Cross training: could it help you achieve that new PB?

Cross training, the use of a different method of training to your normal activity, has been around for years. For example, rowers have not only used weight training as an alternative mode of exercise to improve performances at the regatta but also employ endurance activities off the water, such as running and cycling, to complement their normal programme. Similarly, swimmers use land training to help their in-water performance on race day. More recently, cross training has gathered pace because of the greater interest in multi-disciplinary sports such as quadrathlons, triathlons and biathlons. Here you have to train using a variety of exercise modes or you will simply not be training according to the demands of your event.

The whole concept has spread further afield, however, so that you find dedicated runners sometimes cycling in an attempt to run their races faster, or football and rugby players cycling or using rowing machines instead of performing conditioning workouts on the legs that are going to carry them round the field of play, or even non-swimmers donning buoyancy aids and jumping in at the deep end to run through the water.

It's non-specific, say the critics

The main argument against cross training is that the workout does not mimic the demands of the athlete's sport, and one of the golden rules of any training schedule is that the training should be specific. This argument is based on the principle that the training you do will not only condition the appropriate musculature when you go out to compete, in terms of physical and biochemical properties, but will also and equally importantly train the appropriate neuromuscular pathways of the main activity. In other words, there is little transfer in the skill of the activity, whereby messages are sent from the brain via nerves to the muscle fibres.

Well-skilled performances can fire not only the correct muscle units for that performance but can also fire them at the right time in a coordinated fashion enabling more effective muscular contractions. If you cross train, you will not be learning the correct skill patterns for your sport. For example, cycling training will train the muscles to be better at cycling but won't necessarily make them better at running or swimming. As a running coach once said: 'If it don't involve running and it won't make you run faster, then it ain't worth doing in my book'.

This may make sense, but there are many practitioners who argue that it is not necessarily the case. In fact, their arguments are also supported by some of the research literature from the (sometimes conflicting) world of sports science.

For instance, consider the heavyweight prop forward at the beginning of his pre-season training period. He has a couple of desires (once the reduction in alcohol intake has been attended to): one is to lose a bit of body fat and the other is to increase cardiorespiratory fitness (or endurance). He may well need to improve other aspects of fitness such as flexibility, strength, power, speed and so on, but these may be addressed in more detail once a base has been established.

The most specific way for our man to develop endurance will be to perform lots of running, which will help him to lose fat as well. The trouble is that, being heavy, even if he runs on grass (which can be quite hard and unforgiving) and has well-made shoes, there is a fair risk that he will pick up injuries to his muscles and joints if he crashes straight into the sort of running mileage associated with Liz McColgan. It would make sense for him to vary his workouts, with some running, cycling, to give his legs a rest from the pounding, along with some rowing and swimming. All these forms of activity will help him lose body fat and increase cardiovascular endurance, and with a variety of workouts there is less chance of overuse injuries occurring.

In fact, it is this avoidance of overuse injuries that is one of the strongest arguments in favour of cross training. Extra endurance work can be performed, with less strain placed on the same muscles and joints, which may indeed be getting an active rest, while at the same time there is still an adequate workout for the heart and lungs.

The story is similar for the endurance runner. It sometimes happens that an athlete would like to do more training than his or her current level but knows from past experience that once the weekly mileage creeps above a certain point, say, 50 miles a week, the injuries start to come thick and fast. Non-specific training would be a way of increasing the training level with a reduced injury risk. Cycling will help to work on the heart and lungs without pounding the joints. Aquarunning would be an even better alternative because it not only eliminates the pounding but has a similar movement to running on land, thus keeping specificity.

But how useful are such methods for running performance itself? Cycling has been shown to be very good for running when controlled studies have taken place. One such study at California State University found that runners who were split into two groups, one group running only and the other cycling only, both at the same intensities, performed just as well in a running test after the nine-week training programme regardless of the mode of exercise. The study indicated that for runners tough cycling was a good way of not only maintaining but actually improving fitness. However, running is not necessarily as beneficial for cycling; the increase in cycling fitness in the group who ran only was not nearly as marked as the improvement in running fitness.

Much work has also examined aquarunning. The general consensus of recent research is that aquarunning will not give the same intensity as normal running but is still a suitable alternative, given its low-impact nature. It is worth noting, however, that water running without a buoyancy aid is more effective than using one. Similarly, a study from Wisconsin University looked at in-line skating compared to running and cycling and also revealed a difficulty in trying to keep the intensity as high in the less-traditional form of exercise. Heart rates and oxygen consumption at set lactate levels were much lower in skating than in running and cycling.

Watch your heart rate if you cross train

If you do cross train and use heart rate as your guide to intensity, it is important to remember that maximum heart rates, and therefore training ranges, are likely to vary according to your mode of exercise. You can normally expect higher heart rates while you run as opposed to cycling or rowing. The reason is quite simple. When you run, you lug your body mass around with you, while in rowing and cycling you are seated and your body mass is supported. This makes the energy demands of running a little higher. Although there is enormous individual variation, it is usual for heart rate to be about 10 beats a minute higher in running than in cycling and this should be borne in mind when selecting training intensities.

If you double up training sessions within one day and like to perform both strength and endurance training, the traditional advice would be to perform the strength session first and the endurance session later. This makes sense as you be would fresh for the quality workout, whereas it wouldn't matter so much if you were a bit tired at the start of the endurance workout because that would only add to the endurance aspect.

However, a recent study from Kennesaw State College, Georgia, revealed that there was little difference in the improvement of both strength and endurance when one group performed the strength workout before the endurance while another group did the reverse. This research suggests that it makes little difference which session comes first. Cross training certainly makes sense for some athletes, and I've given a few examples. If you're an athlete who trains moderately with little risk of injury, then more of what you're already doing is the best approach. However, for the serious athlete who wants to win, cross training could be a way to increase the amount of training with increasing the chance of injury. Apart from that, it might even make training, dare I say it, more enjoyable.

Joe Dunbar