Maximal Aerobic Test Research Articles

Aerobic endurance, energy expenditure, and serum leptin response in obese, sedentary, prepubertal children and adolescents participating in a short-term treadmill protocol

Objective We analyzed aerobic endurance, energy expenditure, and serum leptin concentrations during programmed, short-term exercise in a group of untrained, obese children and adolescents. Methods This was a prospective, controlled study of prepubertal males and females ages 6 to 11 y. Group 1 ( n = 40) comprised obese children, and group 2 comprised similarly aged non-obese children ( n = 16). The children completed a stepwise maximal aerobic endurance test (Bruce protocol) on a treadmill. The variables measured included anthropometric indexes, serum leptin, and physiologic indexes. Results Maximal oxygen consumption (corrected for body weight) values were 29.9 ± 6.7 mL · kg −1 · min −1 in group 1 and 47.2 ± 5.3 mL · kg −1 · min −1 in group 2 ( P < 0.05). The number of exercise steps was smaller in group 1 (3.7 ± 0.7 versus 5.3 ± 0.4, P < 0.05), as was time to exhaustion (9.3 ± 1.9 min versus 15.1 ± 1.9 min, P < 0.05). However, the energy cost of the exercise did not differ significantly between groups (57.7 ± 17.8 kcal versus 65.2 ± 17.6 kcal), indicating greater energy expenditure for less performance in the obese children. Initial leptin concentrations were higher in group 1 (24.0 ± 13.1 ng/mL versus 1.6 ± 1.7 ng/mL, P < 0.001), and exercise did not significantly modify these findings. Conclusions Obese children were seriously unfit and paid a high energy price for the treadmill test. Initial leptin concentrations were very high in the obese children, in the range of concentrations found in obese adults. No significant change in leptin concentration was observed at the end of the test, probably because of the short duration of the activity.

Effect of exercise on natriuretic peptides in plasma and urine in chronic heart failure

Background: Plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are elevated in chronic heart failure (CHF). ANP is known to be increased during exercise in healthy subjects and CHF, while the response in BNP during exercise is less clear and does not exist in C-type natriuretic peptide (CNP) and aquaporin-2 (AQP2) in either healthy subjects or CHF. Methods: Eleven patients with CHF and eleven healthy subjects performed a maximal aerobic exercise test. ANP and BNP in plasma were determined every 3 min and at maximum exercise by radioimmunoassay (RIA) and CNP and AQP2 in urine were determined before and after the exercise test by RIA. Results: The absolute increase in BNP during exercise was higher in patients with CHF (CHF: 4.1 pmol/l; healthy subjects: 1.3 pmol/l, P<0.05) and was positively correlated to BNP at rest (P<0.05), while the absolute increase in ANP during exercise was the same in the two groups (CHF: 4.2 pmol/l; healthy subjects: 6.8 pmol/l, not significant, NS). In CHF, exercise did not change either u-CNP excretion (rest: 9.8 ng/mmol creatinine; after exercise: 8.8 ng/mmol, NS) or u-AQP2 (rest: 466 ng/mmol creatinine; after exercise: 517 ng/mmol creatinine, NS) as well as in healthy subjects where u-CNP (rest: 9.7 ng/mmol creatinine; after exercise: 9.2 ng/mmol creatinine) and u-AQP2 (rest: 283 ng/mmol creatinine; after exercise: 307 ng/mmol creatinine) were the same at rest and after exercise. Conclusion: The absolute increase in BNP during exercise is higher in patients with CHF compared to healthy subjects. It is suggested that this is a compensatory phenomenon to improve the exercise capacity in CHF, and that BNP is a more important factor in cardiovascular homeostasis during exercise in CHF than ANP.

