Can you stand up from sitting on the floor?

No hands.

I taught a matwork pilates class recently to a group of friends and to end off the class, I had asked everyone to come into a low squat from a sitting position. To my slight amusement, many people had trouble doing it and I was told it was the hardest “move” of the class, although not meant to be a “move” at all. It was simply a way to transition to standing.

Friend #1 tried to rock forward repeatedly but was stuck.

Most of us are like friend #1. Just. can’t. get. up. Baffled, she asked “Why?”

Friend #2 used a little bit of momentum (and grit) to find her way up.

Meanwhile, friend #3 found an alternative, an easier way - by pushing through the lateral borders of the feet with legs crossed. Still baffled, friend #1 asked “Why?”

To answer friend #1’s question, let’s have a look at the phases of the sit-to-stand movement.

(Caruthers et al., 2016)

When you are seated, your centre of mass is around the belly button. Before even getting up, the centre of mass needs to move forward to be above your body’s base of support, i.e. your feet. Otherwise, you would feel quite imbalanced. The first phase of sit-to-stand therefore involves trunk flexion momentum to get to the second phase of momentum transfer. Once that achievement has been unlocked, the centre of mass can move upwards as you go for seat-off and straighten your legs.

Now back to the trio of friends and the context of getting up from the floor, instead of a chair.

After bending the knees, friend #1 had limited space for trunk flexion. There was only so far that she could lean forward before her chest was blocked by her knees.

Friend #2 tried a little harder, activating her core and hip extensors so much that she managed to move her centre of mass far enough forward to balance herself in a squat. Friend #2 likely also had better ankle mobility in that her ankle dorsiflexion allowed her shin to get closer to her foot, thereby facilitating the centre of mass transfer as well.

Friend #3 kept her legs crossed and therefore could lean her trunk much further forward than the other two. And up she went!

Reference

Caruthers, E.J., Thompson, J.A., Chaudhari, A.M., Schmitt, L.C., Best, T.M., Saul, K.R., & Siston, R.A. (2016). Muscle Forces and Their Contributions to Vertical and Horizontal Acceleration of the Center of Mass During Sit-to-Stand Transfer in Young, Healthy Adults. Journal of applied biomechanics, 32 5, 487-503 .