If you want to build bulk and strength with weight lifting, don’t just stick to slow, heavy lifts.   Now research shows that FAST explosive movements such as kettlebell swings, box jumps and plyometric push-ups will give you a greater response from your “fast twitch” muscles fibers -- the ones used during quick, strong movements. These fast-twitch muscle fibers have greater potential for growth compared to slow-twitch fibers.  So be sure to add speed to your workout routine.