Building a truly advanced core requires more than endless crunches and planks.
Top hybrid athlete Alec Blenis has cracked the code with four brutally effective exercises that target every angle of your midsection.
In a recent YouTube video, Blenis walks through his go-to movements for sculpting serious abdominal strength—complete with technique cues that separate mediocre results from transformative ones.
Whether you’re chasing a defined six-pack or bulletproof functional strength, these exercises will push your limits.
Jump to:
- The GHD Sit-Up: Master the Foundation
- Reverse GHD Sit-Up: The Upper Ab Destroyer
- Cable Twist: Oblique Power Development
- 45-Degree Side Bend: Complete Oblique Development
- Programming These Exercises for Maximum Results
- Common Mistakes That Sabotage Results
- Nutrition and Recovery for Core Development
- Integration With Full-Body Training
- Building Sustainable Core Strength
The GHD Sit-Up: Master the Foundation
Blenis kicks off with the GHD sit-up, a staple in CrossFit boxes and serious strength facilities worldwide. But executing this movement properly makes all the difference between wasted effort and measurable gains.
The key lies in lumbar positioning. Your lower back should press firmly into the pad, creating a stable base from which to move. Too many athletes position themselves incorrectly, robbing the exercise of its effectiveness.
Instead of lifting with your head or chest, focus on bringing your ribs towards your pelvis.
This cue transforms the movement from a momentum-driven swing into a genuine core contraction.
Breathing and Weight Progressions
Blenis emphasizes coordinated breathing: expand your rib cage with a deep inhale on the descent, then crunch upward with a controlled exhale. This respiratory pattern enhances intra-abdominal pressure and core stability.
For athletes ready to level up, adding weight creates exponential difficulty. Hold a dumbbell or plate at your collarbone—never throwing it, always controlling it through the entire range of motion.
Beginners should start with bodyweight only, focusing obsessively on form for 2-3 sets of 10-15 reps. Advanced athletes can push toward 3-4 sets of 15-20 reps with added resistance.
Reverse GHD Sit-Up: The Upper Ab Destroyer
Next comes what Blenis calls one of the most challenging core exercises in existence: the reverse GHD sit-up. This movement flips the script entirely, targeting upper abs and respiratory muscles with punishing intensity.
Positioning is critical. Lie back with your upper back supported and legs hanging down. The movement initiates by drawing your knees toward your elbows—not by swinging or using momentum.
Focus on a slow and controlled eccentric phase, lowering your legs gradually.
That negative portion is where strength gets built. Rush it and you’ve wasted the rep.
Scaling Options and Advanced Variations
Most machines allow support adjustments to make the exercise more manageable for beginners. Start there—there’s zero shame in meeting yourself where you are.
Aim for 2-3 sets of 5-10 reps initially, prioritizing quality over quantity.
Advanced athletes can extend their legs straight, dramatically increasing the eccentric challenge. Blenis even mentions the GHD dragon flag variation for those seeking maximum suffering and maximum results.
Target 3-4 sets of 8-12 reps once you’ve mastered basic mechanics.
Cable Twist: Oblique Power Development
Blenis transitions to rotational strength with cable twists, an exercise that builds both oblique definition and functional core stability. But setup determines everything.
Position yourself at a 45-degree angle to the cable machine. This angle maintains constant tension throughout the movement, making even the stretch position challenging. Stand perpendicular and you’ll feel slack at certain points—a waste of each rep.
Focus on a big stretch at the start and twist across your body, maintaining control and tension.
Explosive vs. Heavy Training Protocols
Blenis advocates two distinct approaches depending on your goals.
- Explosive training: Use moderate weight with faster, more powerful movements to prepare your core for real-world forces. Think 3-4 sets of 10-15 reps.
- Heavy strength work: Load up the weight and grind through 3-6 reps per set, building raw rotational power.
Both methods deliver results, but mixing them across training cycles prevents adaptation and keeps progress coming.
45-Degree Side Bend: Complete Oblique Development
The final exercise in Blenis’s arsenal targets obliques, lower back, and hips through lateral flexion. The 45-degree side bend might look simple, but proper execution separates amateur hour from professional results.
Body positioning matters immensely. Place yourself on the bench at a 45-degree angle, ensuring a large range of motion from full stretch to complete contraction.
Hand placement offers built-in progression. Start with hands at your sides for 2-3 sets of 10-15 reps. Once that becomes manageable, move hands behind your head. From there, progress to overhead variations for maximum difficulty.
Start with hands at your sides, then progress to hands behind your head or overhead for increased difficulty.
