Why wouldn't you do a full body workout?
Actually gym wise, I only go thrice a week. Saturday I followed my
fren's workout, but his workout concentrates on the "show" muscles,
chest and arms and shoulders. I add in squats on saturdays.
Sunday morning I go for deadlifts, bent over rows, and lunges
However, there is almost a 24 hrs break in between.... Rest time is
the time when your muscles grow and recover, not gym time.
Tues is of lighter weights because I usually go swim on Mondays,
and I don't want to over exert. However, Tues will be a full body
workout.
If you would like to go for 4 days, I would suggest you do finish
up a full body workout on mon and tues combined, wed break, then
thurs and fri combined to another full body workout.