The Science of Isometric Training — Explained!

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Can you build a stronger and more aesthetically appealing physique by not moving? Wild idea, but that’s what isometric training is all about. On the outside, it looks like nothing is happening. However, on the inside, your muscle activation is off the charts.

Isometric training is not as popular as its dynamic counterpart. I mean, an explosive snatch or a powerful bench press obviously looks pretty exciting. Isometric training doesn’t necessarily attract Instagram views or get your gym crush to give second glances. That said, it’s one of the most researched-backed methods you’re missing out on.

What is Isometric Training?

Isometric training involves static muscle contractions without any visible movement at the joints. The muscle length remains constant during these exercises, and the joint angle doesn’t change. Instead of the traditional range of motion seen in dynamic exercises like squats or bicep curls, isometric exercises focus on maintaining a fixed position against an immovable force.

The plank is a classic isometric exercise where the individual holds a push-up position with arms extended and the body straight. The muscles in the core, arms, and legs engage to keep the body stable against gravity’s attempt at sinking your midsection to the floor.

But isometric training is far more useful than just increasing stability. It will get you strong, jacked, and keep your joints happy forever.

Benefits of Isometric Training

Isometric training is often neglected, but it has a host of benefits. Holding static contractions against resistance will activate lots of muscle fibers and stimulate many favorable adaptations.

Hypertrophy

Unlike dynamic exercises, where you are moving against force, isometric exercises involve exerting force against an immovable object or resisting force applied by external resistance. This produces high tension levels, which is what you need for muscle growth.

You technically don’t need the muscles to change length during your isometric training set. In fact, it might even be advantageous to utilize isometrics when a muscle is in a shortened position. Research has shown this can help promote hypertrophy. (1)

During isometric contractions, motor units are recruited, generating tension within the muscle fibers. This tension increases muscle activation, stimulating muscle fibers to adapt and grow over time. While isometric training is often associated with improving static strength and joint stability, research indicates that it can also play a crucial role in hypertrophy. (2)

The key to growing from isometrics is similar to dynamic strength training. You need to train with enough intensity so high levels of motor unit recruitment occur along with sufficient tension imposed on muscle fibers. 

Enhance Your Mind-Muscle Connection

Lifters love feeling their muscles. That burning sensation indicates that we are training what we intend to. It gives us confidence that we are training optimally and, in some cases, can even enhance our muscle growth. Many lifters report a better mind-muscle connection with their stubborn muscles after incorporating isometrics into their workouts.

Isometrics can also be incredibly effective for warming up before a workout. The mind-muscle connection you develop will prepare those muscles to activate in the workout.

Developing Strength

You’re only as strong as your weakest muscles. If you consistently fail your squat in the hole, it’s worth doing isometrics in that position. The same principle applies if you can’t lock out your bench press. Developing isometric strength in that position will be crucial for strengthening the whole exercise. Isometric training also allows you to engage your muscle fibers better and generate more force. 

This also translates to improved athletic performance. Many sports, like rock climbing, martial arts, and gymnastics, involve isometrics, where you must hold muscle contractions for extended durations.

Injury Prevention and Rehab

Isometric training improves muscle fiber activation without overburdening your joints and connective tissues.  The adaptations from isometric training can also increase joint stability and allow you to keep training for strength and hypertrophy while reducing the risk of injury.

From a rehab perspective, isometric training allows you to train your muscles in specific positions that you can tolerate without doing the full range of motion.

Incorporating Isometric Training Into Your Routine

Most people are clueless about how to incorporate isometric training. It can be simpler than you think. Here’s your go-to checklist for your next workout involving isometrics.

Identify Targeted Muscle Groups

Determine the muscle groups you want to focus on. You can use isometric exercises for various muscle groups, including chest, shoulders, back, core, legs, and arms.

Choose the Right Exercises

Select isometric exercises that target your desired muscle groups. Popular examples include planks and wall sits. However, you don’t necessarily need specific exercises. You can simply take an exercise you already planned on doing and do an isometric hold at a specific point in the lift.

Gradual Progression

Start with shorter holds and gradually increase the duration of contractions. Aim for 10-30 seconds initially and work your way up to 60 seconds or more as you gain strength and muscle endurance. You can use additional resistance as you gain more experience. Isometrics can be highly fatiguing, especially when added on top of your current training load.

Add Them Anywhere in Your Workouts:

If you struggle with your mind-muscle connection, isometrics can be a game-changer at the start of the workout. For example, if your knees are always achy during your leg workout and you never seem to feel your quads, it might be worth pausing at the top of a leg extension’s range of motion or doing a set of wall sits as your first exercise. This recruits your quads and reduces the stress on your knees, giving you a more effective and joint-friendly workout.

However, saving them for the end of your workout can be the way to go if you want a brutal finisher. For example, after you’ve already destroyed your quads on leg day, you can finish with an isometric split squat or a wall sit to failure.

Combine with Dynamic Exercises

Combine isometric training with dynamic exercises for optimal results. A common example of this is to pause at the most challenging point of a dynamic exercise. For example, you can add a four-second pause at the bottom of each squat. This is the most difficult portion of the squat, where muscle activation and muscle tension are highest due to the difficulty and stretched position.

For other exercises where the top is harder, you can pause for three seconds at the top of the range of motion. For example, pause four seconds at the top of a row to develop a good mind-muscle connection while minimizing momentum.

Rest and Recovery

Allow sufficient rest and recovery between isometric training sessions to promote muscle repair and growth. As I mentioned, isometric exercises can be pretty fatiguing, and many people don’t consider this when adding them to their already fatiguing workouts. It’s important to assess your training volume and adjust over time as needed, especially when adding isometrics to the mix.

