Nothing to do with physics, the runner themself exerts more force.
Yes he exerts more force (well more energy anyway) to compress the shoe which happens more slowly than it would barefoot so the force exerted onto the body will be less than it would if the same energy were applied over a shorter distance/time with either a thinner sole or no sole at all. The problem with cushioning is that it may alter your running style so that you run with a gait which is not natural for you and so leads to "unnatural" stresses and strains in the legs and so leads to injury.
I have got on very well with Hokas.
1) allow you to do as many miles as you have time for as recovery is much better (less fatigue)
2) no more Plantar Fasciitis
3) great for quick descending on tracks and rough ground
4) they don' t encourage heel striking - good for forefoot running
5) you can run "over" rough ground - rather than through it
6) good conversation starter!
But - you do need to run in other shoes as well as your feet will get rather used to them and when you do go back to thin soles you do notice.
For me the grip is fine on all but very slippery grass/mud. Just been around 3 peaks in them today and didn't slip once.
I should say that I got the shoes after breaking my Fibula in April. They allowed me to get back running within 6 weeks. 12 weeks later I was running the L100 and they got me to the finish way quicker than I ever expected. The idea that they might cause you more injuries is odd. But it is down to personal choice. Just try them and see!
But that assumes that the same force is applied when barefoot, the study by Lieberman proved that wasn't the case. I'm not necessarily advocating either thing here, just pointing out the findings of the study. Impact forces were greater and peaked higher with thicker soles. The brain adjusts to run light in anticipation of hurting the foot, a bit like touching something hot and recoiling. At least, that is my understanding of it.
@Hill_Runner on twitter
Suggestions, please, where to buy Hokas.
Begin afresh, afresh, afresh.
Likeys have them. http://www.likeys.com/
Hills and Guinness!
Thanks, Steve, great tipoff. I have been looking at their sizing chart, & it says that with feet 260mm long I need a size 8UK. In Inov8 Flyrocs I take a 9.5, but fill up some of the space with Sorbathane & Noene insoles, which obviously I wouldn't need with Hokas. In Inov8 Mudclaw 333s with just Inov8 insoles I take a 9. Everyone seems to feel they need a size larger than their normal shoe. Any comments would be helpful, before I take the plunge!
Begin afresh, afresh, afresh.
Castleberg in Settle has Hokas. I've seen them there :w00t:
Poacher turned game-keeper