Isometric exercises help build strength in a joint's support structure with minimal risk of injury. These exercises are usually used with people who are recovering from an injury. If you have no prior injury or joint pain, but you want to strengthen your tendons and ligaments to prevent a future injury, you will probably have better success with a traditional resistance-training program that involves a wide range of motion.
Identification
Tendons connect your muscles to your skeleton and ligaments hold your joints in place. In general, when you contract a muscle, you shorten the muscle, which changes the angles of your bones. If you contract your biceps, your lower arm moves closer to the upper arm. With an isometric muscle contraction, however, there is no change in joint angle because you exert force against an immovable object. This helps strengthen the muscle at the precise angle of contraction.
Benefits
Isometric exercises can help people with arthritis or those recovering from a joint injury or surgery because the lack of joint movement makes it unlikely to injure the joint further. This type of muscle contraction allows you to strengthen the muscles, tendons and ligaments when traditional exercises like running or weightlifting would put too much stress on a fragile joint.
Drawbacks
According to the American Council on Exercise, isometric exercises are very specific to the exact angle of the exercise. In other words, if you push your foot against a doorframe to strengthen the tendons, ligaments and muscles of the ankle, you will only strengthen them in that exact straight-forward position. The structures around the side of the ankle won't get any benefit at all.
Exercises
Isometric exercises don't require any special equipment, and you can use them on almost any affected joint. To work your ankles, sit facing a wall with the soles of your feet flat against the wall and press your feet forward. Similarly, to work your leg extensors -- quadriceps, hamstrings and glutes -- lie on your back on the floor with your knees bent and the soles of your feet flat against the wall and press your feet into the wall. You can follow the same concept with almost any joint.
Caution
Since isometrics only work the exact angle of contraction, these exercises are most effective when you do them at a variety of angles. If you are recovering from a sprain, broken bone or ligament repair surgery, your physician and a physical therapist will be able to prescribe a series of exercises that meet your specific needs.
Progression
Once your joint becomes more stable, you will probably move on from isometrics to traditional exercises that involve joint movement. Depending on the nature of your injury, you might simply work on flexing and extending the joint, or using resistance bands to increase the work for the muscles. As the joint gets stronger and your doctor approves, you can add more resistance and impact to your exercise until you return to a full range of motion.
References
- "ACE Group Fitness Instructor Manual;" American Council on Exercise; 2006
- Associated Therapeutics: Possible Treatments
- StateUniversity.com: Exercise
- "Fitness Professionals' Guide to Muscculoskeletal Anatomy and Human Movement;" Lawrence Golding; 2003
