Historical Height and Weight Analysis of Male Athletes in Professional SportsNicholas Inman and L. Wayne Hamlin

National Science Foundation: Research Experience for Teachers2013 Summer Program at Appalachian State University

Abstract- The purpose of this study was to analyze the changes in height (inches) and weight (pounds) of the male athletes in the National Basketball Association (NBA) (1902-1991), Major League Baseball (MLB) (1835-1992), National Football League (NFL) (1876-1990), National Hockey League (NHL) (1873-1994), and US Summer Olympians (Height: 1840-1992, Weight: 1864-1992).[1] Data mining was used in the collection of mass amounts of athlete information. Statistical analysis was used to analyze the collected information and to study the changing height and weight of the average US male against the athletes studied.

I. INTRODUCTIONThe appeal of modern professional and Olympic

sports among men has produced a greater number of athletes compared to their predecessors over the past one hundred years. Changing physical attributes of height and weight among male athletes in baseball, basketball, football, hockey and the US summer Olympic program may be attributed to the increased availability of food, health, nutrition, and supplements. Increased metabolism and muscle development in male athletes by advanced techniques in exercise physiology may have further increased the height and weight of modern athletes. Selection of male athletes who are stronger, faster, more powerful and skillful, with the ability to quickly adapt to changes in game play has narrowed the available population of athletes to a select few each year.  Competition between athletes requires substantial time and effort to acquire the skills and physical constitution necessary for a successful career as a professional or Olympic, male athlete. [3,4]

Overall body type, specifically height and weight have traditionally been indicators of health and physical ability across most cultures and especially in the US.  While male athletes in the late 1800’s and early 1900’s were generally smaller in stature, fewer men could afford to participate in sports and less money was available for the formation and continued support of athletic teams.  As the industrial revolution impacted America in the 19th century, urbanization concentrated large populations. [4] With two world wars and a US military that taught boxing as hand to hand combat, public gyms and athletic centers like YMCA’s became more available in the cities. Male athletes could begin to concentrate on specific sports, specific muscle groups and thus, specific trainings. The introduction of the National Public Education would further introduce and foster fitness and sports

to young men at an earlier age with gyms available as part of the school and athletic competitions between schools. While participation for physical education was mandatory for all young men in school, then, as today, students whose height and weight would be best for a team winning would be selected.  In time, athletic prowess would also open available slots to university students through scholarships. A further concentration of the most appropriate height and weight male athletes would focus sports at both a collegiate and professional level of competition.  In a short time, college and professional athletes would generate many athletes wishing to follow in their footsteps. This elicited greater competition among younger athletes and a well-defined pool of athletes for coaches and trainers to select the best for competition, with height and weight providing an initial test in the selection of athletes. [1,3]

The purpose of this study was to analyze the changes in height and weight of male athletes in NBA, MLB, NFL, NHL, and the Summer Olympics over the last century.  The initial hypothesis for the study is that there is no change in the height or weight of athletes each year, with the alternate hypothesis being that there is a change.

II. METHODOLOGYFinding an appropriate internet database was

essential for data mining. Upon finding a database that provided the name, height, weight and birthdate of each athlete in the selected sport, mining was required to quickly and accurately gather then store the data. Using the add-on to Mozilla Firefox, DownloadThemAll! 2.0.16, the website containing each player’s information was saved from the database to a hard drive.

Certain markers were discovered in the HTML code for each database that allowed for the gathering of information from every player page. Using Active Perl, code was written that opened each saved website and then converted the HTML page into a plain text file. Next, the program would search inside the resulting text file for a keyword, such as “Height”. Upon finding this keyword Active Perl would export certain formatted characters immediately after the keyword into a CSV file. The player data from each sport was refined using Microsoft Excel. It was common for some athletes to have missing data. Only if a birth year was missing would the data be completely removed. This process is shown in Flow Chart 1.

Each sport utilized a separate database with different webpage formatting; therefore, each

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Flow Chart 1: Data Mining Process Flow Chart 2: Data Analysis Process

database required a new version of the Active Perl program. Only certain aspects of a player’s profile were required for this research. The program would separate the feet and inches from a height to export the total height in inches, and the birth year from a date to simplify the research goals. Variables recorded from each sport were name, total height (inches), weight (pounds), and birth year.  The historical measures of inches and pounds are still used in American sports today.

For statistical analysis, data was separated by sport and by birth year. Any player without a known birth year was removed from the study.  The height

and weight of players was then averaged according to birth year. Microsoft Excel was used to create scatterplots, compute linear regression, and perform t-tests as shown in Flow Chart 2. T-tests were conducted for height and weight per sport against the birth year to test the significance of the regression slope. The t-value was calculated by dividing the regression slope by the standard error of the slope. Also the data per sport was averaged per decade and compared against known height and weight averages of American males per decade. A one-sample t-test with a 1% significance level was used to determine whether decade averages were significant.

