We develop open source software tools, including OpenSim and Simbody, which enable scientists to develop and share accurate models and simulations of musculoskeletal structures and other dynamic systems. Through Simtk, we provide an online platform for the worldwide biomedical community to exchange their software, models, and simulations.

Related Publications

• Uchida, T.K., Seth, A., Pouya, S., Dembia, C.L., Hicks, J.L., Delp, S.L. Simulating ideal assistive devices to reduce the metabolic cost of running. PLOS ONE, 11(9):e0163417, 2016. Download PDF Document

• Rajagopal, A., Dembia, C.L., DeMers, M.S., Delp, D.D., Hicks, J.L., Delp, S.L. Full body musculoskeletal model for muscle-driven simulation of human gait. IEEE Transactions on Biomedical Engineering, Vol. 63 (9), 2016. Download PDF file

• Lerner F.Z., DeMers M.S., Delp S.L., Browning R.C. How tibiofemoral alignment and contact locations affect predictions of medial and lateral tibiofemoral contact forces. Journal of Biomechanics, 48, 2015. Download PDF Document

• Uchida, T.K., Hicks, J.L., Dembia, C.L., Delp, S.L. Stretching your energetic budget: how tendon compliance affects the metabolic cost of running. PLOS ONE, 11(3):e0150378, 2016. Download PDF Document

• Seth A., Matias R., Veloso A.P., Delp S.L. A Biomechanical Model of the Scapulothoracic Joint to Accurately Capture Scapular Kinematics during Shoulder Movements. PLoS ONE, 11(1): e0141028, 2016. Download PDF Document. PloS ONE HTML page 

• Ong, C.F., Hicks, J.L., Delp, S.L. Simulation-Based Design for Wearable Robotic Systems: An Optimization Framework for Enhancing a Standing Long Jump. IEEE Transactions on Biomedical Engineering, in press. Download PDF Document

• Hutchinson, J.R., Rankin, J.W., Rubenson, J., Rosenbluth, K.H., Siston, R.A., Delp, S.L. Musculoskeletal modelling of an ostrich (Struthio camelus) pelvic limb: influence of limb orientation on muscular capacity during locomotion. Peer J, vol 3, pp e1001. Download PDF Document

• Dorn, T. W., Wang, J. M., Hicks, J. L., Delp, S. L.. Predictive simulation generates human adaptations during loaded and inclined walking. PloS one, 10(4). Download PDF Document

• Uchida, T.K., Sherman, M.A., Delp, S.L. Making a meaningful impact: modelling simultaneous frictional collisions in spatial multibody systems. Proceedings of the Royal Society of London A: Mathematical, Physical and Engineering Sciences 471(2177):20140859, 2015. Download PDF Document

• Scholz, A., Sherman, M., Stavness, I., Delp, S., Kecskeméthy, A. A fast multi-obstacle muscle wrapping method using natural geodesic variations. Multibody System Dynamics, 1-25 Download PDF Document

We lead the Mobilize Center, whose mission is to harness the vast amounts of data that have been collected by hundreds of research labs and millions of wearable sensors to improve human movement across the wide range of conditions that limit mobility, including cerebral palsy, osteoarthritis, obesity, and running injuries.

Related Publications

• Ferber, R., Osis, S.T., Hicks, J.L., Delp, S.L. Gait biomechanics in the era of data science. Journal of Biomechanics, in press, 2016. Download PDF file

• Ku, J.P., Hicks, J.L., Hastie, T., Leskovec, J., Re, C., Delp, S.L. The mobilize center: an NIH big data to knowledge center to advance human movement research and improve mobility. Journal of the American Medical Informatics Association, vol 22, pp 1120-1125. Download PDF Document

• Hicks, J.L., Delp, S.L., Schwartz, M.H. Can biomechanical variables predict improvement in crouch gait? Gait and Posture, vol 34, pp 197-201. Download PDF Document

• Reinbolt, J.A., Fox, M.D., Schwartz, M.H., Delp, S.L. Predicting outcomes of rectus femoris transfer surgery, Gait & Posture, vol 30, pp 100-105. Download PDF Document

We develop and use advanced medical imaging techniques to determine muscle and bone geometry, measure in vivo joint and muscle motion, and characterize muscle architecture. We have designed and built an optical imaging system for capturing individual human sarcomeres from nearly any location in the body.

