An alternative to running, which also uses the big leg muscles, is cycling. Its main benefit in comparison to running is that, like swimming, it is largely impact-free. This helps reduce your chances of getting injured. On the other hand, cycling does very little for the muscles of the upper body, can be dangerous (you can’t easily fall off a swimming pool) and requires you to lash out a lot of dosh on a decent bike. As with all aerobic exercises, you need to get your heart rate into the training range for at least half an hour to make it worthwhile. Thiscan be difficult in a town because of traffic. Ideally, your cycle route should consist of a country road or park with plenty of hills to help build up leg strength — or you can go to a gym and use an exercise bike with variable resistance.
The rhythm that you should aim to achieve while cycling is about 8o turns of the pedal per minute. If your bike has gears, this will probably mean that you can’t use your top gears except when going down hills (using the top gear on flat stirfaces increases strain on the knee joints by a considerable amount and can cause injury). The best way of judging if you are at the right speed or not is as follows: if your legs become tired before you get out of breath, you are in too high a gear and are using your leg muscles too much, whereas if you get out of breath but your legs remain strong, your gears are too low.
The only difference between walking a distance and running it, I have been told, is the time it takes you to do it. In terms of energy used and muscle strength gained, this may well be so, though I doubt if there is a direct comparison in cardiovascular improvement. If you are training for SAS selection, you are going to have to get used to a lot of walking, over hills and carrying a rucksack, but that is different from the exercise walking advocated by a number of gurus nowadays. Personally, I find it hard to take seriously the sight of grown men and women striding round my local park wearing lurex tights and determined expressions. There is no doubt that walking improves your fitness, but by nothing like the factor that you will achieve by running, swimming or cycling.
Like walking, aerobics — of the kind practised at lunch-time classes — undoubtedly makes you feel better. As a form of exercise, however, it is going to leave you a long way off the standards you’ll reach on a MMA Fit programme. Don’t neglect it altogether, though, as the most enjoyable aerobic exercise of all is good old bonking. It would be extremely difficult to get your heart rate into the training range for a full 30 minutes, but you can have a lot of fun trying. I would suggest using the more athletic positions, possibly in a hammock, to give yourself the best shot at it (warning: don’t let your partner catch you measuring your heart rate during sex as this may seriously damage your health).