III. ANALYSIS

National Basketball Association (NBA)

Figure 1: National Basketball Association; [8]Average Height vs. Birth Year 1902 – 1991.

Slope: 0.07422338 inches per year3892 basketball players, r2 = .7949

T-Value = 17.68, df = 78

1895 1915 1935 1955 1975 1995160

170

180

190

200

210

220

230

240

Birth Year

Wei

ght (

lbs)

Figure 2: National Basketball Association; [8]Average Weight vs. Birth Year 1902 – 1991.

Slope: 0.49319769 pounds per year3892 basketball players, r2 = .832,

T-Value = 19.65, df = 78

Major League Baseball (MLB)

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1895 1915 1935 1955 1975 199566

68

70

72

74

76

78

80

Birth Year

Heig

ht (I

nche

s)

Figure 3: Major League Baseball: [6,7]Average Height vs. Birth Year 1835 – 1992

Slope: 0.036764 inches per year17878 baseball players, r2 = .951,

T-Value = 54.490, df = 153

1830 1870 1910 1950 1990140

150

160

170

180

190

200

210

220

Birth Year

Wei

ght (

lbs)

Figure 4: Major League Baseball: [6,7]Average Weight vs. Birth Year 1835 – 1992

Slope: 0.2781 pounds per year17878 baseball players, r2 = .870,

T-Value = 32.0, df = 153

National Football League (NFL)

Figure 5: National Football League: [11]Average Height vs. Birth Year 1876 – 1990

Slope: 0.0351 inches per year22893 football players, r2 = .680,

T-Value = 15.16, df = 108

1870 1900 1930 1960 1990170

180

190

200

210

220

230

240

250

260

Birth Year

Wei

ght (

lbs)

Figure 6: National Football League: [11]Average Weight vs. Birth Year 1876 – 1990

Slope: 0.500214 pounds per year22893 football players, r2 = .832,

T-Value = 23.13, df = 108

National Hockey League (NHL)

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1830 1870 1910 1950 199062

64

66

68

70

72

74

76

Birth Year

Heig

ht (I

nche

s)

1870 1900 1930 1960 199064

66

68

70

72

74

76

Birth Year

Heig

ht (I

nche

s)

Figure 7: National Hockey League: [12]Average Height vs. Birth Year 1873 – 1994

Slope: 0.041491 inches per year7351 hockey players, r2 = .838,

T-Value = 24.75, df = 118

1870 1895 1920 1945 1970 1995140

150

160

170

180

190

200

210

Birth Year

Wei

ght (

lbs)

Figure 8: National Hockey League: [12]Average Height vs. Birth Year 1873 – 1994

Slope: 0.33878382 pounds per year7351 hockey players, r2 = .802,

T-Value = 21.82, df = 118

US Summer Olympics

Figure 9: US Men’s Summer Olympians: [13]Average Height vs. Birth Year 1840 – 1992

Slope: 0.027234 inches per year3268 Olympian athletes, r2 = .464,

T-Value = 10.64, df = 131

1860 1880 1900 1920 1940 1960 1980 2000130140150160170180190200210220230

Birth Year

Wei

ght (

lbs)

Figure 10: US Men’s Summer Olympians: [13]Average Weight vs. Birth 1840 – 1992

Slope: 0.141509 pounds per year3105 Olympian athletes, r2 = .1896,

T-Value = 5.32, df = 121

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1870 1895 1920 1945 1970 199562

64

66

68

70

72

74

76

Birth Year

Heig

ht (I

nche

s)

1840 1860 1880 1900 1920 1940 1960 1980 2000606264666870727476

Birth Year

Heig

ht (I

nche

s)

Table 1: Player Height Slope Validity and 95% Confidence Interval.Each Recorded P-Value < 0.001

Sport Slope Standard Error T-value DF 95% CI of Slope

Lower UpperNBA 0.074 0.0048 17.38 78 0.063 0.082MLB 0.036 0.0006 54.50 153 0.035 0.038NFL 0.035 0.0023 15.16 108 0.030 0.039NHL 0.041 0.0016 24.75 118 0.038 0.044

Summer Olympics 0.027 0.0025 10.64 131 0.022 0.032

NBA Fig 1; MLB Fig 3; NFL Fig 5; NHL Fig 7; Summer Olympic Fig 9

Table 2: Player Weight Slope Validity and 95% Confidence Interval.Each Recorded P-Value < 0.001

Sport Slope Standard Error T-value DF 95% CI of Slope

Lower UpperNBA 0.493 0.0259 19.65 78 0.440 0.541MLB 0.278 0.0086 32.04 153 0.261 0.295NFL 0.500 0.0216 23.13 108 0.457 0.542NHL 0.338 0.0155 21.81 118 0.308 0.369

