We used a 0.5T upright open MRI to investigate T2 as a marker for muscle activity. Six volunteers’ arms were imaged with a Double Echo Steady State (DESS) sequence while relaxing (30min), following weighted bicep curls, and again after relaxing (20min). Directly after bicep curls T2 increased (average 41%) in the biceps but not the triceps, then subsequently decreased (average 14%) with relaxing. Intra-rater repeatability was promising. T2 standard deviation was relatively high, which is likely due to tissue heterogeneity. This preliminary study supports the potential of using DESS in upright open MRI to assess muscle injury or dysfunction.