This type of training aims to increase the amount of lean muscle in the body. It's especially useful for weight loss. It can also help with achieving a lean, toned look. For older adults, it can help counteract or reverse the age-related muscle loss that can lead to frailty. For novice and intermediate training, it involves doing 8 to 12 repetitions relatively slowly, generally for one to three sets per exercise. Rest periods of 1-2 or 2-3 minutes are advisable between sets, depending on the load.