During the cycling bout of the cycle-run sessions, subjects had to maintain for 20 minutes one of the three cycling cadences corresponding to 60, 80, and 100 rpm. The metabolic intensity during these cycling bouts corresponded approximately to the cycling competition intensity of our subjects during a sprint triathlon (> 80% VO(2)max). RESULTS: A significant effect of the prior cycling exercise was found on middle distance running performance without any cadence effect (625.7 (40.1), 630.0 (44.8), 637.7 (57.9), and 583.0 (28.3) seconds for the 60 rpm run, 80 rpm run, 100 rpm run, and isolated run respectively). However, during the first 500 m of the run, stride rate and running velocity were significantly higher after cycling at 80 or 100 rpm than at 60 rpm (p<0.05). Furthermore, the choice of 60 rpm was associated with a higher fraction of VO(2)max sustained during running compared with the other conditions (p<0.05). CONCLUSIONS: The results confirm the alteration in running performance completed after the cycling event compared with the isolated run. However, no significant effect of the cadence was observed within the range usually used by triathletes.

Bicycling↗

PubMed1998

Hypertrophy of rat plantaris muscle fibers after voluntary running with increasing loads.

There have been no systematic comparisons of skeletal muscle adaptations in response to voluntary wheel running under controlled loading conditions. To accomplish this, a voluntary running wheel for rats and mice was developed in which a known load can be controlled and monitored electronically. Five-week-old male Sprague-Dawley rats (10 rats/group) were assigned randomly to either a 1) sedentary control group (Control); 2) voluntary exercised with no load (Run-No-Load) group; or 3) voluntary exercised with additional load (Run-Load) group for 8 wk. The load for the Run-Load group was progressively increased to reach approximately 60% of body weight during the last week of training. The proportions of fast glycolytic (FG), fast oxidative glycolytic (FOG), or slow oxidative (SO) fibers in the plantaris were similar in all groups. The absolute and relative plantaris weights were greater in the Run-Load group compared with the Control and Run-No-Load groups. The mean fiber cross-sectional areas of FG, FOG, and SO fibers were 20, 25, and 15% greater in the Run-Load than in Control rats. In addition, these fiber types were 16, 21, and 12% larger in Run-Load than in Run-No-Load rats. The muscle weights and mean cross-sectional areas of each fiber type were highly correlated with the average running distances and total work performed in the Run-Load, but not the Run-No-Load, group. The slope of the relationship between fiber size and running distance and total work performed was significant for each fiber type but was higher for FG and FOG fibers compared with SO fibers. These data show that the load on a rat running voluntarily can determine the magnitude of a hypertrophic response and the population of motor units that are recruited to perform at a given loading condition.

Animals↗

PubMed2004

Extended voluntary running inhibits exercise-induced adult hippocampal progenitor proliferation in the spontaneously hypertensive rat.

Previous work has shown that voluntary running increases cell proliferation and neurogenesis in the dentate gyrus of the adult hippocampus. Here we report that long-term running for 24 days results in a down-regulation of hippocampal progenitor proliferation to one-half the level of nonrunning controls compared with a fivefold increase in progenitor proliferation seen after 9 days of voluntary running (short-term running). The negative effects seen on proliferation after 24 days of running were prevented by restricting daily running distances (by 30-50%) during 24 days. Long-term running for 24 days increases the response of the hypothalamic-pituitary-adrenal axis, with an increase in adrenal gland weight and increased plasma corticosterone levels, as well as decreased thymus weight, indicating a stress response as a possible mediator of decreased progenitor proliferation. Furthermore, the negative effects seen on the observed stress response after 24 days of running were prevented by restricting daily running distance. Short-term running did not alter these stress parameters compared with nonrunning controls. However, it increased phosphorylated cyclic AMP response element binding protein (pCREB) in the dentate gyrus, an increase that was not seen in nonrunning controls or after 24 days of running. Taken together, these data suggest that voluntary running does not always enhance proliferation and that the decrease in progenitor proliferation seen in long-term running is possibly mediated by mechanisms involving a stress response in the animal. However, a moderate level of long-term running was able to prevent the negative stress-related changes seen in unrestricted long-term running.

Adrenal Glands↗

PubMed2003

Physiological cost of running while wearing spring-boots.

