Metabolic responses to light arm and leg exercise when sitting

Summary Seven male subjects performed progressive exercises with a light work load on an upper limb or bicycle ergometer in the sitting position. At any comparable work load above zero, arm exercise induced higher oxygen uptake, ventilation, heart rate, oxygen pulse, respiratory rate and tidal volume than leg exercise. At similar levels of above 0.45 1 · min^–1, heart rate and ventilation were higher during arm exercise. A close linear relationship between carbon dioxide output and oxygen uptake was observed during both arm and leg exercises, the slope for arm work being steeper. The ventilatory equivalent for gradually decreased during both types of exercise. The ventilatory equivalent for remained constant (arm) while it rose (leg) to a peak at 9.8 W and then gradually decreased. Ventilation in relation to tidal volume had a linear relationship with leg exercise, but became curvilinear with arm exercise after tidal volume exceeded 1100ml. The observed differences in response between arm and leg exercises at a given work load appear to be influenced by differences in sympathetic outflow due to the greater level of static contraction of the relatively small muscle groups required by arm exercise.     

Effect of training on the rating of perceived exertion at the ventilatory threshold

Summary The purpose of this study was to determine the effect of training on the rating of perceived exertion (RPE) at the ventilatory threshold. College students were assigned to either training (n=17) or control (n=10) groups. Trainers completed 18 interval training sessions (five × 5 min cycling at 90–100% ) and 8 continuous training sessions (40 min running or cycling) in 6 weeks. Pre- and post-training, cardiorespiratory, metabolic, and perceptual variables were measured at the ventilatory threshold during graded exercise tests on a cycle ergometer. Ventilatory threshold was that point above which increased abruptly relative to work rate. Post-training means of trained and control subjects were compared using analysis of covariance, with pre-training values as covariates. Following training, the adjusted means for the trained subjects were significantly greater (p<0.05) than for controls for (6%), and for work rate (20%), (23%), and % (13%) at the ventilatory threshold. However, adjusted means for RPE at the ventilatory threshold were not significantly different (2%). Both before and after training, exercise at the ventilatory threshold was perceived as somewhat hard to hard (RPE=13–15) by both groups. The relationship between RPE and % was altered by training, with trained subjects having a lower RPE at a given % . It is concluded that RPE at the ventilatory threshold is not affected by training, despite that after training the ventilatory threshold occurs at a higher work rate and is associated with higher absolute and relative metabolic and cardiorespiratory demands.     

Physical work capacity in dynamic exercise with differing muscle masses in healthy young and older men

Ten young (aged 23–30 years) and nine older (aged 54–59 years) healthy men with similar estimated limb muscle volumes performed, in random order, three different types of ergometer exercise tests (one-arm cranking, two-arm cranking, and two-leg cycling) up to the maximal level. Values for work load (WL), peak oxygen consumption , peak heart rate (HR), peak ventilation , respiratory gas exchange ratio (R), recovery blood lactate concentration [La^–], and rating of perceived exertion (RPE) were compared between the age-groups in the given exercise modes. No significant age-related differences in WL, peak , peak HR, R, [La^–], or RPE were found in one-arm or two-arm cranking. During one-arm cranking the mean peak was 1.65 (SD 0.26)1 · min^–1 among the young men and 1.63 (SD 0.10)1 · min^–1 among the older men. Corresponding mean peak during two-arm cranking was 2.19 (SD 0.32)1 · min-1 and 2.09 (SD 0.18)1 · min^–1, respectively. During one-arm cranking peak was higher (P < 0.05) among the older men compared to the young men. During two-leg cycling the young men showed higher values in WL (P < 0.001), peak (P < 0.001), and peak HR (P < 0.001). The mean peak was 3.54 (SD 0.24)1 · min^–1 among the young men and 3.02 (SD 0.20)1 · min^–1 among the older men. Corresponding mean peak HR was 182 (SD 5) beats · min^–1 and 170 (SD 8) beats · min^–1, respectively. During two-leg cycling, peak , R, [La^–], and RPE did not differ between the two age-groups. In summary, the older men with similar sizes of estimated arm and leg muscle volumes as the young men had a reduced physical work capacity in two-leg cycling. In one-arm or two-arm cranking, no significant difference in work capacity was found between the age-groups. These results indicate, that in healthy men, age, at least up to the 6th decade of life, is not necessarily associated with a decline in physical work capacity in exercises using relatively small muscle groups, in which the limiting factors are more peripheral than central.     

