Objective: To compare the immediate. short term and long term effects of active isolated stretch versus post isometric relaxation on hamstring flexibility in young healthy adults. Study Design: Randomized controlled trial (trail number is NCT04024839). Place and Duration of Study: Islamabad Federal College. https://www.bekindtopets.com/save-now-Aqua-Pure-3MFF101-Full-Flow-Drinking-Water-System-Replacement-Cartridge-flash-choice/