An Evaluation of Standardizing Target Ventilation for Eucapnic Voluntary Hyperventilation Using FEV1

Athletes are required to provide objective documentation of exercise‐induced bronchoconstriction (EIB) to use β2‐agonists during Olympic competition. A positive response to bronchial provocation by eucapnic voluntary hyperventilation (EVH) is considered acceptable confirmation of EIB. Thirty times forced expiratory volume in the first second (FEV1) is recommended as EVH target ventilation (TV), an intensity intended to estimate 85% of maximal voluntary ventilation (MVV). There is a paucity of data examining the accuracy of predicting MVV from FEV1 in elite athletes. The purpose of this study was to evaluate the efficacy of 30 × FEV1 as standardized EVH TV. Maximal minute ventilation during exercise (VEmax) and pulmonary function of 78 elite winter athletes (25 males, 53 females; 25 EIB positive, 53 normal) were analyzed retrospectively. Adequacy and variability of the equation was ascertained by examining the ratio of EVH TV (30 × FEV1) to VEmax. VEmax was 99 ± 11% of predicted MVV (35 × FEV1) and was positively related (r = 0.85, p ≤ 0.05). TV was 88 ± 9% of VEmax (range: 64–109). For elite athletes, the high variability in 30 × FEV1 to standardize TV for EVH may result in under‐diagnosis for low‐end outliers. Since VEmax of elite endurance athletes is typically known (via maximal aerobic testing) we recommend 85% VEmax as a more accurate and reliable method to establish EVH TV for this group; if VEmax is not available, then 85% of measured MVV may be used.

MAXIMAL AEROBIC AND ANAEROBIC EXERCISE EFFECTS ON MOOD STATES

Studies have used the Profile of Mood States (POMS) in relation to exercise. Low to moderate exercise has been linked to positive mood changes such as vigor and exhilaration. Most studies have looked at POMS immediately pre and post submaximal exercise. Morgan et al. (1980) used State Anxiety to show that post-maximal exercise increases in anxiety had decreased in 5 to 30 minutes of recovery. PURPOSE To determine maximal exercise effects on the mood states of college-aged males and females. METHODS The short POMS version was used for the 3 exercise protocols, Bruce and Ramp for aerobic exercise and Wingate for anaerobic exercise. Subjects (N=19) were oriented with an initial visit while the other visits were randomized. The POMS was given pre-exercise, post-exercise and 20 min into recovery. RESULTS Due to the small sample size and the lack of sphericity in the data, a multivariate analysis was not appropriate. Therefore, 6 separate one-way repeated measures ANOVAS were calculated that reflected the 6 scales of the POMS. To protect against inflation of alpha, a Bonferroni adjustment to the p value was utilized. A Tukey LSD post-hoc analysis was performed on the scales with significant differences and indicated that only the scores on tension/anxiety and fatigue were significant and only in conjunction with the maximal aerobic exercise tests. The time course for the tension/anxiety score showed significant decreases for both treadmill tests from post-exercise (Bruce=3.80; Ramp = 3.70) to 20 min into recovery (Bruce=1.35; Ramp = 1.25; p < 0.05). Fatigue followed a course similar to what would be expected following maximal exercise. Significant differences occurred within each maximal aerobic protocol (Bruce pre-exercise=2.45, postexercise=7.55, 20 min into recovery=2.80, p < 0.05; Ramp pre-exercise=2.90, post-exercise=9.45, 20 min into recovery=2.80, p < 0.05). There were no significant differences in VO2max between the two protocols. CONCLUSIONS These results confirm those found by Morgan et al. (1980) using the state anxiety measure.

Relationship between functional ability and physical fitness in juvenile idiopathic arthritis patients

Objective: To determine the relationship between aerobic and anaerobic physical fitness and functional ability in children with juvenile idiopathic arthritis (JIA).Methods: Eighteen children with JIA (age 7 to 14 yr., 3 male/15 female) performed a maximal aerobic exercise test and a Wingate anaerobic exercise test. Functional ability was concurrently assessed using the Childhood Health Assessment Questionnaire (CHAQ).Results: A low relationship between aerobic fitness and functional ability was found (r=0.0 to 0.4, p>0.05, except for eating r=0.46, p<0.05). The correlations between anaerobic physical fitness and functional ability in JIA patients were strong (r=0.5 to 0.75, p<0.05). This indicated a good relationship between anaerobic fitness and functional ability.Conclusion: The strong association between anaerobic physical fitness and functional ability showed the importance of anaerobic physical fitness for children with JIA.

