[doopfoopdoop]

> But I don't think that dead lifts are the only way to get strong enough.

I think the key to getting strong is barbell exercises, because they can be precisely and incrementally loaded. (So you linearly progress.)

> And core strength helps prevent back pain.

Deadlifts, squats, and presses are all extremely good at developing "core" strength. Ab-specific exercises are not (they cannot be effectively loaded, and the loads are much smaller, and the spinal flexion/extension involved often aggravate existing back injury).

> chair that helps you sit up straight, and provides lumbar support.

If the chair is helping you, then you are not using your muscles and will continue to atrophy away. Lumbar support in general is not a good thing.

[mirimir]

I use free weights, sure.

But I've always preferred using lighter weights with lots of reps.