This paper presents a component mode synthesis approach to estimate tibial strains in gait. First, 3D models of the human musculoskeletal system were constructed based on the China Visible Human (CVH) dataset. Then an experiment was carried out to capture the subject gait motion. An inverse dynamic algorithm was developed to predict joint moments and an optimization algorithm was used to predict muscle forces in subject gait. Finally, a finite element model of the tibia was built. The muscle forces were input into the tibia finite element model as boundary conditions. Through the proposed component mode synthesis approach, 12 mode shapes and strains of tibia were estimated. The maximum and minimum principal strain magnitudes of tibia are 499 microstrain and -612 microstrain respectively. The maximum and minimum strain rates of tibia are 4130 microstrain s(-1) and -3970 microstrain s(-1) respectively. These figures are in line with literature values from in vivo measurements using an invasive strain gauge. In conclusion,the component mode synthesis approach may be used as a surrogate for experimental bone strain measurements and thus be of use in detailed strain estimation of bones indifferent applications.