Test-Retest Reliability of the Aerobic Power Index Test in Patients with Chronic Fatigue Syndrome

AbstractUse of maximal aerobic exercise testing in a chronically ill population may not only deter potential subjects from participating in trials, or returning for repeat trials, but may also result in the exacerbation of symptoms related to CFS. The Aerobic Power Index represents a submaximal exercise test that forms the aerobic component of the Tri-Level Fitness Profile. This incremental bike test has a predetermined termination point based on a target heart rate (THR) of 75% of age predicted heart rate maximum, making successful completion of the test more likely in chronically ill subjects. The aim of this study was to determine reliability of the Aerobic Power Index in 20 CFS subjects. Results for the 17 subjects who reached THR for both trials, demonstrated high reliability for watts per kilogram and oxygen uptake (ml*kg-1*min-1), as demonstrated by an intraclass correlation coefficient (ICC) of .97 and .91, respectively, while RPE resulted in moderate reliability (ICC = .87). The results of this s...

Central and peripheral cardiovascular adaptations to exercise in endurance-trained children.

Stroke volume (SV) response to exercise depends on changes in cardiac filling, intrinsic myocardial contractility and left ventricular afterload. The aim of the present study was to identify whether these variables are influenced by endurance training in pre-pubertal children during a maximal cycle test. SV, cardiac output (Doppler echocardiography), left ventricular dimensions (time-movement echocardiography) as well as arterial pressure and systemic vascular resistances were assessed in 10 child cyclists (VO2max: 58.5 +/- 4.4 mL min-1 kg-1) and 13 untrained children (UTC) (VO2max: 45.9 +/- 6.7 mL min-1 kg-1). All variables were measured at the end of the resting period, during the final minute of each workload and during the last minute of the progressive maximal aerobic test. At rest and during exercise, stroke index was significantly higher in the child cyclists than in UTC. However, the SV patterns were strictly similar for both groups. Moreover, the patterns of diastolic and systolic left ventricular dimensions, and the pattern of systemic vascular resistance of the child cyclists mimicked those of the UTC. SV patterns, as well as their underlying mechanisms, were not altered by endurance training in children. This result implied that the higher maximal SV obtained in child cyclists depended on factors influencing resting SV, such as cardiac hypertrophy, augmented myocardium relaxation properties or expanded blood volume.

Influence of training habits on exercise-induced changes in plasma atrial and brain natriuretic peptide and urinary excretion of aquaporin-2 in healthy man

The purpose of this study was to quantify the influence of training habits on the changes in plasma atrial natriuretic peptide (ANP), plasma brain natriuretic peptide (BNP) and urine aquaporin-2 (u-AQP2) during exercise by studying trained and untrained healthy subjects. Eleven trained subjects (7 males, 4 females) and 10 untrained subjects (8 males, 2 females) performed a maximal aerobic exercise test. ANP and BNP were determined every 3 min and at maximum exercise by radioimmunoassay (RIA), and u-AQP2 was determined before and after the exercise test by RIA. The absolute increase in ANP during exercise was higher in the trained subjects (trained subjects: 5.6 pmol/L; untrained subjects: 2.4 pmol/L, p<0.05) and was positively correlated to ANP at rest (p<0.03). The maximum absolute increase in BNP during exercise was the same in the two groups (trained subjects: 0.5 pmol/L; untrained subjects: 0.6 pmol/L, NS) and tended to correlate positively with resting BNP in the trained subjects (p= 0.07). Exercise did not change u-AQP2 excretion in either trained subjects (rest: 372 ng/mmol creatinine; exercise: 314 ng/mmol creatinine, NS) or untrained subjects (rest: 263 ng/mmol creatinine; exercise: 338 ng/mmol creatinine, NS). The absolute increase in ANP during exercise was higher in trained subjects than in untrained subjects and was positively correlated to ANP at rest. This might reflect the normal cardiovascular adaptation to exercise. The increase in BNP during exercise was unrelated to training habits. Training habits did not affect the u-AQP2 excretion during exercise.

Anaerobic power and achievement of VO2 plateau in pre-pubertal boys.