Effects of previous exercise on the ventilatory determination of the aerobic threshold

Summary To study the effects of previous submaximal exercise on the ventilatory determination of the Aerobic Threshold (AeT), 16 men were subjected to three maximal exercise tests (standard test = ST, retest = RT, and test with previous exercise = TPE) on a cycle ergometer. The protocol for the three tests consisted of 3 min pedalling against 25 W, followed by increments of 25 W every minute until volitional fatigue. TPE was preceded by 10 min cycling at a power output corresponding to the AeT as determined in ST, followed by a recovery period pedalling against 25 W until returned to values consistent with the initial response to 25 W. AeT was determined from the gas exchange curves (ventilatory equivalent for O₂, fraction of expired O₂, excess of , ventilation, and respiratory gas exchange ratio) printed every 30 s. The results showed good ST×RT reliability (r=0.89). TPE showed significantly higher AeT values (2.548±0.44 l·min^–1) when compared with ST (2.049±0.33 l·min^–1) and RT (2.083±0.30 l·min^–1). There were no significant differences for the sub-threshold respiratory gas exchange ratios among the trials. The sub-threshold response showed significantly higher values for TPE at power outputs above 50 W. It was concluded that the performance of previous exercise can increase the value for the ventilatory determination of the AeT due to a faster sub-threshold response.Supported by fellowship number 3660/80-3, CAPES, Brazil     

Acute altitude exposure and altered acid-base states

Summary This study examined the influence of acute altitude (AL) exposure alone or in combination with metabolic acid-base manipulations on the exercise ventilatory and blood lactate responses. Four subjects performed a 4 min, 30 W incremental test to exhaustion at ground level (GL) and a 4 min, 20 W incremental test during three acute exposures to a simulated altitude of 4200 m; (i) normal (NAL), (ii) following 0.2 g·kg^–1 ingestion of sodium bicarbonate (BAL), and (iii) following 0.5 g·day^–1 ingestion of acetazolamide for 2 days prior to exposure (AAL). increased progressively throughout the incremental tests at AL and the minimum value was not related to a change in the blood lactate response. In contrast, the decreased initially to reach a minimum value at the same power output for each altitude trial and was related to a lactate threshold defined by a log-log transformation (r=0.78). This transformation of the blood lactate data was not influenced by the altered acid-base states. The relative exercise intensity corresponding to both a lactate of 1 mM and an absolute lactate of 4 mM was significantly increased during the AAL (79.9±12.9 and 93.9±13.7% , respectively) compared with NAL (59.1±5.5 and 78.0±5.8% , respectively). These data suggest that strong relationships exist between the ventilatory and blood lactate response during AL exposure and altered acid-base states. Further, it is concluded that, unless the acid-base status is known, the use of an absolute or lactate value to compare submaximal exercise should be interpreted with caution.     

