Posterior-Chain ACL Risk-Reduction Protocol
Balance leg strength and rehearse the movements that commonly cause injury
- Difficulty
- Moderate
- Time to result
- ~months to results
- Steps
- 5
- Confidence
- 94%
Dr. Stacy Sims presents ACL risk reduction as a combination of balancing muscular forces and preparing athletes for the actions that commonly produce injury. She says women tend to be more quadriceps-dominant, so training should deliberately develop the posterior chain: glutes, hamstrings, and calves. That strength work is paired with landing, jumping, single-leg, lateral, and cutting practice so the athlete can distribute force more evenly and control twisting movements. The protocol is especially relevant to grassroots settings, where she says these movement patterns are often missing from warm-ups. This is a risk-reduction framework, not a guarantee against injury, and anyone with pain or a previous tear needs individualized clinical guidance.
Origin
Extracted from The Diary of a CEO
Core principles
- 01Treat strength imbalance and movement mechanics as trainable risk factors
- 02Balance front-of-leg strength with the posterior chain
- 03Practise the lateral, landing, and single-leg actions the sport demands
- 04Use sport-specific preparation rather than a generic warm-up
How to run it
- 1
Identify the imbalance
Assess whether the quadriceps dominate the hamstrings and posterior chain. Use a qualified coach or clinician when formal testing is needed.
Pro tip Treat side-to-side differences and movement quality as useful context, not just raw strength numbers.
Watch out Do not self-diagnose an injury from a strength imbalance alone.
- 2
Build the posterior chain
Train the glutes, hamstrings, and calves so the back of the leg can better balance the pull from the quadriceps.
Pro tip Progress load gradually while preserving control through the full movement.
Watch out Pain, swelling, or instability warrants professional assessment.
- 3
Rehearse landing and jumping
Practise jumping, landing, and single-leg jumping with deliberate alignment and control.
Pro tip Start slowly before adding speed, height, or fatigue.
Watch out Do not add explosive volume faster than the athlete can recover from it.
- 4
Train lateral power
Add side-to-side movement, stopping, pivoting, and cutting drills that resemble the demands of the sport.
Pro tip Coach the deceleration and stop, not only the push-off.
Watch out Generic straight-line conditioning does not prepare every direction of force.
- 5
Make prevention routine
Place the strength and movement drills inside the regular warm-up so they are repeated consistently.
Pro tip Select drills that match the athlete's sport and level.
In the wild
A recreational football team replaces part of its straight-line warm-up with progressive hamstring and glute work, controlled single-leg landings, lateral bounds, and coached cutting drills. The coach keeps the movements slow until players can stop and land with control, then gradually adds speed.
→ The team consistently rehearses the strength and mechanics Sims identifies as relevant to reducing ACL risk.
Common mistakes
Training only the quadriceps
More front-of-leg strength can preserve the imbalance the protocol is meant to address. Develop the posterior chain deliberately.
Skipping lateral movement
Straight-line work alone does not rehearse the cutting and twisting actions discussed in the episode.
Treating prevention as a guarantee
The framework targets modifiable factors but cannot eliminate injury risk.
Is it for you?
Best for
It is best for women who play sports involving jumping, landing, pivoting, or rapid lateral movement.
Not ideal for
It is not a substitute for assessment, rehabilitation, or clearance from a qualified clinician after an injury.
From the transcript
“It comes down to the definitive difference between quad and hamstring strength.”
“We have to work a lot of the explosive lateral movements”
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