What is isotonic exercise
Isotonic exercise also called dynamic exercise, is an exercise in which the tension applied to muscle remains unchanged while the length of opposing muscles changes such as when a contracting muscle shortens against a constant load, for example when lifting weights for the conditioning of a muscle group. Isotonic comes from the Greek “iso-“, equal + “tonos”, tone = maintaining equal (muscle) tone. The muscle maintains equal tone while shortening in isotonic exercise. In contrast, isometric exercise also called static exercise, is when muscular contractions occur without movement of the involved parts of the body.
Isotonic exercises have two types of contractions:
- Concentric contractions: when your muscle shortens as you overcome the force of a weight
- Eccentric contractions: when your muscle lengthens while being opposed by the force of a weight
For instance, when you are performing a bicep curl as you lift the weight up towards your shoulder your biceps perform a concentric contraction. When your bring the weight down, the contraction becomes eccentric. Your muscles are resisting the load of the weight throughout the whole range of motion.
In a concentric contraction the muscular force overcomes the resistance whereas in an eccentric contraction the resistance is too great to be overcome by muscular force. This leads to a lengthening of the muscle being subjected to the load. An example of an eccentric contraction would be trying to do bicep curls with a weight that is too heavy to get off the ground. Almost all bodybuilding exercises done with weights execute isotonic movements, primarily of the concentric kind.
Examples of isotonic exercises
- Squats: Stand up tall with a dumbbell in each of your hands. Stick your bum out behind you while bending your knees. Lower yourself down as far as you can while, at the same time, keeping your chest at the same angle as your shins. Push up through your heels as well as squeeze your glutes to come back up.
- Straight-leg deadlifts: Stand straight while you hold a dumbbell in each of your hands in front of your thighs. Lean forward, stick your butt out behind you and contract your core in order to keep your back flat. Lower yourself down as far as possible. Don’t bend your knees. Squeeze your glutes to come back up.
- Push-ups: Starting on your hands and knees (or toes) in a plank position, slowly lower down as far as you can go. Bend your elbows out to the sides. Push back up at the same pace. You can put a weight plate on your back to increase the intensity.
Isotonic exercises are great for maintaining your overall fitness. These usually performed using weights and is the action of your muscles resisting the load of the weight which makes these exercise so effective. The benefits of isotonic exercises include reduced body fat and enhanced muscle endurance.
Most forms of movement contain both types of exercise, although some are mostly isotonic (jogging, cross-country skiing, and swimming) and others isometric (weightlifting and speed skiing). Isotonic exercise causes a volume overload of the heart and an increase in oxygen consumption, heart rate, stroke volume, cardiac output, and systolic blood pressure. Owing to the decrease in peripheral resistance, the diastolic blood pressure may fall during isotonic exercise. Isometric exercise, which causes mainly pressure overload, induces a sudden increase of blood pressure, whereas the increase in oxygen consumption and cardiac output is limited. The load in isometric exercise may be difficult to control, which makes isometric exercise unsuitable in some young patients with congenital heart disease 1.
Isotonic and isometric exercise
Isotonic exercise is recognized by rhythmic muscular contractions with changes in muscle length, using a relatively small force. Isometric exercise is recognized by a relatively large force with little or no change in muscle length.
Isometric exercises are contractions of a particular muscle or group of muscles. During isometric exercises, the muscle doesn’t noticeably change length and the affected joint doesn’t move. Isometric exercises help maintain strength. They can also build strength, but not effectively.
Because isometric exercises are done in one position without movement, they’ll improve strength in only one particular position. You’d have to do various isometric exercises through your limb’s whole range of motion to improve muscle strength across the range. In addition, since isometric exercises are done in a static position, they won’t help improve speed or athletic performance. They can be useful, however, in enhancing stabilization — maintaining the position of the affected area — since muscles often contract isometrically to aid in stabilization.
Isometric exercises may be helpful to someone who has an injury, which could make movement painful. For instance, if you injure your rotator cuff, your doctor or physical therapist might initially recommend isometric exercises involving the group of muscles that helps stabilize the shoulder to maintain shoulder strength during recovery.
