Why Muscle Strength Matters and How Knee OA Trials Underdosed It

Three reasons are given to prioritize strength. For injury risk, the evidence is mostly indirect, but modeling in adolescent male footballers suggested that greater hip abductor and adductor strength was linked to about 10% fewer injuries. For pain, Muraki found that quadriceps strength relative to body mass was associated with knee pain in over 2,000 people with knee osteoarthritis, while grip strength and muscle mass were not. For mortality, a study by Li in over 4,000 older US adults linked low muscle strength to higher all-cause mortality, independent of muscle mass. The speaker then describes a 2017 systematic review that examined whether knee osteoarthritis exercise trials followed specificity, overload and progression. Every included study described its program as strength training, yet repetitions, sets, intensity and rest varied widely, and only one came close to a true strength protocol. This helps explain why earlier reviews could not show that strength training worked. Readers of older trials should check the dosing before accepting a negative conclusion.