Research study - 26-04-2010
The validity and reliability of the iBike power meter
Dr. James Hopker, Dr. Simon Jobson, Dr. Damian Coleman, Dr. Helen Carter
Participant Information Sheet
A research study is being conducted at the University of Kent to investigate the validity and reliability of the new iBike cycling power meter.
Background
A cycling power meter measures the power output of a cyclist and enables them to specifically train to target various physiological parameters. The recent advent of the mobile power meter enables athletes to accurately use power output as a quantitative and accurate method to monitored their training and race performances in field conditions. The new iBike Pro power meter is different from conventional systems in that it does not estimate power output from force applied by the cyclists to part of the drive chain (i.e. crank system or chain system). Instead, the iBike is the first power meter that measures the resistive forces working against the cyclist estimated from frontal surface area, wind resistance, rolling resistance, acceleration, etc. using the equations of motion of a cyclist (di Prampero et al., 1979; Martin et al., 1998).
There are many portable power measuring devices on the market claiming to accuracy measure power output. However, upon investigation, several have shown to overestimated or underestimated readings compared to a criterion measure. The amount of error with a piece of measurement equipment has a significant influence on the degree to which training and racing intensities can be accurately monitored and quantified. A large amount error in the iBike would limit the ability of the cyclist to compare repeated training sessions over any given time period and might challenge the ability to track physiological parameters such as exercise thresholds, heart rate zones and corresponding power output. For these reasons, it is the intention of this research study to evaluate the validity and reliability of the iBike power meter in comparison to the ‘gold standard’ SRM power meter.
What will you be required to do?
University of Kent
All participants will be required to attend the exercise testing laboratory at the University of Kent on one occasion for a test of their maximal aerobic capacity and analysis of frontal surface area. Frontal surface area is required to essentially correct the SRM data for aerodynamic drag and air density which the iBike will routinely perform during its data collection. Photographs will be taken of you on your bike in each of the three positions; dropped, hoods and aerodynamic. This will then be compared to a photograph of a reference rectangle with a known area. The contour of you on your bicycle and that of the rectangle will then be cut out and weighed. Your frontal surface area is estimated by comparing the masses of the pictures of you on your bicycle and that of the reference area.
All participants will then be required to perform a test of maximal aerobic power on a laboratory cycle ergometer. The aim of this test is to determine your maximal level of oxygen uptake (VO2max) and maximal power output. After a 10 minute warm-up at 150W, the test will have an incremental protocol starting at 150W and increasing by 25W every minute until volitional exhaustion. Exhaustion will be defined as the moment that you are no longer capable of turning the pedals on the ergometer.
Preston Park Veldrome
All participants will then be required to attend Preston Park Velodrome (Preston Drove, Brighton) on one occasion (date to be confirmed). You will be required to complete laps of the track on a customizable racing bicycle fitted with the iBike and SRM powermeters in each of three positions (hoods, drops and aero). Power outputs will be set at 150, 200, 250, 300 and 350W. Finally 1 all out sprint lap will be conducted. Power output and cadence data will be recorded concurrently on both powermeters. You will be required to keep your cadence at 90 rpm.
To participate in this research you must: - be a competitive male cyclist and be involved in regular training and racing over the past 3 years - be aged 18–55 years - be a non-smoker - not be taking any medications (for high cholesterol, high blood pressure, etc.) - have no known heart condition or diabetes.
Prior to testing you will be asked to follow these criteria: - No food within 12 hours of testing - Drink ONLY WATER in the morning of testing - No alcohol within 24 hours - Not to be taking any medication for preceding 4 weeks - Free from dietary supplementation (vitamins etc.) for the preceding 4 days - Free from illness/infection during the preceding 2 weeks
Feedback
If required you will receive written feedback of your maximal test results outlining your training intensities. Included within this will be training advice and an offer of future testing if this is likely to benefit your training.
Confidentiality All measurements (data) and personal information will be stored securely within Centre for Sport Studies premises in accordance with the Data Protection Act 1998 and the University’s own data protection requirements. Data can only be accessed by the researchers named above. After completion of the study, all data will be made anonymous (i.e. all personal information associated with the data will be removed).
Deciding Whether to Participate
If you have any questions or concerns about the nature, procedures or requirements for participation do not hesitate to contact me. Should you decide to participate, you will be free to withdraw at any time without having to give a reason. Any Questions? Please contact Dr. James Hopker on 01634 888814 or email j.g.hopker@kent.ac.uk Centre for Sport Studies, University of Kent at Medway, The Medway Building, Chatham Maritime, Chatham, ME4 4AG.
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