A low anaerobic power has been proposed as a factor that may be limiting the achievement of a plateau in VO2 of children who perform maximal aerobic power tests. This study examined the frequency of plateau achievement in pre-pubertal children and compared VO2max, peak (PP) and mean (MP) anaerobic power in subjects who either achieved a plateau (PLAT) or did not (NO PLAT). Eighteen healthy pre-pubertal (Tanner Stage, pubic hair = 1) males (age = 9.1 1.6 yrs, ht = 134.4 +/- 9.7cm, wt = 33.3 +/- 9.2kg, VO2max = 40.0 +/- 6.7 ml x kg(-1) min(-1)) were tested. All subjects completed a 30 sec Wingate Anaerobic Test and a McMaster aerobic protocol to volitional fatigue on a cycle ergometer. Only 33% of the subjects met the PLAT criterion. No differences were found for PP or MP between those who achieved a plateau and those who did not (PLAT: PP= 6.3 +/- 0.8W/kg and MP = 5.2 +/- 0.7W/kg; NO PLAT: PP= 6.3 +/- 1.2 W/kg and MP = 5.2 +/- 1.3 W/kg). We conclude that anaerobic power is not a factor limiting the achievement of a plateau in VO2 of pre-pubertal boys who perform maximal aerobic power tests.

FORMOTEROL AND PERFORMANCE IN ELITE NON-ASTHMATIC ATHLETES

Purpose To determine the effect of formoterol (formoterol fumerate dihydrate) on the aerobic and anaerobic capacities of highly trained nonasthmatic athletes. Methods: 10 male athletes (age = 26.2 ± 0.9, VO2 max = 65.6 ± 2.4 ml.kg−1.min−1) with a negative methacholine challenge test (PC20 > 16 mg/ml) completed three identical exercise sessions differing only by the medication administered. Formoterol (F) a long-acting b-2 agonist, presently not approved for international competition by the I. O. C. Medical committee, was compared to Salbutamol (S), an accepted bronchodilator, and a placebo (P). Formoterol (12 μg), salbutamol (400 μg), or placebo was administered by a turbuhaler, ten minutes prior to exercise testing in a double blind, randomized, three-way crossover design. Testing sessions included a Wingate anaerobic test followed 15 minutes later by an incremental cycle ergometer test to exhaustion. Results: There was no significant difference in VO2 max (F = 66.5 ± 2.7; S = 67.8 ± 2.5; P = 67.5 ± 2.1 ml.kg−1.min−1) or Wingate peak power (F = 885 ± 40; S = 877 ± 44 watts). During the maximal aerobic test no difference was observed in maximum minute ventilation, respiratory exchange ratio, heart rate, or work between the three experimental conditions. There was also no difference in the Wingate anaerobic test variables, total work or fatigue index. Conclusion: Formoterol, administered in an aerosolized therapeutic dose does not have an ergogenic effect in elite nonasthmatic athletes. Supported by AstraZeneca

SEA-LEVEL PERFORMANCE IS ENHANCED BY ACUTE INTERMITTENT HYPOBARIC HYPOXIA

787 The goal of this project was to study to what extent intermittent exposure to altitude in a hypobaric chamber can improve performance at sea-level. Over a 10-day period, elite male triatletes trained two hours each day on a cycle ergometer placed in a hypobaric chamber (60-70% Heart Rate Reserve). Subjects trained at simulated altitude of 2.500 m (n=8) or at sea-level (n=8). Baseline measurements were done on a cycle ergometer at sea-level, which included an incremental test until exhaustion and a Wingate Anaerobic Test. Measurements were repeated 2 and 9 days after termination of the training period. Nine days after training in hypoxia, significant increases were seen in all important parameters of the maximal aerobic as well as the anaerobic test. A significant increase of 7.0% was seen in the mean maximal oxygen uptake per kg body weight (VO2max) (P<0.05), and the mean maximal power output per kg body weight (MPO) increased significantly with 7.4% (P<0.05). The mean anaerobic power (AnP) and the mean anaerobic capacity (AnC) increased both with 5.0% (P<0.05), and the Time until peak (Tpeak) decreased highly significantly with 37.7% (P<0.01). In the sea-level group, no significant changes were seen in the above mentioned parameters of both the maximal aerobic and maximal anaerobic test (resp. 3.5% increase in VO2max, 3.2%increase in MPO, 1.8% increase in AnP, 0.1% increase in AnC, and decrease in Tpeak of 13.7% at the second post-test). The results of this study indicate that intermittent hypobaric training can improve both the aerobic as well as the anaerobic energy supplying systems.

