Resistance training has undergone plenty of evolution over the years; modern-day gyms carry far more than treadmills and punching bags. That said, when it comes to improving your fitness, all roads lead to Rome eventually.
This applies to the language used to categorize and describe exercise: Closed-chain, open-chain, concentric, eccentric, isometric, isotonic…the list of jargon goes on (and on, and on). Terminology flies fast and furious and easily lead you down a frustrating rabbit hole that may impact your results.
You’ve heard of “isotonic exercise” in passing. Is it something you’re missing out on, or should do more of? Here’s what you need to know. And don’t worry, it’s simpler than it sounds.
Defining Isotonic Exercise (and More)
Phrases like isotonic are meant to characterize how you complete repetitions of an exercise. Along with isometric and isokinetic, these labels often step on each other’s toes. Knowing how they relate to one another, and what aspects of movement they describe, is a great place to start.
Isotonic
Isotonic exercise refers to motion (scientifically regarded as a flexion-extension cycle) at a joint, usually against resistance. This may sound like a clunky way of describing how you normally train — that’s because it is.
Isotonic exercise is the most common form of resistance training. Grab ahold of whatever you’re working with and get to work while the resistance in question is consistently applied to the joint you’re moving.
Isokinetic
Isokinetic means “consistent speed.” No matter how heavy you’re lifting (or moving your body if you’re doing bodyweight training), the pace at which the joint opens and closes remains the same, as does the intensity of the resistance.
Certain plate-loaded exercise machines (such as pendulum-loaded stations) accommodate for this by adjusting the resistance curve so things aren’t too easy at one point or too hard at another. Cables are another example.
Isometric
On the other hand, isometric exercise refers to producing force without moving a joint. Think of a plank or wall sit; it’s difficult and taxing, but you aren’t actually moving in space. You’re using your muscles to maintain a specific posture against gravity (or an external weight) and resist the accumulating fatigue in the process.
When Should You Use Isotonic Exercise
Building muscle and getting strong heavily depend on your ability to perform, progress, and replicate isotonic exercise. Other styles (such as isokinetic or isometric) may help with skill development or other odds and ends of athleticism, but they are more difficult to quantify.
Put simply, isotonic exercises are the meat and potatoes of most training programs. Movement at a steady pace — sometimes with extra resistance — is the recipe for getting jacked, strong, or even flexible in some cases.
Benefits of Isotonic Exercise
Isotonics may not be a silver bullet for health and fitness performance as much as they are the default mechanism of resistance training, but you should still understand the benefits of loaded movement.
More Movement Is Better
Your joints are designed to move; that’s their whole purpose. To facilitate that motion, your muscles have to stretch and contract. That process, known as a flexion-extension cycle, is crucial for developing qualities like hypertrophy, strength, and flexibility.
This idea is widely supported in scientific research, which mostly concludes that training your muscles through their full range of motion is superior to using a partial range, all other factors kept equal. (1)
Note that a partial range of motion isn’t the same thing as an isometric, which refers to motionless tension. Still, the logic holds up; your muscles obey the use-it-or-lose-it law, so your best bet is to train them isotonically most of the time.
You’ll Burn More Calories
Caloric expenditure is essential if you’re trying to manage your weight. You burn calories all day just by moving around, sure, but getting your burn on in the gym is an integral part of the puzzle too.
Burning calories is simple physics; it takes more energy to move than it does to remain still. Therefore, isotonic exercise by its very nature burns more calories than non-moving training like isometrics.
This extra energy burn may not amount to a massive increase in how many calories you burn in total, but it’s worth pointing out. If you want to get your sweat on, you should be moving as much as possible.
Best Isotonic Exercises Per Muscle Group
Since isotonic exercise should be the centerpiece of your training, having a few go-to choices for each muscle group can help you stay on the right track. Note that these lifts are probably ones you’re familiar with already; that’s by design.
Still, if you’re brand new to exercise and are trying to assess the lay of the land, know that these moves all count as isotonic and happen to be darn-good at getting you in shape too.
Chest
As far as your chest goes, nothing beats a strong bench press. The bench press will have a great return on investment for strength and muscle gain. Benching (with a barbell or otherwise) counts as isotonic because you must move your shoulder and elbow joints through their ranges of motion at a consistent pace.
Related: Best Chest Exercises
Bench Press
Lie down on your back on the bench press station with your eyes directly underneath the barbell. Grab the bar at about the width of your shoulders or slightly wider, and then draw it out of the rack so it rests directly above your shoulders.
Brace your body from head to toe and then lower the bar down to your chest; that’s the isotonic part. The bar should touch your sternum. Once you make contact, reverse the motion smoothly and press back to the starting position.
You can perform the free-weight bench press with a barbell, dumbbells, or even kettlebells.
Shoulders
Your shoulders have a lot of range of motion available to them, which opens up a wide array of exercise choices. To hit all three heads of your delts, you’ll want to go for an overhead press that lets you stimulate all that muscle.
