PWC-170 Cycle Test

The objective of the PWC-170 test is to predict the power output(watts) at a projected heart rate of 170 beats per minute(bpm).

Required resources

To undertake this test you will require:

• Bicycle ergometer
• Heart rate monitor
• Stop watch
• Assistant.

How to conduct the test

The athlete performs two consecutive six minute bicycle ergometer rides in which the work loads are selected to produce a heart rate between 120 and 140 bpm on the first session and 150 and 170 bpm on the second session. For each session the average Heart Rate(bpm) and Power Output(watts) are recorded.

Analysis

Analysis of the result is by comparing it with the results of previous tests. It is expected that, with appropriate training between each test, the analysis would indicate an improvement.

Calculations

• Use a graph to plot the two points: X axis = Power(Watts) and Y axis = Heart Rate(bpm). Draw a straight line through the two points so that it is extended to 170 bpm.
• Draw a perpendicular line from the point plotted at a heart rate of 170 bpm to the X axis.
• Read off the projected power output at this point.

An alternative mathematical approach to determining the power output at 170 bpm is the Polynomial Approximation method.

• Power output = ((P1 x HR2) – (P2 x HR1)) / (HR2 – HR1) + (170 x ((P1 – P2) / (HR1 – HR2)))

Where:

• P1 = Power(watts) for session 1
• P2 = Power(watts) for session 2
• HR1 = heart rate for session 1
• HR2 = heart rate for session 2

Example:

An athlete produces the following test results:

• Session 1 – average heart rate of 130 bpm at 100 watts(600 kg/minute)
• Session 2 – average heart rate of 153 bpm at 150 watts(900 kg/minute)
• The predicted power output at 170 bpm is approximately 187 watts.

Power Output = ((100 x 153) – (150 x 130)) / (153 – 130) + (170 x ((100 – 150) / (130 – 153)))

Power Output = (15300 – 19500) / 23 + (170 x (-50 / -23))

Power Output = -182.6 + 369.57

Power Output = 186.96 watts

Target group

This test is suitable for sprint cyclists and sprinters but not for individuals where the test would be contraindicated.

Reliability

Reliability would depend upon how strict the test is conducted and the individual’s level of motivation to perform the test.

Validity

There are no published tables to relate results to potential performance in competition.