The research: PNF uses a contract-and-hold method that usually involves a partner, which makes it inconvenient for lone workouts. So researchers from William Peterson University in Wayne, New Jersey, developed and tested a self-administered version of the stretch to compare it to static stretches. Study participants were put into one of two groups, static or self-PNF hamstring stretches for the six-week study. For both the static stretches and the self-PNF testing, volunteers placed one foot on a chair approximately 20 inches in height, while keeping the other foot on the floor. The static stretch group simply held a stretch for the entire 40 seconds. The self-PNF group performed a static stretch for 15 seconds followed by a 10-second hamstring isometric contraction where they contracted their hamstrings by pushing into the chair to 90% of maximum effort. They then followed with another 15-second static stretch. (See the video below for a quick demonstration.) Researchers Jason Wicke, PhD, and Michael A. Figeuroa, Ed.D, CSCS, found a significant difference in range of motion of the hip after the PNF stretching compared to the static stretch. “It’s a superior stretching technique to static stretching,” says Dr. Wicke. PNF stretching helps prevent knots and realigns muscle fibers and connective tissue associated with microscopic damage triggered by a vigorous workout. Use it: For these reasons, Dr. Wicke recommends PNF stretching only after a workout. “PNF stretching (as well as static) reduces power output if done before a workout,” he says. Focus on only two muscle groups a day, since performing each stretch twice per muscle for the full 40 seconds takes time. “Stretching muscles properly three times a week is more beneficial than stretching more often but for only 10 seconds,” says Dr. Wicke. More from Prevention: Increase Your Flexibility 205%
