When you move a resistance through a range of motion, it is known as a dynamic movement. The contraction involved with this is called isotonic, which means there was a lengthening and shortening of a muscle. You can clearly see this by doing a biceps curl. While lifting the weight, notice how your bicep starts out long and then shortens. Isometric exercises, which are also known as static exercises, do not involve a lengthening and shortening of a muscle. Instead, a contraction is held for an extended period of time. The best isometric exercises target all of your major muscle groups. It is not advised to do isometrics if you have high blood pressure.
Chest Squeeze
The chest squeeze works the two-part pectoralis muscles. This exercise is performed with the hands and with an exercise ball. To use your hands, sit or stand with your feet shoulder-width apart and place your hands together in front of your body. Squeeze forcefully until you become fatigued. To place emphasis on different areas of your chest, move your hands in closer to your body or farther away. To use the exercise ball, wrap your arms around it in the center and squeeze as hard as possible.
Wall Squats
Wall squats isometrically work the quadriceps, which are the front thigh muscles. To do these, back up into a wall and slide down as you walk your feet forward. When your thighs parallel the floor and your lower legs parallel the wall, hold the contraction.
Butt Bridges
Butt bridges target the gluteus maximus, hamstrings and lower back muscles at the same time. To do these, lie on your back and prop your heels up on a chair, bench or stability ball. Lift your hips in the air, bend your knees slightly and contract your glutes. Hold until you feel fatigued.
Pull-up Holds
Pull-up holds work the latissimus dorsi, rhomboids and biceps. The lats and rhomboids are middle and upper-back muscles. To do these, jump up and grab a pull-up bar with an overhand, shoulder-width grip. Steadily pull yourself up until your chin is above the bar, and hold this position until you are fatigued. When doing these, do not rest your chin on the bar.
Chaturanga
Chaturanga dandasana is a yoga pose that isometrically works the triceps. Start this exercise from a lying position on your stomach with your feet together behind you. After placing your hands shoulder-width apart, push your body straight up until your arms are fully extended. Keeping your core tight and back straight, lower your body until your upper arms parallel the floor and hold this position until you become fatigued. When doing the chaturanga, keep your arms close to your body.
V-sit
The v-sit works the abdominal muscles from a face-up position. While sitting on the floor with your knees bent and and feet flat, lean back so your back is at a 45-degree angle. Carefully lift your legs straight into the air so your body makes a "V" shape and balance on your butt. Hold this position for as long as possible and feel your abs contracting. When doing this exercise, keep your back straight and extend your arms out by your legs.
