It depends on what kind of stretching you do and how long you hold it. Dynamic stretching, where you move through a range of motion without holding a position, is generally helpful before a workout. Static stretching, where you hold a muscle in a lengthened position for an extended time, can actually reduce your strength and power if you do too much of it. The distinction matters more than most people realize.
Static Stretching Can Cost You Performance
Holding a stretch for more than 60 seconds per muscle group before exercise leads to a measurable decline in strength and power, somewhere between 4% and 7.5%. That might not sound dramatic, but if you’re about to squat heavy, sprint, or play a competitive sport, you’re starting at a disadvantage. One large review of 106 studies found an average performance drop of 7.5% in muscle strength after 60-plus seconds of static stretching per muscle.
Shorter holds are less problematic. Brief static stretches of 30 seconds or less, especially when folded into a broader warm-up that includes movement, don’t appear to cause the same impairment. A recent international expert consensus confirmed this: short-duration static stretching combined with a dynamic warm-up does not meaningfully hurt strength, speed, or explosiveness. The issue is isolated, prolonged static stretching right before intense effort.
Dynamic Stretching Primes Your Body
Dynamic stretching, think leg swings, walking lunges, arm circles, high knees, works with your body’s warm-up process rather than against it. It raises your core and muscle temperature, increases heart rate and blood flow to working muscles, and helps oxygen unload from your blood into your tissues more efficiently. These are the same things that happen during any good warm-up, but dynamic stretching adds the benefit of moving your joints through sport-relevant ranges of motion at the same time.
The performance benefits are modest but real. Studies show dynamic stretching can increase vertical jump height by roughly 2% to 5%, and when compared head-to-head with static stretching, the difference becomes clear: one study found a 1.8% improvement in jump performance with dynamic stretching versus a 1.6% decline with static stretching. That gap widens in activities requiring explosiveness, agility, and quick direction changes.
Stretching Doesn’t Prevent Injuries the Way You Think
One of the most persistent reasons people stretch before exercise is to avoid getting hurt. The evidence doesn’t support this. A pooled analysis of over 2,600 military trainees, split between stretching and non-stretching groups, found only a 5% reduction in injury risk from pre-exercise stretching, and that result wasn’t statistically significant. In practical terms, the stretching protocols used made no meaningful difference in whether people got injured.
An international panel of stretching researchers recently reviewed the full body of evidence and concluded they do not recommend stretching for injury prevention in general. There’s some early evidence that static stretching might slightly reduce muscle-specific injuries, but the effect is small enough that athletes and coaches need to weigh whether the time investment is worth it. A proper warm-up that gradually increases intensity does far more to protect you than touching your toes for 30 seconds.
What a Good Pre-Workout Warm-Up Looks Like
The most effective approach is a dynamic warm-up lasting 7 to 10 minutes, performed right before your workout. Start with light cardiovascular activity like jogging, jumping jacks, or cycling to get your heart rate up. Then progress into dynamic stretches that target the muscles you’re about to use: leg swings for a lower-body session, arm circles and band pull-aparts for upper-body work. Gradually increase the intensity of your movements so your body isn’t shocked by the first working set.
If you want to include static stretching because a particular muscle feels tight or you need more range of motion for your activity, keep each stretch under 30 seconds per muscle and follow it with dynamic movement. This approach gives you the flexibility benefit without the performance cost. The expert consensus is clear: stretching during a warm-up is a viable option to temporarily increase range of motion, but it’s not essential. What is essential is raising your body temperature and preparing your cardiovascular system for effort.
How It Differs for Runners and Lifters
For recreational runners, both static and dynamic stretching before a run appear to improve running economy and reduce how hard the effort feels. One study had runners perform either 30-second static holds or 30-second dynamic movements targeting the quads, hamstrings, hip flexors, adductors, and glutes. Both groups ran more efficiently at submaximal speeds and reported lower perceived effort during a run-to-exhaustion test. For steady-state endurance work, the type of stretching matters less than simply doing some kind of movement preparation.
For strength and power athletes, the calculus is different. When your goal is to move maximum weight or generate peak force, prolonged static stretching before lifting is a bad idea. Stick with dynamic stretches and warm-up sets that progressively load the movement pattern you’re about to perform. If you need to stretch a tight hip or ankle to hit proper depth in a squat, a brief static stretch followed by bodyweight squats is a reasonable compromise. Just don’t sit in a deep hamstring stretch for two minutes and then walk over to the deadlift platform.