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Posted: 2024-06-07 06:49:15 (CT)    [ 307 views ]


Many of you know; I am not a scientist, engineer, researcher, mathematician, or doctor, but I am an experienced baseball player who also played football and basketball as my three primary sports in my younger days.  However, I was always curious about why it took me so long to adjust to outside shooting in basketball—even daily in practice—and especially on road trips. I played sports in the mountainous four-corners area of Colorado, New Mexico, Arizona and Utah where every road trip took us into a different elevation, but I had no knowledge of barometric pressure’s impact.  So, these days I understand more about elevation and its associated barometric pressure, and I am still curious if there might be more to learn.  Oh--and maybe I should mention that my degrees are in coaching with an emphasis on kinesiology, and business education. 

Cold Fronts and Warm Highs

A well-known subject in the medical world is the impact that weather patterns have on body parts.  This is particularly impactful on joints such as knees, shoulders, hips, and areas where past injuries have occurred.

Weather patterns are associated with barometric pressure changes.  A low-pressure atmosphere is typical when a storm is approaching at any elevation.  These low-pressure systems bring down the atmospheric pressure from the actual local pressure by as much as .70 inches of mercury on the barometric scale.  A high-pressure system causes the local pressure to increase by a similar amount, but both high and low systems can fluctuate between .01 inches change and .70 inches change of mercury on the barometer and, daily.   

I am certain that the scientific scale was intentionally formulated to approximate 1 inch of mercury to equal 1,000 feet of elevation, so .50 inches (1/2”) of mercury change due to weather approximates 500 feet of elevation change.  Can .50 inches of mercury change in air pressure be more significant than it appears due to an approaching weather system either high or low?

Those individuals whose knees and other joints begin to feel pain with a relatively quick weather low-pressure change, may not feel it in the body if they travel upward in altitude by only 500 feet in a vehicle, probably due to the time it takes to drive it.  

My wife has had some neurological damage due to the “Chicken Pox” virus having caused a bout called Ramsay-Hunt.  Barometric pressure changes of .01 to .03 inches of mercury lower than the normal local pressure (which sounds extremely minor to the public) causes headaches to occur whether during sleep or awake.  This has been going on with her for about two years.  It is the same condition that star singer, Justin Bieber has experienced over a similar period although with differing symptoms.  

Another acquaintance of mine has confirmed that he has experienced the same effects of headaches occurring with low pressure systems.  His neurologist has acknowledged that this is common.  Low pressure systems in the atmosphere cause high pressures inside the body, such as brain, intestine, joints, bones, and bladder to mention a few well-known body parts.   Conversely, high-pressure systems in the atmosphere cause lower pressures inside the body and therefore tend to relieve some of those same symptoms.  There have been some studies done by Japanese researchers in this arena and confirm that migraines and other headaches can be triggered by low pressure systems.

The public--including athletes--see reports on television about weather and the barometer reads 29.92 inches of mercury.  Then, with a periodic low pressure system the report changes that standard barometric pressure reading to 29.90 inches and they conclude--almost nothing, right?

The Weight of a Baseball Added to a Basketball?

What would you think if you discovered that a storm system air-pressure change like this could require a basketball shooter to push the ball hard enough with additional thrust to off-set the extra weight of high pressure, or shoot more softly to off-set a low, as if an MLB baseball were added to, or subtracted from the weight of that basketball?

Air pressure changes constantly.  Not only with major pressure systems, but fluctuations are normal and tides in the ocean may affect air pressure systems on planet earth, as well.  But modern research seems to indicate the small hourly changes are more about the heating and cooling cycles of the earth in the more local area.  

In the United States, mathematics regarding barometric pressure have been calculated using a scientific scale that is meaningful to scientists, however the scale was not intended for sports, but for weather predictions.  So, the question now, is—what is the actual physical impact of air-pressure that has already been defined by scientists, but on a scale that makes it appear very minute to the non-scientific populus?  How do we interpret a .01’s effect on a large light-weight ball traveling through the air at a relatively slow speed, such as a launch by a human being at a basketball ring using legs, shoulder, elbow, wrist, and fingers to do so?

Let’s look at the same air pressure amounts that affect joints, etc. in the body, while asking the question; how may that affect an athletic event?  

