I'm a huge fan of adrenaline too but as I get older self preservation has become a more prominent concern. There have been too many moments in my life that were too close to call and a few where the payoff didn't happen. After those failed gambles I had to spend the next years trying to regain my mobility and get back in shape again. Though only anecdotal runners/lifters high is a much more sustainable lifestyle choice.

Tip: If you do strength training, stay away from the bar. Yes, the traditional "big 3" all involve a bar, but there are safer alternatives using dumbbells. While dangerous technique is probably possible in any exercise, my personal experience is that it's easier to fuck up and hurt yourself using a bar.

I have the impression that there's' a trade-off between effectiveness and safety though, and this advice is pretty far towards the safe side of the spectrum.

I can only recommened the opposite: if you are doing strength training by all means use mostly barbells and stick to the big 3 (some sort of press, a squat and a deadlift variations). I hurt my back, shoulder and knees doing various machines and dumbbell variations over the last 15 years, the fear in regards to lifting heavy with barbells usually stems from horrible technique, most people do not realize that lifting is a sport that needs to be learned, it's not enough to just "push the weight".

How did you hurt yourself on machines/dumbbells? Not rhetorical - I would like to avoid doing the same mistakes.

And yes, I do have horrible technique. And since I don't have a personal trainer, no one is ever going to tell me when my technique slips, so I'd rather not rely on it.

You can improve your technique a lot by carefully watching Mark Rippetoe's Starting Strength DVD. Ask someone to record video of you lifting every now and then and get a feel for your body in space or upload it to youtube for advice if you're unsure.

Mostly by overstretching particular joints under load, eg. behind the neck presses and pulldowns & pushing myself on dumbbell presses with weights I could move but barely control, at one point I lost control but did not drop the weights.

The others where loading up machines with weights I could not have moved if it weren't for the fixed movement plane of the machine, that ultimately meant trouble for my lower back (leg press) and grinding in my knees (leg extensions).

btw, most personal trainers are horrible at teaching proper technique. I'd recommened the books written by Marc Rippetoe and Bill Starr and watching videos by powerlifting coaches and lifters (that do not focus on lifting in gear). I could 'fix' (read: strengthen and work around) my back troubles with deadlifting, but would not recommened that to someone without a guide or knowledgeable help at hand.

I definitely recommend the opposite. I've found that machines often force me into a pattern of movement that may not jibe with my body mechanics or build.

I'd recommend doing the big 3, but starting off light. Focus on improving the movement. Record yourself, fix your form, develop awareness of your body position (for example - what does "butt tucked in" feel like?) and learn how to dump the bar if something goes wrong.

Above all: don't let your ego get in the way. There's a fine line between "just one more" and "one too many".

For what it's worth, I've had the opposite experience and never fail to tweak my back when using dumbbells.

Barbell training is quite safe if you learn proper technique.

Also, if strength is a goal, it's very difficult to work with heavier weights without a bar.