Physiological characteristics of elite short- and long-distance triathletes

The purpose of this study was to compare the physiological responses in cycling and running of elite short-distance (ShD) and long-distance (LD) triathletes. Fifteen elite male triathletes participating in the World Championships were divided into two groups (ShD and LD) and performed a laboratory trial that comprised submaximal treadmill running, maximal then submaximal ergometry cycling and then an additional submaximal run. 'In situ' best ShD triathlon performances were also analysed for each athlete. ShD demonstrated a significantly faster swim time than LD whereas V˙O_2max (ml kg^–1 min^–1), cycling economy (W l^–1 min^–1), peak power output ( , W) and ventilatory threshold (%V˙O_2max) were all similar between ShD and LD. Moreover, there were no differences between the two groups in the change (%) in running economy from the first to the second running bout. Swimming time was correlated to (r=–0.76; P<0.05) and economy (r=–0.89; P<0.01) in the ShD athletes. Also, cycling time in the triathlon was correlated to (r=–0.83; P<0.05) in LD. In conclusion, ShD triathletes had a faster swimming time but did not exhibit different maximal or submaximal physiological characteristics measured in cycling and running than LD triathletes. Electronic Publication     

A new approach to assessing maximal aerobic power in children: the Odense School Child Study

Summary In two experiments maximal aerobic power calculated from maximal mechanical power (W _max) was evaluated in 39 children aged 9–11 years. A maximal multi-stage cycle ergometer exercise test was used with an increase in work load every 3 min. In the first experiment oxygen consumption was measured in 18 children during each of the prescribed work loads and a correction factor was calculated to estimate using the equation . An appropriate increase in work rate based on height was determined for boys (0.16 W · cm^–1) and girls (0.15 W · cm^–1) respectively. In the second experiment 21 children performed a maximal cycle ergometer exercise test twice. In addition to the procedure in the first experiment a similar exercise test was performed, but without measurement of oxygen uptake. Calculated correlated significantly (p<0.01) with those values measured in both boys (r=0.90) and girls (r=0.95) respectively, and the standard error of estimation for (calculated) on (measured) wass less than 3.2%. Two expressions of relative work load (% and %W _max) were established and found to be closely correlated. The relative work load in % could be predicted from the relative work load in % W _max with an average standard error of 3.8%. The data demonstrate that calculated based on a maximal multi-stage exercise test provides an accurate and valid estimate of      

Anaerobic and aerobic power of top athletes

Summary In this study the alactic anaerobic and aerobic power of top level sprinters, long-distance runners, and untrained students were compared. Maximal oxygen uptake was measured during a progressive test on a treadmill. The anaerobic power was estimated according to a newly developed bicycle ergometer technique. As reported elsewhere, the maximal oxygen uptake is very high in twelfe long-distance runners (77.6±2.7 ml/kg·min⁻¹) whereas the maximal oxygen uptake of six sprinters amounts to 60.1±5.9 ml/kg·min⁻¹. The average alactic anaerobic power of a control group of 32 students was 710 W or 10.1±1.2 W/kg. Significantly lower results were obtained by long-distance runners (551 W or 8.93 W/kg) whereas significantly higher results were obtained by sprinters (1,021 W or 14.16 W/kg). In top level athletes, but not in the control group, a negative relationship was found between aerobic power and anaerobic power.     

The effect of endurance training on changes in purine metabolism: a longitudinal study of competitive long-distance runners

The purpose of the study was to characterize the changes in purine metabolism in long-distance runners in the main phases of their 1-year training cycle. Nine male athletes competing in distances 5 and 10 km at national/regional level, mean age 22.9 ± 0.6 years, practising sport for 8.6 ± 0.3 years, participated in the study. The changes in plasma concentrations of hypoxanthine (Hx), xanthine (X) and uric acid (UA) and the activity of the enzyme HGPRT in red blood cells haemolysate were followed in four characteristic points of the annual training cycle: preparatory phase (specific subphase), competition period, transition period and preparatory phase (intermediate subphase). Resting and postexercise plasma concentrations of X and, Hx and HGPRT activity changed significantly during 1-year training cycle. Significant changes in postexercise Hx values between training phases were found, from 9.3 μmol l⁻¹ in competition period to 22.9 μmol l⁻¹ in transition period (Friedmann’s ANOVA, P < 0.01). Postexercise UA values ranged from 371 to 399 μmol l⁻¹ and did not change significantly between training phases. An increase in resting (from 52.0 to 58.4 IMP mg⁻¹ Hb min⁻¹, P < 0.05) and postexercise (from 70.7 to 76.2 IMP mg⁻¹ Hb min⁻¹, not significant) HGPRT activity between the specific preparation and competition period was observed. In the transition period, Hx postexercise concentration increased (22.9 μmol l⁻¹, P < 0.01) and HGPRT postexercise activity decreased (58.8 IMP mg⁻¹ Hb min⁻¹, P < 0.01) significantly. The results indicate that the level of plasma Hx at rest and after standard exercise may be a useful tool for monitoring the adaptation of energetic processes in different training phases and support the overload/overtraining diagnosis.     

