When developing a workout program, one thing to consider is whether your program should include low-impact or high-impact exercises. To understand the differences between the two, Systemwide spoke with Dr. Randy Bonnette, chair of the Texas A&M University-Corpus Christi’s Department of Kinesiology.
First of all, what is meant by “high impact” and “low
impact”?
Basically, moving when one foot is always in contact with the ground (e.g.
walking) is considered low impact. When you are in flight, meaning both feet
are in the air, it is high. For example, even in a step class with the steps
stacked very high, if one foot is in contact with the ground until the other
foot touches the top step and then the back foot is raised, it is a low-impact
event. However, if the instructor has the students jumping or even running
in a circle around the room, it is high-impact.
High-impact exercises include running, leaping, pliometrics, step aerobics where you bound off of the steps, and jumping rope. Low-impact exercises include walking, step aerobics with no flight, treadmill with no flight, and roller blading. There is also no-impact cardio, such as swimming, Stairmaster, cycling, elliptical machines and cross-country skiing.
What are the benefits of each?
No different than any other exercise. It depends on the duration, intensity,
and how many times a week you do it.
What are the drawbacks of each?
High-impact exercises present possible joint problems, mostly in the ankle,
knee and hip, but also all the way up the spine. Here’s the deal: Gravity
makes us fall at 32 feet per second, every second. Therefore, even in light
running, where you are airborne for a short time, the foot pounds of pressure
when your foot hits the ground (including forward momentum as well as gravity)
goes up and may be over twice what it is with walking. That means that, while
running, a 120-pound woman may land on one foot with about 240 foot pounds
of pressure on that one ankle, knee and hip joint.
My wife, a fitness and dance instructor, likes to say your heart doesn't know if your body is in the air, on land or in water. It just knows it is being called to supply more blood. So if working your heart is good, why do something that has the potential to hurt your joints? Therefore, if you have to hit the road and need a good sweat to feel good about yourself, walk really fast. You'll get the same results as running and none of the high-impact problems.
Without question, the harder you work out the greater the benefits in terms of muscle, cardiovascular system and even bone density! Bone density also improves joint stability and integrity. But, over time, it will have its negative effects. Moderation is the key.
What factors should people consider before taking part in
either type of workout?
Basically, people should consider the same things they would with any type
of workout. What does your doctor approve or recommend if you have any health
risks, such as diabetes, severe weight problem or cardiac or respiratory issues?
What do you like to do? What do you have available to you? What can your body
withstand? Obviously, an obese person should use no- or low-impact cardio.
This information is provided as a service by the Texas A&M University-Corpus Christi’s Department of Kinesiology. If you have questions or would like more information, talk to your physician.
H.E.A.D.s Up is a monthly column that features articles on a wide array of Health, Exercise And Diet issues. Information for these articles is provided by health and wellness professionals from throughout the A&M System. If you have questions or story ideas for this column, email Ruth McMullan.