The Overtraining Threshold
Throughout the Base and Build periods the workload should be just great enough to produce stress marked by fatigue and adaptation, but not so high that the overtraining syndrome results. The level at which overtraining symptoms first appear is the “overtraining threshold.” The overtraining threshold is a moving target. The workload that causes overtraining when fitness is low may be easily tolerated when fitness is high.
For experienced athletes there actually are times when the overtraining threshold is exceeded in order to produce the highest levels of fitness. This is called “overreaching" and is illustrated in the accompanying graphic. The key here is to reduce the training load at the right time while overreaching so that the overtraining syndrome doesn’t occur. If it does it may well take several weeks to recover. This is rare but there are some athletes who push themselves hard enough to achieve it. Most of us will back off long before we get to that level.
As adaptation occurs with improving fitness, the overtraining threshold rises. In other words, it takes more workload to overtrain the athlete as fitness improves. The workload must rise if fitness improvement is to continue. Most athletes recognize this phenomenon and allow for it by increasing the number of intervals within a workout, or by extending the length of a workout, or by doing repeats at a greater effort. The problem is that most athletes try to rush the process, but it’s simply not possible to speed up the changes that happen at the cellular level short of using drugs. The human body adapts to changes in workload slowly and steadily. And each individual athlete has his or her own unique rate of adaptation. The trick is to discover what your rate is and then pay close attention to it when determining training workloads. This isn’t easy. It is best to err on the conservative side.
How can the overtraining threshold be identified? It’s tough to nail down, in part, because it’s always changing, but also because there are no universal and absolute standards. For example, I can’t say what a certain resting heart rate—either high or low—means for your level of overtraining. That must be determined individually. I’ve found, however, that there are several categories of markers that may predict when you are exceeding your overtraining threshold. They are:
+ Fatigue which doesn’t go away with 48 hours of low workload or even time off from training. The legs feel tired or there is general body weariness that lingers even after taking it easy for two days.
+ Little control of emotions — evidence of anger, feeling sorry for yourself, moodiness, depression, grumpiness. In short, you are hard to live with. A spouse or roommate may be the first to recognize this.
+ Performance declines. For example, you are slower at a given heart rate, or for any given speed, heart rate is higher than usual.
+ Self-confidence declines. This may be the best marker, but it’s hard to assess. One way to do it may be in the athlete trying to visualize accomplishing a very high workout or race goal. If it seems out of reach and farfetched, self-confidence may be low.
When any of these markers show up and linger for more than three days, there’s a good chance that the overtraining threshold has been exceeded. At this point the workload must be reduced immediately until you are back to normal. Then take time to evaluate what level of workload produced the problem, and make adjustments as you start back into higher workloads.
By learning to recognize your overtraining threshold and keeping the workload below it while designing the season around your limiters and strengths, you’ll improve race performances both in the short and long term. That’s smart training.