Evaluation of an EMG-Driven Model and Its Ability to Estimate Joint Moments At the Knee

To better understand the influence joint mechanics may have on the development or progression of joint degenerative diseases such as knee osteoarthritis (OA), EMG-driven models have been developed to estimate in-vivo muscle forces that contribute to the internal joint mechanics. However, there is a limited understanding of the model’s ability to estimate joint mechanics during stair ascent and stair descent, which induce larger joint loads that may contribute to the development or progression of knee OA. In addition, the model’s ability to estimate the joint moment when only one trial is used during the tuning process is also unknown. Therefore, the ability to estimate the flexion/extension (F/E) knee joint moment during walking, stair ascent, and stair descent with an EMG-driven model was evaluated. In addition the influence of using a single trial to tune the model was evaluated.

Knee joint kinematics for five healthy subjects were measured using motion capture during walking, stair ascent, and stair descent. The muscle-tendon lengths and moment arms of 11 muscles crossing the knee were then determined from an anatomical model of the lower leg. The muscle-tendon lengths and respective EMG signals served as inputs to the EMG-driven model. The model consisted of a neural activation component to estimate the muscle activation and a muscle contraction dynamics component that was based on a modified Hill-type model. The tuning process adjusted specific muscle properties to minimize the difference between the F/E knee joint moment determined from inverse dynamics and the moment estimated by the model. Only one trial of a given task was used during the tuning process. The resulting muscle parameters were then used to predict the joint moment for trials of the same task that were not used in the tuning process.

The estimated F/E knee joint moment exhibited the smallest RMS error and largest coefficient of determination during stair ascent, followed by walking, and stair decent. Overall, the trial used during the tuning process did not appear to influence the model's ability to estimate the joint moment for walking, stair ascent, or stair descent.

