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More efficient running style

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jonp Dec 2013 9:48am, 23 Dec 2013 4,496 posts	Quote Pin jonp Let's try that link again... http://www.youtube.com/watch?v=6Pv-qCjYgjM
Canute Dec 2013 12:08pm, 23 Dec 2013 835 posts	Quote Pin Canute Jonp Thanks for posting that video clip. In part, the art of running well is having a helpful mental image. For me the most helpful mental images are consistent with the laws of motion. I spent some time trying to make sense of the Pose concepts of fall and pull. The laws of motion, together with observation of videos of other runners and my own sense of what I am doing, confirm for me that the concept of fall makes little sense as the COG rises steadily from mid-stance to mid-flight. However the concept of pull is a little more useful. A coordinated contraction of hip and knee flexors does pull the foot towards the hips. The video shows very precisely coordinated flexion of hips and knees. Nonetheless, as you point out, lifting the foot cannot elevate the centre of mass. So when seeking to identify the essential requirement for getting airborne, the crucial question is what ‘lifts the hips upwards’ This cannot be a pull as there is nothing pulling the hips from above. In fact it is a push from below. The famous (but now hard to find) words of Usain Bolt, ‘Get tall, knees up, dorsiflex, get your toes up, plant, push again’ made it clear that Bolt believes he pushes after planting his foot. These words were discussed on this thread in March 2012. They have now disappeared from this thread, along with the original U-tube clip, though they have been preserved for posterity on various blogs (eg On Tim Huntley’s blog in his reply to Ken Shaffer. http://myathleticlife.com/2012/02/pose-running-sprinting/) The recent Spanish study that we have been discussing here showed that short time on stance is assorted with greater efficiency. According to the Law of Conservation of Momentum, a short time on stance must be associated with a strong push. This strong push will help create a large stride angle, and thereby lead to an association between stride angle and efficiency. I think that is the first conclusion to be drawn from the study. Once the push has got centre of mass (including the hips) moving upwards, pulling the foot towards the torso by flexing hip and knee produces an additional increase in stride angle. This folding of the swing leg decreases the moment arm of the swinging leg (sometimes described as ‘the length of the lever’) and produces a further increase in efficiency. That is the second lesson from the study, though I think it is the icing on the cake. These principles have been known for years, but it is interesting to see that the Spanish study provides evidence in agreement with the principles. I think Pose drills help refine the coordination of the pull of the foot towards hip (which is the icing on the cake) but Pose fails to of emphasize the cardinal role of the push.
jonp Dec 2013 1:14pm, 23 Dec 2013 4,497 posts	Quote Pin jonp Don't really disagree with any of that Canute. I certainly don't deny (and I would hope most other pies coaches don't) that a push exists. If we are elevating the com, and studies show somewhere between 40-50% of that is elastic return from muscle tendon elasticity then the other 50 must be muscular contraction, simples really. A push exists, but from a Pose point of view we don't put conscious focus on that part, mainly because the timing and coordination of the point when it has to happen optimally is better developed through drills (as in video above) and plyometric exercises, strength work etc. From a "mental" point of view, it's easier for people to focus on their hips lifting upwards with the foot lifting as it releases, rather than focussing on pushing against the ground to lift the hips followed quickly by a pull of the foot - irrespective of where the force is actually applied (I.e. the ground). Or in other words, it pays to be a bit mental if you want to run
jonp Dec 2013 1:15pm, 23 Dec 2013 4,498 posts	Quote Pin jonp Pies = Pose LOL
Canute Dec 2013 4:26pm, 23 Dec 2013 837 posts	Quote Pin Canute Yes, it pays to be mental, in a good sense. On the whole, I agree that for distance runners (though not sprinters) it can be helpful to have mental image of getting off stance with a quick, light pull, even if this pull is only ‘the icing on the cake’. I have learned a lot from Pose and think that on the whole it offers a good approach to help recreational runners to get off stance quickly, though the tendency to under-emphasize the forces involved creates a potentially misleading view of the risk of injury.
jonp Dec 2013 4:48pm, 23 Dec 2013 4,500 posts	Quote Pin jonp For a good majority of people their running style is a high injury risk anyhow (what was, 75% of runners get injured every year?). So I think (and found) that for most, if they approach improving their style in a sensible manner using Pose or otherwise, then they'll benefit more than any risk.
Canute Dec 2013 5:08pm, 24 Dec 2013 838 posts	Quote Pin Canute Maybe the most important consequence of hip flexion during swing is reduced risk of injury. In the recent discussion of the study that found that large stride angle was associated with greater efficiency we discussed two factors that contribute to large stride angle: stronger upward push off stance and coordinated hip and knee flexion that lifts the foot towards the hips. A recent study from University of Kentucky provides another reason why hip flexion might be beneficial. The researchers examined the aspect sof running mechanics that predict reduced impact peak and loading rate. Thye found that a higher position of the thigh at mid-swing predicted lower loading rate after foot-strike, and speculate that increased hp flexor activity during swing ultimately decreases the downward velocity at landing thereby generating a smaller impact force. I find this a little counter-intuitive, but that is what the data revealed, and in fact it is consistent with my own sensation of a lighter footfall when I have a flexed hip and knee at mid-swing. It is plausible that smaller impact and/or decreased loading rate might create less risk of injury.
_Zen Dec 2013 10:55am, 25 Dec 2013 17 posts	Quote Pin _Zen Some interesting points here on hip/knee extension drop off as you age ... pponline.co.uk
Canute Dec 2013 11:56am, 27 Dec 2013 839 posts	Quote Pin Canute Zen, That is an interesting article by Owen Anderson. The three features he identifies: short time on stance; hip and knee flexion during swing and a large hip extension in late stance are all clearly associated with efficient form. Of these three features, the large hip extension is perhaps the most difficult to achieve through conscious intention. His advice to push back strongly is not easy to put into practice without delaying time on stance. The problem of shortening of stride length with age is one I have been struggling with for several years. Although my loss of stride length is associated with less dynamic range of motion at my hips, the puzzling thing is that it is not associated with an appreciable loss of efficiency of utilization of oxygen. It appears to be associated with less powerful muscle contraction and therefore less use of oxygen, so the efficiency of oxygen useage has not decreased very much. I do not need any extra oxygen to cover a given distance. It just takes me much longer. However, despite a program of weight lifting that has re-established the strength of my younger days, I have not been able to recover the necessary power. My joints are now much more fragile, and it seems as if to protect my joints, my brain will not allow my muscles to apply large forces rapidly.
richh Dec 2013 1:29pm, 27 Dec 2013 656 posts	Quote Pin richh Canute, Interesting theory about the brain protecting your more fragile joints. Are you sure your weight lifting has strengthened all the muscles relevant for running? I'd think even one sub-par muscle could be the link that weakens the entire chain.