Muscular Fitness · Updated August 2026

Why Muscular Power is Essential for Fitness & Function

Power is the first thing you lose, and it starts around age 30. It is also the easiest to keep, once you know how to train for it.

When you hear the term muscular power you probably think of an image of an athlete explosively playing their sport. If you did, you wouldn’t be wrong. But you should also think of an image of getting out of a chair, getting up from a toilet seat, preventing a fall, and many of the functional tasks we perform on a daily basis.

The need for muscular power is essential for function and doing the physical activities we enjoy. The problem is it declines starting at around the age of 30. The good news is that with properly performed resistance training you can greatly slow the loss of muscular power ensuring you’re able to maintain your functional capacity and do all the activities you like to do. We’ll dive a little more deeply into muscular power in this article, as well as how to effectively and safely improve it.

What is the Definition of Muscular Power?

Muscular power is force multiplied by velocity: how much force you can produce and how fast you can produce it. Muscular strength is force alone, with no clock running. Lifting a heavy box onto a table is strength. Standing up out of a chair without thinking about it is power.

Often, the words power and strength are used interchangeably when talking about muscular fitness, but they are not the same. I hate to take you back to your high school physics class, but we’ll have to really quickly to understand the difference. Muscular strength is the ability to produce force, independent of speed. Basically, move an object from point A to point B. No matter how fast you move it there, you’ve completed an act of strength. It’s all about the force produced. A real-world example of strength is picking up a heavy box of books from the ground and putting it on a table. It doesn’t matter how fast you move the box; you just need to get it on the table.

Muscular power, on the other hand, is the byproduct of both strength (or force) and speed (or velocity). This is where your old physics teacher would remind you that power = force X velocity. The velocity component is the critical factor, for an activity to involve muscular power you’re producing force at higher speeds. A real-world example here is climbing stairs. You might not think about it, but climbing stairs requires power. It requires enough strength in your legs to overcome the weight of your body and enough speed of contraction to propel you up the stairs. Getting up from a chair is another example, people don’t get out of a chair slowly. In fact, if you think about the many recreational activities you want to perform, they probably involve an element of power.

Muscular Strength vs. Muscular Power

Select each one to see how they differ, and where each shows up in your day.

Force only
How much you can move

Strength is the force your muscles can produce, independent of speed. Move the object from A to B and you have completed an act of strength, no matter how long it took. In daily life that is a heavy box onto a table, a suitcase into an overhead bin, a bag of soil out of the trunk. Most people who resistance train are training this quality, and it is worth training.

Force × velocity
How fast you can move it

Power adds a clock. You still need force, but you need to produce it quickly. In daily life that is standing up out of a chair, climbing a flight of stairs, catching yourself when a curb comes up sooner than you expected, or keeping up in a pickleball rally. Very few people train this quality, which is why it fades first.

Don’t get me wrong, strength is certainly important, and I would argue that a foundational base of strength is critical for health, but most people recognize this. As a result, they’ll perform resistance training to improve strength, but not power. This is a big mistake if you want to be functional and active as you get into your 30’s, 40’s and beyond. I’ve made the case elsewhere that muscular fitness is the rate limiter for everything else in your health, and power is the part of muscular fitness almost nobody trains.

Loss of Power with Age

Writing the words “with age” might suggest something that happens in the last third of life, but that’s not true with all aspects of muscular fitness, and it’s certainly not true of muscular power. Most of you reading might be familiar with the term sarcopenia, which means age-related muscle loss. Most people also seem pretty aware they lose muscle mass with age (especially if they’re not resistance training). While sarcopenia isn’t good, it’s not actually the first element of muscular fitness that declines. If you thought it was strength, guess again: strength does decline before muscle mass does, but power is the first thing to go. As I said in my opening, it can start to decline around the age of 30, and depending on your activity level, it can decline rapidly. Later in life, loss of muscular power can be so great that fall risk increases (and falls lead to a whole host of other severe problems like fractures and concussions).

