Monday, March 11, 2013

Dorsiflex or Not?

The pretension concept of the ankle upon jumping is an interesting one. Pretension caused by ankle dorsiflexion during air time, is something that I (try to) teach for certain multiple double-leg jumps. But, is it the optimal way to perform a repeated jump? In coaching different athletes, I find that it doesn't seem to be very natural.

To determine the effectiveness of this technique vs. another strategy would require accurate measure to assess the impulse of the jump(s); something difficult to measure without the right technology. I think you can get a good visual idea of it, but obviously this is subjective.

The pretension theory makes sense in working to develop and increase foot/ankle stiffness and elasticity, especially as it relates to sprinting, just prior to the support phase, where this foot/ankle position is commonly found (although this is questionable for some sprinters). The idea with the pretension, I presume, is minimal ground contact time with maximal rate of force development. Simon Hunt's video below is nice demonstration of the ankle position and the reactivity of the rebound in these types of depth jumps.


The excerpt below is from Jim Radcliffe and Robert Farentinos's "High Powered Plyometrics". In this case the 'pogo' would be a learning exercise for the jumps, and the specific technique involves the pretension position: "upon takeoff, the ankle must lock the foot into toes-up position (dorsiflexion), maintaining this locked position throughout to ensure sturdy contacts and quick, elastic takeoffs."

Again, in my experience, dorsiflexing the ankles (pretension) after takeoff does not seem to be a natural method of preparation for the subsequent landing or repeated jump... I am thinking of a tip rebound in basketball or a repeated jump in volleyball. Is the toes-up/dorsiflexion position the most optimal one? Of course, the goal is not to land on the toes, but is it necessary to unnaturally pull the toes up after takeoff? Or is it just the easiest way for us coaches to explain, teach, and get the right effect - elastic conversion of kinetic energy?

The Maasai people of Kenya and part of Tanzania, are well-known for the adumu, a dance ritual of repeated jumps, attempting to jump as high as possible. I would be very interested in what sorts of impulses they create and heights of jumps they can attain. To me they seem to get pretty good heights with good elastic rebounds... without the same dorsiflexed position as taught in some plyometrics.


So does this mean that the dorsiflexed position is flawed, or could the Massai be more reactive if they adopted a more dorsiflexed ankle upon jumping? Or, do the Maasai possess better innate capabilities to modulate stiffness at the appropriate times? 


In my experience, certain athletes have this natural elasticity, and others are like flat basketballs and takes a great deal of work. Pretension is an interesting concept, and it's utilization in training should help make for better training, however, it's relation to ankle dorsiflexion is one I am curious to investigate further. 

AS

6 comments:

James Marshall said...

I do coach it like Radcliffe's pgo jumps. Bosch also emphasises it on his running drills.

Brett said...

Interesting article. I have wondered this myself at times. Out of curiosity, outside of the dorsiflexed position feeling unnatural during repeated contacts, what do you think are some other potential negative outcomes or limitations? Lately I have been curious as to whether teaching such aggressive dorsiflexion through movements such as wall-drills, bounding, continuous jumps etc. could predispose certain athletes to issues such as Achilles tendonitis, even if their foot contacts are controlled simply because of it being something people tend not to do naturally at high volumes or intensities. Interested in your thoughts....

Matt Gardner said...

I'm more toward the Radcliffe end. I teach pretension as there aren't many plyos you can do that way and get away with it except tuck jumps etc.. (and the ground contacts in the toe pointed setup are too long anyway for most with that method). Tuck jumps etc.. ground contacts, I see some folks that even with good dorsiflexion during the air cycle will show best elastactity and performance in a slightly higher ball of foot position than the normal and some folks that can go more flat. Reality is there are slight differences in ankle anatomy and ranges mechanically where people will be able to display the best stiffness (part of this is sport and activity adaptations as well). I'm not talking about people with toe drop just because the heights are too high and the body decides to give it more range to decelerate. I think and research supports that Rate of loading and stretch matters as does the actual angle you load. With more midfoot to forefoot and neutral contacts in vertical plyos you'll get more carryover to stiffness at the ankle in those joint ranges. These are joint ranges in good sprinting, change of direction, multiple jumps with bigger angulations (tuck, star, etc..), single leg hops especially translationally, bounding, skips for height, distance etc.. Most are training for locomotion, change of direction, and to do more training so pedagogically it makes sense to me to teach pretension.

Aaron Schwenzfeier said...

Thanks for the comments fellas!

Aaron Schwenzfeier said...

Brett,

I am not sure of the negative, other than maybe the cost of time to get this consistent pattern... ???

I do certainly think those exercises expose the Achilles, which I think (like any other tissue) would need time and progressive volumes to adapt. I do believe there are such subtleties with biomechanics that each athlete and their tissues will respond ever so slightly different, making it difficult to know.

The trick, obviously, is the optimal type and amount of use (that's an easy one! ha!), which I think tendons might be harder to 'read' than muscles??? Tendons are weird, in that certain circumstances do better with 'painful' eccentric loads for healing... and if it gets to the point of tendinopathy, then things get really whacked: neovascularization, sprouting of free nerve endings, and the different connective tissue "healing"...

More thoughts?

Aaron Schwenzfeier said...

Matt,

Good points. I think I probably see more problems with this problem because many athletes I work with are outside of track and field, so some do not have that lower leg responsiveness (or any idea how to create it), and different postural adaptations throughout their lives.

Personally, I can perform the plyos in training fine, but to 'toe-up' going for multiple jumps while fighting for a rebound in basketball, is downright awkward. Yet, I know of many of our basketball guys that have the elasticity we would like to see in those jumps, without the dorsiflexion.

So maybe my question is, is it the 'toe-up' we are after, or the elastic response? Can you have the the elastic response without the toe-up?

I pretty much agree with everything you said, just trying to get a clearer picture of something that seems so unnatural, even for those with the natural 'bounces'.