Where is the actual performance data for situational power output for clipless and flats? I have run across some articles on the web but nuthin super scientific.
You sound like you have seen some solid numbers. Do tell…
All the Best,
Thanks for writing. I sometimes wonder how your riding has been since our clinic in Crested Butte, what, three years ago?
Real numbers are hard to find. The studies are all road-focused, on indoor trainers, which leaves out many variables important to us MTBers. This is an area I obsess over often; I dearly want a power meter so I can conduct studies of my own. Lee Likes Science dot com!
In the mean time …
Our friend Greg Romero coached Jill Kintner and Mike Day to their Olympic BMX medals. Greg is my source for training and sprinting technique in the upcoming book Pro BMX Skills. Let’s call Greg the world’s leading authority on training and sprint technique for BMX.
Greg believes strongly in the power of the downstroke. He believes athletes should focus almost exclusively on pushing down on the pedals. He says worrying about the rest of the stroke actually inhibits your power. Think what you like, but Greg has data!
Greg Romero’s experiment
Rider: 17-year-old Expert BMX racer
Bike: Road bike with an SRM Professional Power Meter, 172.5mm cranks, 50.5-inch gear
Protocol: Stand-start sprint in the drops for five full cranks (the average distance to the first jump on a BMX track)
Round 1: 4 sprints focusing on the downstroke
Round 2: 4 sprints with the same downstroke, but focusing on using the upstroke
Round 3: 4 sprints with flat pedals
|Variable||Peak power||Peak cadence||Max. speed|
|Clipped in – Downstroke||1,426 watts||122 rpm||19.2 mph|
|Clipped in – Upstroke||1,241 watts||108 rpm||17.9 mph|
|Flat pedals||1,165 watts||118 rpm||18.2 mph|
There are a zillion variables, so this isn’t perfect science, but:
– Clips produce more power than flats. Greg says that’s not because you’re “pedaling circles,” but because clips control your feet and let you focus on a more powerful downstroke.
– A good stroke on flats is faster than an awkward stroke clipped in.
This area is fascinating to me, and I hope to someday develop solid numbers.
Read Greg’s article here.
The human factor is huge — especially off road. If you like clips, rock ’em. If you prefer flats, rock those.
Looking for a power-meter sponsor … 🙂
BTW: Go out and do five pedal strokes from a dead stop. Do you hit 19 mph? I’ll bet not!