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9 Sit Up Alternatives For Back Pain

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Traditional sit-ups have been a popular abdominal exercise for centuries, but they’re also infamous for producing lower back pain and discomfort.

Fortunately, there are better ways to target your abs that won’t aggravate your back.

As a personal trainer, I work with a lot of people with back issues. Quite a few of them come to me after having done sit ups since their school days.

Over the years, I’ve developed an arsenal of ab-specific exercises that they can do without any worries about aggravating their back. 

In this article, I’ll lay out the 9 most effective back-friendly sit up alternatives that I currently use with my personal training clients.

What is wrong with sit ups? 

You were probably taught to do the traditional sit up when you were a young kid in primary school.

It likely involved having another kid push down on your feet as you, with your hands clasped behind your head, pulled your torso all the way up so that your elbows touched your knees.

Sit up - muscles worked

This version of the sit up has since been recognized as a terrible exercise. Here are three reasons why you shouldn’t be doing it:

1. Sit ups put too much pressure on the spine

Swedish researcher Dr. Alf Nachemson of Sweden completed one of the most well-known studies on the effects of sit-ups on the spine.

Nachemson measured the pressure on the lumbar spine during various workouts for the study.

Of all the activities examined, the sit-up produced the most pressure on the spine.

It was shown that the pressure on the lumbar spine discs during sit-ups ranged from 2500 to 3300 N (Newtons), as opposed to just 400 to 700 N when standing, walking, and other commonplace activities.

In order to put this into perspective, the recommended safe limit for disc pressure is somewhere around 3100 N.

This means that performing sit-ups can cause the spine to be compressed up to or past this safe limit. 

For people who already have lower back problems or who perform sit-ups improperly, this can be very dangerous.

The increased pressure inside the spinal discs makes you more susceptible for a herniated disc.

The chart above compares the study report and illustrates how doing sit-ups puts far more pressure on the spine than doing other exercises.

This emphasizes the possibility that sit-ups could harm the spine and supports the idea that different exercises might be a better option for people trying to develop their core without endangering their spinal health.

2. Sit ups work the hip flexors more than the abs

The abdominal muscles are frequently thought of as the primary target of the sit-up exercise. In reality, it’s the hip flexor muscles, not the rectus abdominis, that are what move the body during a sit-up.

The psoas major and rectus femoris, which are hip flexors, contract during a sit-up to bring the thighs closer to the chest. This movement elevates the torso off the ground thanks to posterior pelvic tilt.

The hip flexors play the primary function in the movement (80%), followed by the abdominal muscles (20%).

Doing an exercise that only works the target muscle 20% does not represent smart training. Beyond that, though, the reliance on the hip flexors can cause problems in itself.

In many people, the hip flexors are tight and overworked because they are sitting down for a large part of the day.

The extra work done through sit ups can make them tighter still, contributing to bad posture and increasing lower back pain. 

Depending on the hip flexors during sit-ups might also result in the lower back arching, which can aggravate lower back problems and put more strain on the muscles in that region.

3. Sits ups are bad for posture

Performing sit-ups frequently involves flexing the spine, which can shorten and tighten the hip flexors. When the hip flexors are tight, they can tilt the pelvis anteriorly, which can result in an overly arched lower back.

This can contribute to hyperlordosis, a postural imbalance marked by an excessive curving of the lumbar spine.

The kyphotic curve is the natural gentle outward curve of the upper spine. When performing sit-ups, many people have a tendency to round their shoulders and lean over, which can lead to an overly flexed thoracic spine (upper back).

This may contribute to kyphosis, a postural disorder characterized by an excessive kyphotic curve.

Abdominal anatomy

The rectus abdominis is a long and flat band of muscle that travels vertically along the front of the abdomen. Fibrous bands, known as tendinous junctions,  separate the muscle into segments, giving it the distinctive six-pack appearance.

The rectus abdominis’ main job is to bend the trunk, which aids in bringing the ribs closer to the pelvis. It also helps to keep the pelvis and spine stable while moving, especially when engaging in forward bending or twisting motions.

