Differences between stopwatch and fully automated timing

The differences between stopwatch and fully automated timing. In this post, we lay out the basic differences between the two methods.

While on-field success can be affected by an immense amount of variables at any time, an athlete’s physical performance test results also provide meaningful benchmarks and data in shaping their athletic future. 

Small differences in these performance numbers can translate to big differences in a career. The standard “combine” tests have become the gold standard for objectively evaluating and comparing individual athletic performance, and the annual NFL Scouting Combine is a vivid example of the importance athletic performance numbers are for teams and the general public. 

Athlete 40-yard dash times are a topic of discussion on countless TV programs, radio shows, and group text chains across America. For professional athletes, the 40-yard dash time is a performance number that can follow them for the remainder of their career.   

The two methods used in timing performance in the 40-yard dash are a stopwatch or a fully automated timing (FAT) system. These two different methods of timing will nearly always yield different times. 

Although it is generally acknowledged by professionals that hand-measured multi timer stopwatch are always “faster” than actual or electronic times, there have been few disciplined studies conducted to objectively quantify this difference.  

The purpose of this post (Part 1 of 2) is to address the first key questions: 

  • What are stopwatch timing and fully automated timing (FAT)?
  • Why do stopwatch and FAT yield different results for the same athlete?

WHAT are stopwatch timing and fully automated timing?

Stopwatch Timing 

With stopwatch timing, a online stop watch is used for measuring the 40-yard dash. The coach will typically stand at the 40-yard line. When the athlete leaves the starting line, the coach presses the stopwatch start button. When the athlete crosses the 40-yard line, the coach stops the time by pressing the same button.    

Fully Automated Timing (FAT) 

For fully automated timing (football-specific), a sensor is placed at the start line 1 inch above the ground and the 40-yard line at 30 inches from the ground. For the 40-yard dash test, the athlete will be in a 3-point stance with one hand on the start line thus blocking the start sensor. When the athlete’s hand is lifted as they begin running, the electronic timing system automatically starts. When the athlete passes through the finish (and ultimately the 40-yard sensor) this will automatically stop the timing system.

WHY do they yield different times? 

Simply put:   

  • Hand timing: the coach presses the start stopwatch button after the athlete starts to run. 
  • Fully Automated Timing: the time starts AS the athlete starts to run.   

Put another way, when using a stopwatch, the athlete will always have a ‘head start’ because the coach starts the time after the athlete starts to run.  Therefore, the time will always appear to be faster than a fully automated time.  

The average time it takes for a coach to press the start stop watch button after the athlete begins to run can also vary dramatically based on the human factors (e.g., coaches’ response time, general health, focus, vision, etc.) and even environmental factors (e.g., moisture, ambient light, etc.).