Isotonic exercise is a type of physical activity that involves moving a joint through a range of motion while the muscle attached to the joint contracts and shortens. In this type of exercise, the tension on the muscle remains constant throughout the entire movement, resulting in a consistent load on the muscle. Unlike isometric exercise, where the muscle contracts without any movement, isotonic exercise involves movement of the muscle.

Isotonic exercise is commonly used in strength training and physical therapy to increase muscle strength, endurance, and flexibility. It is also an effective way to improve cardiovascular fitness and overall health. Some common examples of isotonic exercises include push-ups, pull-ups, squats, lunges, and bicep curls. In a study released by the MDPI, it’s proven that isotonic and isometric exercise can improve the strength and flexibility of the hamstrings. 

Benefits of Isotonic Exercise

  1. Builds muscle strength and endurance: Isotonic exercise helps to increase muscle strength and endurance by placing a constant load on the muscle throughout the entire movement.
  2. Improves flexibility: Isotonic exercise also helps to improve flexibility by moving the joint through a range of motion.
  3. Promotes cardiovascular fitness: Isotonic exercise can be an effective way to improve cardiovascular fitness by increasing heart rate and improving circulation.
  4. Enhances bone density: Isotonic exercise is also beneficial for bone health, as it can help to increase bone density and reduce the risk of osteoporosis.
  5. Aids in weight loss: Isotonic exercise can also be an effective way to lose weight, as it burns calories and increases metabolism.

→ Learn more about isotonic exercise in our certified CEU Course for Athletic Trainers and Physical Therapists

Types of Isotonic Exercise

There are two types of isotonic exercise: concentric and eccentric.

  1. Concentric: In concentric isotonic exercise, the muscle shortens while it contracts. For example, when you do a bicep curl, the bicep muscle shortens as it contracts to lift the weight.
  2. Eccentric: In eccentric isotonic exercise, the muscle lengthens while it contracts. For example, when you lower the weight during a bicep curl, the bicep muscle lengthens as it contracts to control the movement.

Both types of isotonic exercise are important for building muscle strength and endurance, and they can be combined in a single exercise for maximum benefit.


As with any physical activity, it is important to take precautions when performing isotonic exercise to avoid injury. It is important to warm up before exercise and to use proper form and technique. It is also important to start with a light weight and gradually increase the weight as your strength and endurance improve.

Isotonic exercise is a safe and effective way to improve muscle strength, endurance, flexibility, cardiovascular fitness, and overall health. By incorporating isotonic exercise into your fitness routine, you can improve your physical fitness and reduce the risk of injury and disease. Whether you are a beginner or an experienced athlete, isotonic exercise can help you achieve your fitness goals and live a healthy, active life.

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