The Science Behind a Great Pedal Stroke 

as a motorcycle mechanic, this sounds like a inline twin 2 stroke engine, something to get in my mind when riding my bicycle now

This totally explains the effect of too long of a crank that I was feeling. With 175s (I’m 5’7”), I always felt it difficult to get stroke started and started at 1230 or 1 instead of 11 that I can do with 165s. I also feel like I’m able to extend the stroke deeper into the 7 o’clock position. My circle is more circular instead of eccentric

Worked on this for the last month ,. Definitely focusing better trying in synchro 11-1, 5-7 . I Improved power and cadence +++ . Thanks soo much…

Brother Charlie! How great to see you on your first Podcast in your zone of genius. You are a natural and a wealth of knowledge! ❤

Charlie Charlie !!! You are the best thank you for all your advise always pedaling. Thank you Adam for inviting him. You both are a great team !!

Great presentation. Charlie I still remember how you helped me with cadence and pedal stroke 11 years ago climbing Squaw Pass on our way to Mt. Evans. Thanks again, I'm still learning and improving. Ken

My imagery is to to think of the crank/BB as a pepper mill (with the old little hand crank on top) and to think about grinding pepper with my legs. Been doing this since the 1990's and now its just natural. In fact I've had other cyclists ask how I've developed big hamstrings for cycling.

As a BKA (below knee amputation) of one side), this explains the lose of symmetrical force balance, which is not huge. The lose of dorsiflexion on one side is more significant. The prosthetic binds the area behind the knee causing you to need to bring that knee higher and thus can over extend the opposite leg. I have reduced my crank length to 165mm. I have learned to cycle at higher cadence 90 to 110 and use low cadence 50-60 to build strength. I would love to improve my efficiency even more.

Adding pedal upstroke power is key.

Optimal cadence depends on duration of the effort. Sprint 130, 5min 70, 20 min 80, 2 hrs 90 so its a U shape. Max power needs high cadence due to strength limit, vo2mx needs low cadence due to cardiac limit , long duration high cadence again due to muscle fatigue. Science sometimes is just unnecessarily dumb in complicating things. Edit: Thanks for feedback guys. Just keep in mind the numbers are rough averages to illustrate. Your individual optimum may be bit higher or lower depending on your training history, but you get the idea. When it feels right it probably is.

I ride a fixed gear commuting bike year round with a low gear(38/16) in an area that is mostly flat bur some short climbs. What I find is you can learn to pedal efficiently at various speed/cadence and load/effort. Going downhill or with a tail wind to keep pedalling smooth, under control. And then uphill or into the wind smooth application of power at lower cadence. To be smooth at 60, 80, 100 and 120+ cadence. There is a short sequence of rolling hills on the edge of the city. Speed is 10 to 15km/h at the tops and 40 to 50km/h at the bottom. My fastest segment time is still on a fixed vs a geared bike. I am 185cm tall and ride with 175mm cranks on all my bikes. I have found with shorter cranks on road it does not feel like I am using the entire range of leg muscles. But on track I ride 170 cranks with a 46/16 and it feels OK, mostly riding 28 to 35km/h. Looking forward to part 2.

The problem is that first you need: 1. Ideal crank length for your body and discipline/position(road, tt, gravel, xc..) 2. Perfect q factor/stance width 4. Perfect cleat position, shoes and insoles. 3. Perfect symmetry L/R. Shims/wedges, different crank length L/R- nobody have perfect symmerty by default! One you get all this correct than you can start..

Hi Guys, this is very interesting. I've been riding for nearly 60 years so i have some bad habits. I've tried making my strokes "back and forth" like you appear to be saying, 11 o'clock to 1 o'clock and 5 to 7 but its never felt right. Recently I've been pulling the upstroke, thats the areas 5 and 6 in your first slide by concentrating on lifting the rear leg only and letting the front leg do its own thing and my trainning loop times have tumbled, I'm going about 10% faster. My reasonning is that instead of the negative torque (the red bit on your torque graph) I'm now producing positive torque there (turn red to blue). By practice over about a month I can easily keep this up for more than 30 minutes. I am now trying 0.5kg ankle weights and feel as though those muscles are getting stronger (I'm even faster when I leave them off). Am I doing wrong? Is my back and forth techniqe simply needing more exercise and give up on the lifting up or even can I combine both? Any views?

