Seated Alternate Crunch
- Músculo objetivo
- Iliopsoas, Rectus Abdominis
- Músculos sinergistas
- Quadriceps, Sartorius, Tensor Fasciae Latae
- Equipamiento
- Body weight
- Parte del cuerpo
- Hips, Waist
- Tipo
- Strength
The seated alternate crunch is a bodyweight core exercise that targets the iliopsoas and rectus abdominis while recruiting the quadriceps, sartorius, and tensor fasciae latae as synergists. Performed from a seated position, it alternates knee drives toward the opposite elbow to challenge hip flexion and trunk flexion in the same movement. It is well suited for building core strength and hip flexor endurance without any equipment.
Cómo hacer el Seated Alternate Crunch
- 1Sit on the floor with your knees bent and feet flat. Lean back slightly until your torso is at roughly a 45-degree angle and your core is engaged.
- 2Place your hands lightly behind your head with your elbows wide, or cross your arms over your chest — whichever feels more comfortable.
- 3Brace your abdominals and press your lower back toward a neutral position to avoid excessive lumbar rounding.
- 4Lift your right knee toward your chest while simultaneously rotating your left elbow to meet it, crunching through the waist.
- 5Pause briefly at the top, feeling the contraction in your rectus abdominis and hip flexors.
- 6Return your right foot toward the floor and your torso toward the starting angle in a controlled manner — do not fully lower between reps.
- 7Immediately drive your left knee up and rotate your right elbow to meet it, completing one full repetition.
- 8Continue alternating sides for the desired number of reps, keeping your feet from touching the floor if you want to increase the difficulty.
Consejos de técnica
- Keep your chin off your chest — imagine holding a tennis ball under your chin to maintain neutral head position and reduce neck strain.
- Focus on rotating at the waist rather than pulling your elbow toward your knee with your arms; the power should come from your core.
- Control the descent on each rep rather than letting gravity drop your torso — the slow return adds time under tension to the rectus abdominis.
- Breathe out as you crunch and drive the knee up, and inhale as you lower back toward the starting position.
- If your hip flexors fatigue before your abs, shorten your range of motion slightly and prioritize the trunk rotation component.
Errores comunes
- Pulling on the neck with your hands, which shifts stress away from the core and can cause cervical strain — keep your hands light and your elbows wide.
- Letting your feet rest on the floor between reps, which removes tension from the iliopsoas and rectus abdominis and reduces the effectiveness of the set.
- Using momentum to swing the torso rather than controlling each rotation, which bypasses the core muscles and increases injury risk.
- Rounding the lower back into a deep C-curve instead of maintaining a moderate lean, which places excessive stress on the lumbar spine.
- Rushing through reps to hit a number rather than feeling each contraction, which sacrifices muscle activation for pace.
Preguntas frecuentes
What muscles does the seated alternate crunch work?
The primary muscles are the iliopsoas and rectus abdominis. The quadriceps, sartorius, and tensor fasciae latae act as synergists to support the knee-drive portion of the movement.
Is the seated alternate crunch good for beginners?
Yes. It requires no equipment and the range of motion is easy to scale. Beginners can tap their feet lightly on the floor between reps and use a smaller rotation until they build enough core strength and hip flexor endurance to maintain a hover throughout the set.
How many sets and reps should I do?
Two to three sets of 12–20 alternating reps (6–10 per side) works well for most people. Because this is a bodyweight exercise, higher rep ranges with controlled tempo tend to produce better results than racing through a low rep count.
What is the difference between a seated alternate crunch and a bicycle crunch?
The movements are similar, but a bicycle crunch is typically performed lying on your back with your legs fully extended and cycling through the air. The seated alternate crunch keeps you upright at a fixed lean angle, which shifts more load onto the hip flexors and changes the stability demand on the core.
Why do my hip flexors fatigue before my abs during this exercise?
The iliopsoas works hard to hold your legs up and drive each knee toward your torso. If your hip flexors fatigue first, try briefly tapping your feet down between reps to give them a short rest, or reduce your torso lean slightly to shift more of the load onto the rectus abdominis.
