Defensive Linemen Research Articles

Epidemiology of College Athlete Sizes, 1950s to Current

The purpose of this study is to examine the epidemiology and trends of body size in college athletics. Data were coded from available athlete rosters from four division 1 college athletic programs for football, basketball, baseball, and men's/women's tennis for the period of 1950 to the present. Data on 17,500 football, 2,470 basketball, 3,868 baseball, 903 men's tennis, and 765 women's tennis athletes were entered. Increases in height, weight, and body mass index (BMI) were seen for all sports at most positions, but the greatest increases were observed in football offensive and defensive linemen. The largest increases in weight and (BMI) were observed amongst football offensive and defensive linemen, placing them at greatest risk for size-related medical complications. Other college sports exhibit increases in height, weight, and BMI as well, but the rates of increase were not as great.

Upper Extremity Injuries in the National Football League

Background Very little has been published regarding the incidence of and duration of time lost after hand injuries in professional American football players. Hypotheses (1) Hand, first ray, and finger injuries in professional American football players represent a common cause of missed time from practice and game participation. (2) The effect of upper extremity injuries differs as a function of the anatomic site involved, injury type, and athlete's position. Study Design Descriptive epidemiologic study. Methods A retrospective review of all documented injuries to the hand, first ray, and fingers sustained by American football players in the National Football League over a 10-year period (1996–2005) was performed using the League's injury surveillance database. The data were analyzed from multiple perspectives, with emphasis on the type of injury, athlete position, and activity at the time of injury. Results A total of 1385 injuries occurred to the hand, first ray, and fingers over the 10 seasons studied. Of these injuries, 48% involved the fingers, 30% involved the first ray, and 22% involved the hand, with game injuries more common than practice injuries at each location. Metacarpal fractures and proximal interphalangeal joint dislocations were the 2 most common injuries. Offensive and defensive linemen were the most likely to sustain a hand injury; 80% of hand injuries were metacarpal fractures. The most common injuries to the first ray were fractures (48%) and sprains (36%), which occurred most often in athletes playing a defensive secondary position. Finger injuries were most commonly dislocations at the level of the proximal interphalangeal joint, typically involving the ulnar 2 digits. Finger injuries were most common in wide receivers and defensive secondary players. The act of tackling produced the most injuries (28%). Conclusion Upper extremity trauma, especially injury to the hand, first ray, and fingers, is a significant source of morbidity for professional football players. The results of this study may be used to implement preventive measures to help minimize these injuries.

Multiclonal outbreak of methicillin-resistant Staphylococcus aureus infections on a collegiate football team

An outbreak of methicillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infections (SSTIs) occurred in a college football team in August 2006. Of 109 players on the team roster, 88 (81%) were interviewed during a cohort investigation. Twenty-five cases were identified, six of which were culture-confirmed. Available culture isolates were typed by pulsed-field gel electrophoresis (PFGE), which identified two different MRSA strains associated with the outbreak. Playing positions with the most physical contact (offensive linemen, defensive linemen, and tight ends) had the greatest risk of infection [risk ratio (RR) 5.1, 95% confidence interval (CI) 2.3-11.5. Other risk factors included recent skin trauma (RR 1.9, 95% CI 0.95-3.7), use of therapeutic hydrocollator packs (RR 2.5, 95% CI 1.1-5.7), and miscellaneous training equipment use (RR 2.1, 95% CI 1.1-4.1). The outbreak was successfully controlled through team education and implementation of improved infection-control practices and hygiene policies.

An Evaluation of the Body Size of High School Football Players in Northeastern Pennsylvania over Three Decades

INTRODUCTION: Position demands and competitiveness to obtain an athletic scholarship may have forced high school football players to modify their body size. Research spanning 30 years have evaluated this issue in collegiate and professional football athletes. PURPOSE: To evaluate differences among football positions and body size of high school football players in Northeastern Pennsylvania across three decades. METHODS: This retrospective study examined 574 high school football players from one AA high school in Northeastern Pennsylvania. AA high school size classification represents enrollment for males grades 9–12 of no more than 330. Review of program rosters were used to collect position, height, weight and academic classification. Data was provided for program rosters by either school nurse or certified athletic trainer. All positions of play were examined and compared over three decades (1970-2000). RESULTS: Offensive and defensive lineman (OL, DL) had a mean (SD) height of 70.58 (2.58) inches with a mean (SD) weight of 196.13 (34.27) pounds. Mean (SD) BMIfor OL and DL was 27.66 (4.15) compared to a BMI of 22.09 (1.71) for defensive backs and wide receivers. A One-way ANOVA with repeated measures revealed a significant difference (p<0.05) across decades for weight. No significant differences (p>0.05) were found across decades for either height or BMI. CONCLUSIONS: Weight of high school football players has increased over the past three decades. The impact on the health of these athletes warrants investigation.

