Okay so not having heard of something isn’t a myth—it’s a mistake. (I apologize for the lithpy pun.) Anyway, neutral spine and neutral neck (or “packed neck”, as Marco calls it) are both really damn important. Proper spinal alignment is debatably the single most important training cue out there. All performance trainers, powerlifters and high level athletes know this, but most gym-goers are out of the loop. They lift with really poor spinal alignment, not because they aren’t focusing enough on form, but because they’ve never even heard that spinal alignment exists, let alone matters. You’ve probably heard not to round your back, but that’s as far as mainstream sources go on the matter. The problem here is that as ectomorphs we’re particularly vulnerable to injuries, as our structures are naturally smaller. We can fix this, of course, and your bone density and tendon strength will soon reach beastly levels, but as a skinny dude starting out you can do some real damage to yourself if you neglect your alignment.
This post will help you improve your longterm health and strength, dodge future back pain, and help you build more muscle in the short term by properly targeting the muscles you’re trying to hit.