Assuming you are a beginner…
Do three sets of eight of the following exercises.
- Squats - go down until your thighs are roughly parallel to the floor - KEEP YOUR HEAD UP
- Bench press - never bounce off your chest or arch your butt off the bench - grip should be medium, about shoulder width apart
- Pull downs (or chin ups if you are strong enough)
- Calf raises
- Upright rows
- Curls
- Leg curls
Do one set of crunch sit-ups to failure before and after your workout. Do some kind of aerobic work (cycling, jogging, stairmaster, whatever) for 20 minutes three times a week. Do some gentle, pain-free stretching AFTER every workout.
Experiment to find out how much weight you can handle so that you can get eight perfect reps on each set. The exertion should feel moderately heavy. Work at it until you can get twelve perfect reps on all three sets of an exercise. Then increase the weight 5 - 10% and go back to eight. Repeat.
Rest one minute between sets. Use perfect form on all reps, no matter what. Use perfect form on all reps, no matter what. More importantly, use perfect form on all reps, no matter what. (Get the idea?)
Use free weights. Work out on three non-consecutive days a week (Mon-Wed-Sat or Tues-Thurs-Sat).
Eat a normal, high carbohydrate, moderate protein, low fat diet. Protein powders and mega-vitamin supplements are a waste of money. A single, generic vitamin pill a day is OK, but more than that is just vitamin-fortifying your urine.
If you don’t generally wake up before the alarm goes off, you are not getting enough sleep.
The general theory is that weightlifting breaks down the muscle tissue, and rest then builds it back up a little stronger than before.
90% of what is said about bodybuilding and nutrition is nonsense from people who are trying to sell you something.
Stick to it without fail for six weeks, and re-evaluate where you are. You will be surprised.