Quik, I have Superfly G5’s and they are extremely stiff as you know, around the big toe and pretty much everywhere. I loved how they got me ‘up’ on the balls of my feet effortlessly. But my achilles tendonitis got ridiculous, I switched to the extremely flexible Zoom Maxcats and the problem is going away finally [with no loss in speed which surprised me].
Stay away from anything with a stiff plate.
Stand up on one leg. Go up on to the ball of your foot. Flex big toe down to grip floor, whilst ball of foot is also still on floor. You might lose your balance and your heel will more than likely sink to the ground. Now stand on ball of foot again but this time curl big toe upwards. You will not likely lose your balance and your heel will likely stay up, several inches of the ground.
So Charlie is saying that there is dorsi flexion of the foot as swing foot passes support leg, but just before ground contact, the swing foot starts to plantar flex very slightly, ball of foot landing on ground but with big toe curled upwards (for balance/better function).
QUESTION FOR CHARLIE…
Come to think of it, as the foot moves into the triple extension angle, is it appropriate for the big toe to NOW flex down as a means of natural pushing or not?
A better test than the one in my last post is this. Do some simple double leg vertical hops. First 10 easy reps do with toe curled up as you’re about to land/landing. 2nd 10 reps with toes curled down as you land. You will soon realize why toes curled up is better.
I remember my 1995 Level II school at BYU where Loren Seagrave, Andy Roberts, and Craig Poole demonstrated the devices designed to pull your foot into dorsiflexion. Not sure if this was there debut.
Charlie,
When you first work with an athlete, how do you address this? If they’re not doing it, how do you go about “teaching” them to? If they’re at a certain level, do you not even bother to check?
I tell them to toe up when the foot passes the support knee. If they have reasonable flexibility, it’s usually pretty easy. I certainly don’t tie their foot to their shin!
LMAO…
When talkin about dorsi flexion. If an athlete has a problem with pointing their toe up at touch down, would this be a strength issue or technique issue. Well obviously it’s a technique issue, but can it or should it be fixed by adjusting technique somewhere else. Or will it fix its self once that athlete is strong enough in that area. Dwight Thomas is a world class sprinter and he still does this. How much faster could he be…
Also…What affects do you all think that a rigid spike plate would have on acceleration when compared to the ones with just the forefoot plate? It seems like the rigid plate would be benificial when it comes to acceleration. All of the spikes i’ve ever owned have had a full length spike plate. But this past summer I switched to one with just the forefoot spike plate. They feel more natural, but acclerating feels different. Not neccessarily better or worse. But just different. Maybe i’m just feeling the added flexibilty.
[QUOTE=Charlie Francis]I tell them to toe up when the foot passes the support knee.
Charlie, is it fair to say that you work first to enhance or at least ensure that an athletes plantar flexor static strength is balanced so that upon landing, the heel does not collapse, thus ensuring proper transfer?
Is it too late to revive this thread? I’ve been looking for all the variations of dorsi-flex theory as propagated by sprint coaches, some of which advocate cocking the foot all the way through the recovery (immediately after toe-off), and I’ve finally ended up at this site with what doesn’t really look like dorsi-flexion at all. As far as I can see, it involves not the whole foot but just the toes, which are cocked upwards in order to ensure landing on the ball of the foot.
What I would say about it is that, unless the sprinter has a ballet dancer’s ankle-flexibility, a completely passive foot is unlikely to land toes first. But even if it does, what we are really talking about is landing on or near the front rim of the running shoe. That would be no disaster, since the force experienced would be very slight and short-lived. At the moment of contact, it would roll down onto the ball of the foot, and progress from there to the flat-down position as the foot passes under the c.g. It wouldn’t interfere in any way with the smooth transition to the drive phase.
In my own sprinting, I cultivate complete passivity in the recovery foot, from toe-off to toe-down, letting it find its own angles as the leg throws it about. But as a result of doing flexibility work on the ankles, my foot does tend to hang at a steeper angle than most people’s. But in practice all this means is that my footsteps tend to be quieter than they used to be. I do land forward of where the main pressure point should be (the ball of the foot), but the slight preliminary pressure exerted by the toes means that the ball doesn’t hit the track with the same slapping sound as previously. You could say that the toes act as an initial shock-absorber for the foot, giving a more cushioned impact.
