Guy didn’t know what he could do. His clothing was feeling smaller on him by the second. his arms felt more constricted in their swaying movement as the cloth on his back stretched taut. His legs were pushing apart with increasing amounts of muscle, his shorts were now riding around his thickening quads and his boxers now exposed by the long tears on the back of the shorts.
He moved slowly and carefully to a corner in the gym's locker room, hoping no one would come in and see him, now outgrowing all his formally loose gym-wear. When was this going to stop? Thoughts raced through his head nervously. He bent his arms experimentally, flexing his arms, which had become massive bowling ball-sized mounds of solid muscle. His whole body was feeling meatier, his lats pushing against his arms, his legs pushing against themselves, his traps pushing against his widening neck and shoulders... He could not move a joint without out rubbing against muscle.
He was still growing, but now a little ways of the scale he didn’t know how much he had grown... or what was going to happen. It did feel like the energy running through him was slowing down a little, but was that just fatigue or his growth stopping? Looking down he just saw a his chest, and strained fabric, which was now tearing all along his arm pits....