Truth revealed on art, science of 40-yard times

—By Michael Weinstein, Special for—

(Editor’s note: Weinstein has an MBA in Mechanical Engineering and is the founder of Zybek Sports, which has handled Indy Combine timing since 2008)

An athlete’s physical performance test results provide an important specification that often determines their future. Small differences in these performance numbers can make big differences in their career.

The standard Combine tests are the gold standard for objectively evaluating and comparing individual athletic performance. The annual NFL Scouting Combine is a vivid example of the importance athletic performance numbers are for teams and the general public. Since 2013 the NFL Scouting combine at Indianapolis generated more than 8 million viewers a year.

An athlete’s vertical jump and 40-yard dash times are discussion topics on countless TV programs, radio shows and water-cooler banter across America. And these times are talked about to the hundredth of a second.

The current record for a 40-yard time at the Indy Combine is 4.22 seconds, set by Washington wide receiver John Ross last year. Although it is seldom asked, that time was started by hand and stopped when he crossed a laser beam. At most pro days and other events, the clock is started and stopped by hand.

Yet conversations about the results — again to a hundredth of a second — rarely differentiate which timing method was used. My studies show this is a major oversight.

So I set out to provide an objective analysis that quantifies the differences between a hand-timed and fully automated timed 40 yard dash.

Hand Timing versus Fully Automated electronic timing:

Hand Timing:

Historically, coaches used a hand-held stopwatch for measuring the 40-yard dash. Typically, the timing coach will stand at the 40-yard line. When the athlete leaves the starting line, the coach depresses the stop watch start button. When the athlete crosses the 40-yard line, the coach stops the time by depressing the same button. The time displayed on the stopwatch then becomes the athlete’s 40-yard dash time.

Fully Automated Timing (FAT):

Several different Fully Automated Timing methodologies are used in the industry whereby the actions of the athlete will start the time and stop the time. To stop the timer, an electronic sensor which is viewing a special, non-visible light is often used. When the athlete’s body blocks the light, the sensor sends a signal to the timing unit to signify an athlete has run past the line. This can happen in less than 0.0001 seconds. These are typically referred to as “laser” sensors. Several different options are available to determine
when the athlete starts the run, including:

–Pressure pad at the start line. A signal is provided to the timing unit to start the time when the pressure on the pad has been removed.

–Positioning a “laser” sensor in front of the athlete. When the light in this sensor is interrupted by the athlete’s body, the time starts.

–Positioning a “laser” sensor at the start line. A signal is provided to the electronic timing system
when the laser is not blocked.

The time result of a FAT 40-yard will almost always be greater than a hand-timed 40-yard run, meaning the same person will have a “slower” 40-yard dash result if timed using a fully automated system than a hand-timed 40-yard dash.

The majority of the time difference between the FAT and hand-timed 40 comes from the inherent human delay of starting the timer after the athlete initiates the run. So, the athlete will have started the run before the coach depresses the start button. Therefore, the hand-timed numbers always appear to be faster than electronic times. Compounding the inherent variability of the hand-started times are differences in athletes, coaches, time of day, weather conditions, etc.

Although it is generally acknowledged by professionals that hand measured times are always faster than actual or electronic times, there have been very few disciplined studies conducted to objectively quantify this difference. One possible reason that an objective study has not been completed is the large number of variables that can have a significant effect on the results. These include: human factors (e.g., coach’s response time, general health, focus, vision, etc.), environmental factors (e.g., moisture, ambient light,
etc.) and the type of FAT system used for the comparison (primarily start method).

My study was designed to answer the following question:

What is the difference between hand times and FAT times under the best possible testing conditions?

Although the statement: “best possible testing conditions” is inherently subjective, significant efforts were made to select a 40-yard test being conducted by a very reputable and experienced combine testing organization with defined procedures; with a highly-trained and highly regarded coach, and under ideal weather conditions. Furthermore, the FAT system used to measure the electronic time was the same equipment and process used in combines in this study since 2011.

