Which of the following is NOT a type of timing system used in sprint timing?

• A. Single beam
• B. Dual beam
• C. Signal processing system
• D. Smartphone app

Answer: (D)

Sprint timing relies on precise, dedicated hardware that detects when a runner interacts with a sensor and converts that moment into an exact time. Classic finish-line setups use sensors like single beam or dual beam infrared systems to mark the finish, providing clean, repeatable start/finish readings. The signal processing system handles the raw sensor data, applying calibration and producing the final times that officials publish. A smartphone app, while handy for informal timing, cannot guarantee the level of precision, calibration, and reliability official results require. Smartphone timing suffers from variable latency, inconsistent triggering, and limited resolution, making it unsuitable for official sprint results.