The purpose of the study was to investigate the physiological cost of running in spring-boots compared with running in running shoes at different speeds. During testing, subjects (n = 7) completed running trials while wearing spring-boots and running shoes. Three speed conditions (2.23, 2.68, and 3.13 m.s(-1)) were completed per shoe condition (i.e., spring-boots and running shoes). Rate of oxygen consumption (Vo(2)), heart rate (HR), rating of perceived exertion (RPE), and stride frequency were recorded for each condition. Order of shoe conditions was balanced, with speeds tested continuously from slow to fast. There was no difference in Vo(2), HR, or RPE between shoe conditions across speeds (p > 0.05). Stride frequency was lower during running in spring-boots vs. running shoes at each speed (speed of spring-boots vs. running shoes for 2.23 m x s(-1): 69.9 +/- 2.9 strides x min(-1) vs. 75.6 +/- 3.5 strides x min(-1); for 2.68 m x s(-1): 71.3 +/- 5.2 strides x min(-1) vs. 79.4 +/- 5.0 strides x min(-1); for 3.13 m x s(-1): 73.6 +/- 7.3 strides x min(-1) vs. 83.1 +/- 8.2 strides x min(-1); p < 0.05). Despite the added mass to the lower extremity and change in stride frequency during running in spring-boots, the physiological cost of running was similar to that of running in running shoes. Exercising while running in spring-boots may provide less impact force with no change in running economy.

Adult↗

PubMed2006

The basis for prescribed ability group run speeds and distances in U.S. Army basic combat training.

During the first few days of Army Basic Combat Training (BCT), recruits take a running test and after completing this test they are ranked from fast to slow. Four roughly equal-sized "ability groups" are established from these rankings and recruits run together in these groups for their physical training during BCT. In the past, there has been no formal guidance regarding how fast or how far these ability groups should run. To fill this void, this study provides guidance for running speeds and distances during BCT. The major considerations included are: (1) minimizing injuries, (2) the initial aerobic fitness level of recruits, (3) historical improvements in run times during BCT, (4) historical running speeds of the slower individuals in each ability group, (5) running speeds that must be achieved to "pass" the 2-mile run in BCT, (6) the gender composition of the ability groups, and (7) recommendations from the trainers and field testing. Three databases were analyzed that contained a total of 16,716 men and 11,600 women. Four steps were used in the analyses: (1) establishment of run-time cut points for representative ability groups, (2) determination of initial (starting) run speeds, (3) estimation of changes in run speeds with training, and (4) establishment of run speeds and distances for each week of BCT. Efforts were made to (1) keep the running speeds between 70% and 83% of the estimated maximal oxygen uptake (VO2max) for all ability groups, (2) consider the 2-mile running pace of the slower individuals in each ability group, and (3) keep the total running distance for the two slower ability groups below a total of 25 miles, the apparent threshold for increasing injury incidence. A chart provides speeds and distances for each ability group at each week of BCT. Using these recommended speeds and distances should allow trainees to improve their aerobic fitness, pass the Army Physical Fitness Test, and minimize injuries that result in lost training time and, ultimately, lower fitness levels.

Adolescent↗

PubMed2006

Conditioned taste avoidance induced by forced and voluntary wheel running in rats.

Voluntary exercise by rats running in a freely rotating wheel (free wheel) produces conditioned taste avoidance (CTA) of a flavored solution consumed before running [e.g., Lett, B.T., Grant, V.L., 1996. Wheel running induces conditioned taste aversion in rats trained while hungry and thirsty. Physiol. Behav. 59, 699-702]. Forced exercise, swimming or running, also produces CTA in rats [e.g., Masaki, T., Nakajima, S., 2006. Taste aversion induced by forced swimming, voluntary running, forced running, and lithium chloride injection treatments. Physiol. Behav. 88, 411-416]. Energy expenditure may be the critical factor in producing such CTA. If so, forced running in a motorized running wheel should produce CTA equivalent to that produced by a similar amount of voluntary running. In two experiments, we compared forced running in a motorized wheel with voluntary running in a free wheel. Mean distance run over 30 min was equated as closely as possible in the two apparatuses. Both types of exercise produced CTA relative to sedentary, locked-wheel controls. However, voluntary running produced greater CTA than forced running. We consider differences between running in the free and motorized wheels that may account for the differences in strength of CTA.

Animals↗

PubMed1987

Induction of voluntary prolonged running by rats.

The rat is widely used in studies of the metabolic and physiological effects of physical exercise. The most commonly used form of exercise is running on treadmills or mechanically driven running wheels. Rats will not voluntarily run significant distances, under normal circumstances. If rats are exposed to running wheels with food freely available, only very limited activity normally occurs. When rats with access to a running wheel are restricted to a fixed amount of food, presented once per day, consistent running occurs. The running is spontaneous and very sensitive to the amount of food provided. Six 6-wk-old rats of 197 g mean body wt were induced to run for 139 days. The distance run increased rapidly over a 20-day initial period on a food supply of 15 g/day (vs. 19.5 g/day consumption by sedentary controls). From day 20 to day 139 the mean distance run was described by the regression equation distance (m/day) = 10,410 - 37.9 X days. Food provided was varied according to distance run, ranging from 15 to 18 g/day, and was normally 17.5 g/day. Thus a food deprivation of 10% of normal consumption will result in mean distances run of approximately 8,000 m/day. The use of pair-fed control animals without access to a wheel allows the conduct of experiments to test the effects of chronic long-distance running. The running is spontaneous; thus the technique avoids the complications accompanying techniques that force running.

