In an effort to settle the flats-vs-clips argument, GMBN headed to the test lab (click to enlarge).
There are a number of arguments that constantly reoccur in our forums: 1x vs. 2x drivetrains, Shimano vs. all other brakes, and of course clips vs. flat pedals. While most mountain bikers opt to ride clipped in, the Mtbr staff is split down the middle. Gregg and Jason prefer clips. Francis and I usually ride flats. So how much efficiency are we sacrificing due to our choice in pedal?
To find out we turn to the crew at the Global Mountain Biking Network, who took to the lab at the U.K.'s University of Bath to measure several metrics including power output, heart rate, V02 max, and blood lactate. Each test consisted of professional rider and show host Neil Donoghue keeping a consistent 16.7mph pace on a treadmill using both types of pedals. For the first test, the gradient was set at 2% and Donoghue pedaled for a period of 10 minutes. The second test was designed to emulate a short hard sprint, so the gradient was set at 8% and Donoghue laid down the power for a minute and a half.
The end results were surprising. As you might have guessed, clips were more efficient over longer distances, but not by a huge margin. Donoghue's V02 max and lactate levels were marginally lower over a 10-minute period when clipped in, but his heart rate was comparable regardless of pedal choice.
For the second test, which mimicked a short hard sprint, Donoghue's V02 max and lactate were lower on flat pedals, although his heart rate was much higher. So while he wasn't working as hard when clipped in (as evidenced by his lower heart rate), he was using more oxygen and producing more lactate. The GMBN crew speculates this is because his body was engaging more muscles and his cadence was different when clipped in.
This video offers some interesting insights into the classic flats vs. clipless argument, but we'd be curious to see the tests performed again with a larger sample group. Until then the debate will rage on. Check out the video and then let us know what you think in the comments section below.