I also have problems with the lunges, am supposed to do 3 sets of 10 lunges per leg. I get through two sets with difficulty (and im not using any weights yet either, just lunges alone) and the third set I can barely keep myself upright, legs wobble and pushing back upwards is very hard.
Is weird, I can manage my daughters weight (20kg) sitting on my feet and lifting both legs up, holding them for count of five, then lowering again. I can do countless reps of this (involves me sitting or lieing on the lounge or bed with legs mid thigh and down over the edge), but I can't manage three sets of lunges (and then climb the stairs out of the gym without pulling myself up the handrail lol).
Am trying to do a few lunges each day at home to build up a little strength inbetween gym visits.
Cheers,
Dollfinn!
Be who you are & say what you feel, cause people who mind don't matter & people who matter don't mind.