How can I build muscle if I work as a packet handler 4 hours stright?
gratefulness
Answers: Best weight to build muscle *is* to raise heavy things, and your inkling is right - it's best to hold a day of rest inbetween lifting to permit your muscles recover (which is the time when they in truth get bigger/stronger).
Of course, if it's your career, you can't really have a hours of daylight of rest :)
When we say cumbersome, we also mean heaaavy. Heavy enought that you can simply lift the mass about 12 times surrounded by a row (12 reps) before need a rest. If you can do 15 in a row, the freight is too light, and it's more close to a cardio workout than weight lifting.
Also if you're lifting indigestible things as a job, you're probably working equal muscles over and over and ignoring others - utter you're picking up things from the floor and putting them on a table - that's similar to "deadlifting" a barbell, which works out your legs. Your biceps, triceps, pecs etc aren't getting that much attention.
Check this page out - click on the muscles on the right to find exercises to work them out:
http://exrx.net/Lists/Directory.html
Good luck!