In Steve's last article he examined the effects of lower steady state training (UT2), the benefits of which come in the form of changes within the working muscle, enabling an efficient use of consumed oxygen. Prolonged low intensity training is heavily implicated in stimulating chronic changes such as the improved use of muscle fibre types, where 'fatigue resistance' seems to be the secret behind 'mileage' oriented programmes. But many endurance sports are putting up the effort to a minimum of 'upper steady state' or UT1 training . The question is why and is this the best thing to do?

Summary of FISA guidelines

Much interest in applied sports physiology is directed toward physical 'capacities'. These upper limits represent the potential for work output. In endurance based sports the focus is upon the limitations of the body to perform aerobically. Capacities of the aerobic systems can essentially be divided into work that can be performed before lactate begins to accumulate, and work that can be performed before the intake of oxygen begins to fail to meet the work demand.

Strangely, lactate accumulation will occur before the ability to consume oxygen fails, but this is due to the fact that the ability to clear lactate is not governed solely by the availability of oxygen, but more so by special transporters on the muscle membranes. The point beyond which further increases in work result in an accumulation of lactate is such a limitation, and explains why it is referred to as a threshold.

The lactate threshold is also commonly referred to in rowing and elsewhere as the anaerobic threshold or AT (although this term is now outdated). This is a significant marker as it is the physiological measure most highly related to 2000 metre rowing performance. The point at which it occurs is also used to establish training intensity zones for the GB team through physiological testing at the British Olympic Medical Centre.

The lactate threshold is also commonly referred to in rowing and elsewhere as the anaerobic threshold or AT (although this term is now outdated). This is a significant marker as it is the physiological measure most highly related to 2000 metre rowing performance. The point at which it occurs is also used to establish training intensity zones for the GB team through physiological testing at the British Olympic Medical Centre.

The threshold training zone occurs at an intensity equivalent to the heart rate zone of approximately 10 beats per minute above the lactate threshold. In most trained athletes AT occurs at around 80-90 per cent of maximum heart rate, although this varies widely. It does however, correspond to the exercise intensity at which holding a conversation becomes difficult, since breathing becomes rapid.

Threshold or 'tempo' sessions should be brisk efforts in which the rower is moving strongly. Breathing is quite hard, the muscles will feel uncomfortable, but this should not be an all out effort. A good degree of control should be maintained, which is why AT sessions lend themselves particularly well to work on the ergometer. The most common mistake made is to exercise too hard, and as a result the effort becomes too anaerobic. Since the aim is to train .aerobically the intensity must not be too high.

It is increasingly fashionable in many endurance sports to include threshold sessions in the training week in an attempt to shift the lactate threshold to a higher intensity. The evidence of the efficacy of threshold training seems to be that it has a particularly strong tendency for improving endurance capacity. The foundation for such training relates to the fact that this zone represents the upper limit for sustainable steady state exercise. The body is exposed to higher levels of lactate than during UT2 or UTl training and also demands a greater consumption of oxygen.

Therefore, the effective training stimulus seems to be to clear lactate at its highest rate under aerobic conditions. With this in mind it is easy to see why this has been unearthed as a very attractive training level, and because the science is fairly concrete, is less likely to be on next yeai s scrapheap of training trends.

Threshold training is usually of 20 to 40 minutes duration, which may comprise 2 to 4 equal blocks of work (e.g. 3 x 8 minutes). Evidence suggests that there is no difference in the training adaptation from continuous Vs to intermittent AT training, so giving opportunity for imaginative and varied sessions. The periodisation of AT work is an area that is neglected in many endurance based programmes in many sports. There seems little sense in designing a training programme that has the same amount of AT training in November as in March, for example.

There should be a clear progression of AT work across the months that gives the athlete time to build up the tolerance to higher intensity training volume and phases toward exercise that is more specific to performance. In some quarters of coaching and training, it is believed that the greatest improvements in endurance capacity (specifically the lactate threshold) are achieved if AT and higher intensity (race specific) work are preceded by a pro longed phase of lower intensity training. This is very difficult to show scientifically because good quality longitudinal studies are thin on the ground. However, this method of low-to-high intensity periodisation has been used to great effect in the vast majority of athletic training programmes. To offer a different slant, one wonders whether it is simply the variety that such a programme offers that is the key to its success.

But while we all consider flipping our training programmes on their heads, it would make sound physiological sense to design a training programme that aims to make the most of an athlete's potential the closer you get to a competition phase. Therefore, the gradual phasing of AT into a programme throughout the year, being at a maximum during the regatta season, would be a sound method of maximising an athlete's physiological capacities.

Example phasing of AT training

Note that the total time spent in AT increases slowly across the weeks

Editorial by Steve Ingham