SEARCH · PubMed Health

Results for “Bicycling”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

PubMed1978

Oxygen uptake and blood flow of the lower limb in maximal treadmill and bicycle exercise.

The present study was undertaken to compare the effects of maximal treadmill and bicycle exercise on maximum oxygen uptake and blood flow in the lower extremity. Mean maximum oxygen uptake in maximal treadmill exercise was higher than that in bicycle exercise (p less than 0.001). Mean values and standard errors of blood flow measured immediately after maximal treadmill and bicycle exercise in the thigh were 39.1 +/- 4.0 and 44.2 +/- 2.8 ml/100 ml . min, the difference not being significant. However, a significant difference in blood flow in the calf measured immediately after both types of exercise was observed (p less than 0.001). Blood flow in the thigh immediately after bicycle exercise was significantly higher than that in the calf (p less than 0.001), whereas the difference between thigh and calf in treadmill exercise was small and statistically not significant. Leg blood flow, the average value of blood flow of the thigh and calf added together, was used as an index of blood flow in the lower extremity. It was found that the leg blood flow was significantly higher on the treadmill than with bicycle exercise (p less than 0.05). From these results, it is suggested that the lower maximum oxygen uptake observed during bicycle exercise as compared with treadmill exercise seems to be due to a lower blood flow in the lower limb.

Adult↗

PubMed1979

[Comparison of bicycle ergometry and step-ladder exercise (author's transl)].

Repeat exercises (three hours apart) on a bicycle ergometer and a vertical step-ladder were performed in a randomised series on 79 subjects: 13 doctors, 44 patients and 22 sportsmen. Duration of exercise was on average 250% longer in the three groups on the step-ladder than the bicycle. Correspondingly, exercise-pulse sums, recovery-pulse sums and exercise indices were two-and-a-half to three times higher than on bicycle ergometry. As a sign of comparability of the exercise by the two methods there was, on average, no significant difference with regard to the final heart rate, although duration of exercise was longer on the step-ladder. 67% of subjects discontinued the exercise because of peripheral muscle fatigue on the bicycle ergometer, compared with only 8% on the step-ladder. During bicycle ergometry lactate concentration rose by 6.7 mmol/l compared with only 0.78 mmol/l during step-ladder exercise. These results indicate that the value of bicycle ergometry exercise is limited by muscle fatigue in the legs: step-ladder exercise can be extended much longer. The practical significance is that patients with coronary heart disease especially have symptoms and/or ECG changes of ischaemia only at higher levels of physical exercise.

Adolescent↗

PubMed1979

A comparison of the oxygen consumption/body weight relationship obtained during submaximal exercise on a bicycle ergometer and on a treadmill.

It is widely accepted that the relationship between oxygen consumption and body weight obtained during exercise on a bicycle ergometer differs from that obtained during treadmill walking. Experimental evidence to support this claim is lacking. To examine this difference a group of subjects (body weight 41--81 kg) undertook a predetermined level of submaximal exercise on a bicycle ergometer and a treadmill. Oxygen consumption was measured in a steady state at rest (i.e. sitting on the bicycle ergometer and standing on the treadmill) and during the two modes of exercise. A significant positive correlation between oxygen consumption and body weight was obtained under all four conditions of measurement. At rest the two regression lines did not differ in slope or elevation. During exercise the slope and the elevation of the line obtain from treadmill walking were significantly greater than from bicycle ergometer exercise. The 'metabolic cost' of bicycle ergometer exercise, (Vo2 during exercise--V02 at rest), showed no significant correlation with body weight. In contrast, there was a significant positive correlation during walking. It is suggested that these differences have arisen due to a different proportion of the total body weight supported by the subject in the two forms of exercise.

Adult↗

PubMed1978

Syntheses of monocyclic and bicyclic peptides of tryptathionine and glycine.

L-3a-Hydroxy-1.2.3.3a.8.8a-hexahydropyrrolo [2,3-b-]-indole-2-carboxylic acid (Hpi), obtained from L-tryptophan by oxidation with peroxyacetic acid (Savige, 1975), after introduction of the Boc-residue at N-1, is coupled with various glycine peptides of S-trityl-L-cysteine to give the Hpi-peptides 6(a-f). By treatment with absolute trifluoroacetic acid these peptides are converted by an intramolecular thiolysis to the monocyclic thioethers 7(a-f). Two of them, 7e and 7f, can be subjected to a second cyclization by the mixed anhydride method thus yielding the bicyclic tryptathionine heptapeptide 8e and octapeptide 8f. In their structures the bicyclic molecules resemble the mushroom phallotoxins and amatoxins, respectively. They show CD spectra closely related to the naturally occurring bicyclic peptides thus indicating conformational similarities. The CD spectra of the other cyclic peptides synthesized are also presented and discussed.

