For decades, the ritual of stretching before exercise has been a cornerstone of fitness culture, widely believed to be a sure-fire way to ward off injuries. But is this common wisdom actually true? According to a leading sports scientist, the answer is more nuanced than a simple yes or no, and the type of stretching you choose is critically important.
The Biomechanics of Injury: More Than Just Tight Muscles
Dr Alex Dinsdale, a senior lecturer in sport and exercise biomechanics at Leeds Beckett University, clarifies that injuries occur for a multitude of reasons. These can range from unsuitable footwear and general fatigue to two primary biomechanical factors: an insufficient range of motion or a lack of strength to control that motion.
"You might go for a run and lift your knees higher than your hamstrings can manage," Dinsdale illustrates. Alternatively, you may simply not possess the necessary muscle strength to handle a limb moving at high speed. This insight shifts the focus from merely 'loosening up' to ensuring your body is adequately prepared for the specific demands of your activity.
Static vs. Dynamic: The Crucial Stretching Divide
When most people think of stretching, they imagine static stretching – holding a muscle under tension in a fixed position for six seconds or more. This method, explains Dinsdale, has a mixed effect. While static stretching can increase your range of motion, it also temporarily decreases the force a muscle can produce by approximately 5%. This potential reduction in power could be detrimental right before a workout or competition.
The alternative, dynamic stretching, involves moving through a stretch with controlled motion. Exercises like bodyweight squats, walking lunges, or leg swings fall into this category. "It doesn't increase range of motion as much," Dinsdale notes, "but it can increase the muscle's capacity to produce force." This makes dynamic stretching a more balanced and functional choice for a pre-exercise routine.
The Ideal Pre-Exercise Protocol
So, what should you actually do before a workout? For the majority of exercisers, Dr Dinsdale recommends a three-phase approach. First, begin with a general warm-up involving light movements that mimic your upcoming activity, such as a brisk walk before a jog. "Increasing the temperature of your muscles helps them produce force more effectively, and you gain a bit more range, too," he says.
Following this, incorporate a few dynamic stretches that guide your joints and muscles through the specific motions you're about to perform. To complete the priming process, he suggests finishing with some powerful, explosive movements like a few jumps or a short, sharp sprint. This final step activates the neuromuscular system, preparing your body for action.
Perhaps most importantly, Dinsdale highlights that what you do separately from your main exercise is key. He advocates for "assistance training" – dedicated sessions for strength training and static stretching held at a different time. This builds the foundational strength and flexibility in the muscles you rely on, addressing the root causes of injury risk far more effectively than any last-minute stretch.
