Isotonic stretches incorporate movement, encouraging greater range of motion.
Also known as dynamic stretches, isotonic stretches are stretches that incorporate movement. Many resistance exercises naturally include isotonic stretching elements, such as lunges and curls. Isotonic stretches encourage mobility and range of motion in your limbs and joints, and help your muscles warm-up prior to a workout as they encourage blood flow.
Isotonic Vs. Isometric
Isotonic exercises combine a mix of lengthening and shortening of the muscle fibers in one exercise. Often, these types of stretches will involve opening and closing joints, in some cases, in tandem with resistance training, as in the case of squats or lunges. Isometric exercises, in turn, do not change the length of your muscles during the exercise, such as plank position, where your muscles are strengthened while staying the same length throughout. Isotonic exercises build mobility as well as muscle tone while stretching the muscle, making it a multi-purpose exercise.
As a warm-up, isotonic exercises that mimic your cardio or resistance training activity are ideal. For example, if you are about to embark on a long-distance run, dynamic lower body exercises such as leg swings and butt kicks are well-suited to warming up and stretching your lower body muscles. Similarly, if you are about to play tennis, or engage in an upper body exercise, swinging your arms across your chest, or doing arm circles will increase blood flow while stretching your muscles and improving overall mobility in your upper body area.
How Long To Stretch
Unlike static stretches, where you hold the position for 30 to 60 seconds, isotonic stretching generally requires up to 12 swings before you reach your maximum stretching potential for an isotonic exercise. Repeating the movement for more than one set will make your muscles feel warmer, increasing blood flow and encouraging greater muscle elongation. However, if you feel tired or your muscles burn after a lower number of repetitions or sets, stop your exercise to reduce the risk of injury.
Don't Push Too Far
Because it doesn't feel like a static stretch - where you can feel the stretch for an extended period - you might be tempted to extend an isotonic stretch beyond your comfort level. However, to prevent injury and to build up muscle flexibility, begin with smaller movements and build towards the larger ones - where larger muscles or muscle groups are activated. Working at 75 percent of your maximum stretching ability is recommended, so you do not overwork your muscles. Start slowly, paying close attention to form before increasing speed or number of repetitions. For example, with arm circles, start with smaller circles, ensuring you have the correct form before increasing the speed and size of the circles.