If you were at my HUB (and probably most) you are more than a welcome relief. And hopefully, you'll stick it out and won't quit after a few days or a week.
Many new hire males are put to work loading or unloading Semi Trailers. Unloading, you hustle placing packages on belts as fast as you can. Loading, you stack boxes and Smalls (bags of small packages) in walls, wall after wall, until the trailer is almost full, then you load the E-Regs (Irregular) items. These are usually big and heavy(er) than the rest of the flow.
It can be a demanding job for new-hires, but if you stick it out, listen to your trainer(s) and follow your Supe's instruction (Supervisor), you will be fine. The muscle soreness you may experience will fade, and you will be in great shape after a few months, plus you are in a Union shop, and building seniority. I look at it as a paid workout. They are paying me to work out. How cool is that? My career job during the day involves a lot of sitting, so I enjoy working part time at UPS.
Hope you do well. I can't imagine you won't be hired. We certainly need the help.