> Think of it more as a spring rather than a damper. ...in which case it's definitely illegal under IAAF rules. BTW, even the dreaded "heel strike" isn't as b

> Think of it more as a spring rather than a damper. ...in which case it's definitely illegal under IAAF rules. BTW, even the dreaded "heel strike" isn't as bad as many seem to think. In the article I cited in another comment here, they actually found that heel striking is more energy-efficient. Other studies I've seen have suggested that heel striking is more often a symptom of another problem than a problem itself. It might or might not be ideal, but among dozens of other mechanical issues people can have - e.g. overstriding, pronation/supination - it's only one part of the picture and IMO is often a distraction from any given runner's real issues.