Complex sentence: Kirkman's first training sessions, at age 14, involved traveling to a south Seattle gymnasium to work out from his school in Renton, Washington, suggested to him by former professional Joey Velez.
Split into simpler sentences: Kirkman's first training sessions at age 14 involved traveling to a south Seattle gymnasium to work out from his school in Renton, Washington. The venue was suggested to him by former professional Joey Velez.