I’m fascinated by discussions of limits, whether social, physiological, or scientific. There are some fine books on the subject, and there is an entire literature of urban legends around what people are alleged to have said about limits that turned out not to have existed, from music to patents.
With the preceding in mind, there is a paper in the October issue of a sports physiology journal (“Are There Limits to Running World Records?”, Medicine & Science in Sports & Exercise) that gets to this issue in a running context. The authors argue that most prior work in the area of limits in performance among top athletes competing at middle- and longer-distance running have used the wrong model. They have used a linear model, as opposed to a more “biologically sound” S-model, which these authors bring to bear. Their conclusion: We are rapidly reaching competitive limits among male and female runners, and we already may be there in one female event, the 1,500m: