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Energy Expenditure and Weight v. Shock Suppression

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Chris Gracey, Oct 31, 2011.

  1. Chris Gracey

    Chris Gracey Active Member


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    Hello Folks!
    I suppose I can't lurk forever...

    I need some guidance. I have a client who is an american football player for a professional team. He wears an OTC orthotic issued by his team physician that is mass produced and minimally customized by his training staff to help treat a mild pes anserine bursitis. I have created for him a simple insert that suppresses shock through the use of kevlar and increased surface area contact. The device also combines the unique properties of slow recovery poron (SRP) and strategically placed closed and open cell foams to enhance "feel" and further drop GRF. While the subjective response to the change in neural sensation is quite positive, I am concerned with the additional 2-3oz of mass and his energy expenditure over the course of a game.
    Owing to the fact that the additional mass will require greater effort, does anyone have a copy of:

    An equation for prediction of energy expenditure of walking and running
    J Appl Physiol May 1, 1973 34:(5) 559-563

    or other articles you would recommend I read?

    AND Does anyone have thoughts or ideas from personal experience in field sports that I could learn from?
    What works best in a cleat for a given pathology or what modifications lead to a more comfortable foot environment?
    Do things like turf friction play a larger role? In-shoe friction?
    So long as he's comfortable, should I be less concerned all together and hope that training effect makes up the fatigue difference?

    Thank you. VR. Chris
     
  2. Chris , I'm sure that the extra weight will have some effect but a few training sessions and that should not be an issue.

    Also being a power stop start sport less of an issue than an endurance sport.

    I'm sure some extra HGH human growth hormone should do the trick.;):bang:

    No blood testing for PEDS is a disgrace - I digress.

    But yes if the player is liking the device and pain is reduced rest easy.
     
  3. I pretty much agree with Mike. I sat in Philadelphia airport last night watching the game between Dallas Cowboys and Phili. Now, I'm no expert on American football, but from what I can see the mass of the orthotic is not going to be a major issue in a sport in which the competitors wear many pounds of body armour and only actually stay on the pitch for about five minutes at a time and, moreover, only actually "play" for about 15 seconds at a time during that five minutes. Indeed, any added energy expenditure resulting from the orthosis, could easily be negated by the player not getting involved in the completely over the top "congratulations" the players seem duty bound to reward upon each other, just because an adult, professional athlete, managed to catch a ball and run into touch with it. Yeah, well done. Man up and take the tackle at least.

    My Mrs asked me if I understood the rules of the game, my response was something along the lines of: "It's a bit like rugby league only less intense".

    P.S. In fact one of the players who comes onto the pitch just to punt the ball (and then goes off again) appeared to be wearing an AFO, because his ankle was ruined from (and I'm guessing) repeatedly punting balls and doing nothing else. Priceless- "what position do you play?" Well, I come onto the pitch catch the ball and kick it then I go off again. Even that is not the easiest job on the pitch. The guy who takes the conversions has got it even easier- he has a player catch the ball for him, tee it up, hold it for him while he takes the kick from right in front of the posts-regardless of where the touchdown was scored. Perhaps the guy who catches the ball and tees it up only actually comes on to the pitch to do this job too?
     
  4. Chris Gracey

    Chris Gracey Active Member

    Thank you Mike and Simon! I will take the "Be less concerned" approach which is pretty much my favorite way of dealing with all things in life anyway. Simon, you watched my client have a pretty great night last night. I was an 8-man at the University of Arkansas and you're description of American football is spot on!

    Peace and Props,

    Chris
     
  5. I didn't see the end; who won?
     
  6. Chris Gracey

    Chris Gracey Active Member

    Eagles! 34-7 :D
     
  7. Chris Gracey

    Chris Gracey Active Member

    The Cowboy's kicker had something wrong with him but in all likelihood, it was an inebriated slip and fall accident at a pub that injured him or something mundane and non-sport related. The TV crew reported it as a case of "Drop Foot" as if that could appear as a primary diagnosis. What he does have is a cushy, high paying job that's in jeopardy if he doesn't heal quick or find a better AFO. The holder for a kick is the most fun job of all! The center snaps the ball to you, you have to catch it, put it on the ground, angle it based on wind direction and angle of foot attack and then spin the laces away from the kicker's foot all before the kicker kicks it. It takes timing and skill so this is often done by the quarterback. The kicker? Definitely the easiest. Heck, I can make a 35 yard field goal. It's a stretch to call it a "Skill" position.
     
  8. How often does the kicker miss such "field goals"? I played blindside flanker (not renowned for kicking skills), but I reckon even I could hit > 95% when the ball is positioned smack bang in the middle of the posts. And these guys earn? My Mrs could probably hit 70%+
     
  9. efuller

    efuller MVP

    Depending where you put the cushioning material, I would worry more about the energy sapping effect of running in sand. Too much energy absorbing material could decrease performance in a push off by the foot having to deform the energy absorbing material before they can solidly push off of the ground. The effect could also be very small and it would depend on how it's constructed.

    Eric
     
  10. Chris Gracey

    Chris Gracey Active Member

    There in lies the art.;)

    For example, relieving a dropped met-head on a runner, given this technique, requires a certain thickness of SRP be used in strategic areas. In order to exact a change, there must be enough material to make a difference. But too much will bring about an un-desired result. Great Point, Eric!
    Unless the material in question could be pre-loaded during initial acceleration to a point in time the runner achieves enough momentum to overcome the effects of the slight deceleration moment experienced inside the shoe.

    My method for pre-loading the material adds a few oz's to the shoe so that's why I'm inquiring about energy expenditure. But I think I'm convinced by previous posts (and the fact that my client had 2 TD's and over 250 all purpose yards this past Sunday) that for the position he plays in this sport, the importance of being comfortable during the game trumps lightness in the shoe and that will positively effect his performance far more than any additional fatigue experienced by the end of the game.


    Guys,
    Does anybody have a method for getting free journal articles online? I'm not currently affiliated with an institution and prefer to draw my own conclusions from the studies I read. THX!

    Chris
     
  11. Chris:

    In patients wearing cleated shoes, I will often choose the thinnest and lightest weight orthosis that will do the job since added mass will affect running performance, but only slightly in sprinting sports such as American Football. As far as energy expenditure with masses added to the shoe, here are my PowerPoint slides on the subject from my lecture: "Barefoot vs Shod Running: Which is Best?"

    Hope this helps.
     
  12. Chris Gracey

    Chris Gracey Active Member

    So much to absorb!
    I can't thank you enough for your generosity,
    But one day i will!!
    :drinks

    Peace and Props,

    Chris
     
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