When I go to the gym or see people exercising outside, most of them are moving in one direction-- forward. Think about it- walking, running, biking, using the elliptical or stairmaster are all forward motion. That is not the only way we move our bodies in real life. Every day, we move forward, backward, sideways, twist, bend, go up and down. We push and pull, squat and lunge. This is how you should exercise. Train your body with real life movements. This is called functional training.
Many people get injured when their bodies aren't prepared for the movements that I just talked about. Most knee and ankle injuries occur in non-athletes simply because somebody twisted wrong or stepped down incorrectly and their joints weren't ready for it because the muscles protecting the joints were weak and untrained. Many people have back pain due to a weak core....crunching and sit ups in one plane of motion does not make a strong core. You can also have back pain due to gluteals that are "sleeping." Their not doing their job due to undertraining and so the low back takes over.
When you are preparing your exercise routine, remember to include movements on different planes in different directions. For example, when you take a walk, include some lunges or stairs to get that up/down plane. Walk sideways or backwards up and down the stairs. Twist and bend while holding a weight. (Make sure you hold your belly button in and squeeze your gluteals to brace that core.) A "woodchop" is a great exercise for these movements; look it up on YouTube to get a visual. Include jumping movements in your workout, but be cautious of how you land and make sure your knees don't come past your toes and are in line with your middle toes to prevent injury. When you lift weights, make sure you even out how many push exercises you have versus pull. Choose some weight training exercises that involve standing on one foot or in a split stance. Real life doesn't involve standing with both feet together at all times, so you need to train accordingly. And for heaven's sake, stand up when you work out as much as possible. It drives me crazy to see people sit at one machine, then the next machine, and the next, etc. We sit enough as it is.
If you need guidance on ideas, hire a trainer (like me). Read some fitness books or come up with your own ideas. A really great series of books on this topic with workouts included is the New Rules of Lifting series by Lou Schuler and Alwyn Cosgrove. Rachel Cosgrove's books are another resource for fantastic fitness programs.
Move forward in your journey and toward your fitness and health goals, but go every which way that your body was intended to move.