In baseball, the air pressure is responsible for late movement on pitches and distance of ball flight on hits.  In football it affects the distance of both passes and kicks.  In soccer it affects the distance and curvature of longer kicks and the corner kick.  In basketball it affects the shooting distance and the tightness of the bouncing ball.  In tennis it affects the speed of the hit and the curvature of both serves and returns, primarily because of the tightness of the ball, but also the amount of downward curvature required to keep the ball in the court at high speeds. All present-day sports have long ago considered the tightness of the ball when changing altitudes and have made regulations surrounding this aspect of athletic events.  (see “deflate gate”)

However, as far as we know, it is impossible to regulate the hourly and minutely fluctuations of pressure within inflated sport balls, such as basketball, soccer, tennis, and volleyball, to name a few.   We can limit this discussion to basketball and soccer, because tennis balls are too small to be affected to a high degree by the small fluctuations of plus or minus .01 to .05 inches of mercury.  But how this may affect sports is still unknown, because of the length of games and other issues.

Volleyball also needs to be a non-consideration in this discussion due to the size of the court.  So, basketball and soccer have both larger courts/fields and larger internal air space within them.  Soccer does have a goal and corner kicks are highly affected by field elevation in terms of the visiting team being less familiar with the curvature of the kick. However, the goals in soccer are larger than the hoop in basketball; therefore we can assume the soccer game is affected to a lesser degree than is basketball.

So, the basketball three-point shot at a small target is probably the most affected by the small fluctuations of plus or minus .01 to .05 inches (absolute) of mercury.  This continual air pressure fluctuation may be one of the causes of inconsistent shooting for an entire team.  Also, shooting can be inconsistent for only certain periods in a game of basketball.  In other words, periods of hot or cold team shooting.  These well-known aspects of basketball may be somewhat explainable if the air-pressure causes more than a 1-inch differential in flight distance.  We already know that confidence is a factor in shooting, so that portion of inaccuracy is as well documented as is possible.  Air-pressure hour-by-hour changes are not documented in sports competition; therefore, we will attempt to look more closely at this subject.

Physics laws are well established that barometric pressure, temperature, and humidity does change the density of the air.  The density in turn affects both the flight of the object due to forces against the exterior surface of the ball, and the interior spacing of air within the ball.  Both aspects of air density effects are well documented.  But how much could the change in pressure free the ball in flight or hold it back?

Standard Barometric Pressure

Some of the general population’s misunderstanding of air pressure stems from the “Standard Barometric Pressure” vs the “Actual Barometric Pressure”.  Standard pressure is stated as 29.92 inches of mercury at every location and therefore the hourly fluctuations range from approximately 29.401234 inches during low pressure conditions to approximately 30.51234 inches in high pressure conditions.  The difference from the low to the high is a range of approximately 1.11106 inches of mercury, but normally not on the same day and only in one direction (either up or down) during an oncoming storm or a fair-weather high.  All the daily fluctuations would not normally occur during a 2 to 3-hour game. 

During a game, pressure changes would tend to be less than .5 or ½ inch movement on the scale, but at .025 to .035 on the scale "either direction" happens during every basketball game.  So, the question becomes—does 0.025 inches to 0.035 inches of mercury on the scale represent forces substantial enough to influence the distance of the three-point shot in basketball?  So, let’s dig in. 


Actual Barometric Pressure

Molecules of air have weight just like anything else. Actual barometric pressure depends on the altitude of the location because pressure is caused by all the molecules of air pressing down by gravity on the molecules below between the earth’s surface and the outer atmosphere.  So, at altitude, there are fewer molecules above to weigh down on the air below. But, during this discussion, let's also keep in mind that air pressure is not only downward, but upward and side-to-side, as well. 

Sea Level Air Pressure  =  14.7psi
Denver Actual Pressure = 12.3psi
Difference in Actual psi =    2.4psi

My research and data collection in the sports of both baseball and basketball have verified beyond any doubt that air density affects the success of the players of all teams in a similar way with only one exception.  That exception is when a ‘home team’ plays half of their schedule in a unique light air (due to altitude) sports venue, then traveling to more standard venues creates a disadvantage in baseball hitting and basketball outside shooting adjustments until more exposure to the norm is complete.  (See Colorado Rockies baseball and Denver Nuggets basketball, University basketball and baseball in Utah, New Mexico, Texas, Wyoming, Nevada, Virginia, Washington, Georgia, and Arizona plus a few others)

Conversely, when a “visiting basketball team” travels into a uniquely light air location it is generally for only 1 game before returning to more normal environments.  Therefore, while good teams regularly lose games in unique environments, it has less impact on their overall record than the impact on home teams.  

The research has identified more than simply the advantages of certain densities of air in baseball and basketball, but also the performance issues that are presented to participants when changing locations and therefore atmospheric conditions.  

In baseball the data clearly shows the impact on hitters’ success during road trips given the atmospheric conditions of the day and reveals when pitcher advantage ebbs and flows against hitters in both home and road games.  Hot air, high altitude or high humidity favors the hitter and cold air, low altitude or low humidity favors the pitcher.  But basketball is quite different.

