Colleagues, I am interested in studying ankle movements in conjunction with
knee motion. Measures of movement accuracy or detection of movement are
typically performed at either the knee or ankle in isolation from one

I am looking for a system that can control both knee and ankle displacement
and movement velocity. I do have access to a Biodex System 3 and am
considering using this to control the knee. In this case I need to
interface an ankle system with the existing Biodex System 3.

Can anyone recommend a system (i.e. servomotors, linear actuators,
mechanical linkage...) that either...
1. Simultaneously Control ankle and knee position and movement
velocity or...
2. A light-weight apparatus that can easily be attached to an
existing Biodex apparatus?

In either case this device should independently control both
position/velocity while providing accurate measures. In addition, noise and
vibration created by this device should be negligible, minimizing unwanted
feedback to subjects being tested.

Below are some references that have used some commercial units or a custom
device to measure single joint movements.

I appreciate all comments regarding the instrumentation as well as the
approach stated above. All comments will be posted.

1. Aydin, T., Yildiz, Y., Yildiz, C., Atesalp, S. and Kalyon, T.A. (2002)
Proprioception of the ankle: a comparison between female teenaged gymnasts
and controls. Foot Ankle Int. 23: 123-9.
2. Barrack, R.L., Skinner, H.B., Brunet, M.E. and Cook, S.D. (1983) Joint
laxity and proprioception in the knee. Physician and Sportsmedicine.
3. Konradson, L., Raven, J.B., Sorensen, A.I., (1993) Proprioception at the
ankle: the effect of anesthesia. J Bone Joint Surg Br. 75:433-436.
4. Lephart, S.M., Kocher, M., Fu, F.H. (1992) Proprioception following ACL
reconstruction. J Sport Rehab. 1: 188-190.
5. Refshauge, K.M., Kilbreath, S.L., Raymond, J. (2000). The effect of
recurrent ankle inversion sprain and taping on proprioception at the ankle.
Med Sci Sports Exerc. 32:10-15.
6. Weiler, H.T. and Awiszus, F. (2000) Differences between motion-direction
perception and unspecific motion perception in the human knee joint. Exp
Brain Res 132, 523-30.

Thanks in advance.

Timothy J. Brindle PhD, PT, ATC
Postdoctoral Research Physical Therapist
Physical Disabilities Branch
Building 10 Room 6s235
10 Center Drive MCS 1604
National Institutes of Health
Bethesda, MD 20892-1604
Phone: 301.451.4927
Voicemail: 301.443-8000x10501
Fax: 301.480.9896

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