Neuromuscular characteristics and muscle power as determinants of 5-km running performance.

The purpose of this study was to investigate neuromuscular characteristics and muscle power as determinants of distance running performance. Seventeen male endurance athletes performed a 5-km time trial (5K) that included three separate constant-velocity 200-m laps during the course and a maximal 20-m speed (V20m) test on an indoor track, and running economy (RE) tests on a treadmill and on the track. Maximal anaerobic (MART) and aerobic running tests on the treadmill were used to determine maximal velocity in the MART (VMART), maximal oxygen uptake (VO2max), peak treadmill performance (VO2max demand), and respiratory compensation threshold (RCT). Velocity in the 5K (V5K) correlated positively (P < 0.05) with VO2max, VO2max demand, RCT, and RE, as well as with V20m and VMART. Regression analysis showed that RCT, track RE, and VMART were the most important determinants of V5K. V5K also correlated (P < 0.05) with contact times (CT) and stride rates in the maximal 20-m run (r = -0.49 and 0.58, respectively), as well as with the mean CT of the constant velocity laps during the 5K (r = -0.50). VMART correlated significantly with peak blood lactate concentration in MART (r = 0.59, P < 0.05), V20m (r = 0.87, P < 0.001), and CT in the maximal 20-m run (r = -0.61, P < 0.01). We conclude that neuromuscular characteristics and VMART were related to 5-km running performance in well trained endurance athletes. Relationships between VMART and neuromuscular and anaerobic characteristics suggest that VMART can be used as a measure of muscle power in endurance athletes.

ANAEROBIC POWER AND ACHIEVEMENT OF VO2 PLATEAU IN PRE-PUBERTAL BOYS966

A low anaerobic power has been proposed as a factor that may be limiting the achievement of a plateau in ˙VO2 of children who perform maximal aerobic power tests. This study examined the frequency of plateau achievement in pre-pubertal children and compared ˙VO2max, peak(PP) and mean (MP) anaerobic power in subjects who either achieved a plateau(PLAT) or did not (NO PLAT). Twenty healthy pre-pubertal (Tanner Stage, pubic hair=1) males (age=9.0 ± 1.6 yrs, ht=133.9 ± 9.9 cm, wt=33.3± 9.3 kg, ˙VO2max=40.1 ± 7.2 ml· kg-1·min-1) were tested. All subjects completed a 30 sec Wingate Anaerobic Test and a McMaster aerobic protocol to volitional fatigue on a cycle ergometer. ˙VO2 was measured breath by breath using a Medgraphics metabolic system. The criterion for plateau was an increase in˙VO2 in the last stage of exercise ≤ 2 S.D. of the mean increase of submaximal stages. Only 40% of the subjects met the PLAT criterion. No differences were found for PP or MP between those who achieved a plateau and those who did not (PLAT:PP=6.4 ± 0.8 W/kg and MP=5.2 ± 0.9 W/kg; NO PLAT: PP=6.2 ± 1.2 W/kg and MP=5.2 ± 1.3 W/kg. We conclude that anaerobic power may not be a factor limiting the achievement of a plateau in ˙VO2 of pre-pubertal boys who perform maximal aerobic power tests.