Rapid Cooling Of An NFL Defensive Linemen With A Core Temperature Of 40.9 2C During A Full Padded Practice

HISTORY The athlete is a 9 yr veteran defensive lineman in the National Football League (NFL) with age = 30 yr, height =182.9 cm and body fat = 24%. He arrived at pre-season training camp 2004 with mass = 149 kg, similar to his 2003 pre-season mass (147.7 kg). He gained 5.6 kg by the 5th morning, 3.76% above baseline (BL). His sweat rate was 1.7 l·hr-1 in 2003 with ambient temperature = 23.7 °C and 83% RH. In pre-season 2003 his mean percent dehydration (%Dehy) after practice was 0.87% ranging from 0.0 to 1.85% in 23 consecutive practices. During the first 3 days of the 2004 pre-season this player's core temperature (Te) was monitored using ingestible sensors (HQ, Inc.). On Day 1 of two-a-days, his Te was >39.5°C (103°F) at the end of a one h indoor morning (AM) practice. Wet bulb globe temperature (WBGT) was 24.4°C and he was dressed in a helmet, shorts and shell. He denied a history of heat associated illness. PHYSICAL EXAMINATION The subjects' Te was closely monitored during the afternoon (PM) full padded practice due to his elevated AM Te. While dressed in shorts and a Tee-shirt, his resting Te recorded in an air-conditioned area 45 min prior to PM practice was 37.8°C (100°F). His Te was monitored approximately every 8 min during PM practice and he was questioned frequently about heat-related symptoms. His Te steadily increased to 40°C (104°F) by 1 h and 30 min into practice and he denied symptoms other than he felt hot. When his Te increased to 40.6°C (105°F) he was removed from practice against his will. His equipment was removed and he was transported to the on-field medical tent. Mean WBGT assessed three times during practice was 28.3°C. DIFFERENTIAL DIAGNOSIS Malignant hyperthermia Exercise induced heat stroke Exercise associated hyperthermia (benign) TEST AND RESULTS Te monitoring (40.9°C which decreased with cooling) Cognitive testing (−) Visual assessment (+ mild visual disturbance) % Dehydration (0% from baseline) FINAL WORKING DIAGNOSIS Benign exercise associated hyperthermia. TREATMENT AND OUTCOMES The athlete was removed from practice and rapidly cooled with ice-water soaked vests, neck collars and caps. His Te increased from 40.6°C when removed from practice to 40.9°C (105.7°F) just prior to aggressive cooling. While Te was continuously monitored the ice-water vests, collars and caps were changed approximately every 45 – 90 sec. A total of 6 changes were used for this player. Tc decreased from 40.9°C to 38.7°C (101.7°F) within 10 min of cooling. He had no residual symptoms or subsequent heat-associated problems. His post-practice % Dehy was 1.36% from pre-practice but 0% from BL. The highest Te recorded in this athlete on the 10th day of pre-season was 39.4°C (103°F).

Rapid Cooling Of An NFL Defensive Linemen With A Core Temperature Of 40.9 2C During A Full Padded Practice

Rapid Cooling Of An NFL Defensive Linemen With A Core Temperature Of 40.9 2C During A Full Padded Practice

Body Size and Composition of National Football League Players

The purpose of this study was to present a profile of body size and composition of National Football League (NFL) players prior to the start of the regular season. Fifty-three members of the Indianapolis Colts professional football team were measured for height, body mass, and percentage body fat using the BOD POD air-displacement plethysmography system during summer camp of the 2003 football season. These data were categorized by position for comparison with previous studies of NFL football players. The relationships observed were as follows (= represents nonsignificant; > represents p < or = 0.05): Height: Offensive Line = Defensive Line = Quarterbacks/Kickers/Punters = Tight Ends > Linebackers > Running Backs = Wide Receivers = Defensive Backs. Body Mass: Offensive Line = Defensive Line > Tight Ends = Linebackers > Running Backs = Quarterbacks/ Kickers/Punters > Wide Receivers = Defensive Backs. Percentage Body Fat: Offensive Line > Defensive Line > Quarterbacks/ Kickers/Punters = Linebackers = Tight Ends > Running Backs = Wide Receivers = Defensive Backs. Comparisons to teams in the 1970s indicate that body mass has increased only for offensive and defensive linemen; however, height and body fat among player positions have not dramatically changed. Furthermore, the body mass index is not an accurate measure or representation of body fat or obesity in NFL players. These data provide a basic template for size profiles and differences among various positions and allow comparisons with other studies for changes in the NFL over the past 3 decades.