~30
The age muscular power begins to decline, decades before most people think aging starts.
Gava et al., Exp Aging Res
1st
Power goes before strength, and strength goes before muscle mass. The order is why power gets missed.
Applied Fitness Solutions
1
Power declines first
Around age 30, the speed side of the equation starts slipping. You will not notice it, because nothing in a normal day asks you to move quickly on purpose.
2
Strength declines next
Force production follows. This is the point where heavier tasks, like carrying a full laundry basket up a flight of stairs, start to feel like work.
3
Muscle mass declines last
Sarcopenia is the part people know about and the part that shows up in the mirror. By the time you can see it, the qualities that keep you functional have been fading for years.

I won’t get into all the science behind this decline in power, but I’ll give you a high-level view by explaining what happens to our muscle fibers.

Fast Twitch vs. Slow Twitch Muscle Fibers

First, you should know that we have two types of muscle fibers: fast and slow twitch. The fast twitch muscle fibers are bigger, stronger, and produce power very well. The slow twitch muscle fibers are smaller and not as good at producing strength and power, but they are great at resisting fatigue. Every muscle is made up of both fast and slow-twitch muscle fibers. This is largely based on genetics and likely explains why some people are good at running distances (because they have a lot of slow twitch fibers) and some people are good at sprinting (because they have a lot of fast-twitch fibers).

The Two Fiber Types

Select each one to see what it does well, and what training does to it.

Power fibers
Bigger, stronger, faster to fatigue

Fast twitch fibers produce power very well. They are what a sprinter leans on, and what you lean on when you stand up quickly or catch a stumble. They are also the fibers that convert toward slow twitch as you age if nothing in your training asks them to work.

Endurance fibers
Smaller, and built to keep going

Slow twitch fibers are not as good at producing strength and power, but they resist fatigue beautifully. They are what a distance runner leans on. Train for endurance only, and your fast twitch fibers start behaving more like these.

Now, here’s the important thing to know about these muscle fibers: they can alter their characteristics through exercise. Train to be stronger and more powerful and the slow twitch fibers will start to perform like fast twitch fibers. Train for endurance and the fast twitch fibers will start to become more like slow twitch fibers.

Alright, I’m almost done with our anatomy lesson here. The last thing to know is that as we age, if we don’t do anything about it, the fast twitch fibers naturally turn into slow twitch fibers. It’s a bit more complicated than I’m letting on here, but the important thing to know is without the right kind of resistance training your muscles will get smaller, weaker, and slower as you age. Fear not, though; all is not lost.

Resistance Training to Improve Muscular Power

The most important words in that paragraph above are “if we don’t do anything about it.” As with most things in our body, our muscles operate off the use it or lose it principle. No doubt aging is real, but we all know 60-year-olds who are as fit and functional as 30-year-olds and vice versa. The difference here is (mostly) they’re still using it, so they haven’t lost it. Sure genetics plays some role, but research suggests that exercise plays an even bigger role than genetics. Now, I’m not saying exercise can turn back the clock back to high school glory days, but it can do a heck of a lot to help you keep much of your muscular capacity as you age, provided you’re training properly.

When I talk about training properly, I’m talking about doing resistance training in a structured and progressive manner that incorporates a training style that builds a base of muscular strength first and then improves power. My observations from a three-decade career as an exercise professional tell me very few people conduct resistance training properly as they age. Worse yet, the people I’m observing are the people AT THE GYM, so at least they’re doing something. Everyone else is doing nothing and literally wasting away in the process (I know that sounds dramatic, but go with me on it, as it’s not that far off).

Most people who do resistance training don’t do it with adequate load or adequate speed to improve muscular strength or power. In fact, as people age (into their 60’s and beyond) they progressively lift lighter and lighter weights, only improving their muscular endurance. While endurance is important, it’s not the key to function; strength and power are, and they need to be trained for. Better yet they can be trained for. Research demonstrates that even people in their 80s and 90s can improve muscular strength and power. As long as you’re not over the age of 99, you can benefit from adding resistance training for strength and power into your exercise routine.