Advanced athletes should aim for 3-4 sets of 15-20 reps, adding weights when bodyweight becomes insufficient stimulus.
Programming These Exercises for Maximum Results
Throwing random core exercises into your routine won’t cut it. Blenis’s four movements work synergistically when programmed intelligently.
Consider organizing them as a dedicated core session 2-3 times weekly, or distribute them across your existing training split. The anterior chain gets hammered by both GHD variations, while cable twists and side bends develop rotational and lateral strength.
Recovery matters just as much as execution. Your abs are muscles like any other—they need stimulus, then rest to adapt and grow stronger. Crushing core work daily often produces worse results than strategic programming with adequate recovery.
Tracking Progress and Making Adjustments
Document your weights, reps, and sets religiously. Progressive overload applies to core training just as it does to your squat or bench press.
If you completed 3 sets of 12 GHD sit-ups with a 10-pound plate last week, aim for 13 reps or 15 pounds this week. Small increments compound into dramatic transformations over months.
Listen to your body’s feedback. Lower back discomfort might signal technique issues rather than normal training stress. Video your sets, compare them to Blenis’s demonstrations, and make corrections before minor problems become major injuries.
Common Mistakes That Sabotage Results
Even with perfect exercise selection, execution errors destroy potential gains. Blenis’s cues help prevent the most common pitfalls.
Rushing through reps tops the list. Core training demands controlled tempos, especially during eccentric phases. Each rep should take several seconds—not fractions of a second.
Using momentum instead of muscular contraction wastes everyone’s time. If you’re swinging, bouncing, or jerking through movements, reduce the difficulty until you can maintain strict form.
Another frequent error: neglecting breathing patterns. Proper respiration enhances core stability and power output. Hold your breath throughout a set and you’re leaving performance on the table.
Equipment and Setup Considerations
Not every gym stocks GHD machines or 45-degree benches. If you’re working with limited equipment, modifications exist.
- No GHD? Decline bench sit-ups provide similar stimulus, though range of motion suffers slightly.
- No cable machine? Resistance bands anchored securely replicate the twisting movement pattern.
- No 45-degree bench? Standard side planks with movement add lateral flexion work.
Perfect equipment helps, but determined athletes find ways to adapt. Focus on movement patterns and muscle actions rather than specific machines.
Nutrition and Recovery for Core Development
Blenis’s exercise selection provides the training stimulus, but visible abs require low body fat—and that comes down to nutrition more than any exercise protocol.
No amount of GHD sit-ups will reveal definition if your diet doesn’t support fat loss. Create a moderate caloric deficit, prioritize protein intake around 0.8-1 gram per pound of bodyweight, and be patient with the process.
Sleep quality directly impacts both recovery and body composition. Aim for 7-9 hours nightly, maintaining consistent sleep and wake times even on weekends.
Hydration supports performance and recovery while helping regulate appetite. Drink enough water that your urine runs pale yellow throughout the day.
Integration With Full-Body Training
These core exercises don’t exist in isolation—they complement and enhance your compound lifts and athletic performance.
Stronger abs mean heavier squats and deadlifts. Improved rotational power translates to better performance in sports requiring throwing, swinging, or change of direction.
Consider workout sequencing carefully. Exhausting your core before heavy compound lifts compromises stability and safety. Save dedicated core work for after main movements, or schedule it on separate training days entirely.
Athletes training twice daily might tackle these exercises during a second, lighter session focused on accessory work and mobility.
Long-Term Progression Strategies
Blenis’s four exercises provide years of progression potential through systematic manipulation of training variables.
Beyond adding weight or reps, experiment with tempo variations. A 5-second eccentric on GHD sit-ups creates entirely different stimulus than standard tempo.
Pause reps—holding the contracted position for 2-3 seconds—build additional strength and control. Cluster sets with short rest periods increase total volume while maintaining high quality.
The strongest athletes periodize their core training just like other muscle groups, cycling through strength phases, hypertrophy blocks, and power-focused periods.
Building Sustainable Core Strength
Blenis delivers a masterclass in advanced abdominal training through these four carefully selected exercises. Each movement targets different aspects of core function—from anterior flexion to rotation to lateral stability.
The real magic happens when you execute them with precise technique, program them intelligently, fuel recovery properly, and track progress consistently. That combination separates weekend warriors from elite performers.
Start where you are, apply the scaling options Blenis provides, and commit to the process. Core development takes weeks and months, not days—but the functional strength and aesthetic results make every challenging rep worthwhile.
