1. Have a friend locate your C7 vertebra, the large bony bump at the back of your neck where your shoulders start.
2. Put your hands on the top edges of your hipbones with your thumbs reaching behind you. Imagine a line running across your low back between your thumbs.
3. Using a flexible measuring tape, your friend should start at the C7 vertebra and measure down your spine to the point where the tape crosses the imaginary line between your thumbs. This distance is your torso length.