Isometric exercise is a form of resistance training in which the participant uses the muscles of the body to exert a force either against an immovable object or to hold the muscle in a fixed position for a set duration of time. In this type of exercise, the muscle is contracted but does not change length during the exertion of force. Additionally the joint most closely associated with the effort remains static throughout the exercise.
Although isometric exercises may result in a great deal of benefit to the individual, there are some precautions that should be noted. Specifically those with high blood pressure should not engage in this type of activity because isometric exercises cause a spike in blood pressure.
Although the blood pressure typically returns to normal rather quickly once the muscle is relaxed, the spike in blood pressure can be dangerous to those who already suffer from elevated blood pressure. If you suffer from high blood pressure but you really want to engage in isometric exercises, please consult with your doctor for tips on how to lower blood pressure first.
Other considerations when performing isometric exercises include the duration of time each action is held, as well as the angle of the joint when the action is formed. The duration of time an isometric exercise is performed is comparable to the number of repetitions performed in other types of strength training exercises.
For strength training purposes, a duration of 3-5 seconds per exercise is optimal. However, when body weight is used as resistance, longer durations of more than 10 seconds are required. In terms of joint angle, it is important to note that the muscle will only gain strength for the joint angle at which the exercise is performed. Individuals who want to gain strength through the entire full range of motion of the muscle should consider training at intervals of ten to 30 degrees. However, this can be rather time consuming.
The following are examples of different forms of isometric exercises that help to improve the strength of muscles such as the abdominals, shoulders, quadriceps and calves.
The Plank – for abdominal improvement.
The plank engages a lot of muscles; in addition to strenghtening your abs, you’ll also condition your back. The is one of the best core exercises that exists.
- Start out by lying flat on the floor.
- Slowly raise the body so you are resting on your toes and forearms.
- Keep the back flat and the abdominal muscles taut.
- Hold the position for 10-30 seconds.
- Repeat the exercise 2-3 times.
When this becomes easy, curl your toes under your feet to make it more difficult. You can also extend one arm forward for another difficult variation.
Isometric Shoulder Raises – for shoulder improvement.
- Stand with the feet shoulder-width apart and the knees slightly bent.
- Grasp a dumbbell in each hand and raise the weight out towards your side until it is at shoulder length and your arm is parallel to the ground.
- Hold the weight in this position for 10-30 seconds.
- Repeat the exercise 2-3 times.
If this is too difficult, try lifting with just one arm at a time, alternating, until you can handle both weights at a time. If you don’t have a dumbell, you can also use bands or tubing the same way.
Isometric Squats – for quadriceps improvement.
- Stand with your feet shoulder-width apart and your back firmly against a wall.
- Slowly slide down the wall until your thighs are parallel to the floor.
- If necessary, move your feet away from the wall to ensure your knees do not extend past your toes.
- Hold the position for 10-30 seconds.
- Repeat the exercise 2-3 times.
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Isometric Calf Raises – for calf improvement.
- Stand next to a wall on one foot and touch the wall lightly for balance, if necessary, but do not allow yourself to rest against the wall.
- Rise up onto your toes.
- Hold the position for 10-30 seconds.
- Switch feet and repeat the exercise for the other calf.
- Repeat the exercise on both calves 2-3 times.
Source: howtodothings.com