MORE: 10 Exercises That Are A Total Waste Of Your Time To get the most out of your run, you need to be efficient. Imagine how far you could get—or how fast—if you waved your arms over your head while pounding the pavement. In the new study, published in Strength & Conditioning Journal, the authors found that the wrong kind of stretches can undermine one measure of your efficiency—or “running economy:” How well your muscles use oxygen during a jog. After reviewing more than 50 studies on flexibility and running economy, the researchers discovered that certain moves actually make you a less efficient runner. Here are 3 fundamental stretching mistakes you might be making: You perform “static” stretches before runningUltimate Flat Belly DVD Bend at the waist, come as close to touching your toes as possible, and hold the position for 30 seconds. That’s a static stretch, and it can hamper your performance, the study authors say. In many ways, your muscle tendons are like rubber bands. The shorter and less flexible they are, the faster they snap back. In distance running, tighter hamstring tendons that snap back with less effort required on your part, allowing you to conserve oxygen and energy. Static stretching lengthens those muscles and leads to an inefficient stride, the authors say. (Working hard to lose weight? Get more ideas for your workout with the .) You skip “dynamic” warm-up movements Dynamic moves such as lunges, high-knee walking, and hip lifts are excellent for preparing your body to run, the study finds. These full-body movements “activate” your muscles without harming running economy the way static stretching does because they warm up without being overstretched, the authors say. Here are some more great dynamic warm-up movements. MORE: 4 Moves To Tone Your Arms—Fast You lack hip and knee flexibility Stiff hamstrings may help your running economy, but tight hips and limited knee flexibility can equal less efficiency for distance runners. When your hips are tight, they can throw off your alignment and impede your ability to get a good push-off during your running stride, the researchers say. Inflexible knees will add resistance to every step, and your running economy will suffer. The researchers recommend stretches that target the rectus femoris—a muscle that runs from your knee, along the top of your thigh, and ends up at your hip. Try something like the rear-foot-elevated quad stretch—just don’t perform it within 30 minutes of a run. Try doing the move at least 3 times a week.