EE was getting drafts and walking along the stern side of Barge #SL-409. EE attempted to step over a cable that was left in the walkway when their boot caught the cable and tripped them causing them to over extend the right calf and Achilles tendon. As of the date of this report, BUU is questioning if this is a pre-existing condition. MRI is being scheduled; off work 9/3/17.