As reported on BBC 1's The One Show on 15th Sept (the item is at 17' 55") new research from Professor Rami Abboud at Dundee University has shown that a change in running style will help reduce stress injuries and wear on your joints.
Modern running trainers, with their shock absorbent heels, have encouraged a running style which involves landing heavily on the heel first followed by the toes. Running in this way has a damaging effect on the joints as the impact of the landing is transmitted directly up the leg through the ankle, knee, hip and spine. Professor Abboud's research shows that if you land on your toes, there will be almost no impact on the heel and directly up the leg. The impact will be absorbed by the calf muscle which, acting as a spring, then releases the absorbed energy later in the step and helps forward motion.
So, given that running is a great way to increase fitness and stamina, it makes a great deal of sense to act on the latest research in order to reduce what have always been seen as its negative effects - and perhaps give yourself great looking calf muscles into the bargain.