Plank Extension Form at [solidcore]: Five Fixes That Work
By [solidcore]
Whether you're a seasoned [solidcore] athlete or a newcomer braving your first few shakes, the plank extension is one of the most deceptively challenging moves in class. At first glance, it looks simple. But the effectiveness of this low-impact, slow-tempo move hinges on micro-adjustments—and most people are doing at least one thing wrong.
Here are the top five mistakes people make during the [solidcore] plank extension, why they matter, and how to fix them to get the most out of every second.
1. Stop Leading With Your Shoulders in a Plank Extension
The Mistake:
A lot of people initiate the extension from their shoulders or arms, pushing the carriage out with only upper-body force. But your shoulders shouldn’t be doing all the work.
Why It Matters:
This mistake takes the tension away from the deepest layer of your core muscles, and transfers it to your shoulders. Not only does this reduce the core activation that makes [solidcore] so effective, but it also increases your risk of neck and shoulder strain.
How to Fix It:
Instead of thinking about pushing the platform, think about pulling your belly button in and up as you glide your arms forward. Imagine you’re hollowing out your midsection while keeping your spine stable. Use your inhale to extend and your exhale to contract, maintaining a flat back and tucked tailbone.
2. Make Sure You’re Tucking Your Tailbone in a Plank Extension
The Mistake:
Letting your tailbone tilt upward (also known as anterior pelvic tilt) is a common error that reduces core activation. Without a proper tuck, your pelvis may arch downward, pulling your lower back into the movement and reducing hip-to-ribcage connection.
Why It Matters:
This misalignment puts excess strain on your lumbar spine and decreases your core engagement. A tucked tailbone creates a stronger rib-to-hip connection, allowing your core muscles and obliques to fire properly. Without this connection, the work shifts to your back and hip flexors—reducing the effectiveness of the move and increasing the risk of injury.
How to Fix It:
Think about scooping your tailbone under and pushing your hips toward your ribs. Engage your glutes and pull your abs up and in to support the position. A neutral spine is not arched—it’s aligned. Keeping your tailbone tucked will help you maintain consistent core engagement throughout the entire range of motion.
3. You're Not Stacking Your Joints in the Base Position
The Mistake:
Unless you are intentionally amplifying based on your coach's instruction, starting or finishing with your shoulders behind or ahead of your elbows can create unnecessary tension in your joints. Many people unknowingly allow their joints to drift out of position, which creates unnecessary tension in the traps, shoulders, and neck.
Why It Matters:
Proper joint stacking is critical for maintaining stability and distributing weight evenly. When your shoulders aren’t directly over your elbows, it can overload the shoulder joint or pull tension into the upper back and neck, especially during long holds or slow reps. This also reduces how efficiently your core can support the move.
How to Fix It:
Check that your shoulders are directly above your elbows in both the starting and ending positions. Rather than focusing on a big range of motion, your priority should be to maintain proper form by keeping your tailbone tucked and shoulder blades retracted (down and away from your ears). It's okay if that means your range of motion is a little smaller!
4.Don't let your Hips Drop in a Plank Extension
The Mistake:
It’s easy to let your hips drop too low or hike up too high when your abs start to fatigue. Unfortunately, both positions sabotage the move.
Why It Matters:
Lifting the hips too high makes the move easier—but also less effective—by removing resistance from your core.
A neutral spine and level hips are essential for engaging the right muscles and protecting your back. If the range of motion is too large, this can result in less core recruitment and compensation of your lower back muscles, potentially leading to lower back strain.
How to Fix It:
Focus on keeping everything below the chest frozen still while using core and upper body muscles/joints to create the movement pattern.
Check your alignment in the mirror (many [solidcore] coaches will also cue you in real time). Your head, shoulders, hips, and heels should form a straight line. Keep a micro-bend in the elbows and engage your glutes to support your pelvis. If your hips are swaying, slow down even more and reduce your range of motion until you can stay stable.
5. You’re Moving Too Fast
The Mistake:
You’re not alone if you find yourself rushing through reps—especially when the move starts to burn. But speed is the enemy of intensity in the [solidcore] method.
Why It Matters:
The foundation of [solidcore] is slow and controlled movement. Rushing through plank extensions robs your muscles of time under tension, which is the key to building strength and endurance. Fast reps also make it easier to lose control, leading to poor form.
How to Fix It:
Count your tempo: aim to take 8-10 seconds per repetition. If your form breaks at that pace, reduce your range of motion rather than speeding up. It’s better to go halfway out with perfect control than all the way out with sloppy execution.
Bonus Tip: Breathe During Plank Extensions
Holding your breath during intense core work is incredibly common—and counterproductive. Breath helps stabilize your spine and power your movement. Inhale to initiate the start of the exercise and exhale as you contract your muscles and return to the base position. Breathing properly increases muscle recruitment and also encourages more mind-to-body connection, helping you stay mentally present and focused.
Master the Plank Extension, Master Your Core
The [solidcore] plank extension is a signature move for a reason: when done correctly, it activates your core like nothing else. But small misalignments or rushed execution can hold you back.
By keeping your shoulders and hips in line, and your tempo slow, you’ll unlock the full potential of this transformative move. Stay mindful, stay controlled, and remember: it’s not about how far you move, it’s about how deeply you engage.
Test out your plank extension skills and book a class today!