Animals↗

PubMed1996

Increase in energy cost of running at the end of a triathlon.

The purpose of the present study was to verify the increase in energy cost of running at the end of a triathlon. A group 11 trained male subjects performed a triathlon (15-km swimming, 40-km cycling, 10-km running). At least 1 week later the subjects ran 10-km as a control at the same pace as the triathlon. Oxygen uptake (VO2), ventilation (VE) and heart rate (HR) were measured during both 10-km runs with a portable telemetry system. Blood samples were taken prior to the start of the triathlon and control run, after swimming, cycling, triathlon run and control run. Compared to the control values the results demonstrated that triathlon running elicited a significantly higher (P < 0.005) mean VO2 [51.2 (SEM 0.4) vs 47.8 (SEM 0.4) ml.min-1.kg-1] VE [86 (SEM 4.2) vs 74 (SEM 5.3) l.min-1], and HR [162 (SEM 2) vs 156 (SEM 1.9) beats.min-1)]. The triathlon run induced a greater loss in body mass than the control run [2 (SEM 0.2) vs 0.6 (SEM 0.2) kg], and a greater decrease in plasma volume [14.4% (SEM 1.5) vs 6.7% (SEM 0.9)]. The lactate concentrations observed at the end of both 10-km runs did not differ [2.9 (SEM 0.2) vs 2.5 (SEM 0.2) m.mol.l-1]. Plasma free fatty acids concentrations were higher (P < 0.01) after the triathlon than after the control run [1.53 (SEM 0.2) to 0.51 (SEM 0.07) mmol.l-1]. Plasma creatine kinase concentrations rose under both conditions from 58 (SEM 12) to 112 (SEM 14) UI.l-1 after the triathlon, and from 61 (SEM 7) to 80 (SEM 6) UI.l-1 after the control run. This outdoor study of running economy at the end of an Olympic distance triathlon demonstrated a decrease in running efficiency.

Adult↗

PubMed1996

Increased ventilation in runners during running as compared to walking at similar metabolic rates.

At similar levels of carbon dioxide production (VCO2) and oxygen consumption (VO2), runners have been shown to have a greater minute ventilation (VE) during running as compared to walking. The mechanism responsible for these differences has yet to be identified. To determine if these differences are a result of differences in acid-base status, potassium (K+), norepinephrine and/or epinephrine levels, seven well-trained runners completed walk and run tests at similar VO2 and VCO2 levels. The occurrence of entrainment of the breathing and stride frequencies during both walking and running was also determined. VE was significantly greater during the run as compared to the walk, 73.7 (2.2) versus 68.6 (2.0) l.min-1, respectively, despite the similarity in VO2 and VCO2 levels. Alveolar ventilation was not significantly different between the run and the walk, 60.4 (4.7) versus 59.6 (4.4) l.min-1, respectively. Dead space ventilation was found to be significantly greater during running as compared to walking, 13.3 (3.2) versus 9.0 (4.7) l.min-1, respectively. The increases in VE were due to increases in breathing frequency and decreases in tidal volume during the run as compared to the walk. Arterial partial pressures of CO2 (PaCO2) were not significantly different when comparing walking and running to rest values nor when comparing walking and running. Arterial pH was significantly lower during walking as compared to rest and running. Bicarbonate levels were significantly lower during walking as compared to rest. Lactate was significantly greater during walking as compared to rest and to running. K+ levels were significantly higher during walking and running as compared to rest. Epinephrine and norepinephrine levels were not significantly different between running and walking. During the walk, six of the seven subjects entrained their breathing frequency to the stride frequency, and during the run three of the seven subjects demonstrated entrainment. Results from this investigation do not support mediation of VE under the present experimental conditions by changes in arterial levels of humoral factors previously shown to influence VE.

Acid-Base Equilibrium↗

PubMed2005

Recovery of running performance following muscle-damaging exercise: relationship to brain IL-1beta.

