Friday, August 17, 2012

rethinking the run cycle

While I was looking into options for running again (post hip-arthoscopy), I've started reading a lot about "pose" and "chi" aka, "minimalist" running techniques; essentially landing on the midfoot and keeping a slight bend in the knees as way of lessening impact while running (and preventing more injury)

As I looked into it more, I started approaching it all with an animator's eye. One of the things I love the most about animating is researching motion - finding the right movement style for the character, or sometimes just learning how to see deeper into specific types of motion.

I'm always used to approaching a run like this:

But looking at real life as way to inform your animations:  (Examples below (taken from )

This shows the standard footwork in most animated run cycles. I'll go back and some point and diagram these out a bit, but it has a lot of commonalities with what you see in most animated runs...knee goes straight for a couple of frames before contacting with the heel. Back foot peels away. Often a bit of chest compression after the impact.

Now let's check out the midfoot running style.

And here is the midfoot strike in action (on some of them - the last guy is a heel striker and you can see the impact shock as he lands, which is often a great touch in an animation). It looks more effortless, but the difference here is fairly subtle. Rather than stomping down on the heel, they pull the foot back further to land on the ball of the foot.

As an animator, the "pose" running system caught my eye, as it works on the tenet that the run is based off of a single 'correct' pose, something I've always ascribed to. The before/after is pretty clear in this section.
The main differences-
  • back foot kicks up to the backside rather than extends out (pulling into the 'pose')
  • much shorter foot stride. Plant is under the body.
  • 180-200 strides per min.
  • body leans forwards and uses the continuous falling motion to propel you forward, while the up down pumping action keeps momentum.
  • never touch the heel to the ground.
  • less up and down motion in the body
Another how to by the pose running guru.

So what does this mean for animators?  More options to consider how a character might run while injecting plausible motion. Maybe the heelstrike is more appealing, as you can get a slower stride length that might fit your character proportions better. Or perhaps on a short legged character, the running on the balls of the feet with more of a pumping action would make more sense.

Let's look at another extreme

What's interesting after looking at this is seeing how much closer the pose running system is to sprinting.  Especially with the high kicks.

I found I was lacking clarity in forefoot vs midfoot running, so dove back into google. 
From Newton Running...product placement aside...good examples of forefoot endurance running v. sprinting.

AND MORE (Barefoot Running site with slow motion clips)

This barefoot running site has what every animator wants to see...curves! They measure impact force as they run.

Good example of the forefoot strike with and without shoes.

This last bit is interesting, as it factors in how a shoe can influence gait and foot plant. I'm now curious to see people running in boots or with thick soles and how that influences stride length.


Ryan Griffin said...

Thanks Coop! This is great info to have while I work on my animation skills.

Cassie said...

Shoes are all different, but if the heel is thicker than a normal sole the foot cannot bend as much as it wants to as the movement is restricted, the foot goes through a curve if you have noticed the heel and ankle leaves the ground first supported by the ball of the foot and then the toes in a rolling motion.

The common problem with shoes is they can constrict the normal motion that is produced when walking or running while in bare feet (although if people are not used to walking or running in bare feet it can cause the arches of the foot to collapse or cause damage to the ankle since the muscles and tendons around the ankle might not be developed enough to support the ankle by themselves.)

It is by not bending in the same place that is not comfortable as it will not be at where the bones of the feet allow the foot to bend and can cause the walk to be shorter or longer as case maybe.

The shoes also can pinch the toes which since the toes spread out to support the foot and the last little bit of weight from the body before it leaves the ground can be not that good for balance.

On a note of shoes, women's high heels (especially if they are quite high) tip their body of balance, the centre of gravity is flung forward of the normal posture resulting in that gait.

Nice post by the way :).

Virgil said...

great stuff, thanks for sharing!

Studio Fael said...

Thank you for sharing. This research could easily serve as a model for research before animating anything.