+Jake Fapper warm up before lifting is to warm up the muscles & connective tissue, so gentle dynamic (moving, short) stretches only. To lengthen your muscles/improve mobility do the static (should be at least 30 secs) stretching at a different time (anytime) as your body needs time to adjust to the stretch. It's a bit like a rubber band, if you do lots of long hard static stretches before exercise you are more likely to injure yourself as everything is "loose" & responding to the stretch rather than warmed up enough to handle the lifts (if that makes sense)