Shorter cranks seem to follow this logic.

Great presentation! My question is if my indoor bike on a smart trainer has 172.5 cranks and my outdoor bike has 170, is this a bad thing or a long term issue. I typically ride out on weekends and 3 rides during the workweek.

A lot of this seems to depend on saddle height

Can you address crank length inyou need podcast?

In studying physics and physics in sports, we sometimes get terms confused. In terms of Power, I think we need to are talk about 'Work' ; W=F x Distance. This is the same for the length of the push by a speed skater on ice or the force on the pedal by a cyclist. Time of application is important. The same force applied over a longer period = more 'Work' being done and faster speed. ( im only referring to the time of application to the pedal, not the distance the body part travels)

Learn to ride the rollers, fixed, free wheel, two legs, one leg. It'll be very obvious when / where you aren't smooth.

Painful to listen to… First there is the difference between feeling and measuring. I built an adjustable bike that is plate loaded (it lifts plates instead of turning a wheel) to isolate forces produced - that’s my static measurement. What a rider feels is feedback from muscles. A tiny muscle working at its limit will feed back the same information as a large muscle working at its limit, but produce almost no force. That’s why people think they are generating force by pulling up on the pedal. Trying to teach a rider to pedal better by feel can’t work. Try engineering a pedal stroke based on the geometry of the body and its large muscle groups - glutes & quads. Quads extend the pedal from the knee, which is only effective from 11:00 to 2:00 (you actually got that one right). With the range isolated you then have to look at mechanical advantage. The attachment point of the connective tissue from the quad is very close to the pivot, it’s designed for foot speed in running. If you teach a rider to isolate just the quad by having them clip in with just one foot and accelerate the pedal from 11 to 2 over and over until that range becomes second nature, you can then start testing for effective cadence. Quads don’t like to produce torque, much below 80 RPM and the heart rate goes up without a corresponding change in power. Using hamstrings to pull back on the opposing range doesn’t work. Try getting the hamstring to keep up at 80 cycles/second - not gonna happen. Teaching a rider to isolate their glutes is easy, but It goes against their primary skill set - lifting their body weight. The basis for walking/running/standing is lifting your body weight. It involves firing the quad and extending from the knee. It’s your most used skill. When you sit on a bike and think about pushing down with the pedal at 3:00, your brain says “we know how to do that” and it fires the quad. From that position, extending the lower leg from the knee pushes the pedal forward. I have a simple way to teach isolating glutes, it’s called sitting. When you sit on a chair with your feet on the ground and lean forward, weight transfer is to the floor via the glutes. My point in all of this is that you’re not critical enough about how riders are pedaling, you lack a means of measuring, and you haven’t really figured out the engineering.

Great show and presentation. Does crank arm length affect how smooth is one's pedal stroke? I'm 5foot 3, not tall, fairly flexible and don't have any major hip impingement. I have been using 170mm cranks for the last 3years but just started trying out 165mm cranks. Still getting used to the shorter crank arm and i do feel my pedal stroke is smoother but feel it's more effort when using bigger chainrings. I missed the leverage from 170mm crank arms? Is this just a matter of giving my body time to adapt to the shorter crank arm ?

Why does the diagram at 28:05 show peak torque being at 3 o'clock? That's about where I start applying power and I peak at just before 6 o'clock. Seems counterintuitive.

That guy says you know way too much!

Rollers. It’s almost impossible to ride them without a smooth cadence as described in this video.

Eliminate P-minus and gain free power. IMO

The first and most important optimization is the body. This accounts for at least 90% of the performance. And you can't buy that with money. Getting your body into good shape is hard work over many years. And you learn everything about how to pedal and sit correctly through experience. Everything else is nonsense.

Id be a bit more impressed id they could spell the word "pedal" correctly.