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Objectives: Rowers who entrain breathing frequency to stroke rate do so in either a 1:1 or 2:1 pattern. The purpose of this study was to investigate the performance and physiological difference that occurs between the practice of these two patterns of breathing. Methods: Fifteen novice female rowers (age =19.7 ± 1.6 yr.; body mass = 70.9 ±6.3 kg; height = 174.4 ±4.4 cm) were randomly assigned to complete a 2000 meter rowing ergometer test alternatively using each breathing pattern one week apart. Expired gases and breathing frequencies were measured using a Medical Graphics CPX‐D metabolic system. Heart rate (fc) was recorded using direct lead ECG. Stroke rate was obtained from the Concept II Ergometer. Results: Repeated measures MANOVA determined that when the breathing frequency was 2 breaths per stroke (2:1 versus 1:1), the time to complete the test was significantly shorter (490 ± 24.8 vs. 514 ± 11.3 s, p ≤ 0.05) and power output was greater (203.4 ± 21.5 vs. 184.5 ± 20.4 W, p ≤ 0.05). Oxygen uptake d...

Background—Pulmonary diVusing capacity for carbon monoxide (Dlco), alveolar capillary membrane diVusing capacity (Dm), and pulmonary capillary blood volume (Vc) are all significantly reduced after exercise. Objective—To investigate whether measurement position aVects this impaired gas transfer. Methods—Before and one, two, and four hours after incremental cycle ergometer exercise to fatigue, single breath Dlco, Dm, and Vc measurements were obtained in 10 healthy men in a randomly assigned supine and upright seated position. Results—After exercise, Dlco, Dm, and Vc were significantly depressed compared with baseline in both positions.The supine position produced significantly higher values over time for Dlco (5.22 (0.13) v 4.66 (0.15) ml/min/mm Hg/l, p = 0.022) and Dm (6.78 (0.19) v 6.03 (0.19) ml/min/mm Hg/l, p = 0.016), but there was no significant position eVect for Vc. There was a similar pattern of change over time for Dlco, Dm, and Vc in the two positions. Conclusions—The change in Dlco after exercise appears to be primarily due to a decrease in Vc. Although the mechanism for the reduction in Vc cannot be determined from these data, passive relocation of blood to the periphery as the result of gravity can be discounted, suggesting that active vasoconstriction of the pulmonary vasculature and/or peripheral vasodilatation is occurring after exercise. (Br J Sports Med 2000;34:440‐444)

Healthy male endurance-trained cyclists [n = 11, age = 27.3 (3.9) years; mass = 73.0 (9.3) kg; height = 180.5 (6.9) cm; maximal oxygen consumption (\(\dot VO_{2max} \) = 71.1 (5.8) ml · kg−1 · min−1, mean ± (SD)] were recruited to assess the relationship between test protocol and the development of desaturation of arterial hemoglobin with oxygen, during incremental exercise tests to maximal aerobic capacity\((\dot VO_{2max} )\). All subjects demonstrated resting pulmonary function within normal limits [forced vital capacity (FVC) = 6.0 (0.9); forced expiratory volume (FEV1.0) = 4.9 (0.6); FEV1.0/FVC = 0.8 (0.1)] and completed three ramped\(\dot VO_{2max} \) tests (Mijnhardt KEM-3 electronically braked cycle ergometer) beginning at 0 W with increments of either 20, 30 or 40 W · min−1. All periods of testing were separated by a minimum of 72 h.\(\dot VO_{2max} \), peak minute ventilation\((\dot V_{Epeak} )\) (Medical Graphics, CPX-D), peak heart rate (ƒcpeak)), peak power output\((\dot W_{peak} )\), and minimum percentage arterial oxyhemoglobin saturation (%SaO2min) (Omeda Biox 3740 pulse oximeter) were determined. There were no significant differences (p > 0.05) in\((\dot W_{peak} )\) [191.5 (26.2), 196.0 (24.4), 194.3 (23.9) 1 · min−1] ƒcpeak [191.4 (7.0), 190.3 (5.5), 187.8 (5.9) beats · min−1],\(\dot VO_{2max} \) [5.0 (0.5), 5.1 (0.4), 5.1 (0.5) 1 · min−1] or %SaO2min [89.5 (1.5), 89.6 (1.3), 90.0 (2.3)] between protocols. The 20-W protocol [417 (27) W] demonstrated significantly lower\(\dot W_{peak} \) (P < 0.05) than the 30-W [434 (36) W] and 40-W [453 (38) W] protocols, indicating that peripheral fatigue may play an important factor in response to these tests. The results of this study demonstrate that arterial desaturation occurs as a result of intense exercise in highly trained athletes independent of the rate of attainment of\(\dot VO_{2max} \).

