Biomechanical Changes During a 90º Cut in Collegiate Female Soccer Players With Participation in the 11.
Celeste Dix, Amelia Arundale, Holly Silvers-Granelli and 3 others
PMID 34123519WHAT IT FOUND
Soccer players using the 11+ warm-up showed a clinically meaningful reduction in risky knee collapse during a 90° cut on their non-dominant leg.
This change did not reach statistical significance, so treat it as a promising signal rather than proof of efficacy.
Key findings
01The intervention group demonstrated a clinically meaningful decrease in knee valgus collapse on the non-dominant limb, though this change did not reach statistical significance.
02Reductions in hip internal rotation angles were observed but occurred in both the intervention and control groups, so they cannot be attributed to the 11+ program.
03The intervention group showed a statistically significant decrease in non-dominant hip adduction angle, suggesting hip mechanics may drive changes in knee alignment during cutting.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
The study was not randomized; teams self-selected into intervention or control groups based on willingness. Individual player adherence to the 11+ was not tracked, so it is unclear if biomechanical changes correlate with how often players actually performed the exercises. The cutting task was anticipated, whereas many real-world ACL injuries occur during unexpected maneuvers. Participants were collegiate athletes (mean age 19.1 years), so results may not apply to younger athletes who typically show greater neuromuscular adaptation.
Declared interests
All authors declare no conflicts of interest.
The easy way to misread this
Do not assume the 11+ significantly alters knee abduction moments. The study found no significant change in this metric, and the reduction in knee valgus collapse was only clinically meaningful, not statistically significant. Treat the biomechanical improvements as suggestive evidence rather than definitive proof of altered movement patterns.