How Important is dorsiflexion?

How Important is dorsiflexion?(if stupid question please just answer the second one.)

How much is enough?

I made a similar thread a year back but it was way overthought,all over the place and got no response.

it is very important with respect to power application to the track. a foot that is not dorsiflexed will collapse when hitting the ground and enrgy is lost, and it takes more time. if the foot is dorsiflexed then all the force is applied to the track.
people tend to think the whole cycle you should be dorsiflexing but at push off you naturally are not and should not dorsiflex.

as far as too much, all i can say is if you are forcing to keep your toe cocked, like straining, then that is too much.

Hill sprints help the runner dorsiflex naturally, then when you transition to flat speed, your muscles are used to that position.

Sorry If I was a bit unclear, I half of my point was about the ability to have good dorsiflexion. As in being mobile enough to have enough dorsiflexion(and how much is enough as in angle.).

Here is poster jmf communicating what I’m getting at more efficiently.

"Coming down from the 800m to the 400m I’m trying to learn how to really sprint. One thing I’m wondering is if inflexibility around the ankle - as in I can’t squat low without a heap of plates under my heels- is a barrier to running fast. If so, which stretch/exercise would best fix this? "

your squating issue is a hip flexibility problem. once you squat more you will gain more flexibility in that area

How do you know? I’ve had a professional address limited ankle mobility, only his solutions didn’t work. I know I have it that’s for sure.

Sometimes it’s soleus tightnes and sometimes it’s structural. If the ligaments in the back of the ankle are short (posterior talofibular, for example), that can prevent the talus from dropping as dorsiflexion starts causing a jamming or bony “stop” in the top front of the ankle.

Thanks. Do you think this will hurt my running?
Surgery, is it an option(if the problem was indeed structural)?

Unless dorsiflexion pinches the front of your ankle and hurts during running, I wouldn’t worry about it. I would highly doubt surgery is necessary. You can stretch ligaments if that’s the limiting factor in all of this.