A 50-something goes for a daily jog and is jolted by back pain, or finds his weekly tennis game suddenly hampered by an arthritic knee. Orthopedic surgeons are seeing a wave of exercise-related injuries among baby boomers and have dubbed the phenomenon "boomeritis."

True, baby boomers, now in their 50s and 60s, are fitter and more athletic longer into their lives, compared with their parents' generation. They are running marathons, hitting the slopes, playing hockey, cycling the country, and more.

While staying active promotes health, at age 50 and older the body is less forgiving. Injuries can occur when people push beyond the body's capability. Typical problems include tendonitis, bursitis, stress fractures and tendon tears, such as rotator cuff injuries.

Doctors writing in the Mayo Clinic Women's HealthSource offers these tips to help avoid boomeritis:

Ask your doctor first

A doctor can offer advice when a person is considering a new sport or activity. In general, it's wise to start slowly and increase gradually.

Warm up

A warm-up prepares a body for activity by getting the blood flowing, raising muscle temperature and increasing the heart rate. Moderate activities, such as walking on a treadmill or cycling in a low gear, are good warm-ups. Cold muscles are more prone to injury.

Stretch

Past age 40, joints, tissues and muscles may not be as flexible as they once were. Stretching after exercise, when muscles are warm, can help prevent injury and may improve performance.

Cross-train

Alternating different types of activities works various muscle groups, which helps muscles adapt to new activities. A balanced fitness program should include cardio work, strength training and flexibility exercises, such as yoga, and exercises such as Pilates that target the core muscles.

Be consistent

Compressing hours of heavy activity into the weekend sets the stage for injury. A better approach is aiming for 30 minutes or more of moderate exercise daily.

Listen to your body

Boomers may not be able to tolerate the same sports or participate as long or as intensely as they could when they were younger. Significant stiffness or strain indicates too much intensity.

Don't overdo it

A rest period or a rest day after an intense workout can help avoid injury. A good rule is to increase activity by no more than 10 percent each week, for example, adding one mile a week to reach a 10-mile-per-week walking regimen.