Passive gastrocnemius stretch with towel under the knee (Gastrocnemius stretch, with assist, towel under knee, supine)

Lie on your back with your legs straight out in front of you.
Ask your assistant to place a small rolled up towel under the knee of the leg you would like to stretch.
This is to protect your knee whilst the stretch is being performed.
Ask your assistant to use their hand or their body weight to push your ankle up towards you.
You should feel a stretch in your calf muscle.
Hold this position, relaxing as much as possible.