Switch mainly to machine training when you are not able to bear weight.
Body-weight exercises such as pushups and pullups, along with common free-weight moves like the overhead press and bent over row are staples in many effective upper body workouts. Unfortunately though, if you've recently suffered an injury, or have a bone, muscle or joint condition that prevents you from bearing weight, these exercise are out of the question. You can still train hard and get results with a non-weight-bearing upper body workout, but you'll have to get a little creative.
Pulling exercises work your back muscles, along with your biceps and traps. While standing barbell and dumbbell rows may be out of the question, you can still perform pulling movements while sitting down. If your gym has a seated row machine, use this instead. This is performed by sitting on the seat with your legs and core braced, holding the handle while keeping your back straight, then pulling your hands in to your stomach. Most seated row machines have a variety of handle attachments so you can change between these to keep things interesting. If you're training at home, use a resistance band instead, by tying it round a table leg or doorframe or looping it over your feet, then performing the same movement.
Pushing for More
To work your chest, shoulders and triceps, you need pushing movements in your routine. You can't go wrong with basic chest press, pectoral fly and seated shoulder press machines. These work the muscles hard but allow you to sit down and not bear any weight. When choosing chest machines, try to look for free-motion ones that replicate the movement of free weights as much as possible.
All About Arms
Making your arm isolation exercises into non-weight-bearing ones is surprisingly simple. If you usually perform your dumbbell curls, cable curls, triceps push-downs and overhead extensions standing up, then sit down to do them. The techniques are exactly the same, but you may need to lighten the loads slightly, as exercises are generally tougher sitting down than they are standing up. The only exercise you may have to take out completely is the barbell curl, as it's impossible to get a full range of motion on these while seated.
Guidelines and Goals
Stick to the same guidelines as you would for a regular upper body workout. Beginners should stick to three sets of eight to 12 moderately challenging repetitions on four to six exercises -- one or two pulls, one or two pushes and two arm isolations. If you're training for muscular endurance, increase your reps to 15 to 20 per set, or for strength and muscle building, increase the weight, but aim for three to five sets of six to 10. More advanced trainers may also wish to split their workouts up, with one session per week for pushing exercises, one for pulling and a third for arms.