The purpose of this study was to describe the upper body exercise capabilities of youth with spina bifida, which would permit comparison of their abilities to norms. Forty-two children with spina bifida age 7 to 18 years were tested for maximal handgrip strength, anaerobic arm-crank power output, and peak arm-crank oxygen uptake. Analysis of variance was used to compare age, gender, and level of disability differences within the total sample. This analysis indicated no significant effect of level of disability on any of the upper body exercise capacity measures. Significant gender and age effects were noted for grip strength and anaerobic and aerobic capabilities. The sample exhibited handgrip strength comparable to that of nondisabled youth but low anaerobic power and peak oxygen uptake values. Some individual subjects, however, had “normal” values for all tests suggesting that a lower level of participation in regular physical activity rather than spina bifida per se may be responsible for the generally lower physical capacity found in the total sample.

Nine male elite wheelchair athletes performed a continuous progressive exercise test on a wheelchair ergometer to determine peak oxygen uptake. Three were paraplegic distance track competitors (SCI–TR), three were amputee distance track athletes (AMP–TR), and three were paraplegic basketball players (SCI–BB). Analysis of variance indicated a significant difference in the relative peak oxygen uptake between the groups, with the SCI–TR and AMP–TR groups having higher values than the SCI–BB group. No group differences were found in age, mass, oxygen uptake, ventilation, heart rate, ventilatory equivalent for oxygen, and oxygen pulse at maximal exercise. The absence of the mass of the lower extremities in the AMP–TR group has a significant effect on peak oxygen uptake relative to body mass, and relative peak oxygen uptake differences between individual SCI–TR and AMP–TR athletes did not appear to reflect performance differences in actual distance track events.

Due to the recent discovery of exercise-induced arterial hypoxemia (EIAH) in healthy active women with normal levels of peak oxygen uptake (V'(O(2)peak), this study examined the incidence of EIAH in prepubescent females. Nineteen healthy, active, prepubescent females (X +/- SD: age = 11.1 +/- 1.6 years; height = 145.8 +/- 9.1 cm; weight = 35.6 +/- 7.0 kg) performed a progressive maximal exercise test on an electronically braked cycle ergometer starting at 0 W and increasing power by 15 W. min(-1). During this test, expired gases, heart rate (HR), and percent arterial oxyhemoglobin saturation (%SaO(2)) were measured. Results for physiological variables at maximal exercise were as follows: V'(O(2)peak) = 43.7 +/- 7.0 ml x kg(-1) x min(-1); HR(max) = 199 +/- 5 beats x min(-1); %SaO(2) = 96.6 +/- 1.2%. For nearly all subjects, the %SaO(2) at maximal exercise was above levels that would reduce V'(O(2)peak). Therefore, in comparison to previous reports of EIAH in adult women with similar V'(O(2)peak), EIAH does not appear to occur in the prepubescent female population.

