Final answer:
Counter-movement jumps are higher than squat jumps because they involve a pre-stretching of muscles and tendons, which stores kinetic energy. This stored energy is then released during the jump, resulting in a higher jump height.
Step-by-step explanation:
In counter-movement jumps, you first perform a downward movement by bending your knees and hips before explosively extending them to jump. This pre-stretch of the muscles and tendons stores kinetic energy, which is then released when you jump, resulting in a higher jump height. In squat jumps, you start from a stationary position with your knees and hips flexed and then extend them to jump.
While the squat jump also involves the same muscle groups as the counter-movement jump, the lack of pre-stretching reduces the amount of stored energy and, consequently, leads to a lower jump height. Therefore, counter-movement jumps are generally higher than squat jumps because they utilize the elastic properties of muscles and tendons to generate more explosive power.