When you initially get started in training, the intensity of your exercise sessionsought to be exceptionally soft enough that your particular body can get used to the idea of continuing destruction followed by repairing itself. For example, middle distance and endurance runners, which events require a combination of aerobic and anaerobic energy, need to ensure that their training sessions provide the specific exercise intensity levels required to enhance performance.
The Right Level
In the past, some less informed coaches have applied the adage of 'no pain, no gain' when working with athletes, so intimating that without a training session was of maximum effort, and resolved in fatigue, there was little chance of it being of any benefit. In fact, scientific evidence has shown that continuously trying to train at a high intensity quickly causes both physiological and psychological fatigue, not improved performance. While there is both scope and a need for high-intensity sessions, these must form only a part of a training program. Conversely, if training is too easy, it is inadvertently to produce a meaningful training effect. Therefore you need to establish a mix of low-, medium- and high-intensity training that produces optimum improvements in performance, allows scope for recovery and does not result in overtraining and chronic fatigue.
Heart Rate Monitors
One technique that can help is the use of heart rate monitors. There are many recommendations on the exact heart rate zones, but in general it is accepted that at an exercise rate below around 60-70 per cent of maximum there will be minimal training effect. The aerobic energy system is best developed at an intensity of between 70 and 80 per cent of maximum heart rate. High-intensity training, developing a combination of the aerobic and anaerobic systems, occurs at between 80 and 90 per cent of maximum heart rate, while short-term near maximum effort work occurs at rates in excess of 90 per cent of maximum.
It is important to be aware that heart rate tends to creep up gradually with time, so it is best to start a session at the lower end of the range. Maximum rate also decrees with age (usually estimated by subtracting age from 220) and this needs to be factored in when converting a heart rate value to a percentage of maximum.
Finally, heart rate monitors are only a guide to training intensity and many athletes exercise perfectly well without them, often by getting a feel for the different intensity levels and the body's reaction to a training session.