Strength
Strength refers to the ability of muscles to generate force against resistance.
Building strength leads to increased muscle mass, endurance, and overall physical capability.
The long-term benefits also include increased bone density (and lower risk of osteoporosis), lower risk of cardiovascular disease, enhanced mental health, increased sleep quality, and higher levels of energy.
Strength is built by working close to your limit and raising the difficulty gradually: more reps, more sets, a harder variation or more weight. Muscles get stronger while they recover, so rest between sessions is part of the training.
It is one of the 4 components of a comprehensive physical development.