Summer Olympics 0.141 0.0265 5.32 121 0.089 0.193

NBA Fig 2; MLB Fig 4; NFL Fig 6; NHL Fig 8; Summer Olympic Fig 10

Figure 11: Average Height vs Decade of BirthAveraged per Decade 1940-1980

[2,4,5,6,7,8,11,12,13]Figure 12: Average Weight vs Decade of Birth

Averaged per Decade 1940-1980[2,4,5,6,7,8,11,12,13]

IV. RESULTSHeight:

Each sport had a height regression slope that was significantly different than zero as shown in Figures 1, 3, 5, 7, 9 and Table 1. NBA players have heights growing at the largest rate, with a 95% confidence interval between 0.064 and 0.0829 inches per year. NHL players were next with an interval between 0.038 and 0.045 inches, MLB players had an interval between 0.035 and 0.038 inches, and NFL players had an interval between 0.031 and 0.040 inches. Summer Olympic athletes had the smallest growth rate, with an interval between 0.022 and 0.032 inches per year.

Each sport’s data was also averaged per decade and compared with the average height of American males of the same age as shown in Table 3 and Figure 11. Each decade, the average heights of the athletes were significantly greater than the height of the average American male. The NFL has greatest change in terms of t-value due to the largest sample size per decade. The NBA has the most substantial difference in terms of average height per decade as well as the highest standard deviation for each decade.

Weight:Each sport studied had a weight regression slope

that was significantly different than zero as shown in Figures 2, 4, 6, 8, 10 and Table 2. NFL players have the largest yearly change in weight, with a 95%

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1940 1950 1960 1970 1980636567697173757779 NBA

MLB

NFL

NHL

Summer Olympics

National Average

Decade of Birth

Heig

ht (I

nche

s)

1940 1950 1960 1970 1980160

175

190

205

220

235

250 NBA

MLB

NFL

NHL

Summer Olympics

National Average

Decade of Birth

Wei

ght (

lbs)

Table 3: T-Test: Player Height to National Male Average per Decade. Each Recorded P-Value < 0.001

Sport Decade Born

Player Height

NationalHeight

St. Dev.

Number Players T-Value

NBA

1940 77.425 68.9 8.579 640 25.1381950 77.914 69.7 6.063 629 33.9731960 78.541 69.7 5.070 682 45.5361970 78.905 69.3 3.764 595 62.2401980 78.962 69.6 5.296 560 41.832

MLB

1940 72.948 68.9 2.168 1284 66.9031950 73.176 69.7 2.206 1488 60.7691960 73.350 69.7 2.230 1747 68.4241970 73.555 69.3 2.273 1995 83.6171980 73.763 69.6 2.296 1692 74.575

NFL

1940 74.004 68.9 2.102 2375 118.3231950 73.784 69.7 2.411 2918 91.4981960 73.582 69.7 2.644 3963 92.4231970 73.639 69.3 2.607 3475 98.1011980 73.825 69.6 2.580 3820 101.22

NHL

1940 71.156 68.9 1.896 663 30.6371950 71.753 69.7 1.975 1166 35.5011960 72.287 69.7 2.021 1283 45.8581970 73.006 69.3 2.029 1288 65.5521980 73.207 69.6 2.070 1265 61.968

S. O.

1940 72.076 68.9 3.717 378 16.6141950 72.307 69.7 3.813 381 13.3431960 72.335 69.7 4.074 465 13.9491970 72.596 69.3 3.886 460 18.1901980 72.787 69.6 4.062 278 13.081

[2,4,5,6,7,8,11,12,13]

Table 4: T-Test: Player Weight to National Male Average per Decade.All P-Values < 0.001 Except 1980 Summer Olympics P-Value: 0.352

Sport DecadeBorn

PlayerWeight

NationalWeight

St. Dev.

NumberPlayers

T-Value

NBA

1940 201.532 163.9 26.385 640 36.0811950 201.844 169.6 25.252 629 32.0241960 208.972 167.9 27.933 682 38.3981970 219.455 172.5 29.239 595 39.1711980 219.828 183.4 29.241 560 29.480

MLB

1940 186.136 163.9 15.211 1284 52.3791950 186.639 169.6 15.917 1488 41.2941960 189.382 167.9 17.248 1747 52.0581970 199.133 172.5 20.988 1995 56.6771980 206.054 183.4 21.813 1692 42.718

NFL

1940 221.213 163.9 27.743 2375 100.671950 220.574 169.6 31.085 2918 88.5791960 228.832 167.9 39.024 3963 98.2931970 240.615 172.5 45.242 3475 88.7511980 241.478 183.4 45.289 3820 79.260

NHL

1940 182.260 163.9 12.858 663 36.7671950 187.132 169.6 13.556 1166 44.1641960 193.876 167.9 14.439 1283 64.4351970 201.811 172.5 15.602 1288 67.4201980 202.429 183.4 15.784 1265 42.877

S.O.

