Building weekly running mileage for a half marathon requires patience and a structured approach to avoid overuse injuries. The widely accepted 10-percent rule, which limits weekly mileage increases to 10 percent, remains a solid guideline for most runners, though beginners should be even more conservative with five to eight percent jumps.
A smart 12-week buildup starts with your current comfortable weekly mileage and incorporates a step-back week every fourth week, reducing volume by 20 to 30 percent to allow recovery and adaptation. Long runs should increase by no more than one mile per week and never exceed 30 percent of your total weekly volume.
Supplementing running with two days of cross-training and dedicated mobility work further reduces injury risk while building the aerobic base needed for race day success.
