During holiday I workout in gym for almost 3~4 months. From 56kg I gain up to 67kg in 2~3 months. I gain muscle and I am happy with my improvement. The problem is when I begin training lately. My reaction is too slow because my body is heavier than before. How I can increase my speed and should I change 'mass program' that I use now to something else. I still want to increase my muscle size.