If you train by lowering weights slowly (eccentric), you’ll get stronger at lowering weights; if you train by lifting weights up (concentric), you’ll get stronger at lifting them up — and this happens no matter how sore your muscles get.

You can get just as strong by pushing weights up as by lowering them slowly—even if lowering them doesn’t make your muscles sore or damaged.

If you train by lowering weights slowly, you get stronger at lowering them—not at pushing them up—and vice versa, even if you do the same total amount of work.

Lifting weights slowly (eccentric) or quickly (concentric) both make your quads stronger in about 10 weeks — and you don’t need to be sore or damaged to get stronger.

Most of the strength gain in the untrained arm happens in the first month of training—after that, it plateaus, showing that the brain and nerves adapt quickly, not the muscles.

If you're new to lifting weights, doing a moderate amount of workouts each week will make you stronger faster than doing very few workouts — and you'll keep getting stronger week after week for the first 9 weeks.