What is Isokinetic Exercise?
Isokinetic exercises involve the contraction and extension of muscles within a prescribed range of motion at a constant angular velocity. This type of activity can be observed when an individual holds onto something stationary, like the backrest on an exercise cycle, and moves their legs against it at a set speed (isokinetic).
Another example could be doing a shoulder press using free weights. The amount of weight to be lifted is controlled by the individual during this activity; it’s much less than if they were pushing or pressing into something that would move (such as making someone who was resisting them).
Comparing these two examples shows how strenuous isokinetic activities are compared to isotonic (regular) exercise involving uncontrolled movement.
Isokinetic activity is a functional exercise because it trains muscles to work together to complete a particular task or movement. This is effective during rehabilitation after an injury to strengthen muscles and joints and achieve maximal strength for sports-related activities.
Isokinetic resistance training using hydraulic machines has established itself as a reliable alternative when free weights are not practical or available. They are generally much safer because of the reduced risk of dropping weights and injuring people nearby.
To understand “true” isotonic, consider this: If you were to hold onto something stationary. At the same time, if your friend tries to push or pull on you with constant speed, you will be performing an isometric exercise.
This would be the equivalent of isotonic with external resistance. No matter how substantial your friend is, you wouldn’t move because something else (the stationary object) held you back. However, if you let go of the thing and try to keep your body still while your friend pushes or pulls on it, you are now performing an isotonic exercise.
Isokinetic machines use hydraulic cylinders with pistons that create a “force-velocity” relationship where maximum tension can be generated during complete muscle extension at very high speeds while allowing slow, controlled movements in full contraction at meager rates, easing joint pain and rehab. These work by adjusting automatically, so equal effort against equal resistance is the rule.
Resistance in an isokinetic machine can be adjusted to 10% and 90% of a person’s maximum strength (determined by how much weight they can lift on one repetition) while exercising through some or all of the full range of motion.
Because these machines automatically adjust resistance, none of the issues related to changing loads affect traditional weight training. Additionally, suppose the user gets stronger over time (or their physical condition improves). In that case, new resistance settings could be programmed into it, meaning they wouldn’t have to purchase new equipment so often.
Differences between Isokinetic Resistance Exercise Machines and Related Terms:
Table of Contents
1) Isokinetics – Exercises “at a certain speed” using constant loads.
2) Isometrics – Exercises “without movement” using constant loads.
3) Eccentrics—Exercises with a variable load. For example, during the lowering phase in free weights, gravity is the load (which may be greater than the concentric force provided by muscles).
4) Concentric— Muscle shortens to lift an external resistance (such as when moving up in a curl). Eccentric—Muscle lengthens while under tension (lowering or coming down phase of movement in circles). Isometric Muscle length stays the same throughout contraction (meaning no visible change in muscle size occurs; it occurs where you hold weight in one spot, like when pushing against an immovable object).
Isotonic – Variable loads produced by the body or a machine change intensity throughout the exercise.
5) Isokinetic – Constant loads, but strength changes throughout the range of motion.
6) Dynamic constant external resistance – Variable resistances as you move through different parts of your range of motion. This type of equipment is also called flywheel equipment.
7) Dynamic variable internal resistance— Resistance varies as you move through different parts of your range of motion due to inertia and gravity acting against moving components within the machine itself. This type of equipment is also called plate-loaded equipment because plates slide on a carriage or track to provide more or less weight depending on where you are in the range of motion.
Benefits of isokinetic exercise.
Isokinetic machines provide many benefits compared to traditional weight-lifting programs.
1) Precise control of the exercise intensity. The strength-training power can be set precisely and reproducibly within and between training sessions with isokinetic machines. You can use a specific percentage of your maximum strength or lift several times.
2) Full range-of-motion movement. Because the movement speed is constant, you move through your full natural range of motion during each exercise.
3) Full muscular recruitment. Because you work against variable resistance that increases as the muscles lengthen during an exercise, all major muscle groups are fully engaged throughout each exercise.
4) Less joint stress. Since heavy weights aren’t lifted, standard pressure is reduced for people with injuries or otherwise sore from weight lifting. Also, since body positioning doesn’t change during an exercise, joint stress is reduced compared to traditional weight training.
5) Muscle training and cardiovascular conditioning in one workout.
6) Less time is needed to get a complete workout. An isokinetic exercise can do twice the work in half because of the variable resistance that builds during each repetition. That’s how you get better results in less time!