You've faithfully jogged three times a week for years, and think you're in pretty good shape. But when a less athletic friend suggests you go inline skating, you're shocked to discover you can't keep up.
Perhaps you've mastered the elliptical machine, and regularly work out on it for 45 minutes at a stretch. But one day you bend over to pick up your 4-year-old, and you end up with a back injury that lasts for weeks.
Or maybe you're a power weight lifter, the top bench presser at the gym. But when your son's new puppy takes off around the block, you get winded trying to catch him -- and the puppy isn't even breathing hard.
All of these scenarios show what can happen when you think fitness means mastering a single sport or activity.
"When you only do one fitness activity -- like running or weight lifting, for example -- and you only work on the muscles involved in that sport, you may discover that you are far less fit than you think," says Todd Schlifstein, DO, a sports medicine rehabilitation doctor at New York University Medical Center's Rusk Institute.
Using just one set of muscles repeatedly can also increase your risk of repetitive injury, Schlifstein warns.
"The harder you train your body for just one activity, the more stress you put on all the muscles and bones involved in that one activity, so the more you do and the better you get, the more you risk overuse -- and the greater your risk of injury," says Schlifstein.
So what's the answer? Athletic trainers and personal coaches agree it's cross training -- essentially, alternating your workout routines in a way that will increase your performance and overall fitness without stressing your body to the max.
For a single-sport athlete, cross training can mean anything outside the athlete's primary sport, while for the fitness enthusiast, it means using many different activities to ensure total fitness, says James Herrera, MS, CSCS, director of coaching with Carmichael Training Systems and Trainright.com in Colorado Springs, Colo.
How Cross Training Can Help
While professional athletic trainers once believed it was most important to work on those muscles directly related to a particular sport or activity, experts now say cross training is a much better approach. All sorts of professional athletes, from ball players to golfers, tennis players to swimmers, make cross training part of their regimes.
Cross training is also making its way into the average person's fitness routine, with more and more "weekend workout warriors" discovering its benefits.
But exactly what can it do for you?
Professional athletic trainer Jim Thornton, MA, ATC, sums it up this way: "Cross training takes into consideration the fact that many muscles in different parts of the body contribute to a single activity. So to get the most out of any activity, and to do it safely, you must pay attention to all the muscles in your body that are involved, not just the ones directly related to that activity."
For example, while a runner needs to build strong leg muscles, he or she must also pay attention to the muscles that control pelvic movement, core strength -- even the upper body. "All these areas are utilized when you run," says Thornton, director of athletic training services at Clarion University of Pennsylvania and a member of the board of directors of the National Athletic Trainers Association.
But that's not all. Experts say cross training can also help us with the tasks of our daily lives.
"Implementing a variety of activity into your routines almost certainly guarantees that you will be much more functionally active … and that you can complete day-to-day tasks with much more ease," says Herrera.
Climbing stairs, working around the house or yard, or taking the dogs for a walk takes much less effort when you're "functionally fit," he says. It's also easier to avoid injuries related to those everyday activities.
"You're much less likely to injure yourself bending down to pick a child or heavy box off the floor," says Herrera.
What Cross Training Involves
For people devoted to a particular sport or fitness activity, there are specific activities that make up an ideal cross training routine.
For example, if running has been your only activity, your "prescription" for overall better fitness would include strengthening exercises for the pelvis and hips, as well as weight workouts to build the upper body, Thornton says.
If you've been doing only weight lifting regimens, you'd be well served by adding a cardio workout -- like running on the treadmill -- to your regimen, he says.
But for people who are simply looking get the most out of their workout time, experts say, cross training doesn't require specific exercises. In fact, as long as you create variation in your activity, you're cross training!
"The point here is to vary activities between aerobic conditioning, strength training, endurance, and balance -- and you need to vary the workouts that emphasize each one of those areas," says Herrera.
For optimal success, he says, plan two to three days of flexibility and strength training, and three to five days of aerobic focus. But don't worry if you don't have that much time to devote to exercise.
"The most important thing is to make sure fitness is a priority in your life," says Herrera. "So if you're currently exercising twice a week, then simply finding time for one more workout during that week will help you burn more fat and make more progress."
In fact, experts say, you don't even have to do a specific workout to get the effects of crossing training if you live a varied and physically active life.
"Keep in mind, variety is the spice of life, so enjoying rock climbing, Rollerblading, cycling, hiking, jogging, or skiing with friends, which are also excellent ways to stay socially active and keep the body fit,' says Herrera.
How Cross Training Is Done
So what's the best way to achieve cross training?
It could mean doing two or more different types of exercises during a single workout session. For example, Herrera says, "a yoga or Pilates class will incorporate the components of strength development and flexibility in the same workout session, while an indoor cycling class will develop the musculature of the legs while improving aerobic capacity."
It can also mean performing a single type of workout during each session, but varying what you do from session to session, Schlifstein says.
"You can concentrate on cardio during one session, strength training and balance in another, and flexibility in still another," he tells WebMD. "Then just keep mixing up the combinations so your body has variety and you don't get bored with your routine."
Because variation is key to cross training, it's easy to confuse it with the rotating workouts involved in "circuit training" (in which participants move right from one exercise to another, like jogging for a few minutes in between different weight training exercises). But experts say the two aren't necessarily the same.
"Generally speaking, circuit training is just doing one exercise after another, but that doesn't always ensure that the routine is incorporating strength training, cardio, flexibility and balance," says Schlifstein.
For true cross training, Herrera says, you must "utilize many activities to ensure complete fitness gains."
Putting Cross Training to Work
Still not sure where to begin? We used advice from our experts, along with data from the journal The Physician and Sportsmedicine, to create the following sample cross-training routine.
If you have lots of time for fitness, you can do one session per day. If you normally work out only twice weekly, you can just do two of the sessions per week. Remember, however, to check with your doctor before you begin cross training -- even if you've been exercising regularly.
Session 1: Walk briskly for about 20 minutes, adding hand weights to increase the impact. Also do stretching for 5-10 minutes, then lift weights or use resistance bands for upper body strength for 20-30 minutes.
Session 2: Jog at a steady pace for 20 minutes; stretch for 5-10 minutes; do weight training or any other exercise that builds lower body strength for 30 minutes.
Session 3: Swim for 20-30 minutes; then do yoga, Pilates, dance, or another activity that enhances balance and flexibility, for 20-30 minutes.
Session 4: Use an exercise bike, rowing machine, or cross-country skiing machine for 20-30 minutes; stretch for 10 minutes.
Session 5: Walk briskly for 20 minutes; then train both your upper and lower body using weights or resistance bands for 20 minutes.
Session 6: Jog at a varied pace for 30 minutes; stretch for 10 minutes.
Session 7: Walk at a comfortable pace for 30-45 minutes; then do yoga or Pilates for 20-30 minutes.