If you want to build muscle without lifting a finger, isometric exercises are for you. Isometric exercises strengthen muscles without movement of the joints or lengthening of the muscles. Considerable power and strength can be produced inside the muscle, even though work is not actually completed. Isometric exercises are performed against considerable resistance such as an immovable object. If performed progressively, changes in strength can occur.
There are many advantages to isometric exercise. You can do isometrics anywhere since you do not need special equipment. You can increase your muscular strength without risking joint soreness. In the 2003 study in "Journal of Applied Physiology" by Gregory R. Adams, et. al, there may be muscle carryover that effects strengthening other parts of the range of motion. In addition, isometrics are an exceptional means of developing strength if you are incapable of completing more difficult exercises. It can help to slow muscular atrophy process if you are de-conditioned from an illness or disability. Isometric exercises produce a muscle pumping process that can help to decrease swelling and foster circulation.
There are disadvantages to isometric exercise. First, since there is no work actually being performed, muscular strength may be restricted to the joint angle position of the exercise. According to Steven G. Lesh in the book, "Clinical Orthopedics for the Physical Therapist Assistant," work is measured as force x distance: with no movement, the work result is zero." Because there is not an eccentric contraction, isometric exercise cannot extensively progress muscular endurance the way that traditional exercises do.
Frequency and Duration
Isometric program frequency is determined by your fitness goals. If your goal is to rehabilitate from an injury or illness, the training frequency is generally five to seven days per week. If your goal is to build both strength and muscular endurance, a training frequency of three days per week has shown to create ample gains. With isometric exercises, the idea is to statically hold a muscular contraction for a set amount of time at a specific torque. Generally, you would tighten the muscle without moving the nearby joint for five to 10 seconds for 10 to 15 repetitions. Isometric exercises should be performed slowly and gently. Aim for an isometric training program duration of at least four weeks.
It is important to rotate your isometric exercise routine so as not to over work particular muscle groups. While isometric exercises are generally gentler than traditional strength training exercises, it is still possible to over-train specific muscles and supportive structures. An example of an isometric training program to avoid over-training would be to work the legs and abdominals on Mondays and Fridays; the chest, shoulders and triceps on Tuesdays and Saturdays; and the back and biceps on Thursday and Sunday. Also, if performed against considerable resistance isometric exercises have the potential to raise blood pressure. If you have a prior history of cardiovascular disease or stroke, speak to your healthcare professional prior to beginning an exercise program involving isometric exercises.
- Clinical Orthopedics for the Physical Therapist Assistant; Steven G. Lesh
- Journal of Applied Physiology; Skeletal muscle hypertrophy in response to isometric, lengthening, and shortening training bouts of equivalent duration ; Gregory R. Adams, et. al; 2004.
- MedlinePlus: Isometric exercise
- Physical Therapy; Isometric, Isotonic, and Isokinetic Torque Variations in Four Muscle Groups Through a Range of Joint Motion; Joseph J Knapik, et. al; 1983.
- Comstock Images/Comstock/Getty Images