The half split yoga pose is a fantastic exercise for goalkeepers to increase flexibility throughout the hip joint, as it closely relates to movements produced while blocking in 1-on-1 situations, or making foot saves. In the images below, Joe Hart, Manuel Neuer, and Marc Andre Ter Stegan are all producing saves in a half split position. Recently I posted my own variation of a half split exercise to the TKU instagram account (https://www.instagram.com/p/CHUdxG-nTIe/ ), and I wanted to explain exactly how and why I use it.
First off, I am using sliders and a wooden floor in the video, but you can easily replicate it with any gliding surface and a towel.
Because the exercise produces lots of tension in the groin and hamstring muscles, it's important to do this after a training session or workout, and with a proper warm up and gradual pre-stretch.
Start in a kneeling position, with the heel of your front foot on the slider/towel. Firstly, straighten your knee by slowly sliding your foot out to the side away from your body. When your leg is straight, start to sit down into the stretch with your pelvis/bum moving as close to the floor as possible.
Make sure you are not sitting on top of your kneeling leg, but rather with your pelvis/bum sitting in between your legs, as far as possible in a split position. To produce an additional stretch across the ankle joint, place the foot of your kneeling leg with the top of the foot faced down to the floor, and the bottom of the foot faced up to the ceiling as much as possible. To come back up from the stretch, activate the hamstrings to slide your leg back into a kneeling position.
I usually do this stretch 2 times per week, with about 3 sets of 4-5 extensions on each side.
At first it'll feel quite uncomfortable or even a little painful, however mentally visualizing a foot save or 1-on-1 scenario as you produce the movement will make it feel more natural, and really helps you sink deeper.
From 0:22 in the video below, you will see Leno, Ben Foster, and David de Gea all produce outstanding examples of this technique from the Premier League.