It's February and hopefully you're proud of yourself for sticking to the resolution you made on Jan. 1 to start exercising regularly. You've been hitting the gym three times a week, doing 30 minutes on the treadmill and 40 minutes of weight training and stretching. It's a wonderful feeling once you get going on a consistent workout schedule, but just as pushing yourself too hard can lead to injury, so can engaging in the same exercise over and over without varying your routine. This can put you at risk for overuse injuries and muscle imbalances, not to mention it's so boring that you won't be motivated to stick with it.

So mix things up and cross train. Instead of always running on the treadmill, alternate between swimming, using the elliptical, or taking a spinning class. If you're always using dumbbells to strength train, try using weight machines, kettlebells, or resistance bands. Varying your routine will challenge and work all your muscle groups, so not only will you have more fun, but your entire body will get stronger and more fit.

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