Training with ropes is excellent for improving pole vault technique. The inversion drill mimics the movement on the pole and can get the vaulters used to the feeling of being upside down and improve core strength. Rope climbing is great strength training for pole vaulting.
Hold your take off position, swing the left leg nice and long to inversion (upside down) keeping the right knee up. Using your core strength you are aiming to rotate around your shoulders and not break early at the hips. The dynamic left leg adds energy to the movement and makes inversion easier during the vault.
Simple rope climbs are a good upper body strength training exercise. This can be done initially using the feet, contolling the decent back down. As they get stronger they can start to do with without using the feet, just the hands. Keeping the legs out straight whilst using just the hands contributes to the core strength.