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Evaluation of the Physical Test Battery Implemented at the National Football League Combine

Robbins, Daniel W. PhD, CSCS; Goodale, Tyler MSc, CSCS

Strength and Conditioning Journal: October 2012 - Volume 34 - Issue 5 - p 1–10
doi: 10.1519/SSC.0b013e31826210e1
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SUMMARY THE PURPOSES OF THIS REVIEW WERE TO EVALUATE THE PHYSICAL TEST BATTERY CURRENTLY IMPLEMENTED AT THE NATIONAL FOOTBALL LEAGUE (NFL) COMBINE AND TO MAKE RECOMMENDATIONS BASED ON POSITIONAL REQUIREMENTS. DEPENDING ON THE POSITION, VERY DIFFERENT SKILL SETS ARE NECESSARY FOR SUCCESS IN AMERICAN FOOTBALL. EVALUATION OF THE CURRENT NFL COMBINE BATTERY DETERMINED THAT MANY POSITIONS PERFORM TESTS NOT OF PARTICULAR IMPORTANCE TO THAT POSITION. IT IS RECOMMENDED THAT 4 TESTS REPLACE THE CURRENT 6. THESE INCLUDE THE 36.6-M SPRINT WITH SPLIT TIMES, LOWER- AND UPPER-BODY MAXIMAL STRENGTH MEASURES, AND A DIRECT MEASURE OF LOWER-BODY POWER.

Canadian Sport Centre Pacific, Victoria, British Columbia, Canada

Figure

Figure

Daniel W. Robbinsis an associate researcher at the Canadian Sport Centre Pacific.

Figure

Figure

Tyler Goodaleis the lead strength and conditioning coach at the Canadian Sport Centre Pacific.

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INTRODUCTION

Physical test batteries are routinely used at both the amateur and professional levels of sport to evaluate performance characteristics for the purposes of monitoring training adaptation and player selection. Commonly, test batteries are made up of measures evaluating various attributes. As part of its evaluation of future prospects, the National Football League (NFL) implements such a test battery at its annual combine. Specifically, the combine battery is made up of the 36.6-m sprint with split times at 9.1 and 18.3 m; vertical and horizontal jump measures; the 18.3-m shuttle and 3-cone drill, designed to measure change-of-direction ability; and the 102.1-kg bench press for maximum repetitions as a measure of upper-body strength. Players representing all positions are invited to the combine and, with very little exception, perform a similar battery of tests.

NFL team rosters are large (up to 53 players) and are made up of position-specific players requiring very different skill sets. Although commonalities may exist among various positions, arguably each position making up an American football roster requires somewhat unique skills or level of skill(s). For example, there is little doubt that linemen require different athletic attributes for success as compared with those required for success at the defensive back positions (21). Arguably, within the lineman (center [C], offensive guard [OG], offensive tackle [OT], defensive tackle [DT] and defensive end [DE]) or defensive back (cornerback [CB], free [FS], and strong safeties [SS]) positions, different skills, or level of skill(s), are required. Such position-specific skill requirements in American football have been supported by previous research (2,4,21,25). Given that skill requirement is dependent on the position, the fact that all positions (with very little exception) perform a similar series of physical tests at the annual NFL combine is somewhat counterintuitive. Although speed over distances greater than 36.6 m may be important at some positions (e.g., wide receiver [WR]), it is difficult to see the relevance for others (e.g., OG).

That different positions within an American football roster require different skills intuitively drives the necessity for test batteries specific to position, or group of “semihomogenous” positions. Given the resources, physical test batteries should be carefully designed with this in mind. A number of considerations deserve attention, including (a) analysis of the skills necessary to achieve success at specific positions, (b) determination of the tests to measure those skills, and (c) assurance that the decided upon tests measure independent motor skills. The current NFL combine test battery could benefit from such considerations. Thus, the purposes of this article are to evaluate the current NFL combine test battery, determine positional skill requirements of an NFL roster, and make recommendations for tests to measure those skills.

