摘要:

Changes in myocardial oxygen supply were evaluated in 19 patients following coronary by-pass surgery (CBS) for angina pectoris (ΔP). A symptom limited maximal functional graded exercise test (G$T) was performed before and 2–19 ($ 7.5) months following CBS. After surgery the patients were urged to resume full activity and were individually managed in a 10-week “at home” exercise program. Increases were demonstrated for predicted oxygen uptake and work load (p<.002), and rate pressure product (p<.02) following CBS, suggesting increased myocardial blood flow. Terminal heart rate showed no significant increase. Of 16 patients exhibiting ST segment depression (≥.1 mV) with AP during G$T before surgery, 10 cases experienced total relief of both of these signs after surgery. A correlation between the pre-operative number of occluded coronary arteries (>50%) and the degree of exercise induced ST segment depression revealed no significant trend. Additionally, no significant relationship was found between post-operative G$T results and the number of by-pass grafts performed on each patient. This study supports the premise that the effectiveness of CBS, in improving functional capacity, can be objectively evaluated by a non-invasive functional GXT.

ISSN:0025-7990    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

The effect of exercise on the severity of isoproterenol-induced myocardial infarction was studied in male rats. Ninety-three rats were randomly divided into three groups. The exercise-isoproterenol (E-I) and exercise control (EC) groups exercised daily for thirty days on a treadmill at 1 mph, 2% grade while animals of the sedentary-isoproterenol (S-I) group remained sedentary. Eight animals were assigned to the sedentary control (SC) group which remained sedentary throughout the experimental period. Forty-eight hours after the final exercise period, S-I and E-I animals received a single subcutaneous injection of isoproterenol (250 mg/kg body weight). Animals of the S-I group exhibited significantly (Pp < 0.05) greater mortality from the effects of isoproterenol than animals of the E-I group. Serum CPK activity for E-I animals was significantly (p < 0.05) greater than for animals in the S-I and EC groups twenty hours following isoproterenol injection. No statistically significant differences were observed between the two isoproterenol treated groups for severity of the induced lesions, changes in heart weight, or heart weight to body weight ratios. The results indicated that exercise reduced the mortality associated with the effects of large dosages of isoproterenol but had little effect on the severity of the infarction.

ISSN:0025-7990    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

It is often recommended that during exercise the exerciser monitor his heart rate so that it can be maintained at a rate rapid enough to promote aerobic conditioning but not so rapid as to be dangerous. Various authorities recommend that the heart rate be determined by placing the fingers along the side of the neck, to palpate the carotid artery. In the author's laboratory, it has been observed that carotid artery palpation usually causes cardiac slowing and occasionally produces cardiac abnormalities. To further test this observation, 117 subjects were studied. Heart rate was monitored during rest, during exercise, and immediately following exercise while the subject palpated at three locations, the carotid artery, the radial artery, and the temporal artery. A continuous baseline electrocardiogram recording was made prior to, during, and after palpation. Immediately following carotid artery palpation, significant heart rate changes occurred in 90.6% of the subjects and various morphologic electrocardiographic abnormalities were seen in 17.1% of the subjects. The major abnormalities were P-wave changes. No heart rate changes or cardiac abnormalities were observed during radial artery or temporal artery palpation.

ISSN:0025-7990    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

The purpose of this study was to determine whether a single full therapeutic dose (24 mg) of ephedrine taken orally has any effect upon physical performance and fitness. Twenty-one healthy males, aged 19–30 years, were tested on three occasions within three weeks using a double-blind modified crossover design. The effects of ephedrine were determined by comparing the differences between drug and control conditions using paired t-tests. The test battery included measures of muscle strength, endurance and power, lung function, reaction time, hand-eye coordination, anaerobic capacity and speed, cardio-respiratory endurance, and responses to maximal and sub maximal effort, including maximum oxygen intake, ratings of perceived exertion and speed of recovery from effort. Despite a slight stimulating effect on blood pressure and on exercise and recovery heart rates, 24 mg of ephedrine had no effect on any of the measures of physical work capacity. Ephedrine had no effect on lung function of healthy young men, but may have assisted the learning of certain simple psychomotor tasks.

ISSN:0025-7990    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

A comparison of the cardiorespiratory responses obtained using both a longitudinal and cross-sectional evaluation of an endurance training program was made in two groups of 60 young male military personnel. Both groups were initially tested (T1) and then retested 6 months later (T2). At T1, Group I was a sample of personnel not participating in a training program while Group II had undergone a 5-month endurance program (2–4 mile run/day). At T2, Groups I and II had been participating in the program for 6 and 11 months, respectively. Testing consisted of sub-maximal and maximal determinations of $o2, $Eand heart rate (HR) using an interrupted treadmill test. $o2max was 11% greater in Group II compared to Group I at T1and increased 10% in Group I at T2. Similar results were also seen for HR sub max, HR max and $Emax. These results show that similar values indicative of an improved level of cardiorespiratory fitness can be obtained using either a cross-sectional or longitudinal design when relatively homogeneous groups are studied.

