Core Training for Clients: Beyond Crunches to Real Function

Most clients walk into their first session with a mental image of core training that looks like a floor full of crunches and maybe a few sets of bicycle kicks. They want a “flat stomach.” They’ve been told by every fitness magazine they’ve ever read that the abs are the key to everything. As their trainer, your job is to respectfully dismantle that framework — and replace it with something that actually works.

Core training for personal training clients is one of the most misunderstood areas in the industry. Done right, it builds the stability, force transfer, and injury resilience that makes every other movement in their life safer and more powerful. Done wrong — meaning isolated, spinal-flexion-dominant, low-load ab circuits tacked onto the end of a session — it produces almost none of those benefits and puts certain clients at unnecessary risk.

This article gives you a working framework: what the core actually is anatomically, how to categorize the function you’re training, which exercises to prioritize for different client types, and how to build progressive overload into a system that most trainers treat as an afterthought.

What the Core Actually Is (And Why It Matters for Programming)

The word “core” gets thrown around loosely, so let’s anchor it to anatomy. The core is not the rectus abdominis. It is the cylindrical system of muscles that surrounds the lumbar spine and pelvis — above, below, and on all sides. That includes the diaphragm (top), the pelvic floor (bottom), the transverse abdominis and multifidus (deep stabilizers), the internal and external obliques, the erector spinae, quadratus lumborum, and to a functional extent, the hip flexors and glutes.

This system has one primary job: manage intra-abdominal pressure and control the position of the lumbar spine under load, during movement, and in anticipation of perturbation. The classic work from researchers like Stuart McGill has made clear that the spine’s stability comes not from any single muscle contracting hard, but from the coordinated, stiffening action of the entire cylindrical system working together. That’s a fundamentally different training stimulus than crunching your way through three sets of twenty.

When you understand the core as a pressure-managing, spine-stiffening system, your exercise selection shifts automatically. You stop asking “how do I work the abs?” and start asking “how do I train co-contraction, anti-movement, and load transfer?” Those are the questions that produce real-world results.

The Three Categories of Core Function

Organizing core exercises by function — not muscle — is the most practical framework available to working trainers. There are three categories worth building your programming around.

Anti-extension refers to the core’s ability to prevent the lumbar spine from hyperextending under load or gravity. Plank variations, ab wheel rollouts, and dead bugs all live here. This is the most commonly undertrained category and the most directly relevant to low back health. When a client’s lumbar spine collapses during a squat or deadlift, anti-extension endurance is usually part of the problem.

Anti-rotation refers to resisting rotational forces at the spine — particularly relevant during unilateral loading and any movement where the hips and shoulders aren’t moving symmetrically. Pallof press variations, single-arm carries, and half-kneeling cable chops are your primary tools. This category is critical for athletes but equally important for general population clients who carry groceries, shovel driveways, or sit asymmetrically at a desk for eight hours a day.

Anti-lateral flexion is the core’s ability to resist side-bending. Suitcase carries, lateral plank variations, and single-arm overhead holds train this quality. The quadratus lumborum and lateral obliques are primary contributors here, and weakness in this pattern shows up fast in clients with a history of lateral hip pain or those returning from unilateral lower body injuries.

A well-designed program cycles through all three categories. Most untrained clients will have significant deficits in anti-rotation and anti-lateral flexion because nothing in their daily life has ever asked those systems to work hard.

Programming Core Training for Different Client Goals

The framework shifts depending on what your client is actually trying to accomplish. Here’s how to differentiate without overcomplicating it.

General population clients focused on health and longevity need a foundation of anti-extension endurance and basic bracing mechanics before anything else. Start with dead bugs, bird-dogs, and modified planks. Teach them what bracing actually feels like — rib cage down, mild posterior pelvic tilt, breath held at roughly 70% capacity to generate IAP. Once that foundation is in place, introduce loaded carries and Pallof press variations. This population rarely needs anything more complex than that to see substantial benefit.

Weight loss clients often assume core training should dominate their sessions because they want a flat stomach. The honest conversation here is that body composition changes come from energy balance, not from the number of ab exercises in a workout. That said, heavy loaded carries (farmer carries, suitcase carries) provide genuine core training stimulus while also burning a meaningful amount of energy — making them a legitimate two-for-one for this population. The ACSM’s position on exercise for weight management supports prioritizing compound, multi-joint movements, which aligns with this approach.

Older adult clients need core training that translates directly to fall prevention and activities of daily living. Research on balance and falls consistently implicates hip abductor weakness and trunk lateral stability. Side-lying hip abductions, standing single-leg balance progressions, and light suitcase or waiter carries are all well-tolerated and highly transferable. Avoid loaded spinal flexion in clients with known or suspected osteoporosis of the lumbar spine.

