Core technique: hollow body, bracing and shoulder blade control

Two people can both do 10 push-ups and get very different results. One lowers until the chest nearly touches the floor, body straight as a board, shoulder blades gliding smoothly. The other sags at the hips, stops halfway and hikes the shoulders up to the ears. A few months later the first is clearly stronger, while the second has stalled — or started to feel it in the shoulders and lower back.

This is part 4 of Calisthenics 101. It covers the technique that carries over to almost every bodyweight exercise: the hollow body position, bracing and breathing, shoulder blade control, full range of motion, tempo, and filming yourself to check your form. Get these right and every harder exercise you meet later becomes easier to learn.

01 The hollow body: the shape behind everything

The hollow body is a slightly curved, boat-like shape: ribs pulled down, pelvis tucked so your lower back doesn't arch (a posterior pelvic tilt — think of drawing your pubic bone up toward your belly button), abs and glutes both tight. Lying on your back, the easiest sign is that your lower back stays pressed into the floor.

Why it matters: it's the same trunk shape you use in a lot of other exercises. A plank is a hollow body on your forearms, and a push-up is a plank that moves. Handstands, pull-ups and the front lever later on rely on the same tension. Learning the hollow on the floor prepares you for all of them.

Learning it step by step

The app's Hollow chain follows exactly this order, each step lengthening the lever a little:

1. 01Dead bug: lie on your back and extend opposite arm and leg while your lower back stays on the floor. It teaches you to lock the lower back while your limbs move.
2. 02Tuck hollow hold: lift your shoulders, pull your knees toward your chest, lower back still down. The short lever makes it easier to hold.
3. 03Hollow hold: arms straight overhead, legs long. The longest lever, so the hardest.
4. 04Hollow rock: rock back and forth without letting the shape break.

The rule: the position matters more than the difficulty. When your lower back starts to lift off the floor, raise your legs higher, bend your knees or bring your arms toward your hips. A clean 20-second tuck hold is worth far more than a full hollow hold with an arched back.

02 Bracing and breathing

Bracing isn't sucking your stomach in. Imagine someone is about to poke you in the belly: the muscles all around your trunk — front, sides and lower back — tense together like a stiff cylinder. That's the brace you want in planks, push-ups, squats and anything else that needs a solid trunk.

You don't need a maximal brace all the time. For a bodyweight squat, brace just enough to keep your back neutral; for a hollow hold or plank, brace harder. What matters is that you can still breathe while braced.

How to breathe

• Rep-based exercises: breathe in on the easier phase (lowering) and out on the effort (pushing or standing up). Don't overthink it — just don't hold your breath through the whole set.
• Holds: take short, steady breaths while keeping the brace. If you have to hold your breath to stay in position, the exercise is too hard for you right now.
• Before each set: breathe all the way out, pull your ribs down, then brace. This keeps your ribs from flaring, one of the most common faults in hollow holds and planks.

03 Shoulder blade control

Your shoulder blades aren't fixed in place; they glide over your rib cage in several directions. Many shoulder problems in bodyweight training come from shoulder blades that get stuck in the wrong position or move without control. These four movements are the starting point:

In a push-up, let your shoulder blades move naturally: they come together as you lower and spread apart as you press up. At the top, push the floor away a little more so your upper back rounds slightly — that's protraction. Common mistakes are pinning the blades together for the whole set or, the opposite, letting your chest sink between your shoulders in the plank position.

In prone back exercises like the prone Y-T-W, the order flips: pull your shoulders down, squeeze the blades together, then lift your arms. If your neck and upper traps tense up, you're probably shrugging instead of using your upper back. These exercises are also good preparation for pulling — see part 8 on pull-ups.

04 Full range of motion

Range of motion is how far a joint travels in each rep. Half reps make the numbers look better, but the muscle only works through that short range. You also can't compare sessions, because every "half" is a little different.

A few simple standards:

• Push-up: chest to about a fist from the floor, then up until your arms are straight (without snapping the elbows into lockout). Body straight from head to heels.
• [Squat](/exercises/squat): as deep as you can while your heels stay down and your back stays neutral. Knees follow your toes; knees going slightly past the toes is normal.
• Single-leg work like the [reverse lunge](/exercises/reverse-lunge): back knee down to just above the floor, then stand all the way up.
• Holds: time from when you are in the correct position until the position starts to break, not until you collapse.

If you can't do the full range yet, don't shorten the movement — step back to an easier exercise in the chain. A full-range knee push-up beats a half-range push-up. That's why each movement group in the app is a chain from easy to hard, as covered in part 2.

05 Tempo: slow and controlled

Fast isn't the same as good. When you rush, momentum and the bounce at the bottom do the work instead of your muscles, and that's exactly when form falls apart. A good tempo for beginners:

• Lower with control — you should be able to stop at any point if you wanted to.
• Don't bounce at the bottom; pause briefly if you need to.
• Come up firmly while keeping the same body shape.

That's why the app counts on the beat: each push-up or squat takes a fixed number of beats, so it's hard to cheat by rushing. If the default beat feels too fast, lower the BPM in Settings — the lower the BPM, the slower each rep. Training slower is also a way to make an exercise harder without adding weight; part 5 goes into that.

06 Quality over quantity

Treat every rep as skill practice, not just a number. A rep counts only when it has full range, the right body shape and a controlled tempo. When form starts to break — hips sagging, shoulders shrugging, range getting shorter — the set is over.

One good rep is worth more than three rushed ones.

In the app, when you can't do another rep with clean form, tap Stop. The app records how many reps you actually did and uses that to adjust your next session. Honesty matters here: if you grind out the full count with poor form, the app keeps making things harder based on reps that didn't really count.

That doesn't mean every set should feel easy. Productive sets usually end with about 1–3 reps left in the tank — the reps-in-reserve idea from part 3. Train close to the limit of your strength, but not past the limit of your technique.

07 Film yourself

What you feel often doesn't match what you're doing. Plenty of people are sure their body is straight until they watch the video and see their hips sagging. Filming is the cheapest and fastest way to get an outside view.

1. 01Prop your phone on a chair or shelf at about hip height, 2–3 metres away, so your whole body is in the frame.
2. 02Film from the side for push-ups, planks, hollow holds and glute bridges: it shows your body line and range of motion.
3. 03Film from the front or at 45° for squats and single-leg work: it shows whether your knees cave in and whether both sides match.
4. 04Record the whole set, including the last reps — that is when form usually breaks.
5. 05Watch it back in slow motion and compare it with the 3D demo in the exercise library.

What to look for:

• Hips sagging or piking in push-ups and planks.
• Head dropping or craning — it should stay in line with your body.
• Elbows flaring straight out; around 45° from your torso is usually kinder to the shoulders.
• Shoulders creeping toward your ears in prone back exercises.
• Knees caving in or heels lifting in squats.
• Range of motion shrinking over the last few reps.

08 Key takeaways

• The hollow body — ribs down, lower back not arched, abs and glutes tight — is a trunk shape you reuse in many exercises.
• Bracing means tensing all around your trunk, not sucking in; you should still be able to breathe.
• Move your shoulder blades at the right time: spread at the top of a push-up, squeezed together and down in back exercises.
• Always use full range; if you can't, step back an exercise rather than shortening the rep.
• Keep a controlled tempo with no bouncing, and end the set when form starts to break.
• Film yourself regularly to see what you can't feel.

Once your technique is solid, the next question is how to keep making exercises harder when all you have is your body. That's part 5: progressive overload. If you'd rather start training now with the app counting for you, head to the workout.