Most people who go from conventional running shoes to barefoot or minimalist footwear, will at some point, feel their calves; and some will feel them rather a lot. A couple of factors cause this:
• Increased heel drop: Conventional shoes normally raise your heel 15-22mm relative to the ball of the foot. This lets you get away with (and possibly even encourages) stiff ankle joints and tight calf muscles.
• Impact: Moving away from heel-strike towards a fore/mid foot landing results in relatively more work from your calf (rather than shin and knee)
So now your calves are required to lengthen more and work harder than they ever have. A little tape often helps whilst the muscles get used to their new role.
Watch video on Youtube: Active Stretch For Achilles Tendon For Better Ankle & Calf Flexibility