The effects of dietary manipulation upon the respiratory exchange ratio as a predictor of maximum oxygen uptake during fixed term maximal incremental exercise in man

Summary This study examined the effects of dietary manipulation upon the respiratory exchange ratio ( ) as a predictor of maximum oxygen uptake ( ). Seven healthy males performed fixed term maximal incremental treadmill exercise after an overnight fast on three separate occasions. The first test took place after the subjects had consumed their normal mixed diet (45±5% carbohydrate (CHO)) for a period of three days. This test protocol was then repeated after three days of a low CHO diet (3±2% CHO), and again after three days of a high CHO diet (61±5% CHO). Respiratory gases were continuously monitored during each test using an online system. No significant changes in mean exercise oxygen uptake ( ), or maximum functional heart rate (FHR_max) were found between tests. Mean exercise carbon dioxide output ( ) and R were significantly lower than normal after the low CHO diet (bothp<0.001) and significantly higher than normal after the high CHO diet (bothp<0.05). Moreover, compared with the normal CHO diet, the R-time relationship during exercise was at all times significantly (p<0.001) shifted to the right after the low CHO diet, and shifted to the left, being significantly so (p<0.05) over the final 5 min of exercise, after the high CHO diet. As a result, predictions of based on the R-time relationship were similar to recorded after the normal CHO dietary condition (-1.5±1.9%), but higher after the low CHO diet (+14.8±3.9%,p<0.001) and lower after the high CHO diet (–7.0±4.5%,p<0.01). These results indicate that dietary manipulation can significantly affect respiratory gas exchanges during fixed term maximal incremental exercise, and by doing so can significantly influence predictions of based on R.     

Predictors of sweat loss in man during prolonged exercise

Summary Nineteen healthy male subjects, differing in training status and (52±1 ml · min^–1 · kg^–1, mean ±SEM; 43–64 ml · min^–1 · kg^–1, range), exercised for 1 h at an absolute workload of 192±8 W (140–265 W); this was equivalent to 70±1% (66–74%). Each exercise test was performed on an electrically braked cycle ergometer at a constant ambient temperature (22.5±0.0° C) and relative humidity (85±0%). Nude body weight was recorded prior to and after each exercise test. Absolute sweat loss (body weight loss corrected for respiratory weight loss) during each test was 910±82 g (426–1665 g); this was equivalent to 1.3±0.1% (0.7–2.2%) of pre-exercise body weight (relative sweat loss). Weighted mean skin temperature and rectal temperature increased after 5 min of exercise from 30.5±0.3° C and 37.2±0.1° C respectively to 32.5±0.2° C and 38.8±0.1° C respectively, recorded immediately prior to the end of exercise. Bivariate linear regression and Pearson's correlation demonstrated absolute sweat loss was related to (r=0.72,p<0.001), absolute exercise workload (r=0.66,p<0.01), body surface area (r=0.62,p<0.01), weight (r=0.60,p<0.01) and height (r=0.53,p<0.05). Relative sweat loss was related to (r=0.77,p<0.001) and absolute exercise workload (r=0.59,p<0.01). There was no relationship between sweat loss (absolute or relative) and heart rate, skin temperature or rectal temperature. In addition, there was no relationship between rectal temperature or absolute exercise workload or . Stepwise multiple linear regression indicated to be the most important predictor of absolute (r=0.72,F=18.27,p<0.001) and relative (r=0.77,F=24.58,p<0.001) sweat loss in man during prolonged exercise.     

The effects of high intensity training upon respiratory gas exchanges during fixed term maximal incremental exercise in man

Summary The response of respiratory gas exchanges to a 6 week high intensity training program was examined in 5 healthy males during fixed term maximal incremental treadmill exercise. Training was performed 3 d·wk^–1 and consisted of a progressive series of repeated 15 sec and 30 sec maximal runs, and weight training exercises for the leg extensor muscles. Respiratory gases during the tests were continuously monitored using an on-line system. Muscle biopsy samples were obtained from the m. vastus lateralis before and after training for histochemical determination of fibre distribution based on myosin ATP-ase activity, and fibre cross-sectional area based on NADH-Tetrazolium Reductase activity. Training significantly increased the proportion of type IIa fibres (+5.9±2.0%,p<0.001) and decreased type I fibres (–6.3±2.0%,p<0.001), the distribution of type IIb fibres remained unchanged (+0.4±0.9%). Muscle cross-sectional area also showed a significant increase after training in type I (+ 318±215 m²,p<0.05), IIa (+652±207 m²,p<0.001) and IIb (+773±196 m²,p< 0.001) fibres. During fixed term maximal incremental exercise the mean carbon dioxide output ( ) and mean respiratory exchange ratio ( ) were significantly increased (p<0.01) after training. The R-time relationship was at all times shifted to the left after training, being significantly (p<0.01) so over the final five min of exercise. No changes in mean exercise oxygen uptake ( ), maximum oxygen uptake ( ) and maximum heart rate (FHR_max) were observed between tests. These results indicate that high intensity training can significantly affect respiratory exchange during fixed term progressive exercise.     

