I’ve often said that the practice of “tapering” — reducing training in the days and weeks leading up to a big race — is much harder to get right than most people think.

One reason for this, I think, is that tapering is both a physiological process and a psychological adjustment. I believe it was David Costill, a researcher at Ball State University, who first used the term “tapering” in the physiological sense. Research he conducted in the 1970s showed dramatic performance improvements for swimmers who significantly reduced the volume of their training leading up to an important competition. This seems almost self-evident to us now, but it was not always so obvious. Furthermore, it’s not trivial to figure out the details of effective physiological tapering. Should intensity increase during the period of reduced volume? Does the tapering strategy depend on individual differences in adaptation rate? Do some people “de-train” more rapidly than others?

And then there’s the psychological side of tapering. Ideally, an athlete arrives at the starting line with high confidence in their fitness and readiness. Many athletes derive that confidence from the memory of recent workouts that “proved” they were fit and ready. Both athletes and coaches are prone to insecurity, and do hard workouts late in their preparation to prove to themselves that they are capable of supreme efforts. The problem occurs when the need to test fitness conflicts with the need to rest and recover. I would guess that many more performances are compromised by trying to fit in that last great workout than are compromised by de-training from resting.

Probably the best way to address this is to have a coach who is willing to rein in any tendency to train too hard in the final days or weeks leading up to the race, all the while telling the athlete how fit he or she is.

One thing I’ve been thinking about a lot lately is how the normal training volume affects the ideal slope of the taper. In other words, if an athlete runs 100 miles a week, is their taper longer (and steeper or more shallow) than an athlete who runs 60 miles a week? And if an athlete is running 30 miles a week, should they taper at all? I’m not familiar with any studies of this issue, but to me it seems quite important when planning a taper.

I would guess that if you aren’t doing a lot of running in the first place, you shouldn’t expect much performance benefit from tapering, compared to, say, just taking a couple of easy days before a race. Another way of saying this is that the performance boost from tapering comes from super-compensation for an extended period of hard training. If there wasn’t much training the first place, then there’s no super-compensation.

Of course, even if you’re only running 10 miles a week, there’s probably a psychological benefit to having a coach around who’s willing to rein you in and tell you you’re in great shape.