Clipless Pedals: Do You Pull Up?

Clip-in pedals (called "clipless" because they replaced the old toe clips and straps) are not a pulling machine. Here is what they actually do, in 3D.

A cleat under the shoe locks into the pedal, so the foot stays attached through the whole pedal circle. The power still comes from pushing down and forward. On the rising side, a large part of the force on the pedal is simply the weight and swing of the leg itself, not a pull. Clipped in, you also get options a flat pedal can't give you: pull back through the bottom, ease off the rising pedal instead of dragging it down, and keep your foot on at full power. On a flat pedal, pull up and the foot leaves it.

But the clip does not add force. In lab studies, deliberately pulling up on the upstroke raised mechanical effectiveness and lowered efficiency, and in steady submaximal riding clipless and flat pedals did not differ significantly in effectiveness or efficiency. What the clip gives you is control, and the choice.

In this 3D model the force arrows illustrate a typical stroke (relative size only, no measured values), and the hip flexors that lift the leg are not shown.

Muscles lit: quadriceps, glutes, hamstrings, calves.

Sources: • Mornieux G, Stapelfeldt B, Gollhofer A, Belli A. Effects of pedal type and pull-up action during cycling. Int J Sports Med. 2008;29(10):817-822. doi:10.1055/s-2008-1038374 • Korff T, Romer LM, Mayhew I, Martin JC. Effect of pedaling technique on mechanical effectiveness and efficiency in cyclists. Med Sci Sports Exerc. 2007;39(6):991-995. doi:10.1249/mss.0b013e318043a235 • Kautz SA, Hull ML. A theoretical basis for interpreting the force applied to the pedal in cycling. J Biomech. 1993;26(2):155-165. doi:10.1016/0021-9290(93)90046-h