Aerobic and anaerobic contribution to Wingate test performance in sprint and middle-distance runners

We investigated the aerobic and anaerobic contributions to performance during the Wingate test in sprint and middle-distance runners and whether they were related to the peak aerobic and anaerobic performances determined by two commonly used tests: the force-velocity test and an incremental aerobic exercise test. A group of 14 male competitive runners participated: 7 sprinters, aged 20.7 (SEM 1.3) years, competing in 50, 100 and 200-m events and 7 middle-distance runners, aged 20.0 (SEM 1.0) years, competing in 800, 1,000 and 1,500 m-events. The oxygen uptake ( ) was recorded breath-by-breath during the test (30 s) and during the first 20 s of recovery. Blood samples for venous plasma lactate concentrations were drawn at rest before the start of the test and during the 20-min recovery period. During the Wingate test mean power ( ) was determined and three values of mechanical efficiency, one individual and two arbitrary, 16% and 25%, were used to calculate the contributions of work by aerobic ( _{aer,ind,16%,25%}) and anaerobic ( _{an,ind,16%,25%}) processes. Peak anaerobic power ( _an,peak) was estimated by the force-velocity test and maximal aerobic energy expenditure ( _aer,peak) was determined during an incremental aerobic exercise test. During the Wingate test, the middle-distance runners had a significantly greater than the sprinters (P < 0.001), who had significantly greater venous plasma lactate concentrations (P < 0.001). Moreover, _{aer,ind,16%,25%} were also significantly higher (P < 0.05) in the middle-distance runners [ _aer,ind 45 (SEM 4) % vs 28 (SEM 2) %; _aer,16% 30 (SEM 3) % vs 19 (SEM 2) %; _aer,25% 46 (SEM 3) % vs 29 (SEM 2)%]; _{an,ind,16%,25%} in the sprint runners (P < 0.05) [ _an,ind 72 (SEM 3) % vs 55 (SEM 4) %; _an,16% 81 (SEM 2) % vs 70 (SEM 3) %; _an,25% 71 (SEM 2) % vs 54 (SEM 3) %]. The _aer,ind/ _aer,peak and × _an,ind/ _an,peak ratios, however, were not significantly different between the two groups of athletes. These results would indicate that the sprinters and middle-distance runners used preferentially a metabolic system according to their speciality. Nevertheless, under the conditions of its experiment, they seemed to rely on the same percentage of both peak anaerobic and peak aerobic performance for a given exercise task.     

Effects of acute moderate hypoxia on anaerobic capacity in endurance-trained runners

While there is some controversy whether anaerobic capacity might be improved after altitude training little is known about changes in anaerobic capacity during hypoxic exposure in highly trained athletes. In order to analyze the effects of acute moderate normobaric hypoxia on anaerobic capacity, 18 male competitive triathletes, middle- and long-distance runners performed 2 supra- treadmill runs with the same speed, one in normoxia and one after 4 h exposure to normobaric hypoxia (FiO₂ 0.15), for estimation of their maximal accumulated oxygen deficit (MAOD) and measurement of peak capillary lactate and peak capillary ammonia concentration. MAOD was not significantly different in normoxia and in moderate hypoxia while time to exhaustion and accumulated O₂ uptake were significantly (P < 0.001) reduced in hypoxia compared to normoxia by 28 and 45%, respectively. The reduction in time to exhaustion was significantly correlated to the decrement in accumulated O₂ uptake (R = 0.730, P = 0.001). In hypoxia, there was a tendency for peak capillary lactate concentration to be decreased compared to normoxia (12.9 ± 2.1 vs. 13.8 ± 2.2 mmol l⁻¹, P = 0.082); peak capillary ammonia concentration was significantly decreased in hypoxia (97 ± 52 vs. 121 ± 44 μmol l⁻¹, P = 0.032). In conclusion, anaerobic capacity is not significantly changed during acute exposure to moderate hypoxia in endurance-trained athletes. The performance reduction during all-out exercise of short duration has to be attributed to the decrement in aerobic capacity.     