Related Publications

• Chen, X., Sanchez, G.N., Schnitzer, M.J., Delp, S.L. Changes in sarcomere lengths of the human vastus lateralis muscle with knee flexion measured using in vivo microendoscopy Journal of Biomechanics, in press. Download PDF file

• Wentland, A.L., McWalter, E.J., Pal, S., Delp, S.L. and Gold, G.E., Muscle velocity and inertial force from phase contrast MRI. Journal of Magnetic Resonance Imaging, 42(2),2015. Download PDF Document

• Sanchez, G.N., Sinha, S., Liske, H., Chen, X., Nguyen, V., Delp, S.L., Schnitzer, M.J. In Vivo Imaging of Human Sarcomere Twitch Dynamics in Individual Motor Units. Neuron, vol 88, pp 1109-1120. Download PDF Document

• Keenan, K.E., Besier, T.F., Pauly, J.M., Smith, R.L., Delp, S.L., Beaupre, G.S., Gold, G.E.. T1rho dispersion in articular cartilage: relationship to material properties and macromolecular content. Cartilage, 6(2), 113-122
  Download PDF Document

• Cosgrove, B.D., Gilbert, P.M., Porpiglia, E., Mourkioti, F., Lee, S.P., Corbel, S.Y., Llewellyn, M.E., Delp, S.L., Blau, H.M. Rejuvenation of the muscle stem cell population restores strength to injured aged muscles. Nature Medicine, vol 20, pp 255-264. Download PDF Document

• Cromie, M.J., Sanchez, G.N., Schnitzer, M.J., Delp, S.L. Sarcomere lengths in human extensor carpi radialis brevis measured by microendoscopy. Muscle & Nerve, vol 8, pp 286-292. Download PDF Document

• Pal, S., Besier, T.F., Beaupre, G.S., Fredericson, M., Delp, S.L., Gold, G.E. Patellar maltracking is prevalent among patellofemoral pain subjects with patella alta: an upright, weightbearing MRI study. Journal of Orthopaedic Research, vol 31, pp 448-457. Download PDF Document

• Draper, C.E., Quon, A., Fredericson, M., Besier, T.F., Delp, S.L., Beaupre, G.S., Gold, G.E. Comparison of MRI and 18F-NaF PET/CT in patients with patellofemoral pain. Journal of Magnetic Resonance Imaging, vol 36, pp 928-932. Download PDF Document

• Chen, C.A., Chen, W., Goodman, S.B., Hargreaves, B.A., Koch, K.M., Lu, W., Brau, A.C., Draper, C.E., Delp, S.L., Gold, G.E. New MR imaging methods for metallic implants in the knee: artifact correction and clinical impact. Journal of Magnetic Resonance Imaging, vol 33, pp 1121-1127. Download PDF Document

• Keenan, K.E., Besier, T.F., Pauly, J.M., Han, E., Rosenberg, J., Smith, R.L., Delp, S.L., Beaupré, G.S., Gold, G.E. Prediction of glycosaminoglycan content in human cartilage by age, T1rho and T2 MRI. Osteoarthritis and Cartilage, vol 19, pp 171-179. Download PDF Document

We apply optogenetics to control neural activity in the peripheral nervous system. We have achieved light-mediated activation of motor neurons to stimulate muscle contraction, and we are developing methods for inhibition of neural activity to control spasticity and pain.

Related Publications

• Christensen, A.J., Iyer, S.M., Francois, A., Vyas, S., Ramakrishnan, C., Vesuna, S., Deisseroth, K., Scherrer, G., Delp, S.L. In vivo interrogation of spinal mechanosensory circuits. Cell Reports, 17:1699-1710, 2016. Download PDF file

• Iyer, S.M., Vesuna, S., Ramakrishnan, C., Huynh, K., Young, S., Berndt, A., Lee, S.Y., Gorini, C.J., Deisseroth, K., Delp, S.L. Optogenetic and chemogenetic strategies for sustained inhibition of pain Scientific Reports, 6:30570 Download PDF file

• Ferenczi E.A., Vierock J., Atsuta-Tsunoda K., Tsunoda S.P., Ramakrishnan C., Gorini C., Thompson K., Lee S.Y., Berndt A., Perry C., Minniberger S., Vogt A., Mattis J., Prakash1 R., Delp S.L., Deisseroth K., Peter Hegemann. Optogenetic approaches addressing extracellular modulation of neural excitability. Scientific reports, 6, 2016. Download PDF Document