Year	Entry
1996	Piazza SJ, Delp SL. The influence of muscles on knee flexion during the swing phase of gait. J Biomech. June 1996;29(6):723-733.
2003	Lloyd DG, Besier TF. An EMG-driven musculoskeletal model to estimate muscle forces and knee joint moments in vivo. J Biomech. June 2003;36(6):765-776.
1983	Grood ES, Suntay WJ. A joint coordinate system for the clinical description of three-dimensional motions: application to the knee. J Biomech Eng. May 1983;105(2):136-144.
2004	Buchanan TS, Lloyd DG, Manal K, Besier TF. Neuromusculoskeletal modeling: estimation of muscle forces and joint moments and movements from measurements of neural command. J Appl Biomech. November 2004;20(4):367-395.
2001	Neptune RR, Kautz SA, Zajac FE. Contributions of the individual ankle plantar flexors to support, forward progression and swing initiation during walking. J Biomech. November 2001;34(11):1387-1398.
2002	Hurwitz DE, Ryals AB, Case JP, Block JA, Andriacchi TP. The knee adduction moment during gait in subjects with knee osteoarthritis is more closely correlated with static alignment than radiographic disease severity, toe out angle and pain. J Orthop Res. January 2002;20(1):101-107.
1997	Glitsch U, Baumann W. The three-dimensional determination of internal loads in the lower extremity. J Biomech. November–December 1997;30(11-12):1123-1131.
1990	Winters JM. Hill-based muscle models: a systems engineering perspective. In: Winters JM, Woo SL-Y, eds. Multiple Muscle Systems: Biomechanics and Movement Organization. New York, NY: Springer-Verlag; 1990:69-93.
2004	Andriacchi TP, Mündermann A, Smith RL, Alexander EJ, Dyrby CO, Koo S. A framework for the in vivo pathomechanics of osteoarthritis at the knee. Ann Biomed Eng. March 2004;32(3):447-457.
1990	Yamaguchi GT, Sawa AGU, Moran DW, Fessler MJ, Winters JM. A survey of human musculotendon actuator parameters. In: Winters JM, Woo SL-Y, eds. Multiple Muscle Systems: Biomechanics and Movement Organization. New York, NY: Springer-Verlag; 1990:717-773.
2000	Felson DT, Lawrence RC, Dieppe PA, Hirsch R, Helmick CG, Jordan JM, Kington RS, Lane NE, Nevitt MC, Zhang Y, Sowers M, McAlindon T, Spector TD, Poole AR, Yanovski SZ, Ateshian G, Sharma L, Buckwalter JA, Brandt KD, Fries JF. Osteoarthritis: new insights, I: the disease and its risk factors. Ann Intern Med. October 17, 2000;133(8):635-646.
1990	Zahalak GI. Modeling muscle mechanics (and energetics). In: Winters JM, Woo SL-Y, eds. Multiple Muscle Systems: Biomechanics and Movement Organization. New York, NY: Springer-Verlag; 1990:1-23.
2002	Zajac FE, Neptune RR, Kautz SA. Biomechanics and muscle coordination of human walking, I: introduction to concepts, power transfer, dynamics and simulations. Gait Post. December 2002;16(3):215-232.
1993	Cole GK, Nigg BM, Ronsky JL, Yeadon MR. Application of the joint coordinate system to three-dimensional joint attitude and movement representation: a standardization proposal. J Biomech Eng. November 1993;115(4A):344-349.
2003	Thelen DG, Anderson FC, Delp SL. Generating dynamic simulations of movement using computed muscle control. J Biomech. March 2003;36(3):321-328.
1966	Gordon AM, Huxley AF, Julian FJ. The variation in isometric tension with sarcomere length in vertebrate muscle fibres. J Physiol. 1966;184(1):170-192.
1981	Crowninshield RD, Brand RA. A physiologically based criterion of muscle force prediction in locomotion. J Biomech. 1981;14(11):793-801.
1992	Schutte LM. Using Musculoskeletal Models to Explore Strategies for Improving Performance in Electrical Stimulation-Induced Leg Cycle Ergometry [PhD thesis]. Stanford University; 1992.
1980	Spector SA, Gardiner PF, Zernicke RF, Roy RR, Edgerton VR. Muscle architecture and force-velocity characteristics of cat soleus and medial gastrocnemius: implications for motor control. J Neurophysiol. November 1980;44(5):951-960.
1989	Zajac FE. Muscle and tendon: properties, models, scaling, and application to biomechanics and motor control. Crit Rev Biomed Eng. 1989;17(4):359-411.
1985	Olney SJ, Winter DA. Predictions of knee and ankle moments of force in walking from EMG and kinematic data. J Biomech. 1985;18(1):9-20.
1994	Goffe WL, Ferrier GD, Rogers J. Global optimization of statistical functions with simulated annealing. J Econom. January–February 1994;60:65-99.
1990	Delp SL, Loan JP, Hoy MG, Zajac FE, Topp EL, Rosen JM. An interactive graphics-based model of the lower extremity to study orthopaedic surgical procedures. IEEE Trans Biomed Eng. 1990;37(8):757-767.
2001	Kaufman KR, Hughes C, Morrey BF, Morrey M, An K-N. Gait characteristics of patients with knee osteoarthritis. J Biomech. July 2001;34(7):907-915.
1996	Lloyd DG, Buchanan TS. A model of load sharing between muscles and soft tissues at the human knee during static tasks. J Biomech Eng. August 1996;118(3):367-376.
1995	Delp SL, Loan JP. A graphics-based software system to develop and analyze models of musculoskeletal structures. Comput Biol Med. January 1995;25(1):21-34.

Year

Entry

1996

Piazza SJ, Delp SL. The influence of muscles on knee flexion during the swing phase of gait. J Biomech. June 1996;29(6):723-733.

2003

Lloyd DG, Besier TF. An EMG-driven musculoskeletal model to estimate muscle forces and knee joint moments in vivo. J Biomech. June 2003;36(6):765-776.

1983

Grood ES, Suntay WJ. A joint coordinate system for the clinical description of three-dimensional motions: application to the knee. J Biomech Eng. May 1983;105(2):136-144.

2004

Buchanan TS, Lloyd DG, Manal K, Besier TF. Neuromusculoskeletal modeling: estimation of muscle forces and joint moments and movements from measurements of neural command. J Appl Biomech. November 2004;20(4):367-395.

2001

Neptune RR, Kautz SA, Zajac FE. Contributions of the individual ankle plantar flexors to support, forward progression and swing initiation during walking. J Biomech. November 2001;34(11):1387-1398.