Cardiorespiratory response to treadmill and bicycle exercise in runners

Summary Maximal aerobic power and related variables during submaximal work were determined on the bicycle ergometer and on the treadmill in nine long-distance runners and in nine control subjects.During submaximal work, heart rate and pulmonary ventilation were similar with the two exercise procedures in each group, but the runners had lower values than the control subjects.During maximal exercise, oxygen uptake and pulmonary ventilation reached higher levels on the treadmill than on the bicycle ergometer. The difference in max was not significant in the control subjects (4.4%), but was more pronounced (12.8%) and highly significant (p<0.01) in the runners. The intergroup differences for max between runners and controls were more marked during treadmill running (17.3%) than during bicycle exercise (8.5%).It is concluded that the differences between the max values obtained on the bicycle ergometer and on the treadmill are influenced by the training conditions of the subjects and that bicycle ergometry leads to a marked underestimation of maximal oxygen uptake in runners.     

Relationships between skeletal muscle characteristics and aerobic performance in sedentary and active subjects

Summary Forty-eight sedentary and 39 quite active or well-trained men participated in this study. Muscle biopsy samples were taken from the vastus lateralis for the determination of fiber type composition (I, IIa, IIb), fiber type area, and assay of the following enzymes: malate dehydrogenase (MDH), 3-hydroxyacyl CoA dehydrogenase (HADH) and oxoglutarate dehydrogenase (OGDH). Maximal oxygen uptake ( ) was determined with a progressive cycle ergometer test, while endurance performance or maximal aerobic capacity (MAC) was defined as the total work output during a 90-min cycle ergometer test. Correlation analysis revealed no evidence of association between fiber type composition and kg^–1 or MAC kg^–1 in sedentary subjects, while active men exhibited significant correlation between % type I (r=0.52), % type IIb (r=–0.31) and kg^–1. Enzyme activities were not significantly correlated with MAC kg^–1 and kg^–1 in sedentary men while active men exhibited significant correlation for the three enzymes (0.37r0.51) with kg^–1. These results show that the contribution of muscle fiber type and enzyme activities to aerobic performance may be inflated from a statistiscal point of view by the training status heterogeneity of subjects. They also suggest that variation in these muscle characteristics does not account for the individual differences in aerobic performance of subjects who have never trained before. Therefore, the assessment of muscle characteristics is not as useful as originally thought for the detection of individuals with a high potential for endurance performance among untrained subjects.     

Aerobic performance capacity in athletes

Summary Maximal oxygen uptake (max O₂) in leg and arm work, succinate dehydrogenase activity (SDH) and percentage of slow twitch fibers (%ST fibers) in M. vastus lateralis (VL), M. gastrocnemius c.l. (GL) and M. deltoideus (D) were studied in 89 athletes practising 11 different sport events. It was found that maximal oxygen uptake correlated positively with %ST fibers and SDH activity in M. VL. The SDH activity and %ST fibers in M. VL correlated also with one another. The results suggest that oxidative capacity of the muscles is not the limiting factor for maximal oxygen uptake. The role of the oxidative capacity of the muscles might be important during submaximal work of long duration and when a relatively small muscle mass is activated (long-distance running). Max O₂ might be the most important determinant of performance when large muscle mass is activated during maximal work of a duration from several minutes up to 1 h (cross-country skiing).     

Benefits of training at moderate altitude versus sea level training in amateur runners

