Acceleration phase

Posted In: The Classics

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    x-king on #8532

    I have a good drive phase, and once I lift my head up at about 20-25m, I lose all momentum and power that I have generated through my drive phase and then when I get back into my stride I start to make up the ground that I have lost from around 30-50m.

    You guy’s are the experts on this kind of stuff,
    What can I do to improve, and if possible, stop what I am doing wrong???

    Thankyou very much

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    jjh999 on #21671

    Allow the torso to raise the head.

    If you are accelerating properly (each stride progressively increasing in length and speed; direction of force changing from horizontal to vertical), your torso should raise naturally as you move throught the accleration phase (as my contemporaries on here know how much I hate the term 'drive phase'…;)). If you are consciously raising your head, you will consequently drop your hips and lose the ability to continue to provide effective force to the track. You will then be pulling rather than pushing.

    Just allow it to happen and don't worry when it happens (i.e. don't force yourself to be in a certain position at a particular point on the track).

    🙂

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    2belite on #21672

    I agree with JJ's answer, you should take his advice and allow your torso to control your head.
    I am not trying to be rude, but you can't have a good "drive phase" if you can't transition out of it. Sprinting should be seamless, and a good "drive phase" would mean you accelerated to max velocity smoothly.

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    x-king on #21673

    Thanks guys. I'll definetly take it on board.

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    jjh999 on #21674

    …drive phase
    …drive phase
    …drive phase

    (JJ stands in the corner and repeats to himself, "There's no place like home, There's no place like home…" )

    :barf:

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    400stud on #21675

    [i]Originally posted by JJ[/i]
    …drive phase
    …drive phase
    …drive phase

    (JJ stands in the corner and repeats to himself, "There's no place like home, There's no place like home…" )

    :barf:

    I love it JJ. Keep the attitude, it's hilarious and well received 😀 :spin: :tumble:

    Carl Valle
    Participant
    Carl Valle on #21676

    If one has a great "drive phase" but has a bad "transition" into max velocity then drive phase is no longer great?

    Mike Young
    Keymaster
    Mike Young on #21677

    The "head down" position that has been popularized by HSI's group should only be attempted by very elite athletes if at all. It's an attemp to move the COM to a more favorable position for acceleration but it has the head is tucked down, forces cannot possibly be transimitted through the long axis of the body. It is also likely to create a greater rotational moment meaning that it will be harder to come out of it as you stand up. If it were to be done (and I really don't recommend it) the movement of the head would have to be as progressive (moving at the same rate upwards) as the changing body / trunk angles; so that the head would be upright at the exact moment that upright posture was achieved. If the head were thrown back rapidly at any point, it would create huge problems. I'd imagine this is probably what you're experiencing.

    Overall though I'd stick with JJ's advice. Try to keep a neutral head position and drive through the long axis of the body. Head position should be dictated by body angles and body angles should be dictated by the acceleration curve (should dictate the rate of change of body angles) and force application (should somewhat dictate the angle itself).

    ELITETRACK Founder

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    2belite on #21678

    [i]Originally posted by Phoenix[/i]
    If one has a great "drive phase" but has a bad "transition" into max velocity then drive phase is no longer great?

    I know, it does not sound right. What I am trying to say is this; a 100m sprint is all about acceleration, there is positive acceleration and then negative acceleration. We as coaches give names to different segments of the sprint, but in actuality there are no cut off marks. "Drive phase" does not end when we look up. There is no "transition phase", we are constantly transitioning from the time we leave the blocks to the finish line. So in my head you cant have a good drive phase and a bad transition, you were simply having a good run then you made a mistake and jacked up. For example, Bruny Surin was having a great run in the 99 world champs then he took that bad step and jacked up. What should we say; he had a good drive phase, a good max velocity phase, but he needs to work on his deceleration phase.

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    2belite on #21679

    Mike, I know you do some biomechanic work so I am guessing you are the best person to ask this question. Does Maurice have more of a lean from the trunk during early acceleration than most other sprinters or is it just his head position that is down.

