Final answer:
We can jump higher during a countermovement jump because it allows for better muscle-tendon coordination and the storage and release of elastic energy, contributing to greater initial force.
Step-by-step explanation:
The reason we can jump higher with a countermovement jump is primarily due to better coordination between the muscles and tendons involved, which allows for a more effective use of elastic energy. A countermovement jump starts with a downward movement (eccentric contraction), which pre-stretches the muscles and tendons, storing elastic energy. When the direction is reversed for the actual jump (concentric contraction), the stored energy is released, adding to the force produced by the muscles, thereby creating greater initial force for the jump. In physics, it is similar to how a ball that is thrown downwards before bouncing up can reach a greater height.