Exercises for the abs that target the rectus abdominis should incorporate trunk flexion in order to work this muscle effectively. 

How many reps for the abs?

You’ll often see people doing very high reps when doing sit ups or any other ab exercise. Often this is done, even subconsciously, because people think they can spot reduce body fat from their belly area.

However, this is a misconception. The only way to reduce belly fat is to burn it off through cardio exercise and to reduce your caloric intake to create a negative calorie balance.

The abs should be worked with a similar rep range to any other muscle group. You should work a range of reps from a high of around 30 down to a low of 8-10.

The best exercise for the abs will allow you to add resistance as you reduce the rep count. 

The key to effectively working the abdominals is to focus, not only doing hundreds of reps, but on using good form and progressively overloading the muscle. 

We should also keep in mind that the abs are a pretty small muscle group compared to larger muscles like the pectorals or quads.

As a result, they may not need as much frequency or volume. 

There is evidence to suggest that doing too many reps for the abs may actually be counterproductive. A study by Escamilla, et al. suggested that doing more than 30 reps of an ab exercise may lead to reduced abdominal muscle activation. 

I recommend that my personal training clients work their abs twice per week, doing 4 sets with the following rep range:

  • Set One: 30 reps
  • Set Two: 20 reps
  • Set Three: 15 reps
  • Set Four: 10 reps

Equipment needed for these exercises

9 sit up alternatives that replicate the same movement pattern

Sit up alternatives infographic

1. Cable crunches

Equipment needed for cable crunches:

REP FT-5000

REP Fitness FT-5000 Cable Machine
Read our best cable machine guide here

This is the cable machine we recommend for ‘most people’.

We compared over 100 cable machines against 10 criteria. This is our highest-ranked cable machine.

The main reason is this is commercial-like quality for a reasonable price.

It also boasts a 224lbs weight stack on both sides. Comparable models have sub 200lbs.

Some cable machines can feel a bit wobbly during certain exercises, but the FT-5000 provides exceptionally stable and smooth resistance throughout the entire range of motion.

How to do cable crunches:

  1. Set the pulley on a cable machine to its shoulder level level when you are standing and put a rope handle on the end of the pulley. 
  2. Position a bench three feet in front of the cable machines and sit on it, facing away. 
  3. Sit on the bench and grab the rope handle above your head. 
  4. Crunch down to bring your chest toward your knees. Keep your lower back against the bench pad, rounding with the upper back. Forcefully contract your abs. Reverse the action to return to the start position. 

Exercise muscles worked:

  • Abdominals
  • Obliques

2. Kneeling cable crunches

Equipment needed for kneeling cable crunches:

REP AB-3000 Bench

REP AB-3000 Weight Bench
Read our best weight bench guide here

This is the weight bench we recommend for ‘most people’.

We compared over 70 benches against 12 criteria. This is our highest-ranked flat, incline & decline (FID) bench.

Some adjustable benches can be a bit wobbly when on the incline. But the AB-3000 is very sturdy.

With a height 18mm it’s comparable to benches that cost twice as much.

How to do kneeling cable crunches:

  1. Set the pulley on a cable machine at its highest setting. Put a rope handle on the cable.
  2. Stand about three feet in front of the machine, facing away from it. Grab the handles and kneel on the floor. Position your hands at forehead level. Your back should be in a neutral position and your butt should be sitting on your heels.
  3. Crunch down as you round your back to fully contract the rectus abdominis muscle.
  4. Slowly return to the start position. 
  5. Do four sets, increasing the weight on each succeeding set. 
  6. On set one, do 30 reps, then 20, 15, and 10 reps.

Kneeling cable crunches muscles worked:

  • Abdominals
  • Obliques

3. Weighted crunches

Equipment needed for weighted crunches:

How to do weighted crunches:

  1. Get down on the floor, with a weight plate in your hand. Lie on your back with your knees bent. Place the weight plate over your chest area.
  2. From a starting position with your head on the floor and your spine in a neutral position, round the back as you crunch up to fully contract your rectus abdominis. 
  3. Hold the top position for a two second count.
  4. Lower and repeat.