IMPORTANCE OF NEUROMUSCULAR AND METABOLIC DETERMINANTS OF 5 KM RUNNING PERFORMANCE 753

This study investigated the importance of neuromuscular characteristics, aerobic power and treadmill and track running economy on distance running performance. Endurance athletes (n=12) performed a 5 km time trial (5K) and maximal 20 m speed test (V20m) on a track and running economy (RE) tests on the treadmill and track. Maximal anaerobic and aerobic running tests on the treadmill were used for the determination of maximal anaerobic power(Pmax), maximal oxygen uptake (VO2max) and ventilatory threshold(VT). RE at 250 m·min-1 was worse during treadmill than track run (228.5 ± 11.5 and 205.2 ± 10.1 ml · min-1· kg-2/3, p<0.001, respectively). 5K time (18.0 ± 0.6 min) correlated significantly (p<0.05) with VT (r = -0.85), treadmill and track RE in ml · min-1 · kg-2/3 (r = 0.63 and r = 0.73, respectively), Pmax (r = -0.73) and V20m (r = -0.65). 5K time showed no significant correlation with VO2max or with RE in unit ml · kg-1 · min-1. Regression analysis revealed that VT and Pmax were the most important determinants of the 5K time. We conclude that besides of ventilatory threshold and running economy also the force and velocity characteristics of the neuromuscular system are important for the distance running performance. We also conclude that RE in ml · min-1 · kg-2/3 should be used instead of the RE in ml· kg-1 · min-1.

Validation de deux tests de détermination de la vitesse maximale aérobie (VMA) sur le terrain

Resume Les resultats de deux tests de determination de la vitesse maximale aerobie (VMA) sur le terrain (protocole continu derriere cycliste selon Brue et al, 1988 : TCT ; protocole discontinu avec des paliers de vitesse de 3 minutes et 1 minute de recuperation entre chaque palier: TDT) ont ete compares a ceux obtenus chez les memes sujets en laboratoire avec les memes protocoles continu (TCL) et discontinu (TDL) sur tapis roulant. L'etude a ete realisee chez 31 sujets masculins. La VO2max a ete mesuree en laboratoire et la VMA a ete convertie en VO2max predite a l'aide de la formule simplifiee de Leger et Mercier (1983) : VO2max (mL·min−1 kg−1) = 3,5 VMA (km·h−1). Pour les deux tests a protocole continu (TC) et a protocole discontinu (TD) il y a eu une excellente concordance entre les valeurs obtenues sur le terrain et en laboratoire (duree d'exercice, VMA, frequence cardiaque maximale : FCmax et lactatemie de fin d'exercice). Par rapport a TD, la duree des epreuves lors de TC a ete moindre (p

Adaptation of maximal aerobic and anaerobic tests for disabled swimmers.

The purpose of the present study was to submit disabled swimmers to two maximal swimming tests, and by comparing the physiological and performance responses of disabled and normal swimmers to determine if these adapted tests can be used to design training programmes for this particular class of swimmer. Two groups of disabled (n = 8 and 6) and two groups of normal competitive swimmers (n = 9 and 13) were respectively submitted to a functional maximal aerobic power test (FMAPT) and a maximal anaerobic lactic test (MANLT). For the disabled, the FMAPT included a slower initial speed and a slower increase in swimming speeds. In the maximal aerobic test, exercise duration, peak heart rate, and the maximal speed relative to the respective best time of a 100-m race [55.5 (SD 3.9) compared to 56.5 (SD 2.8)%] were not significantly different between the disabled and normal swimmers. Peak lactate concentration was, however, higher in the disabled swimmers [10.8 (SD 3.5) compared to 6.8 (SD 1.6)mmol.l-1]. In the MNALT, peak lactate concentration [14.3 (SD 4) compared to 16.8 (SD 1.9)mmol.l-1], and the maximal speed relative to the respective best time in a 100-m race [99.1 (SD 3.2) compared to 98.3 (SD 2.5)%] were not significantly different between the disabled and normal swimmers. These results would seem to indicate that functional maximal aerobic and anaerobic field tests could be used to evaluate and design training programmes for disabled competitive swimmers.

VersaClimbing elicits higher &amp;OV0312;O2max than does treadmill running or rowing ergometry

Collegiate varsity oarswomen and coxswain (N = 11) completed maximal aerobic exercise tests on a treadmill, a rowing ergometer, and a simulated climbing machine. Successful completion of each test was evidenced by a plateau in oxygen consumption in response to increasing work rates. VO2max (l.min-1), and minute ventilation (VE, l.min-1) at VO2max were significantly greater (P < 0.05) during simulated climbing compared to treadmill running and rowing ergometry. Maximal heart rate (beats.min-1) was significantly greater (P < 0.05) during climbing and running than during rowing. Findings indicate that progressive, incremental, whole-body climbing exercise elicits significantly greater VO2max values for collegiate oarswomen and coxswain than does graded treadmill running or progressive rowing ergometry.

