Rectus Abdominis

The rectus abdominis is the primary muscle of the front of the abdomen and plays a vital role in stabilizing the core and flexing the spine. Running vertically from the rib cage to the pelvis, it works alongside other core muscles to support posture, balance, and efficient movement during both everyday activities and exercise. The exercises below target the rectus abdominis using only dumbbells.

Exercise Menu

Dumbbell Crunches

Primary muscle(s) targeted: Rectus Abdominis & Obliques

Secondary muscle(s) targeted: Transverse Abdominis & Erector Spinae

Compound/Isolation: Isolation

Set-up:

Lie down on a flat surface
Keep your lower body stable
Move the hands behind ears or on opposite shoulders

Execution:

Focus on using your upper abs only
Do not pull with your hip muscles
Picture your ribs sliding down toward hips

The primary muscle worked during dumbbell crunches is the rectus abdominis, the main abdominal muscle responsible for the “six-pack” appearance. The exercise also engages the obliques, which assist with core movement and stabilization during the crunch.

Full Detailed Breakdown

The secondary muscle worked during dumbbell crunches includes the transverse abdominis, which helps stabilize the spine and maintain core tension. The hip flexors and lower back muscles also assist by providing support and stability throughout the movement [3].

Dumbbell crunches are considered an isolation exercise because they primarily target the rectus abdominis and move through spinal flexion, with limited involvement from other muscle groups.

To set up, lie down with your back on a flat surface. Bend the legs and stabilize the lower body. Place your hands either on opposite shoulders or behind the ears, but avoid pulling on the neck or assisting the movement with the arms.

To begin the movement, exhale as you bring your shoulder blades and head off the ground. The lower back should not rise throughout the upwards motion. Breathe in as you lower the body back to the initial position. Maintain a slow, smooth pace as you descend, stopping just before the shoulders touch the ground [1].

Dumbbell Sit-Up

Primary muscle(s) targeted: Rectus Abdominis

Secondary muscle(s) targeted: Obliques, Hip Flexors, & Quadriceps

Compound/Isolation: Compound

Set-up:

Grab dumbbell and lie down
Knees bent at 90°
Grip the weight in front of the chest

Execution:

Engage your hip flexors to help pull you upward
Work the full abdominal wall all together
Feet anchored down completely

The main muscle working during a dumbbell sit-up is the rectus abdominis, which runs along the front of the abdomen and is responsible for flexing the trunk as you raise your upper body toward your knees.

Full Detailed Breakdown

In addition to the rectus abdominis, the dumbbell sit-up also engages the obliques, hip flexors, and quadriceps, which help stabilize the body and assist with the movement throughout the exercise [2].

The dumbbell sit-up is considered a compound exercise because it involves movement at multiple joints and works several muscle groups, including the abdominal muscles, hip flexors, and leg muscles, at the same time [3].

To set up, grab a dumbbell of appropriate weight and sit on the floor. Hold the weight in front of your chest and lie down on the ground. Bend your knees at a right angle, and keep your feet firmly planted on the ground for stability.

To begin the movement, exhale as you engage the core and lift your upper body off the floor. Raise your torso toward your knees until your forearms or the dumbbell touch your thighs, keeping your hips and feet grounded. Hold the top position for a few seconds, contracting the abdominal muscles, then start descending. Lower your torso back down to the floor slowly in a controlled manner to finish the movement [2].

Dumbbell V-Up

Primary muscle(s) targeted: Rectus Abdominis & Oblique Muscles

Secondary muscle(s) targeted: Hip Flexors, Adductors, & Quadriceps

Compound/Isolation: Compound

Set-up:

Hold the dumbbell firmly over your head
Press your lower back down into the floor
Point your toes straight out to engage your legs

Execution:

Lift torso and legs simultaneously
Do not let your lower back arch up
Speed should be steady and controlled

The primary muscles worked during the dumbbell V-up are the rectus abdominis and the oblique muscles. The rectus abdominis is responsible for lifting the torso and legs to create the V shape during the exercise.

Full Detailed Breakdown

In addition to the abdominal muscles, the V-up also engages the hip flexors, adductors, and quadriceps. These muscles help lift and stabilize the legs while maintaining balance and proper body positioning throughout the movement.

The V-up is considered a compound exercise, as it works multiple muscle groups at the same time, including the abdominal muscles, hip flexors, and several lower-body muscles during a single repetition.

To set up for a V-up, lie flat on the ground with your arms extended overhead holding a dumbbell of manageable weight. Straighten your legs and keep your feet together, then point your toes straight forward to target the lower muscle groups.

Exhale as you engage your core to lift your torso and legs at the same time to create a ‘V’ shape with your body. Keep both your arms and legs straight and keep the weight or dumbbell overhead.Inhale as you engage your core and slowly lower your body down to the floor. Make sure your arms are extended above your head and your legs are straight throughout. Keep your feet about 6 inches off the floor to keep them engaged [4].

References

[1] Cherney, K. (2023, April 7). Situps vs. crunches. Healthline. https://www.healthline.com/health/fitness-exercise/sit-ups-vs-crunches

[2] Higuera, V. (2019, June 24). How to Do weighted situps and variations. Healthline. https://www.healthline.com/health/weighted-situps

[3] Oliva-Lozano, J. M., & Muyor, J. M. (2020). Core muscle activity during physical fitness exercises: A systematic review. International Journal of Environmental Research and Public Health, 17(12). https://doi.org/10.3390/ijerph17124306

[4] Twu, A. (2024, December 8). How to do v-ups. WebMD. https://www.webmd.com/fitness-exercise/how-to-do-v-ups