May 8, 2025, 9:14 am | Read time: 6 minutes

To perform exercises like squats, deadlifts, and push-ups effectively and safely, it’s essential to first strengthen the core muscles. A well-developed core significantly contributes to stability and coordination throughout the entire range of motion. An inadequately developed core increases the risk of injuries, particularly in the back area. FITBOOK fitness expert Alina Bock presents five exercises that strengthen the core muscles and help prevent injuries.

Muscles That Make up the Core

The core, also known as the trunk muscles, consists of numerous muscles. These include:

• rectus abdominis (straight abdominal muscles)
• external oblique (outer oblique abdominal muscles)
• internal oblique (inner oblique abdominal muscles)
• transverse abdominis (transverse abdominal muscles)
• erector spinae (back extensor)
• multifidus
• diaphragm
• psoas major (large lumbar muscle)
• iliacus (iliac muscle)

A Trained and Stable Core Should Be a Prerequisite

The core can be imagined as a kind of corset. The main task of this corset is to provide stability. A strong core helps maintain balance and keeps the body stable during physical activity. As a guarantee of stability, the core supports the spine and ensures an upright posture, protecting against physical ailments such as back pain and injuries. Additionally, the core coordinates movements and acts as a link between the upper and lower body for efficient power transfer, which is essential for successful strength training. Especially for full-body exercises and complex movements like squats, deadlifts, push-ups, and similar exercises, a trained and stable core should be a prerequisite.

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5 Effective Exercises to Strengthen the Core

To ensure stability and safety during strength exercises, especially when working with heavy weights, the core muscles should be strengthened first. The following exercises are ideal for the core.

Mountain Climber on the Bosu Ball

The core is particularly challenged when unstable surfaces are incorporated into the training. Here, the core must compensate for the instability created by the surface, and the involved muscles must work together to create balance.

1. First, get into the starting position: Place the Bosu Ball with the rounded side facing the ground. Grip the edges of the ball or the platform with your hands on either side. The arms are slightly bent. Now, place your toes on the ground and get into the plank position.
2. To activate the core, pull the navel inward and tilt the pelvis toward the ground. The lower back should appear slightly rounded, and the abdominal tension should be noticeable.
3. It’s important for the next step that the body is stable and the balance is well maintained. The body should move as little as possible. Now, alternately pull the knees toward the chest. Here, too, the core should keep the body as still as possible.

To increase intensity, you can pull the knees diagonally toward the chest.

Unlike the conventional Mountain Climber, where speed is emphasized, in this variation, the knees should be pulled toward the body as slowly as possible to allow the body to stabilize.

Bench Press on the Exercise Ball

Another exercise that works with instability is the bench press on the exercise ball. Using dumbbells adds additional instability and particularly challenges the core.

1. Choose a weight for your dumbbells that you can lift, rather than the maximum weight.
2. Lie with your upper back on the exercise ball. Extend your arms and the dumbbells upward. Now, build abdominal tension and maintain it throughout the exercise. The feet should be firmly on the ground.
3. Bend the arms and slowly lower the dumbbells toward the chest. The elbows should point slightly toward the feet. Inhale deeply while lowering the dumbbells.
4. Once at the chest, lift the dumbbells and extend the arms again. Exhale during this process. The core should remain stable throughout the exercise and move as little as possible.

Knee Lift with Leg Extension

A particularly intense exercise that challenges the core is the Knee Lift with Leg Extension.

1. First, get into the quadruped position. The hands are about shoulder-width apart. Now, place your toes on the ground. To create abdominal tension, pull the navel inward and tilt the pelvis toward the ground.
2. Now, lift the knees slightly off the ground. The closer they are to the ground, the more intense the exercise. Ideally, the knees are only one to two centimeters off the ground. Hold the position.
3. After a few seconds, when you can keep your body stable, extend one leg backward. It’s important that the knee of the other leg doesn’t move further from the ground. Hold this position for as long as possible.
4. Pull the leg back in without setting the knees down. Now, switch legs, also without setting the knees down.

The Knee Lift with Leg Extension is a particularly intense exercise where you shouldn’t cheat. If the exercise variation with leg extension is too difficult, you can perform the Knee Lift without it first. If you can and want to increase the intensity, you can also extend the arm diagonally along with the leg.

Toe Touches with Lowered Leg

An exercise that particularly strengthens the abdominal muscles is the Toe Touch.

1. The exercise starts in a supine position. The legs are extended upward. Additionally, the toes are pulled toward the body. The head is lifted off the ground, and the chin is pulled toward the chest.
2. Start with one side: Extend the right arm upward. While exhaling, move the right hand as far as possible toward the left foot. The shoulder blade should lift off the ground.
3. While inhaling, lower the shoulder blade back toward the ground. The head should not be placed down. To support the cervical spine, the left hand can support the head.
4. After several repetitions, lower the right leg toward the ground. The lower the leg, the higher the intensity. After 15 to 20 repetitions, switch sides.
5. On the other side, the right hand supports the cervical spine, the left hand is moved toward the right toes, and the left leg is lowered toward the ground.

Core Stabilization with Partner

Now it gets fun: For the final exercise, a training partner is needed to apply pressure, replacing a cable pull or weight.

1. The trainee stands in front of the training partner. The feet should be about shoulder-width apart, and the knees slightly bent to ensure a stable stance. The arms are extended forward, with the palms facing each other and the thumbs pointing to the ceiling.
2. The abdomen is tensed. Now, the training partner applies pressure to the trainee’s hands, intending to rotate the body. The trainee counters with abdominal tension and tries to keep the body as stable and calm as possible.
3. Regularly switch sides during the exercise.