As a female athlete, you are far more likely to suffer a non-contact ACL tear than your male counterparts. And one main cause of ACL injuries in female athletes is “knock knees,” a condition where the knees curve inward and touch but the ankles are far apart.
For female athletes, knock knees (technically called “valgus knee”) can occur when you squat or land from a jump and your knees collapse inward. The angle of your hips plays a large role in this problem. Women tend to have wider hips and a more pronounced angle from hips to knees than men. However, tight inner thighs (adductors) and underactive or weak outer hips (abductors) as well as hip extenders (glutes) can increase the opportunity for knock knees.
To help prevent knock knees and ACL injuries from occurring, you should stretch your hip adductors and strengthen your glutes. This combination is crucial in correcting knee/hip alignment. When the hip adductors are tight, they pull the thighs (femurs) in, creating the curvature that we see with knock knees. By stretching and lengthening your adductors—while also strengthening your glutes—you can help fix knock knees and prevent injury.
Below are some exercises to add to your training program that target the hips, thighs and knees:
Mini Band Squat
This is a great move to practice keeping your knees over your feet. The band will try to pull your knees toward each other; push out against the band to prevent this.

• Position band just above knees
• Position feet shoulder-width apart, pointing straight ahead with a slight outward angle
• Push hips back and squat while keeping head and chest up
• Keep knees over feet and push out against band

Sets/Reps: 3×15

Step-Up
The Step-Up is a great exercise for single-leg strength, and the gluteus medius helps stabilize the hips during individual leg movements. Hold dumbbells in each hand to increase the difficulty of the exercise.

• Start with one foot on plyo box or bench and other foot six inches away from box
• Drive off with foot on top of box; land on box
• Slowly return to start position while leaving same foot on box
• Repeat for specified reps; perform on other leg

Sets/Reps: 2-3×12 each leg

Physioball Leg Curl
Another great movement, because you get the benefits of a Hamstring Curl while also getting some hip extension. This exercise targets the hamstrings and glutes. Once you’ve mastered it, try performing it one leg at a time for increased difficulty.

• Place feet on top of physioball, just past center
• Pull ball toward body while simultaneously raising hips off ground
• At top of movement, maintain straight line from knees to shoulders
• Return ball in a controlled manner to start position

Sets/Reps: 2-3×12

Physioball Hip Extension
This exercise targets the glutes. Perform it one leg at a time for increased difficulty or as a superset after the Physioball Leg Curl.

• Place heels on ball, creating a slightly less than 90-degree angle bend with knees
• Driving off heels, raise hips off ground until you have straight line from knees to shoulders
• Hold at top for two seconds; slowly return to start position

Sets/Reps: 2-3×12

Lateral Band Walk
The Lateral Band Walk targets the hip abductors (gluteus medius). While performing the exercise, do not drag your feet or let them get too close together. The band should always have tension throughout the exercise.

• Position mini band just above ankles
• In athletic position, take large, controlled steps to side

Sets/Reps: 2×15 in each direction

Standing Hip Adductor Stretch
This stretch targets your inner thighs, which, as mentioned earlier, are often a problem area for female athletes with knock knees. Perform this exercise at the end of all your training sessions.

• Take big lateral step with left leg
• Sit hips down and back toward left leg
• Place feet flat on the ground and point them straight ahead
• Stretched leg remains straight

Sets/Reps: 1-2×30-60 seconds each leg

For more information on the ACL please see the STACK ACL Guide.
Bill Delongis, CSCS, is the head strength and conditioning coach at Converse College (Spartanburg, S.C.), where he oversees speed, strength and conditioning programs for all eight sports. He is a graduate of Winthrop University, where he  studied fitness and wellness with a minor in coaching. He is also a NASM corrective exercise specialist, USAW sports performance coach and a certified personal trainer.