Do you need direct ab work, or do compound lifts cover it?
Squats and deadlifts load your trunk far more than most people assume, but they train it mainly as an isometric brace, so a couple of sets of loaded, moving ab work per week is still worth adding if you want the muscle itself to grow. Whether those abs are visible is a body-fat question, not a training one.
The idea that squats and deadlifts already train your core isn’t marketing. A systematic review of EMG across dozens of exercises found free-weight lifts — heavy back squats especially — produced the highest recorded activity in the rectus abdominis, external obliques and erector spinae, beating most dedicated core exercises. A heavy squat is a serious anti-flexion task, and your trunk does the work of not folding.
Activation isn’t a growth stimulus, though. In a separate lab comparison, squats and deadlifts at 80% of 1RM spiked the lumbar erector spinae but produced no more lower-abdominal or oblique activity than a bodyweight superman or side bridge. Under a bar, the abs work isometrically at a length that barely changes. That builds stiffness and bracing skill. It’s a thin stimulus for size, which responds better to loaded work through a range of motion.
The gap nobody mentions: the trial that would settle this — compounds alone versus compounds plus direct ab work, measuring actual muscle thickness — hasn’t been run. What exists is mechanism plus indirect evidence.
The performance claims are softer than you’ve heard
A 2023 meta-analysis of 21 studies found core training improved balance substantially and jumping moderately, but throwing and hitting velocity didn’t reach significance. An earlier Sports Medicine review was blunter: targeted core stability training gives marginal benefits to performance, with conflicting results and no standardized measurement. Most subjects were untrained or youth athletes, where nearly anything works. If you already squat heavy, the return on more planks is small.
Planks cap out, and visible abs are a diet question
A plank progresses by adding seconds, and past a minute or two you’re mostly training patience. Loaded, dynamic work — weighted and cable crunches, hanging leg raises, ab wheel, heavy carries, anti-rotation presses — progresses like every other lift, which is what growth needs.
The six-pack itself isn’t a training variable. Six weeks of ab work, five days a week, seven exercises, moved abdominal fat by nothing; it only improved curl-up endurance.
Two sessions a week, one or two loaded movements, 8–15 reps, add weight over time. That’s the whole prescription.