The effect of one-legged sprint training on intramuscular pH and nonbicarbonate buffering capacity

Summary To determine the effect of one-legged sprint training on muscle pH and nonbicarbonate buffering capacity (BC), 9 subjects completed 15 to 20 intervals at 90 RPM, 4 days a week for 7 weeks on a bicycle ergometer adapted for one-legged pedaling. Needle biopsies from the vastus lateralis and blood samples from an antecubital vein were taken at rest and twice during recovery (1 and 4 minutes) from a 60 s one-legged maximal power test on a cycle ergometer. pH one minute after exercise in both the trained and untrained legs following the training period was not different but both were higher than before training. BC increased from 49.9 to 57.8 mol HCl×g^–1×pH^–1 after training (p<0.05). Blood lactate levels after exercise were significantly higher for the trained leg when compared to the untrained leg after sprint training. Peak and average power output on the 60 s power test increased significantly after training. One-legged aerobic power ( ) significantly increased in the untrained and trained legs. Two-legged also improved significantly after training. These data suggest that nonbicarbonate buffering capacity and power output can be enhanced with one-legged sprint training. Also, small but significant improvements in were also observed.     

Energy cost of arm stroke,leg kick,and the whole stroke in competitive swimming styles

In male elite swimmers \(\dot V_{{\text{O}}_{\text{2}} } \) at a given velocity in freestyle and backstroke was on average 1 to 2 l x min^?1 lower as compared with breaststroke and butterfly. Except for breaststroke, swimming with arm strokes only demanded a lower \(\dot V_{{\text{O}}_{\text{2}} } \) at a given submaximal velocity than the whole stroke. In freestyle and backstroke the submaximal \(\dot V_{{\text{O}}_{\text{2}} } \) of leg kick at a given velocity was clearly higher than the whole stroke. The highest velocity during maximal swimming was always attained with the whole stroke, and the lowest with the leg kick, except for breast stroke, where the leg kick was most powerful. At a given submaximal \(\dot V_{{\text{O}}_{\text{2}} } \) , heart rate and \(\dot V_{\text{E}} :\dot V_{{\text{O}}_{\text{2}} } \) tended to be higher during swimming with arm strokes only as compared with the whole stroke. Highest values for \(\dot V_{{\text{O}}_{\text{2}} } \) , heart rate and blood lactate during maximal exercise were almost always attained when swimming the whole stroke, and lowest when swimming with arm strokes only. At higher velocities body drag was 0.5 to 0.9 kp lower when arms or legs were supported by a cork plate as compared with body drag without support.     

Factors which alter the relationship between ventilation and carbon dioxide production during exercise in normal subjects

