My big sports injury came as a sophomore in high school in an indoor soccer game (an off-season way of staying fresh during the Midwestern winter.) I still remember the feeling of sliding for the ball and then crashing into the wall — and another girl — with my knee.
My knee benched me for the beginning of the high-school season, a blow that hit my fragile teen psyche the hardest. I felt inferior, damaged, irrelevant.
So, when I spotted this BeWell@Stanford piece on exercising with injuries, I devoured it eagerly. Although I’m much healthier emotionally than I was as a teen, I know I want to remain active, period.
In the Q&A, Gordon Matheson, MD, PhD, a sports medicine physician, says that an injury shouldn’t kill your workout: “Fortunately, programs can be devised that work around almost any musculoskeletal condition.”
He also weighs in on the mental benefits of exercise:
Regular exercise has two main effects. One is that exercise builds greater capacity within your body; it increases bone, cartilage, muscle, joint and heart health; and helps manage weight. The other effect is something known as self-efficacy or confidence. Both are equally important. Even if you aren’t exercising vigorously, the fact that you are taking time to do something good for your body sets the mental stage for further development of your exercise goals. Once you incorporate exercise as a means of increasing the health of your daily life, you will experience an empowerment that helps to overcome the feelings of frustration and limitation.
Exercise keeps you aware of the state of your body. When you’re running, or exercising vigorously, you get some feedback if you’ve eaten too much or too little. Your body sends you a message if you’re dehydrated. You can feel bloated and stiff if you’ve had too much salt or alcohol the night before. You have trouble finishing your workout if you’ve gone without enough sleep for a number of nights. All this feedback works to help you take care of yourself and to pay attention to habits that affect your health. So it’s important to pay attention to your body if you’re not able to exercise. Don’t check out and get numb to the effects of your eating, drinking, and sleeping habits. Pay attention.
A life-long runner, I have spent my fair share of time in physical therapists’ offices seeking treatment for fitness-related injuries. Often during these visits, health-care providers assess my flexibility, deem it unsatisfactory and recommend a variety of stretches to further protect my muscles, tendons and joints from harm. But over the years, several studies have suggested that stretching may not actually help prevent injuries and the contradictory findings have left me with a lot of questions.
To get some answers I turned to Michael Fredericson, MD, who has served as the head team physician with the Stanford Sports Medicine Program since 1992. In this two-part Q&A, Fredericson discusses the role of flexibility in injury prevention and fitness performance and what the scientific evidence indicates about the effectiveness of stretching.
From a biomechanics point of view, how does flexibility influence athletic performance and help reduce the potential for injury?
It is difficult to make a vast generalization about the impact of flexibility because of the broad scope of biomechanical stresses and physical requirements throughout various athletic endeavors. For example, functional flexibility for a hurdler requires greater lengthening of the hamstring and a greater range of motion than for distance running. But in general the concern is when stretching increases a person’s flexibility beyond what is required for a specific motion.
Excessive flexibility may impair performance in sports where a high degree of flexibility is not required. For example, runners with less flexibility are actually more efficient at running. One example in a study involving 100 people, researchers evaluated participants’ flexibility with 11 different tests and then measured their efficiency while walking and running. Results showed, participants who were the most flexible expended 10 to 12 percent more energy to move at the same speed as compared with those that were the least flexible.
In everyday life, individuals maintain flexibility in a specific joint by using it. As we age, decreased activity and lack of use of a joint leads to reduced flexibility. The same is true for athletes. Participating in the sport itself provides the stimulus required to maintain their necessary range of motion. So, in many sports it is more desirable to achieve the required range of motion through specific actions that simulate the movements of the sport, rather than with prolonged stretching. Intense stretching could result in the range of motion exceeding what is needed for athletes to compete and consequently diminishing their performance.
There is an ongoing debate on if static stretching, where you hold a position for 20-30 seconds, is beneficial. How effective is this style of stretching?
Static stretching can increase muscle length but this doesn’t necessarily benefit all athletes equally. While some athletes such as gymnasts and swimmers may need to gain flexibility, being excessively flexible doesn’t benefit distance runners. Consider the standard hamstring stretch. Stretching your hamstring teaches the muscle to relax when the knee is fully extended. However, this doesn’t benefit runners. Instead, runners need to have their hamstrings stiff and activated when the knees are extended. Additionally, studies such as a recent USA Track and Field study (.pdf), have found that static stretching seems to have little benefit in terms of injury prevention, particularly against the overuse injuries common in running.