After more than 25 years of research on altitude training (AT) there is no consensus regarding either the training programme at altitude or the effects of AT on performance at sea level. Based on a review of the research work on AT, we investigated combined base training and interval training at moderate altitude and compared immediate and delayed effects on sea level performance with those following similar sea level training (SLT). The altitude group (AG, 10 male amateur runners) trained at 2315 m (natural altitude) and the sea level group (SLG, 12 male amateur runners) at 187 m. Both groups performed 7 days of base training (running on a trail) lasting between 60 and 90 min a day and 5 days of interval training (speed and hill runs) for between 10 and 45 min a day. Incremental exercise tests were performed 1 week before (t ₁), 3 days after (t ₂) and 16 days after (t ₃) the 12-day main training period. Within AG, exercise performance improved fromt ₁ tot ₂ by 8% (P<0.05) and fromt ₂ tot ₃ by 8% (P<0.05). Maximum oxygen uptake ( ) increased fromt ₂ tot ₃ by 10% (P<0.05). Within SLG exercise performance increased fromt ₂ tot ₃ by 8% (P<0.05). Att ₃, relative and absolute in AG were significantly higher in comparison with SLG (P=0.005 andP=0.046 respectively). The improved performance 3 days after AT may be explained in part by an increased oxygen uptake at submaximal exercise intensities without a change in . Further enhancement in performance 2 weeks after AT, however, seems to have been due to the clearly enhanced . Progressive cardiovascular adjustments might have contributed primarily to the time-dependent improvements observed after AT, possibly by an enhanced stroke volume overcompensating the reduced heart rates during submaximal exercise. In conclusion, our findings would suggest that training at a moderate natural altitude improves performance at sea level more than SLT. Combining base and interval training with regulation of intensity by training at constant heart rates during acclimatization at altitude would seem to be a successful training regimen for amateur runners. Most beneficial effects became apparent during the subsequent SLT around 2 weeks after return from altitude. Therefore, we are convinced that AT should be reconsidered as a potent tool for enhancing aerobic capacity, at least in non-elite athletes.     

Maximal strength-training effects on force-velocity and force-power relationships explain increases in aerobic performance in humans

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·kg^–0.67 body mass·min^–1 or 61 ml·kg^–1·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. Electronic Publication     

Critical determinants of endurance performance in middle-aged and elderly endurance runners with heterogeneous training habits

Summary The current investigation was designed to determine which factor or what combination of factors would best account for distance running performance in middle-aged and elderly runners (mean age 57.5 years SD±9.7) with heterogeneous training habits. Among 35 independent variables which were arbitrarily selected as possible prerequisites in the distance running performance of these runners, oxygen uptake at lactate threshold (LT) (r=0.781∼0.889), maximal oxygen uptake (r=0.751∼0.886), and chronological age (r=−0.736∼−0.886) were found to be the 3 predictor variables showing the highest correlations with the mean running velocity at 5 km (V _{5 km}), 10 km (V _{10 km}), and marathon (V _M). When all independent variables were used in a multiple regression analysis, any 3 or 4 variables selected from among at LT, chronological age, systolic blood pressure (SBP), atherogenic index (AI), and Katsura index (KI) were found to give the best explanation ofV _{5 km},V _{10 km}, orV _M in a combined linear model. Linear multiple regression equations constructed for predicting the running performances were:V _{5 km}=0.046X ₁−0.026X ₂−0.0056X ₃+5.17,V _{10 km}=0.028X ₁−0.028X ₂−0.190X ₄−1.34X ₅+6.45, andV _M=−0.0400X ₂−0.324X ₄−1.16X ₅+7.36, where at LT (ml·min⁻¹·kg⁻¹),X ₂ = chronological age,X ₃=SBP,X ₄=AI, andX ₅=KI. We suggest that distance running performance of middle-aged and elderly runners could be predicted with a relatively high accuracy by a single predictor of at LT or , or by a combination of either of these predictors with more easily measurable indices such as age, AI, KI, or SBP. The prediction equations which have been developed can be applied to a larger population of middle-aged and elderly runners. Data were collected at the Human Performance Laboratory, Hiroshima University     

Anaerobic and aerobic components during arm-crank exercise in sprint and middle-distance swimmers

Summary The purpose of this investigation was to compare anaerobic and aerobic components measured during arm exercise in sprint and middle-distance swimmers and to investigate whether the peak anaerobic power :peak aerobic power ratio (W _{an, peak} :W aer, peak) was related to specialization for the event and to performance. TheW _{an, peak} force at zero velocity (F ₀), and velocity at zero-force (₀),W _{aer, peak}, peak oxygen uptake ( O_2peak), and ventilatory threshold (Th _v ) were compared during arm exercise tests in sprint (group I,n = 8) and middle-distance (group II,n = 9) competitive male swimmers. Anaerobic indices were estimated by the force-velocity test, an anaerobic test using incremental braking forces; aerobic indices were measured during an incremental aerobic exercise test (30 W · min^–1). TheW _{an, peak} andW aer, peak were greater in group I [828 (SEM 70) W; 236 (SEM 12) W] than in group II [678 (SEM 28) W; 230 (SEM 5) W], but the differences were not significant. There were also no significant differences observed between the mean values ofF ₀, ₀, O_2peak, and Th _v . TheW _{an, peak}:W _{aer, peak}, however, was significantly higher in sprint swimmers (t = 3.08,P < 0.01). In seven of the swimmers, who had recently performed both the 100-m and 400-m front crawl, a relationship existed between their swim time and theW _{an, peak}:Waer,peak (100m:r = –0.80,P<0.05 and 400m:r=+0.75,P<0.05). In conclusion, during arm-crank exercise, we did not observe significant differences in anaerobic and aerobic components between sprint and middle-distance swimmers. However, the results of the present study demonstrated the usefulness of theW _{an, peak} :W _{aer, peak} in the physiological evaluation of swimmers as it reflects the proportion of anaerobic to aerobic systems involved in the supply of energy.     

