Ice versus light for performance athletic performance and muscle recovery. Below is information from the Journal of Sport Rehabilitation. It was published in 2019, and the title of this review is "The Effectiveness of Photobiomodulation Therapy Versus Cryotherapy for Skeletal Muscle Recovery: a Critically Appraised Topic." So, specifically, they're talking about light and light therapy versus ice or cold therapy. If you've played any kind of sports in the last 40 years, you know that coaches and trainers and a lot of doctors will tell you that you need to use ice after you have had a hard practice or intense exercise session. They'll say it will bring your soreness down and help you recover faster. Some will say that if you have an acute injury, you need to get ice on there. You need to ice it all the time. A lot of times doctors will even coach you on using ice for chronic injuries.
But what does the science say? We've been doing things like this for years, but what does the science say about what really happens when you use ice or cryotherapy?
First, let's look at what happens in exercise in general. This study says after completing an intense exercise (especially one that's unfamiliar) an athlete experiences physiological stress within the effected muscle. Muscle stress causes energy substrate depletions, such as glycogen and ATP, mechanical muscle damage, oxidative stress, inflammation, and neuromuscular fatigue. Muscle fibers are also damaged as a result from the exercise—especially from prolonged or straight exercise. And, if it's a new exercise, those consequences are magnified that much more. They say, "as a response to this exercise-induced muscle damage, an inflammatory process occurs to heal and regenerate the damaged fibers." That sounds like a good thing, right? Well, the inflammation is where that muscle soreness comes from too. There's also an increase of creatinine kinase, blood lactate, and the frequency of necrosis or cell death as a part of that recovery process. Those things are all due to damage. That's part of the strengthening process, right? I mean, there has to be some level of damage to the muscle and some level of inflammation to reinforce and strengthen those muscles. In the short term, though, it's kind of traumatic.
When we talk about recovering from this traumatic process of exercise, there are four different factors that we want to look at, especially if you're on the performance side of athletic output or if you're actively engaged in sport. But even if you're just engaged in your personal gym routine and you're looking for better gains, quicker gains and faster recovery after sessions have four different factors you need to consider:
recovery of function
soreness
muscle damage
muscle performance
The authors say that symptoms such as soreness and decreased muscle function are reported by athletes following strenuous exercise. This results in muscle fatigue; the muscle fatigue then alters muscle proprioception and inhibits the muscle's ability to function correctly. As a result, you would experience problems with stamina and coordination as well as reduced range of motion.
Muscle soreness actually limits the body's ability to perform. The authors say that cryotherapy has been used to limit soreness, and it is able to improve the subjective measures of soreness only. But muscle force and lactate, creatinine kinase, and inflammatory markers are all objective measures prevented from recovering to normal levels when ice is used.
By using ice, you might feel less sore, but you're actually slowing down your muscle recovery!
Light therapy actually gave better soreness relief than the cryotherapy did. Moreover, when we start looking at our other two factors of muscle damage and muscle performance, light therapy is far ahead of cryotherapy in terms of performance and damage and soreness alleviation.
The authors say that, compared with placebo-treated groups, cryotherapy showed no difference in creatine kinase or blood lactate levels at any time points. In those included studies, it was found that light therapy protected the muscle against damage, with significantly lower levels of muscle-damage markers. Consequently, they had lower inflammation markers, which is C reactive protein and leukocyte activity; they didn't observe that in the ice therapy groups.
Not only did light therapy do better for soreness recovery, but it also did better for controlling muscle damage and improving those damage markers.
The last factor that we're looking at when it comes to athletic recovery is muscle performance, which is highly important for getting the best performance you can as an athlete. If, as an athlete, you have good muscle-performance recovery, you can get back on the field sooner and perform better. These authors say that oxidative stress increases after intense exercise, which decreases the contractile function of the muscle. Basically, once you've worked the muscles hard, they lose the ability to contract as strongly. However, light therapy actually allowed strength to stay the same, and it prevented any decrease from occurring throughout exercise: "During repeated high-intensity muscular exercise[, light therapy] aided in preventing a decrease in maximum voluntary contraction." But when they tried ice instead of light, they had significant decreases in that maximum voluntary contraction. So, the final word on muscle performance recovery is that light therapy is able to maintain an athlete's strength whereas ice actually seems to diminish that maximum voluntary contraction.
In conclusion, not only could your ice regimen be hurting your muscle recovery, but it could also be impeding your muscles' ability to perform well.
So what are the takeaways from this piece of literature? Well, number one, stop icing. When we're talking about ice versus light, for all four factors that we looked at (the recovery of function, soreness levels, muscle damage, and muscle performance), light outperforms ice every time. Ice may actually be inhibiting the repair processes and the strengthening processes that your body has to undergo after physical exertion. So, you have to stop using ice. Icing feels good, and people have done it for a long time now. Your parents told you to; your instructors told you to. Heck, they've taught doctors about using ice after recovery for years now. But when we look at the science, ice is not beneficial . . . but light is.
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