Helpful warm-up advice from Brett:
When Duane Knudson, a professor of kinesiology at California State University, Chico, looks around campus at athletes warming up before practice, he sees one dangerous mistake after another. “They’re stretching, touching their toes. . . .” He sighs. “It’s discouraging.” 
While it’s great to see people doing what they can to increase flexibility and taking the initiative to prepare for a WOD, there are a few things you should know about stretching before you use the sit and split method pre-WOD.
1) Frozen meat is difficult to manipulate. Meat is muscle. And, when you take your frozen chicken out of the freezer, you cannot simply start cutting it into filets. Just like that meat, you have to warm up your muscles before you try to push into the ends of your range of motion. Get moving. Get warm. Get a light sweat going before you push your muscle to its end range.
2) A good warm up increases performance:
A well-designed warm-up starts by increasing body heat and blood flow. Warm muscles and dilated blood vessels pull oxygen from the bloodstream more efficiently and use stored muscle fuel more effectively.
3) Static stretching, the ones where you pull and hold it there for a while, leave you less prepared to do work!
“You may feel as if you’re able to stretch farther after holding a stretch for 30 seconds,” Malachy McHugh, the director of research at the Nicholas Institute of Sports Medicine and Athletic Trauma at Lenox Hill Hospital in New York City says, “so you think you’ve increased that muscle’s readiness. But typically you’ve increased only your mental tolerance for the discomfort of the stretch. The muscle is actually weaker.”
In a recent study conducted at the University of Nevada, Las Vegas, athletes generated less force from their leg muscles after static stretching than they did after not stretching at all. Other studies have found that this stretching decreases muscle strength by as much as 30 percent. Also, stretching one leg’s muscles can reduce strength in the other leg as well, probably because the central nervous system rebels against the movements.
Stretching muscles while moving, on the other hand, a technique known as dynamic stretching or dynamic warm-ups, increases power, flexibility and range of motion.
When in doubt, check this warm-up out! Watch what Greg A does here.