NFL Scouting Combine. Although the other timing FAT start methods listed above are viable, the position start was selected because it is has been used at the NFL Scouting combine and anything different could bias the data. Also, the FAT electronics provided by Zybek Sports are tested and fully traceable to the Atomic Clock located at the National Institute of Standards and Technology located in Boulder, Colorado.

A veteran coach (17 years of experience as of 2018) who represents an established athlete testing company was selected to establish the best possible baseline data set to quantify the difference and variability between hand and electronic timing. Arizona under ideal weather conditions.

Test Procedure and Setup:

Extreme care was taken to not introduce any new variables for the combine event that could bias the data. To that end, Zybek Sports provided five independent timers that were started at the exact same time by the position-start system used for standardized combine testing.

Data Collection and Testing Process:

There were no changes to a standard combine and testing process for this test. Athletes were instructed to run the 40-yard dash, starting from a 3-point stance as done at the NFL Scouting Combines. Each athlete ran the 40-yard dash twice. The only difference in this combine was that the coach was provided a standard stop watch that had a wire connected to it. This wire was connected to one of the Zybek Sports timers.

Zybek Sports provided five fully automated timing systems. All five of the timing systems were started when the athlete’s hand was lifted from the start line upon the start of the run. By using the position start sensor, the athlete initiates the time automatically without requiring any difference in the start technique.

To measure the difference between the hand time and the electronic time, a signal wire was used to connect the stopwatch to electronic timer. The timer was started when the athlete left the start line and stopped when the coach at the 40-yard line depressed the start button. This method accurately measures the difference in the coach-started time and the fully automated start time without introducing additional variables.

Hand Time v. FAT Time Data


The timer that measured the difference in the hand time to the FAT time was started when the athlete lifted his hand and stopped when the coach at the 40-yard line depressed the start button on the stop watch. These times were recorded for all athletes on both 40-yard runs.

The measured differences between the hand-held and the FAT timer ranged from 0.10 seconds to 0.25 seconds. The time differences were evenly distributed between 0.10 and 0.25 seconds, with the average being 0.175 seconds.

So, based on this experiment data (and only accounting for human error at the start not the finish line), the average hand-timed 40-yard run is 0.175 plus .075 seconds “faster” than a fully electronic time. Here are some recent examples:

**Player School NFL Combine Pro Day Time Difference**

Xavien Howard Baylor 4.6 4.38 0.22

Deion Jones LSU 4.59 4.38 0.21

Braxton Miller Ohio State 4.51 4.33 0.18

Shawn Oakman Baylor 4.96 4.78 0.18

Michael Thomas Ohio State 4.57 4.4 0.17

Joey Bosa Ohio State 4.87 4.7 0.17

Andew Billings Baylor 5.06 4.92 0.14

Jalen Mills LSU 4.62 4.48 0.14

Based on consistency over years, we believe this data can be considered a valid representation of the minimum error that occurs when using hand timing for the 40-yard dash at scouting combines, and under ideal situations with experienced personnel.

Although a .175 + 0.75 error can appear inconsequential, in a sport such as football 1.1 million athletes are competing for 69,600 collegiate spots, thus making performance-testing data critical in determining an athlete’s future.

For such a hypercompetitive field such as football the difference between a 5.0-second and 4.8-second 40 for the 40-yard dash can significantly alter an athlete’s trajectory. Additionally, to continue providing NCAA colleges with the best prospective athletes, a 0.175 second error for the 40-yard dash is evidence enough to encourage standardization in Scouting Combines.


There are 6.9 million high school athletes in the United States competing for 450,000 college positions. Presenting accurate and consistent data from standardized combine testing is an increasingly important as the number of competitors continues to grow and as modern training methods are expanding the bounds of athletic potential.

The error from hand timing results in a minimum of 0.1 to 0.25 second difference from electronic timing. The 1.75 + 0.075 second variance should be considered if hand timing is being used for ranking athletes. Finally, accurate and repeatable testing data provides a training metric that can be used for improving the combine scores.

So the next time somebody cites a timing of, say, 4.32 seconds for a 40-yard dash, ask what method was used. If it was a hand-held time, it might have been comparable to, say, a 4.49 at an Indy Combine.


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