Why one type of massage can help muscles heal faster — study
There’s a curious link between mechanical stimulation, skeletal muscle repair, and immune function.
Ah, massages. The process of having your body kneaded like bread dough is both an exercise in preference — and a scientifically-based way to improve your health, according to new research.
Do you like a light touch with fingertips flitting over your sore muscles, or do you want someone digging their elbow into your scapula with their full body weight? What about a massage gun, which somehow evokes both relaxation and violence in one item?
Massage guns, like the Theragun or Hypervolt, offer a type of mechanotherapy, which is when a mechanical device treats what’s ailing you. Unlike human hands, which can move and press with more nuance but less consistency, these tools offer percussive movement at an exact speed and pressure. For those who like being poked and prodded in their sore spots, this therapy might sound ideal.
Massage therapy has been employed and studied for thousands of years, and is shown to improve symptoms of conditions from fibromyalgia to depression. The biological mechanisms, however, have been less understood.
In a study published in October in the journal Science Translational Medicine, researchers from the Wyss Institute at Harvard University examined the benefits of massage as mechanotherapy, focusing on a massage gun-like device. While the study was on mice, the researchers found massage guns can potentially benefit people because of a relationship between mechanical stimulation, skeletal muscle repair, and immune function.
These findings suggest this form of massage can benefit those suffering from chronic musculoskeletal pain and generally people looking to overcome muscle injury.
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Why it’s a hack — After a muscle injury, the hurt tissue swells with inflammatory cells called cytokines. Cytokines trigger immune cells called neutrophils to descend as a biological response.
The study team suspected applied pressure from mechanotherapy would flush cytokines and neutrophils out of the injured muscle.
“So this is pretty cool.”
Neutrophils are crucial to muscle recovery at the earliest stages of healing, but can in fact become harmful if they stick around for too long. If they’re there longer than necessary, they can start attacking the muscle and hinder regeneration. By evacuating both the inflaming cytokines as well as the neutrophils, the muscles could heal effectively but also begin regeneration earlier.
“It turns out that the improved healing process with this mechanism therapy is in part through modulating immune responses,” lead author Bo Ri Seo, a postdoctoral fellow at the Wyss Institute, tells Inverse. “So this is pretty cool.”
Science in action — Seo and her colleagues tested their hypothesis about mechanotherapy on mice, and if you’re imagining a teeny tiny spa for wee little mice, that’s understandable but unfortunately not what happened. Rather, the team built a compression device that performs the same role as a massage gun, but for a mouse.
First, they surgically induced ischemia in the mice, hampering blood flow to their leg muscles so the muscles became severely damaged. This process created the injury the team wanted to evaluate.
The mice then underwent mechanotherapy while the scientists monitored the machine’s compression and performed an ultrasound on the leg.
This was in order to watch muscle deformation in response to the machine. They noted how the mice healed over 14 days with mechanotherapy versus without it, and also how compressive forces, measured in Newtons, had the optimal effect.
According to Seo, between 0.15 and 0.6 Newtons from the mechanical massager had the greatest healing effect on the muscle within the two-week period compared to other pressures, or none at all. This range of forces generates 10 to 40 percent deformation of muscle relative to its original size.
However, muscles of varying sizes will require varying forces for optimal healing. Seo’s team applied mechanotherapy to the mice’s tibialis anterior. In humans, this would be the thick muscle along our shin bone connecting our knees and ankles.
The team also created a computational model that could actually optimize force from the compressor and its effect on the muscle. They were able to build a model that spits out what frequency and force are necessary to have a certain influence on muscle.
What this means exactly for humans is to be determined — the team wants to scale up the research to larger animals, like rabbits, next. But they anticipate that these results will support, and eventually explain, previous findings which suggest massage therapy benefits injury.
“We don't know yet that this method [has a] similar impact in terms of making new muscle fibers or making different types of muscle composition as we saw shown in this paper,” Seo says. So should people try a massage gun?
“We know that massage therapy is already helpful in terms of making patients feel better, so if people want to feel better, yes, of course, why not?” Seo says.
How this affects longevity — It’s known that frequent exercise improves life quality and longevity, and we need healthy muscles in order to get exercise. But as we age, our muscles inevitably atrophy, and we lose muscle mass.
“It creates a vicious cycle,” Seo says. “If you lose muscle mass, you can’t really do much physical activity, and that basically prevents gaining muscle mass.”
A muscle injury early on can hinder the continued growth of muscle mass, so if left untreated a muscle injury can be quite debilitating. Mechanotherapy could perhaps spur muscle regeneration in our later years — which would allow us to live actively with healthier bodies. It’s a much better cycle.
So whether you love, hate, or don’t really care about massages, this research suggests mechanotherapy, in particular, is worthwhile. And maybe it means you should open up that mouse spa you’ve been thinking of.
HACK SCORE OUT OF 10 -- 🐭🐭🐭🐭🐭🐭 (6/10 lab mice)
Editor’s note, 10/19/21: This article has been updated to revise how the compression was measured in Newtons.