Athletic clients or those training for sport need rotational power development on top of the stability foundation. Once anti-rotation endurance is established, you can progress to resisted rotation, cable chops, and medicine ball work. But the sequence matters — stability before power, always.

Core training and plank exercise

Exercise Selection: What to Use and What to Deprioritize

This is where the rubber meets the road for most trainers doing core training with personal training clients day to day. Here are concrete recommendations.

High-value exercises for nearly all clients: Dead bugs, bird-dogs, plank variations (with true anti-extension demand — not sagging hips, not passive hanging), Pallof press (standing, half-kneeling, split-stance), suitcase carries, farmer carries, and single-arm overhead carries. These exercises are low-risk, highly coachable, and produce measurable transfer to other lifts and daily function.

Conditionally valuable exercises: Ab wheel rollouts require the anti-extension foundation to already exist — throwing an untrained client on an ab wheel is a fast track to a painful lumbar hyperextension. Hanging leg raises demand strong hip flexor control and shoulder stability. Loaded rotational medicine ball work is excellent but requires a stable base first. Use these as progressions, not starting points.

Exercises to de-prioritize for most general population clients: High-repetition crunches and sit-ups. The spinal flexion under load argument is nuanced — it’s not that these movements are universally dangerous, but their benefit-to-risk ratio is poor compared to alternatives, particularly for clients with disc history, tight hip flexors, or anterior pelvic tilt. They’re also poor at developing the functional qualities clients actually need. The exception may be athletes who need spinal flexion strength in sport-specific contexts, but that’s a small slice of your client base.

For a broader context on functional movement selection, see our functional fitness exercises guide, which covers movement pattern selection across the major categories.

Progressive Overload for Core Training

Core training is one of the areas where trainers most commonly fail to apply overload principles — clients do the same plank for the same duration for months and wonder why they’ve stopped improving. Overload applies here exactly as it does anywhere else.

For endurance-based core work (planks, carries, Pallof press), progress through duration, distance, and load in that order. A client who can hold a plank for 60 seconds with perfect form progresses to 75 seconds before you add any external load. When load is added — a weight plate on the back, a heavier kettlebell in a carry — duration resets and rebuilds.

For strength-oriented core work (ab wheel, loaded carries, cable anti-rotation), apply a rep and load progression similar to any compound lift. Three sets of eight Pallof press reps at a given load progresses to three sets of ten before load increases. Keep rest periods deliberate — 60 to 90 seconds is appropriate for most core strength work.

Track it. This sounds obvious but most trainers keep meticulous records of squat and deadlift progression and zero records of core exercise progression. If you can’t tell a client how much stronger their anti-rotation capacity has gotten over twelve weeks, you’re leaving a significant coaching opportunity on the table. Building a full periodized approach integrates naturally with the principles covered in our article on building strength programs for clients.

For more strategies like this, subscribe to our free newsletter — thousands of trainers get weekly tips delivered straight to their inbox, covering programming, client retention, business, and evidence-based coaching practice.

Common Coaching Cues That Actually Work

Cueing the core is a skill that takes time to develop, and vague cues produce vague results. A few that consistently land with clients across experience levels:

“Brace like you’re about to take a punch to the stomach” produces genuine IAP generation in most clients without requiring them to understand the underlying anatomy. Follow it with a light fingertip tap to their lower abdomen to give them proprioceptive feedback.

“Ribs down, not chest up” corrects the compensatory rib flare that kills plank quality and anti-extension positioning in most beginners. Many clients have learned to “stand tall” by lifting their chest — you need to undo that pattern before anti-extension exercises do their job.

“Don’t let me move you” works well for Pallof press and any loaded anti-rotation drill. Give them a physical reference point — your hand against their shoulder or hip — and let them feel what resistance they’re managing.

Avoid cues that reference “sucking in” the stomach. Drawing in the navel reduces IAP and actually decreases lumbar stability — the opposite of what you want in almost every core training context.

Final Thoughts: Build Function First, Aesthetics Follow

The trainers who consistently get the best results with core training are the ones who stop selling the six-pack and start selling the back that doesn’t hurt, the deadlift that went up 40 pounds, and the ability to play with their kids without flinching the next morning. Those are the outcomes functional core training produces, and they’re far more compelling to most clients than the aesthetic promise that ab exercises rarely deliver on their own anyway.

Build your core programming around function: train anti-extension, anti-rotation, and anti-lateral flexion. Progress load and duration deliberately. Coach bracing mechanics early and reinforce them constantly. Use carries as a cornerstone exercise — they’re underused, highly effective, and clients tend to enjoy them because they feel athletic.

The crunches can stay if a client loves them and has no contraindications. But they shouldn’t be the centerpiece of your core training approach. The centerpiece should be a system that makes every other movement your clients do more stable, more powerful, and more resilient to the demands of real life.