A REPETITIVELY PULSED CARBON DIOXIDE LASER WITH MEAN POWER OUTPUT IN EXCESS OF 30 kW

1980 ◽  
Vol 41 (C9) ◽  
pp. C9-351-C9-357 ◽  
Author(s):  
J. D.L.H. Wood ◽  
P. R. Pearson
Keyword(s):  
Carbon Dioxide ◽  
Power Output ◽  
Carbon Dioxide Laser ◽  
Mean Power ◽  
Mean Power Output

Aerobic and Anaerobic Power Distribution During Cross-Country Mountain Bike Racing

2020 ◽  
pp. 1-6
Author(s):  
Bernhard Prinz ◽  
Dieter Simon ◽  
Harald Tschan ◽  
Alfred Nimmerichter
Keyword(s):  
Power Output ◽  
Power Distribution ◽  
Anaerobic Power ◽  
Energy System ◽  
Mountain Bike ◽  
Mean Power ◽  
Anaerobic Energy ◽  
Cross Country ◽  
Mean Power Output ◽  
Aerobic And Anaerobic

Purpose: To determine aerobic and anaerobic demands of mountain bike cross-country racing. Methods: Twelve elite cyclists (7 males;  = 73.8 [2.6] mL·min-1·kg−1, maximal aerobic power [MAP] = 370 [26] W, 5.7 [0.4] W·kg−1, and 5 females;  = 67.3 [2.9] mL·min−1·kg−1, MAP = 261 [17] W, 5.0 [0.1] W·kg−1) participated over 4 seasons at several (119) international and national races and performed laboratory tests regularly to assess their aerobic and anaerobic performance. Power output, heart rate, and cadence were recorded throughout the races. Results: The mean race time was 79 (12) minutes performed at a mean power output of 3.8 (0.4) W·kg−1; 70% (7%) MAP (3.9 [0.4] W·kg−1 and 3.6 [0.4] W·kg−1 for males and females, respectively) with a cadence of 64 (5) rev·min−1 (including nonpedaling periods). Time spent in intensity zones 1 to 4 (below MAP) were 28% (4%), 18% (8%), 12% (2%), and 13% (3%), respectively; 30% (9%) was spent in zone 5 (above MAP). The number of efforts above MAP was 334 (84), which had a mean duration of 4.3 (1.1) seconds, separated by 10.9 (3) seconds with a mean power output of 7.3 (0.6) W·kg−1 (135% [9%] MAP). Conclusions: These findings highlight the importance of the anaerobic energy system and the interaction between anaerobic and aerobic energy systems. Therefore, the ability to perform numerous efforts above MAP and a high aerobic capacity are essential to be competitive in mountain bike cross-country.

scholarly journals Validity of the Velocomp PowerPod Compared With the Verve Cycling InfoCrank Power Meter

2019 ◽  
Vol 14 (10) ◽  
pp. 1382-1387 ◽  
Author(s):  
Paul F.J. Merkes ◽  
Paolo Menaspà ◽  
Chris R. Abbiss
Keyword(s):  
Power Output ◽  
Average Power ◽  
Dynamic Environment ◽  
Rolling Resistance ◽  
Mean Power ◽  
Power Meter ◽  
Test Study ◽  
Environment Study ◽  
Road Cyclists ◽  
Mean Power Output

Purpose: To determine the validity of the Velocomp PowerPod power meter in comparison with the Verve Cycling InfoCrank power meter. Methods: This research involved 2 separate studies. In study 1, 12 recreational male road cyclists completed 7 maximal cycling efforts of a known duration (2 times 5 s and 15, 30, 60, 240, and 600 s). In study 2, 4 elite male road cyclists completed 13 outdoor cycling sessions. In both studies, power output of cyclists was continuously measured using both the PowerPod and InfoCrank power meters. Maximal mean power output was calculated for durations of 1, 5, 15, 30, 60, 240, and 600 seconds plus the average power output in study 2. Results: Power output determined by the PowerPod was almost perfectly correlated with the InfoCrank (r > .996; P < .001) in both studies. Using a rolling resistance previously reported, power output was similar between power meters in study 1 (P = .989), but not in study 2 (P = .045). Rolling resistance estimated by the PowerPod was higher than what has been previously reported; this might have occurred because of errors in the subjective device setup. This overestimation of rolling resistance increased the power output readings. Conclusion: Accuracy of rolling resistance seems to be very important in determining power output using the PowerPod. When using a rolling resistance based on previous literature, the PowerPod showed high validity when compared with the InfoCrank in a controlled field test (study 1) but less so in a dynamic environment (study 2).

