Movement has its own place on the skirmish board. It gets a little sticky when dividing movement into skills, though. Here, I think the 5e definitions help out quite a bit. To summarize and adapt: Strength-Athletics allows you to overcome perceived obstacles and unusual terrain, involving climbing, jumping, running, and swimming; Dexterity-Acrobatics allows you to react to unperceived obstacles and unusual circumstances in terrain. For purposes of defending in combat, it is the “reaction” part that I wish to emphasize.
Defensive movement has works in combat by: using/creating cover, using/creating concealment, or moving unpredictably. Concealment matches Stealth. Cover can be used by either Stealth or Acrobatics. Unpredictable movement (dodging) matches well with Acrobatics.
This makes the combat movement skills: Dexterity-Stealth (take cover, hide) and Dexterity-Acrobatics (take cover, dodge). It also means that Strength-Athletics may apply to battlefield terrain, but is not used to directly, defensively influence the opponent’s roll.