Although “no pain, no gain” is a bedrock principle and mantra for serious weight lifters, you may be relieved to know you can strengthen your muscles without getting horridly sore and walking around like a mummy. You do have to repeatedly stress your muscles beyond their customary capacity, but shredding them isn’t always necessary to turn on the genes that promote growth.43 If you primarily want to gain strength, you’ll get the most bang for your buck by slowly doing a few demanding repetitions of weights that require eccentric or isometric contractions.44
