3x10 = 0 with Ankle Support

3x10 = 0 with Ankle Support

Last month we wrote about the importance of regaining knee extension range of motion. The ability to fully straighten your knee both following and before surgery is essential. Without that full extension, your knee works differently and is at risk for premature wear. 

We have long used--for nearly 20 years--the 3x10=0 device to help patients regain this motion. 

Why does it work?

There are two primary reasons for the success of the 3x10=0:

  • It relies on a biomechanical concept called creep
  • It makes the stretch much more effective.


Creep is "the progressive deformation of a structure under constant load when the materials are stressed well below their fracture thresholds" 

Tendons (and other structures in your knee) have viscoelastic properties which means their behavior depends on the rate of mechanical strain. In other words, strain on structures depends on the time that structure is experiencing that strain. While these structures do respond to high strains, they prefer low strains when the goal is changing their length.

To increase extension range of motion, we therefore need low strains or loads. In addition, this strain must be under constant load. The structures that prevent full extension are not elastic; as such, they respond best to constant--non-cyclic--loads or strains.

Ankle Support

So why use the ankle support? Aren't there other, less expensive models that are just as good?

We prefer the ankle support for one primary reason. In nearly every patient we have ever worked with, there is a tendency for the leg to roll outward so the foot and toes point to the side and not straight up and down. When this outward rotation occurs, the force is no longer trying to straighten the knee making the exercise ineffective. The ankle support provided in this model encourages the leg to not rotate so the foot and toes point up. This allows nearly all the strain talked about above to help the knee get straighter. This really is a game changer and we see it as essential to optimize the exercise.

In our experience, the 3x10=0 device with ankle support meets all the goals required of someone needing to increase knee extension range of motion.


Alessa F, Ning X. Changes of lumbar posture and tissue loading during static trunk bending. Hum Mov Sci. 2018;57:59-68. doi:10.1016/j.humov.2017.11.006

Bolcos PO, Mononen ME, Mohammadi A, et al. Comparison between kinetic and kinetic-kinematic driven knee joint finite element models. Sci Rep. 2018;8(1):17351. Published 2018 Nov 26. doi:10.1038/s41598-018-35628-5

Korhonen, Rami & Saarakkala, Simo. (2011). Biomechanics and Modeling of Skeletal Soft Tissues. 10.5772/19975. 

Toosizadeh N, Nussbaum MA, Bazrgari B, Madigan ML. Load-relaxation properties of the human trunk in response to prolonged flexion: measuring and modeling the effect of flexion angle. PLoS One. 2012;7(11):e48625. doi:10.1371/journal.pone.0048625

Twomey L, Taylor J. Flexion creep deformation and hysteresis in the lumbar vertebral column. Spine (Phila Pa 1976). 1982;7(2):116-122. doi:10.1097/00007632-198203000-00005

Uzuner S, Kuntze G, Li LP, Ronsky JL, Kucuk S. Creep behavior of human knee joint determined with high-speed biplanar video-radiography and finite element simulation. J Mech Behav Biomed Mater. 2022;125:104905. doi:10.1016/j.jmbbm.2021.104905

Vaquero-Cristóbal R, Molina-Castillo P, López-Miñarro PA, Albaladejo-Saura M, Esparza-Ros F. Hamstring extensibility differences among elite adolescent and young dancers of different dance styles and non-dancers. PeerJ. 2020;8:e9237. Published 2020 May 26. doi:10.7717/peerj.9237

Back to blog