The disproportionate loss of muscle force in comparison to loss of muscle mass with age remains unexplained. Recent studies indicate that the remodeling of the extracellular matrix (ECM) may disrupt lateral force transmission pathways mediated by the ECM. Shear strain is the mechanism that supports lateral transmission of force. We quantified shear strain in muscle from the strain rate tensor derived from velocity encoded phase contrast dynamic images of the in-vivo human calf muscle under isometric contractions. The maximal shear strain was significantly lower in the older cohort compared to the younger cohort which potentially identifies that lateral force transmission decreases with age.