scholarly journals An Analysis of Variability in Power Output During Indoor and Outdoor Cycling Time Trials

2019 ◽  
Vol 14 (9) ◽  
pp. 1273-1279 ◽  
Author(s):  
Owen Jeffries ◽  
Mark Waldron ◽  
Stephen D. Patterson ◽  
Brook Galna
Keyword(s):  
Power Output ◽  
Time Trial ◽  
Mean Power ◽  
Portable Power ◽  
Output Variability ◽  
Competitive Cyclists ◽  
The Mean ◽  
Mean Power Output ◽  
Testing Protocols ◽  
Indoor And Outdoor

Purpose: Regulation of power output during cycling encompasses the integration of internal and external demands to maximize performance. However, relatively little is known about variation in power output in response to the external demands of outdoor cycling. The authors compared the mean power output and the magnitude of power-output variability and structure during a 20-min time trial performed indoors and outdoors. Methods: Twenty male competitive cyclists ( 60.4 [7.1] mL·kg−1·min−1) performed 2 randomized maximal 20-min time-trial tests: outdoors at a cycle-specific racing circuit and indoors on a laboratory-based electromagnetically braked training ergometer, 7 d apart. Power output was sampled at 1 Hz and collected on the same bike equipped with a portable power meter in both tests. Results: Twenty-minute time-trial performance indoor (280 [44] W) was not different from outdoor (284 [41] W) (P = .256), showing a strong correlation (r = .94; P < .001). Within-persons SD was greater outdoors (69 [21] W) than indoors (33 [10] W) (P < .001). Increased variability was observed across all frequencies in data from outdoor cycling compared with indoors (P < .001) except for the very slowest frequency bin (<0.0033 Hz, P = .930). Conclusions: The findings indicate a greater magnitude of variability in power output during cycling outdoors. This suggests that constraints imposed by the external environment lead to moderate- and high-frequency fluctuations in power output. Therefore, indoor testing protocols should be designed to reflect the external demands of cycling outdoors.

scholarly journals Anaerobic energy provision does not limit Wingate exercise performance in endurance-trained cyclists

2003 ◽  
Vol 94 (2) ◽  
pp. 668-676 ◽  
Author(s):  
J. A. L. Calbet ◽  
J. A. De Paz ◽  
N. Garatachea ◽  
S. Cabeza de Vaca ◽  
J. Chavarren
Keyword(s):  
Exercise Performance ◽  
Power Output ◽  
Acute Hypoxia ◽  
Lactate Concentration ◽  
Oxygen Deficit ◽  
Peak Power Output ◽  
Fatigue Index ◽  
Mean Power ◽  
Anaerobic Energy ◽  
Mean Power Output

The aim of this study was to evaluate the effects of severe acute hypoxia on exercise performance and metabolism during 30-s Wingate tests. Five endurance- (E) and five sprint- (S) trained track cyclists from the Spanish National Team performed 30-s Wingate tests in normoxia and hypoxia (inspired O2 fraction = 0.10). Oxygen deficit was estimated from submaximal cycling economy tests by use of a nonlinear model. E cyclists showed higher maximal O2 uptake than S (72 ± 1 and 62 ± 2 ml · kg−1 · min−1, P < 0.05). S cyclists achieved higher peak and mean power output, and 33% larger oxygen deficit than E ( P< 0.05). During the Wingate test in normoxia, S relied more on anaerobic energy sources than E ( P < 0.05); however, S showed a larger fatigue index in both conditions ( P < 0.05). Compared with normoxia, hypoxia lowered O2 uptake by 16% in E and S ( P < 0.05). Peak power output, fatigue index, and exercise femoral vein blood lactate concentration were not altered by hypoxia in any group. Endurance cyclists, unlike S, maintained their mean power output in hypoxia by increasing their anaerobic energy production, as shown by 7% greater oxygen deficit and 11% higher postexercise lactate concentration. In conclusion, performance during 30-s Wingate tests in severe acute hypoxia is maintained or barely reduced owing to the enhancement of the anaerobic energy release. The effect of severe acute hypoxia on supramaximal exercise performance depends on training background.