Weighted crunches muscles worked:

  • Abdominals
  • Lower back

4. Starfish crunch

Equipment needed for the starfish crunch:

  • None

How to do the starfish crunch:

  1. Lie spread eagled on the floor with your arms and legs stretched out starfish style. 
  2. Without bending your knees, attempt to bring your right hand and left foot into contact with each other. You should only be lifting your shoulder blades from the floor. Feel a deep contraction in the abs in the top position. 
  3. Return to the start position, controlling the movement,  and repeat with the other side.

Starfish crunch muscles worked:

  • Abdominals
  • Lower back

Rotator cuff problems preventing you from overhead lifting? Check out our 9 overhead press alternatives for the ultimate body.

5. Twisting pistons

Equipment needed for twisting pistons:

  • None

How to do twisting pistons:

  1. Get down into a plank position, resting on your elbows and your toes, with feet together. 
  2. Keeping your butt down, bring both feet up to the left toward your left elbow. 
  3. Immediately kick them back and then up toward the right knee. 
  4. Continue this fluid piston-like motion until your prescribed number of reps has been achieved.

Twisting pistons muscles worked:

  • Abdominals
  • Lower back

6. Bicycle crunches

Equipment needed for bicycle crunches:

  • None

How to do bicycle crunches:

  1. Lie on an exercise mat with your legs out straight and your hands alongside your ears (do not clasp your hands together). 
  2. Lift your feet off the ground and lift your head and shoulders.
  3. Begin a cycling action with your legs, simultaneously bringing your elbows across to the opposite knee.

Bicycle crunches muscles worked:

  • Abdominals
  • Lower back

7.  V-ups

Equipment needed for V-Ups:

  • None

How to do V-Ups:

  1. Lie on an exercise mat on your back with legs extended and arms by your side. 
  2. Hinge at your hips to bring your straightened legs up until they are perpendicular with your torso. 
  3. Straighten your arms up toward your legs. 
  4. Begin pulsing up toward your toes by contracting your abdominals. Bring your head up on each pulse.

V-Ups muscles worked:

  • Abdominals
  • Lower back

8. Crunches (legs high)

Equipment needed for legs high crunches:

  • None

How to do legs high crunches:

  1. Get down on the floor, with your hands by your ears. Lie on your back with your knees bent. Now lift your lower legs so they are parallel with the floor, crossing your ankles over.
  2. From a starting position with your head on the floor and your spine in a neutral position, round the back as you crunch up to fully contract your rectus abdominis. 
  3. Hold the top position for a two second count.
  4. Lower and repeat.

Legs high crunches muscles worked:

  • Abdominals
  • Lower back

9. Touch toe abs

Equipment needed for touch toe abs:

  • None

How to do touch toe abs:

  1. Lie on an exercise mat with your legs out straight and your arms extended beyond your head. 
  2. Pivot at the hips and tense your core to bring your torso up and your hands to your toes. 
  3. Lower and repeat. Maintain a neutral spine throughout this action. 

Touch toe abs muscles worked:

  • Abdominals
  • Lower back

Note: if you want even more ideas on how to develop your core muscles, be sure to check out our hanging leg raise alternatives and get inspired with more core-targeting exercise ideas.

Sit up alternatives: The bottom line

If the one message you got from this article is to never do another sit up in your life, then my efforts have been well worth it! 

You’ve been provided with 9 super effective sit up alternatives that target the rectus abdominis without putting strain on your lower back.

I recommend experimenting with all 9 of these exercises to discover which ones work best for you.

Then choose the best two or three and alternate them as you work your abs a couple of times per week.

Are you looking for a complete beginner resistance routine that will work your muscles safely and effectively? Check out our 12 week beginner’s weight lifting routine.

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Steve is a certified personal trainer, current home gym owner, former gym owner, and copywriter. He joined his first gym at age 15 and, five years later, he was managing his own studio. In 1987, he became the first personal fitness trainer in New Zealand.

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