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Scott Delp

This data set provides the parameters needed to develop a computer model of the human lower limb. It is based on a model developed at the VA Rehabilitation R&D Center in Palo Alto California from 1987-1990. All data may be used and copied for non-commercial use. The data set includes descriptions of bone surfaces, joint kinematics, muscle lines of action, and muscle force-generating parameters. This data allows one to calculate the lengths, moment arms, forces, and joint moments generated by forty three muscles of the lower limb. The data set is presented in several files.

PARAMETERS FOR A MODEL OF THE LOWER LIMB

Scott L. Delp, Ph.D.
Departments of Biomedical Engineering and Physical Medicine and Rehabilitation, Northwestern University, Sensory Motor Performance Program, Rehabilitation Institute of Chicago.

BACKGROUND

This data set provides that parameters needed to develop a computer model of the human lower limb. It is based on a model developed at the VA Rehabilitation R&D Center in Palo Alto California from 1987-1990. All data may be used and copied for non-commercial use. The data set includes descriptions of bone surfaces, joint kinematics, muscle lines of action, and muscle force-generating parameters. This data allows one to calculate the lengths, moment arms, forces, and joint moments generated by forty three muscles of the lower limb. The data set is presented in several files. 

The "Muscle_input_file" includes:
(1) a dimensionless force-length curve for tendon,
(2) dimensionless force-length curves for muscle,
(3) a dimensionless force-velocity curve for muscle,
(4) definitions of forty-three lower limb muscles. The definition of each muscle contains a list of coordinates that describe its line of action and the parameters (peak isometric force, optimal fiber length, tendon slack length, and pennation angle) needed to compute isometric muscle force. A more readable summary of musculotendon parameters is given in a separate table.

The "Joint_kinematic_file" includes kinematic descriptions of the hip, knee, ankle, subtalar, and metatarsophalangeal joints.

The "bones directory" includes approximate surface geometry for the bones of the lower limb. The format of these files is described in a file called "bone file format." You can download surface geometry for the pelvisfemurpatellatibiafibulatalusfoot, and toes. The patella, tibia, fibula, and bones of the foot were provided by Don Stredney of the Ohio State University.

FORMAT OF THE DATA SET

The data set is organized according to the structure of the input files for SIMM (Software for Interactive Musculoskeletal Modeling). An overview of this software and file formats is given in Delp, S.L. and Loan, J.P.: A software system to develop and analyze models of musculoskeletal structures, Computers in Biology and Medicine, vol. 25, pp. 21-34, 1995.

LIMITATIONS OF THE MODEL

There are several important limitations of the computer model described by this data set. The computer model represents a normal, adult male and is based on parameters that were compiled in several different experimental studies. The details of the lower limb model and some of its limitations are described in the publications listed below. USERS OF THIS DATA MUST TAKE THE RESPONSIBILITY TO TEST AND EVALUATE THE ACCURACY OF THE MODEL IN THE CONTEXT OF THEIR APPLICATION. DOWNLOADING THE DATA REPRESENTS AGREEMENT TO DO THIS.

Delp, S.L., Loan, J.P., Hoy, M.G., Zajac, F.E., Topp E.L., Rosen, J.M.: An interactive graphics-based model of the lower extremity to study orthopaedic surgical procedures, IEEE Transactions on Biomedical Engineering, vol. 37, pp. 757-767, 1990.

Delp, S.L.: Surgery simulation: a computer graphics system to analyze and design musculoskeletal reconstructions of the lower extremity, Ph.D. Dissertation, Stanford University, 1990. 

If you would like a copy of the dissertation please contact Scott Delp, Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Room 1406, 345 East Superior Street, Chicago, IL 60611, USA (This email address is being protected from spambots. You need JavaScript enabled to view it.).

APPLICATIONS OF THE MODEL

Variations on this model have been used in the analyses presented in a number of publications, including the ones listed below.

Arnold, A.A., Komattu, A.V., Delp, S.L.: Internal rotation gait: A compensatory mechanism to restore abduction ca pacity decreased by bone deformity? Developmental Medicine and Child Neurology, vol. 39, pp. 40-44, 1997.

