As far as scientific testing goes downhill mountain bikers aren’t your usual customers and my email is hardly full of requests from downhill riders to get their power levels tested.
So when the discussion came up earlier this year with the guys from Green to Gold race development about testing their physiological characteristics I really had to go back to the drawing board and try and decide what information was going to be valuable to us. With any form of physiological testing the first thing that needs to be done is a task analysis, what is the event? How long does it last? What are the demands? What does it take to win?
Task: get your bike down the hill as fast as possible and preferably stay upright!
Physiological demands: A fast sprint off the line, quick pedal strokes leading into obstacles, 1-2 pedal sections usually lasting less than 10 seconds, accelerations out of corners.
A brief summary I know! But you get the gist!
Note: Downhill mountain biking requires a whole range of skills outside of the leg strength and cycling power, these are tested in other ways outside of this review.
Basically this is an event that requires a huge amount of skill and an unknown amount of power. Based on the time of the event and the limited pedaling time involved in any single run we can assume that the majority of the power produced by a downhill mountain biker is anaerobic in nature and probably comes from a combination of our two anaerobic energy systems. These being the ATP-PC and anaerobic-glycolytic energy systems. The ATP-PC systems produces the largest amount of power but it can be sustained for only a very short period of time <10 seconds, whereas the anaerobic-glycolytic energy system produces slightly less power but it can be sustained for a longer time frame roughly 2 minutes.
Based on the above assumption and the physiological demands described earlier I decided that a battery of 3 tests would provide the basis for our physiological testing. The three tests that I chose were,
- 10 second peak power test
- 30 second wingate test
- 6 x 3 seconds repeat sprint test
Test explanation and justification
10 second peak power test: The 10 second peak power test was designed to replicate the out of the gate sprint, on course pedaling section and potential sprint for the line. It represents the upper limit of time that an athlete would be pedaling for out on course. I was looking for an athlete that could produce large amounts of power and sustain it over the 10 second test period. This test will place a huge demand on the neuromuscular system as well as the ATP-PC without fatiguing the anaerobic glycolytic system.
30 second Wingate test: The Wingate test is commonly used in a wide range of physiology labs around the world as a measure of anaerobic capacity. It places a large amount of stress on the anaerobic-glycolytic system and we are really looking for the athlete who is able to maintain their power output for the entire 30 seconds. Although this test is longer than almost all pedaling sections in a downhill mountain bike race it provides valuable information about an athlete’s anaerobic capacity.
6 x 3 second repeat sprint test: This test has its background in BMX racing however it shares valuable characteristics with downhill mountain biking specifically we are looking at an athlete’s ability to produce large power outputs in a very short time span at high cadence, recover, repeat. This test perhaps most closely mimics the specific demands of downhill racing. The test protocol places huge demand on the neuromuscular system, ATP-PC system and Anaerobic-glycolytic energy system. As the entire test lasts 3 minutes including the rest period.
Without giving too much away about individual athletes and their results here is some overview data
10 second peak power test:
- Peak power: 1896 Watts
- Average power: 1496 Watts
- Cadence: 128 RPM
- Peak Power: 1783 Watts
- Average Power: 1165 Watts
- Cadence: 122
6 x 3 second Sprint:
- Peak power: 1830 Watts
- Minimum power: 1781 Watts
These guys are serious athletes!!! These numbers are on par with a lot of sprinters. Not only do these guys smash round corners, cruise rock gardens and get air that birds would be proud of they also produce serious power. Further on the bike research needs to be done to compare the stationary bike powers to those that are produced out on course. This will provide myself and the guy’s far greater insight into the specific demands of an individual course and what it takes to win.
For more information on the physiological demands of downhill racing check out this review article