A system and method for conditioning a tissue are provided. The system includes a substrate, a plurality of microwells formed in the substrate, and a microsphere associated with each of the plurality of microwells. The system also includes a pair of flexible pillars within each of the plurality of microwells. Each flexible pillar includes a first end bonded to a respective microwell and at least one flexible pillar has a second end bonded to the microsphere. The flexible pillars are configured to deflect when exposed to a magnetic field to controllably stretch microtissue spanning the flexible pillars.