The kind of dorsi-flexion I have heard talked about here is not something I would want to do, but it is the one I would have the least criticisms of. It does at least have a certain logic. On other sites all I can find is Mickey Mouse physics, with such nonsense as “bring the foot down directly under the centre of gravity”. I challenged two of those experts to show me a photograph of a sprinter doing that particular trick. Needless to say, neither of them could meet the request.
I think you’ve got the right idea letting the foot be passive during the leg recovery phase of the stride. It’s my understanding that you want the leg to recover as quickly as possible by relaxing it and stepping over the opposite knee which will flex the leg and reduce the moment of inertia, causing it to recover quicker. Prior to the foot plant you would dorsi-flex to minimize braking forces. As for plantar flexing on toe-off…I don’t know: CF’s literature reports the hip contribution to be much greater than the ankle, and frankly I don’t think I can make the plantar contraction before the foot has already left the ground again. Maybe specific work of hills, med ball throws, and cleans will cause the ankle to plantar flex on toe-off automatically.
I don’t think dorsi-flexing or not dorsi-flexing makes any difference to the braking forces. Draw a straight line between the ball of the foot and the body’s c.g - a line that points upwards and slightly backwards (meaning a slight deceleration) . That’s the direction that the resultant force between foot and track has to point if there is to be no rotation. (And balance must take priority over all other considerations.)
This shows that the size of the braking force is determined purely by the distance that the foot lands in front of the body’s c.g. There is no way of reducing the braking force (as coaches are always urging us to do) except by bringing down the foot closer to the c.g. However, there is a price to be paid for that. The build-up of forces of the leg’s various muscle groups prior to the drive phase is something that takes a measurable time to achieve. By landing in front of the c.g., you accept a slight deceleration as the price paid for having the time to load up the muscles with tension, in preparation for the recoil behind the body. By reducing the distance between foot and c.g, you effectively reduce the size of the recoil. It might still be a good bargain, or it might not. No one can know the right trade-off except the sprinter himself - which is one reason I believe that self-coaching is the superior coaching. Your internal sensors are always more reliable than the coach’s eye judgement.
As for plantar flexing on toe-off…I don’t know: CF’s literature reports the hip contribution to be much greater than the ankle, and frankly I don’t think I can make the plantar contraction before the foot has already left the ground again.
There is no doubt that the hip flexors/extenders are the main driver in sprinting. The straightening of the leg and the raising of the heel are subsidiary forces. But I don’t understand your difficulty with plantar-flexing. This takes place between the time the foot passes beneath the c.g. and toe-off. It’s just a matter of raising the heel, and is done simultaneously with the straightening of the leg.
If you look closely at slowed-up videos of top sprinters in action, you will see that there is plenty of time to do that. I remember looking at clips of Linford Christie, and noticing that he even had time to briefly pause or even reverse the plantar-flexion - something that isn’t in theory desirable, but it is sometimes made necessary by the overriding need to point all forces through the c.g. So sometimes the action looks a bit jerky and twitchy.
I gather from a few sources (including Yessis) that plantar flexion as the foot leaves the ground allows that leg to be slightly bent at the knee (amongst other things).
This is supposed to prevent excessive vertical force being produced (i.e. the action becomes a leaping or bounding action). Reciprocal inhibition may also play a role - a straight leg maintained through posterior muscle activity could inhibit firing of the hip flexors. Also the range of extension of the leg behind the body can partly be the result of forward hip rotation which could again inhibit contraction of the hip flexors.
According to Zatsiorsky, the hip flexors are supposed to be active mostly early in the recovery of the leg as the foot leaves the ground. So anything that inhibits the correct timing of the contraction of the hip flexors will most likely decrease running performance. I’m not sure if the adductors are inhibited in a similar fashion, but they are also heavily involved in the initial forward leg drive… so I could be talking out of my arse… :eek:
I’ve created a thread here so people can post back information about the flexability of thier spikes:
http://www.charliefrancis.com/community/showthread.php?p=147110