Equipment and Running Surface Alter Sprint Performance of College Football Players

The purpose of this study was to determine the effect of football equipment and running surface on sprint performance in NCAA Division II football players (n = 68). Players were timed in the 40-yd sprint on an indoor rubberized track (Day 1) and on an outdoor, natural-grass football field (Day 2) wearing either regulation football equipment or shorts and a T-shirt. Each player was assigned randomly to perform 2 trials under each condition on each surface, and the average of the 2 trials was used for analysis. Offensive backs, defensive backs, and linebackers were significantly faster than were offensive and defensive linemen in all trials, and subjects were collapsed into 2 groups, backs and linemen. Football equipment significantly impaired performance on the track (-2.8% +/- 1.7%) and the field (-2.9% +/- 1.8%). The increase in body mass due to the football equipment was significantly greater for backs (7.2% +/- 0.7%) than for linemen (6.5% +/- 1.0%), but produced a significantly greater impairment in sprint performance in linemen (-3.3% +/- 1.1%) as compared with backs (-2.5% +/- 1.5%). Sprint performance was significantly and equivalently impaired when running on grass (backs: -2.5 +/- 1.1%; linemen: -2.8 +/- 1.4%) as compared with the track. Thus, running a 40-yd sprint in football equipment on a natural grass field impairs performance by an average of 5.5% (+/- 2.3%) compared with running indoors with minimal apparel. Football equipment and running surface significantly impair sprint performance in college football players, the effect being greater in linemen than in backs, and is likely related to differences in muscle strength/power and body fat.

Injuries in Youth Football

1885 PURPOSE: To estimate injury rates and variation in injury by grade, severity, type and position in a youth football population. Surveys of youth participants generally lack suitable exposure data for practices and competitions to permit estimates of injury rates. METHODS: Participants (n = 354, 9–14 years) in two community youth football leagues in mid-Michigan were followed throughout a single season, mid-August through October. Grade in school was the unit of competition. A certified athletic trainer was on sight for practices and home games to record exposure statistics and injuries as they occurred; injuries occurring in road games were reported by coaches and verified the next day by the trainers. The sample was split into younger (4–6th grades) and older (7–8th grades) groups for analysis. RESULTS: Estimated injury rates were significantly higher in 7–8th (16.2/1000 athlete exposures) compared to 4–6th (7.5/1000 athlete exposures) grades (p<0.001). Among 7–8th grade players, defensive linemen and defensive backs had a significantly higher frequency of injuries compared to respective positions in the 4th-6th grade players (p = .014). There were no significant differences in injuries by severity and type and in severity by position between the 4–6th and 7–8th grades. General trauma constituted 40% of all injuries (50% in 4–6th and 36% in 7–8th grades), and the majority of injuries were classified as minor (80% in 4–6th and 72% in 7–8th grades). CONCLUSIONS: Estimated injury rates increase with grade and probably age. Most injuries in youth football are minor and similarly distributed between grades. There are no clear trends in the distribution of injuries by type and in severity by position. Supported by the National Athletic Trainers' Association Foundation (Grant Number 300R001) and a Wohlgamuth Fellowship at Michigan State University.

Injuries in Youth Football

1885 PURPOSE: To estimate injury rates and variation in injury by grade, severity, type and position in a youth football population. Surveys of youth participants generally lack suitable exposure data for practices and competitions to permit estimates of injury rates. METHODS: Participants (n = 354, 9–14 years) in two community youth football leagues in mid-Michigan were followed throughout a single season, mid-August through October. Grade in school was the unit of competition. A certified athletic trainer was on sight for practices and home games to record exposure statistics and injuries as they occurred; injuries occurring in road games were reported by coaches and verified the next day by the trainers. The sample was split into younger (4–6th grades) and older (7–8th grades) groups for analysis. RESULTS: Estimated injury rates were significantly higher in 7–8th (16.2/1000 athlete exposures) compared to 4–6th (7.5/1000 athlete exposures) grades (p<0.001). Among 7–8th grade players, defensive linemen and defensive backs had a significantly higher frequency of injuries compared to respective positions in the 4th-6th grade players (p = .014). There were no significant differences in injuries by severity and type and in severity by position between the 4–6th and 7–8th grades. General trauma constituted 40% of all injuries (50% in 4–6th and 36% in 7–8th grades), and the majority of injuries were classified as minor (80% in 4–6th and 72% in 7–8th grades). CONCLUSIONS: Estimated injury rates increase with grade and probably age. Most injuries in youth football are minor and similarly distributed between grades. There are no clear trends in the distribution of injuries by type and in severity by position. Supported by the National Athletic Trainers' Association Foundation (Grant Number 300R001) and a Wohlgamuth Fellowship at Michigan State University.