Recovery following muscle-damaging downhill running is associated with increased muscle inflammatory cytokines. Various inflammatory challenges can also increase cytokines in the brain, which have been linked to sickness behaviors, including fatigue, but little is known about the brain cytokine response to stressful exercise. We used a downhill running model to determine the relationship between brain IL-1beta and recovery of running performance. Male C57BL/6 mice were assigned to: downhill (DH), uphill (UH), or non-running control (Con) groups and run on a treadmill at 22 m/min and -14% or 14% grade, for 150 min. Following the run, a subset of DH and UH was placed into activity wheel cages where voluntary running activity was measured for 7 days. A second subset was run to fatigue on a motorized treadmill at 36 m/min, 8% grade at 24, 48, and 96 h post-up/downhill run. A third subset of DH, UH, and Con mice had brains dissected and assayed for IL-1beta at 24 and 48 h. DH resulted in delayed recovery of both voluntary wheel-running and treadmill running to fatigue as compared to UH (p < .05). DH was also associated with increased IL-1beta concentrations in cortex (at 24 and 48 h) and cerebellum (24 h) as compared to UH and Con. UH was not different than Con in any brain region. Eccentric-biased downhill running results in an increase in plasma CK and delayed recovery in running performance, as compared to the more metabolically demanding uphill running, and this was associated with increased concentrations of IL-1beta in regions of the brain responsible for movement, coordination, motivation, perception of effort, and pain.

Animals↗

PubMed1994

The validity and accuracy of blood lactate measurements for prediction of maximal endurance running capacity. Dependency of analyzed blood media in combination with different designs of the exercise test.

The effect of using different blood lactate sampling sites in combination with different exercise test designs on the validity and accuracy for prediction of maximal endurance running velocity was investigated. Ten aerobically all-round trained firemen and nine aerobically endurance trained long-distance runners performed six differently designed treadmill running blood lactate accumulation tests. Each test consisted of five consecutive running periods on a treadmill of either 4, 6 or 8 min duration, with a mean increase in running velocity between each period of either 0.25 or 0.5 m.s-1. The corresponding treadmill running velocity to a lactate concentration of 4.0 mmol.l-1 in capillary and venous hemolysed blood and plasma for each running velocity. The mean running velocity from a maximal 12 km run for the firemen and a maximal 21 km run for the runners served as the reference of maximal endurance running velocity. There were both significant (p < 0.001) and similar relationships (r = 0.86-0.94) and no difference in mean prediction error between the predicted and measured maximal endurance running velocities with all tested protocols. However, there was a high risk of making both over- and underestimations (5% to -4%). The lowest risk of making an inaccurate prediction was found when a running duration of 8 min for each running period was used in combination with an increase in running velocity of 0.25 m.s-1, and the lactate measurements were performed in hemolysed capillary blood.

Adult↗

PubMed2002

Effects of multicycle-run training on triathlete performance.

The purpose of this study was to determine the effect of triathlon training using multiple, short cycle-run sequences (multicycle-run training) on cycle-run performance. Twelve competitive triathletes, randomized into two groups, underwent multicycle-run training or normal training for 6 weeks. During this period, baseline training remained the same for both groups, and only the high-intensity component differed. The differentiated exercises were performed at or above 100% maximal aerobic velocity. The improvements in overall cycle-run performance were similar (3.3 +/- 1.4 % and 6.1 +/- 1.7% rise in Performance in multicycle-run and normal training, respectively). However, the improvement in performance was significantly greater for the multicycle-run training (-11.2 +/- 6.8 s versus -1.2 +/- 7. 7 s for multicycle-run training and normal training, respectively) during both the cycle-run change and the first 333-m lap, which together are termed the cycle-run transition. We concluded that 6 weeks of multicycle-run training did not induce greater improvement in cycle-run performance than did normal training in competitive triathletes. However, it did induce significant improvement in the cycle-run transition. This finding indicates that multicycle-run training may help competitive triathletes to develop greater skill and better physiological adaptations during this critical transition period of the triathlon race.

Adaptation, Physiological↗

PubMed1990

Running addiction: measurement and associated psychological characteristics.

Runners frequently become addicted to running and continue to run even when it is detrimental to their health. In the present study a paper and pencil test to measure running addiction, the running addiction scale (RAS) was constructed and evaluated and used to investigate the psychological correlates of running addiction. The RAS, symptom check list, locus of control scale, commitment to running scale (CR), and a questionnaire about the individual's running habits and degree of addiction were administered to 32 male and 15 female runners. The results suggest that the RAS is reliable and valid, correlating with self-rated addiction. The CR score was correlated with self-rated addiction for males but not for females suggesting that the RAS and CR measure different characteristics and that for female runners commitment to running can occur without addiction. Large gender differences were found in the correlations between the RAS, CR, run frequency, and run duration with the personality, mood, and locus of control scores. Running addiction was found to be associated with high frequency of running and with positive personality characteristics but not with mood enhancement, while the duration of running was found to be associated with mood enhancement. These results suggest that the benefits of running to mood may be obtained without addiction.

Adult↗