The injury mechanics and strain distribution in the glenohumeral capsule at a particular joint angle have been studied extensively. However, there is a lack of information on the strain distributions in the capsule under complex joint angles, i.e, during the activities of daily living(ADL). To investigate the mechanical response of the capsule under the kinematics of the forward reach, a subject specific finite element model of the glenohumeral joint with the capsule was developed. Since the mechanical properties of the capsule under multiaxial loading were unknown we proposed an inverse finite elements based optimization routine to determine the material coefficients of the capsule. Several constitutive material models were evaluated to identify feasibility of convergence for the complex loading associated with physiological tasks. We established limits for the material coefficients of the Mooney-Rivlin model used to model the capsule. The Mooney-Rivlin model with the material coefficients C₁ = 6, C₁₀ = 6.5, and D₁ = 0.12 converged for around 50% of the cycle. The results also suggest that the peak strain occurred on the inferior aspect of both the anterior and posterior side of the capsule. This work serves as the basis for future comparisons of material models and can be extended to other activities of daily living.