Can a One Minute Wall Sit Really Work Like Cardio?
A wall sit does more than tire your legs. Here is what a 270-trial analysis found about isometric holds and blood pressure, and how to do one safely.
Chris Pruitt
Chris Pruitt is a certified ASFA personal trainer and the founder of WorkoutHealthy, a fitness equipment retailer serving customers since 2007. He has more than 16 years in the fitness business, and he writes and fact checks everything published on Insider.
The 30 Day Experiment That Made Muscle Grow 4 Times Faster
A viral fitness experiment found that training a muscle daily made it grow up to four times faster on MRI scans. Here is what the experiment actually tested, and what it does not prove.
One Mile Every 4:48, Thirteen Times Straight: The Half Marathon World Record
Letesenbet Gidey ran 1:02:52 for the half marathon in Valencia in 2021, a world record that still stands nearly five years later. Here is what running economy, altitude training, and pacing science say about how she did it, and the real difference between a mixed-race world record and a women-only best.
114 Pounds, Two Rings, One Rep: The Science of the World’s Heaviest Ring Muscle-Up
Roudy Kallas added 51.86 kilograms to a ring muscle-up, a Guinness World Record. Here is the real biomechanics and strength science behind how that is even possible, and how to train toward weighted calisthenics safely.
Too Tall to Sprint: The Physics Behind Bolt’s 9.58-Second World Record
Usain Bolt's 9.58 second 100m world record has stood since 2009, verified directly against World Athletics. Here is what sprint biomechanics research actually says about his height, stride length, and the ground force behind the fastest 100 meters ever run.
The Bar That Bends: Hafthor Bjornsson’s Elephant Bar Deadlift Record
In 2019, Hafthor Bjornsson pulled 474.5 kilograms on strongman's whippy elephant bar, a record separate from his famous 501-kilogram pull. Here's what actually happened, and whether it still stands.
5 Squat Alternatives: Match the Move to Your Goal
Compare backward sled drags, split squats, reverse lunges, hip thrusts, and wall sits by goal, range, and training tolerance.
Arnold Schwarzenegger’s Plant-Forward Diet: What Changed
Arnold Schwarzenegger says he eats far less meat than in his bodybuilding years. Here is what plant-forward means for health, protein, and strength.
Deep Resting Squat: Mobility Practice or Health Cure?
A deep resting squat can be useful mobility practice, but it is not a cure for posture, digestion, or back pain. Learn a supported progression.
Russel Orhii’s 338 kg Squat: The Record in Context
Russel Orhii squatted 338 kilograms at Sheffield 2025. See the class, equipment, judging, attempt strategy, and total behind the record.