The best exercises for the back when done correctly are the deadlift, pullups and rows either barbell or dumbell. The dumbells will allow a greater range of motion than a barbell. As for the deadlift it develops the whole back and works the hams and glutes as well. If you cant do pullups then you can do pulldowns to the chest to get the same effect. Lastly there are different hand positions doing the rows to stress different muscle groups in the back. Stay Tuned for more later.