According to Dr. Leon Popovitz, co-founder of New York Bone and Joint Specialists in New York:
“You absolutely need to stretch. I recommend stretching before, taking a break during your workout to stretch, and then stretching again after. That significantly decreases the incidences of injury while the activity is going on, and it also significantly decreases the likelihood of an injury after. This is especially important as you get older, because muscles lose their elasticity and sometimes some of their blood supply with age.” - Inspiyr.com 12/16/12
Read the rest of the article, "How to Prevent Weight Lifting Injury," on Inspiyr.com, where Dr. Popovitz lends his orthopedic expertise.