In a conventional deadlift, the knees and hips should lock out at the same time and what we want to see is the knee action stays forward and never recedes until the bar needs to pass it. Whenever we see those knees recede early, that means the quads are shutting off...what you want to see is when you're pulling, those knees never shift back. They always stay forward until the bar clears and the hips and knees lock out at the same time.