The primary aim of this study was to compare the physiological responses to prolonged treadmill (TM) and water immersion to the neck (WI) running at threshold intensity. Ten endurance runners performed TM and WI running VO2max tests. Subjects completed submaximal performance tests at ventilatory threshold (Tvent) intensities under TM and WI conditions and responses at 15 and 42 minutes examined. VO2 was lower in WI (p0.05) at maximal effort and Tvent. The Tvent VO2 intensities interpolated from the TM and WI VO2max tests were performed in both TM (i.e., TM@TM(tvent),TM@WI(tvent), corresponding to 77.6 and 71.3% respectively of TM VO2max) and WI conditions (i.e., WI@TM(tvent), WI@WI(tvent), corresponding to 85.5% and 78.2% respectively of WI VO2max). Each of the dependent variables was analyzed using a 3-way repeated measures ANOVA (2 conditions X 2 exercise intensities X 7 time points during exercise). VO2max values were significantly lower in the WI (52.4(5.1) ml.kg(-1) min(-1)) versus TM (59.7(6.5) ml.kg(-1) min(-1)) condition. VO2 during submaximal tests were similar during the TM and WI conditions. HR and [BLa] responses to exercise at and above WI(tvent) were similar during short-term exercise, but values tended to be lower during prolonged exercise in the WI condition. There were no statistical differences in VE responses in the 2 conditions, however as with HR and [BLa] an upward trend was noted with TM exercise over the 42 minute duration of the tests. RPE at WI(tvent) was similar for TM and WI exercise sessions, however, RPE at TM(tvent) was higher during WI compared to TM running. Cardiovascular drift was observed during prolonged TM but not WI running. Results suggest differences in metabolic responses to prolonged submaximal exercise in WI, however it can be used effectively for cross training.

The maximal aerobic power (VO2max) and maximal anaerobic capacity (AODmax) of 16 female rowers were compared to their peak aerobic power (VO2peak) and peak anaerobic capacity (AODpeak, respectively) during a simulated 2-km race on a rowing ergometer. Each subject completed three tests, which included a 2-min maximal effort bout to determine the AODmax, a series of four, 4-min submaximal stages with subsequent progression to VO2max and a simulated 2-km race. Aerobic power was determined using an open-circuit system, and the accumulated oxygen deficit method was used to calculate anaerobic capacities from recorded mechanical power on a rowing ergometer. The average VO2peak (3.58 l min(-1)), which usually occurred during the last minute of the race simulation, was not significantly different (P > 0.05) from the VO2max (3.55 l min(-1)). In addition, the rowers' AODmax (3.40 l) was not significantly different (P > 0.05) from their AODpeak (3.50 1). The average time taken for the rowers to complete the 2-km race simulation was 7.5 min, and the anaerobic system (AODpeak) accounted for 12% of the rowers' total energy production during the race.

The purpose of this study was to determine the effects of repeated heavy exercise on postexercise pulmonary diffusing capacity (DL) and the development of exercise induced arterial hypoxemia (EIH).13 endurance-trained, male athletes (age = 27+/-3 yr, height = 179.6+/-5.0 cm, weight = 71.8+/-6.9 kg, VO2max = 67.0+/-3.6 mL x kg(-1) x min(-1) performed two consecutive, continuous exercise tests on a cycle ergometer to VO2max, separated by 60 min of recovery. Arterial oxygen saturation (%SaO2) was measured via ear oximetry, and resting DL was measured and partitioned by the single-breath method, before exercise and 60 min after each exercise bout.No significant differences resulted in VO2max, VE, peak heart rate (HR), or breathing frequency between exercise bouts (P0.05). There was a small but significant decrease (454-446 W; P0.05) in peak power output in the second test. %SaO2 decreased from resting values during both exercise tasks, but there was no difference between the minimum saturation achieved in test 1 (91.4) or test 2 (91.6; P0.05). After the initial exercise bout, significant decreases (P0.05) occurred in DL (11%), membrane diffusing capacity (DM) (11%) and pulmonary capillary volume (VC) (10%). Further decreases occurred in DL (6%; P0.05), DM (2%; P0.05), and VC (10%; P0.05) after the second exercise bout.These observations question the meaning of post exercise measurements of pulmonary diffusion capacity, and its components, relative to pulmonary gas exchange and pulmonary fluid accumulation during exercise. The fact that there was no further change in %SaO2 after the second test suggests that if any interstitial edema developed, it was of no clinical significance; alternatively, the changes in DL(CO) may be related more to redistribution of blood than the development of pulmonary edema.