COMPARISON OF PHYSICAL AND PERFORMANCE CHARACTERISTICS OF NCAA DIVISION I FOOTBALL PLAYERS

The purpose of this study was to compare normative data from present Division I National Collegiate Athletic Association football teams to those from 1987. Players were divided into 8 positions for comparisons: quarterbacks (QB), running backs (RB), receivers (WR), tight ends (TE), offensive linemen (OL), defensive linemen (DL), linebackers (LB), and defensive backs (DB). Comparisons included height, body mass, bench press and squat strength, vertical jump, vertical jump power, 40-yd-dash speed, and body composition. Independent t-tests were used to analyze the data with level of significance set at p < 0.01. Significant differences (p < 0.01) were found in 50 of 88 comparisons. From 1987 until 2000, Division I college football players in general have become bigger, stronger, faster, and more powerful. Further research is warranted to investigate if these trends will continue.

Exit Discrimination in the NBA: A Duration Analysis of Career Length

Using a panel study of annual NBA data (1989–99) we do not find evidence of exit discrimination on career length in the NBA. This result is inconsistent with results from data in the 1980s but is consistent with more recent findings that have measured wage discrimination in sports in the 1990s. In our semiparametric duration analysis, we find that performance variables are important in determining career length. These results suggest that team owners in the pursuit of championships keep talented players regardless of race. This is an affirmation of Becker's theoretical implications of market competition on discrimination. (JEL J71, J23)

The National Football League combine: a reliable predictor of draft status?

The performance of 326 collegiate football players attending the 2000 National Football League combine was studied to determine whether draft status could be predicted from performance measurements. The combine measured height and weight along with 9 performance tests: 225-lb bench press test, 10-yd dash, 20-yd dash, 40-yd dash, 20-yd proagility shuttle, 60-yd shuttle, 3-cone drill, broad jump, and vertical jump. Prediction equations were generated for 7 position categories with varying degrees of accuracy-running backs (RBs), r(2) = 1.00; wide receivers (WRs), r(2) = 1.00; offensive linemen, r(2) = 0.70; defensive linemen, r(2) = 0.59; defensive backs (DBs), r(2) = 1.00; linebackers, r(2) = 0.22; and quarterbacks, r(2) = 0.84. The successes of the prediction equations are related to the ability of the individual tests to assess the necessary skills for each position. This study concludes that the combine can be used to accurately predict draft status of RBs, WRs, and DBs. The equations can also be used as a good to fair estimate for other positions.

Peak Flow Measurements in Professional Football Players

Introduction: At training camp for the 1996 NFL Philadelphia Eagles, there was an athlete who suffered acute reactive airway disease. Peak flow measurements at the time of acute exacerbation and obvious respiratory distress were notable for being over 600, well within the normal range for this player's height and age. An extensive review of the literature revealed no prior published reports of peak flow measurements of professional football players in the United States. Watson describes pulmonary function in Irish soccer players, and Van Handel, et al. Studied pulmonary function in Olympic athletes. The purpose of this study was to determine the normative values of peak flow and pulmonary function tests in a population of NFL players, and to determine the difference, if any, with standard values. The corollary clinical aspect is that if the normative values are different, are we missing RAD in the population? Methods: The population is NFL Philadelphia Eagles 1996 entire roster, 70 players. Hand held peak flow measurements x 3 were recorded and pulmonary function measurements (FEV1, FVC, FEV1/FVC, FEF25-75, PEFR) using the same machine by Respi-Tech and the same technician were recorded. Predicted and percent predicted were derived based on the standard equation using sex, age and height. Mean values were determined for this population (minus the seven players with history of RAD). Body mass index and peak flow measurements and pulmonary function tests were analyzed by Pearson correlation analysis for statistical significance. A prior study by Gary and McShane showed that the players could be divided into three groups by BMI: quarterbacks, running backs and cornerbacks (herein, “SKILL”); tight ends, defensive ends, and linebackers (herein, “LB/TE”); and offensive and defensive linemen (herein, “LINE”). Mean values of peak flows by these positions were also determined and analyzed for statistical significance. Results:TableBy Pearson correlation analysis, an inverse linear relation was found between BMI and FEV1/FVC with p < .05. No other statistically significant correlation between BMI and FEV1, FVC, FEF25-75, PEFR, or hand held peak flow measurements were found.TableThere was no statistical significant relationship between position grouping and pulmonary function as determined by Pearson correlation analysis. Discussion: Despite the large height and athletic prowess of this population, their peak flow measurements were not different than normative values. Actually, all of the percent predicted values were less than 100%. Should we determine norms for this unique population by testing more athletes of this size? Perhaps standard pulmonary function equations can not apply to this population and new equations need to be derived. There were differences in pulmonary function based on position grouping by BMI, however it was not statistically significant. Since there are few measures of “fitness” in elite athletes, could pulmonary function be a measure. In this specific athletic group this may have an impact on recruiting US football players at many levels.

