If you're a recreational runner (or a serious 7,000 to 10,000-steps-a-day walker), you want to do everything you can to avoid injury while you're enjoying the great outdoors.

Unfortunately, studies show that up to 90% of runners will be injured doing what they love. And although it's less risky, you can bet that walkers also experience twisted ankles, muscle pulls, foot problems, and even falls.

New research published in the journal Applied Sciences looked at the sleep quality of 425 runners and found that those who get less sleep or have more disturbed sleep are almost twice as likely to experience a running-related injury as those who consistently get a good night's sleep.

And in the course of any year, they had a 68% chance of becoming injured.

Disrupted or insufficient sleep causes problems because quality sleep is essential for the body to repair damaged tissue, regulate hormones, and maintain focus, letting your mind and body adapt to the physical and mental demands of training.

For help with sleep, talk to your doctor and check out The National Sleep Foundation's guidelines at www.thensf.org.

To avoid injury, I recommend taking 15 mg of gelatin one hour before a workout, along with half your daily multivitamin that contains vitamin C. That increases tendon and cartilage strength.

You can also check out "Get the Right Sneaker" at heart.org.

And to fuel your workout and recovery, look for menu ideas and information on timing your meals in my book "What to Eat When."