For those of you that keep asking ~ Keep in mind that the color changes from brand to brand. Pay more attention to how WIDE the band is. Now you know exactly how much resistance there is!
Red – XX-Light – ½” Wide Primarily used for adding resistance to stretching exercises. Resistance is 5 – 35 pounds.
Purple – X-Light – 1 1/8″ wide Good choice as a general use band and a specifically for adding resistance to people under 140 pounds during walks, high knees, or sprints. Resistance is 25 – 80 pounds.
Green – Light – 1 ¾” wide This band is also a good size for general use and for adding resistance to people from 140 to 200 pounds for body movements. Good choice for pull up training. Resistance is 50 – 120 pounds.
Blue – Medium – 2 ½” wide For use getting started on training for bodyweight pull ups and adding resistance for elite athletes and people over 200 pounds. Also a good choice for adding increment weight to power lifts. Resistance 60 – 150 pounds.
Orange – Heavy – 3 ¼” wide Primarily used for adding weight to power lifts. Resistance is 70 to 175 pounds.
Black – X-Heavy – 4″ wide The BIG DOG band for power lifts. Resistance is 80 to 200 pounds.
Information shared from Rep Fitness a Longmont, CO based strength and conditioning warehouse
Photo courtesy of T Nation