• Berndt A., Lee S.Y., Wietek J., Ramakrishnan C., Steinberg E.E., Rashid A.J., Kim H., Park S., Santoro A., Frankland P.W., Iyer S.M., Pak S., Ahrlund-Richter S., Delp S.L., Malenka R.C., Josselyn S.A., Carlen M., Hegemann P., Deisseroth K. Structural foundations of optogenetics: Determinants of channelrhodopsin ion selectivity. Proceedings of the National Academy of Sciences, 201523341, 2015. Download PDF Document

• Montgomery, K.L., Iyer S.M., Christensen A.J., Deisseroth K., Delp S.L. Beyond the brain: Optogenetic control in the spinal cord and peripheral nervous system. Science Translational Medicine, 8(337), 337rv5-337rv5, 2016. Download PDF Document

• Montgomery, K.L., Yeh, A.J., Ho, J.S., Tsao, V., Iyer, S.M., Grosenick, L., Ferenczi, E.A., Tanabe, Y., Deisseroth, K., Delp, S.L., Poon, A.S.Y. Wirelessly powered, fully internal optogenetics for brain, spinal and peripheral circuits in mice. Nature Methods, vol 12, pp 969-974.  Download PDF Document

• Iyer, S.M., Delp, S.L. Optogenetic Regeneration. Science, vol 344, pp 44-45. Download PDF Document

• Iyer, S.M., Montgomery, K.L., Towne, C., Lee, S.Y., Ramakrishnan, C., Deisseroth, K., Delp, S.L. Virally mediated optogenetic excitation and inhbition of pain in freely moving nontransgenic mice. Nature Biotechnology, vol 32, pp 274-278. Download PDF Document

• Delp, S.L. Studying Circuits with Therapy in Mind: Therapy for the Periphery. Cell, vol 156, pp 862. Download PDF Document

• Liske, H., Qian, X., Anikeeva, P., Deisseroth, K., Delp, S. Optical control of neuronal excitation and inhibition using a single opsin protein, ChR2. Scientific Reports, vol 3 . Download PDF Document

We use musculoskeletal modeling, dynamic simulations, motion capture experiments, and medical imaging to create an integrated understanding of human movement, explain the biomechanical causes of movement abnormalities, and predict the functional consequences of interventions like surgery and assistive devices.

Related Publications

• DeMers, M.S., Pal, S., Delp, S.L. Changes in tibiofemoral forces due to variations in muscle activity during walking. Journal of Orthopaedic Research, vol 32, pp 769-776. Download PDF Document

• Arnold, E.M., Hamner, S.R., Seth, A., Millard, M., Delp, S.L. How muscle fiber lengths and velocities affect muscle force generation as humans walk and run at different speeds. Journal of Experimental Biology, vol 216, pp 2150-2160. Download PDF Document

• Steele, K.M., Seth, A., Hicks, J.L., Schwartz, M.H., Delp, S.L. Muscle contributions to vertical and fore-aft accelerations are altered in subjects with crouch gait. Gait and Posture, vol 38, pp 86-91. Download PDF Document

• Steele, K.M., Damiano, D.L., Eek, M.N., Unger, M., Delp, S.L. Characteristics associated with improved knee extension after strength training for individuals with cerebral palsy and crouch gait. Journal of Pediatric Rehabilitation Medicine, vol 5, pp 99-106. Download PDF Document

• Steele, K.M., DeMers, M.S., Schwartz, M.H., Delp, S.L. Compressive tibiofemoral force during crouch gait. Gait & Posture, vol 35, pp 556-560. Download PDF Document

• Arnold, E.M., Delp, S.L. Fibre operating lengths of human lower limb muscles during walking. Philosophical Transactions of the Royal Society B, vol 366, pp 1530-1539. Download PDF Document

• Hicks, J.L., Schwartz, M.H., Arnold, A.S., Delp, S.L. Crouched postures reduce the capacity of muscles to extend the hip and knee during the single-limb stance phase of gait. Journal of Biomechanics, vol 41, pp 960-967. Download PDF Document

We use three-dimensional kinematics and forces, electromyography, and calorimetry to characterize the dynamics of movement and identify new ways to optimize human performance and prevent injury, such as gait retraining through haptic feedback.

