Read this tip to make your life smarter, better, faster and wiser. LifeTips is the place to go when you need to know about Fitness Training and other Muscle Building topics.
There are some general rules about strength ratios between opposing muscle groups. Quads are supposed to be stronger than hamstrings in a ratio of 3:2, so that if you can do a leg extension of 60 lb, your best hamstring curl should be 40 lb. If your best extension is 120 lb, your curl should be 80 lb. Biceps and triceps are supposed to be 1:1, though this can be hard to test with common exercises. Trunk flexion (abs and hip flexors) and spinal erectors are also supposed to be even.