Chemical Phenomena↗

PubMed1978

Comparison of metabolic and ventilatory responses of men to various lifting tasks and bicycle ergometry.

Four male volunteers served as subjects to examine the metabolic and ventilatory cost of both positive and negative lifting tasks as compared to bicycle ergometry. In different experiments, four boxes weighing 0.91, 6.82, 22.73, and 36.36 kg were lifted up to or down from a height of 60 cm at rates as high as 70 lifts/min for periods of 4 min. The data were then compared to those obtained from bicycling at a rate of 50 rpm at work loads up to 1,500 kmp/min. Work at any given box weight had a substantially higher oxygen and ventilatory cost than similar levels of work on the bicycle ergometer. The reason for these differences appeared to lie in the energy cost of moving parts of the body. When the weight of the boxes was low, there was little difference between the oxygen cost of positive and negative work, but as the weight of the boxes increased, the expected physiological differences in positive and negative work was established.

Adult↗

PubMed1979

Bicycle spoke fracture.

Twenty-nine children were treated for bicycle spoke injury, which occurred while they were sitting behind their riding parents. Their feet were caught in between the bicycle spoke and the frame rod. Five of these children suffered supramalleolar fracture. These fractures had a similar radiographic pattern, namely a greenstick fracture of the distal end of the tibia and fibula, buckling into varus and usually also into anterior angulation. Healing of the fractures was uneventful. These injuries are preventable by rigid plastic net covers for the rear wheel of the bicycle.

Ankle Injuries↗

PubMed1979

[Significance of the atrial stimulation test in the diagnosis of ischemic heart disease. A comparison with measured physical loading on the bicycle ergometer and with coronary angiographic data].

The results of the atrial stimulation test were compared with the data of the test on a bicycle ergometer and coronary arteriography. The atrial stimulation test made it possible to diagnose coronary insufficiency in 91.6% of patients with ischemic heart disease. It was established that atrial stimulation helps in determining exactly the causes of a vague cardialgic syndrome in some cases in which the test on a bicycle ergometer cannot be carried out or when it is difficult to appraise its results. As compared to the test with dosed physical load on a bicycle ergometer, the atrial stimulation test proved more sensitive and less specific.

Adult↗

PubMed1978

[Bicycle spiroergometric studies in the diagnosis of ischemic heart disease].

The indices of pulmonary ventilation and gas exchange, oxygen consumption per 1 kgm of work, the restoration coefficient, the effectiveness of work, etc. were studied at rest, during dosaged physical exertion on a bicycle ergoraph, and in the restoration period in 50 healthy individuals and in 175 patients with ischemic heart disease. Selective coronary angiography was conducted in all of the patients. Spiro-bicycle-ergometry is an informative method in the diagnosis of ischemic heart disease, enabling the physician to presume the presence of coronary sclerosis and judge the degree and extent of involvement of the coronary arteries before performing coronarography. With the gradual increase in the number of involved arteries, there were noted a gradual decrease of the restoration coefficient, diminution of the effectiveness of work, and an increase in oxygen consumption per 1 kgm of load. Changes in spiro-bicycle-ergometric indices in patients with ischemic heart disease and normal coronary arteries had the same trend as those in patients with coronary atherosclerosis.

Adult↗

PubMed1978

Conformationally restricted bicyclic analogs of somatostatin.

A model for a biologically active conformation of somatostatin is proposed. This model is based primarily on the biological results obtained with novel bicyclic somatostatin analogs having a covalent bridge replacing the side chains of residues 5 and 10, 6 and 11, and 5 and 12, respectively, rather than on physical measurements on the hormone in solution. The high activity of an analog in which Phe6 and Phe11 are replaced by cystine provides evidence that these phenylalanines stabilize the biologically active conformer through "hydrophobic bonding" but do not directly interact with the receptor. The synthesis of the novel bicyclic analogs of somatostatin and the effects of these on the inhibition of secretion of insulin, glucagon, growth hormone, and gastric acid are described.

Animals↗

PubMed1979

Metabolic and cardiopulmonary responses to wheelchair and bicycle ergometry.

