For millions of Americans trying to lose weight and get in better physical shape, many of the hot new exercise trends like spinning and Tae Bo are just the answer. But for some, these heart-pumping, high impact exercises can result in injuries instead of better health.

“Everyone is looking for an exercise program that’s fun. Let’s face it, if your exercise routine is boring, you won’t do it regularly,” reports Dr. Brian A. Casazza, clinical assistant professor of physical medicine and rehabilitation, University of Virginia School of Medicine. “The key is finding an inspiring workout that doesn’t compromise your health.”

We frequently hear the disclaimer to “consult your doctor before beginning any exercise program” but few people do. One study estimates that in 1998 over one million people aged 35-54 were injured while exercising. That had a healthcare cost of $18.7 billion. These injuries might have been prevented had the participants known more about their exercise program and their physical limitations.

“PM&R physicians specialize in prescribing exercise to people who need rehabilitation as well as healthy individuals beginning a new exercise program,” explains Dr. Julie K. Silver, an instructor at the Harvard School of Medicine, department of physical medicine and rehabilitation. “You shouldn’t fear exercising if you’re middle-aged. Just be aware of the requirements of that exercise and how it impacts you.”

To better assess which exercise trends are best and safest for you, Casazza and Silver critiqued some of today’s hot new exercise programs as well as a few traditional ones.

Spinning

According to both Silver and Casazza, this heart-pounding bicycling workout is a great cardiovascular exercise. “People like spinning, because in a class setting it can also be a social activity,” shares Silver. “It’s a great cross training and low impact exercise.”

On the cautionary side, spinning classes are strenuous exercise. People may unwittingly pressure themselves to do too much too soon. Silver emphasizes that it’s okay to stop in the middle of any workout if you’re feeling fatigued. “This is strenuous, aerobic exercise. People need to remember to gradually work up to the maximum workout levels or they risk injury,” adds Casazza. “Not only is this important for older individuals but also people with knee problems, especially kneecap pain. They should check with their doctors, because the high speed cycling can aggravate these conditions.”

And with any bicycling activity, Casazza and Silver point out that remaining seated with your back in a flexed position for 30 or more minutes can cause back pain. Casazza recommends keeping your back straight and doing proper warm up and cool down stretching exercises.

Tae Bo / Cardio Kickboxing

Silver and Casazza applaud this exercise because it’s fun and incorporates multiple muscle groups. Because people enjoy how they feel when they do cardio kickboxing such as Tae Bo, they’ll be more likely to stick with the exercise. “It’s a great stress reliever too,” adds Silver.

The main area of concern with Tae Bo is the possibility for hyperextension when punching and especially when kicking. Proper instruction is key to preventing over-extension.

“Adults are not always very flexible in their hips and gluteus (buttock muscles). This can adversely affect their form when kicking,” illustrates Casazza. “They may extend and arch their backs, which can cause injuries.”

To avoid kicking injuries, Silver recommends that Tae Bo participants maintain good hamstring and hip flexibility. She also warns that this program may not be suited for people with arthritis or joint problems.

Yoga

Yoga may well be one of the hottest exercise trends in America. It has received an overwhelmingly positive reaction from participants, because it increases flexibility, promotes proper breathing, and is a mental as well as physical challenge.

Difficulties can arise however when participants attempt to stretch too far. “Yoga is a flexibility intensive exercise. It’s also not a contest,” warns Casazza. “You need to warm up first and really be intelligent about how far you can stretch. Otherwise, you can injure your muscles.”

According to Silver, you can also injure yourself if you’re too good at yoga. “It’s possible to be hyper-flexible,” explains Silver. “This can create instability by over-increasing the range of motion in joints. Remember—the job of tendons, ligaments, and muscles is to stabilize the joint and not let it extend too far or become too loose.”

Walking

Walking wins points as an excellent exercise, particularly for older adults. Swinging your arms and walking at a brisk pace to elevate your heart rate are often recommended. However, recent research indicates that the amount of time you walk may be just as important for cardiovascular benefits.

“Walking is great, because it is a weight bearing exercise with very low impact,” says Silver. “It’s easy, convenient, and only requires good walking shoes with plenty of support.” Don’t forget that in inclement weather or congested urban areas, many malls open early for walkers.

Final Tips

Most important for all exercises, Casazza advises doing a five-minute “warm up” first by gently performing your selected exercise. You should stretch after this warm up, because stretching cold muscles can cause injury. After your workout, stretch again.

Silver also reminds fatigued athletes, “Just because you’ve paid for an exercise class or gym membership is no reason to continue exercising and risk injury,” advises Silver. “You’re not a wimp if you decide to avoid injury by stopping or resting.”