Single leg stability is a staple in human performance.
The ability to control the body proximally and distally through one leg translates into our daily function with walking, stairs, running and changing direction.
It is magnified with our participation in sports and athletics. Deficient single leg control especially eccentrically (length of the muscle increases as tension is produced) is correlated with a higher rate of injury.
- Combining poor neuromuscular control with other factors such as fatigue, which occurs during competition, poses an increased risk for injury.
- Velocity and speed combined with poor neuromuscular control are also key factors that increase the chance of injury.
During intense training and competition, moving fast and dynamically at a hard effort is expected. These efforts combined with other stressful factors such as fatigue, weather conditions, terrain conditions and interaction with other individuals in contact sports post a risk for orthopedic injuries, especially to the knee.
A Word About ACL Injuries
ACL (Anterior Cruciate Ligament) injuries have been steadily increasing in youth athletes, especially in females for soccer and males for football, measuring up to 400 tears per 100,000 person-years in adolescents.
ACLs are one of the leading orthopedic knee injuries and occur in field sports and team based sports more than endurance sports, mostly due to the mechanism of injury.
The plant and twisting, cutting, decelerating and change of direction mechanics required in field sports can expose athletes to these types of injuries more than runners, cyclists, rowers or swimmers.
The same failure in appropriate mechanics and muscle control that can lead to an ACL tear can also contribute to other issues such as meniscus injury, patella tendinopathy, patella femoral syndrome and IT band syndrome.
The faulty mechanics that predispose the knee towards injury are valgus, internal rotation of the femur and corkscrewing.
What Is Knee Valgus?
Valgus is when the knee moves inwards (think knock knee posture) resulting in the medial side of the knee moving past the foot and ankle.
- Internal rotation is when the femur rotates causing the thigh to turn inwards.
- Corkscrewing is when the pelvis rotates and twists away to help maintain counter balance against the rotating femur.
If muscle function is sufficient to execute single leg movements with good quality, it is important to assess the function upon addition of load and resistance, fatigue and on unstable surfaces.
Training movements under these parameters will help to translate to the demands of sport and competition.
When the term “single leg squat” is heard, most think of a pistol squat but actually a single leg reverse dead lift (RDL) or hip hinge pattern correlates more to the positions required for running and in sports.
It also is the position where most injuries occur. In field sports and in running, it is very rare to assume a pistol squat position, especially repetitively.
Techniques used to help correct the single leg squat pattern
The spiral technique is a great method frequently taught by Dr. Trent Nessler PT, DPT.
It requires use of band wrapped in a pattern to help create the valgus/internal rotation forces, which then cues the person to become more sensitive to the forces acting on their knee so they can learn how to correct them.
The feedback from the band pulling will provide a tactile stimulus to sequence the proper muscles to maintain stability.
A CLX band is best used for this technique:
Technique for wrapping the band
Start by looping one end of the band around one leg at the upper thigh with the continuing part of the band at the inside of the thigh.
- The band is then looped around the back of the thigh, coming around the outside of the leg, across the top of the knee and then back around the outside of the leg and across below the knee.
- Put the opposite foot into one of the loops.
- Resistance can be adjusted by choosing a loop either closer to the lower leg of farther away.
- The extra band can be tucked into the loop around the foot.
CLX Band Reverse Slider with Assistance
This technique is used to help learn sensitivity to the band and understand how to control the front leg while extending the opposite leg.
- A dowel is used to balance assistance and the slider is used to guide the lower leg into extension.
- Focus on preventing the front knee from collapsing inward against the pull of the band.
- Also focus on preventing the low back from excessively extending and your torso from rotating.
This is an example of valgus and internal rotation movements. This is what you want to avoid and are working to correct.
- The knee and femur rotate and move inwards over the ankle and midline.
- The medial arch of the foot collapses into pronation.
- The torso rotates away as the rear foot moves behind the stance leg.
In this example, to the right since the stance leg is the right leg. This is to counter balance the rotating occurring at the front leg. The rear leg should move directly backwards.
CLX Reverse Slider Assisted with slider only
This technique is the same as previous but now you get rid of the dowel. This will require more control in the torso. The focus point again is to move the rear leg behind you while controlling the front stance leg against the pull of the band.
CLX Single Leg Squat with Dowel
This technique forces you to focus on more control now that the rear leg is off of the ground.
- The dowel helps for balance while you push the rear leg behind you while controlling the front stance leg.
- Also focus on avoiding lumbar extension and keep the torso neutral with a slight bend forward.
- The bending is coming from hip flexion not spinal flexion.
CLX Single Leg Squat Regular
Once you can demonstrate good control with the dowel assistance, progress to getting rid of the dowel and work on executing the single leg squat against the band without any extra support.
CLX Single Leg Squat with Core Band
A final challenge is to grab the extra band at the rear foot and hold it at the mid torso height.
- While executing the single leg squat, push the band straight out and up while keeping the line of the driving force in parallel with your spine.
- While the rear foot extends behind you, your arms should be extending out at the same time.
The CLX band works great for this technique as well as other forms of exercise where focus on spinal control with multiple points of resistance are required. For this technique a regular resistance band with a loop on each end can work but may not be as efficient as the CLX band.
Practicing these drills can help restore a proper foundation before progressing to more aggressive styles involving weights and plyometric movements.
Ensuring a strong foundation is a good way to prevent injuries from creeping up, especially between training blocks, changes in training styles and during off season times.
It is also is good for the non athletic population to practice to ensure a solid foundation in single leg control to prevent knee issues with everyday life and demands.
About The Author:
Michael St. George PT, DPT has been practicing for 10 years primarily in the outpatient and orthopedic setting. He works for a physical therapist owned private practice based in the greater Philadelphia area and surrounding suburbs. Mike is certified through Functional Movement Systems for FMS, SFMA and FCS which consist of screens and testing used to measure movement quality and performance. Mike also has experience with working with numerous surgeons and physicians from the Rothman institute. Currently he works primarily with ACL, meniscus and post surgical recovery and sports injuries, return to sport testing and performance, running evaluation and re training and hand and upper extremity conditions
- Bram, j., Magee, L., Mehta, N. Anterior Cruciate Ligament Injury Incidence in Adolescent Athletes: A Systematic Review and Meta- analysis. The American Journal of Sports Medicine. 2021; 49(7) : 1962-1972