You might see a lot of complicated terms thrown around in the fitness world. One, in particular, you might have heard is isotonic exercise.
You might be wondering, what are isotonic exercises? Is this some new workout fad my trainer’s going to put me on?
You’re probably already doing isotonic exercises. It’s nothing new, just a way to describe the science behind how certain exercises work. Read on to learn all you need to know.
What are Isotonic Exercises?
An isotonic exercise is an exercise that forces the muscles to contract and expand throughout a full range of motion, while working against some form of resistance.
The word isotonic technically means “same tension”. In terms of isotonic exercises, it means you’re maintaining the same tension on the muscle (which could be the weight of a barbell or dumbbell, your bodyweight, or gravity) throughout a movement, as your muscle contracts.
The idea is that an isotonic exercise results in a change to the length of the muscle that’s being worked. Using a bicep curl as an example, your muscle contracts when you lift the weight, and expands when you lower it. This is an isotonic movement, and if done consistently, will result in a longer (and bigger) bicep muscle.
What are Examples of Isotonic Exercises?
Most exercises you already do are likely to be isotonic exercises. As long as you’re moving your joints, and causing muscle contraction against some form of resistance, you’ve got an isotonic exercise.
- Resistance training exercises (i.e. curls, bench presses, deadlifts, squats, pull-ups)
- Aerobic exercises (i.e. running, swimming, cycling)
- Most sports movements (i.e. throwing a punch, throwing a football, swinging a bat)
Even everyday activities, such as mowing the lawn or painting a fence likely count as some form of isotonic exercise.
What's the Difference Between Isotonic and Isometric Exercise?
It sounds like isotonic exercise covers just about everything. Is there anything that’s not an isotonic exercise?
Yes. You’ve also got isometric exercises.
Isometric training involves engaging a muscle without moving your joints and without lengthening or shortening the muscle.
There are fewer exercises that utilize isometric muscle contraction out there, but you should still be familiar with some of them. Stationary exercises focused on constant muscle tension, like planks, wall sits and many yoga poses are examples of isometric exercise.
These exercises still work the muscles, but do so in a different way than the contracting-expanding nature of isotonic exercises.
What are the Two Forms of Isotonic Exercise?
When we’re talking about isotonic exercises, you might also come across the terms “concentric” and “eccentric” in relation to an isotonic movement.
These terms relate to the different ways in which muscles contract. A concentric movement, or contraction, is when tension on a muscle causes it to shorten.
Eccentric is the opposite. It’s a lengthening movement of the muscle, where tension causes the muscle to stretch and become longer.
Concentric Isotonic Exercises
Bicep curls are a common example of a concentric movement, as are most basic lifting movements. The most important part of these exercises is when you bring the weight towards you, shortening the muscle or muscles used.
Situps and hamstring curls are other examples of concentric isotonic exercises.
Eccentric Isotonic Exercises
Eccentric movements are the opposite - it’s when the most important part involves a weight going away from you, in a pushing motion for example.
Squats are a good example of an eccentric isotonic exercise, as are tricep extensions, calf raises, and walking.
A lot of isotonic exercises involve both concentric and eccentric movements. Take a bicep curl for example.
The up motion is a concentric movement, or a shortening of the muscle. If done correctly, you should follow that by slowly lowering the dumbbell, retaining the same tension, in an eccentric movement as the muscle lengthens.
Push-ups, pull-ups, rows, bench presses, and many more are also examples of exercises with both concentric and eccentric movements. In fact, it’s probably less likely to find an exercise that only involves one of the two.
What are the Benefits of Isotonic Exercises?
One of the top benefits of isotonic exercises is how they replicate regular movements, and therefore translate into better functional strength, outside of the gym. Going through a full range of motion also activates a larger number of muscle fibers, for more overall growth.
Isotonic exercises are also generally convenient and easy to do with whatever equipment is available to you. Isotonic training incorporates resistance exercises, such as a free weight, instead of any specific machines or tools.