In basketball, the data shows that 3-point shooting for all teams is affected by air density changes due to altitude, temperature, and humidity levels when teams change locations.  What we do not know yet is how much do small hourly changes in air pressure affect the sport of basketball even at the players’ home venue.

Difference in Thrust from Denver to Sea Level for Basketball 3-Point Shooters

We do know this much: the difference between sea-level pressure (14.7psi) and Denver, Colorado’s altitude being over 5,200 feet in elevation (12.3psi), creates an air pressure differential of approximately 2.4 pounds per square inch (psi).  If the front portion (leading nose) of the basketball that is most affected by the push-back of air molecules is a circle about 6 inches diameter, then the most direct air pressure is against a circumference area that contains about 28.27 square inches. 

Using that minimal representation of an imagined heavily effected area of the basketball--in transition from Denver--a men’s basketball player must force the ball to fly to its peak with a thrust of an additional 2.4 psi X 28.27 sq. in.  which equals 67.848 pounds or rounded to 68 pounds.  However, since air molecules are pressed together by the weight of all the air surrounding the earth, when an object such as a basketball is launched, the air molecules that are forced around the ball, “snap” back together behind the ball thereby somewhat helping to push the ball in its flight.  

Push-Back by the Air

I am purposely using common language to describe the actions of the air, because physics and aeronautical terminology can be confusing to those individuals not educated in those disciplines.  Since air molecules are pushed together by the weight of other air, but vigorously repel each other to maintain the same distance between, then additional pressure is created by those molecules being forced together or pulled apart.  This is what causes the air to “push-back” when an object is launched through it. The force of air is huge, allowing airplanes to fly and causing tornados and hurricanes and high winds.  So, small changes in the air have an effect, but what we want to know is—how much by the smaller changes?

Sea Level vs Denver



So, if every action creates an equal and opposite reaction, then we can assume that the approximate 68 pounds of thrust by a shooter becomes an estimated 34 pounds of thrust to shoot the same distance at sea level vs Denver, Colorado where say the Denver Nuggets are more familiar with shooting.  Since the air flows around all the perimeter of the basketball, there is less pressure outside the 6-inch circle I defined as the “nose” of the basketball with the most direct pressure against it.  I have not considered the more perimeter area pressure, because that portion may be offset totally by the forces of the air on the back side of the ball that are well documented.

Difference in thrust from Denver to Sea Level for Basketball 3-Point Shooters
Sea Level Elev =  .49131 lbs/inch thrust
Basketball nose = 28.27 sq. inches
Thrust required = half of 68 pounds or 34 lbs

Sea Level Without Changing Locations

So, with that in mind, let’s look at how the numbers identify the potential thrust differentials caused by what we think of as small air pressure changes that occur “during” all basketball games without changing elevations.  These daily ups and downs of the barometric pressure will affect the home team as well as the visiting team, if the thrust differential is large enough in actuality to affect the flight.

Sea level air pressure of 29.92 inches of mercury equals the 14.7psi 

(or .49131psi per inch of mercury)

So, to consider what smaller changes in pressure might cause in performance, we must calculate both the amount of pressure and the amount of thrust to a smaller and smaller degree.  To look closely at the practical application of seemingly small pressure differences, it is better not to round the decimals, but to present the actual numbers.  So, from this point forward, the numbers will not be rounded below four decimals until we arrive at those minute numbers.

At sea level ½ inch (.5 in) of mercury change--or 500 ft. elevation-- equals half of the above calculation of a full inch, or .24566 psi times the nose of the basketball (28.27 sq. inches) = 8.3336 pounds of thrust differential from normal--required to shoot the basketball the same distance in the same sea level arena.  Therefore, half that amount of pressure change would be .25 in of mercury or ¼ inch, and that would equal 4.1668 pounds of thrust difference needed by the player.  

At The Same Home Arena at Sea Level
.5 (1/2 in.) pressure = 8.3336 lbs extra thrust
.25(1/4 in.) pressure = 4.1668 lbs extra thrust

In basketball, the amount of flight differentials over the three-point distance still needs to be verified, but the existence of needed distance adjustment by players is fully verified.  However, these small hour-by-hour changes in exterior (to the basketball) air-pressure still need to be studied in more depth. So, let’s take it to the most minute of numbers.