To evaluate wheelchair activity in reference to a more familiar mode of locomotion, metabolic and cardiopulmonary responses to wheelchair ergometer (WERG) and bicycle ergometer (BERG) exercise were compared. Eighteen able-bodies subjects were tested on a combination wheelchair-bicycle ergometer. Oxygen uptake (VO2), respiratory exchange ratio (R), pulmonary ventilation (VE), ventilatory equivalent (VE/VO2), percent net mechanical efficiency (ME), and heart rate (HR) were determined at power output (PO) levels of 30, 90, and 150 kpm/min on each ergometer. For WERG and BERG exercise, VO2, VE, and HR increased linearly with PO. Generally, VO2, R, VE, VE/VO2, and HR responses were higher (P less than 0.05) during WERG than BERG exercise at each PO. Blood lactate was determined after 150 kpm/min, and found to be higher (P less than 0.05) during WERG than BERG exercise. ME increased with PO and was lower (P less than 0.05) for WERG than BERG exercise at each PO level. The greater metabolic and cardiopulmonary responses observed during WERG exercise may be due to inefficient biomechanics and the relatively small upper body musculature used for propulsion.

Adult↗

PubMed1979

Bicycle accidents in childhood.

From a total of 4589 accident cases reported from nine Sydney hospitals during 1978, 312 children, 50% of whom were five to nine years old, were injured while riding bicycles. An in-depth investigation of 139 cases showed that motor vehicles were involved on only three occasions; the children were injured as a result of inexperience and misuse. These results indicate the value of developing and implementing bicycle education programmes for younger children, especially those aged five to nine years. Equal emphasis should be given both to traffic safety instruction and to basic riding skills.

Accidents, Traffic↗

PubMed1979

[Use of the bicycle ergometric test in the differential diagnosis of climacteric cardiopathy].

Bicycle ergometry on the "Elema" electrical bicycle ergometer was conducted on 6, patients of climacteric age (41 to 55 years) with pain in the region of the heart and ECG changes. The method made it possible to confirm the diagnosis of climacteric cardiopathy in 39 and to reveal climacteric cardiopathy and concurrent ischemic heart disease in 23 patients. It was noted that physical load had a favourable effect on processes of repolarization in the myocardium of patients with climacteric cardiopathy.

Adult↗

PubMed1979

[Results of the bicycle ergometric test in stenocardia patients performing the load manually].

Comparative study was carried out of the results of the bicycle ergometry test in hand- and foot-pedalling conducted on 56 patients with stable angina pectoris. It is shown that in performing work by muscles of the shoulder girdle the chrono- and inotropic reserves of the heart are expended more rapidly, and an attack of angina develops in lesser physical exertion. It is recommended to conduct the bicycle ergometry test with hand pedalling for determining the working capacity of individuals with ischemic heart disease if their occupation is linked with physical exertion of the shoulder girdle muscles.

Aged↗

PubMed1979

Reproducibility of ejection-fraction determinations by equilibrium radionuclide angiography in response to supine bicycle exercise: concise communication.

Sixteen patients with stable, chronic coronary artery disease were studied twice within and average of 15 days to evaluate the reproducibility of ejection fraction (EF) determined by equilibrium radionuclide angiography (EQ) at rest, during supine bicycle exercise (ex), and in the recovery period (rec). Following injection of 20--25 mCi of Tc-99m-tagged human serum albumin, data were analyzed for 2-min periods at rest, during several stages of exercise (submax, max), and during recovery (rec1 = minutes 2 + 3, rec2 = minutes 9 + 10). Each patient reached similar (heart rate) X (blood pressure) products in the two studies: 21280 +/- 5200 compared with 20390 +/- 4140 mmHg/min. Mean EFs for the first and second studies were: at rest (53.0 +/- 10.8)%, 52.5 +/- 10.4)% (r = 0.95; submax ex (51.4 +/- 12.0)%, (52.1 +/- 12.8)%, (r = 0.91); max ex (50.6 +/- 12.6)%, (51.6 +/- 12.9)% (r = 0.97); rec1 (62.7 +/- 11.6)%, (62.4 +/- 12.2)% (r = 0.95); rec2 (55.5 %/- 10.8)%, (57.2 +/- 11.7)% (r = 0.91). In stable patients, the reproducibility of EF determined by EQ is excellent during rest, supine bicycle exercise, and recovery from exercise.

Adult↗

PubMed1978

Effects of pedalling rate changes on maximal oxygen uptake and perceived effort during bicycle ergometer work.

