Accuracy of SRM and Power Tap Power Monitoring Systems for Bicycling

Gardner, Andrew S.; Stephens, Shaun; Martin, David T.; Lawton, E.; Lee, Hamilton; Jenkins, David G.

doi:10.1249/01.mss.0000132380.21785.03

Cited by 156 publications

(154 citation statements)

References 13 publications

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“…Participants' road bikes were equipped with a PowerTap Elite wheel (CycleOps, Madison, USA) and a magnet for direct cadence measurement (Gardner et al 2004). For the laboratory tests, the same road bike was attached to a Computrainer (RacerMate, Seattle, USA).…”

Section: Methodsmentioning

confidence: 99%

“…The PowerTap device was zero offset prior to all trials according to the manufacturer's instructions (Gardner et al 2004 When cadence dropped by more than 10 rev·min -1 for more than 10 s despite strong verbal encouragement, tests were terminated. Expired gases were collected continuously throughout the test using a Cortex MetaLyzer 3B gas analyser (Cortex Biophysik, Leipzig, Germany).…”

Section: Methodsmentioning

confidence: 99%

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Validity and reliability of critical power field testing

et al. 2014

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2 2 ABSTRACT Purpose: To test the validity and reliability of field critical power (CP). Method: Laboratory CP tests comprised of three exhaustive trials at intensities of 80%, 100% and 105% maximal aerobic power and CP results were compared with those determined from the field. Experiment 1: cyclists performed three CP field tests which comprised maximal efforts of 12 min, 7 min and 3 min with a 30 min recovery between efforts. Experiment 2: cyclists performed 3 x 3 min, 3 x 7 min and 3 x 12 min individual maximal efforts in a randomised order in the field. Experiment 3: the highest 3 min, 7 min and 12 min power outputs were extracted from field training and racing data. Results:Standard error of the estimate of CP was 4.5%, 5.8% and 5.2% for experiments 1-3 respectively.Limits of Agreement for CP were -26 -29 W, 26 -53 W and -34 -44 W for experiments 1-3 respectively. Mean coefficient of variation in field CP was 2.4%, 6.5% and 3.5 % for experiments 1-3 respectively. Intraclass correlation coefficients of the three repeated trials for CP were 0.99, 0.96 and 0.99 for experiments 1-3 respectively. Conclusions: Results suggest field-testing using the different protocols from this research study, produce both valid and reliable CP values.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Validity and reliability of critical power field testing

et al. 2014

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“…Prior to providing written informed consent and participation, cyclists were fully informed of the nature and risks of the study. A road bicycle equipped with a PowerTap Elite wheel (CycleOps, Madison, USA) was used to measure work in both laboratory and field tests [15]. The saddle and handlebar were adjusted to suit each participant and settings were replicated exactly during subsequent tests.…”

Section: Subjectsmentioning

confidence: 99%

High Agreement between Laboratory and Field Estimates of Critical Power in Cycling

et al. 2013

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Karsten, B., Jobson, S. A., Hopker, J., Jimenez, A., Beedie, C. (2014). High Agreement between Laboratory and Field Estimates of Critical Power in Cycling. International Journal of Sports Medicine, 35 (4), 298-303The purpose of this study was to investigate the level of agreement between laboratory-based estimates of critical power (CP) and results taken from a novel field test. Subjects were fourteen trained cyclists (age 40 +/- 7 yrs; body mass 70.2 +/- 6.5 kg; O-2max 3.8 +/- 0.5 L center dot min(-1)). Laboratory-based CP was estimated from 3 constant work-rate tests at 80%, 100% and 105% of maximal aerobic power (MAP). Field-based CP was estimated from 3 all-out tests performed on an outdoor velodrome over fixed durations of 3, 7 and 12 min. Using the linear work limit (W-lim) vs. time limit (T-lim) relation for the estimation of CP1 values and the inverse time (1/t) vs. power (P) models for the estimation of CP2 values, field-based CP1 and CP2 values did not significantly differ from laboratory-based values (234 +/- 24.4 W vs. 234 +/- 25.5 W (CP1); PpublishersversionPeer reviewe

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“…Power output was measured directly and continuously at the ergometer's back wheel using a PowerTap hub (14,30). Gross efficiency was calculated at each work rate as follows: gross efficiency (%) ϭ 100% ϫ (work done/metabolic cost).…”

Section: Methodsmentioning

confidence: 99%

Endurance exercise training blunts the deleterious effect of high-fat feeding on whole body efficiency

Edwards

Holloway

Murray

et al. 2011

American Journal of Physiology-Regulatory, Integrative and Comp

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FASEB J 25: 1088FASEB J 25: -1096FASEB J 25: , 2011. To test if a similar dietary regime would blunt whole body efficiency in endurance-trained men and, as a consequence, hinder aerobic exercise performance, 16 endurance-trained men were given a short-term, high-fat (70% kcal from fat) and a moderate carbohydrate (50% kcal from carbohydrate) diet, in random order. Efficiency was assessed during a standardized exercise task on a cycle ergometer, with aerobic performance assessed during a 1-h time trial and mitochondrial function later measured using 31 P-magnetic resonance spectroscopy. The subjects then underwent a 2-wk wash-out period, before the study was repeated with the diets crossed over. Muscle biopsies, for mitochondrial protein analysis, were taken at the start of the study and on the 5th day of each diet. Plasma fatty acids were 60% higher on the high-fat diet compared with moderate carbohydrate diet (P Ͻ 0.05). However, there was no change in whole body efficiency and no change in mitochondrial function. Endurance exercise performance was significantly reduced (P Ͻ 0.01), most probably due to glycogen depletion. Neither diet led to changes in citrate synthase, ATP synthase, or mitochondrial uncoupling protein 3. We conclude that prior exercise training blunts the deleterious effect of short-term, high-fat feeding on whole body efficiency.exercise; magnetic resonance; nutrition; mitochondria THE MAXIMUM EXTERNAL WORK rate that can be sustained by a muscle or group of muscles is determined by the rate at which adenosine triphosphate (ATP) can be supplied to the myofibrils, with the overwhelming majority of ATP used during sustained exercise being derived from oxidative phosphorylation at the mitochondria. The maximum sustainable rate of mitochondrial ATP supply is, in turn, dependent on the rate of delivery of oxygen and reduced intermediates to the respiratory chain and the mitochondrial phosphorylation-to-oxidation ratio, which describes the economy of energy transduction.The major metabolic fuel sources used by the muscle cell to generate reduced intermediates, and thus ATP, are glucose and fatty acids, with substrate preference being determined by different circumstances. For example, glucose oxidation is stoichiometrically more oxygen efficient than fat oxidation (16), and glycogen breakdown is able to supply ATP at a faster rate than other substrates (32), making it the best fuel when a high sustainable power is required or when oxygen supply is limited. However, energy yield per mole of glucose is low compared with fatty acids, as is the body's total storage capacity for glycogen and glucose (32); thus, in situations in which energetic demands are submaximal but prolonged, and when oxygen is plentiful, fatty acids are the preferred choice.Moreover, free fatty acids (FFA) acutely increase proton leak in isolated mitochondria (33), dissipating the proton gradient as heat, and decreasing the phosphorylation-to-oxidation ratio to a greater extent than that expected from a substrate switch alone. ...

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Accuracy of SRM and Power Tap Power Monitoring Systems for Bicycling

Cited by 156 publications

References 13 publications

Validity and reliability of critical power field testing

Validity and reliability of critical power field testing

High Agreement between Laboratory and Field Estimates of Critical Power in Cycling

Endurance exercise training blunts the deleterious effect of high-fat feeding on whole body efficiency

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