1940 175.623 163.9 34.353 378 6.63461950 175.350 169.6 32.082 381 3.49881960 178.314 167.9 34.248 465 6.55731970 180.769 172.5 33.310 460 5.32461980 182.639 183.4 33.578 278 -0.377

[2,4,5,6,7,8,11,12,13]

confidence interval between 0.458 and 0.543 pounds per year. [1] NBA players were very close, with an interval between 0.440 and 0.542 pounds per year. NHL players had an interval between 0.308 and 0.369 pounds, and MLB players had an interval between 0.261 and 0.295 pounds. Summer Olympic athletes had the smallest growth rate, with a range of 0.089 and 0.194 pounds per year as shown in Table 2.

Each sport’s data was also averaged per decade and compared with the average weight of American males of the same birth year as shown in Table 4 and Figure 12. [2, 4] Each decade, the average weights of the athletes were considerably greater than the weight of the average American male, with the exception of the Summer Olympic athletes born in the 1980s. These athletes have, on average, a lower body weight than the average American male (t-value: -0.377 p-value: 0.35). The NFL has the most significant change in terms of t-value again due to the largest sample size per decade. The NFL also has the greatest difference in terms of average weight per decade as well as the highest standard deviation per decade. [4,5]

V. CONCLUSIONSThe research showed that, professional and

Olympic male athletes are getting larger each year and have a significantly larger height and weight than the average US male of the same age.

This research may be used to predict the future size of athletes or make more generalizations to the average American. It may be interesting to look into the history of the sports studied and use that history to explain the fluctuation in athlete height and weight. For example, the first 30 years of NHL data has no obvious pattern from year to year. This may be attributed to having few teams in the NHL at the time, the lack of available players, or a number of other factors.

There was an attempt to gain data for statistics on professional soccer players, but no easily accessible database was available. With more time, the research would make more comparisons, such as the growth rate of height and weight against the growth rate of the average American.

ACKNOWLEDGMENTThis work was funded by the US National

Science Foundation (NSF) Research Experience for Teachers (RET) 1301089 in the Department of Computer Science at Appalachian State University in Boone, North Carolina. Special thanks to Dr. R. Mitchell Parry and Dr. Rahman Tashakkori for their help and guidance.

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http://journals.lww.com/nscajscr/Fulltext/2013/02000/Changes_in_Height,_Body_Weight,_and_Body.1.aspx[2] B. Barnwell, Mere Mortals: What we learned by comparing the mortality rates of baseball players and their NFL counterparts (Aug. 16, 2012).  Available http://www.grantland.com/story/_/id/8274392/comparing-mortality-rates-football-baseball [3] D. Derbyshire, Revealed: How world's top athletes have become taller and bigger (and faster) over past 100 years, Mail Online: Science and Technology, (Tuesday, July 16, 2013), Availablehttp://www.dailymail.co.uk/sciencetech/article-1200174/Top-athletes-track-faster-taller-predecessors.html[4] M. Hathaway, Available, Trends and Heights in Weight, The Yearbook of Agriculture, 1959, Food, United States Department of Agriculture, US Government Printing Office,http://science-in-farming.library4farming.org/Food-Nutrition-Allowances/HEALTH/Heights-and-Weights.html[5] J. Komlos. M. Brabec, The evolution of BMI values of US adults: 1882-1986. August 31. 20 Available,

http://www.voxeu.org/article/100-years-us-obesity[6] S. Lahman. (2013). Baseball Database, Creative Commons, [Online]. Available http://www.seanlahman.com/baseball-archive/statistics/[7] C.Lee (2013). Baseball Player Height and Weight by Year. University of Oregon, [Online]. Availablehttp://sportsologist.com/baseball-player-height-and-weight-by-year/[8] Rotosports Inc., National Basketball Association Player Database, Available, http://www.databasebasketball.com/players/playerlist.htm[9] J. Saint Onge, P Krueger, and R. Rogers, Economics and Human Biology, 2008, Historical trends in height, weight, and body mass: Data from U.S. Major League Baseball players, 1869–1983, Symposium on the Economics of Obesity, National Institute of Health, Available,   http://www.ncbi.nlm.nih.gov/pmc/articles/ PMC2692043/[10] R. Steckel, A History of Living in the United States, Methods of Measuring Standards of Living, Ohio State University, (January 02, 2010), Available, http://eh.net/encyclopedia/article/steckel.standard.living.us[11] USA Today Sports Digital Properties, National Football League Player Database. Available, http://www.pro-football-reference.com/players/[12] USA Today Sports Digital Properties, National Hockey League Player Database.  Available, http://www.hockey-reference.com/players/[13] USA Today Sports Digital Properties, US Summer Olympic Player Database.  Available, http://www.sports-reference.com/olympics/summer

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