Muscles and Aging – University of Iowa Mini Medical School

The Carver College of Medicine offers “Mini Medical School”, a series that presents aspects of medicine to the community. The fee is nominal and comes with dinner. Believe me, I figured my kids would be most interested in the all-you-can-eat taco bar. But they really enjoyed the first night of “Breakthroughs in Medicine at Iowa: The Science of Sports”. As did I.

A group presented Santos, a virtual person used to stress test new developments for the military and athletics. Included in this project are a number of departments working together, including biomechanical engineering, physical therapy, human physiology, and athletic training.

I was surprised to learn the limits of Santos; that is, I expected we already had virtual testing like this that was even more advanced. I may just be watching too much scifi thrillers. Reality is that the software looks less like Call of Duty and more like Doom from the 1990s. Not to knock it: it’s about data not aesthetics, and brings in plenty of money from military grants.

An MD-PhD student presented information on sudden cardiac death. Apparently, it’s not rare among adult athletes (1 in 50,000) but rarer among the entire population when you include student athletes (1 in 200,000). This research was following not just structural problems but ion channels — the movement of electrical signals via potassium and sodium. To prevent death, patients can now have a defibrillator implanted in their chests. Yes — just like the AED that you typically attach with pads and yell “clear!” before jolting the unconscious person.

But the highlight of my evening was the physical therapy professor who spoke on muscle fatigue and aging.

Muscles and Aging

Here are some interesting facts:

As you age, your muscular endurance increases but your muscle strength decreases. Likely this is the result of the conversion of fast twitch to slow twitch muscle fiber.

Fatigue and strength are a function of personal differences, gender, age, conditioning, and joint. That is, each joint has its general strength and fatiguability. Your ankle has the most endurance. Your shoulder, the least.

Women have more muscle endurance than men in the lower body. Both men and women have the same endurance in the upper body.

When measuring endurance, researchers use a percent of your maximum lift using an isometric hold for the longest duration you can sustain. What this means is as you age and your strength decreases, you feel like you have less endurance because you used to hold, say 10 pounds for 5 minutes and now can’t hold it that long. But what’s really happening is that 10 pounds is now a greater percent of your strength. See? If you still measure yourself at the same percent of maximum you would find you can hold longer.

Unfortunately, life isn’t about percents of maximum. It is functional. You’re lifting your whole body or a standard bag of groceries. That means, it feels like you ARE losing endurance because you’re losing strength. But here’s the thing: you can do strength training and see a reduction or even an increase in muscle strength and mass even after age 65.

Recommendations for physical fitness for all Americans includes:

  1. Don’t be inactive. However much and whatever way you move during the day is better than not moving at all.
  2. Each week, get about 150 minutes of moderate-intensity aerobic activity (your heart rate and breathing rate increases but you can still converse and continue the activity without a break) or 75 minutes high-intensity aerobic activity (your heart rate and breathing rate increase and you can only speak short sentences and need rests).
  3. Each week, get two strength-training sessions. Ideally, this includes exercising all muscle groups twice (chest, back, legs, shoulders, arms, core).

This is what the American College of Sports Medicine has recommended for a years, but now the government is spreading the message. You can find all sorts of work outs online (start at the American Council on Exercise), you can join a local gym, or you can talk to us about personal training in our studio!

Shannon and I work with teens and adults from age 15-78. My own experience has proven the information shared at the mini medical school is true: my older clients are almost always lifting more than my younger ones. However, the younger clients usually have more aerobic capacity. It’s rewarding to see the differences and train to those differences, as well as preferences our clients have for personal goals.

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2 Responses

  1. Paul says:

    Your comparison of the Santos graphic image to computer game graphics is not a valid comparison. Game graphics are pre-designed on high-end graphics terminals. These are captured as video clips for the game. Thousands of design hours and several million dollars are spent to create the latest GFIs. Santos software creates the human images in real time on a standard PC or laptop.

    The purpose of Santos is to allow design engineers to test their products one the fly, changing and retesting repeatedly; each time improving the customer experience, or uncovering manufacturing tasks that can cause injuries to employees.

    • Teresa Heitman says:

      I agree. That was my point when I wrote “not to knock it…” Games focus on aesthetics. Santos is about the data.

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