Power Output and Technique of Wheelchair Athletes

1994 ◽  
Vol 11 (1) ◽  
pp. 71-85 ◽  
Author(s):  
Karin Roeleveld ◽  
Eric Lute ◽  
Dirkjan Veeger ◽  
Luc van der Woude ◽  
Tom Gwinn
Keyword(s):  
Power Output ◽  
Peak Exercise ◽  
Total Force ◽  
Propulsive Force ◽  
Mean Power ◽  
Wheelchair Athletes ◽  
Output Force ◽  
Braking Torque ◽  
The Right ◽  
Mean Power Output

To assess power output, force application, and kinematics of wheelchair propulsion in peak exercise, nine wheelchair athletes with medical lesion levels of T8 or lower performed a 30-s sprint test on a stationary wheelchair ergometer. Mean power output, calculated for the right wheel only, was 59.4 ± 8.5 W. The ratio between effective force and total propulsive force was 60 ± 6%. A negative torque around the hand and a not tangentially directed total force accounted for this low effectiveness. Since the subject group was highly trained, their technique was considered to be optimal for the given circumstances. Therefore, athletes who want to improve power output by increasing effectiveness should keep in mind the existence of a nontangential propulsive force and a braking torque applied by the hands onto the hand rim surface. It is likely that both aspects will be influenced by the geometry of the wheelchair, for example, hand rim dimension or seat position.

scholarly journals Re-esterified DHA improves ventilatory threshold 2 in competitive amateur cyclists

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Vicente Ávila-Gandía ◽  
Antonio Torregrosa-García ◽  
Antonio J. Luque-Rubia ◽  
María Salud Abellán-Ruiz ◽  
Desirée Victoria-Montesinos ◽  
...  
Keyword(s):  
Power Output ◽  
Ventilatory Threshold ◽  
Heart Rate Recovery ◽  
Recovery Phase ◽  
Lactate Clearance ◽  
Mean Power ◽  
Double Blind ◽  
Cycling Test ◽  
Competitive Cyclists ◽  
Mean Power Output

Abstract Background Fish oils were studied as ergogenic aids in a number of mixed physical trial designs showing promising results. However, the heterogeneous purity of the studied supplements, combined with the variety of physical tests employed call for more studies to confirm these findings, ideally with standardised supplements. Our aim was to test a supplement highly concentrated in DHA (DHA:EPA ratio equal to approximately 8:1) on a maximal cycling test to elucidate performance improvements mainly due to DHA. Methods A double-blind, placebo controlled, randomised balanced, parallel design, in competitive amateur cyclists was employed. They were all male, older than 18 years old, with training routine of 2 to 4 sessions per week lasting at least one hour each. A ramp cycling test to exhaustion with a subsequent 5 min recovery phase was employed before and after treatment to analyse aerobic metabolism and lactate clearance after the bout. After 30 days of supplementation with 975 mg of re-esterified DHA, the thirty-eight cyclist who completed the study were finally included for statistical analysis. Results Mean power output at ventilatory threshold 2 (VT2) improved after DHA supplementation both as absolute (△DHA versus △PLA: 6.33–26.54 Watts; CI 95%) and relative (p=0.006) values, paralleled with higher oxygen consumption at VT2 both for absolute (DHA 2729.4 ±304.5, 3045.9 ±335.0; PLA 2792.3 ±339.5, 2845.5 ±357.1; ml·min−1 baseline versus post p=0.025) and relative values (DHA 36.6 ±5.0, 41.2 ±5.4; PLA 37.2 ±5.7, 38.1 ±5.2; ml·kg−1·min−1 baseline versus post p=0.024). Heart rate recovery rate improved during the recovery phase in the DHA group compared to PLA (p=0.005). Conclusion DHA is capable of improving mean power output at the ventilatory threshold 2 (anaerobic ventilatory threshold) in amateur competitive cyclists. It is unclear if these findings are the result of the specific DHA supplement blend or another factor.