    Mike Young
    Keymaster
    Mike Young on #21680

    I don't have any data on it (my biomechanics work is mainly with the shot putters and some sub-elite level sprinters) but I'd imagine it's a little of both (lower head angle and lower trunk angle). This is to be expected since tucking the head down will lower the COM which will go hand in hand with a lower trunk angle. That is, if two individuals (Runer A: tucked head; Runner B: neutral head) of equal power and dimensions were racing with the same race distribution and velocity curve, the one who starts with a lower COM will have to take longer to get to an upright posture because their COM started from a lower position. So at any given point, runner A will have a lower trunk angle that is mostly due to the effect that the head down position has on the total body COM. In theory, this could potentially extend the acceleration (positive) phase because the foot contacts would be behind the COM for a longer period of time (until the person gets fully upright). I hope that made sense. I personally think that it's negative effects would outweigh its potential benefits.

    ELITETRACK Founder

    Mike Young
    Keymaster
    Mike Young on #21681

    I just thought of a more concise way of stating my point from the last post:

    If two runners are progressing through body angles at the same rate, the one with the lowest starting COM position will have a lower position (as seen by trunk angle) until the point where both are running with an upright posture. This of course is dependent on the fact that a runner with a head down position doesn't suddenly throw their head back at some point.

    ELITETRACK Founder

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    2belite on #21682

    What I find amazing is the fact that Ben Johnson had lower departure angles than most of his rivals, but yet seem to be more upright than them during early acceleration. He is one of the few sprinters that maintain a stright line through the long axis of the body during early acceleration. Most of his rivals back then were slightly bent over at the waist and it seem like today's sprinter are bent over even more. John Smith talks about keeping the weight foward and using it like a running back comming through a hole. Could there be any advantage to this? Phisics tells us that force can be better transmitted if we keep a straight line through the body, but it also tell us that the best takeoff angles for gaining distance is 45 degrees, yet nobody would try this in the long jump. Phisics does not always work the same way when it comes to the human body as compared to other objects. So maybe unless you have a great amount of strength like Ben, it is better to accelerate with some bend in the long axis going through the body.

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    jjh999 on #21683

    Re: Greene

    I love how this HSI drive phase has taken on a life of it's own.

    Do you know why John started doing that with Maurice? Because when Mo came to John, he was exceptionally explosive, but tended to "pop up" very quickly in his acceleration phase. Get a tape of the '95 US Championships 100m and you will see what I mean. John used the "head down/drive phase" as a cue to "overcorrect". What happens? Mo blows up in '97 and all of a sudden all the HSI guys are running that way. I could be wrong, but I don't believe that the Nike LA/Early HSI crew of Mitchell, Drummond, et al. were using this technique. It's also somewhat brilliant counterintelligence on Smith's part, b/c now everyone is trying to copy that style that really has only worked consistently for one athlete, and people are failing.
    There is no magic bullet.

    Re:Maurice's body angles and such.

    I've not done a quantitative analysis, but my tape study has shown that Mo is exiting the blocks at a fairly normal angle with respect to his peers, maybe just slightly lower only becuase of his ridiculous strength levels. The key difference, in my opinion, is that when he was at the top of his game, he was exceptionally patient in allowing himself to accelerate.

    Re: Bruny.

    What should we say? He ran 99.9% of the race perfectly. He blinked. That is what happens at that level. No semantics, no catch phrases. He ran one of the greatest times ever run, but head-to-head, Mo was better that day.

    Carl Valle
    Participant
    Carl Valle on #21684

    JJ,

    I agree. This is why one cue may work for more sub-elite people but will plague the big boys.

    When looking into such phases yes they are seemless, only at the elite level. One college meet I saw a beautiful run of a 10.20 with a smooth and seamless stride pattern. Yet to my untrained eye it was too seamless. In efforts to run "perfect" he lowered his watts. Because he stayed relaxed I could not see it. When he got ready by "not trying to not try too much" for olympic trials he ran a 10.09 and made the team for his country.

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