Tag: Muscle Mass

In Fitness

Muscle Cells Attenuate Effects of Inflammation

Have you ever had one of those situations in life where somebody asks you a question of why something is and you can’t put into words the explanation.

For example, imagine a young toddler asking why is the sky blue?

What would you say? How would you explain it?

It’s something we know to be true but hard to put into words.

The same could be said for the benefits of exercise. We have known for a while that exercise helps with inflammation. But we didn’t know which cell type(s) were involved? And could this help maintain strength?

A research team at Duke University has been looking to answer this question. Specifically they wanted to see how effectively muscle cells would be at warding of chronic inflammation. This is different from acute inflammation that results from a specific episode such as a sprained ankle. When we roll an ankle playing pick up basketball there is an immune response to clear away cellular debris and helps the tissue heal.

Other times inflammation can extend over long periods of time causing damage and weakening tissues i.e. rheumatoid arthritis and sarcopenia. This type of chronic inflammation induces muscle atrophy. Exercise can counter these negative side effects.

The researchers were able to engineer muscle cells in-vitro i.e. in a petri dish. These cells were then exposed to interferon gamma for seven days. We normally see this chemical messenger elevated in muscle cells of those with chronic inflammation.

After the seven day period of exposure to interferon gamma, to induce a situation of chronic inflammation, the researchers then stimulated the muscle cells electrically to make them contract.

What they found was that the muscle cells that exercised i.e. that were electrically stimulated, did not show the effects of chronic inflammation. With long term inflammation, i.e. chronic inflammation, there is atrophy, or loss, of muscle tissue. This did not happen with the muscle cells that were electrically simulated.

What’s even more interesting is that the experiment only involved muscle cells. Typically we might associate health benefits with immune, stem or other type of cell. This is a new discovery of linking the protection from inflammation directly to muscle cells.

And as the images below show, exercise helps prevent the atrophy of muscle that typically is associated with chronic inflammation. If you stay active, particularly with resistance exercise, your muscles won’t get smaller and weaker.

The top L box shows muscle cells (red) in the control condition. In the top R we can see how inflammation changes the structure of the muscle cells. However in the bottom L adding exercise to the mix protects the muscle cells from the damage of inflammation.

We can train for a variety of reasons and this adds another very important reason to make sure we lift weights. This is especially true for those that suffer from inflammatory diseases such as asthma, celiac, diabetes, rheumatoid arthtitis, obesity and more.

Chen, Z., Li, B., Zhan, R. Z., Rao, L., & Bursac, N. (2021). Exercise mimetics and JAK inhibition attenuate IFN-γ–induced wasting in engineered human skeletal muscle. Science Advances, 7(4), eabd9502.

In Fitness

Training While Injured to Prevent Muscle/Strength Loss

There’s an expression in sports that ‘you play, you pay’. And this refers to getting injured.

You play frequently enough and push yourself enough and you will suffer an injury. It’s not a case of ‘if’ but ‘when’.

Most athletes know what I’m talking about and have spent time in an ER, in a sling, on crutches or a wheelchair. I’d have to say being injured is the worst part of sports. Worse than losing.

Because when you’re injured you can’t play. You can’t help your team. And if things aren’t going well it’s even worse. You have to wait it out, go for your rehab appointments and wait for the OK to return to training and competition.

A recently study looked at how training the non-injured side minimized the losses that typically occur to the injured side.

What the researchers did was have 30 subjects, male and female, between 18-34 years, put their non-dominant arm in a sling for 8 hours per day. The elbow was bent to 90 degrees and then immobilized for the 8 hours. The non-dominant arm was determined as the non-writing arm.

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All subjects had the non-dominant arm immobilized for 8 hours per day.

The 30 subjects were then assigned to one of three groups. The first group did no exercise, the second did eccentric and concentric exercise and the third group did eccentric only exercise. The tempo for the eccentric and concentric group was 2 seconds up and 2 seconds down. And for the eccentric group the participants took 4 seconds to lower the weight. The exercise performed was a biceps curl over a preacher bent with a dumbbell. For the eccentric only group the researcher grabbed the dumbbell at the bottom of each rep.

Participants did 3-6 sets of 10 reps of dumbbell preacher curls for 4 weeks.

For the next 4 week the subjects performed this exercise 3 times per week with 3-6 sets of 10 reps. For the eccentric and concentric group the loads ranged from 60-90% and for the eccentric group the loads ranged from 80-120%. For both groups the loads increased 10% each week.

The researchers wanted to see the impact this would have on arm circumference, one repetition maximum strength (1 RM), maximal voluntary isometric contraction, rate of force development and joint position sense.

So what did they find?

The group that did no exercise lost the most muscle and in this case they lost 28% of their arm muscle mass. The two exercise groups lost less strength and arm size with the losses being less with the eccentric only group. In fact, the biggest increase in strength was with the eccentric only group and there was only 2% muscle wastage in the immobilized arm.

Besides injured athletes this research is also valuable for those who have suffered a stroke. If you find yourself unable to exercise one limb make sure to continue with the exercise. But don’t just do any type of exercise as in this case eccentric only training did the best job of maintaining strength and minimizing losses.

Valdes, O., Ramirez, C., Perez, F., Garcia‐Vicencio, S., Nosaka, K., & Penailillo, L. (2021). Contralateral effects of eccentric resistance training on immobilized arm. Scandinavian Journal of Medicine & Science in Sports, 31(1), 76-90.