Seated Dumbbell Shoulder Press
Rest a pair of dumbbells on your knees while you sit in a low seat; keep your spine in contact with the backrest the entire time. Kick the weights up to shoulder height; your arms should be bent at a 45-degree angle, forearms perpendicular to the floor, with the weights above your shoulders.
[Read More: The Best Shoulder Exercises for Bigger, Stronger Shoulders]
Brace your core and push your feet into the floor. Then, press the dumbbells overhead. As you push, allow your shoulders to rotate naturally and find a comfortable position with your arms locked out overhead.
You can perform shoulder presses while seated or standing, and with a variety of different pieces of equipment.
Back
You can perform isotonic back exercises in both the horizontal and vertical planes of motion. The setup is different, but you work the same muscles.
Barbell Row
A basic free-weight barbell row will provide a lot of bang for your buck on back day. Stand upright with a barbell in your hands at a shoulder-width grip. Then, brace your core and push your hips backward to hinge over until your torso is almost parallel to the floor. You should feel a stretch in your backside and the barbell should be hanging down under your shoulders. That’s your starting position.
From here, draw your elbows back and pull the barbell up and into your belly. Keep your torso rigid and don’t stand up as you row. Once your arms are tucked into the sides of your torso, reverse the motion.
You can perform rows with a barbell or dumbbells, with or without a chest support, or even on a variety of different exercise machines.
[RELATED: Best Barbells]
Legs
When it comes to isotonic exercise for your legs, you’ll generally break up your lower-body training into two distinct halves; squat and hinge training. There are a lot of moving joints in your lower body, so one exercise won’t cover all your bases.
Back Squat
To perform the back squat, grab the bar evenly with both hands about shoulder-width apart. Duck under the bar and pin your shoulder blades back and down and place the barbell on the natural shelf that develops on your back. Brace your core and stand straight up with the barbell, taking 2-3 steps out of the squat rack to find your starting position.
Place your feet in a comfortable stance about hip to shoulder-width apart. Then, you’re ready to squat. Brace your core and take a breath in, then descend by unlocking your knees and hips simultaneously.
Lower yourself downward, as though you were trying to sit down onto a small box between your feet, as low as you comfortably can without losing your balance. Stand back up by flexing your legs and glutes.
You can do squats with just about anything; a barbell provides lots of loading potential, but you can also hold a dumbbell in the goblet position or even head over to the hack squat machine.
Romanian Deadlift
The hinge pattern is almost perfectly represented by the Romanian deadlift. Grab the bar with a grip about shoulder-width apart and assume a foot stance of about hip-width apart with your toes straight ahead (or subtly turned out). This is your starting position.
Maintain even foot pressure as you slowly slide your hips backward, allowing your knees to unlock but not bend substantially. Hinge over until the bar has slid down past your knees or you feel a strong stretch in the back of your legs. Reverse course by contracting your backside to return to a standing position.
You can work with the barbell to do Romanian deadlifts, but dumbbells are just fine for training the hinge pattern isotonically as well.
Arms
When it comes to using isotonic exercises to train your arms, the options are basically endless. However, almost all arm movements fall into two main categories; curls and extensions.
Dumbbell Curl
Stand with a pair of light dumbbells in your hands and your feet under your hips. From here, bend your elbows to curl the weights up toward your chest. As you curl, rotate your wrists so your palms turn and face the ceiling.
Keep your upper arm tucked tightly to your sides and avoid swaying your torso from side to side. You can perform dumbbell curls with both arms simultaneously or alternate which arm works at a time.
You can do curls with dumbbells, a barbell, at a curl machine, or with a cable attachment. All of these options work your biceps muscles in a similar fashion.
Cable Triceps Extension
Note that this movement is also commonly called a pressdown. Stand facing a cable tree with the attachment set around eye level; use a straight or cambered (bent) bar attachment.
From here, pull on the handles and bring your upper arms back and tuck them into the sides of your torso. Then, extend your elbow until your arm points toward the floor. You should feel a strong sensation in your triceps.
Any movement that involves extending your arm against resistance will work your triceps isotonically, but the cable extension is a good starting point. From here, you can move on to more complex movements like skull crushers or dips.
Isotonics Made Easy
The field of exercise science is chock-full of jargon, much of which is useful to coaches or trainers but can spin your head if you’re a layperson who just wants to get in shape. Isotonic exercise is your bread and butter; it’s as simple as moving a joint through space at a consistent speed with a consistent amount of resistance.
Isotonics will generally make up the bulk of any exercise routine, but that doesn’t mean you should neglect other forms of movement as well. Once you fully understand the different types of movement available to you in the gym, you can start focusing on what really matters; making those gains.
References
- Schoenfeld BJ, Grgic J. Effects of range of motion on muscle development during resistance training interventions: A systematic review. SAGE Open Medicine. 2020;8. doi:10.1177/2050312120901559
Featured Image: PeopleImages.com – Yuri A / Shutterstock