Prevalence of headaches in football players.

Football coaches and team physicians rely heavily on players' reports of symptoms in deciding whether a player may return to the game after sustaining head trauma. The decision is made difficult by the wide variety of associated symptoms, some of which (e.g., headache is among the most common) may or may not be associated with serious head injury. More information is needed about the clinical significance of football-related headache. To assess the frequency of headache associated with playing football, we analyzed responses to our questionnaire asking about incidence, frequency, and outcome of football-related headache from 443 football players (320 from college, 123 from high school). Eighty-five percent of respondents reported previous headache related to hitting in football. Asked specifically about their most recent game, 21% of respondents reported having had headache during that game. Of players who had headache, only 19% informed the team physician, trainer, or coach, and only 6% were removed from the game. Twenty-seven percent of respondents reported previous diagnosis of cerebral concussion by medical personnel. Defensive backs (25%), defensive linemen (19%), and offensive linemen (18%) were most likely to have headache, related to hitting. Our data confirm that posttraumatic headache is commonly associated with football participation and often goes unreported. Given that the most serious complications of head injuries (e.g., second-impact syndrome) occur infrequently, headache as an isolated symptom lacks specificity in predicting such complications in football players. Therefore, unless it persists or is accompanied by additional symptoms, headache alone may not reliably suggest the need to remove players from the game.

Strength and Physiological Characteristics of NCAA Division III American Football Players

ABSTRACT The purpose of this study was to examine strength and physiological parameters in 78 American football players who reported for the 1994 and 1995 preseason football training camp at a National Collegiate Athletic Association (NCAA) Division III college. The athletes were each tested one time for explosive power, upper-body strength, lowerbody strength, muscular endurance, speed endurance, lower-body flexibility, and body composition. The performance data were analyzed according to position and playing status (starter vs. nonstarter). Significant (p ≤ 0.05) differences were observed between positions for all but the sit and reach test. For measures of muscular and speed endurance and lower-body explosive power, defensive backs scored the highest, whereas for measures of upper- and lower-body strength and upper-body explosive power, defensive linemen scored the highest. Starters performed significantly better than nonstarters for the seated medicine ball put, bench press, and hip sled. Further investigation that includes more NCAA Division III players from different institutions and regions is still warranted.

Posterior labral injury in contact athletes.

Nine athletes (seven football offensive linemen, one defensive lineman, and one lacrosse player) were found at arthroscopy to have posterior labral detachment from the glenoid. In our series, this lesion is specific to contact athletes who engage their opponents with arms in front of the body. All patients had pain with bench pressing and while participating in their sport, diminishing their ability to play effectively. Conservative measures were ineffective in relieving their symptoms. Examination under anesthesia revealed symmetric glenohumeral translation bilaterally, without evidence of posterior instability. Treatment consisted of glenoid rim abradement and posterior labral repair with a bioabsorbable tack. All patients returned to complete at least one full season of contact sports and weightlifting without pain (minimum follow-up, > or = 2 years). Although many injuries leading to subluxation of the glenohumeral joint occur when an unanticipated force is applied, contact athletes ready their shoulder muscles in anticipation of impact with opponents. This leads to a compressive force at the glenohumeral joint. We hypothesize that, in combination with a posteriorly directed force at impact, the resultant vector is a shearing force to the posterior labrum and articular surface. Repeated exposure leads to posterior labral detachment without capsular injury. Posterior labral reattachment provides consistently good results, allowing the athlete to return to competition.

