Injuries often plague the life of a runner. When they happen, they are painful, debilitating and frustrating. The most frustrating part of being injured is knowing that your hard-earned fitness is deteriorating while you take time off from training to heal.
In fact, this frustration can be so great that runners are often too reluctant to take time off or tempted into resuming training too soon. Consequently, injuries become worse or last longer than they should.
One way to prevent this sort of self-sabotage is to choose a favorite go-to cross-training activity that you can switch to whenever an injury makes running impossible or unwise. Having such a fallback option greatly reduces the temptation to run when you should not because it enables you to preserve fitness even when you cannot run. Obviously, there is no alternative to running that builds and maintains running-specific fitness as well as running itself, but there are some alternatives that come relatively close.
The best running alternatives are those that are most similar to running itself. Activities such as swimming and rowing are not great alternatives to running because, while they stimulate the cardiovascular system, they are arm-dominant versus leg-dominant movements. So what are the best activities for "training through" running injuries? Here are my top five:
Antigravity Treadmill Running
The Alter-G antigravity treadmill is, in my opinion, the single most important running-related invention in history. It is a normal treadmill with a tent-like enclosure attached to it. The user steps through a hole at the top of the enclosure and seals himself in around the waist, creating an airtight seal. The chamber is then pressurized, and this high-pressure zone effectively reduces the force of gravity within it. The amount of pressure is adjustable, enabling the user to run at anywhere between 20 percent and 100 percent of his actual body weight.
I have had every type of running overuse injury that exists, and I have used the Alter-G treadmill several times. Based on this experience I can say that runners can train through any injury--pain free and without setting back the healing process--on this machine. What's more, it is not an alternative to running; it is running. Therefore it is superior to every form of cross-training in terms of building and maintaining running fitness.
Case in point: The formerly often-injured runner Dathan Ritzenhein trained exclusively on an Alter-G for several weeks while nursing an IT band injury. He was only ready to return to regular outdoor running two weeks before the 2008 USA Cross-Country Championships. Nevertheless, he won the race easily. That simply would not have been possible had he been forced to resort to pool running or bicycling.
The downside of the Alter-G antigravity treadmill is that it costs $75,000. Only a handful of units are accessible for injured runners to use in high-end physical therapy facilities. It will be a while before antigravity treadmill running is a realistic option for most runners.
Steep Uphill Walking
In my opinion, the next best thing to running on an antigravity treadmill is steep uphill treadmill walking. Research has shown that the human brain uses exactly the same motor pattern to run or walk briskly on steep gradients. In other words, when you crank the treadmill incline up to 12 to 15 percent, running becomes walking and walking becomes running. Therefore, walking on a steep incline is a highly specific way to maintain running fitness. But impact forces are reduced drastically compared to running, so steep uphill walking is possible with most injuries.
Many runners don't think of walking as a good alternative to running when injured because they assume they cannot match their normal intensity. Trust me: You can. Set the incline at 12 to 15 percent, increase the belt speed to 4 mph or so, check your heart rate and you'll see.
The only limitation of steep uphill running is that, while it is a low-impact activity, it is not a non-impact activity. Thus it cannot be done pain-free with all injuries. For example, I was unable to use steep uphill walking as an alternative to running once when I had an Achilles tendon strain.
Pool running is the traditional alternative to normal running. There are two types of pool running: deep-water running, where the feet do not make contact with the bottom of the pool, and shallow-water running (usually waist high), where the feet do make contact with the bottom of the pool. I think that shallow-water running is preferable because it enables the runner to better maintain adaptations to repetitive impact, thus reducing the risk that new injuries occur after the runner returns to normal outdoor running.
As with steep uphill walking, though, because shallow pool running is a low-impact (versus a non-impact) activity, it cannot be done pain-free with all injuries.
The elliptical trainer was specifically designed to mimic the running action without impact, and thus it offers an effective way to maintain running fitness. I find it incredibly boring, though, so I only do it when I'm really desperate.
Cycling may seem less running specific than the other running alternatives discussed in this article, but a lot of noteworthy runners have used it with great success. For example, in 2004, Meb Keflezighi relied heavily on bike training to build fitness for the New York City Marathon because of injury troubles. He still managed to finish second.
Active Expert Matt Fitzgerald is the author of several books on triathlon and running, including Runner's World Performance Nutrition for Runners (Rodale, 2005) and his newest, Brain Training for Runners.