Roadhoggs Leicester AC
Road running captain, Mark, leads speed sessions a the Saffron Lane athletics track. The track was re-laid not so long ago and is a pleasure to run on. There are changing and showering facilities available. Tickets cost £3 and can be obtained from the clubhouse or from Aylestone Leisure Centre (on the corner of Saffron Lane and Knighton Lane East). Sessions take place on Saturday mornings at 10.30 (not if we've got a race the following day) and Tuesday evenings at 6.00. Contact Mark (07725 443431) for details.
Not everyone does speed sessions but after you've been running for a while, they're about the only way you're going to improve your race times. The idea is to persuade your body to make the changes necessary to allow you to sustain a faster pace. This is done by what is called interval training. It's really just a faster paced version of the run-walk-run exercises that coaches do with novice runners. A typical session might involve a series of laps where 300m are run fast and the remaining 100m is jogged or walked for recovery. A good strategy is to build your speed steadily throughout the fast phase - moving from race pace to something faster and then sprinting for the final 100m. You can just as easily do this sort of exercise on the roads or in a park, but the track has everything nicely marked out (and it's lovely and springy, too!). Other sessions might involve sustaining a higher pace for longer, say 600m repeats, with no sprinting. For these, you get a 200m recovery.
So what about those physiological changes? Our skeletal muscles (the ones we use for running and other voluntary movements) are made up of a mixture of different types of muscle fibres. These fibres have different properties which help them to perform different jobs. Type IIb fibres (also known as fast twitch) provide explosive power but fatigue very quickly (less than a minute). They tend to burn mainly sugar and use little oxygen. This type of fibre is what you need if you are a sprinter, a jumper or a thrower. There's a second type of fast twitch fibre (IIa) and these are less extreme, working for up to 30 minutes before becoming fatigued. Middle distance athletes will have more of these. Slow twitch fibres (type I) are quite different; they use oxygen, burn mainly fat and can work for hours before becoming fatigued. One of the characteristics of trained athletes is that they have more of the appropriate type of fibre for their discipline. Having said this, couch potatoes and over-weight people have lots of fast twitch fibres, so there's more to it than that!
A common way of measuring fitness is by measuring something called VO2 max. Basically, this is a measure of how much oxygen an athletes body can extract from the air and use to produce energy. This will be influenced by lung capacity, the efficiency of the heart and the ability of those slow twitch fibres to take up and use oxygen. By repeatedly making your body work at a higher level of demand than it is used too, you improve its ability to do all of these things.