Plank Challenge 4 minutes
Bo Kalvslund
Health & Fitness
BUILD TO A 4-MINUTE PLANK IN 5 WEEKS Transform your core with the Plank Challenge – a proven 5-week program that takes you from beginner to holding a 4-minute plank. THE CHALLENGE Week 1: Start with short holds Week 5: Achieve a 4-minute plank No gym. No equipment.