Work and power outputs determined from pedalling and flywheel friction forces during brief maximal exertion on a cycle ergometer

1996 ◽  
Vol 74 (5) ◽  
pp. 435-442 ◽  
Author(s):  
Naohiro Hibi ◽  
Hiroshi Fujinaga ◽  
Kihachi Ishii
Keyword(s):  
Cycle Ergometer ◽  
Friction Forces ◽  
Power Outputs

Design and Evaluation of a Modified Underwater Cycle Ergometer

1996 ◽  
Vol 21 (2) ◽  
pp. 134-148 ◽  
Author(s):  
An A. Chen ◽  
Glen P. Kenny ◽  
Chad E. Johnston ◽  
Gordon G. Giesbrecht
Keyword(s):  
Power Output ◽  
Maximal Exercise ◽  
Exercise Duration ◽  
Cycle Ergometer ◽  
Gear Ratio ◽  
Upright Position ◽  
Exercise Tests ◽  
Maximal Power Output ◽  
Power Outputs ◽  
Key Words Core Temperature

An underwater cycle ergometer was designed consisting of an aluminum cycle frame in water connected with a 1:1 gear ratio to a mechanically braked standard cycle ergometer supported above the water. Three progressive maximal exercise tests were performed (n = 10): (a) the underwater ergometer in water (UEW), (b) underwater ergometer in air (UEA), and (c) a standard cycle ergometer in air (SEA). At submaximal power outputs, oxygen consumption [Formula: see text] and heart rate (HR) were generally lower in the SEA condition (p <.05), indicating that exercise in the upright position was more efficient. Exercise in water (UEW) resulted in lower total exercise duration, maximal HR, and maximal Tes than in air conditions. The upright position (SEA) resulted in greater total exercise duration and maximal power output than the semirecumbent positions. Because of positional differences between the standard and underwater ergometers, air-water comparisons should be made by using the underwater ergometer in water and on land. Key words: core temperature, esophageal temperature, skin temperature, exercise, resistance, work, power output, heat balance, heat loss, heat production, thermoregulation

O2 uptake kinetics and the O2 deficit as related to exercise intensity and blood lactate

1993 ◽  
Vol 75 (2) ◽  
pp. 755-762 ◽  
Author(s):  
T. J. Barstow ◽  
R. Casaburi ◽  
K. Wasserman
Keyword(s):  
Blood Lactate ◽  
Time Constant ◽  
Exercise Intensity ◽  
Power Output ◽  
Cycle Ergometer ◽  
O2 Uptake ◽  
Ergometer Exercise ◽  
Lactate Levels ◽  
Power Outputs ◽  
O2 Deficit

The dynamic responses of O2 uptake (VO2) to a range of constant power output levels were related to exercise intensity [as percent maximal VO2 and as below vs. above lactic acid threshold (LAT)] and to the associated end-exercise lactate in three groups of subjects: group I, untrained subjects performing leg cycle ergometer exercise; group II, the same subjects performing arm cycle exercise; and group III, trained cyclists performing leg cycle ergometer exercise. Responses were described by a double-exponential equation, with each component having an independent time delay, which reduced to a monoexponential description for moderate (below-LAT) exercise. When a second exponential component to the VO2 response was present, it did not become evident until approximately 80–100 s into exercise. An overall time constant (tau T, determined as O2 deficit for the total response divided by net end-exercise VO2) and a primary time constant (tau P, determined from the O2 deficit and the amplitude for the early primary VO2 response) were compared. The tau T rose with power output and end-exercise lactate levels, but tau P was virtually invariant, even at high end-exercise lactate levels. Moreover the gain of the primary exponential component (as delta VO2/delta W) was constant across power outputs and blood lactate levels, suggesting that the primary VO2 response reflects a linear system, even at higher power outputs. These results suggest that elevated end-exercise lactate is not associated with any discernible slowing of the primary rise in VO2.(ABSTRACT TRUNCATED AT 250 WORDS)

Torso Stabilization Reduces the Metabolic Cost of Producing Cycling Power

2005 ◽  
Vol 30 (4) ◽  
pp. 433-441 ◽  
Author(s):  
John McDaniel ◽  
Andrew Subudhi ◽  
James C. Martin
Keyword(s):  
Ventilatory Threshold ◽  
Muscle Metabolism ◽  
Control Unit ◽  
Metabolic Cost ◽  
Cycle Ergometer ◽  
Whole Body ◽  
Strongly Correlated ◽  
Wide Range ◽  
Static Contraction ◽  
Power Outputs

