There is an oddly serious debate about the humble abdominal curl. One corner of the gym treats it as the missing key to every sporting goal; another talks as though rounding the spine once will set off an alarm. The movement deserves a calmer look. In the video on this page, osteopath Heath Williams demonstrates a cable abdominal curl that combines a deliberate curl through the spine with some movement at the hips. The cable supplies resistance as the trunk folds, and the return is controlled. It is a useful demonstration of one way to train the abdominal muscles, rather than a universal prescription.
If you are watching between meetings in Melbourne CBD and wondering whether this belongs in your program, the answer depends on what you want from it and how it feels. A cable curl can be an efficient way to practise and load trunk flexion. It will not, on its own, prevent back pain, make running injury proof or reveal a six pack by Friday.
What the cable changes
The rectus abdominis, the long muscle down the front of the abdomen, helps bring the rib cage and pelvis towards one another. The external and internal obliques assist with trunk movement and control. On the way down in a curl, the abdominal muscles shorten while producing force. On the return, they remain active as they lengthen and control the cable’s pull. That second half of the rep is training too. Letting the weight stack yank you upright turns it into a much shorter exercise.
A floor curl uses body weight, which may be plenty. The cable makes resistance easier to adjust in small steps. That matters when the aim is to build strength rather than collect ever larger rep counts. The 2026 American College of Sports Medicine position stand reviewed 137 systematic reviews of resistance training in healthy adults. Its broad message is that progressive training works and that consistency and suitable effort matter more than fancy equipment or routinely reaching absolute failure. The position stand did not test this cable curl against every other abdominal exercise, so it cannot crown a winner.
The cable also gives immediate feedback. If the load is so heavy that your arms pull the handle down while your trunk barely moves, the weight has answered the question for you. If you can move smoothly, pause briefly and return under control, you are more likely to be loading the motion you intended. There is no need to select a number from a generic strength chart before you can make that judgement.
Two movements can share one repetition
The original demonstration includes spinal flexion and hip flexion. They are related but not identical. Spinal flexion is the curl that brings the ribs towards the pelvis. Hip flexion is the movement of the trunk towards the thighs. When a person simply folds at the hips with a stiff torso, the exercise begins to look like a weighted bow. When the arms do most of the pulling, it looks like a rather awkward lat pulldown. Neither is a moral failure, but both change where the effort goes.
Muscle activation studies help explain why technique matters, although they are often oversold. In a study comparing trunk training movements, exercises combining spine and hip flexion recruited the abdominal muscles and hip flexors differently from a simpler curl. A later curl up experiment also found that hip position and breathing altered measured abdominal activity. These are short laboratory measurements; a stronger electrical signal during one rep does not prove better long term muscle growth or a clinical benefit. They do tell us that “an ab exercise” is not one fixed mechanical event.
This is why the video is worth watching closely. Follow the movement of the rib cage as well as the path of the hands. The useful sensation is controlled effort through the front of the trunk, without having to hold your breath or wrench through a painful range.
A rep worth doing slowly enough to notice
Set the cable at a height and resistance that let you take the position shown in the video without being pulled off balance. Keep a comfortable base. Start tall enough to allow a small curl rather than already being folded in half. As you exhale, think about bringing the lower ribs towards the pelvis. Let the hips bend only as much as is comfortable for this version. Then allow the trunk to uncurl under control instead of springing back. The spine does not need to become a perfect circle, and the handle does not need to touch the floor.
The first few repetitions are a rehearsal. Can you feel the trunk moving, or have the shoulders and arms taken over? Can you keep breathing? Does the load let you control the return? A modest weight and a shorter comfortable range are sensible starting choices. Add resistance only after you can repeat the motion without relying on momentum. If you feel sharp back pain, radiating leg symptoms, abdominal pain or a new pressure or bulge, stop and have the symptom assessed rather than pushing through for a round number of reps.
People often ask for the ideal tempo or rep count. There is no cable curl specific trial that supplies a universally effective formula. For general resistance training, the 2026 position stand found that exact equipment type, time under tension and training to failure did not consistently change outcomes for the average healthy adult. Choose a load that demands attention while leaving you in control. Two or three considered sets within a broader program may be more useful than one frantic set at the end of a workout, but total training and individual tolerance should determine the dose.
A crunch and a plank ask different questions
A plank asks the trunk to resist movement while the arms and legs support the body. A cable curl asks it to produce and control movement against resistance. Both are legitimate; neither is a compulsory test of whether you have a “real core.” If your goal is to get stronger in trunk flexion, practising trunk flexion makes sense. If your sport or work asks you to hold position while force travels through your body, exercises that challenge that control also make sense. Many people will benefit from a mix of movements rather than an exclusive relationship with one exercise.
Nor does a burn in the abdominals tell you that belly fat is leaving the area. A small randomised trial of abdominal exercises found no reduction in abdominal fat measurements from the exercise program alone. A 2023 trial using high volume abdominal endurance training reported a regional fat effect under a very different protocol, so blanket statements about “spot reduction” need some care. Neither study shows that a few cable curls will change waist size. Train this movement for a movement or strength reason; let broader activity and nutrition serve any body composition goal.
What about the spine
The spine is built to move, including into flexion. That does not make every loaded flexion exercise right for every person on every day. Tissue tolerance, symptoms, dose and medical history matter. The usual internet choice between “all spinal bending is dangerous” and “anyone can crunch through anything” is a poor substitute for assessing the person in front of you.
For chronic low back pain, the World Health Organization guideline supports exercise programs as part of a broader, person centred approach. It does not single out cable curls as a treatment. In a 2024 randomised trial of 56 people with chronic axial back pain, an extension focused exercise program reduced average pain more than a flexion focused program at one year, while functional scores were similar. The programs were not cable curls, the sample was small, and the result does not prove flexion harms healthy backs. It does warn against prescribing repeated flexion as an automatic remedy for someone whose back dislikes it, particularly if leg symptoms are involved.
An exercise that feels fine to one gym goer may be provocative for another person with a recent flare. There is no prize for “correct form” if the chosen movement keeps making symptoms worse. Adjusting range or load, choosing a different exercise, or seeking assessment are ordinary training decisions, not evidence that a spine is fragile.
When this exercise belongs in rehabilitation
Rehabilitation is more specific than adding an ab finisher to every workout. For one person, the first step after a back flare may be walking and comfortable general movement. Another may be ready for strength training but prefer a plank or a standing cable exercise before loaded spinal flexion. Someone preparing for lifting or sport may eventually want the option to bend and resist load in more than one direction. There is no reason to claim that one curl corrects a hidden imbalance or guarantees freedom from back pain.
At Principle Four Osteopathy in Melbourne CBD, exercise rehabilitation can be matched to a person’s symptoms, capacity and goal. That may mean changing the curl’s range or load, selecting a different exercise, or building a broader strength and conditioning program. Hands on care can support comfort and movement where appropriate, but the useful long term question is what you can practise and progress between appointments. For persistent or worsening back symptoms, a proper assessment matters more than collecting exercise videos.
The useful takeaway from the video
Watch the curl as a lesson in controlled loading: fold through the trunk, let the hips move as intended, and make the return an active part of the rep. If it suits your goals and your body, progress it gradually. If it does not, there are other ways to train the abdominal wall. The cable station is a tool, not an exam you must pass before you can call yourself strong.