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EVALUATION OF THE CURRENT BATTERY

The NFL combine test battery is made up of 6 tests (note that the 54.9-m shuttle run has not been included because it would seem to be performed inconsistently and seldom). With the exception of the quarterback [QB] and WR positions, which are exempt from performing the bench press test and the kicker and punter positions (which only perform the 36.6-m sprint), all positions perform all tests. Following is a description and evaluation of these tests.

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36.6-m SPRINT

From a 3-point stance, players run 36.6 m as fast as possible with split times recorded at 9.1 and 18.3 m. Thus, the 36.6-m sprint test provides 3 separate outcome measures. The 9.1- and 18.3-m sprints are measures of acceleration. Previous research has shown that near maximal speed is achieved by 18.4 m in college American football players (4). Research has also shown that depending on position, or group of positions, the correlations between the 9.1-m and 18.3-m sprints range between 0.745 and 0.942 in elite American football players (21,22). Such strong correlations suggest that the measures assess similar attributes or that performance in one test may predict performance in the other.

Although the 36.6-m sprint is a measure of maximum speed, it is affected by acceleration. A “more pure” measure of maximum speed would exclude the acceleration phase. To better understand the strengths and weaknesses of a player, separate and unaffected measures of acceleration and maximum speed are preferable and may provide insight into selection preference for draft personnel. Furthermore, that lineman positions perform this test is confusing. The rationale underlying why positions who seldom sprint more than 5–10 m perform a 36.6-m sprint for evaluation purposes is not obvious.

That this test is run from a 3-point stance for all players is perhaps inconsistent with sport-specific starting position. Most positions do not begin plays from a 3-point stance. Although this allows for consistency across positions, and thus effective comparison across positions, such comparisons are likely unnecessary. Of greater importance is the accurate comparison of the ability within position in competition-like settings. As many positions do not start plays from a 3-point stance, it would seem somewhat ambiguous to measure and subsequently evaluate players in a test dissimilar to that which is common to competition.

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VERTICAL JUMP

The vertical jump test is a measure of vertical jump ability. Jump height is measured using a device (e.g., Vertec™ Vertical Jump Tester) whereby players jump for maximal height from a standing 2-footed position in a countermovement manner with arm swing. At the peak of the jump, the player reaches as high as possible with a single hand to move horizontal vanes of the Vertec™ Vertical Jump Tester. Vertical jump height is calculated by subtracting the player's standing reach height from the height of the highest vane moved. Although vertical jump ability may be a useful skill for some positions (e.g., WR), it is difficult to see the relevance to other positions (e.g., center). If it is being conducted as an indirect measure of strength and/or power, interpretation of the outcome should be with care. Some research has suggested that the relationship between countermovement jump height, and strength and power is weak (5). Arguably, alternative tests that could be conducted at the NFL combine may better measure strength and power.

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HORIZONTAL JUMP

Horizontal jump distance is measured. From a standing 2-footed position, players jump forward for maximal distance using a countermovement and arm swing. Jump distance is measured as the distance from the start line to the nearest body part upon landing (this is typically the point of heel contact). It is difficult to imagine the applicability of horizontal jump ability to American football. If, as is suspected with the vertical jump, horizontal jump outcomes are being interpreted as representative of lower-body strength and/or power, care should be taken. Research indicates that there is little association between horizontal jump ability, and strength and power (15). Furthermore, if both the vertical and horizontal jumps are being used as indirect measures of strength and/or power, the need for both is questionable.

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18.3-m SHUTTLE

From a 3-point stance, players run 4.6 m in one direction, quickly change direction and run 9.1 m in the opposite direction, and then change direction again and run a final 4.6 m in the opposite direction (i.e., the direction initially run). The test is run in both directions (i.e., left and right) for maximum speed, and the average of the 2 tests is recorded as the score. The 18.3-m shuttle run has been suggested to measure change-of-direction ability (2).

