Ergonomic Positioning: The M-Position Explained
One shape to learn. Your baby’s thighs supported from knee to knee, with their knees sitting higher than their bottom. That’s the M-position, and it’s what protects developing hips and keeps weight off the spine. Once you can recognise it, you can assess any carrier in about two seconds.
The M-Position
Picture your baby from the front. Their bottom sits lowest. Their thighs come up and outward. Their knees sit higher than their bottom. Trace the outline — down one leg, up to the bottom, up the other leg — and you get the letter M.
You’ll also see it called the spread-squat, the frog position, or the jockey position. All the same thing.
The three things that make it work
- Thigh support from knee to knee. The fabric runs the full width beneath both thighs, reaching the crease behind each knee. This spreads your baby’s weight across their thighs instead of concentrating it at the groin.
- Knees higher than the bottom. Not level — higher. This flexes the hip and seats the ball of the joint deep in the socket, which is exactly the stimulus a developing socket needs.
- Legs spread comfortably. Around your body, not clamped together and not forced unnaturally wide.
Look down at your baby. Are their knees higher than their bum? If yes, you’re fine. If their legs hang straight down like they’re sitting on a narrow swing, the seat is too narrow — widen it, or use a different carrier.
Why It Matters
Babies aren’t born with finished hip joints. At birth the socket is shallow and largely soft cartilage, and it deepens over the first months as the thigh bone sits in it.
That means position influences development — and the first four to six months are when the joint is most malleable. Holding the legs straight and pressed together for long stretches during that window works against how the joint wants to form. Holding them flexed and spread works with it.
This is also why tight lower-limb swaddling — legs forced straight — is a recognised risk factor for hip problems. Same principle.
What a Poor Position Looks Like
The design to avoid is sometimes called a “crotch dangler”: a narrow strip of fabric passes between the legs and everything else hangs free.
What happens in that position:
- All the weight concentrates at the groin and lower spine instead of spreading across the thighs
- The legs hang straight and closed rather than flexed and spread
- The hip joint sits at the shallow edge of the socket rather than seated in it
- The spine is pulled straight rather than resting in its natural gentle curve
A single short session won’t harm a healthy baby’s hips. Hours a day across the months when the socket is forming is the pattern worth avoiding.
How to Achieve It in Each Carrier
| Carrier type | How to get the M-position |
|---|---|
| Soft structured carrier | Set the seat width to match your baby’s size — and re-check it every couple of months. |
| Ring sling | Pull the bottom rail snug behind the knees before tightening anything else. |
| Stretchy wrap | Spread the fabric from knee to knee rather than letting it bunch into a strip. |
| Woven wrap | Fabric wraps each thigh individually — excellent by design, depends on your tying. |
| Meh dai | Check the panel width still reaches knee to knee as they grow. |
Setting the seat width once and never touching it again. A seat set for a newborn is far too narrow by six months, and the knee-to-knee support quietly disappears without anyone noticing.
Re-check every couple of months. The fabric should still reach the crease behind each knee.
Newborns: Narrower, Not Wider
One point that catches people out — wider is not better. Forcing a very small baby’s legs unnaturally far apart is its own problem.
Narrow the seat for a newborn. You’re aiming for a natural, comfortable spread, not maximum spread.
The Spine, Briefly
A newborn’s spine has a gentle natural curve — a soft C-shape. It straightens gradually over the first year as they develop head and trunk control.
A good carrier supports that curve against your body rather than forcing the back straight or letting it collapse into a deep slump. That’s the “supported back” part of T.I.C.K.S., and it’s the same check.
Recognised Guidance
The International Hip Dysplasia Institute publishes clear photographic guidance on healthy carrying positions and runs an acknowledgement programme for products that support them. If you want to see the difference rather than read about it, that’s the reference worth two minutes of your time.
Knees higher than bottom, thighs supported knee to knee — checked each time, and re-checked as they grow.
Go Deeper
- Baby carriers and hip dysplasia — the full picture, including what to do if your baby is diagnosed
- How to wear a baby carrier — getting the fit right in each type
- Types of baby carriers — how each type handles positioning
- Front-facing carriers — the position where hip support is hardest to maintain
This page is educational and is not medical advice. If your baby has been diagnosed with hip dysplasia, is in a harness or brace, or you have any concern about their hips, speak to your paediatrician or paediatric orthopaedist — and take your carrier with you so they can check the fit directly.