Where the lighter-weight habit comes from: a lot of people were taught that high reps with light weight is the safe option as you get older. I wrote about why that idea does not hold up in High Reps Tone, Low Reps Bulk. Very light weight moved slowly trains endurance, and endurance is not what keeps you out of a chair.

Muscular Power Self-Check: The 30-Second Chair Stand Test

Everything above is easier to act on once you have a number. The 30-second chair stand test, also called the 30-second sit-to-stand test, is the field measure clinicians use to check lower body strength and power. The CDC includes it in its STEADI fall prevention toolkit, and it needs nothing but a chair and a timer.

How to take the test
Set up Firm chair, no arms Roughly 17 inches high, backed against a wall so it cannot slide.
Position Arms crossed at the chest Hands on opposite shoulders, feet flat on the floor, back straight.
The test 30 seconds, full stands Rise to a full stand and sit back down, as many times as you can.
Scoring Count complete stands If you have to push off with your arms, the score is zero. Count a stand if you are more than halfway up when time expires.

The CDC publishes below-average scores by age and sex. Falling under the number for your group is a sign that lower body power deserves attention, and it is one of the reasons clinicians use this test to flag fall risk.

Below-average 30-second chair stand scores (CDC STEADI)
AgeMenWomen
60–64Below 14Below 12
65–69Below 12Below 11
70–74Below 12Below 10
75–79Below 11Below 10
80–84Below 10Below 9
85–89Below 8Below 8
90–94Below 7Below 4

Published norms begin at age 60. If you are younger, use the 60–64 numbers as a floor you should clear comfortably, and use your score as a baseline to beat when you retest.

Take the test, then enter your score below. The self-check compares it against the CDC numbers for your age and sex and points you to the training phase to start with. It is for reflection, and it does not diagnose anything. If standing up has become difficult, or you have had a fall, bring that to your doctor.

How to Improve Muscular Power

I hope I’ve convinced you by now that resistance training for power is important. The last question becomes how do you do it? I’ll explain that briefly here with a couple of caveats.

First, always consult your physician before beginning an exercise program if you have any reason to believe there could be issues. Secondly, the best way to get a safe and effective resistance training program is to work with an exercise professional (ideally one who has a degree in the field and is credentialed through the American College of Sports Medicine).

The Four Phases at a Glance

Select a phase to see what changes. Each one runs about a month.

Start here
Build technique and tendon strength

Movements stay technically simple, loads stay low, reps stay high. Nothing here is meant to be impressive. It is meant to prepare your tendons and your movement quality for the harder work coming in phases three and four.

Bridge
Drop the reps, add the weight

Slightly more intense training, without focusing on strength or power just yet. This phase begins the transition to eventually training for power.

Force
Low reps, heavy loads

Now you train the force side of the power equation. Remember the physics: power = force X velocity. Without force, there is nothing for speed to multiply.

Velocity
Low reps, lighter loads, moved fast

Reps stay low, loads come down, and intent goes up. You will see a lot of body weight and band movements here, which is a safe way to train the speed side. Then you go back to phase two and run the cycle again.

The Four Phases, Step by Step

Those two items aside, here are the steps I recommend you take to build muscular power through resistance training:

1. Build a good base of technique and tendon strength

This is done by spending 1-3 months in a beginner phase of resistance training. Movements should be kept technically simple, loads can be low, reps can be high. This type of training builds a base that will allow you to do more rigorous forms of training in the future. The workout below is a good example.

An example of a beginner resistance training workout

2. Drop the reps a bit and increase the weight you’re lifting

Here, we’re progressing to slightly more intense training, but not focusing on strength and power just yet. This phase (example below) begins the transition to eventually training for power.

