“Stretching” isn't one single activity, and the research doesn't treat it as one. Static and dynamic stretching have different immediate effects and, separately, different roles in building flexibility over time — which is why it's not accurate to call either one universally better.
Two Different Approaches
Static stretching means holding a position without movement, typically for somewhere between 15 and 90 seconds. Dynamic stretching means actively moving a joint through its range in a controlled, repeated motion rather than holding still. Cleveland Clinic describes dynamic stretching as generally suited to a warmup, since it rehearses movement patterns and increases blood flow ahead of activity, while static stretching tends to work better as part of a cooldown, once muscles are already warm.
What Research Shows About Immediate (Acute) Effects
A 2024 systematic review with meta-analysis on the acute effects of stretching found that static stretching's overall effect on strength immediately afterward was small, but became substantially larger once a stretch was held for roughly 60 seconds or more per muscle group. The same body of research found static and dynamic stretching were both generally associated with small positive effects on subsequent jump performance — the concern with static stretching is specifically about longer holds done immediately before activity, not static stretching as a category.
Acute Effects Aren't the Same as Long-Term Effects
It's important not to confuse a stretch's effect in the minutes after you do it with its effect on flexibility built up over weeks or months. A 2025 systematic review examining the mechanisms behind range-of-motion improvements found that immediate gains after a single stretch are driven mainly by a temporary reduction in tissue stiffness, while longer-term flexibility adaptations from repeated stretching appear to be driven more by an increased tolerance to the stretch itself. In other words: a static stretch that temporarily reduces power output right after you do it is not evidence that static stretching is bad for building flexibility over time — those are different questions with different answers.
| Aspect | Dynamic Stretching | Static Stretching |
|---|---|---|
| What it looks like | Continuous, controlled movement | Holding a position, still |
| Commonly suited to | Warmups, before activity | Cooldowns, after activity |
| Acute effect on power/strength | Generally small positive effect | Minimal at short holds; more noticeable at 60+ seconds |
| Role in long-term flexibility | Less studied for this purpose | More associated with lasting flexibility gains |
Neither type of stretching is universally superior — they show different effects depending on timing (immediately before activity vs. as a separate practice) and duration, not a simple better-or-worse ranking.
Where Assisted Stretching Fits
Assisted stretching sessions typically resemble static and active-assisted technique — held positions guided by a practitioner — more than dynamic movement. That's part of why a full assisted session isn't generally meant to replace a dynamic warmup right before activity. See Assisted Stretching Before vs. After Exercise for more on timing.