Explained: avoiding overtraining

It’s a fact of life that if you do what you’ve always done, you’ll get what you’ve always had.

Nowhere is this truer than in endurance sports like triathlon, as grinding out the same workouts at the same intensity won’t help you achieve that new PB. To do that, you have to push your body a little bit harder in training in order to stimulate the physiological and biochemical changes needed in the muscles so that you can swim, bike and run faster for longer.

But here’s the rub: when you’re already training hard, how can you be sure that any increase in training intensity or duration – overreaching – will make you fitter and faster rather than simply leaving you exhausted and drained, or overtrained?

Overreached or overtrained?

The answer, of course, is by trying to measure how much overreaching your training is producing and knowing how to tell when excessive overreaching may be tipping you over the edge into an overtrained state. Unfortunately, it’s easier said than done because this isn’t a well-researched area, mainly because no sports science ethics committee would consent to a study allowing deliberate overtraining to take place. Moreover, the studies that have been carried out in this area have tended to be retrospective in nature, or have induced a training overload over a period of weeks rather than months – something that’s more in the realms of overreaching rather than overtraining.

It’s true that novice triathletes are less likely to have the experience, desire or physical capacity to work hard enough to provide long-lasting fatigue and so are at lower risk of overtraining. Equally, elite triathletes tend to know their own bodies better and are more likely to be able to identify the difference between just being tired or actually being in danger of overtraining. Ideally, however, it would be great if there was some objective method of measurement.

How to measure overreaching

Some studies have investigated whether it’s possible to measure how much overreaching is taking place as a consequence of increased training load and whether there’s a risk of overtraining as a result. For example, one study looked at changes in physiological, biochemical and psychological markers of overreaching in 16 experienced triathletes. The triathletes were split into two groups and performed either four weeks of overload training (290% greater training load than normal) or normal training. In both cases, measurements were made after a two-week taper.

After the four weeks of training but before the taper, the normal-trained triathletes improved their 3km run time significantly (by 3.0%) whereas the intensely-trained group ran 3.7% slower, indicating a state of overreaching. However, once the intensely-trained triathletes had tapered, their times improved by 7.0%, which meant they caught up and slightly surpassed the normal-trained triathletes. Unfortunately, none of the biochemical or physiological markers tested were considered effective indicators of overreaching; in other words, the only accurate indicator was a drop in physical performance.

Problem solved?

The problem of a lack of an adequate test to detect overreaching and prevent overtraining has been a thorny one. But now brand-new research on triathletes makes for encouraging reading.

French researchers separated 24 highly-trained triathletes into an overload group and a normally-trained group during three weeks of training, in which they underwent physiological, biomechanical, cognitive and perceptive (self-evaluation) testing and monitoring.

Eleven of the triathletes were diagnosed as overreached after this intense training period, and when test results were statistically analysed it seemed that increased heart rates and blood lactate for a given speed/power output, along with changed running biomechanics and an increase in perceived effort, explained most (98.2%) of the overreached state. In contrast, levels of stress hormones and muscle breakdown markers – the things commonly believed to be linked to overreaching – were not deemed to be relevant. In fact, further analysis showed that blood lactate and elevated heart rate alone accounted for nearly 90% of the overreaching.

This is interesting because, if confirmed, blood lactate and heart rate for a given speed or power output are easily checked. Accurate heart rate monitors are already cheap while portable devices that measure blood lactate are becoming more affordable each year – some triathlon club coaches may already use them. This will make it increasingly easy for triathletes stepping up their training intensity/volume to ensure they do it in a productive and safe way, without the risk of becoming overtrained.

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