Seems I do my very best subconsciously to forget to put mobility training when describing my programming..Needless to say this should be done in every session and is perfect both during the warm up or in the end of the session.
I focus mostly on the hips and the shoulders as these tend to be the most stiff parts of my body, and I bet it’s true for most climbers. All that pulling on holds with arms and feet kind of pulls everything inwards making you crooked and rotated in the wrong direction. Why do we need to train mobility you might ask? In my opinion for two reasons; it makes you feel better and more free inside your own body and it enables you to do tricky moves such as stepping up higher, further apart and to stay closer to the wall when climbing. To stay close to the wall is very hard if your hips are too tight, the ability to keep them vertically aligned with your shoulders on both vertical to steep climbing becomes limited.
The same goes for shoulder mobility, when mantling, locking off with the hands far apart and also to protect them from injury while doing dynamic catches where the only contact with the wall might be one arm for a short while, swinging off and putting enormous strain on your shoulders. If they have good mobility as well as a balanced strength the risk of injury decreases. So doing hip- and shoulder mobility training during every session could give you huge gains in your climbing if you are stiff. I usually do 3×1-3 minutes for 1-3 hip stretching positions and it’s perfect to do this while resting between sets on the fingerboard for example. For the shoulders I do 3×30 reps of dynamic stretching (for example swinging the arms around holding a broom), and 3×1 minute of stretching muscles such as pectoralis minor, pectoralis major and the deltoids that all tend to be the bad guys in creating that crunched over look in a climber..
I do recommend looking into some instructions if you have never done any mobility training before; a good yoga teacher or functional fitness trainer can give some great advice and show the correct ergonomics for the different positions. Don’t forget that even stretching can be dangerous if done incorrectly.