If you're considering an AbCoaster, you've probably heard it works your "entire core." While that’s true, it doesn't tell you much. The AbCoaster muscles worked deserve a proper breakdown, because understanding which fibers fire (and how hard) is the difference between training your abs strategically and just going through the motions. This guide walks through every muscle that The Abs Company’s AbCoaster activates, with research backing the claims that have it, and acknowledgment where the research is thinner.
Five muscle groups get worked on every rep. Here’s what each one does and how the AbCoaster activates it.
The rectus abdominis is the flat sheet of muscle running from your sternum down to your pubic bone—the muscle that shows up as the "six-pack" when developed and lean enough. It’s anatomically one muscle, but it has upper and lower regions that respond slightly differently to different exercises. The AbCoaster’s bottom-up knee pull loads the rectus abdominis through full spinal flexion.
Research comparing the AbCoaster to traditional crunches showed comparable activation of both the upper and lower rectus abdominis, meaning the AbCoaster trains the visible six-pack muscles just as effectively as a crunch does [1]. The advantage of this innovative ab machine over a crunch isn’t raw activation here; it’s the range of motion, joint safety, and ability to add progressive resistance, which we’ll get to.
The external obliques are the lateral abdominal muscles you can see running diagonally down the sides of your torso. They’re responsible for trunk rotation, lateral flexion, and stabilizing the spine during rotational movement. They’re also a meaningful contributor to that "tapered waist" look when trained consistently.
This is where the AbCoaster genuinely outperforms the crunch. The same EMG research we mentioned earlier shows that the AbCoaster produces significantly greater external oblique activation than the traditional crunch. The reason is the freestyle motion seat: when you pull the carriage at an angle instead of straight up, the obliques have to work hard to control the rotational and lateral movement. Crunches don’t replicate this.Â
The internal obliques sit beneath the external obliques and run in the opposite diagonal direction. They handle the same functions: rotation, lateral flexion, and spinal stability from the deeper layer of the abdominal wall, and they’re critical for everyday movement like twisting to grab something or bracing during a heavy lift.
The AbCoaster activates the internal obliques alongside the external obliques during angled and rotational reps along the curved track. While there’s less AbCoaster-specific EMG data on internal obliques than externals (limited research), the movement pattern necessarily engages both layers. You cannot rotate the trunk against resistance without recruiting both, which is exactly why the AbCoaster trains the whole core rather than isolated regions.
The transverse abdominis is the deepest abdominal layer. It wraps around the trunk like a corset and stabilizes the spine and pelvis throughout almost every movement you make. It’s also one of the hardest muscles to train deliberately, because most ab exercises focus on the surface muscles. On the AbCoaster, the transverse abdominis fires isometrically throughout every rep, holding the pelvis and lumbar spine stable while the padded carriage moves through the curved track.Â
The hip flexors, primarily the iliopsoas and rectus femoris, assist in lifting the knees toward the chest during the AbCoaster pull. This is a secondary activation, not a primary one. The AbCoaster is an ab machine, not a hip flexor trainer, and its curved track is specifically engineered to minimize hip flexor dominance, so the abs do most of the work.
If you feel your hip flexors taking over during the movement, the typical fix is checking proper form: from the starting position, keep your spine slightly rounded through the pull rather than initiating with the legs, and the load shifts back into the abs.
If you want to see the differences between muscles trained by crunches vs using an AbCoaster, here’s a quick recap with additional comparisons based on research. Spoiler: the AbCoaster has real advantages over crunch and other common abdominal exercises (like the ab wheel and ab roller).
Rectus abdominis (upper and lower): No significant difference between AbCoaster and traditional crunch; both effectively activate the visible six-pack muscles.
External obliques: AbCoaster significantly higher activation than the traditional crunch; this is the clearest AbCoaster win.
Spinal compression: Traditional crunches place relatively high pressure on the lumbar intervertebral discs through repeated flexion [2]; the AbCoaster’s kneeling position and guided curved track keep the spine in neutral alignment throughout the movement.
Range of motion: The AbCoaster allows a greater functional range of motion than a floor crunch can deliver—more time under tension, more complete engagement per rep.Â
Crunches and the AbCoaster activate the rectus abdominis at comparable levels, but where the AbCoaster pulls ahead of the standard crunch machine, the ab roller, and most floor work is on oblique activation, spinal safety, and the ability to add progressive resistance over time. If you’ve been training with crunches for years and your obliques still look flat, that’s the gap the AbCoaster closes.Â
Considering getting an AbCoaster machine, but can’t decide which one to get? We wrote an AbCoaster Comparison Guide to help with exactly that.
The AbCoaster trains the rectus abdominis muscles that form the six-pack, but visible abs are a function of body fat percentage as much as muscle development. You can train the rectus abdominis hard for months and still not see definition if your body fat is too high. The AbCoaster builds the muscle; a balanced diet and overall regular exercise reveal it.
Most users feel meaningful core strength improvements within 3-4 weeks of consistent use (3-4 sessions per week). Visible muscle development typically shows up in the 8-12 week range, assuming nutrition and overall training and progression are dialed in. As with any home gym training tool, consistency matters more than intensity.
For most users, no. The AbCoaster covers the rectus abdominis, obliques, and deep core stabilizers from a single station. The one area worth supplementing is anti-rotation work (Pallof presses, side planks) if you train for sports or work with physical therapists on rotational stability.
The AbCoaster strengthens and develops the obliques, which can contribute to a more defined waistline over time. But you can’t spot-reduce fat from any area of the body — overall waist size is primarily determined by body fat percentage, weight loss progress, and genetics. The AbCoaster will tighten and define the muscles around the waist; whether that translates to a visibly smaller waist depends on what’s sitting on top of those muscles.
Five muscle groups, one ab coaster machine: the AbCoaster trains the upper and lower rectus abdominis, the external obliques, the internal obliques, the transverse abdominis, and recruits the hip flexors as a secondary mover. The standout finding from the EMG research is the oblique activation. It’s significantly higher than what a traditional crunch produces, which is exactly the muscle group that most floor-based ab work consistently underworks. Combine that with comparable rectus abdominis activation, no spinal compression on the lower back, and progressive resistance loading via built-in resistance and weight plates, and The Abs Company has built a tool that handles every ab muscle that actually matters.
Ready to add one to your current setup? Browse the full AbCoaster lineup at Strength Warehouse USA.Â
[1] Stenger, E. M. (2014). Electromyographic comparison of a variety of abdominal exercises to the traditional crunch. University of Wisconsin-La Crosse Graduate Studies. Click Here For Referenced Article.
[2] Bruš Papročki, M., et al. (2022). Electromyographic comparison of an abdominal rise on a ball with a traditional crunch. International Journal of Environmental Research and Public Health, 19(5), 3012. Click Here For Referenced Article.
Joe leverages over 20 years of intense workout experience and six years in the fitness industry. As a former collegiate football player, Joe knows what it takes to stay in peak physical condition. He's dedicated to providing straightforward, expert advice on setting up home gyms, personal training spaces, and commercial facilities. Balancing his passion for fitness with being a devoted family man, Joe’s rigorous full-body and metcon workouts exemplify his commitment to staying strong and being a role model for his kids and customers alike.
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