Physical performance capacity of children in Norway

Summary This paper tested the hypothesis that social isolation of children brings about a reduced pattern of habitual physical activity, influences body composition during growth, and hampers development of physical performance capacity. Two cohorts of children were studied, one living at or close to the center, the other living in the periphery of the community of Lom in Southern Norway. The two cohorts of children differed in their patterns of physical behavior, but were otherwise similar in genetic traits, nutrition, and environmental conditions.During a 4-year period the two cohorts of children were tested annually. The center children were leaner, and their maximal oxygen uptake and forced expiratory volume were greater in all years of growth when related to body size.     

Aerobic performance capacity in paraplegic subjects

Summary To determine adaptation to prolonged exercise in paraplegics, maximal O₂ uptake ( ) and lactate threshold (LT) were evaluated during an arm cranking exercise in nine patients (P) and nine able-bodied (AB) subjects.Mean averaged 25.1 and 31.6 ml · min^–1 · kg^–1 in P and AB groups respectively. in P was found to be directly related to the level of spinal injury: the higher the lesion the lower the uptake. Lactate threshold expressed as a percentage of was higher in P (59%) than in AB (43%), and close to that observed in armtrained athletes.Since training has less effect on in paraplegics than in able-bodied subjects, attributable to a deficiency in the circulatory adaptation of paraplegics to exercise, the observed differences between AB and P in lactate threshold and submaximal exercise indicate that the possible effect of training in paraplegics is located at the level of intracellular chemistry, with a diminution in glycogenolysis (higher LT) and a higher rate of lipid utilization (lower RQ).     

Changes in aerobic fitness and body fat during army recruit training

Summary Aerobic fitness and related indices were evaluated in 254 soldiers at the beginning and near the end of initial army recruit training. Aerobic fitness in terms of maximal aerobic power was predicted from the Astrand-Ryhming submaximal heart rate bicycle test. Estimated vO₂ max increased by 8%, 42.0–45.3 ml/kg·min. Accompanying this increase in aerobic capacity was a decline in body fat content without a change in body weight. It is concluded that army recruit training at the time of this study was effective in terms of increasing aerobic work capacity and reducing excess body fat.HQ UNFICYP BFPO 567     

Cardiovascular and respiratory responses to submaximal exercise training in the thoroughbred horse

Cardiovascular and respiratory responses to submaximal exercise training were investigated in 6 thoroughbred racehorses. Oxygen uptake, heart rate (HR) and arteriovenous oxygen content difference were measured during incremental treadmill exercise tests, before and after 7 weeks of treadmill training. Cardiac output during exercise was calculated by the direct Fick technique. Maximal oxygen uptake ( ) was increased by 23% after training, from 129.7 ml/kg/min to 160.0 ml/kg/min. The treadmill speed at which was attained increased by 19%. The increased aerobic power after training was associated with an increase in maximal cardiac output and stroke volume, a decrease in arteriovenous oxygen difference and no change in HR. There was no change in pulmonary ventilation during exercise at . Mean mixed venous oxygen content ( ) at before training was 2.8±1.0 ml/100 ml blood (mean ±SE). After training the value was 8.6±1.4 ml/100 ml blood. It is concluded that the increase in after training in the horse is dependant on augmented blood flow, and is not dependent on either increased arterial oxygen content or arteriovenous oxygen content difference. Cardiac capacity to pump blood is therefore of primary importance as a determinant of increases in due to training in the horse.     

