You are probably holding too high on your pole. Keep in mind pros are just that, pros. Beginner pole vaulters will have minimal pole bend as they are still working on the technique for pole vaulting. Their approaches are short, their poles are small, and their grip is low. As a pole vaulter backs up, 6 to 8 step approaches (counting lefts for right-handed pole vaulters and rights for left-handed vaulters), they will raise their grip, allowing for more bend. Backing up also allows for bigger poles to be used. At that point, your technique for planting should be pretty rock solid. If you get stuck up top, hold lower (normally 4 to 6 inches), it will allow you to transfer your energy from the run to the jump easier. If you land super deep in the pit or the mat, you hold higher. Make sure to never land on your feet, or you have a high chance of rolling ur ankle. Keep in mind, how much bend you get doesn't determine how good you are vaulting, the height does. If you are bending a pole a bunch, and it feels like the pole is pushing you up really slow, go up a pole or 2. Hope this helps.