Debski, R.E., Wong, E.K., Warner, J.J.P., Fu, F.H., Woo, S.L-Y.: Transactions of the capsuloligamentous restraints during translation of the glenohumeral joint. Transactions of the 42nd Annual Meeting, Orthopaedic Research So ciety, p. 230, 1996.

Delp, S.L. and Loan, J.P.: A software system to develop and analyze models of musculoskeletal structures, Com puters in Biology and Medicine, vol. 25, pp. 21-34, 1995.

Delp, S.L. and Maloney, W.J.: Effects of hip center location on the moment-generating capacity of muscles. Journal of Biomechanics. vol. 26, pp. 485-499, 1993.

Delp, S.L. and Zajac, F.E.: Force- and moment-generating capacity of lower-limb muscles before and after tendon lengthening. Clinical Orthopaedics and Related Research, vol. 284, pp. 247-259, 1992.

Delp, S.L., Arnold A.A., Speers, R.A., Moore, C.: Hamstrings and psoas lengths during normal and crouch gait: implications for muscle-tendon surgery. Journal of Orthopaedic Research, vol. 14, pp. 144-151, 1996.

Delp, S.L., Komattu, A.V., Wixson, R.L.: Superior displacement of the hip in total joint replacement: effects of pros thetic neck length, neck-stem angle, and anteversion angle on the moment-generating capacity of the muscles, Journal of Orthopaedic Research, vol. 12, pp. 860-870, 1994.

Delp, S.L., Loan, J.P., Hoy, M.G., Zajac, F.E., Topp E.L., Rosen, J.M.: An interactive graphics-based model of the lower extremity to study orthopaedic surgical procedures. IEEE Transactions on Biomedical Engineering, vol. 37, pp. 757-767, 1990.

Delp, S.L., Ringwelski, D., Carroll, N.C.: Transfer of the rectus femoris: effects of transfer site on moment arms about the knee and hip. Journal of Biomechanics vol. 27, pp. 1201-1211, 1994.

Delp, S.L., Statler, K., Carroll, N.C.: Preserving plantarflexion strength after surgical treatment for contracture of the triceps surae: a computer simulation study, Journal of Orthopaedic Research , vol. 13, pp. 96-104, 1995.

Free, S.A. and Delp, S.L.: Effects of trochanteric transfer on the moment arms, lengths, and force-generating ca pacities of the hip abductors. Journal of Orthopaedic Research, vol. 14, pp. 245-250, 1996. 

Gonzalez, R.V., Buchanan, T.S., Delp, S.L.: How muscle architecture and moment arms affect wrist flexion-exten sion moments. Journal of Biomechanics, vol. 30, pp. 705-712, 1997.

Keshner, E.A., Statler, K.D., Delp, S.L.: Kinematics of the freely moving head and neck in the alert cat, Experimental Brain Research, vol. 115, pp. 257-266, 1997.

Kim, A.W., Rosen, A.M., Brander, V.A., Buchanan, T.S.: Selective muscle activation following electrical stimulation of the collateral ligaments of the human knee, Archives Physical Medicine and Rehabilitation, vol. 76, pp. 750-757, 1995.

Lloyd, D.G. and Buchanan, T.S.: A model of load sharing between muscles and soft tissues at the human knee dur ing static tasks, Journal of Biomechanical Engineering, vol. 118, pp. 367-376, 1996.

Murray, W.A., Delp, S.L., Buchanan, T.S.: Variation of muscle moment arms with elbow and forearm position, Jour nal of Biomechanics, vol. 28, pp. 513-525, 1995.

Piazza, S.J. and Delp, S.L.: Influence of muscles on knee flexion during the swing phase of normal gait. Journal of Biomechanics, vol. 29, pp. 723-733, 1996.

Vasavada, A.N., Delp, S.L., Maloney, W.J., Schurman, D.J., Zajac, F.E.: Compensating for changes in muscle length in total hip arthroplasty: effects on the moment-generating capacity of the muscles. Clinical Orthopaedics and Related Research, vol. 302, pp. 121-133, 1994.

Yamaguchi, G.T., Moran, D.W., Si, J.: A computationally efficient method for solving the redundant problem in bio mechanics, Journal of Biomechanics, vol. 28, pp. 999-1005, 1995.