Deeper squats produce greater thigh-muscle growth in controlled trials — Bloomquist's 12-week study found full squats outgrowing half squats — while knee-stress fears are not supported by studies of healthy joints.
HIIT improves VO2max faster per minute invested than moderate continuous cardio, a 2015 meta-analysis found, while steady state builds the same base with less strain — the choice hinges on time, joints, and enjoyment.
Progressive overload means systematically increasing the training stimulus over time, and decades of resistance-training research show the increases can come from weight, reps, or sets rather than one single lever.