Similar substrate oxidation rates in concentric and eccentric cycling matched for aerobic power output

2016 ◽  
Vol 41 (11) ◽  
pp. 1204-1207 ◽  
Author(s):  
Laurie Isacco ◽  
Ophélie Ritter ◽  
Nicolas Tordi ◽  
Davy Laroche ◽  
Bruno Degano ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Eccentric Exercise ◽  
Power Output ◽  
State Energy ◽  
Respiratory Exchange Ratio ◽  
Aerobic Power ◽  
Substrate Oxidation ◽  
Oxidation Rates ◽  
Postprandial State ◽  
Aerobic Power Output

This study investigated substrate oxidation in concentric and eccentric cycling matched for aerobic power output in the postprandial state. Energy expenditure, respiratory exchange ratio, and fat and carbohydrate oxidation rates were measured at rest and after 15, 30, and 45 min of eccentric and concentric cycling in 12 men. Absolute and relative aerobic power output and energy expenditure were similar during concentric and eccentric exercise. No effect of exercise modality was observed for substrate metabolism.

Does Cerebral Blood Flow Limit Maximal Aerobic Power Output?

2011 ◽  
Vol 43 (Suppl 1) ◽  
pp. 82
Author(s):  
Andrew W. Subudhi ◽  
J Tod Olin ◽  
Andrew C. Dimmen ◽  
Bengt Kayser ◽  
Robert C. Roach
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Power Output ◽  
Aerobic Power ◽  
Maximal Aerobic Power ◽  
Flow Limit ◽  
Aerobic Power Output

The Cycling Physiology of Miguel Indurain 14 Years After Retirement

2012 ◽  
Vol 7 (4) ◽  
pp. 397-400 ◽  
Author(s):  
Iñigo Mujika
Keyword(s):  
Oxygen Uptake ◽  
Blood Lactate ◽  
Body Mass ◽  
Power Output ◽  
Aerobic Power ◽  
Cycle Ergometer ◽  
Cycle Ergometer Test ◽  
Age Related ◽  
The Individual ◽  
Aerobic Power Output

Age-related fitness declines in athletes can be due to both aging and detraining. Very little is known about the physiological and performance decline of professional cyclists after retirement from competition. To gain some insight into the aging and detraining process of elite cyclists, 5-time Tour de France winner and Olympic Champion Miguel Indurain performed a progressive cycle-ergometer test to exhaustion 14 y after retirement from professional cycling (age 46 y, body mass 92.2 kg). His maximal values were oxygen uptake 5.29 L/min (57.4 mL · kg−1 · min−1), aerobic power output 450 W (4.88 W/kg), heart rate 191 beats/min, blood lactate 11.2 mM. Values at the individual lactate threshold (ILT): 4.28 L/min (46.4 mL · kg−1 · min−1), 329 W (3.57 W/kg), 159 beats/min, 2.4 mM. Values at the 4-mM onset of blood lactate accumulation (OBLA): 4.68 L/min (50.8 mL · kg−1 · min−1), 369 W (4.00 W/kg), 170 beats/min. Average cycling gross efficiency between 100 and 350 W was 20.1%, with a peak value of 22.3% at 350 W. Delta efficiency was 27.04%. Absolute maximal oxygen uptake and aerobic power output declined by 12.4% and 15.2% per decade, whereas power output at ILT and OBLA declined by 19.8% and 19.2%. Larger declines in maximal and submaximal values relative to body mass (19.4–26.1%) indicate that body composition changed more than aerobic characteristics. Nevertheless, Indurain’s absolute maximal and submaximal oxygen uptake and power output still compare favorably with those exhibited by active professional cyclists.

Physiological and Mechanical Indices Serving the New Cross-Country Olympic Mountain Bike Performance

2020 ◽  
pp. 1-6
Author(s):  
Arnaud Hays ◽  
Caroline Nicol ◽  
Denis Bertin ◽  
Romain Hardouin ◽  
Jeanick Brisswalter
Keyword(s):  
Power Output ◽  
Aerobic Power ◽  
Multiple Regression Model ◽  
Maximal Aerobic Power ◽  
Maximum Power ◽  
Active Recovery ◽  
Mountain Bike ◽  
Testing Protocol ◽  
Cross Country ◽  
Aerobic Power Output