Converting From Pounds to Ounces of Weight

We have calculated the scientific scale of air pressure from 14.7psi (one atmosphere) down to .25 inches of mercury on the barometric scale or ¼ inch.  But on an hourly basis, during an NBA or College basketball game, pressure normally changes by only .01 to .03 inches of mercury. So, to get to the smaller scale, it would be best to convert to a smaller than pounds weight scale which in the U.S. is ounces.  When 4.1668 pounds is converted to ounces by multiplying by 16 ounces per pound it calculates to 66.6688 ounces.  Therefore, one tenth of a quarter inch being .025 is 6.6668 ounces, or very near the weight of an MLB baseball.  The identified minimum pressure change of .01 inches of mercury is 2 and ½ times smaller than .025 and calculates to 2.6667 ounces of pressure differential, and .03 inches of mercury (the identified maximum probable change during a game) is three times larger than .01 inches of mercury which calculates to 8.0003 ounces of pressure.  

At The Same Home Arena at Sea Level
        —Convert pounds to ounces—
4.1668 pounds x 16 ounces = 66.6688 ounces
.025 inches pressure = 6.6668 oz. extra thrust
Or a little more than the weight of an MLB baseball.

So, we have it narrowed to typical hourly changes in barometric pressure either up or down will cause the shooter to “unknowingly” either begin trying to take off or add some thrust to the shot to make the shot fly the same distance as before the barometric pressure changed.   

The calculation of .01 inches of mercury to .03 inches of mercury pressure changes, will cause between (rounded) 2.7 ounces of thrust and 8.0 ounces to be either taken off the shot or added to the shot to complete the player’s adjustment, depending on whether the pressure change is up or down.

So, in conclusion—and now I can round the numbers—every change in barometric pressure by the amount of .01 inches of mercury causes 2.7 ounces of thrust adjustment either lesser or greater by the shooter to shoot the same distance as he/she was shooting prior to the common and continual barometric pressure changes.  If the barometric pressure changes by .03 inches during a game requiring 8 ounces of additional thrust, then that is more than the weight of the 5.5 oz MLB baseball for which the basketball shooter must account.  

At The Same Home Arena at Sea Level

Here are game time possibilities:

.01 in of mercury causes 2.7 oz thrust

.03 in of mercury causes 8.0 oz thrust


Could this be part of the cause of periodic cold shooting in College and Professional Men’s and Women’s basketball?  The complication in this is what I am trying to point out.  It is a fine adjustment, but a necessary adjustment to make.  How does one take off between 3 and 8 ounces of thrust to make the basketball fly the same as it did earlier in the game?  Well, it takes a few shots to realize an adjustment needs to be made, and then get back on track, only to have the pressure change again during the next ½ hour or so within the game.  

Studies in Barometric Pressure Hourly Variations

A study by a US-Japan team of scientists headed by Manoa Professor Kevin Hamilton at the International Pacific Research Center have determined that variations in daily barometric pressure occur differently in certain places around the U.S.  Also, that variations are milder in certain seasons than in others, especially in summer vs winter.  Basketball, being a winter sport, may have a greater spread in daily barometric pressure variations.  And that spread of variations may be greater in some cities.


Basketball Overall Weights and Sizes Professional Men’s and Women's

NBA – 22 ounces and 29.5 inches circumference, diameter 9.5 inches

WNBA basketball  - 18 ounces  and  28.5 inches circumference, diameter 9.2 inches

So, wait! We are not done with this topic! What if the 6 inches most affected area of the 9.5-inch men’s basketball diameter is larger than that?  What if I use “7 inches diameter” of the basketball as the “most directly affected area”?  Here are those numbers. If the front portion (leading nose) of the basketball that is most affected by the push-back of air molecules is a circle about 7 inches diameter, then the most direct air pressure is against an area that contains about 32.98 square inches.  

So, the minimum pressure change of .01 inches of mercury is 2 and ½ times smaller than .025 and calculates to 3.1 ounces of thrust differential, and .03 inches of mercury is three times larger than .01 inches of mercury which calculates to 9.3 ounces of thrust to be either taken off the shot or added to the shot to complete the players adjustment.  The latter amount of thrust is almost double the weight of an MLB baseball.

At The Same Home Arena at Sea Level & 7" Most Affected Area:

“Air Pressure Change Requires Thrust to Change”
.01 in of mercury causes 3.1 oz thrust
.03 in of mercury causes 9.3 oz thrust

Why am I doing this, you may ask! 

What can be done to alleviate the issue if it exists at the levels I am calculating?  

I do have some ideas of how this could be helpful for a college basketball team or a professional team, but that is probably a subject for another time.  However, knowledge is power, and someday, someone who is a coach or a technician or scientist or a coaching assistant, may be able to come up with something that can help far more than I am able.  

I am presenting the question because no one else has.  Does this need to be studied? Yes!  If you have knowledge in this arena of mathematics, physics, weather, basketball or aeronautics and can correct any of my logic or math, please contact me!  I would like to learn as much as is possible about this subject. 


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