What's the more common cause for bad performances - overtraining or undertraining?

Overtraining and complacency.

Gotta vary up the routine. Work smarter never harder.

Neither! More that you train wrong with not correct balance in pace and important factors for the result.

The Guru of running

I'm going with under. There just aren't very many people these days doing the volume you need to get overtrained. People are mistaking normal tiredness for being overtrained.

If we're talking specifically about top level DI athletes and pros, probably overtraining.

If we're talking about the running population in general, absolutely and without question undertraining. For one thing, almost all high school runners are undertrained. That alone has to account for millions of bad races per year. Then if we throw in road races, those events consist almost exclusively of undertrained individuals.

Of the two choices, I'd say over training is the more common cause for bad performances.

You always hear of runners slowed by injury. That doesn't come from under training.

under wrote:

If we're talking specifically about top level DI athletes and pros, probably overtraining.

If we're talking about the running population in general, absolutely and without question undertraining. For one thing, almost all high school runners are undertrained. That alone has to account for millions of bad races per year. Then if we throw in road races, those events consist almost exclusively of undertrained individuals.

I agree with what you wrote.

One thing I would also mention is that some people above said "very few runners are doing enough mileage to be over trained." But overtraining can be a result of too many workouts, or not enough rest days between workouts. It is possible to be over trained on very low mileage.

Star wrote:

Of the two choices, I'd say over training is the more common cause for bad performances.

You always hear of runners slowed by injury. That doesn't come from under training.

You don't hear about runners slowed by undertraining because those runners either don't care or don't realize that they are being slowed. Certainly the thousands upon thousands of people who run 20+ minute 5Ks in local road races would be faster if they ran more. Most high school kids who are running 30mpw think they're training hard just because they lack a frame of reference, but they would perform better with more training.

Stress in life.

Runnerdnerd wrote:

I agree with what you wrote.

One thing I would also mention is that some people above said "very few runners are doing enough mileage to be over trained." But overtraining can be a result of too many workouts, or not enough rest days between workouts. It is possible to be over trained on very low mileage.

Here's where it gets tricky: overtraining in the short run can be a result of undertraining in the long run. If a high schooler doesn't run much during the summer, then he shows up at practice and gets injured when he tries to ramp up the mileage quickly, you could say that he was overtrained in that he got injured from increasing mileage too quickly, but ultimately he was really injured because he was undertrained, as his lack of base led him to be unable to handle the in-season mileage.

So whether overtraining comes from too many workouts, or not enough base is the question for a given "overtrained" athlete.