Never do static stretching before a workout. Ride a stationary bike, do moving stretches etc. You need to warm up your body before working out, not stretch.
I'm curious too. I have one of my best friends his father is a trainer on his own with athletes and he always tells us we do everything wrong for our school team. We do these regular old fashioned streches where you hold for 10 seconds and my friends dad said you should never hold your stretch when you're trying to warm up that we should do movement warm up. It had a specific name to it but i forget.
Never do static stretching before a workout. Ride a stationary bike, do moving stretches etc. You need to warm up your body before working out, not stretch.