We investigated the time course of changes in post-exercise pulmonary diffusing capacity for carbon monoxide (DLCO), membrane diffusing capacity (DM), and pulmonary capillary blood volume (VC) in highly trained (HT), moderately trained (MT) and untrained (UT) male subjects (n = 8/group). Subjects were assigned to groups based on their aerobic capacity from a preliminary VO2max test (HT > or = 65, MT = 50-60, UT < or = 50 ml x kg(-1) x min(-1)). Resting (BASE) DLCO, DM and VC were obtained, then subjects cycled to fatigue at the highest workrate attained during the preliminary tests. Diffusion measurements were then made at 1, 2, 4, 6 and 24 h. DLCO was depressed at 1 h, lowest at 6 h and approached BASE values at 24 h in all groups. The DLCO change was paralleled by a change in VC. Alterations to VC were similar between groups except at 24 h where MT and HT subjects had returned to BASE while UT did not. DM was significantly lower than BASE at 1, 2, 4, and 6 h, and was similar between groups. The changes in DLCO post-exercise appear to be primarily due to a decrease in VC. Comparable diffusion decrements were observed in all subjects. The results of this study suggest that post-exercise alterations in DLCO, DM and VC are not related to aerobic capacity.

To compare aerobic and anaerobic fitness of a group of children w-th chronic arthritis with that of healthy controls, and to explore the relationship between physical fitness and other indices of health status in these children.Thirty-one children aged 8 to 17 years with chronic arthritis of varying type and severity and 16 physically healthy controls participated in the study. Using a cycle ergometer, aerobic fitness was assessed by measuring peak oxygen uptake achieved in a 15 s period during exercise to volitional fatigue. Anaerobic fitness was assessed by measuring peak power in the legs in a 5 s period and total work completed (Wingate test). Joint pain experienced over the week before testing and during testing was measured using a 10 cm visual analog scale. Self-esteem was measured using the Self Perception Profile for Children Questionnaire.There were no significant differences between mean peak O2 uptake or mean peak anaerobic power for patients and controls; however, the mean values for both controls and patients were significantly lower than reported values for healthy children. Peak O2 uptake controlled for age, sex, and sum of skinfolds was negatively associated with disease severity, measured by physician global assessment (p = 0.04), but peak power was not. Neither aerobic nor anaerobic fitness were associated with disease activity measured by physician global assessment or active joint count, or with disease duration. There was a tendency for children with active arthritis to experience less pain during fitness testing than over the previous week (p = 0.06). Testing did not seem to exacerbate joint symptoms. Self-ratings of athletic competence were significantly correlated with peak O2 uptake achieved for children with arthritis (r = 0.43, p = 0.02), but not for controls. Global self-esteem was moderately correlated with self-rated athletic competence in controls (r = 0.49, p = 0.09), but was not in children with arthritis.In this sample of children, most of whom had limited joint involvement, we failed to demonstrate significant group differences in fitness between patients and controls. Disease severity may be related to fitness levels, but psychosocial factors may perhaps be more important determinants of fitness. Children with arthritis seem to have realistic perceptions of their own physical capabilities, and even those children who are less fit and perceive themselves as having less athletic competence do not appear to have lowered self-esteem.

The purpose of this investigation was to quantify the difference in energy expenditure between traditional cycling handlebars and aero-bars during outdoor submaximal cycling. Eleven trained cyclists (age = 29.3 ± 1.9 years, weight = 69.4 ± 3.8 kg, VO2max = 58.1 ± 2.0 ml∙kg−1∙min−1) were randomly assigned a sequence of three hand positions: brake hoods (BH), drop-bars (DB), and aero-bars (AB). Subjects cycled at 30 km∙h−1 in one position for 5 minutes, then recovered until HR fell below 120 bpm. This was then repeated for the other hand positions. All cycling was completed on a standard racing bike fitted with aero-bars. Tire pressure was held constant for all trials. A portable telemetric system (Cosmed K-2) was used to measure VO2, VE and heart rate (HR) during the trials. No statistical differences were observed between AB and DB. Significant differences (p E = 66.1 ± 2.7 L∙min−1; HR = 152 ± 4 bpm; VO2 = 1.56 ±.15 L∙min−1) and AB (VE = 61.3 ± 2.8 L∙min−1; HR = 146 ± 4 bpm; VO2 = 1.31 ±.10 L∙min−1). AB provides an energy savings over the traditional BH cycling posture. Key words: aerodynamic handlebars, oxygen consumption, field testing, portable telemetric system

