Stretching science: what UK guidance actually says
Stretching advice has changed significantly in recent years. The British Journal of Sports Medicine 2023 guidelines moved away from the once-standard "hold for 30 seconds" rule. Current evidence supports 10-30 second holds for most adults, with 20-30 seconds being the sweet spot for flexibility gains without reducing muscle performance. Sport England and the NHS recommend incorporating stretching into post-exercise cool-downs at least 2-3 days per week.
The key finding that changed practice: prolonged static stretching (over 60 seconds per muscle) before explosive sport reduces power output. The UK sports medicine community now distinguishes clearly between dynamic stretching (warm-up) and static stretching (cool-down).
Stretching protocols by goal
| Goal | Type | Hold | Reps | Timing |
|---|---|---|---|---|
| Flexibility gain | Static | 20-30 s | 3-4 | After exercise |
| Pre-run warm-up | Dynamic | N/A (movement) | 10-15 per side | Before exercise |
| Injury prevention | Static | 20-30 s | 2-3 | After exercise |
| General maintenance | Static | 15-20 s | 2 | Any time after warm-up |
Types of stretching
Static , hold a position without movement. Best after training. This is what this timer supports.
Dynamic , controlled movement through a range (leg swings, arm circles). Better before training; warms the tissues without reducing power.
PNF (proprioceptive neuromuscular facilitation) , contract-relax technique used by physiotherapists. The UK Sports Massage Association recommends this for rapid flexibility gains but it typically requires a partner or therapist.
Limits of this timer
This timer guides the duration of holds and rest periods. It does not prescribe specific stretches or assess injury risk. Consult a qualified healthcare professional before starting a stretching programme if you have joint pain, hypermobility, or are recovering from injury.
For pre-training cardio intervals, use the Interval Timer.