Isotonic movement is a type of muscle contraction. The term “isotonic” comes from ancient Greek and roughly translates into “same tension” or “same tone.”
“This means isotonic exercise keeps the muscles at the same tension throughout the movement,” explains Jonathan Sabar, ACE, NCSF, ISSA, a certified trainer and owner of Defy! Fitness in Broomfield, Colorado. “Most exercises we think of for working out are isotonic, moving your body or an external weight through a range of motion deliberately.”
Most exercise regimens include isotonic exercises. You’re probably already familiar with many of them, such as:
- bench presses
Isotonic exercises differ from isometric, or “same length,” exercises. In isometric exercises, your muscles work against a force without changing length. They also differ from isokinetic, or “same speed,” exercise, in which your rate of movement is constant. Isokinetic exercise “requires specialized equipment to keep the load moving at a constant rate, regardless of the force applied,” says Sabar.
Isotonic exercises are popular because many of them don’t require special equipment or anything you can’t find in a typical gym. Additionally, many isotonic exercises are natural and intuitive for most people to do, meaning they translate well into movements that you perform daily outside of the gym. They also work the targeted joint’s entire range of motion.
While isotonic exercises tend to be intuitive, it’s important to develop proper technique. Many people never learn the finer points of completing these exercises. “Pushups are an awesome exercise nobody ever teaches,” says Sabar. “They just say, ‘Drop and give me 10.’”
To get the most out of your exercise regimen, read Sabar’s tips for perfecting your squats and pushups below.
To help you perform squats properly, Sabar offers the following advice:
- Make sure your knees are tracking, or in line while bending, with your third/fourth toes. If your knees tend to buckle inward, rotate your feet outward slightly.
- Don’t flatten your back or exaggerate your back arch. Use your glutes, abs, back, and hip flexors to keep your ribcage and your back in a neutral curve.
- Keep your weight distributed throughout your entire foot during the squat. Don’t rock forward to the ball of your foot.
- Expect the range of motion of a full squat to bottom out when the crease of your hip is at or slightly below the top of your knee.
- Initiate the drive back up from your hips, not your knees. Start the movement by squeezing your glutes.
Sabar offers the following tips to help you perfect your pushup technique:
- Start out in a plank position. Place your hands on the floor with your fingertips pointed forward and your toes on the floor with your feet about hip-width apart.
- Twist your hands outward slightly, as though you’re trying to unscrew the lid of a jar with your left hand while tightening one with your right hand. This puts your shoulders into external rotation.
- Tighten your abdominal muscles and pull your hips slightly toward your ribs, while squeezing your glutes. This flattens your back and keeps your core stable.
- Squeeze your quads as though you’re trying to pull your kneecaps up to your thighs.
- Bend at your elbows to lower toward the ground, while maintaining the external rotation of your shoulders. This should put your upper arms close to 45 degrees out from your body.
- Stay tight through your core and shoulders as you lower your chest almost to the floor. Your chest, not your chin, should reach the floor.
- Your shoulders should be lower than your elbows as you press back up to your starting position.
- Be sure to keep your neck neutral, or in line with your spine, throughout each push-up.
Are you working toward performing full military pushups on the floor? Sabar suggests starting with “negatives,” or incline pushups. “Lower yourself slowly and with a perfect plank,” he says. “Then get back to the start position by peeling off of the floor or coming to your knees.”
Isotonic exercises are a great addition to your workout. Many isotonic movements, such as squats and pushups, seem intuitive, but it’s important to practice proper technique. Follow Sabar’s tips for safe and effective squats and pushups. Then consider asking a professional fitness trainer to help you fine-tune other isotonic movements in your fitness routine.