Another thing to keep in mind is that prolonged stretching, greater than 60 seconds, prior to athletic activity can reduce maximum force production with the loss of voluntary strength and muscular power. This effect can last up to one hour after stretching. For this reason, intense stretching is not typically recommended prior to competition. However many athletes, especially dancers and others participating in activities that require more than average flexibility, may still find shorter bouts of static stretching beneficial.
Salar Deldar, a third-year medical resident at Stanford, contributed information to this entry. The Q&A continues tomorrow with a discussion about the effectiveness of stretching before a workout vs. afterwards and the role of genetics in flexibility.
My friends know they are going to get an evidence-based read on medical practices when they turn to me for advice. Not all of them enjoy the eye rolls that involuntarily occur when I hear what they are considering, like when a friend asked me about the benefits of whole body cryotherapy.
Cryotherapy is the practice of subjecting tissue or lesions in tissue to very cold temperatures in an effort to kill something that is considered unhealthy. It can also mean the application of ice packs to reduce swelling or pain on a part of the body.
Icing an injury: There’s little good evidence for it. Photo: iStockBut whole body cryotherapy exposes the body for a couple of minutes to vapor that has been supercooled to somewhere between minus 94 and minus 148 degrees Celcius. It was once confined mostly to elite athletes, but now centres have cropped up across the country asserting that the practice can lead to any number of health benefits.
There is not much evidence, however, to back this up. A 2015 Cochrane systematic review looked at studies assessing the benefits and harms of whole body cryotherapy in preventing and treating exercise-induced muscle soreness in adults. The authors found four laboratory-based randomised controlled trials that included 64 young adults (average age 23), 60 of whom were male. All of the studies were judged to have some problems with design features, and overall, they found insufficient evidence to support the use of whole body cryotherapy for muscle soreness. Moreover, there was almost no evidence supporting its use for women or for the middle-aged and older people.
When we get into specific treatments, the evidence is even more scant. A recent two-week study (which doesn’t appear to have been randomised or blinded) found whole body cryotherapy to be similar to traditional rehabilitation in improving outcomes for 44 patients with rheumatoid arthritis. A case control study of 24 patients with multiple sclerosis found that those who received whole body cryotherapy had improved functional status and reduced feelings of fatigue. In a small randomised controlled trial lasting eight weeks, 12 patients with restless leg syndrome seemed to see improvements in symptoms and quality of life.
These were all small studies, involving few patients, over short periods of time, with minimal overall changes. Given the likelihood of publication bias here (positive results are more likely to be published than negative ones), it’s hard to make sweeping recommendations based on these findings.
Because so little data is available, the Food and Drug Administration has not certified cryotherapy chambers to treat anything, including muscle pain or inflammation. For this reason, they cannot be marketed to treat diseases.
That doesn’t stop all kinds of other assertions from centres that offer whole body cryotherapy. Some say it can help people lose weight. Others argue that it can help slow ageing and make you look younger. There are even those who maintain that it can make a difference in your mental health. None of these claims have been the subject of well-designed studies.
Most of the research on whole body cryotherapy doesn’t focus on disability or disease but on athletic performance. In 2013, a meta-analysis published on 21 randomised controlled trials showed no significant benefit to endurance, strength or the ability to jump. There was some benefit to sprint performance, but even this seems to be the result of one outlying study.
This hasn’t stopped these athletes from continuing to use cryotherapy. But as I’ve discussed before, many athletes are willing to spend money and try therapies with little proof of potential gain.
The bad news is that even the use of ice to take care of localised injuries isn’t nearly as well supported as you might imagine. A systematic review published in The Journal of Athletic Training in 2012 gathered evidence from studies testing “rest, ice, compression and elevation” therapies. They found limited evidence to support the use of ice in the treatment of ankle sprains.
A 2004 systematic review looking at the use of ice for a variety of soft-tissue injuries found that “many more high-quality trials are needed to provide evidence-based guidelines in the treatment of acute soft-tissue injuries.”
Of course, applying an ice pack has few potential harms and almost no cost. If people find benefit from that, I’m not going to argue that they should stop. The potential downsides of whole body cryotherapy are much more significant.
Whole body cryotherapy is also inherently dangerous, which is why it should never be done alone. In 2015, an employee using a cryotherapy chamber after hours unaccompanied was found dead inside. Freezing your body can also result in hypothermia or frostbite, adding to the necessity that the procedure be monitored closely.
Whole body cryotherapy isn’t cheap, either. Sessions can run between $50 and $100, and no insurance plans I know of will help you cover those bills. Given all of this, and the utter lack of proven benefits, when my friend asked about it, an eye roll was probably the appropriate response.