The slope of the linear relationship between ventilation and carbon dioxide production has been thought to indicate that is one of the major stimuli to . A group of 15 normal subjects undertook different incremental treadmill exercise protocols to explore the relationship between and . An incremental protocol using 1 instead of 3-min stages of exercise resulted in an increase in the to ratio [26.84 (SEM 1.23) vs 31.08 (SEM 1.36) (P < 0.008) for the first stage, 25.24 (SEM 0.86) vs 27.83 (SEM 0.91) (P < 0.005) for the second stage and 23.90 (SEM 0.86) vs 26.34 (SEM 0.81) (P = 0.001) for the third stage]. Voluntary hyperventilation to double the control level of during exercise resulted in an increase in the to slope [from 21.3 (SEM 0.71) for the control run to 35.1 (SEM 1.2) for the hyperventilation run (P < 0.001)]. Prolonged hyperventilation (5 min) during exercise at stage 2 of the Bruce protocol resulted in a continuted elevation of and the slope. A steady state of and metabolic gas exchange can only be said to have been present after at least 3 min of exercise. Voluntary hyperventilation increased the slope of the relationship between and . End-tidal carbon dioxide fell, but remained within the normal range. These results would suggest that a non-carbon dioxide factor may have been responsible for the increase we found in during exercise, and that factors other than increased dead space ventilation can cause an increased ventilation to slope, such as that seen in some pathophysiological conditions, such as chronic heart failure.     

Ramp work tests with three different beta-blockers in normal human subjects

Summary The effects of-blockade on the responses of oxygen uptake ( ), heart rate (HR) and blood lactate (La^–) were examined during ramp cycle ergometer tests (50 W·min^–1 ramp slope) in 8 healthy male volunteers. Each subject took placebo, or one of four different doses of three different-blockers (propranolol, metoprolol or oxprenolol) 2 h prior to each test for a total of 15 exercise tests. ( ) was measured breath-by-breath, HR was sampled once per breath, and La^– was obtained every minute. Linear regression analysis was applied to and HR data to obtain the kinetic parameter total lag time (TLT) and a slope value. La^– was analyzed by a continuous exponential model with the lactate slope index (LSI) being derived from the individual response curves. Submaximal exercise HR was significantly depressed at the baseline as well as during the ramp tests by-blockade. TLT for HR was significantly affected by-blockade, with a dose dependent shift from a placebo value of 16 to 26 s with placebo to a value of -40 to -60 s at the highest dose. Slope of HR was significantly depressed relative to placebo. kinetics assessed by TLT were not significantly affected by-blockade. This slope of the vs work rate relationship was significantly less than placebo only at the highest dose of-blocker. The LSI was not significantly affected by-blockade. In contrast with the clear impairment of HR response to exercise during-blockade, both the and La^– responses appear to be relatively unaffected by-blockade during ramp exercise tests. However, the significant change in slope of the vs work rate relationship at the highest dose level indicates that the oxygen transport system is in fact impaired by-blockade. It is concluded that the ramp exercise test is not a sensitive means of detecting changes in oxygen transport kinetics during exercise with-blockade. Further, there were no differences between the three-blocking drugs.Supported by the Heart and Stroke Foundation of Ontario, and the Natural Sciences and Engineering Research Council of Canada     

Are indices of free radical damage related to exercise intensity

Summary The possibility that plasma levels of malonaldehyde (MDA) are altered by exercise has been examined. The presence of MDA has been recognized to reflect peroxidation of lipids resulting from reactions with free radicals. Maximal exercise, eliciting 100% of maximal oxygen consumption ( ) resulted in a 26% increase in plasma MDA (P<0.005). Short periods of intermittent exercise, the intensity of which was varied, indicated a correlation between lactate and MDA (r ²=0.51) (p<0.001). Blood lactate concentrations increased throughout this exercise regimen. A significant decrease (10.3%) in plasma MDA occurred at 40% . At 70% plasma MDA was still below resting values, however the trend to an increase in MDA with exercise intensity was evident. At exhaustion, plasma MDA and lactate were significantly greater than at rest. These results suggest, that exhaustive maximal exercise induces free radical generation while short periods of submaximal exercise (i.e. <70% ) may inhibit it and lipid peroxidation.     

