On HIIT 100s sets during Weeks 1-3, when rest periods are 30 seconds or more, perform the first three sets of 10 as fast and explosively as possible. This will help build more muscle power and strength, despite using such light weight. On Sets 4-6, keep the movement slow and controlled, focusing on the contraction and squeezing each rep at the top for one to two seconds. This helps establish a strong mind-muscle connection, which is critical for muscle size, shape, and separation.
In a way, moderate-intensity physical activity is that "magic pill" a lot of people are looking for, because the health benefits go beyond keeping your waistline trim: Not only can it reduce your risk of cancer, stroke, diabetes and heart attacks, but studies have shown that physical activity can significantly improve the moods of patients with major depressive disorders.