Thanks for requesting updated models. 2398Hip_w_LaiArnold is based heavily on the model by Lai and Arnold (https://pubmed.ncbi.nlm.nih.gov/28900782/) with modifications from 2396Hip and additional updates. This model can be used with younger populations and in deep hip and knee flexion activities. We added slides describing most modifications. We did not re-run all tests and checks of Lai or Shelburne. The user may re-run them.

The 2396Hip version of the hip muscle model combines muscle definitions from Shelburne's hip model and the baseline OpenSim 2392 model. Specifically, definitions for muscles spanning (1) the hip, (2) the hip and knee, and (3) the torso were derived from Shelburne. Muscles spanning only the knee and everything distal to the knee were derived from 2392.

NOTES ON THE HIP MODEL, Shelburne - August 2010 This model is intended for hip research - detail is focused on the muscles spanning the hip. The model is based on OpenSim example model 23DOF_72 with additional muscles and adjustments made by Kevin Shelburne. Muscles added: obturator, rectus abdominus. The knee geometry was taken from the OpenSim example model 23_54. Adjustments were made to the muscle geometry so that the moment arms of the model matched the measurements of Delp, Hess, Hungerford, Jones 1999; Jorgensen, Marras, Granata, Wiand 2001; Dostal, Soderberg, Andrews 1986; Nemeth and Olsen 1985. Wrapping objects were added for Gmax, Iliacus, and Psoas. Adjustments were made to muscle parameters so that the maximum isometric strength of the model matched the in vivo maximum torque measurements of Shelburne PhD Thesis 1997, Anderson PhD Thesis 1999, McGill and Hoodless 1980, McNeil, Warwick, Andersson, Schultz 1980. Overall, the strength of the model was increased by 20% from the original 23_54 OpenSim example model except for the muscles spanning the knee. These muscle strengths were matched to Shelburne and Pandy (2004). Please cite: Shelburne, K.B., Decker, M.J., Krong, J., Torry, M.R., Philippon, M.J., 2010. Muscle forces at the hip during squatting exercise. In: 56th Annual Meeting of the Orthopaedic Research Society. New Orleans, LA.