There are a number of additional benefits, not exclusive to isotonic movements, but which we should certainly mention, including:
- Increased muscle mass
- Increase strength
- Better cardiovascular health (lower blood pressure)
- Stronger bones
Who Should Perform Isotonic Exercises?
Isotonic exercises are a good fit for just about anyone. You might think that isotonic exercises are basically just strength training, and only worthwhile for people who want to build big biceps or pecs.
While isotonic exercises absolutely are great for building muscle mass, they’re still worthwhile if that’s not your goal.
You can perform these exercises in a number of ways, varying the weight, reps, sets, and rest periods, to achieve different outcomes depending on whether you want to bulk up or slim down.
You can also vary the intensity to fit where you are in your athletic journey - whether you’re a professional athlete, or just trying to get in shape for the first time.
Isotonic exercises are particularly valuable as people age. Resistance training helps improve bone density, which declines as we get older, often leading to osteoporosis.
The only exception, who perhaps should stay away from isotonic exercises, are people who are dealing with an injury - particularly joint injuries. Some low-intensity isotonic exercises might still be doable, but these people may find it easier and safer to do isometric exercises instead.
How to Best Perform Isotonic Exercises
Each isotonic exercise has its own form, which is extremely important to get right, particularly under heavier resistance.
You might hear experts refer to something called isokinetic exercise. This is not the same as Isotonic exercise. To quickly define it, the word "isokinetic" refers to using exercising at the same speed throughout each movement.
In most cases, however, the basics are the same. You want to try and keep the tension the same throughout the movement. After all, this is what the word “isotonic” means. In a way, you could perform both an isotonic and isokinetic exercise with the same movement as long as you maintain the same speed throughout.
To do that, you’ll want to be slow and deliberate with how you lift and lower the weight (whether that’s a barbell, a free weight, or your own body weight). Try and pay close attention to how the concentric and eccentric contractions work throughout the overall movement.
How to Stretch Before Isotonic Exercises
For all kinds of exercise, it’s a good idea to stretch beforehand. This will warm up your muscles, as well as loosen up your muscles and joints to help avoid injury.
A dynamic stretching routine is great for this. Dynamic stretching works well as a warmup, and gets your body ready to undergo lifts at a full range of motion.
If you have time, it’s best to hit every part of the body with your stretching routine, to make sure each muscle group is warmed up.
Common Isotonic Exercises Examples
There are many ways to utilize isotonic exercises in your workout routine, depending on your overall workout goals.
If you’re starting out, here’s a sample workout you can do, hitting a number of muscle groups up and down the body.
Chances are, you're already doing a combination of these exercises for your workouts.
Exercise 1: Bench Press
The bench press primarily works your pectoral muscles, though activates a number of smaller stabilizer muscles and secondary muscle groups. It’s a great exercise for anyone, of any level.
Alter the weight depending on your goals and your fitness level. Alternatively, substitute this for push-ups if you prefer a bodyweight exercise, or you don’t have the equipment to do bench presses.
Exercise 2: Pull Ups
Pull-ups are going to target your back and arms. The best part about pull-ups is that they use your bodyweight, which means it’s a lot harder to get injured than stacking a large free weight on top of yourself.
Exercise 3: Squats
Add squats to target (primarily) the lower body. Like with the bench press, alter the weight to suit you, or even do unweight if needed.
Exercise 4: Sit Ups
Finally, add sit-ups to target your abs and core. The isotonic movement in sit-ups involves a contraction of your abdominal muscles - which, done consistently, will probably deliver a six-pack, which most of us would love to have.
So there are a few isotonic exercises you can work into your routine. As mentioned, a lot of what you’re already doing probably counts as isotonic exercise anyway.
Whatever your workout includes - isotonic, isometric, or otherwise - the important thing is just to be active. Any workout is better than no workout.