By Emily Neff (Pappas), Ph.D.
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If Your Daughter Plays a High-Risk Knee Sport… This Research Should Be on Your Radar.
Soccer. Basketball. Lacrosse. Field hockey. Volleyball.
These are the sports our girls love — and the same ones that put their knees at the highest risk.
But what if there was a single strength test that could tell you whether she was protected or vulnerable?
A 2017 study published in BMJ Open Sport & Exercise Medicine found exactly that — and the results should change the way every sports parent thinks about strength training.
The Study
Researchers in Sweden followed 225 youth athletes ages 15–19 across six high-risk knee sports: soccer, basketball, hockey, handball, skiing, and floorball (Augustsson & Ageberg, 2017).
Before the athletes began their seasons, each one was tested on a 1-rep max barbell squat — a simple measure of lower-body strength relative to bodyweight.
Then researchers tracked who suffered traumatic knee injuries — including ACL tears — throughout high school.
The question was simple: does lower-body strength predict who gets hurt?
For Female Athletes, the Answer Was Clear.
Girls who tested in the weakest category had:
9.5x higher odds of suffering a traumatic knee injury.
7x higher odds of tearing their ACL.
Compared to their stronger peers.
And here’s what makes this study so important:
This relationship did NOT show up in male athletes.
The boys who were weaker did not face the same elevated risk. But for the girls, the connection between low strength and knee injury was overwhelming.
The Threshold
The researchers identified a clear line:
Girls whose 1RM squat was ≤1.05x their bodyweight had the highest likelihood of traumatic knee injury.
That means a 130-pound athlete who could squat 136 pounds or less was in the highest-risk category.
Let that sink in.
This isn’t about being elite. It’s about having a baseline of strength that her body needs to absorb force, decelerate safely, and protect her joints during the demands of sport.
Why This Hits Home for Female Athletes
During adolescence, girls gain lower-body strength more slowly than boys. That’s biological.
But here’s the problem: their sport demands don’t slow down.
Combine that with:
- Rapid growth spurts
- Sport specialization and year-round play
- Higher training volumes
- Tournament weekends with back-to-back games
And you get the perfect storm:
Less strength + More demand = Higher odds of injury.
This is why so many knee injuries happen during the ages of 14–18 — a window when physical development hasn’t caught up to the demands her schedule is placing on her body.
What We Do About It at Relentless
This study confirmed something we’ve believed since day one:
Strength isn’t optional for girls. It’s protective.
That’s why one of the most important milestones at Relentless Athletics — since we opened our doors in 2015 — is the Body Weight Front Squat Club.
Our goal for every female athlete — and especially those coming back from an ACL tear — is to front squat her bodyweight. Full depth.
Why the front squat specifically?
- Full depth for full strength — The front squat builds strength through the complete range of motion in the knees and hips, exactly where she needs it most.
- Core strength — The upright torso position demands total-body stability, training the core as a protector, not just a “six-pack.”
- Resiliency against injuries — It builds the kind of lower-body armor that keeps her on the field and off the sideline.
Full depth. Full strength. That’s the standard.
When an athlete earns her spot in the Body Weight Front Squat Club, it’s not just a number on a bar. It’s proof that her body is prepared for what her sport will throw at her.
What Parents Can Do Right Now
You don’t need to wait for an injury to act.
Here’s what the research — and our 10 years of experience training female athletes — tells us:
1. Prioritize lower-body strength training. If your daughter is playing a cutting, jumping, or pivoting sport, she needs regular, progressive strength work. Not “a few exercises after practice.” A real program.
2. Watch for spikes in training load. Extra games, tournaments, showcase weekends, and back-to-back matches create the fatigue that breaks down movement patterns — especially when she doesn’t have the strength to absorb it.
3. Start before the problem shows up. The athletes in this study who were in the weakest category didn’t know they were at risk until the injury happened. Strength testing — and strength building — should be part of every young female athlete’s development.
The Bottom Line
A 2017 study of 225 youth athletes found that weaker female athletes had nearly 10x the odds of suffering a traumatic knee injury — and 7x the odds of tearing their ACL.
That’s not a small difference. That’s a game-changer.
Strength training isn’t about making her “bulky” or turning her into a weightlifter. It’s about building the lower-body resilience that keeps her healthy, competitive, and confident for years to come.
At Relentless, that’s what we do — every rep, every session, every day.
If you want to protect your daughter’s knees and build the kind of strength that keeps her in the game, book a Discovery Call and let’s talk about a plan for her.
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References
Augustsson, S. R., & Ageberg, E. (2017). Weaker lower extremity muscle strength predicts traumatic knee injury in youth female but not male athletes. BMJ Open Sport & Exercise Medicine, 3(1), e000222. https://doi.org/10.1136/bmjsem-2017-000222
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Related Articles
- ACL Injuries: Myths, Facts, and New Research to Protect Your Daughter
- The Power of Saying No in Youth Sports
- 10 Lessons in 10 Years: What We’ve Learned Training Female Athletes at Relentless
- Strong Girls Don’t Skip Snacks
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ABOUT THE AUTHOR
Emily is the Owner & Founder of Relentless Athletics.
In 2015, Emily opened Relentless Athletics to build a community for female athletes while educating their parents and coaches on the necessity of strength training and sports nutrition to optimize sports performance and reduce injury risks in the female athlete population.
Emily holds a Ph.D. in Kinesiology with a research focus on female athletes & the relationship between Olympic Weightlifting, performance, and ACL injury rates in adolescent female athletes. She holds an M.S. in Exercise Physiology from Temple University and a B.S. in Biological Sciences from Drexel University.
Through this education, Emily values her ability to coach athletes and develop strength coaches, using a perspective grounded in biochemistry and human physiology.
When she isn’t on the coaching floor or doing work behind the scenes, she is at home with her husband, two kids, and of course, their dog Milo!
