If it's been a while since you hauled the 50kg bags and now don't want to carry 40 you could just be unfit/unconditioned. If you have been routinely carrying 50kg and now it's hard maybe you are getting old/feeling the effects if wear and tear XD

I remember my dad complaining about how he was getting old because once upon a time he was able to climb up and down the ladder with a coil of lights over each shoulder when decorating his house for Christmas, and now that he's much older he's struggling to carry one.

Glad you were able to squeeze your way through the recent growth to get down to the river, the shots are nice! I guess your fishing spots aren't so popular otherwise there would be a trail XD