Diagnose the Tightness Before You Stretch
Never stretch a muscle until you know why it's tight
- Difficulty
- Moderate
- Time to result
- ~weeks to results
- Steps
- 3
- Confidence
- 86%
Cressey's rule is to always know why you are stretching something rather than stretching because it feels tight. Tight hamstrings, the most common complaint, are almost never genuinely shortened — because the muscle crosses two joints you rarely live in a position short enough for that. More often the tension is protective: an anteriorly tipped pelvis has the hamstrings firing to posteriorly tilt it and guard the low back, so stretching them leaves the person transiently unstable and exposed. Tightness can also come from nerve tension after a disc issue or from fibrotic tissue after a strain. The better move is often to add good stiffness or motor control elsewhere — core control, glute activation, learning to posteriorly tilt the pelvis — and the tension resolves on its own. This is why some people feel amazing after a yoga class and others feel much worse: the latter stretched out protective tension they needed.
Origin
The principle comes from Cressey's clinical experience watching people stretch reflexively and get worse, and from the postural-restoration view of tension as often protective rather than structural.
Core principles
- 01Tightness is a symptom with several possible causes, not a command to stretch
- 02Much of what feels tight is protective tension the body created for a reason
- 03Stretching protective tension can leave you transiently less stable and more exposed
- 04Adding good stiffness or motor control elsewhere often resolves the tightness without stretching
How to run it
- 1
Classify the tightness
Before stretching, determine whether the muscle is actually short, holding protective tension, or dense from nerve tension or a prior strain.
Pro tip For hamstrings, assume protective tension first — genuine shortening is rare because they cross two joints.
Watch out Stretching protective tension removes stability the body deliberately created.
- 2
Add stability where it's the real fix
For protective tension, give the system core control, glute activation, and the ability to posteriorly tilt the pelvis so the guarding tension can let go.
Pro tip Adding good stiffness in the right place will 'almost never go wrong.'
- 3
Stretch only with a rationale
Reserve stretching for cases where you know exactly which tissue needs length and why.
Pro tip Escalate to a good practitioner when you can't work out the cause yourself.
Watch out Stretching the wrong thing can make you meaningfully worse, not just fail to help.
In the wild
A person with an anteriorly tipped pelvis has hamstrings firing to posteriorly tilt it and protect the low back. Instead of stretching them, Cressey adds core control and glute activation so the pelvis is controlled and the protective tension releases.
→ The tightness resolves without stretching, and the person is not left transiently unstable.
Common mistakes
Stretching because it feels tight
Treating tightness as an automatic cue to stretch can remove protective tension and worsen instability and pain.
Ignoring the stability side
Failing to add motor control or good stiffness elsewhere leaves the underlying cause of the tension in place.
Is it for you?
Best for
Trainees and coaches dealing with chronic 'tightness' that keeps coming back.
Not ideal for
Simple, well-understood mobility limits where a targeted stretch is clearly indicated.
From the transcript
“you always want to know why you're stretching something so don't just stretch something because it's tight stretch because you have an actual rationale for…”
“if you add good stiffness to a situation you'll almost never go wrong but you can make yourself a lot worse if you stretch the…”
From the episode
#675: Eric Cressey, Cressey Sports Performance — Tactical Deep Dive on Back Pain, Movement Diagnosis, Training Principles, Developing Mobility, Building Power, Fascial Manipulation, and Rules for Athletes