Example of resistance training with increased weight to build muscular power

3. Lower the reps, increase the loads, and train for strength

This type of training will focus on the force production piece, as it’s a foundational piece of the power equation (remember physics from above power = force X velocity). The workout below is a great example of this kind of training.

an example of resistance training for force production and muscle power

4. Keep the reps low, reduce the loads, but move them faster to train for power

In this phase of training, we focus on movement speed more so than load. You’ll notice in the example workout below there are a lot of body weight and band movements. This is a great way to train for power safely.

example resistance training program incorporating speed

5. Repeat steps 2-4 over and over again

You can essentially do this forever, spending one month with each of those styles of training. This will always give your muscles a new stimulus to adapt to and, most importantly, ensure you’re continually improving muscular power to ensure you’re able to keep doing all the physical activities you enjoy.

A note on jumping: people often hear “power training” and think plyometrics. True plyometric work is a maximal-effort method with a real skill and readiness requirement, and it is not the starting point for most adults. I covered where it fits and where it does not in Is Plyometric Exercise Good For Weight Loss? The band and body weight work in phase four gets you the speed adaptation without the landing forces.

One more thing worth saying: training for power will not leave you especially sore, and that is fine. Soreness has never been a good measure of whether a session worked, which I went through in Is Soreness an Indicator of a Good Workout? Judge phase four by whether the bar, the band, or your body is moving faster than it did last week.

Take Home Message: Muscular Power – Use it so you don’t lose it

What I’ve laid out in this article is what the scientific evidence tells us about staying fit, healthy, and functional as we age. Remember when we’re talking aging from a muscular standpoint: this starts at around 30 (I know, that hurts). The good news is that you can take control of your health by doing what I’ve laid out in this article. How do I know? I’ve been doing it with people just like you (in their 30s, 40s, 50s, 60s, 70s, and even 80s and 90s). I see it every day at Applied Fitness Solutions, people resistance training the right way to live the lives they want to lead. You can do it too, if you use it, I promise you won’t lose it!

If you want help putting the four phases in the right order, talk with an Applied Fitness Solutions health coach. Bring your chair stand score with you. It is a useful place to start, and a satisfying number to beat.

Keep the Power You Have

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Michael E. Stack, Founder and CEO of Applied Fitness Solutions
About the Author
Founder & CEO, Applied Fitness Solutions & Frontline Fitness Pros

Michael Stack is the founder and CEO of Applied Fitness Solutions, the Michigan Moves Coalition, and the President of the Physical Activity Alliance. He is an exercise physiologist by training and a health entrepreneur, educator, and policy advocate by trade, dedicated to making exercise professionals an essential part of healthcare delivery.

With a career spanning over three decades in fitness, health, and wellness, Michael holds credentials through the American College of Sports Medicine as an Exercise Physiologist (ACSM-EP), Exercise is Medicine practitioner (ACSM-EIM), and Physical Activity in Public Health Specialist (ACSM-PAPHS). He is a Fellow of the Medical Fitness Association and lectures nationally for ACSM, ACLM, and the MFA.

This article is for informational purposes only and does not constitute medical advice. The 30-second chair stand test is a self-check, not a diagnosis. Before starting a new exercise program, check with a medical provider, especially if you have a health condition, have had a fall, or have been inactive for an extended period.

Sources

  1. Gava P, Kern H, Carraro U. Age-associated power decline from running, jumping, and throwing male masters world records. Experimental Aging Research, 2015.
  2. Cleveland Clinic. Sarcopenia (Muscle Loss): Symptoms & Causes.
  3. Schilke JM. Slowing the aging process with physical activity. Journal of Gerontological Nursing, 1991.
  4. Marzuca-Nassr GN, et al. Muscle Mass and Strength Gains Following Resistance Exercise Training in Older Adults 65–75 Years and Older Adults Above 85 Years. International Journal of Sport Nutrition and Exercise Metabolism, 2024.
  5. Centers for Disease Control and Prevention, STEADI. Assessment: 30-Second Chair Stand.
  6. Stack M. Is Strength Training the New Cardio? The Role of Muscular Fitness in Health. The Wellness Paradox.
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