Cycling vs Running

You want to get fit fast
Cycling: Just like at school, you develop staying power on the local bike. "Cycling's low impact, so you keep going longer," says Matt Parker, coach at British Cycling. "It's sustained stamina training."
Running: It won't max stamina as fast for one reason: it hurts. "Running leads to muscle soreness and damage," says Nick Grantham of the English Institute of Sport. "It's no wonder cyclists keep going for longer."
>> Winner: Cycling

You want to build muscle
Cycling: "Cycling power is generated by glutes, quads and hamstrings," says Parker. "So you'll see gains in leg bulk." Hit the dumb-bells, too, to avoid your top-half looking like a stick drawing.
Running: "You can't bulk up by running, even with hill training," says Grantham. In fact, you'd have to be mad to try. Running spreads strain throughout your body.
Ever see Schwarzenegger running? Exactly.
>> Winner: Cycling

You want to stay off crutches
Cycling: Injuries per 1000 hours: 6
You'll crash only once every 900,000 miles. "Ensure your legs can't fully straighten to minimise injuries," says Parker. Sticking to this rule off the bike is amusing but unnecessary.
Running: Injuries per 1000 hours: 11
"Shockwaves compress your vertebrae," says Harley Street podiatrist Simon Costain. Marathon runners shrink by a centimetre during a race. Temporary. But not good – especially if you're Danny DeVito.
>> Winner: Cycling