Increase muscle strength with barbell exercises done while lying down. Learn about muscle training, fitness, and growth in this fitness video. Take action: do not rock arms and keep core tight. Michelle, the instructor in this how-to video, is a personal trainer at a gym in NC and has been a personal trainer for several years. She is certified through ACE and is a certified aerobics instructor as well. Her Specialty is weight lifting and she enjoys training aspiring female body builders as she is one herself. She focuses on helping her clients stronger, healthier, and sending them out feeling better for it. The best part of her job is when she see people living a better life as a result of the physical training. She was also a Marine physical trainer before she was employed at the gym. Watch this video weight-lifting tutorial and learn how to do skull crusher lying barbell extensions.