Effect of glucose polymer diet supplement on responses to prolonged successive swimming,cycling and running

Summary Fifteen male endurance athletes were studied to determine the effect of a glucose polymer (GP) diet supplement on physiological and perceptual responses to successive swimming, cycling and running exercise. Thirty min of swimming, cycling and running at 70% , followed by a run to exhaustion at 90% was performed after one week of training under two dietary conditions: 1) GP (230 g of GP consumed daily) and 2) placebo (P, saccharin-sweetened supplement consumed daily). During GP, daily carbohydrate (CHO) intake was higher (p<0.05) by 173 g or 14% of energy intake than during P, but total energy intake was not significantly different. During 90 min of exercise, CHO utilization and blood glucose were significantly higher under GP than P by an average of 20.2% and 14.5%, respectively, but heart rate, ventilation, oxygen uptake, ratings of perceived exertion, and plasma lactate were not different. Run time to exhaustion at 90% was significantly longer by 1.2 min (23%) under GP. The results suggest that a GP diet supplement may be of value during endurance exercise by increasing the availability of CHO.     

The energy cost of level cross-country skiing and the effect of the friction of the ski

Summary Oxygen consumption [( ) in ml·kg^–1·min^–1], blood lactate concentration ([La] in mM) and dynamic friction of the skis on snow [(F) inN] were measured in six athletes skiing on a level track at different speeds [(v) in m·min^–1] and using different methods of propulsion. The increased withv andF, the latter depending mostly on snow temperature, as did [La]. The was very much affected by the skiing technique. Multiple regression equations gave the following results: with diagonal stride (DS), =–23.09+0.189v+0.62N; with double pole (DP), =–30.95+0.192v+0.51N; and with the new skating technique (S), =–32.63 +0.171+0.68N. In terms of DS is the most expensive technique, while S is the least expensive; however, asF increases, S, at the highest speed, tends to cost as much as DP. At speeds from 18 to 22 km·h^–1, the speeds measured in the competitions, theF for DS and DP can represent from 10% to 50% of the energy expenditure, withF ranging from 10 to 60N; with S this range increases to 20%–70%. This seems to depend on the interface between the skis and the snow and on the different ways the poles are used.     

Respiratory frequency and the oxygen cost of exercise

Summary Although many studies indicate that the spontaneous breathing frequency minimizes breathing work, the consequences of this for exercise energetics have never been investigated. To see if the spontaneous exercise breathing frequency minimizes oxygen uptake, we compared during treadmill walking (2/3 max) at several alternative frequencies. The alternative frequencies ranged from the lowest sustainable to a frequency twice the spontaneous value. All eight subjects adjusted tidal volume to comfort. Exercise oxygen uptake was constant, independent of breathing frequency. At the same time, minute ventilation rose to be 65% greater at the highest frequency than at the lowest (P<0.01). We then reproduced the various exercise frequencies, tidal volumes, and ventilations during seated isocapnic hyperpnea to measure with locomotory muscles at rest. Once again, oxygen uptake was constant, independent of breathing frequency. We conclude that the spontaneous exercise breathing frequency fails to minimize during either exercise or resting reproduction of exercise ventilation.Supported in part by NIH Grant HL 26351     

Gastric emptying during walking and running: effects of varied exercise intensity

Summary Gastric emptying is increased during running (50%–70% maximal aerobic uptake, as compared to rest. Whether this increase varies as a function of mode (i. e. walking vs running) and intensity of treadmill exercise is unknown. To examine the gastric emptying characteristics of water during treadmill exercise performed over a wide range of intensities relative to resting conditions, 10 men ingested 400 ml of water prior to each of six 15 min exercise bouts or 15 min of seated rest. Three bouts of walking exercise (1.57 m · s^–1) were performed at increasing grades eliciting 28%, 41% or 56% of . On a seperate day, three bouts of running (2.68 ms^–1) exercise were performed at grades eliciting 57%, 65% or 75% of . Gastric emptying was increased during treadmill exercise at all intensities excluding 75% as compared to rest. Gastric emptying was similar for all intensities during walking and at 57% and 65% during running. However, running at 74% decreased the volume of original drink emptied as compared to all lower exercise intensities. Stomach secretions were markedly less during running as compared to walking and rest. These data demonstrate that gastric emptying is similarly increased during both moderate intensity (8%–65% ) walking or running exercise as compared to resting conditions. However, gastric emptying decreases during high intensity exercise. Increases in gastric emptying during moderate intensity treadmill exercise may be related to increases in intragastric pressure brought about by contractile activity of the abdominal muscles.     

