Tadej’s short-ass cranks

Triathlon Forum
21

Think so (on the road bike after the switch).

Recently listened to the Escape Collective podcast with Nick from Wove. Pogacar has adopted this progressive fit that Nick and others are advocating, other than increasing crank arm length. The move to 165s is an anomaly to this though.

a common red flag in any discussion of a topic is when only positives are communicated with no examination of the tradeoffs - this goes for crank length too.

Yes, 165’s feel great on the hips, zero doubt about that. But when we shorten the distance from where we sit on the saddle to where our foot is in contact with the pedal in its forward and horizontal position, we shift our muscle recruit to be more quad dominant.

So, if we leave our saddle where it is and shorten our crank length, we increase quad usage. If we move the saddle forward without changing crank length, we’ve increased quad use. If we move the saddle forward and lengthen the crank length, we help maintain the muscle usage we experienced in our prior position. If we leave the saddle where it is and only lengthen the cranks, we increase glut usage by close off the hip angle.

When Ronan interviewed former World Tour pro and gravel privateer, Nathan Haas, on his Performance Process podcast, Nathan spoke about this, but attributed the shift to quad use to the change in effective sta without recognizing the role of crank length in that equation.

What I see often with top bike fitters is that they’ll put someone on short cranks to open their hips, and then the fitter will move the pro athlete rearward of the bb to keep the rider’s glutes engaged - that recloses the hips off, canceling out the effect of the shorter cranks and reduces the rider’s ability to apply force onto the pedal perpendicular to the crank in its forward and horizontal position.

If a rider scoots forward and raises their front end, they have drastically opened up their hip angle and lengthening the crank to keep the glutes engaged will close off the hips some, but in my work, the hip angle remains more open than it had been prior to scooting forward and raising the front end up, so the rider on 172.5mm or 175 cranks still has a more open hip angle in the end, and they’re keeping a larger muscle group engaged, and our time to fatigue is longer in duration when we use larger muscle groups vs smaller muscle groups, which is the very sound point Nathan Haas makes here. (he just didn’t take into account the role of crank length in that argument)

I write more about this topic in this blog post. https://wovebike.com/blog/bikefit

It would be interesting to see Pogacar leave his bike set up the same but change his crank length between 155 and 172.5 and test his time to 4-5 mm/l of lactate.

22

You didnt mention the one thing we all do as triathletes when shortening cranks, move the saddle up?? Is there something different with the road position that you dont do that??

And the other thing when going forward more, it was always understood that from a typical roadie position, you now use the hamstrings much more. Is that not the case moving a roadie position more forward?? And it is a thing, just ask any roadie that never trains forward and then doing a tt in that position, smashes the hamstrings…

23

You didnt mention the one thing we all do as triathletes when shortening cranks, move the saddle up?? Is there something different with the road position that you dont do that??

And the other thing when going forward more, it was always understood that from a typical roadie position, you now use the hamstrings much more. Is that not the case moving a roadie position more forward?? And it is a thing, just ask any roadie that never trains forward and then doing a tt in that position, smashes the hamstrings…

definitely move the saddle up when changing crank length due to the the pedal being higher when the crank is in the 6 o’ clock position. and yes, saddle height is a fourth factor in hip angle, for sure.

there’s a lot of research showing that efficient cyclist apply force between the 1 and 4 o’ clock position of the pedal stroke and because of interlimb coordination, they’re primarily using the glutes and quads and can’t simultaneously also heavily recruit the hamstrings.

The issue with the hamstring going to a TT/tri position is something I’ve definitely experienced in the past and I’m sure we’ve all experienced, but it’s much more to do with flexibility, and a poor fit in general. For example, I don’t think too many roadies would struggle to get into Magnus’s, Sam’s, or Trevor’s tri bike positions, whereas many people would struggle to get into AB’s current position on his tri bike, and probably have hamstring tightness.

24

There are many degrees of freedom in this situation. I dispite that a few mm different crank length significantly changes muscle recruitment. It’s the same basic movement pattern. Your body is just not that sensitive. It’s true that many cyclists do not engage the glute as effectively as they could, but this is more a neuromuscular deficiency and is trainable from work off the bike to improve your movement patterns.

Also, the hamstring is a very misunderstood muscle. If I’m interpreting your post right, we agree on this I think. There’s no physical way to recruit your hamstring during the power phase of a pedal stroke. It contracts while bending the knee, not extending it. Any issue with the hamstring in a tt position is due to issues with the glutes/low back putting excessive tension in your posterior chain, not because of a misutilization of the hamstrings.

25

There are many degrees of freedom in this situation. I dispite that a few mm different crank length significantly changes muscle recruitment. It’s the same basic movement pattern. Your body is just not that sensitive. It’s true that many cyclists do not engage the glute as effectively as they could, but this is more a neuromuscular deficiency and is trainable from work off the bike to improve your movement patterns.

Also, the hamstring is a very misunderstood muscle. If I’m interpreting your post right, we agree on this I think. There’s no physical way to recruit your hamstring during the power phase of a pedal stroke. It contracts while bending the knee, not extending it. Any issue with the hamstring in a tt position is due to issues with the glutes/low back putting excessive tension in your posterior chain, not because of a misutilization of the hamstrings.

Agreed on both points.

And if I have an athletes super sensitive to crank length, I see that as a sign of something else not being addressed (too low of sodium per hour, stuff to work on with a physio). But, 7.5mm (165 to 172.5) is a whole lot and I do see a change in athletes reporting much less quad fatigue. And, perception aside, if they’re perceiving a change with a 7.5mm change, we can’t discard the idea that there’d similarly be an effect with a 2.5mm change, albeit smaller, and that should be assessed in a lab (lactate, time to fatigue, smo2 sensors on differing muscle groups).

Hamstring: look up interlimb coordination

26

Recorded a new podcast over at Escape Collective on crank length, recently: Performance Process: Why shorter cranks aren't for everyone - Escape Collective

discussion: Discord

1 Like
27

@Nick_wovebike have you considered the option to instead of only moving seat rearward in response to shortened cranks, to effectively move the foot forward slightly by moving the cleat back towards mid foot? This is the route I took with my short cranks on both my Tri bike and Road bike, and I am comfortable and fast now despite hip limitations and past Achilles/calves running injuries. I use the Patro Mid foot cleat adapters on my tri shoes, and back of stock position on my road shoes.

28

So yes, this can be a clever way to provide clearance at the top of the pedal stroke while still increasing the distance from the ball of the foot to where you are sitting on the saddle to keep the glutes engaged.

The problem with this, and the reason you will not see much if any top pros using this approach, is that the more midfoot you go, the more you remove your lower leg from the power production of the pedal stroke. In the mid 2000’s, that was all the rage, but we quickly found that our biomechanics benefited from ankle flexion that is available when the pedal spindle no more than 2mm behind the first metatarsal, and we saw benefits in knee and hip tracking with the lower leg is more involved - the more we remove the alignment correcting effects of the ankle, the more we can feel misalignments in our knees and hips. And while it seems appealing to transfer power through the skeletal system and not recruit the gastroc and soleus, their recruitment is helpful in terms of power production.

3 Likes