Bryan had some good observations.
Here are a few tips.
You need to get in your start position and pause for a second. Make sure you...
-have your weight back on your heels, not the balls of your feet.
-have your knees flaired so that your hips can sit in a bit more- get that butt down a tad.
- get your chest up/shoulders back- part of the problem is you are looking down at the floor, you want to look straight ahead. Arch that lower back.
- you are shooting your butt up right away which is changing your back angle so that you are completely over the bar, and your legs are straightening, which is causing the bar to full you forward, which is causing you bar to swing around. See attached picture with your position compared to the other picture. Your legs are nearly straight, your back is a tad rounded, and your shoulders are facing the floor, rather than being back.
When leaving the ground you want to try to drive through the heels and lead with the chest. This will help keep that back angle the same off the floor, as well as keep that bar close.
So there are a lot of technical things going on that will likely be corrected if you adjust a couple things, so my immediate advice would be to REALLY REALLY REALLY focus on (then you can work on this and post a new video):
Getting a good start position (also see pictures I will post in follow up post below), with your weight on your heels, shoulders back, looking straight ahead, nice set back.
Leaving the ground by driving through your heals, pushing through the floor, and leading with your chest not butt. Keep that bar nice and close... it should move right up along your thighs up to your hips before pulling under the bar.
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