Related Publications

• Uhlrich, S.D., Silder, A., Beaupre, G.S., Shull, P.B., Delp, S.L. Subject-specific toe-in or toe-out gait modifications reduce the larger knee adduction moment peak more than a non-personalized approach. Journal of Biomechanics 66, 103–110, January 3, 2018. Epub 2017 Download PDF file

• Thompson, J.A., Tran, A.A., Gatewood, C.T., Shultz, R., Silder, A., Delp, S.L., Dragoo, J.L.  Biomechanical Effects of an Injury Prevention Program in Preadolescent Female Soccer Athletes.  Am J Sports Med. 2017 Feb;45(2):294-301. doi: 10.1177/0363546516669326. Epub 2016 Oct 29. Download PDF.

• Thompson-Kolesar, J.A., Gatewood, C.T., Tran, A.A., Silder, A., Shultz, R., Delp, S.L., Dragoo, J.L.  Age Influences Biomechanics Changes After Participation in an Anterior Cruciate Ligament Injury Program.  Am J Sports Med. 2018 doi.org/10.1177/0363546517744313. Epub 2017 Dec 27. Download PDF.

• Silder, A., Besier, T., Delp, S.L. Running with a load increases leg stiffness. Journal of Biomechanics, 48 (6) Download PDF Document

• Yong, J.R., Silder, A., Delp, S.L. Differences in muscle activity between natural forefoot and rearfoot strikers during running. Journal of Biomechanics, vol 47, pp 3593-3597. Download PDF Document

• Shull, P.B., Silder, A., Shultz, R., Dragoo, J.L., Besier, T.F., Delp, S.L., Cutkosky, M.R. Six-week gait retraining program reduces knee adduction moment, reduces pain, and improves function for individuals with medial compartment knee osteoarthritis. Journal of Orthopaedic Research, vol 31, pp 1020-1025. Download PDF Document

• Shull, P.B., Shultz, R., Silder, A., Dragoo, J.L., Besier, T.F., Cutkosky, M.R., Delp, S.L. Toe-in gait reduces the first peak knee adduction moment in patients with medial compartment knee osteoarthritis. Journal of Biomechanics, vol 46, pp 122-128. Download PDF Document

• Silder, A., Besier, T., Delp, S.L. Predicting the metabolic cost of incline walking from muscle activity and walking mechanics. Journal of Biomechanics, vol 45, pp 1942-49. Download PDF Document

• Besier, T.F., Fredericson, M., Gold, G.E., Beaupre, G.S., Delp, S.L. Knee muscle forces during walking and running in patellofemoral pain patients and pain-free controls. Journal of Biomechanics, vol 42, pp 898-905. Download PDF Document

Anatomical studies

We have performed anatomical studies to measure muscle architecture, muscle moment arms, and joint kinematics.

• Murray, W. M., Buchanan, T.S., Delp, S.L. The isometric functional capacity of elbow muscles. Journal of Biomechanics, vol. 33, pp. 943-952, 2000. Download PDF Document

Strength and Coordination Measurements

We have studied the activation patterns of muscles in unimpaired subjects and in subjects with movement abnormalities by securing the limb to a load cell, asking subjects to match target loads displayed on a computer monitor, and recording the subjects’ EMG.

Surgical Navigation

We created and evaluated computer-integrated instrumentation that incorporates highly accurate measurement devices to locate joint centers, track surgical tools, and align prosthetic components.

• Delp, S.L., Loan, J.P., Basdogan, C., Rosen, J.M. Surgical simulation: an emerging technology for emergency medical training. Presence: Teleoperators and Virtual Environments, vol. 6, pp. 147-159, 1997. Download PDF Document

Three-Dimensional Muscle Modeling

We developed a mechanics-based formulation for representing three-dimensional skeletal muscle architecture and geometry, including a nonlinear constitutive model for muscle and tendon and graphics-based modeling techniques to characterize the three-dimensional trajectories of muscle fibers from medical image data.

• Webb, J.D., Blemker, S.S., Delp, S.L. 3D finite element models of shoulder muscles for computing lines of actions and moment arms. Computer Methods in Biomechanics and Biomedical Engineering, pp 1-9. Download PDF Document

• Blemker, S.S., Delp, S.L. Three-Dimensional Representation of Complex Muscle Architectures and Geometries. Annals of Biomedical Engineering, vol 33, pp. 661–673, 2005. Download PDF Document

Modeling and Simulation of Molecular Motors

We developed tools for creating course-grained geometric models of protein structures, performing molecular dynamic simulations to estimate physical properties, and running forward dynamic simulations of myosin during its power stroke.

• Parker, D., Bryant, Z., Delp, S.L. Coarse-grained structural modeling of molecular motors using multibody dynamics, Cellular and Molecular Bioengineering, vol 2, pp 366-374. Download PDF Document