An Empirically Based Selection and Evaluation System for Collegiate Football

Using a content validity approach, including job analysis, a model was developed for the selection and appraisal of college football players. Evaluation instruments were developed for offensive lineman, quarterback, running back, receiver, defensive lineman, linebacker, and defensive secondary. Criterion related validity studies were then conducted by sending the evaluation instruments to a nation-wide sample of college football coaches who evaluated players at each position. Criterion data (e.g., passing and rushing performance statistics) were collected on the evaluated players. Multiple linear regression analyses conducted by position revealed numerous significant relationships between the predictor variables and the criterion measures. The usefulness of the evaluation instruments was enhanced by developing a simple and cost effective model that generated performance predictions for each position. Strengths and weaknesses of the present system were discussed as well as the role that sport management may play in such an endeavor.

SHOULDER INJURY - FOOTBALL

302 HISTORY - A 19-year-old elite college football defensive lineman sustained a shoulder injury while tackling another player during a practice scrimmage. During the tackle another player fell on the back of his abducted left shoulder. He noted immediate pain and weakness in his shoulder. He denied paresthesias. He reported his symptoms to the athletic trainers and was taken out of the game. PHYSICAL EXAMINATION - Initial examination on the sidelines revealed no deformity of the shoulder. There was moderate tenderness in the posterior aspect of the left shoulder overlying the infraspinatus and trapezius muscles. Range of motion was limited in elevation and rotation secondary to pain. He was able to fire all muscle groups, but had weak deltoid, supraspinatus and external rotators. He denied any neck tenderness and he had normal sensation in the extremity. The affected arm was placed in an arm sling on the sidelines and ice was applied. His shoulder was re-examined after icing. There was still significant tenderness to palpation and pain with any attempted motion of the left shoulder. The pain progressively worsened and required narcotic analgesics. DIFFERENTIAL DIAGNOSIS: Anterior left shoulder dislocation Traumatic rotator cuff injury Scapular fracture Brachial plexus neuropraxia “stinger” TESTS AND RESULTS: RADIOGRAPHS: Left shoulder AP, True AP, and axillary: humeral head located normally on the glenoid an area of lucency at the neck of the scapula, that appears consistent with a vascular groove CT SCAN Left shoulder without contrast: (axial and coronal reconstruction in 5 mm increments) -Non-displaced vertical extra-articular fracture through the glenoid base of the left shoulder FINAL/WORKING DIAGNOSIS: Non-displaced left scapular glenoid base fracture TREATMENT: Immobilization in a shoulder immobilizer for 2 weeks Pendulum exercises and range of motion exercises 2 weeks after the injury. Rotator cuff and deltoid strengthening exercises for 3 and 4 weeks post injury. Cardiovascular workouts continued throughout rehabilitation Phased back to contact once near full strength achieved at 2 months post injury.

A physiological review of American football.

American football has been one of the most popular sports in North America within the past century and has recently received support and increased participation from European nations. Two of the biggest concerns regarding participation in American football are the high incidence of injury and the physical demand for preparation. A basic understanding of the physiological systems utilised in the sport of football is necessary in order to develop optimal training programmes geared specifically for preparation as well as the requirements of individual field positions. Previously, it has been assumed that football relies primarily on an anaerobic source of energy for adenosine triphosphate (ATP) resynthesis with approximately 90% coming from the phosphocreatine (PCr) energy system. In lieu of research conducted specifically with football players, it appears that the energy contribution from the anaerobic glycolytic pathway in this sport has been underestimated. The elevated blood lactate levels observed in football players following game participation cast doubt on this hypothesis. Identifying position specific characteristics may also enhance the development of training programmes based on the requirements of the different positions. It appears that offensive and defensive linemen are generally larger, have higher levels of percent body fat and have greater absolute strength scores than all other positions. Offensive backs, defensive backs and wide receivers tend to display the lowest percentages of body fat, lower absolute strength scores, fastest times over 5, 10, 40 and 300m and the highest relative VO2max values. Linebackers appeared to represent a transition group mid way between the backs and linemen for size, body composition, strength, speed and endurance as well as positional duties. Findings within the literature suggest that a lack of cardiovascular development of university and professional football players may prove to be a hindrance to performance with specific regards to thermal regulation. Additional aerobic conditioning as well as the reduction of percent body fat would not only enhance performance, but might play a key role in preventing injuries and allowing a smoother transition into life after football.