The Validity of Power Output Recorded During Exercise Performance Tests Using a Kingcycle Air-Braked Cycle Ergometer When Compared With an SRM Powermeter

This study assessed the validity of power output recorded using an air-braked cycle ergometer (Kingcycle™) when compared with a power measuring crankset (SRM™). For part one of the study thirteen physically active subjects completed a continuous incremental exercise test (OBLA), for part two of the study twelve trained cyclists completed two tests; a maximal aerobic power test (MAP) and a 16.1 km time-trial (16.1 km TT). The following were compared; the peak power output (PPO) recorded for 1 min during MAP, the average power output for the duration of the time-trial and power output recorded during each stage of OBLA. For all tests, power output recorded using Kingcycle was significantly higher than SRM (P < 0.001). Ratio limits of agreement between SRM and Kingcycle for OBLA showed a bias (P < 0.00) of 0.90 (95 %CI = 0.90 - 0.91) with a random error of ×/÷ 1.07, and for PPO and 16.1 km TT ratio limits of agreement were 0.90 (95 %CI = 0.88 - 0.92) ×/÷ 1.07 and 0.92 (95 %CI = 0.90 - 0.94) ×/÷ 1.07, respectively. This data revealed that the Kingcycle ergometry system did not provide a valid measure of power output when compared with SRM.

Key words:

Validity - measurement error - cycling - time trial - peak power output

References

• 1 Atkinson G, Nevill A M. Statistical methods for assessing measurement error (reliability) in variables relevant to sports medicine.  Sports Med. 1998;  26 217-236
• 2 Bland J M, Altman D G. Statistical methods for assessing agreement between two methods of clinical measurement.  Lancet. 1986;  I 307-310
• 3 Cohen L, Holiday M. Statistics for Social Scientists. London; Harper & Row Ltd 1983: 97-110
• 4 Coyle E F, Feltner M E, Kautz S A, Hamilton M T, Montain S J, Baylor A M, Abraham L D, Petrek G W. Physiological and biomechanical factors associated with elite endurance cycling performance.  Med Sci Sports Exerc. 1991;  23 93-107
• 5 El-Sayed M S, Balmer J, Rattu A JM. Carbohydrate ingestion improves endurance performance during 1 h simulated cycling time-trial.  J Sports Sci. 1997;  15 223-230
• 6 Hawley J A, Noakes T D. Peak power output predicts maximal oxygen uptake and performance time in trained cyclists.  Eur J Appl Physiol. 1992;  65 79-83
• 7 Hawley J A, Palmer G S, Noakes T D. Effects of 3 days of carbohydrate supplementation on muscle glycogen content and utilisation during one hour cycling performance.  Eur J Appl Physiol. 1997;  75 407-412
• 8 Jeukendrup A, van Diemen A. Heart rate monitoring during training and competition in cyclists.  J Sport Sci. 1998;  16 99
• 9 Jones S M, Passfield L. The dynamic calibration of bicycle power measuring cranks. In: Haake SJ (ed) The Engineering of Sport. Oxford; Blackwell Science 1998: 265-274
• 10 Keen P S, Passfield L, Hale T. Indirect determination of V˙O₂max using a sports-specific (cycle) ergometer system (Abstract).  J Sports Sci. 1991;  9 420
• 11 Lindsay F H, Hawley J A, Myburgh K H, Schomer H H, Noakes T D, Dennis S C. Improved athletic performance in highly trained cyclists after interval training.  Med Sci Sports Exerc. 1996;  28 1427-1434
• 12 Lucia A, Pardo J, Durantez A, Hoyos J, Chicharro J L. Physiological differences between professional and elite road cyclists.  Int J Sports Med. 1998;  19 342-348
• 13 Martin J C, Milliken D L, Cobb J E, McFadden K L, Coggan A R. Validation of a mathematical model for road cycling power.  J Appl Biomech. 1998;  14 276-291
• 14 Padilla S, Mujika I, Cuesta G, Goiriena J J. Level ground and uphill cycling ability in professional road cycling.  Med Sci Sports Exerc. 1999;  31 878-885
• 15 Palmer G S, Dennis S C, Noakes T D, Hawley J A. Assessment of the reproducibility of performance testing on air-braked cycle ergometer.  Int J Sports Med. 1996;  4 293-298
• 16 Palmer G S, Noakes T D, Hawley J A. Effects of steady-state versus stochastic exercise on subsequent cycling performance.  Med Sci Sports Exerc. 1997;  29 684-687
• 17 Palmer G S, Clancy M C, Hawley J A, Rodger I M, Burke L M, Noakes T D. Carbohydrate ingestion immediately before exercise does not improve 20 km time-trial performance in well trained cyclists.  Int J Sports Med. 1998;  19 415-418
• 18 Robinson T A, Hawley J A, Palmer G S, Wilson G R, Gray D A, Noakes T D, Dennis S C. Water ingestion does not improve 1 h cycling performance in moderate ambient temperatures.  Eur J Appl Physiol. 1995;  71 153-160
• 19 Schabort E J, Hawley J A, Hopkins W G, Mujika I, Noakes T D. A new reliable laboratory test of endurance performance for road cyclists.  Med Sci Sports Exerc. 1998;  30 1744-1750
• 20 Stepto N K, Hawley J A, Dennis S C, Hopkins W G. Effect of different interval-training programs on cycling time-trial performance.  Med Sci Sports Exerc. 1999;  31 736-741
• 21 Van Praagh E, Bedu M, Roddier P, Coudert J. A simple calibration method for mechanically braked cycle ergometers.  Int J Sports Med. 1992;  13 27-30
• 22 Westgarth-Taylor C, Hawley J A, Rickard S, Myburgh K H, Noakes T D, Dennis S C. Metabolic and performance adaptations to interval training in endurance-trained cyclists.  Eur J Appl Physiol. 1997;  75 298-304
• 23 Weston A R, Myburgh K H, Lindsay F H, Dennis S C, Noakes T D, Hawley J A. Skeletal muscle buffering capacity and endurance performance after high-intensity interval training by well-trained cyclists.  Eur J Appl Physiol. 1997;  75 7-13
• 24 Wilber R L, Zawadzki K M, Kearnet J T, Shannon M P, Disalvo D. Physiological profiles of elite off-road and road cyclists.  Med Sci Sports Exerc. 1997;  29 1090-1094
• 25 Zhu W. Making bootstrap statistical inferences: a tutorial.  Res Q Exerc Sport. 1997;  68 44-55