Physical fitness of blind and sighted children

Summary Twenty-seven children (age 7–17 years) with varying degrees of blindness but with no other known disorder were assessed for physical fitness. Twenty-seven randomly selected children with normal eyesight were also assessed. Maximum oxygen uptake ( ) was measured directly during a progressive exercise test on a treadmill. There was a significant and substantial reduction in in totally blind children (mean ± standard deviation 35.0±7.5 ml · min^–1 · kg^–1) compared with normal children (45.9±6.6 ml · min^–1 · kg^–1). Partially sighted children had a significant but smaller reduction in . Fitness assessed by a step-test was significantly reduced in the visually impaired children, and skin-fold thickness was also significantly greater in totally blind children.The level of habitual physical activity for each child, as assessed by a questionnaire, correlated with (r=0.53,p<0.0001). Blind children were significantly less active than normal children, and the difference between mean for blind and normal children became non-significant when their different activity levels were taken into account. It is concluded that totally blind children are less fit than other children at least partly because of their lower level of habitual activity.     

The effects of arm crank training on the physiological responses to silbmaximal wheelchair ergometry

Summary The purpose of this investigation was to examine the cardiovascular and metabolic effects of a 5 wk arm crank (AC) training program on submaximal wheelchair (WC) ergometry in ablebodied women. The 6 subjects in the training group (TG) and 4 in the control group (CG) performed a 10 min WC exercise prior to and following the training period at a power output (PO) that elicited 70% of the pre-training peak oxygen uptake ( ). Steady state , heart rate (HR), cardiac output and stroke volume (V _s) were measured. Resting and post-exercise blood lactate concentrations (LA) were measured, the difference was recorded as net LA. The TG exercised on the AC 3 d · wk^–1 at a PO that elicited 85% of each subject's recorded peak HR. Each session consisted of four 4 min exercise bouts preceded by a 2 min warm-up and interspersed with 2 min rest periods. After training, the TG had a significantly (p<0.05) lower HR, largerV _s and lower LA in response to the WC exercise. and were not significantly altered. The results demonstrate that the AC exercise program used in this study produced a physiological training effect which was observed during submaximal WC exercise of an intensity frequently encountered during daily WC ambulation. It appears that short-term, moderate intensity AC training offers an adequate stimulus to reduce the stress imposed by wheelchair locomotion.     

The effects of cigarette smoking on maximal oxygen consumption and selected physiological responses of elite team sportsmen

Summary The acute and chronic effects of cigarette smoking on selected physiological responses were determined in seven well-trained non-smokers and seven well-trained habitual smokers. Non-smokers and smokers did not differ significantly with respect to maximal oxygen consumption ( ). The acute effect of smoking two cigarettes immediately prior to a graded exercise stress test on a treadmill ergometer did not significantly alter the of either group. However, the time taken for non-smokers to reach exhaustion decreased significantly (F=5.381, P<0.05) by a mean of 0.64 min. Smokers recorded lower scores for forced vital capacity (FVC) and forced expiratory volume in the 1st s exhalation (FEV₁) than non-smokers. Only the mean FVC of smokers recorded 5 min post-exercise was significantly altered by pre-exercise smoking. No differences were found between the resting heart rates (HR) of non-smokers and smokers. Smoking two cigarettes significantly (F=44.720, P<0.01) increased the mean resting HR of smokers and non-smokers by 15.8 beats·min^–1 and 15.6 beats·min^–1 respectively. No alteration to the exercise HR of either group was found under smoking conditions of the tests.