Although a measure of change-of-direction ability, arguably it is not representative of competition-like situations and thus not indicative of a player\x{2019}s ability to effectively change directions in response to circumstances common to competition. Specifically, the 18.3-m shuttle test is a predetermined route involving no reactive component. Even offensive players running predetermined pass routes (e.g., WRs) must react to varying circumstances. Arguably, defensive players predominantly change direction in response to cues provided by the offensive players they are responsible for defending. Furthermore, it is again not obvious why players not competing from a 3-point stance are tested from such a start position.

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THREE-CONE DRILL

Players run around 3 cones placed in the shape of an “L,” with 4.6 m between the cones. From a 3-point stance, players run a predetermined route as quickly as possible. The 3-cone drill also measures change-of-direction ability (11). For reasons similar to those presented with respect to the 18.3-m shuttle (nonreactive and start stance), the 3-cone drill is perhaps not the most consistent (with sport-specific performance) test of change-of-direction ability in American football players. As with the linear sprints and 18.3-m shuttle run, to best evaluate competitive abilities, testing should mimic competition as closely as possible and thus, a 3-point start stance is inappropriate for all positions. Furthermore, it is unclear why 2 tests of change-of-direction ability are included in the current battery.

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BENCH PRESS

Players bench press 102.1 kg for maximum repetitions to measure upper-body strength. Research has demonstrated that the repetitions achieved range between 16.23 in the CB position to 29.14 in the DT position (21). Because of the nature of this test (i.e., relatively high repetitions achieved across all positions), it can be considered a measure of upper-body strength endurance, rather than maximal strength. While upper-body strength endurance may be an important characteristic in American football, maximal strength is arguably more important to most, if not all, positions. Although maximal strength can be predicted from submaximal lifts such as the 102.1-kg bench press test, the error in prediction increases as repetitions exceed 10 (12). Thus, if the purpose of the bench press test implemented at the NFL combine is to acquire a measure of maximal upper-body strength, an absolute weight of 102.1 kg may not be the best choice.

In summary, with the exception of the place kicker and punter positions, which only perform the 36.6-m sprint (no split times), and the QB and WR positions, which are exempt from the upper-body strength measure, all positions invited to the NFL combine are tested for acceleration over 9.1 and 18.3 m from a 3-point stance, a blended measure of acceleration and maximum speed over 36.6 m from a 3-point stance, vertical and horizontal jump ability, nonreactive change-of-direction ability from a 3-point stance and upper-body strength endurance. Many of these tests are unnecessary or inappropriate for some, or all, positions. Furthermore, there would appear to be redundancy in terms of motor skill measured. Of the skills measured at the combine, with the exception of place kickers and punters, arguably acceleration and change-of-direction ability are physical attributes necessary for success at all positions. Improvements can be made to the current measures of acceleration. Measurement of change-of-direction ability presents a more complex problem. Test recommendations will be made after determination of positional skill requirements.

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DETERMINATION OF POSITIONAL SKILL REQUIREMENTS

Before making recommendations for test measures, determination of the skills necessary for success at each position need to be identified. Detailed discussion regarding the responsibilities associated with each of the 15 positions examined is beyond the scope of this article. It is assumed that most readers are familiar with American football. For those less familiar, the Figure depicts a common offensive, and corresponding defensive, formation before the beginning of a play. Following are brief abridged descriptions of position-specific responsibilities.

Figure. C

Figure. C

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DEFENSIVE POSITIONS

  • CB: Prevent WR from catching and running with the ball; secondary support in preventing advancement of ball carriers.
  • Defensive end (DE): Contain ball carriers on running plays to the outside; pressure the QB on passing plays.
  • DT: Stop running plays up the middle; pressure the QB on passing plays.
  • Free safety (FS): Assist CBs with coverage of WRs; defend against running plays proceeding to secondary.
  • Inside linebacker (ILB): Defend running plays up the middle; assist in pass coverage.
  • Outside linebacker (OLB): Contain running plays to the outside; assist in pass coverage; pressure the QB on passing plays.
  • Strong safety (SS): Similar to FS, but with greater emphasis on stopping running plays.
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OFFENSIVE POSITIONS

  • Center (C): Snap ball to QB; block for running plays; protect QB on passing plays.
  • Fullback (FB): Block for running back (RB); carry ball; receive passes; protect QB.
  • OG: Block for running plays; protect QB on passing plays.
  • OT: Block for running plays; protect QB on passing plays.
  • QB: Receive ball from C to start play; throw passes to receivers; hand football to ball carriers.
  • RB: Primary ball carrier; receive passes; protect QB.
  • Tight end (TE): Block for running plays; catch passes; protect QB.
  • WR: Catch passes from QB; block downfield.