Many researchers have used cycling exercise to evaluate muscle metabolism. Inherent in such studies is an assumption that changes in whole-body respiration are due solely to respiration at the working muscle. Some researchers, however, have speculated that the metabolic cost of torso stabilization may contribute to the metabolic cost of cycling. Therefore, our primary purpose was to determine whether a torso stabilization device would reduce the metabolic cost of producing cycling power. Our secondary purpose was to determine the validity of the ergometer used in this study. Nine male cyclists cycled on a Velotron cycle ergometer at mechanical power outputs intended to elicit 50, 75, and 100% of their ventilatory threshold at 40, 60, and 80 rpm, with and without torso stabilization. Power was controlled by the Velotron in iso-power mode and measured with an SRM powermeter. We determined metabolic cost by indirect calorimetery and recorded power output. Torso stabilization significantly reduced metabolic cost of producing submaximal power (1%), and reduction tended to be greatest at the lower pedaling rates where pedaling force was greatest (1.6% at 40 rpm, 1.2% at 60 rpm, 0.2% at 80 rpm). Power, measured with the SRM powermeter, was strongly correlated with that specified to the Velotron ergometer control unit (R2 > 0.99). We conclude that muscular contractions associated with torso stabilization elicit significant metabolic costs, which tend to be greatest at low pedaling rates. Researchers who intend to make precise inferences regarding metabolism in the working muscles of the legs may wish to provide torso stabilization as a means of reducing variability, particularly when comparing metabolic data across a wide range of pedaling rates. Key words: efficiency, economy, metabolism, static contraction, work

Effects of acute and chronic maternal exercise on fetal heart rate

1994 ◽  
Vol 77 (5) ◽  
pp. 2207-2213 ◽  
Author(s):  
K. A. Webb ◽  
L. A. Wolfe ◽  
M. J. McGrath
Keyword(s):  
Heart Rate ◽  
Fetal Heart Rate ◽  
Fetal Heart ◽  
Cycle Ergometer ◽  
Fetal Hypoxia ◽  
Aerobic Conditioning ◽  
Maternal Exercise ◽  
Power Outputs ◽  
Sedentary Women ◽  
Normal Variability

Maternal-fetal effects of cycle ergometer conditioning (heart rate of 145 beats/min at 25 min/day for 3 days/wk) were studied during the second and third pregnancy trimesters. Subjects were 22 previously sedentary women and 16 nonexercising pregnant control women. Fetal heart rate (FHR) characteristics were studied before, during, and after 15 min of upright cycling at a maternal heart rate target of 145 beats/min at the end of both the second and third trimesters. Despite higher cycling power outputs in the exercised group, mean FHR responses were similar in both groups and conformed to 1) gradual increase in FHR baseline during exercise, 2) normal variability, and 3) normal reactivity. Fetal bradycardia was observed during (n = 1) and after (n = 2) exercise in three isolated tests. The timing of these events suggested that the likelihood of significant fetal hypoxia is highest in the immediate postexercise period. These results also support the hypothesis that physically conditioned women can perform at higher exercise power outputs than sedentary women without inducing fetal hypoxic stress. Further study is recommended to examine possible fetal and placental adaptations to maternal aerobic conditioning.

A computer simulation of free-range exercise in the laboratory

1999 ◽  
Vol 87 (4) ◽  
pp. 1386-1391 ◽  
Author(s):  
E. Terblanche ◽  
J. A. Wessels ◽  
R. I. Stewart ◽  
J. H. Koeslag
Keyword(s):  
Computer Simulation ◽  
Aerodynamic Drag ◽  
Cycle Ergometer ◽  
Input Stimulus ◽  
Laboratory Exercise ◽  
Free Range ◽  
Drag Forces ◽  
Wide Range ◽  
Power Outputs ◽  
Fundamental Requirement

We present a technique for simulating dynamic field (free-range) exercise, using a novel computer-controlled cycle ergometer. This modified cycle ergometer takes into account the effect of friction and aerodynamic drag forces on a 70-kg cyclist in a racing position. It also affords the ability to select different gear ratios. We have used this technique to simulate a known competition cycle route in Cape Town, South Africa. In an attempt to analyze the input stimulus, in this case the generated power output of each cyclist, eight subjects cycled for 40 min at a self-selected, comfortable pace on the first part of the simulated route. Our results indicate that this exercise input excites the musculocardiorespiratory system over a wide range of power outputs, both in terms of amplitude and frequency. This stimulus profile thereby complies with the fundamental requirement for nonlinear (physiological) systems analysis and identification. Through a computer simulation, we have devised a laboratory exercise protocol that not only is physiologically real but also overcomes the artificiality of most traditional laboratory exercise protocols.

