Hey JDM
You're really not getting your back set so when you get to the bottom, it's just flexing and makes for a poor force transmitter.
Go over to our YouTube channel and check out the video called "low back position control" and watch that.
Once you learn to set your back, when you take your breath and brace the trunk, don't "crunch" down on just the abs up front. It's pulling your pelvis and taking your back out of extension.