Well if you haven't worked out in a while, you aren't going to be able to go to gym 4 days in a row. My suggestion is go to the gym every 2-3 days the first week or 2, doing full body routines such as:
Squat, Deadlift, Flat Bench Press, Overhead Press, Pull-ups, & Dips.
3 sets of 8 reps... after warm-up sets of 10-12 reps
Make sure you do a couple warm-up sets. First, to get used to the weight, as you won't know your limit,and also to get your muscles used to it. I would recommend starting with half the weight you think you can use for 10 reps on your first warm-up set and then adjust the weight up from there, before starting your work sets.
I'm telling you to do full body exercises for a couple reasons. If you want to put on weight these are the compound exercises you will need to do that. Isolation exercises (such as curls, flies, leg extensions, ect..) are a waist of time for gaining mass. Knowing this will save you amountless wasted time.
I'm not saying that they don't have their uses but those uses won't help you gain mass.
Also, make sure you warm up first and stretch well before starting. Your body won't take the stress well and stretching will help keep from injury and also shorten the painful recovery period.
Now after those first couple weeks you will feel your body healing faster as it gets used to the stress from weight lifting. Now, you will be able to start going 4 times a week.
Don't go 4 days in a row though... I suggest: 2 on/1 off/2 on/2 off.
Chest/Triceps
Legs/Calves
Shoulders/Traps
Back/Biceps
Well, that should get you started... good luck,
Tom