Objectives: To identify relevant physiological, mechanical, and strength indices to improve the evaluation of elite mountain bike riders competing in the current Cross-Country Olympic (XCO) format. Methods: Considering the evolution of the XCO race format over the last decade, the present testing protocol adopted a battery of complementary laboratory cycling tests: a maximal aerobic consumption, a force–velocity test, and a multi-short-sprint test. A group of 33 elite-level XCO riders completed the entire testing protocol and at least 5 international competitions. Results: Very large correlations were found between the XCO performance and maximal aerobic power output (r = .78; P < .05), power at the second ventilation threshold (r = .83; P < .05), maximal pedaling force (r = .77; P < .05), and maximum power in the sixth sprint (r = .87; P < .05) of the multi-short-sprint test. A multiple regression model revealed that the normalized XCO performance was predicted at 89.2% (F3,29 = 89.507; r = .95; P < .001) by maximum power in the sixth sprint (β = 0.602; P < .001), maximal pedaling rate (β = 0.309; P < .001), and relative maximal aerobic power output (β = 0.329; P < .001). Discussion: Confirming our expectations, the current XCO performance was highly correlated with a series of physiological and mechanical parameters reflecting the high level of acyclic and intermittent solicitation of both aerobic and anaerobic metabolic pathways and the required qualities of maximal force and velocity. Conclusion: The combination of physiological, mechanical, and strength characteristics may thus improve the prediction of elite XCO cyclists’ performance. It seems of interest to evaluate the ability to repeatedly produce brief intensive efforts with short active recovery periods.

Abstract P125: Multiple Measures of Energy Expenditure and Substrate Oxidation in Non-obese White and African American Young Adults

Circulation ◽  
2018 ◽  
Vol 137 (suppl_1) ◽  
Author(s):  
Peter T Katzmarzyk ◽  
Eric Ravussin
Keyword(s):  
Physical Activity ◽  
Energy Expenditure ◽  
Fat Oxidation ◽  
Substrate Oxidation ◽  
Activity Level ◽  
Fat Free Mass ◽  
Free Living ◽  
Multiple Measures ◽  
Oxidation Rates ◽  
Increased Risk

Introduction: African Americans (AA) experience higher rates of obesity and related disorders than the general U.S. population. It has been hypothesized that the increased risk of obesity among AA may be explained, in part, by lower levels of energy expenditure (EE) and lower levels of fat oxidation. However, many different measures of EE and substrate oxidation have been employed across previous studies. Objective: The objective of this study was to compare multiple measures of EE and substrate oxidation among White (W) and AA adults. We hypothesize that AA will have lower EE and lower fat oxidation rates than W. Methods: A sample of 12 young (ages 22 to 35 y), non-obese AA adults was recruited from the local community and pair-matched by age, sex and body mass index (BMI) to a sample of 12 W adults. Height and weight were measured and BMI was calculated (kg/m 2 ). Total fat mass (FM) and fat free mass (FFM) were measured using dual energy x-ray absorptiometry. Resting EE (REE) and respiratory quotient (RQ) were measured in a fasting state using a metabolic cart; 24-hour EE, 24-h RQ, sleep EE and sleep RQ were measured in a whole room calorimeter; and free-living total daily EE (TDEE) was measured over two weeks using doubly labelled water. Physical activity level (PAL) was computed as TDEE/REE. Differences between W and AA were determined using general linear models, adjusting for FFM. Results: The analytic sample had a mean age of 27.0 y (SD 4.3 y) and mean BMI of 22.9 kg/m 2 (SD 2.9 kg/m 2 ). There were no significant differences in age, BMI, FM or FFM between W and AA (all p>0.05). However, W had significantly higher REE (1459 vs 1305 kcal/day; p=0.001), 24-h EE (1826 versus 1737 kcal/day; p=0.02), sleep EE (1509 vs 1405 kcal/day; p=0.005); but not TDEE (2452 vs 2313 kcal/day; p=0.30) compared to AA. There were no race differences in RQ (0.83 vs 0.83; p=0.93), 24-h RQ (0.86 vs 0.88; p=0.24) or sleep RQ (0.86 vs 0.87; p=0.44). On the other hand, AA had higher PAL (1.34 vs 1.26; p=0.04) compared to W. Conclusions: Non-obese W adults demonstrated higher REE, 24-h EE, and sleep EE compared to AA, but had similar levels of free-living TDEE. It appears as though some AA adults may compensate for lower REE by increased physical activity, which may be an effective strategy to prevent weight gain and obesity.

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