Isometric exercises: learn the fastest and safest way to gain strength

In the world of fitness training, the focus is often on movement—lifting, running, jumping, pushing— with dizzying routines and explosive repetitions. However, there is one form of exercise that defies that logic and offers dramatic results: isometric exercises.

These are non-displacement muscle contractions in which the body remains in a fixed position for a few seconds, generating tension without moving. Although they may seem simple, their impact on strength development is profound and backed by scientific evidence.

“Isometric exercises generate a muscle contraction without any movement in the joint,” explains Sol Candotti, a physical trainer consulted by La Nación (Argentina). “You're exerting force, the muscle is active—especially when the contraction is held for around 30 seconds—but there's no movement. This is key because it allows for safe, controlled, and highly targeted training.”

During these exercises, there is no impact, and while the muscles are under tension, their length doesn't change, and the joints and tendons are relaxed, thus avoiding the risk of potential injuries caused by improper movement, adds Maia Rastalsky, a physical trainer.

In situations where movement is limited by pain or when you're looking to target specific areas without putting too much strain on your joints, these exercises become especially relevant. "They're ideal for stabilizing joints. For example, if you want to build strength in your knees without overloading them, it's very effective," says Candotti. "They also generate very little fatigue, which allows you to train more times per week without compromising recovery."

Because of these two benefits, the American College of Sports Medicine (ACSM) notes that this type of training is key for special populations, such as older adults, people undergoing rehabilitation, or even beginners developing body awareness. For Jano Steinhardt, a classical Pilates instructor, this type of exercise is the fastest way to develop strength and muscle tone, especially in situations where there is a strength deficit (such as during rehabilitation).

Furthermore , by maintaining muscle tension for a short period of time, but through various stimuli, these positions correct and help maintain good posture and body strength, says Rastalsky.

A Mayo Clinic report notes that "they can be useful for enhancing joint and torso stability," while Medical News Today explains that when a muscle contracts, its tissues fill with blood, generating metabolic stress that allows it to improve strength and endurance. Candotti, for his part, points out that this training method also has cardiovascular benefits. "Recent clinical studies show that exercises such as hand-held grip exercises help reduce blood pressure and may be more effective than traditional aerobic exercises such as walking or cycling," he explains.

Although these exercises are designed to be performed with your own body weight, without any extra equipment, Rastalsky points out that weights or other weight-bearing equipment can sometimes be added to increase the intensity.

Regarding time and repetitions, Diego Demarco, a physical trainer specializing in exercise physiology and high performance, comments that this is a matter that must be evaluated individually: "It's likely that someone who's just starting out in training won't be able to hold a position for the same amount of time as someone who's trained. It's a progressive process." In this sense, Rastalsky emphasizes the importance of guidance and supervision, at least at the beginning, to ensure that exercises are performed correctly.

Most conventional movements, those that involve muscle extension, can be adapted to isometric exercises, so it's possible to train all areas of the body with this technique: from the upper body to the midsection to the lower body. Rastalsky identifies the following as the most popular exercises:

This exercise allows you to work the abdominal area, back, shoulders and glutes.

- Lie face down on the floor or a mat.

- Carry your body weight on your elbows and stand on your toes.

- Raise your hips and keep your posture in a straight line.

- Beginners can switch from supporting themselves on their elbows to using their hands.

- Another variation is to do the plank laterally to specifically work the oblique abdominals and the hips.

The tension is mainly located in the abdominal area, although the resistance of the lower and upper body is also worked.

- Lie on your back on a flat surface.

- Lift your head, neck and shoulders.

- Stretch your arms back with your head in the middle.

- Extend your legs at 45 degrees from the ground.

It allows you to exercise your legs: quadriceps and glutes, and your core, which will allow your body to be balanced and in equilibrium to maintain your posture.

- Stand straight with your gaze straight ahead, your back fully against a wall, and your legs hip-width apart, forming a 'V'.

- Slowly slide down until your knees are bent.

- The arms should be stretched forward or resting on the quadriceps.

- Another option is to do the squat in the air, without leaning against a wall.

This pose works the upper body: shoulders, arms and back, but also the core, which is where the force is generated.

- Stand straight with your gaze facing forward and your legs hip-width apart.

- Using a weight or dumbbell, raise your arms out to the sides to shoulder height.

This position works the muscles of the glutes and hips, as well as the abdominals, which must be firm to maintain the body's balance.

- Lie on the floor on a mat, face up, or rest your back on a bench or box.

- Support your back and bend your legs, ensuring that your feet are hip-width apart and flat on the floor.

- Place your arms stretched out at your sides with your palms facing down. Raise your hips slightly and hold the position.

"Isometric exercises are suitable for any age, for rehabilitation or as a complement to functional or performance training," says Sol Candotti, physical trainer.

The Mayo Clinic notes that people with arthritis could benefit especially from this training, arguing that the condition could worsen if joint movements are performed. "Improved strength can reduce pain and improve physical function," they explain in a statement.

However, there is a contraindication. Diego Demarco, a physical trainer specializing in exercise physiology and high performance, advises against isometric exercises for people with high blood pressure or cardiovascular problems . "Even if you're not generating movement, when the muscle is tense, it compresses blood flow, so the heart will use more force to pump blood. This doesn't happen during dynamic exercises, where you manage blood pressure through breathing," warns the expert.

The ACSM Guidelines endorse isometric exercises as an effective tool for strength development, but clarify that they shouldn't be the sole strategy. Along these lines, Candotti recommends complementing them with other types of training. "Ideally, you should combine them with dynamic exercises to work the full range of motion," he concludes.