Published August 11, 2026 03:05AM<\/p>\n<\/div>\n
Joining a gym after years of working out at home is a humbling experience. Don\u2019t get me wrong, I knew how<\/i> to exercise. What I did not know was how to walk into a room full of equipment and make a single decision about what to do with any of it. After ten minutes of inclined treadmill walking (which is my workout of choice when I want to pretend I look as if I know what I\u2019m doing), I grabbed my things and left the gym so abruptly that I abandoned my car keys on the machine.<\/p>\n
After speed-walking to my car, I plopped in the driver\u2019s seat, grabbed my phone, and opened Instagram. I searched for \u201cgym routines,\u201d saved a dozen or so videos, and came back the next day with something resembling a plan. Nearly every trainer on social media, regardless of equipment, background, or follower count, was prescribing the same thing: three sets of ten reps. The interesting part is that they all seemed to chant three sets of ten reps<\/em> with the quiet authority of someone who has never once been asked to explain themselves.<\/p>\n With the help of exercise physiologists and digging into the science, I landed upon an answer to the question I kept asking myself when I got back into the gym: How many sets and reps should I be doing?<\/i> Here\u2019s what I found out.<\/p>\n Thomas DeLorme<\/a>, an Army doctor, is responsible for bringing the three-sets-of-ten-reps protocol to the world.<\/p>\n DeLorme, born in 1917, grew up in Birmingham, Alabama. At age 15, he was bedridden for four months with rheumatic fever<\/a> (a painful illness that causes inflammation in the joints), and he shrank to 140 pounds. He spent that time reading medical textbooks alongside issues of Strength and Health<\/i> magazine. He rebuilt his body through weightlifting, against the advice of his doctors who insisted that he rest, and went on to study medicine. In 1944, he began his official duties as a physician at Gardiner General Army Hospital in Chicago, Illinois, where he specialized in orthopedics.<\/p>\n The standard approach to rehabilitation at the time<\/a> was cautious to the point of passivity. Heat therapy and exercises with light or zero resistance (with lots of reps) were typical, but medical professionals said nothing was better for recovery than rest.<\/p>\n Soldiers could be prescribed bed rest for between six and nine months, which meant not having enough beds for hospital newcomers. One doctor, William Brady, who published a newspaper column during that era, vehemently disapproved of weightlifting, stating: \u201cExtreme effort is not desirable in any kind of physical training nor is it good for the heart.\u201d Though strength training for soldiers was normal, it was not common among those in the medical field. But DeLorme knew firsthand that strength training can rehabilitate people post-injury.<\/p>\n When Sergeant Walter Easley came to him after surgeons had told him his knee would never fully recover from a parachute-jumping injury, DeLorme suggested the complete opposite of what had been the recovery norm: adding resistance to exercises.<\/p>\n DeLorme built a primitive weight-training gym at Gardiner. Leg extensions looked like repeatedly lifting the legs while wearing iron boots, and leg curls were done with a handmade pulley system. DeLorme advised Easley to perform seven sets of ten reps with the maximum weight he could manage and then bump up the weights once he mastered the previous weight. Rinse and repeat. After just one month, Easley reported larger quads and no pain around the knee. Word of his recovery got out, and others were eager to put DeLorme\u2019s protocol to the test.<\/p>\n In 1948, DeLorme named his program \u201cProgressive Resistance Exercise,\u201d a phrasing coined by his wife. Then, both he and another doctor, Arthur Watkins, reduced the recommended number of seven sets of ten reps to three sets of ten reps. Why? After testing out fewer sets with patients, they found that seven sets was too ambitious and that three sets allowed people to take on heavier loads, thus building strength and bigger muscles faster. The first set was meant to be performed at a weight that\u2019s 50 percent of the person\u2019s ten-rep maximum (10RM), the second at 75 percent of 10RM, and the third set at 100 percent of 10RM. (As a real-world example, if the heaviest weight you can lift for ten reps with good form is 50 pounds, you would lift 25 pounds in set one, around 38 pounds in set two, and then 50 pounds in the final set.)<\/p>\n DeLorme and Watkins\u2019 1951 textbook titled Progressive Resistance Exercise, Technique and Medical Application<\/i> spread the three-sets-of-ten-reps protocol into physical therapy, coaching, and eventually every gym in the country.<\/p>\n Physical fitness culture historian Conor Heffernan describes in his blog Physical Culture Study<\/i> the attachment to three sets of ten as \u201cquasi-religious,\u201d noting that rep ranges almost universally resolve to round numbers divisible by two. \u201cWhen was the last time you heard someone promote four sets of eleven reps?\u201d he wrote in an article about the origins of the three-sets-of-ten-reps routine<\/a>.<\/p>\n Tom Holland<\/a>, an exercise physiologist with more than 30 years in\u00a0the fitness industry, has a direct answer for why three sets of ten reps\u00a0had such staying power in the fitness world. \u201cThree sets of ten is simple and easy to remember,\u201d he told Outside<\/i>. At some point, the prescription stopped needing a reason to exist.<\/p>\n Greg Nuckols<\/a>, an exercise physiologist and the founder of the coaching program Stronger by Science<\/a>,<\/em> reviewed the literature comparing low, moderate, and high-rep training on muscle growth and arrived at a conclusion that undermines the whole premise: \u201cThere\u2019s simply not a very big difference in muscle growth when comparing different rep ranges,\u201d Nuckols wrote in a blog post on his website\u00a0about muscle hypertrophy<\/a>. Muscle growth is driven by two mechanisms, according to Nuckols.\u00a0The first is mechanical tension from heavier loads with fewer reps, and the second is metabolic stress from lighter loads with more reps. Both work.<\/p>\n That said, the recipe of three sets of ten reps isn\u2019t quite necessary for muscle growth. \u201cDeLorme would have found similar success using 2\u00d715 or 4\u00d78 protocols with adequate resistance,\u201d Holland told me.<\/p>\nAn Army Doctor\u2019s Protocol Led to Our Obsession with Strength Training<\/h2>\n
Bed Rest, According to Doctors of the Time, Was Better Than Exercise<\/h3>\n
How 3 Sets of 10 Reps Became Cemented in the Fitness World<\/h2>\n
What Made 3 Sets of 10 Reps Stick?<\/h2>\n
Is 3 Sets of 10 Reps Really the Magic Formula We Think It Is?<\/h2>\n