Courage.....that's what it takes to get under the bar.
First, you will have to forgive me for the video I'm using. There's not a lot of videos out there of your local heroes unwilling to pull themselves under the bar at a heavy load. But this video is a perfect illustration of beginners or your inexperienced lifters hesitating. If you think about it it's not hard to understand why one would do something like this. Who in their right mind would try and put a shit load of weight over their heads, right? It's scary! But fear not, there are exercises out there to help remedy this problem.
The first exercise I would suggest is the drop snatch or also known as the snatch balance. This exercise focuses on dropping under the bar and moving the feet out sharp and aggressively. You will also need to focus on driving the head and chest through the arms and diving your hips back as you drop under the bar. This exercise it's self takes a certain amount of courage, but can be done with a PVC pipe or an empty bar. It is a great exercise for beginners and novices alike. And for your more experienced lifters, a great exercise under load. Depending on the athlete's ability you can practice catching the bar over head at all levels of the overhead squat.
The second exercise is the hip snatch or high hang snatch. The video that you are watching gives two variations of the same movement. The hip snatch is the third pull of the snatch and helps to open the hips, lift the chest, and then aggressively pull yourself under the bar. It will force the athlete to be aggressive and to drop under the bar fast. These are just some of the benefits of the hip snatch. It is also great exercise for beginners but will benefit your more experienced lifters as well.
Practicing these movements will help with dropping under the bar, foot work, being aggressive and opening up the hips. It will also teach you to lift the chest to pull under the bar. All things that must happen in order to hit that heavy snatch. One thing that is up to you is practicing these exercises and finding the courage to drop under that heavy load! Do you have it?