The ventilatory thresholds of 30 male wheelchair athletes were determined from their respiratory and metabolic responses to a continuously progressive exercise protocol to peak oxygen uptake on a wheelchair ergometer. The peak oxygen uptake (peak VO2), ventilatory threshold in 1 min-1 (VTL), and ventilatory threshold expressed as a percentage of peak VO2 (VT%) were measured for all subjects. Statistical analyses of selected subsamples were used to note sport and functional ability level differences in these variables. Analysis of peak VO2 by functional classification (old International Stoke Mandeville Games Federation system; classes 1A-5, plus an amputee class) indicated that paraplegic (classes 2-5) and the amputee class athletes (2.48 1 min-1) were higher than tetraplegic (classes 1A-1C) athletes (0.95 1 min-1). The paraplegic and amputee classes were combined for a comparison of peak VO2 by sport which showed that track athletes (2.80 1 min-1) were higher than basketball players (2.41 1 min-1) who were higher than athletes from other sports (1.88 1 min-1). The VTL analyses demonstrated differences similar to the peak VO2 analyses. The VT% analyses, however, showed no sport differences, but the tetraplegic athletes had higher VT% values (87%) than the paraplegic plus amputee group (69%).

The purpose of this study was to measure the wheelchair drag and maximal sprint performance abilities of wheelchair basketball players and to make comparisons between male and female players. A group of nine male and eight female wheelchair basketball players attending a national training camp consented to serve as subjects. Each subject completed six coast-down trials at speeds from a walking pace (1 to 1.5 m/s) to maximal for determining wheelchair drag and then performed four maximal sprint trials from a stationary start over the length (35 m) of the gymnasium floor. A portable computer that recorded the time to the nearest 0.001 second of each half revolution of a rear wheel was attached to the wheelchair of each subject. The drag force during the coast-down trials and the power output during the sprint trials were determined from the recorded data. Differences between the genders in a number of subject and trial variables were evaluated by t-tests using the 0.05 level of significance. There were no significant differences between the means of the male and female groups in age (27 vs. 28 yrs), wheelchair mass (12.0 vs. 11.61 kg), or regression predicted drag forces at speeds of 2 m/s (5.3 vs. 5.5 N) and 5 m/s (16.7 vs. 13.5 N). The male subjects were significantly heavier (78.3 vs. 59.1 kg) and had a higher tire pressure (123 vs. 94 psi). In the sprint trial results, the males exhibited a significantly higher maximal speed (4.75 vs. 4.08 m/s), higher peak acceleration (1.32 vs. 1.03 m/s/s), and a higher peak power output (530 vs. 264 w).

A single subject performed 36 coast-down trials on a hardwood floor in a sport model wheelchair with velocity ranging from 1.28 to 5.31 m/s (4.6 to 19.1 km/h). A portable computer attached to the wheelchair was used to record the time to the nearest 0.001-second of each half-revolution of a rear wheel. The deceleration during each trial was determined with an average coefficient of variation of 2.6 percent from linear regression of velocity versus time values. A significant relationship (r = 0.97) between deceleration and the square of the velocity was noted in an analysis of the values from the 36 trials. Total drag force and power was calculated as a function of wheelchair velocity from this relationship, indicating that the power output needed to propel the wheelchair increased as a function of the velocity cubed. It is speculated that this noted exponential increase in the energy cost of wheelchair propulsion at higher speeds was due mainly to an increase in air drag.

Eight international caliber wheelchair male athletes (3 basketball, 5 distance track) performed an all-out propulsion effort from a standing start for 10 seconds on a wheelchair ergometer. Comparisons between the basketball and track athletes on linear wheelchair and push rim velocity during the first 3 pushes and the peak value indicated that the basketball players had a significantly (p less than .05) higher push rim velocity throughout the effort and a higher wheelchair velocity only at the end of the first push. The track athletes attained a significantly higher peak wheelchair velocity. Graphical comparison of the best individual basketball and track athletes' performances indicated that the track athletes caught up to the basketball players after about 3.7 seconds or 12 meters and travelled 49 meters in the 10 seconds, compared to 37 meters for the basketball players. Differences in push rim and wheel diameter are considered the major factor in the noted differences in propulsion kinematics of basketball and track wheelchairs.

