A man dressed in KYMIRA sportswear cycling on his Road Bike

Time to Read: 5 minutes

Points of Interest:
  1. Muscle Fibre Types

  2. Factors Involved in Muscular Endurance Improvement

  3. Training for Muscular Endurance

  4. What about Genetics?

  5. Example Workout for Muscular Endurance Training


Muscular endurance can be defined as your ability to repeat a physical action for a prolonged period of time. For example, a marathon runner or Tour de France cyclist must have great muscular endurance.

This is opposed to athletes who excel at muscular strength, like weightlifters or sprinters, where more explosive force is required over a shorter period of time.

This blog explains what muscular endurance is and how you can improve it.

Muscle fiber types

To understand muscular endurance, it is important to understand the muscle fiber types you have in your body and how they work.

Slow Twitch

As you begin to use your muscles for any physical activity, slow twitch muscle fibers are the first to respond. These fibers can sustain a low force over a long period of time.

Fast Twitch

When your muscles must endure a greater force than the slow-twitch muscle fibers can take, fast twitch muscle fibers are recruited. These fibers are larger and can generate higher amounts of force. These fibers will fatigue quickly and will require periods of rest.

Slow and Fast Twitch Activities

Depending on the activity you’re interested in, your body will need to be able to draw upon either slow or fast twitch muscle fibers.

Examples of Slow Twitch Muscle Activities

  • Running
  • Swimming
  • Power Walking
  • Cycling
  • Ironman

Examples of Fast Twitch Muscle Activities

  • Weightlifting
  • Sprinting
  • Crossfit
  • Basketball

When we are talking about improving muscular endurance, we are talking about improving our ability to perform slow twitch muscle activities for longer periods of time. Most activities don’t exercise exclusively one type of muscle or the other, but some activities do emphasize a specific type. You need to determine whether your goal is muscular endurance over a longer period of time, or muscular power over a shorter period of time.

For example, I am not an athlete and primarily perform gym-based activities to keep myself fit.

I balance my workouts between spinning twice a week and weightlifting three times a week.

Spinning trains my lower body for endurance, while weightlifting trains my entire body for power. So my lower body tends to have a balance of slow and fast twitch muscular performance, whereas my upper body is more adapted to fast twitch muscular performance.

If I were a triathlete, my training would be more geared towards slow twitch activities and muscular endurance for my entire body.

Factors Involved in Muscular Endurance Improvement

It is possible to improve your muscular endurance in sports like running and swimming. But there are a few things you’ll need to understand first:

  • On average your muscles will have an equal amount of fast and slow-twitch muscle fibers
  • When we talk about improving muscular endurance, we’re talking about strengthening slow-twitch muscle fibers
  • You can’t grow more slow-twitch muscle fibers, but you can train them for better performance
  • You can’t train fast or slow-twitch muscle fibers in isolation, any activity will train both types
  • Certain activities will result in increasing the proportion of slow twitch muscle fibers in a muscle. This is because the number of capillaries in the area increase, allowing for greater flood flow, therefore enabling you to perform the activity over a longer period of time.
  • Your genetics will also determine whether you’re more predisposed to endurance vs. strength (ability to train slow vs. fast twitch muscle fibers for improvement)

So, what’s the best method for improving muscular endurance?

How to Train for Muscular Endurance

Since slow-twitch muscle fibers are the key to endurance activities, it is necessary to choose training that will exercise them. However, fast-twitch muscle fibers still come into play.

Here are the main points for muscular endurance training:

  • Choose activities that feature sustained isometric contractions with little-to-no joint movement, such as front planks, side planks and single-leg balance
  • Resistance training should include lighter weights and slower movement for high numbers of repetitions (more than 15)
  • Use circuit training, involving going from one exercise to the next with little to no rest
  • Include high repetitions of body weight exercises, such as Calisthenics

What about Genetics?

Jason R. Karp, M.S. states:

“For maximum results, train your athletes according to their genetic predisposition. For example, an athlete with a greater proportion of slow-twitch fibers would adapt better to running more weekly mileage and a muscular endurance program, using more repetitions of a lighter weight. Likewise, an athlete with a greater proportion of fast-twitch fibers would benefit more from sprint training and a muscular strength program, using fewer repetitions of a heavier weight.”

While this is the ideal way to train, it’s difficult to test whether you have a greater proportion of slow or fast-twitch fibers. Also, there is evidence that certain genes can indicate whether you’re better suited for endurance or strength.

I had my DNA tested and the results were that I was more genetically predisposed towards endurance. In reality, I enjoy strength training and really don’t care for cardio exercise. When I asked about this, the company said that most importantly everyone should do the forms of exercise they enjoy. But knowing that I’m predisposed to better endurance, I should keep that in mind as I do my strength training. So higher reps with lower weights might be a better way for me to train.

Example Workout for Muscular Endurance Training

Perform each exercise once, rest for 30 seconds, then move to the next. Weights should be in the 60% of your 1 rep max range.

Repeat the entire circuit 3 or 4 times, 3 times a week

  1. Front plank: 30 seconds
  2. Bodyweight squats: 15 reps
  3. Bicep curls: 15 reps
  4. Pushups: 15 reps
  5. Walking lunges: 15 reps
  6. Jogging: 30 seconds

Bottom Line

Muscular endurance activities include swimming, running, cycling and other similar activities that involve a repeated motion over a longer period of time. Training for better muscular endurance involves improving the performance of your slow-twitch muscle fibers. Performing low-load, high repetition exercises is the best way to do this.

Also KYMIRA® Infrared clothing can help you to enhance your muscular endurance. Your peak performance zone will be extended and you will experience a reduction in session fatigue by wearing KYMIRA® clothing while exercising. This will allow you to increase training capacity and improve competitive performances. Sounds interesting? Check our performance range here.


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This article was written by Tim Powell, fitness blogger for Shrinkinguy.com. He promotes tips for eating well, exercise and healthy living.

October 22, 2018 — Tim Powell for KYMIRA Sport

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