Slowing down the lowering part of a lift (like slowly lowering a dumbbell) makes your muscles more damaged and triggers more repair and growth than quickly lowering it.

Resistance training is energetically inefficient in terms of total caloric expenditure due to predominant eccentric muscle actions and prolonged inter-set rest periods.

How fast or slow you lift and lower weights probably doesn’t make much difference in how much muscle you build—but it might matter a little depending on whether you’re pushing down, pulling up, working a specific body part, or going all the way to exhaustion.

How fast or slow you lift and lower weights probably doesn’t make much difference in how much muscle you build—unless there’s some special situation we haven’t figured out yet.

If you slow down the lowering part of weightlifting, your muscles might get more damaged and your body might release more of the hormones that help build muscle—this is what the claim says about guys who lift weights.

For women new to lifting weights, doing slow reps with longer muscle contractions builds more muscle strength and size faster than regular-speed lifting at the same effort level over 6 weeks.