WHEN injuries happen, oftentimes, they happen only on one side of the body. You would be hard pressed to sprain both of your ankles at the same time, or when having a ligamentous tear on the knee, normally it happens on only one side. More often than not, we wait for the affected area to heal before we start exercising or rehabilitating.
Not anymore though. “Mirroring,” a term coined by researchers, has shown immense promise. An exercise intervention on the opposite side can lead to significant gains even on an immobilized side. In layman’s terms, even if your left arm is broken and casted, training the right arm can retain the strength and mobility lost by the left. How is this possible? The brain tells the left side of the body to retain its strength and function even when it is not being used.
Is there any scientific evidence? Surely!
Researchers from Canada gathered 16 male and female college students and closely examined their wrists. Using various imaging, the scientists determined the precise dimensions of two separate sets of muscles in that joint: the extensors, which move the wrist back and away from the body; and the flexors, which pull it in, toward the forearm.
The researchers also tested each volunteer’s wrist strength using a weight machine for the hands. Then they covered each student’s left forearm and wrist with a hard cast to freeze the wrist in place. Half of the students were then asked to go on with their normal lives, ignoring the cast as much as possible and not exercising their arms.The other eight students, though, began a workout program that targeted the flexor muscles in their wrists. Using a small, vise-like weight machine, they completed multiple strenuous contractions of those particular muscles. The researchers also attached tiny sensors above the flexor muscles in the volunteers’ immobilized wrists to measure any contractions there.
After a month, all of the volunteers returned to the lab, had their casts removed and repeated the original measures of their muscles. As expected, the volunteers who had not exercised showed considerable muscle atrophy now. Their left wrist flexors were more than 20 percent weaker, on average. Those muscles also had shrunk in size, dropping about three percent of their mass.
But the group that had exercised their right wrists’ flexor muscles had maintained almost all of those muscles’ original size and strength on the left. The benefits were quite specific, though. These same volunteers’ wrist extensor muscles, which had not been exercised in their right wrists, were atrophied on the left.
So you see, when hurt on the left, train the right side. Hope this helps everyone struggling through a broken arm or leg.