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Sep 2013
9:14pm, 17 Sep 2013
19,041 posts
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eL Bee!
Canute - as you have looked in detail at this maybe you can throw some light on how the researchers have actually defined heel-strike, midfoot and forefoot landing, because as terms they are incredibly 'wooly'
To me the important thing is not what part if the foot is weighted, but WHERE in relation to the body's Centre of mass, the foot is weighted.
Have they specific criteria for how they have labelled the different types of landing?
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Sep 2013
9:15pm, 17 Sep 2013
19,042 posts
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eL Bee!
""......what part OF......""
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Sep 2013
9:42pm, 17 Sep 2013
4,482 posts
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jonp
Hey FR, speed isn't the main factor in energy consumption, distance itself is, based on W=Fd. I could run a 10k in 30mins (I can wish anyway) or 1hr and I would consume a very similar amount of Joules over the distance.
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Sep 2013
9:47pm, 17 Sep 2013
16,830 posts
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FR
jonp, my understanding is that you are correct in pure mechanics but when applied to the human body, as Canute rightly states walking has no flight stage, so you're not lifting your bodyweight with walking, the difference is large.
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Sep 2013
9:48pm, 17 Sep 2013
16,831 posts
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FR
...and inefficiencies increase with pace, e.g. one of the reasons Bolt can't maintain that pace for any reasonable distance.
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Sep 2013
9:58pm, 17 Sep 2013
4,483 posts
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jonp
You do lift your body (Or centre of mass) when walking, as I described earlier, just you don't lift it airborn.
Strictly speaking, no net work is done when you hop on the spot or lift up and down on your toes, because your COM is in the same place as it started after each hop/lift. Same as if you are standing and holding a heavy weight in the air you are doing 0 work. Pure physics wise anyway. But at a bio-physics level, as I understand, work is done to constantly signal muscle contraction.
I think it is true to say more energy is consumed running over 26 miles when running, but I don't expect the calories burnt are so huge,y apart.
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Sep 2013
10:04pm, 17 Sep 2013
783 posts
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Canute
ElBee,
In the Spanish study they visually identified the part of the foot that made initial contact with the ground at foot strike.
I think that the point at which weighting occurs should probably be defined in relation to when vertical ground reaction force reaches a peak, but this requires force plate data.
Sorry for the lack of detail. I am about to depart for a conference in Switzerland and will be back on Saturday
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Sep 2013
10:46pm, 17 Sep 2013
4,484 posts
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jonp
FR, Bolt is running very fast, therefore his rate of work (or power requirement) is greater. His aerobic system cannot provide that rate of work, and therefore he can't run that fast for that long.
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Sep 2013
10:47pm, 17 Sep 2013
4,485 posts
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jonp
But I could run say 100m in double the time and my power requirement would therefore be less, but overall the work we both do would be the same.
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Sep 2013
5:05pm, 19 Sep 2013
3,728 posts
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Jhuff
Has anyone here heard of POSE?? 
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