Posted on Oct 24, 2019, 4 p.m.
Article courtesy of Dr. Nicholas DiNubile, Vice President of the A4M, an orthopedic surgeon specializing in sports medicine, best selling author, keynote speaker, and one of our medical editors who is dedicated to keeping you healthy in body, mind and spirit.
Just because an exercise is low impact does not necessarily mean it is low intensity, low effort, or low rewards. Low impact can mean more fun, more engaging, and getting results without sacrificing your joints.
Sometimes people train too hard, or push themselves too far which can result in damage or injury. Take for example a runner who had tried to compete in a 26.2 mile run but had failed twice due to pain from uterine prolapse until she underwent a hysterectomy and surgery to repair the damages. After recovery and feeling fine she thought to give it another shot and began to train hard which was tough and so was the race; at mile 13 she began to feel pain and pressure in her abdomen, but still managed to cross the finish line and complete her lifelong dream.
In the days after the lower abdominal pressure did not stop, she had pushed her body too far. She was lucky to have no permanent damage to the surgical repairs from the previous year but was told going forward she was to only do low impact exercises with no running, no lifting heavy weights, and nothing strenuous. This was a setback to a person who loved running and how strong it made her feel who could now not do running of any kind, even at a slow pace for a short distances, so she stopped doing everything.
Unfortunately this experience is not unique, as many people are prescribed low impact exercise routines for a variety of reasons, it may be temporary or permanent due to injury, rehabilitation, recovery after surgery, or prevention of joint related pain, especially with age.
“That’s because stress and impact can cause damage to joint cushions, tendons, and muscles, especially if your musculoskeletal frame is not as durable or limber,” says orthopedic surgeon Nicholas DiNubile, MD, author of FrameWork: Your 7-Step Program for Healthy Muscles, Bones, and Joints.
Low impact is a blanket phrase and a loaded term that is often thought of as being overly restrictive and inferior to more rigorous regimens. Many who are instructed to stick to low impact training tend to opt out of exercise completely, but Dr. DiNubile and other experts suggest that this can lead to further immobility, injury and loss of self confidence.
When properly implemented low impact exercises include opportunities to push your body, achieve goals, improve health, have fun, and feel good about yourself; these forms of exercise are not a step down from high impact workouts and they are still challenging. Benefits from low impact exercises are not limited to those who have injuries or are older, everyone can benefit from them to improve fitness by incorporating low impact routines.
Dr. DiNubile explains that the difference between high impact and low impact is not the amount of effort or value it adds to fitness, rather it describes the type of muscle contraction elicited and the forces exerted on your body.
Muscles operate much like light bulbs being switched on or off to contract in 3 distinct ways:
- Concentric contractions occur when you shorten a muscle under load; this is when muscles are exerting force.
- Eccentric contractions occur when a muscle is lengthened under tension; this is when muscles are absorbing force.
- Isometric contractions occur when muscles are tightened without shortening or lengthened.
Bicep curls can help to illustrate the difference between the contraction phase. The concentric phase occurs as the dumbbell is curled up from open elbow to closed elbow the biceps muscle shortens. The eccentric phase occurs when you lower the weight and the muscle extends. The isometric phase occurs when you pause at any point in the movement between the completely opened and completely closed elbow. Though an oversimplified explanation while the biceps muscle shortens, lengthens, and holds other muscles in the arm and elsewhere are also contracting; controlled biceps curls provides a balance outlook at the types of contractions, but some activities emphasize certain phases over others.
Running and plyometric work like box jumps emphasizes eccentric contractions, the muscles are primarily absorbing force, and the amplification of force is incredibly powerful, says Dr. DiNubile. While running with every step taken the knee absorbs 5-7 pounds of impact for every pound you weigh; for a 150 pound person that is up to 1,050 pounds of force on the knees. Healthy knees can withstand the force and recover from it, and in the process the tissues in and around the joint can grow stronger.
For those with knees that are compromised from overuse, injury, aging, fatigue, being sedentary, or the wrong footwear it may be more difficult or even impossible to deal with the forces resulting from the eccentric phase landing, lowering, and decelerating. Impact can reach farther than the muscles bearing the brunt of the force: joints, bones, connective tissues, internal organs, and muscles that aren’t primarily used in the activity can be affected by the force. This is why lower impact training comes into play.
Activities that emphasize concentric contractions include movements where the muscles are primarily producing forces, exercises that involve holding a position emphasize isometric muscle action, engaging muscles while reducing eccentric force. These movements offer valuable option to anyone with restrictions by still taxing the muscles and cardiovascular system while being easier on joints and internal organs.
Intensity and impact are not the same thing, you can perform a high impact workout without engaging in a high intensity routine, and the reverse is also true. Rowing, swimming, cycling, yoga, and strength training all challenge muscles and the cardiovascular system with minimal impact on the joints. Incorporating low impact moves into a higher impact regimen can act as an insurance policy, and by mixing muscle contraction types helps to ward off orthopedic problems later on.
“Sometimes when I’m operating on someone’s knee, I’ll see significant areas of wear that weren’t bothering them,” DiNubile explains. “After the operation, I’ll say to them, ‘You have 50,000 miles left on your knee. Do you want to use it all up this year, or do you want it to last a lifetime?’”
Running is free, convenient and effective, as such, many consider it to be one of the ultimate workouts. However, it is very high impact, unless you are already fit, adequately stable throughout the body, and without injury the forces incurred while running may put you out of commission before gaining any cardio rewards.
“People say, ‘I’m going to run to get in shape,’” DiNubile notes. “It makes more sense to get in shape before you run.”
There are many options for low impact such as indoor cycling, yoga, dancing, Zumba, swimming and pool based workouts. Water aerobics are the lowest impact options as they can reduce the impact to virtually zero to provide mild compression, joint support, and resistance in all directions. By turning up the intensity you can turn almost any low impact exercise into a cardio workout, such as lifting lighter weights with fewer breaks.
Strength training can limit impact and help to make the body more resilient to higher impact in the long term. The controlled context of a lifting routine can help to improve bone density, spur muscle growth, and engrain healthy movement patterns by practicing eccentric movements slowly and deliberately.
Yoga, Tai Chi, natural movements, and primal exercise philosophies favor concentric and isometric contraction by improving the body’s ability to work at its best while inherently limiting impact. These ancestral movements emphasize relaxation and balance while helping to build mobility, flexibility, stability, balance, and body awareness. They can also be modified to promote cardio and strength without increasing impact. The movements should be challenging but not forced, the quality movement can be very therapeutic.
Very often intensity is confused with impact, but they are not synonymous; high intensity workouts can be low impact, and vise versa. Impact is the amount of force exerted on the body which is measured in terms of muscle contractions. Low impact minimizes absorption of forces to help you get fit and stay fit over the long haul or recovering. Intensity is how much effort a workout requires. Low intensity workouts are performed at a steady state and typically allow you to have a conversation, whereas high intensity workouts push you to move faster and breathe heavier making a conversation very difficult.
For those that have to stick to low impact exercises, there are many options to still provide a high intensity workout while being gentler on your body. Rather than focusing on the sense of loss due to limited running and jumping try to focus on the new things you can learn and the new ways you can grow. Low impact exercises still mean that there is a lot of fitness waiting to be gained and utilized to move forward in a healthy lifestyle.
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This article is not intended to provide medical diagnosis, advice, treatment, or endorsement.