In the '80's when I was young and stupid I played an Ibanez Studio Bass that weighted a ton (or so it felt) plus I played with a long strap so I was playing straight arm style (I thought I was a punk rocker even though I was playing Country LOL ) After a couple of months I developed a muscle disorder (I was playing 5 nights a week, 5 sets a night), the neck/shoulder muscle on my right side, opposite of the strain suddenly cinched up and wouldn't relax..... and it hurt. I remember having to have friends drive me to and from work 'cause I couldn't drive, and at work sitting on a stool. Very embarrassing for the heavy rocker I thought I was. So I switched back to a Fender Jazz, and REALLY shortened my strap (so it hung where it would be if I was sitting in a chair and it was on my lap. The pain went and then the stiffness went and with lighter Basses and shorter straps they have never come back.
Just sayin'
Just sayin'

so if you don't like us askin just ignore us.!!! enjoy your fridge!
) and I have done 5 set, 6 night a week gigs with a '74 P Bass that weighed over 12 lbs and it never seemed to bother me. But that's just me and YMMV.