Full Body Isometric Workout

As mentioned earlier, you can warm up with isometric training or finish with it to torch your muscles. You can also do a full-on isometric workout. It will feel quite different than your typical workout but don’t let the novelty of static movements fool you. These workouts are killer.

Here is a sample full-body isometric workout that you can try.

Exercise	Sets	Reps/Time	Rest
Pause Squats	3	8-12	3 min
Pause RDL	3	8-12	3 min
Pause Bench Press	3	10-15 sec	2 min
Pull Up Hold	3	20-30 sec	2 min
Wall Sit	3	30-60 sec	2 min
Overhead Carry	3	30-60 sec	2 min

Aim for the higher end of the rep range and select a load that is challenging enough to reach close to muscular failure. Rest sufficiently between sets to allow the nervous system to recover.

Popular Isometric Exercises

Here is an overview of some great isometric exercises from the sample program, along with detailed instructions to get the most bang out of your isometric training.

Wall sit

You probably did these in your middle school gym class. They are hard and don’t require any fancy equipment. One set of these will hit your brain with nostalgia and your quads with nasty burns.

1. Locate a sturdy and clear wall space where you can perform the exercise without any obstructions.
2. Stand with your back against the wall, ensuring your feet are shoulder-width apart. Keep your feet flat on the ground and your toes pointing slightly outward.
3. Slowly slide your back down the wall while bending your knees. Lower your body until your thighs are parallel to the ground as if sitting on an invisible chair. Your knees should be directly above your ankles, and your back should be firmly against the wall.
4. Hold this position as you squeeze your core and quads.

Pause Squats

Squats are great for targeting the quads, glutes, and core muscles. Pause squats involve pausing at the bottom, increasing the tension at the bottom position and forcing you to stay tighter and more stable. They also build tons of strength coming out of the hole aka the bottom of the squat.

1. Position yourself with your feet shoulder-width apart or slightly wider, with your toes pointing slightly outward.
2. Take a deep breath and brace your core.
3. Initiate the squat by pushing your hips back and bending your knees.
4. Once you reach the desired depth of your squat, pause and hold the position for the prescribed duration.
5. Stand back up keeping your spine neutral

Pause Bench Press

The bench press often has sticking points where the barbell seems to stall during the lift. By pausing at these sticking points, you can focus on building strength in those specific ranges, ultimately helping you push through plateaus and improve your full-range bench pressing.

1. Lie on the bench with your eyes directly under the barbell. Grip the barbell with a shoulder-wide overhand grip.
2. Unrack the bar and lower it towards your mid-chest.
3. Pause in this position or press it a couple inches up and hold that position for your desired amount of time. I suggest four seconds.
4. Complete the lift by pressing all the way up.

Pause RDLs

The Romanian deadlift (RDL) is a highly effective exercise for targeting the posterior chain, including the hamstrings, glutes, and lower back. It is an excellent movement for building strength and enhancing the stability of the hip hinge pattern. However, by incorporating a pause into the RDL, you can take the benefits of this exercise to a whole new level by leveraging the benefits of isometric training.

1. Stand with your feet shoulder-width apart or slightly narrower. Position the barbell in front of you, resting on your thighs, with a pronated grip (palms facing you).
2. Initiate the movement by pushing your hips back, allowing the barbell to slide down your thighs. Keep the barbell close to your body as you lower it.
3. Once you reach the desired depth of your RDL, hold the position for 2-3 seconds.
4. Drive through your heels to rise back to the starting position.

Planks

The plank is a simple yet incredibly effective bodyweight exercise that targets the core muscles, including the rectus abdominis, transverse abdominis, and obliques. It is renowned for strengthening the entire core, improving posture, and enhancing overall stability. The OG in isometric training, if you will.

1. Place your forearms flat on the ground, directly below your shoulders. Keep your elbows bent at a 90-degree angle.
2. Lift your body off the floor by pressing through your forearms and toes. Maintain a straight line from your head to your heels.
3. Hold the plank position for as long as you can maintain proper form.

Overhead Carry

With any loaded carry, you’re technically moving, but your hips and upper body are rock solid in this variation to create tightness. These translate well to many sports that require high levels of stability as they train your shoulders, core, and arm muscles in a static position.

1. Choose an appropriate weighted object for the overhead carry, such as a dumbbell or kettlebell.
2. Press the weight overhead, fully extending your arms and keeping your biceps close to your ears. Your palms should face forward.
3. Begin walking forward in a controlled manner while keeping the weight overhead.
4. To finish the overhead carry, carefully lower the weight back to shoulder height before returning it to the starting position.

Unleash Your Static Potential

Isometric training is a valuable addition to any hypertrophy-focused workout regimen. By targeting high motor unit recruitment, prolonged time under tension, and an increased mind-muscle connection, you will unlock new levels of muscle growth. Not to mention, you can do so without the aches and pain associated with traditional dynamic strength training. 

References

1. Nunes J. Does stretch training induce muscle hypertrophy in humans? A review of the literature. Clinical physiology and functional imaging. 2020. Accessed July 28, 2023. https://pubmed.ncbi.nlm.nih.gov/31984621/.
2. Oranchuk D. Isometric training and long-term adaptations: Effects of muscle length, intensity, and intent: A systematic review. Scandinavian journal of medicine & science in sports. 2019. Accessed July 28, 2023. https://pubmed.ncbi.nlm.nih.gov/30580468/.