X’s are a great way to work on your zone 3 or zone 4 pacing (5-10km race pace) without over-stressing you physically and aerobically.  X’s work on turnover and neuromuscular response with limited physical stress.  They are a great way for runners who are out of shape or new to the sport to stimulate some upper end fitness.  X’s are a great entry workout to some harder threshold/aerobic capacity sessions.

Posted in: Running, Training