You’re a smart guy. Go ahead and peruse the mountain of research in favor of actually lifting the weight instead of strapping one's self into a machine that does the stabilizing work for you. And for bulging disks? The number one culprit there would be the fancy leg press machine that people love to load up with weight to impress gym goers as it puts ungodly amounts of pressure on the discs of your lumbar.
The Director of Human Performance at Nike uses the hex bar deadlift to help Olympic level athletes - from sprinters to marathon runners- to increase their speed.
Finally, got back pain? Most likely it’s because your back is stiff and weak.