Validity and Reliability of the Wattbike Cycle Ergometer

Abstract

The purpose of this study was to assess the validity and reliability of the Wattbike cycle ergometer against the SRM Powermeter using a dynamic calibration rig (CALRIG) and trained and untrained human participants. Using the CALRIG power outputs of 50–1 250 W were assessed at cadences of 70 and 90 rev.min⁻¹. Validity and reliability data were also obtained from 3 repeated trials in both trained and untrained populations. 4 work rates were used during each trial ranging from 50–300 W. CALRIG data demonstrated significant differences (P<0.05) between SRM and Wattbike across the work rates at both cadences. Significant differences existed in recorded power outputs from the SRM and Wattbike during steady state trials (power outputs 50–300 W) in both human populations (156±72 W vs. 153±64 W for SRM and Wattbike respectively; P<0.05). The reliability (CV) of the Wattbike in the untrained population was 6.7% (95%CI 4.8–13.2%) compared to 2.2% with the SRM (95%CI 1.5–4.1%). In the trained population the Wattbike CV was 2.6% (95%CI 1.8–5.1%) compared to 1.1% with the SRM (95%CI 0.7–2.0%). These results suggest that when compared to the SRM, the Wattbike has acceptable accuracy. Reliability data suggest coaches and cyclists may need to use some caution when using the Wattbike at low power outputs in a test-retest setting.

Key words

cycling - ergometry - calibration - power output - testing - talent identification

References

• 1 Abbis CR, Quod MJ, Levin G, Martin DT, Laursen PB. Accuracy of the Velotron ergometer and SRM power meter.  Int J Sports Med. 2009;  30 107-112
• 2 Balmer J, Davison RCR, Bird SR. Peak power predicts performance power during an outdoor 16.1-km cycling time trial.  Med Sci Sports Exerc. 2000;  32 1485-1490
• 3 Bertucci W, Duc S, Villerius V, Pernin JN, Grappe F. Validity and reliability of the PowerTap mobile cycling Powermeter when compared with the SRM device.  Int J Sports Med. 2005;  26 868-873
• 4 Bland JM, Altman DG. Statistical methods for assessing agreement between 2 methods of clinical measurement.  Lancet. 1986;  1 307-310
• 5 Gardner AS, Stephens S, Martin DT, Lawton E, Lee H, Jenkins D. Accuracy of SRM and Power Tap power monitoring systems for bicycling.  Med Sci Sports Exerc. 2004;  36 1252-1258
• 6 Harriss DJ, Atkinson G. International Journal of Sports Medicine – Ethical Standards in Sport and Exercise Science Research.  Int J Sports Med. 2009;  30 701-702
• 7 Hopkins W, Hawley JA, Burke LM. Design and analysis of research on sport performance enhancement.  Med Sci Sports Exerc. 1999;  31 472-485
• 8 Hopkins W. Measures of reliability in sports medicine and science.  Sports Med. 2000;  30 1-15
• 9 Hopkins WG, Schabort EJ, Hawley JA. Reliability of power in physical performance tests.  Sports Med. 2001;  31 211-234
• 10 Jones SM, Passfield L. The dynamic calibration of bicycle power measuring cranks. In: Haake SJ (ed.) The Engineering of Sport. Oxford: Blackwell; 1998: 265-274
• 11 Kirkland A, Coleman D, Wiles JD, Hopker J. Validity and reliability of the Ergomo pro Powermeter.  Int J Sports Med. 2008;  29 913-916
• 12 Martin JC, Milliken DL, Cobb JE, McFadden KL, Coggan AR. Validation of a mathematical model for road cycling power.  J Appl Biomech. 1998;  14 276-291
• 13 Maxwell BF, Withers RT, Ilsley AH, Wakim MJ, Woods GF, Day L. Dynamic calibration of mechanically, air- and electromagnetically braked cycle ergometers.  Eur J Appl Physiol. 1998;  78 346-352
• 14 Nevill AM. Why the analysis of performance variables recorded on a ratio scale will invariably benefit from a log transformation (editorial).  J Sports Sci. 1997;  15 457-458
• 15 Paton C, Hopkins W. Tests of cycling performance.  Sports Med. 2001;  31 489-496
• 16 Russell JC, Dale JB. Dynamic torquemeter calibration of bicycle ergometers.  J Appl Physiol. 1986;  61 1217-1220
• 17 Wooles AL, Robinson AJ, Keen PS. A static method for obtaining a calibration factor for SRM bicycle power cranks.  Sports Eng. 2005;  8 137-144
• 18 Wilmore JH, Constable SH, Stanforth PR, Buono MJ, Tsao YW, Roby FB, Lowdon BJ, Ratliff RA. Mechanical and physiological calibration of 4 cycle ergometers.  Med Sci Sports Exerc. 1982;  14 322-325

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