Endurance training reduces the magnitude of exercise-induced hyperammonemia in humans

1987 ◽  
Vol 62 (3) ◽  
pp. 1227-1230 ◽  
Author(s):  
P. Y. Lo ◽  
G. A. Dudley
Keyword(s):  
Exercise Training ◽  
Aerobic Power ◽  
Energy Requirement ◽  
Work Load ◽  
Cycle Ergometer ◽  
Ammonia Content ◽  
Continuous Cycling ◽  
Exercise Induced ◽  
Power Outputs ◽  
Intensity Of Exercise

The purpose of this study was to determine the influence of endurance-type exercise training on alterations of the ammonia content of blood in exercising humans. Seven females and four males trained 6 days/wk for 7 wk alternating days of continuous cycling (40 min) and interval running (five 5-min bouts). The NH3 content of blood was determined before and during cycle ergometer (CE) exercise (4 min) at power outputs (PO) of 119, 172, and 241 W pretraining and of 163, 230, and 271 W posttraining. These PO for each occasion represent relative work loads of approximately 65, 90, and 115% of peak CE maximum O2 uptake (PCE VO2), respectively. Training increased (P less than 0.05) PCE VO2 approximately 32% (2.72 +/- 0.25 to 3.56 +/- 0.29 l/min or 38.5 +/- 1.9 to 51.2 +/- 2.3 ml X kg-1 X min-1). Both pre- and posttraining the NH3 content of blood increased (P less than 0.05) with increasing intensity of exercise. Training did not influence the measure of these responses during exercise at the same relative intensity. During exercise at the same absolute PO, approximately 168 or 235 W, however, increases in blood NH3 were less (P less than 0.05) after training. The results indicate that the magnitude of increase in blood NH3 during exercise is determined by the energy requirement of the absolute work load, relative to an individual's aerobic power.

Metabolic parameters for ramp versus step incremental cycle ergometer tests

2012 ◽  
Vol 37 (6) ◽  
pp. 1110-1117 ◽  
Author(s):  
Jorge M. Zuniga ◽  
Terry J. Housh ◽  
Clayton L. Camic ◽  
Haley C Bergstrom ◽  
Daniel A. Traylor ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Perceived Exertion ◽  
Polynomial Regression ◽  
Cycle Ergometer ◽  
Rating Of Perceived Exertion ◽  
Total Work ◽  
Regression Analyses ◽  
Mean Values ◽  
The Common ◽  
Power Outputs

The purpose of this study was to examine mean differences and the patterns of responses for oxygen uptake ([Formula: see text]O2), heart rate (HR), and rating of perceived exertion (RPE) for ramp (15 W·min–1) versus step (30 W increments every 2 min) incremental cycle ergometer tests. Fourteen subjects (age and body mass of 23.2 ± 3.1 (mean ± SD ) years and 71.1 ± 10.1 kg, respectively) visited the laboratory on separate occasions. Two-way repeated measures ANOVAs with appropriate follow-up procedures, as well as paired t tests, were used to analyze the data. In addition, polynomial regression analyses were used to determine the patterns of responses for each dependent variable for the ramp and step tests. The ramp protocol resulted in lower mean [Formula: see text]O2 and HR values at the common power outputs than the step protocol with no differences in RPE. The increased amount of work performed during the step (total work = 75.83 kJ) versus ramp (total work = 65.60 kJ) tests at the common power outputs may have contributed to the greater [Formula: see text]O2 and HR values. The polynomial regression analyses showed that most subjects had the same patterns of responses for the ramp and step incremental tests for HR (86%) and RPE (93%) but different patterns for [Formula: see text]O2 (71%). The findings from the present study suggested that the protocol selection for an incremental cycle ergometer test can affect the mean values for [Formula: see text]O2 and HR, as well as the [Formula: see text]O2 – power output relationship.

Vo2 requirement at different displayed power outputs on five cycle ergometer models: a preliminary study

2008 ◽  
Vol 44 (6) ◽  
pp. 449-454 ◽  
Author(s):  
T. Guiraud ◽  
L. Leger ◽  
A. Long ◽  
N. Thebault ◽  
J. Tremblay ◽  
...  
Keyword(s):  
Cycle Ergometer ◽  
Preliminary Study ◽  
Power Outputs

Metabolic and Perceptual Responses to Short-Term Cycle Training in Children

1998 ◽  
Vol 10 (2) ◽  
pp. 110-122 ◽  
Author(s):  
Glen E. Duncan ◽  
Edward T. Howley
Keyword(s):  
Perceived Exertion ◽  
Training Group ◽  
Cycle Ergometer ◽  
Submaximal Exercise ◽  
Control Group ◽  
Ratings Of Perceived Exertion ◽  
Short Term ◽  
Cycle Training ◽  
Power Outputs ◽  
And Control

Metabolic and perceptual responses to cycle training were investigated in children in a training group (TG, N = 10) and control group (CG, N = 13). Prior to training, aerobic power (VO2peak) was assessed, and children performed submaximal exercise at graded power outputs. Substrate use was calculated for each level using the respiratory exchange ratio (RER) and metabolic rate, and ratings of perceived exertion (RPE) were obtained to estimate perceptual effort. Training consisted of 12 sessions (three 10-min work bouts 3 times/week, 50% VO2peak) on a cycle ergometer. After 4 weeks, RER and RPE were reevaluated at the same absolute intensities. Overall difference scores indicated a decrease in RER and RPE in the TG and an increase in RER with * no change in RPE in the CG. These data demonstrate that short-term cycle training in children results in enhanced fat use and diminished perception of effort during submaximal exercise.

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