Despite popular belief, running a ton of miles is not the only way to make it to the start line of a marathon. Various people have proven that a serious cross training regimen can help get you in great shape without putting as much pressure on your joints as running does. Below we will give you some tips for biking, swimming, and elipticaling.
Similar to running, biking focuses on the leg muscles and can help prepare you for the 26.2 mile distance. Try to keep the following in mind if you're going to use biking as a major component in your training:
Swimming is the ultimate "no impact" activity. While swimming laps is certainly great for increasing anaerobic strength, aqua jogging may be the best way to utilize swimming as a cross training activity for running. When aqua jogging, go into deep water where your feet can't touch the ground and move your legs and arms in the same motion you would for running. If needed, you can use a floatation belt to stay above the water, but many runners find that aqua jogging without a belt has all the benefits of running without the costly impact on your legs.
While biking is great for strengthening your legs, it doesn't exactly mimic the same motions as running. Thus, you could also try out the eliptical which more closely relates to running in terms of motion. Similar to biking, though, make sure you try different inclines in order to mimic the hills you may encounter in a marathon.