Peak Power Production in Wheelchair Propulsion

The effect of resistance on sprint power and the relationship between sprint and aerobic power production in wheelchair propulsion was evaluated. Six able-bodied subjects performed nine 20-s sprint tests on a stationary wheelchair ergometer (varying workload of 0–22.4 Nm for each side) and an aerobic maximum wheelchair exercise test to study both anaerobic and aerobic power production. Ergometer data were analyzed unilaterally. Of all power and torque parameters, only maximal power output was independent of resisting load (mean value 375 W, one-sided). Mean sprint power output over 20 s (P mean; one-sided) increased from 21 W to 87 W. The highest power output, P5, calculated over a period of 5 s (unilateral) increased from 24 W to 101 W. The P mean and P5 reached more or less constant values at the final two levels of resistance. The observed increase in power output with increasing load is the result of a greater increase in torque compared to the decrease in velocity. Mean maximal power in the maximal aerobic exercise test (n = 5) was 79 W, representing 42% of mean power (averaged over the nine sprint tests) and 37% of P5. In contrast to P mean and P5, P max showed a significant association with peak aerobic power production and peak oxygen uptake. This may indicate that P max is an indicator of overall performance capacity, whereas P mean and P5 are much more sprint related. The methodology of wheelchair exercise testing requires further detailed study with respect to the physiology and bio-mechanics of arm work, the functionality of the subject population, and reliability and validity of procedures and techniques. Eventually this should lead to standardized and reliable testing procedures. Both a standardized sprint test and a standardized aerobic wheelchair performance test can serve as additional tools in the evaluation of physical performance in wheelchair sports medicine. Perhaps more important, they may also serve as clinical tools in the evaluation of the process of rehabilitation.

Influence of acute maximal exercise on lecithin: cholesterol acyltransferase activity in healthy adults of differing aerobic performance

To document the possible influence of a single episode of maximal aerobic stress on the serum lecithin:cholesterol acyltransferase (LCAT) activity in subjects with differing histories of training, two groups of healthy male adults [controls (C), n = 18, 28.6 years, SD 5.2, 50.1 ml.kg-1.min-1 maximal O2 uptake (VO2max), SD 5.3; endurance trained athletes (T), n = 18, 31.4 years, SD 8.8, 65.0 ml.kg-1.min-1 VO2max, SD 2.8] were examined in a maximal aerobic stress test. In addition to the routine assessment of lipid status, LCAT activity was measured immediately before and after exercise. At rest nearly identical LCAT activity values were found in both groups: C 64.4 nmol.ml-1.h-1, SD 16.7 vs T 65.0 nmol.ml-1.h-1, SD 20.9. The post-exercise LCAT values induced by the maximal stress test increased significantly to (C) 95.7 nmol.ml-1.h-1, SD 23.5, +48.6%, P less than 0.001; (T) 83.5 nmol.ml-1.h-1, SD 24.3, +29.1%, P less than 0.01. Neither the pre nor the postexercise individual LCAT activity values showed any significant correlation to the corresponding data on physical performance.

Plasma testosterone during treadmill exercise.

Five male volunteers performed 20 min of steady-state submaximal exercise on a motor-driven treadmill at five intensities (30, 45, 60, 75, and 90% VO2 max) as well as several maximal aerobic capacity tests. Peripheral venous plasma testosterone concentrations increased above resting values in proportion to exercise intensity. However, this increase in plasma testosterone concentration was virtually equal in magnitude to the decrease in plasma volume observed consequent to the exercise bouts, resulting in no change in total testosterone contents. There was an unexpected anticipatory elevation in resting preexercise control testosterone concentration and content with increasing work intensity. The possibility that testosterone has a direct role in the organism's response to whole-body exercise is questioned.