If you have spent any time in a gym in 2026, you have probably seen someone sitting on the floor with both knees bent at right angles, one leg in front and one to the side, looking like they are not sure what to do next. That is the 90/90, and it is the position that physical therapists have been quietly recommending to lifters for years. The internet finally caught on this spring, and the search volume on the term has jumped sharply since February.
The position itself is simple. Sit on the floor, bend your front leg ninety degrees with the shin parallel to your body, and bend your back leg ninety degrees with the shin pointing out to the side. Your hips should be facing the front leg. The front hip is in external rotation. The back hip is in internal rotation. Most adults can barely hold the position without falling over. That is the point. It exposes a deficit that almost everyone has and almost no one trains.
Internal hip rotation is the range of motion the lifting world has ignored for two decades. The big mobility conversations during the CrossFit boom were about ankle dorsiflexion, thoracic extension, and hip flexor length. Internal rotation got mentioned occasionally and then dismissed. The cost of that gap shows up in two specific places. The first is the bottom of a squat, where insufficient internal rotation forces the femur to rely on the lumbar spine to find depth. The second is the cutting and pivoting demands of any field sport. Hockey players, soccer players, and basketball players who lose internal rotation in their thirties tend to develop hip impingement and sometimes need surgery.
The published research backs the focus on this position. A 2023 study in the Journal of Orthopaedic and Sports Physical Therapy found that adults under fifty had an average of 35 degrees of passive internal hip rotation. The functional minimum for an unrestricted bodyweight squat is closer to 40. The 90/90 trains both ranges in the same drill. A 2024 paper in the Strength and Conditioning Journal showed that twelve weeks of dedicated hip rotation work added an average of 8 degrees of internal rotation in trained lifters. That is meaningful for anyone trying to squat below parallel without compensating.
The credit for the recent surge belongs to a few specific coaches. Dr. Andreo Spina built his Functional Range Conditioning system around controlled articular rotations starting in 2014, and the 90/90 transitions are core to his hip work. Mike Boyle has been pushing the position for hockey players since the late 2000s. Kelly Starrett included it in The Supple Leopard, which sold over 400,000 copies. The newer wave is coming from Conor Harris and Pat Davidson, who built large social followings explaining hip biomechanics in plain language. Harris's videos on lower body rotation have crossed 60 million combined views since 2023.
There are several variations of the drill that matter for programming. The static hold is the entry version. Sit in the position and try to keep both sit bones on the floor for thirty to sixty seconds per side. Most people cannot do this without their back hip lifting. The transition adds rotation. From the 90/90, you rotate your torso and let your back leg swing through to the front while your front leg rotates back. The end position is the mirror of where you started. Three to five minutes of these transitions before squatting is what the strength coaches are programming.
The advanced version is loaded internal rotation. Sit in the 90/90 and lift the back leg off the floor by driving the inside of the knee down. This trains active range of motion, which is what shows up in athletic performance. Two seconds up, two seconds down, eight to ten reps per side. Add a kettlebell to the back foot for the strongest progression.
The crossover into general fitness is being driven by a new generation of physical therapists posting on Instagram and TikTok. The hashtag for hip mobility crossed 2.1 billion views this year, and the 90/90 specifically appears in roughly a quarter of those clips. Squat University, which has 4.8 million Instagram followers, published a four-part series on the position over the last six weeks that has generated significant engagement.