Many people are entirely unfamiliar with isokinetic exercise, but isokinetic exercise can be a very valuable training tool in your fitness routine, particularly if you are recovering from an injury.
In this article, we will discuss isokinetic exercises, from the basic isokinetic exercise definition for those who are new to isokinetic exercise to a more detailed discussion of how to do it.
We will cover:
- What Is Isokinetic Exercise?
- Isometric vs. Isotonic vs. Isokinetic Exercises
- Benefits of Isokinetic Exercises
- Isokinetic Exercise Examples
Let’s dive in!
What Is Isokinetic Exercise?
Even if you’ve been working out regularly for years, there’s a decent chance that you haven’t heard the term “isokinetic exercise,” as it’s not as common to see isokinetic exercises in the fitness routines of everyday gym goers.
Therefore, let’s start with a basic isokinetic exercise definition:
Isokinetic exercise is a type of resistance training that utilizes specialized exercise machines that operate at a constant speed throughout the range of motion no matter what effort level you exert.
The prefix “iso–“ means “same.” For example, a plank is considered an “isometric“ exercise because the prefix “iso-“ means “same” and the suffix “-metric“ means length, and in the plank exercise, the muscles are not contracting to shorten or lengthen to stretch, so they are remaining the same length throughout the exercise.
With isokinetic exercises, the “iso-“ prefix refers to “same,” and the suffix “-kinetic” refers to motion, so isokinetic exercise involves performing exercise with a special machine that controls the pace of the exercise throughout the entire range of motion.
Thus, the isokinetic exercise machine will keep the speed and motion of the machine the same throughout the entire movement, no matter how much force you exert.
Isokinetic exercises can be used to target and improve muscular strength and muscular endurance, depending on the muscle groups that you are targeting, the force that you are exerting (the functional resistance), the speed settings that you are using on the isokinetic exercise machine, and the duration/sets that you do.
Isometric vs. Isotonic vs. Isokinetic Exercises
There are three primary types of muscle contractions in fitness training: isometric, isotonic, and isokinetic.
As mentioned, isometric exercises are those that require your muscles to contract without generating movement in your body.
Essentially, an isometric exercise is a static hold. You are still doing muscular work, but no joint movement is occurring.
Examples of isometric exercises include forearm planks, high planks, wall sits, and holding the lower position of a push-up with your chest hovering just over the ground.
Although most people are unfamiliar with the technical term “isotonic,“ the majority of the strength training exercises you typically perform are considered isotonic exercises.
Isotonic exercises are those in which the resistance remains constant, so the amount of tension in the muscle remains the same while the muscle shortens (referred to as a concentric muscle contraction) and lengthens (eccentric contraction) throughout the range of motion.
Pretty much all of the standard resistance training exercises you do—such as curls, squats, deadlifts, and triceps extensions—are isotonic exercises.
As mentioned, with isokinetic exercises, the speed of the movement stays the same, no matter how much force is exerted.
Benefits of Isokinetic Exercise
Although isokinetic exercises can certainly sound complicated and they require the use of specialized equipment, there are several benefits of isokinetic exercise, including the following:
The primary setting in which isokinetic exercise is performed is in physical or occupational therapy to rehab and recover from musculoskeletal injuries, surgeries, or functional musculoskeletal impairments after strokes or other medical conditions.
For example, one study found that isokinetic exercises were effective at increasing the strength in the knee flexors and extensors (quads and hamstrings) and correcting muscle imbalances in professional soccer players.
The reason that isokinetic exercises are particularly beneficial in rehabilitation settings after musculoskeletal injuries is that they essentially have a built-in injury-risk-reduction safety net.
No matter how much force the user exerts on the isokinetic exercise machine, the machine will not move at a faster speed, which can reduce the risk of any kind of muscle tears or tendon strains.
The physical therapist or occupational therapist overseeing the treatment can set specific limits for speed and resistance on the machine that the user cannot accidentally override, allowing for very controlled, low-risk, and safe movement.
Reducing Osteoarthritis Pain
Studies have shown that isokinetic exercises can reduce the pain associated with osteoarthritis of the knees.
Isokinetic Exercise Examples
Isokinetic exercises are not very common outside of physical therapy, occupational therapy, or other rehabilitation settings.
Most people who scan their local gym for isokinetic exercise examples are going to come up short because isokinetic exercises usually involve the use of specialized, and very expensive exercise equipment.
A specialized isokinetic exercise machine keeps the speed of the motion constant no matter what force the user is applying throughout the range of motion by way of electronically-controlled hydraulic mechanisms.
With that said, with deliberate attention to the speed at which you are moving, it’s possible to perform isokinetic exercises in your own training with certain pieces of standard exercise equipment.
Consider the following examples:
#1: Exercise Bike
An exercise bike, such as a stationary bike or a spin bike (indoor cycle), can be used for isokinetic exercise if you pedal at a constant rate or cadence.
Throughout the pedal stroke, your muscles are exerting different levels of force depending on the joint angles, but the speed of your motion remains constant.
For example, studies that have used EMG to measure muscle activation have found that the rectus femoris, the primary quad muscle that runs down the center of the thigh, is most active during the first quarter and last quarter of the cycling pedal stroke.
The quads are biarticular muscles because they help flex the hip and extend the knee.
The cycling pedal stroke begins when the foot is at the top position and ends when the foot returns to the same position.
Therefore, the first quarter involves the initial crank of the pedal towards the floor until the foot is as far forward as it will get (and is halfway to the lowest position down by the floor).
The last quarter of the cycling stroke takes your foot from the position that it gets behind you back up to the top.
During the downward phase of the pedal stroke, the quadriceps (particularly the rectus femoris muscle) contract to straighten the knee, and then at the end of the pedal stroke, the quadriceps contract to help flex the hip.
However, during the middle portion of the cycling pedal stroke, the quadriceps are not all that active because the knee is flexing passively (so no eccentric quad contraction is required), and the hip is extending.
Therefore, the amount of force that your quads are exerting throughout the cycling pedal stroke is not constant, but the speed at which your legs are moving, and your quads are contracting are constant. This makes it an isokinetic movement.
#2: Arm Ergometer
An arm ergometer is essentially an exercise bike for your arms, so the same principles can apply here to perform isokinetic exercises.
Walking on a treadmill can also be an example of an isokinetic exercise, although not quite as perfect as cycling on an exercise bike.
If you walk at a constant speed, your muscles are contracting at the same speed throughout the range of motion.
One example of isokinetic exercise machines is dynamometers, which are specialized exercise equipment that is able to measure force output during movement that occurs at a controlled and constant speed.
These tools are often used in exercise testing and research, as well as in rehabilitation settings, to assess strength and measure progress.
#5: Manual Rep Timing
Theoretically, it’s possible to turn most standard strength training exercises with resistance bands into an isokinetic exercise by deliberately, manually controlling the speed and rhythm of your reps.
Although trying to do this yourself without the aid of a specialized exercise machine will likely be less precise, you can somewhat replicate the experience of an isokinetic exercise.
You would need to move at a constant speed throughout the entire range of motion for the exercise.
Because you are using resistance bands, the amount of resistance will change throughout the range of motion based on the degree of stretch in the band due to the distance from the end of the band to the point of attachment.
In most cases, working with a physical therapist or occupational therapist will be the best route for integrating isokinetic exercises into your workout routine, but you can certainly try to implement some isokinetic training on your own using an exercise bike or trying to control the speed of your strength training exercises.
For a total body workout using resistance bands, check out our guide here.