Isometric training may also be helpful to someone who has arthritis, which could be aggravated by using muscles to move a joint through the full range of motion. As people with arthritis perform isometric exercises and their strength improves, they may progress to other types of strength training. Strength training may help reduce pain and improve physical function.
Studies have shown that isometric exercises may also help lower your blood pressure. However, if you have high blood pressure, exercise at a lower level of intensity. Exercising at a higher level of intensity can cause a dramatic increase in your blood pressure during the activity.
Check with your doctor before beginning isometric exercises if you have high blood pressure or any heart problems. Avoid holding your breath and straining during any weight training exercise, as this may cause a dangerous rise in blood pressure.
Isotonic exercise benefits
Isotonic exercises help you to get into shape and to maintain a level of fitness. It is, however, possible to gain mass from constant isotonic exercises over a longer period of time.
Regular exercise strengthens and tones your brain just as it does your body. Research shows that sitting around too much increases your risk of chronic disease which may well lead to an early death. In fact people who exercise regularly live on average 7 years longer than those who are physically inactive. It also shows that as little as 15 minutes of physical activity a day can reduce your risk significantly and improve your quality of life.
Exercise can also help you maintain your weight loss. Studies show that people who lose weight and keep it off over the long term get regular physical activity.
Although the research isn’t fully conclusive, more studies are showing how essential exercise is for keeping your brain fit. And the best news? You can actually build a stronger brain through exercise.
These are just a few of the remarkable findings that might motivate you to either recommit to your fitness regimen or get started today. Staying active can help you:
- Enhanced muscle strength as well as size
- Improving strength throughout the full range of motion (ROM)
- Enhanced muscle endurance
- Increasing mass by making use of heavy weights as well as increasing resistance over time
- Enhanced range of motion in functional movements
- Training your body in movements need for daily activities
- Improved bone density
- Increasing cardiovascular health
- Lowering body fat
- Increasing fat-free mass
- Assisting with maintaining your metabolism as you age.
- Feel better. Walking and other moderate aerobic exercise has been shown to help stabilize your mood and help with depressive symptoms. Studies have also found that regular exercise helps people better control their stress and regulate their emotions.
- Enhance learning. While scientists don’t fully understand how physical activity contributes to learning, they’re discovering that it works. In one study, when teachers added exercise routines to math lessons — called motor-enriched learning — math scores improved faster for the exercisers than for the kids who didn’t exercise during the lesson. Other studies have found that exercise helps improve reading comprehension, too.
- Sharpen memory. Although brain size decreases as you age, research has shown that exercise can actually help reverse that — at any age. One study found that physical activity helped participants build measurable increases in the hippocampus, the part of the brain that enables you to create and store memories. Another study showed that people with better cardiovascular fitness as young adults had better memory, motor skills and executive function 25 years later as middle-aged adults.
- Improve vision. When you exercise, you’re stimulating the neurons in the part of your brain that helps you sort out and understand what you’re seeing. Research has found evidence that your visual system becomes more sensitive during exercise and may actually enhance visual learning.
- Keep and improve your strength so you can stay independent.
- Have more energy to do the things you want to do and reduce fatigue.
- Improve your balance and lower risk of falls and injuries from falls.
- Manage and prevent some diseases like arthritis, heart disease, stroke, type 2 diabetes, osteoporosis, and 8 types of cancer, including breast and colon cancer.
- Sleep better at home.
- Reduce levels of stress and anxiety.
- Reach or maintain a healthy weight and reduce risk of excessive weight gain.
- Control your blood pressure.
- Possibly improve or maintain some aspects of cognitive function, such as your ability to shift quickly between tasks or plan an activity and ignore irrelevant information.
- Perk up your mood and reduce feelings of depression.
You don’t need to become a fitness fiend to reap benefits. In many studies, just walking briskly for 30 to 60 minutes, three to five times a week, contributed to measurable brain improvements.
Evidence does suggest that resistance training and aerobic exercise — walking, running, biking, swimming — may help your brain more than stretching exercises do. In one study, older adults with mild cognitive impairment who lifted weights two to three times a week improved muscle tone and cognitive function.
Your brain is amazing. Billions of nerve cells work together in harmony to coordinate every second of your life: your movements, behavior, thoughts, memories and emotions. So take your brain to the gym to maximize whole-body health.
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