Physical work capacity and effect of endurance training in visually handicapped boys and young male adults

Summary The purpose of the present study was to evaluate the relationship between several physical fitness parameters and eyesight divided into 3 grades in visually handicapped boys and young male adults, and to investigate the effect of mild exercise training on physical and psychic symptoms as well as cardiorespiratory fitness. Four subjects were totally blind (TB), 6 were semi-blind (SB) and 27 had amblyopia (AM). Physical fitness tests consisted of maximal oxygen uptake (V _{O 2max}), maximal pedalling speed and power, maximal stepping rate, and isometric knee extention strength. Compared with AM and SB groups, the TB group was inferior in all physical fitness parameters. Especially,V _{O 2max} in TB (26 ml · kg^–1 · min^–1) was about 56% of that in agematched Japanese sighted subjects and was significantly low compared with the AM and SB groups. Both muscle strength and maximal pedalling power corresponded to about 50% that of the age-matched sighted group. Six SB and 4 TB students (¯x=17.7 years) were trained for 6 weeks on a bicycle ergometer at an intensity of 50%V _{O 2max}. Training was undertaken for 3 days per week and maintained for 60 min per session. After training, physical and psychic symptoms determined by the Cornell Medical Index improved significantly. These results indicate that low physical work capacity in visually handicapped boys and young male adults is due to the lack of physical activity, and that mild endurance training is effective in improving physical and psychic symptoms as well as cardiorespiratory fitness.     

Relative functional buffering capacity in 400-meter runners,long-distance runners and untrained individuals

Buffering is a factor which influences performance in short and middle-term endurance by compensating exercise acidosis. The aim of the study was to establish whether respiration parameters are a relative measure of buffering capacity and to study the influence of buffering on specific performance parameters. Three groups (each of ten subjects) with defined degrees of adaptation [untrained (UT), aerobic-trained (AeT) and elite 400-m runners (AnT) with a best time of 48.47 ± 0.98 s] were examined in an incremental multi-stage test on the treadmill. Breath-by-breath gas analysis was performed using mass spectrometry and computer routines. Serum lactate concentrations were determined at each exercise level until subjective exhaustion. A value for the relative functional buffering capacity (re1FB) was calculated using exercise metabolic parameters. Running speed at the lactate threshold was used as the starting point of buffering. The start of respiratory compensation of acidosis (RCP) was taken as the endpoint of buffering. RCP was determined at the point of decrease in end-tidal CO₂ content (CO₂-ET). Re1FB was given in percent of buffering to running speed at RCP. Group AnT attained the same maximum performance data (maximum running speed, maximum rate of O₂ consumption) as group AeT. However, these values were attained in group AnT with a significantly higher re1FB (AnT: 31.0±3.2% vs. AeT: 15.7±3.9%,P < 0.0001), while a higher lactate threshold indicated a greater oxidative capacity in AeT (AeT: 3.07±0.26 m · s^–1 vs. AnT: 2.68±0.22 m · s^–1). It is concluded that the combination of ventilatory parameters and determining the LT seems to be a useful measure for the total amount of buffering during high-intensity exercise. The higher content of buffer-active proteins in sprinters' muscles may be considered the main cause of their higher re1FB.     

A prediction equation for indirect assessment of anaerobic threshold in male distance runners

Summary The predictability of anaerobic threshold (AT) from maximal aerobic power, distance running performance, chronological age, and total running distance achieved on the treadmill (TRD) was investigated in a sample of 53 male distance runners, 17–23 years of age. The dependent variable was oxygen uptake ( ) at which AT was detected (i. e., @AT). A regression analysis of the data indicated @AT could be predicted from the following four measurements with a multipleR=0.831 and a standard error of the estimate of 2.66 ml · min⁻¹ · kg⁻¹: (67.9±5.7 ml · min⁻¹ · kg⁻¹), 1,500-m running performance (254.5±14.2 s), TRD (6.82±1.13 km), and age (19.4±2.2 years). When independent variables were limited to (X ₁) and 1,500-m running performance (X ₂) for simpler assessment, a multipleR=0.806 and a standard error of the estimate of 2.76 ml · min⁻¹ · kg⁻¹ were computed. A useful prediction equation with this predictive accuracy was considered to be @AT= 0.386X₁−0.128X₂+57.11. To determine if the prediction equation developed for the 53 male distance runners could be generalized to other samples, cross-validation of the equation was tested, using 21 different distance runners, 17–22 years of age. A high correlation (R=0.927) was obtained between @AT predicted from the above equation and directly measured @AT. It is concluded that the generalized equation may be applicable to young distance runners for indirect assessment of @AT. This study was supported by grants from The Descente Foundation for the Promotion of Sports Science, awarded to K. Tanaka