We sit in uncomfortable positions for long periods of time and end up with back pain. "A 20-year-old has the same level of... moreWe sit in uncomfortable positions for long periods of time and end up with back pain. "A 20-year-old has the same level of spinal health as a 30- or 40-year-old," says Dr. Kang. The age of mobile phones and online work is hunchbacked this generation.