Instead of stretching before your workout, perform a warm-up routine instead. Studies show that simply increasing muscle temperature can improve exercise performance in several ways, one of which being the rate of ATP (energy) supply. Utilize a dynamic warmup – running, plyometrics, or high reps and low weights working muscle groups that you plan on hitting that day. 5-10 minutes and a light sweat are what you need to get started!
Reference: Bishop, D. (2003). Warm up I. Sports Medicine, 33(6), 439-454.