The purpose of this study was to assess the relationship of the heart rate deflection point (HRDP) to the ventilatory threshold (VT) in trained cyclists. Twenty-one endurance-trained cyclists (mean +/- SD: Vo(2)max = 67.6 +/- 4.7 ml x kg x min(-1)) completed a maximal cycle ergometer test of volitional fatigue using a ramped protocol. Ventilatory variables (Ve, Vo(2), Vco(2)) and power were measured online with averages reported every 20 seconds. Heart rate (HR) was recorded every 20 seconds using a Polar monitor. VT was calculated using the excess CO(2) elimination curve. The first derivative of a logistic growth curve fit to the HR-power data produced the HRDP. No significant differences (p > 0.01) existed between HR values at HRDP (171.7 +/- 9.6 b x min(-1)) and VT (169.8 +/- 9.9 b x min(-1)) or between Vo(2) values at HRDP (53.6 +/- 4.2 ml x kg x min(-1)) and VT (52.2 +/- 4.8 ml x kg x min(-1)). But power values at HRDP (318.7 +/- 30.7 W) were significantly different (p < 0.01) from those at VT (334.8 +/- 36.7 W). There were significant relationships between HRDP and VT for the physiological variables of HR (r = 0.92, p < 0.001), Vo(2) (r = 0.72, p < 0.001), and power (r = 0.77, p < 0.001). These findings indicate that HR and Vo(2) at HRDP are not significantly different from the values at VT in trained cyclists. HR values derived from HRDP may be used to set parameters for training intensity. Variability in the speed/power-HRDP relationship across detrained/trained states may be used to evaluate training programs.

A sport model wheelchair instrumented with a portable computer and a switch activated with each half revolution of a rear wheel was used to record serial time and distance data on two subjects (1 male, 1 female) during a portion of a basketball game. These and two additional subjects (1 male, 1 female) also completed a series of coast down and maximal sprint trials on the basketball court. The drag force while coasting was positively related to the mass of the subject, and the male subjects had a higher maximal speed, acceleration, force, and power output in the sprint trials. During the wheelchair basketball game, it was estimated that 64% of the time was spent in propulsive action and 36% in braking activity. Projections for a complete 40 minute game indicated that both subjects would travel about 5 km at an average speed of 2 m.s-1 and attain a peak speed of 4 m.s-1. Plots of speed and power vs time showed the intermittent nature of playing wheelchair basketball. The greater amount of propulsive work (52.6 vs 37.5 kJ) and braking ("negative") work (43.9 vs 30.8 kJ) in a game for the male subject can be related to the male's higher body mass and wheelchair drag force.

A single subject performed 36 coast-down trials on a hardwood floor in a sport model wheelchair with velocity ranging from 1.28 to 5.31 m/s (4.6 to 19.1 km/h). A portable computer attached to the wheelchair was used to record the time to the nearest 0.001-second of each half-revolution of a rear wheel. The deceleration during each trial was determined with an average coefficient of variation of 2.6 percent from linear regression of velocity versus time values. A significant relationship (r = 0.97) between deceleration and the square of the velocity was noted in an analysis of the values from the 36 trials. Total drag force and power was calculated as a function of wheelchair velocity from this relationship, indicating that the power output needed to propel the wheelchair increased as a function of the velocity cubed. It is speculated that this noted exponential increase in the energy cost of wheelchair propulsion at higher speeds was due mainly to an increase in air drag.

The relative stress of participation in wheelchair basketball, volleyball, tennis, and racquetball were determined by monitoring the heart rates of wheelchair athletes. Heart rates were recorded for 5 seconds every 30 seconds during monitoring sessions of 10 min or longer under game or practice conditions. Subjects were volunteer paraplegic athletes with lesions below T5 or with equivalent disability according to an international sport classification system. Average heart rates were 89 beats/min for tennis 'practice', 96 for racquetball 'practice' 107 for volleyball 'practice', 114 for volleyball 'game', 127 for tennis 'game', 129 for basketball 'practice', 135 for racquetball 'game', and 149 for basketball 'game' conditions. The percentage of time when heart rates were above 140 beats/min, followed the same pattern as the average heart rates and ranged from 0 to 62%.