The key is to keep constant tension on the muscles by maintaining a continuous cadence (no rest between reps) and reversing direction just short of lockout or just before bottoming out, depending on the exercise's strength curve.

Metabolic stress: Increasing time under tension (TUT) increases metabolic stressand gives you incredible pump, or muscle-cell swelling. This swelling cancause both an increase in muscle-protein synthesis and a decrease in proteinbreakdown, which are essential components of the process by which the bodyrepairs and grows muscle tissue after exercise (4,5,6)