Depending on the caliper release it can be very difficult to shoot with back tension. Releases with long travel triggers are notoriously bad for this. With back tension there is normally very little movement (as you saw in the video) from anchor to release. If your trigger travel is too long then you are all out of movement before the release fires, leading to punching the trigger. TruFire releases tend to be some of the worst offenders.

What you want is a release that breaks with little or no trigger travel (TruBall Short-N-Sweet, Carter 2 shot, etc...). As you apply BT you load up on the trigger until it releases.