No danger with angling your elbow, if it feels good, your body can take it.
As for feeling it in the forearms, the brachioradialis does elbow flexion alongside the biceps and brachialis. Doing reverse grip curls with ez bar burns the brachioradialis pretty hard in my experience.
Also, try doing smaller jumps if you can, does your gym not have 1.25kg plates?
Nah, it’s a new, small community kinda gym, I actually have nagged them but because DBs over 15kg had fricking 5kg increments, but I always thought 2.5kg was fine for progressively overloading
Also I want to minimize branchioradialis involvement, they grow like weed and make my forearms look very disproportional
Nah, it’s a new, small community kinda gym, I actually have nagged them but because DBs over 15kg had fricking 5kg increments, but I always thought 2.5kg was fine for progressively overloading
2.5kg is fine for compound exercises, but smaller muscles don't grow stronger that quick, it's especially noticeable on movements you can't cheat to compensate.
Also I want to minimize branchioradialis involvement, they grow like weed and make my forearms look very disproportional
What sort of unicorn are you? Alongside calves they're the most stubborn muscles I got.
Stay away from pronated grip in that case, do curls in supinated position. Try out incline dumbbell curls or bayesian curls and see how those feel, personally I never feel it in my forearms on those, other than grip sometimes.
There is tension on the forearm muscles at the bottom of a preacher curl from the stretch, and an isometric contraction as you keep your hands fixed while curling the bar. If you're flexing your wrists during the curl you may even be doing a wrist curl inadvertently as well.
I can't say whether putting elbows out is unsafe or not, but if it's putting your biceps in a more advantageous position to lift more weight it's probably not worth it. Remember that your muscles only care about tension, not the actual weight you're using. There's no reason to adjust your positioning to lift more weight - use the weight and position that maximizes the stretch and tension on the muscle you're targeting for your set and rep targets. No reason to make it easier just to lift more weight if your goal is hypertrophy.
I did that because I have been having trouble progressing, I can do like 15 reps but as soon as I add 5kgs, I suddenly am struggling to do a single rep
If you can't add weight, keep adding reps. Studies show that rep ranges anywhere from 5 to 30 reps can be just as effective. And buy some smaller plates if it helps. Adding 5kg to an exercise like a bicep curl is a significant jump. I have 1kg and 0.5kg micro plates for that reason.