Final answer:
Speed and agility tests should typically be 10 seconds or less to accurately measure these specific attributes without undue influence from the athlete's endurance.
Step-by-step explanation:
The recommended length for tests of speed and agility is generally 10 seconds or less.
Such brief durations help ensure that the exercises are focused on measuring true speed and agility, as performance in these tests can be significantly influenced by the athlete’s anaerobic capacity which is best assessed over short, intense efforts.
Lengthier tests may begin to assess other attributes like endurance rather than just speed and agility.