Runners are always searching for ways to improve their economy, which is simply their oxygen 'cost' of moving along at a particular pace ('cost' is actually the rate of oxygen utilization which corresponds with a specific velocity). As this oxygen cost decreases, a particular, desirable speed can be sustained at a smaller fraction of V02max, one's maximal possible rate of using oxygen. This is advantageous, because perceived effort (how the pace FEELS to you) is tightly related to how close you are to V02max; the closer you are, the harder the pace feels. Becoming more economical makes training and racing velocities feel easier to sustain.

Improving your economy is a little like having a monthly income of £1000 and seeing your rent fall from 400 to 300 quid a month, which increases your financial comfort level and allows you to buy more things that you want. As the rate of oxygen use declines, runners can 'buy higher speeds without getting too close to their maximal rate of oxygen utilization - V02max.

What do runners have to do to improve economy? Hill training can definitely do the trick, and researchers have long wondered whether strength training might also enhance economy. In theory, the idea is reasonable: if leg muscle cells are made stronger through resistance training, fewer cells should need to contract during the act of running, lowering the gobbling up of oxygen during both workouts and races and making running feel easier. Now, new research carried out at the University of New Hampshire demonstrates that strength training can in fact make runners more economical.

At New Hampshire, 12 trained, female distance runners (average age 30) were divided into two equal groups, (1) an endurance and strength training group (ES) and (2) an endurance training group (E). Both groups ran at least four days per week for at least 20 weekly miles, but the ES group also performed upper- and lower-body resistance training three days per week.

After just 10 weeks, ES group member s were 24-per cent stronger in their upper bodies and 34 per cent more powerful in their legs. This augmented power translated into about a 45 per cent improvement in running economy at a range of different running speeds (a 4-per cent improvement of economy can produce about a 3-4 per cent speed-up in 10-K times). The E-group members, who simply carried out their normal running training, failed to improve running economy at all.

The programme of strength training had no impact at all on V02max, but that wasn't surprising, since V02max gains generally come from either cardiac improvements or increases in the ability of muscles to extract oxygen from the blood. Resistance training is not the most efficient way to produce either of those V02max-enhancing changes, but the gain in economy associated with strength training is good enough reason for runners to spend some time playing 'the iron game'.

('Strength Training in Female Distance Runners: Impact on Running Economy and Blood Lactate Accumulation,' Master's Thesis of Ronald E. Johnson, M.S., University of New Hampshire, 1994)