Effects of Carbohydrate Ingestion and Carbohydrate Mouth Rinse on Repeat Sprint Performance

2017 ◽  
Vol 27 (3) ◽  
pp. 204-212 ◽  
Author(s):  
Ben M. Krings ◽  
Timothy J. Peterson ◽  
Brandon D. Shepherd ◽  
Matthew J. McAllister ◽  
JohnEric W. Smith
Keyword(s):  
Heart Rate ◽  
Power Output ◽  
Sprint Performance ◽  
Rating Of Perceived Exertion ◽  
Mouth Rinse ◽  
Total Work ◽  
Fatigue Index ◽  
Mean Power ◽  
Carbohydrate Ingestion ◽  
Mean Power Output

The purpose of this investigation was to examine to the influence of carbohydrate ingestion (CHOI) and carbohydrate mouth rinse (CHOR) on acute repeat maximal sprint performance. Fourteen healthy males (age: 21.7 ± 1.8 years, mass: 82.3 ± 12.3 kg) completed a total of five 15-s maximal repeat sprints on a cycle ergometer against 0.075 kg ・ kg-1 body mass each separated by 4 min of active recovery. Subjects completed four experimental trials and were randomly assigned one of four treatments: (1) CHOI, (2) CHOR, (3) placebo mouth rinse (PLAR), (4) placebo ingestion (PLAI). Subjects rinsed or ingested six 50 mL 10% CHO solutions throughout each trial. Performance variables measured included rating of perceived exertion, peak heart rate, peak and mean power output, fatigue index, and total work. Significant treatment main effects were observed for mean power output (p = 0.026), total work (p = 0.020), fatigue index (p = 0.004), and heart rate (p = 0.013). Overall mean power output and total work were significantly greater with CHOI (659.3 ± 103.0 watts, 9849.8 ± 1598.8 joules) compared with CHOR (645.8 ± 99.7 watts, 9447.5 ± 1684.9 joules, p < .05). CHOI (15.3 ± 8.6 watts/s) significantly attenuated fatigue index compared with CHOR (17.7 ± 10.4 watts/s, p < .05). Based on our findings, CHOI was more likely to provide a beneficial performance effect compared with CHOR, PLAI, and PLAR. Athletes required to complete repeat bouts of high intensity exercise may benefit from CHOI.

Variability in Power Output During Cycling in International Olympic-Distance Triathlon

2014 ◽  
Vol 9 (4) ◽  
pp. 732-734 ◽  
Author(s):  
Naroa Etxebarria ◽  
Shaun D’Auria ◽  
Judith M. Anson ◽  
David B. Pyne ◽  
Richard A. Ferguson
Keyword(s):  
Body Mass ◽  
Power Output ◽  
Coefficient Of Variation ◽  
Aerobic Power ◽  
Maximal Aerobic Power ◽  
Mean Power ◽  
Large Power ◽  
Elite Level ◽  
The Mean ◽  
Mean Power Output

Purpose:The patterns of power output in the ~1-h cycle section of Olympic-distance triathlon races are not well documented. Here the authors establish a typical cycling-race profile derived from several International Triathlon Union elite-level draftinglegal triathlon races.Methods:The authors collated 12 different race power profiles from elite male triathletes (N = 5, age 25 ± 5 y, body mass 65.5 ± 5.6 kg; mean ± SD) during 7 international races. Power output was recorded using SRM cranks and analyzed with proprietary software.Results:The mean power output was 252 ± 33 W, or 3.9 ± 0.5 W/kg in relative terms, with a coefficient of variation of 71% ± 13%. Normalized power (power output an athlete could sustain if intensity were maintained constant without any variability) for the entire cycle section was 291 ± 29 W, or 40 ± 13 W higher than the actual mean power output. There were 34 ± 14 peaks of power output above 600 W and ~18% time spent at >100% of maximal aerobic power.Conclusion:Cycling during Olympic-distance triathlon, characterized by frequent and large power variations including repeat supramaximal efforts, equates to a higher workload than cycling at constant power.

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