The present investigation determined the efficacy of progressively increased pedalling rate (P) or resistance (R) during assessment of maximal oxygen uptake (VO2max) on the bicycle ergometer. Twenty male and nine female university students performed randomly assigned discontinuous P and R maximal stress tests. Male subjects immedicately repeated each test within the same experimental session. Regardless of test protocol, VO2max was quite similar. Magnitude estimates of perceived effort were significantly lower for male subjects during P testing (P less than .05) and 80% of male subjects preferred P testing. Conversely, magnitude estimates were significantly lower for female subjects for R testing (P LESS THAN .05). P testing could be reliably repeated within the same experimental session whereas with R testing VO2max was significantly reduced (P LESS THAN .05). It was concluded that progressively increased pedalling rate offers a physiologically acceptable means to VO2max assessment on the bicycle ergometer for males and females. In addition, progressively increased pedalling rate offers a perceptually preferable means to VO2max assessment for males but not for females.

Adolescent↗

PubMed1979

Bicycle ergometry and gas exchange measurements in neuromuscular diseases.

Using bicycle ergometry with computerized respiratory gas exchange measurements, we compared exercise capacities in patients with various neuromuscular diseases to those in normal controls. As expected, male and female patients had significantly reduced maximum work capacities (kilopond-meters per minute per kilogram of body weight) and maximal oxygen consumptions. The oxygen cost of exercise was normal in the majority of patients, although some appeared to have abnormally high oxygen consumptions during exercise. Breathing patterns during exercise, particularly in regard to onset of hyperventilation, were similar in patients and controls.

Adolescent↗

PubMed1979

Profiles of radionuclide left ventricular ejection fraction changes induced by supine bicycle exercise in normals and patients with coronary heart disease.

This paper presents the profiles of left ventricular ejection fraction (EF) during and following supine bicycle exercise in normal subjects and in patients with coronary heart disease, as well as the relationship of the described patterns to clinical parameters. Twenty normal men and 40 patients with coronary artery disease were studied using gated equilibrium radionuclide angiography (EQ-EF). In the normals, during exercise, EF increased by a mean of 25% of the resting value, with an increase of no less than 11%. The exercise-limiting symptom in patients with coronary artery disease was angina pectoris in 20 and fatique in the other 20 patients. In the angina patients, there was a mean decrease in EF of 20%, and in the other coronary artery disease patients ejection fraction change little. Only two patients with coronary artery disease increased from a normal resting value to peak exercise by more than 11%, and they had isolated right coronary lesions. An "overshoot" elevation of ejection fraction above resting levels was demonstrated following termination of exercise in most patients. The patients with a significant fall in exercise ejection fraction more frequently had abnormal exercise-induced ECG changes as well as abnormal left ventriculograms and more severe coronary artery disease at cardiac catheterization than the patients with little change in ejection fraction. We conclude that 1) normals could be separated from most patients with significant coronary artery disease in this study population; 2) ejection fraction must be measured at maximal exercise for it to have diagnostic value, since there could be normal rise before and after peak exercise and an abnormal response missed; and 3) the ejection fraction response to exercise reflects the severity of the underlying coronary artery disease. The described patterns of exercise-induced changes in left ventricular ejection fraction are important to consider when using this new technique to diagnose and evaluate patients with coronary artery disease.

Adult↗

PubMed1979

Frequency and amplitude analysis of the EMG during exercise on the bicycle ergometer.

The surface EMG was recorded from above the quadriceps muscle in 3 male subjects during bicycle ergometry at work loads between 20 and 100% of the VO2 max to measure the EMG amplitude (RMS) and frequency (assessed from the center frequency of the power spectra) during this type of work. During brief (3 min) bouts of work the RMS amplitude of the EMG was linearly related to the work load; the center frequency of the EMG power spectra was the same at all work loads examined. In contrast, during sustained bouts of work maintained for 80 min at 20 and 40% of the VO2 max, the RMS amplitude of the EMG remained constant while the center frequency initially increased for the first 20 min of work and then progressively decreased as the work continued. When work loads of 60, 80, and 100% of the VO2 max were sustained to fatigue, the RMS amplitude continually increased while the EMG frequency decreased from the beginning to the end of the work periods. The results of this study showed that the EMG is a complex waveform, being influenced not only by fatigue, but to even a larger extent in many cases, the temperature of the exercising muscles. Therefore, although muscular fatigue caused an increase in the RMS amplitude and decrease in the center frequency, the increase in muscle temperature associated with the work opposed these changes by causing a reduction in the RMS amplitude and an increase in the center frequency.

Body Temperature↗