ISSN:0025-7990    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

Maximal aerobic capacity of 66 ten year old ice hockey players was measured on a treadmill twice over a 4 to 5 month period. Tin's time approximated mid (T1) to post (T2) competitive season. The results of these $o2max tests were grouped according to the presence or absence of a plateau in the oxygen uptake (< 2.1 ml/kg$min) during the last work loads before fatigue. The mean values for T1and T2were not significantly different for any of the measurements made; the reproducibility was considered to be high. The reliability of the measures varied with the presence or absence of a plateau at maximum, for example; $o2max, plateau r = 0.74, no plateau r = 0.27; heart rate, plateau r = 0.92, no plateau r = 0.40. The differences between the mean values for the “double plateau” group when compared to the “no plateau” group were not significant for $o2max, HR or $E. The differences were significant for the post-exercise blood lactate and respiratory exchange values at T2only; the “double plateau” group reached higher values in each case (R = 1,00 vs 0.92; blood lactate 6.5 vs 5.4 mM/1).

ISSN:0025-7990    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

Muscle samples from the vastus lateralis and maximal oxygen uptakes were obtained from 22 male and 7 female competitive cyclists, 19 untrained males, and 10 untrained females. Eleven of the 22 male cyclists were designated elite cyclists (Group A) on the basis of their success in national and/or international competition. The remaining 11 male cyclists (Group B) were also trained hut had not achieved the same level of competitive success. Significant mean differences (P < .0.05) between Croups A and B were found for $o2max (67 and 57 ml/kg/min), malate dehydrogenase (MDH) and phosphorylase (PH), in biopsied muscle. No differences were evident between Groups A and B) for % slow twitch (ST) and % fast twitch (FT) fibers, or in area FT or ST. Nor was there any difference in the mean activities of su$inate dehydrogenase (SDH) and lactate dehydrogenase (LDH) between the groups. Significant correlations were found between $o2max and SDH, $o2max and MDH, and between SDH and MDH. These data also indicate that an extremely high percentage of FT or ST fibers may not be a requirement for success in competitive cycling as has been found in earlier studies on sprint or endurance running.

ISSN:0025-7990    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

Vo2was obtained for 10 women bicycling on rollers at 3 saddle heights (SH), 95, 100 and 105% trochanteric height. Kinematic patterns described by the hip, knee, ankle and foot were discerned from one pedal cycle at each of the 3 SH. Subjects cycled on a Fuji Dynamic 10 10-speed bicycle, at 60 rpm, (a work load of 799 kpm/min was applied by a tensioning belt from a bicycle ergometer) until they reached steady state. Expired air was then collected and cine films were taken during gas collection. The 100% SH was most efficient, mean values for 95, 100 and 105% SH were 1.69, 1.61 and 1.74 lit/min, respectively. Kinematic patterns showed no variation in the range of motion (ROM) at the hip, values at the dead centers (DC) did change. The ROM at the knee varied from 69 to 82.9 degrees, 95 to 105% SH, values at the DC varied also. Plantar flexion (PF) at bottom dead center increased by 10% from 95 to 105% SH. Foot angle showed no significant variation with increasing SH. The major adaptations to increases in SH are found at the knee and in ankle PF.

ISSN:0025-7990    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

The purpose of this investigation was to gain insight, through measuring various performance, cardiopulmonary, and anthropometric parameters, to the upper functional limits for man in the eighth decade of life. The subject holds age-group record times for 16.1, 40.2, 80.5, and 171.4 km. Remarkable aerobic power was exhibited while cycling on a bicycle ergometer depicted by high values for $o2max 4.7 l/min (STPD) and 59.9 ml/kg BW$min (STPD), VE 159 l/min (BTPS), O2; pulse 0.36 ml/kg/heat and heart rate max 166 bents/mm. $o2max is the highest value reported for a man over 70 years of age. To provide inference to the aging process and to training, comparisons were made with data from the normal population of similar age and with data from young and endurance athletes. Cardiopulmonary data and body composition measures equalled that for similar age athletes and were comparable to younger endurance athletes. The findings have significant implications in determining upper functional standards for well-trained older males.

ISSN:0025-7990    

出版商:OVID    

年代:1977

数据来源: OVID

摘要:

The effect of an enriched inspired oxygen concentration on perceived exertion (RPE) was investigated while running at two submaximal treadmill loads. Twelve males ($o2max = 49.3 ml/kg$min) worked at 50% and 80% $o2max, breathing either air or 80% O2-20% N2in random order using a single blind technique. Subjects were evaluated while running for 10 min and during a 20 min recovery. Heart rate (HR), ventilation ($E), respiration rate (RR), tidal volume (VT) and RPE were measured before, during and after work. Blood lactate was measured 1 min after work. Oxygen concentration did not statistically affect HR, VE, RR or VT during exercise or recovery. At both loads, RPE at the end of exercise was significantly reduced breathing the hyperoxic mixture. At 50% Vo2max, mean RPE decreased from 11.2 breathing room air to 9.6 breathing 80% O2and, at 80% Vo2max, from 13.8 to 11.7 (P < 0.01). Blood lactates were significantly reduced breathing 80% O2; from 23.4 mg% to 13.3 at 50% Vo2max and from 55.5 to 36.5 at 80% Vo2max (P<0.01). The RPE correlated with lactate (r = 0.64) at the end of work. Results indicate that during moderate and heavy work RPE is significantly affected by the inspired O2concentration and there is a significant relationship between RPE and blood lactate.

ISSN:0025-7990    

出版商:OVID    

年代:1977

数据来源: OVID