Table 1 identifies the physical attributes deemed important and measurable at each of the 15 positions. Note that similar to the existing battery, “football-playing abilities” are not addressed.

Table 1

Table 1

Without question, the skills identified above do not represent a comprehensive list of all skills necessary at each position. Furthermore, the underlying physical attributes necessary to successfully perform the responsibilities described above are not limited to those presented in Table 1. Rather, in an attempt to be practical, the attributes identified in Table 1 are deemed to be both of great importance to the respective positions and measurable in an efficient manner. As more than 300 athletes are tested annually at the combine, logistics and cost are variables to be considered in the construction of a test battery. The following is a description of a battery deemed valid, reliable, and practical.

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RECOMMENDED TEST BATTERIES

Issues of practicality, feasibility, and cost have been considered. The following recommendations are felt to be achievable within the current NFL combine setting. Without question, more comprehensive and sophisticated batteries could be devised, but adoption and implementation would likely be risked. Based on commonalities in skills necessary (see Table 1), positions are combined into semihomogenous groups. Four groups emerge from Table 1. These are as follows:

  1. Linemen (C, DE, DT, OG, and OT)
  2. Ball carriers, linebackers, and TEs (FB, ILB, OLB, RB, and TE)
  3. WRs and defensive backs (CB, FS, SS, and WR)
  4. QB.

It is suggested that each of these 4 groups perform a combination of measures from a pool of 4 tests. Thus, although 4 distinct groups are suggested, only 4 tests need to be considered. The 4 recommended tests are deemed to measure the attributes identified in Table 1. Following are descriptions of these tests.

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36.6-m SPRINT

Similar to the 36.6-m sprint test performed within the current combine battery, players run 36.6 m as fast as possible. Split times are recorded at 4.6, 9.1, 18.3, and 27.4 m. From the 5 times recorded, measures of acceleration over 4.6, 9.1, and 18.3 m are available, and a measure of maximum speed can be determined via a “flying” 18.3-m time. By subtracting the time taken to complete the first 18.3 m from the time taken to complete the entire 36.6 m, a measure of maximum speed, unaffected by acceleration, is possible. As a sample not discriminated by position, the relationships among the 9.1-, 18.3-, and 36.6-m sprint times have been indicated to be very strong (r = 0.900–0.967) in NFL draftees (21). When divided into semihomogenous groups of positions, the strength of the correlations are reduced (r = 0.458–0.926), with many being of a value indicating independent motor skills (22). Coefficients of variation (r2) of <0.50 (i.e., shared common variance < 50%) indicate motor skills of an independent nature (26), and thus, depending on group of positions, current evidence suggests both independent and dependent relationships (22).

Although the measurement of motor skills not independent of one another is inefficient (22), rationale for the inclusion of 4 split times exists. Because of the nature of American football in which “getting off the ball” is so greatly emphasized (4), a measure of first-step quickness (4.6-m sprint) is deemed essential. The 9.1-m split time is necessary to calculate acceleration momentum (described below) of more than 9.1 m from a stationary start. The 18.3-m split is necessary to calculate maximum speed using the flying 18.3-m sprint described above. The 27.4-m split time is necessary to calculate maximum velocity momentum (described below), and finally, the 36.6-m time is necessary to derive the measure of maximum speed. Thus, although likely that some of these split times are strongly associated with one another in certain positions, all splits serve a purpose. Furthermore, testing time is not increased with the addition of timing gates, and additional cost is negligible.

Post hoc analysis of sprint interval times allows for the calculation of various characteristics over varying distances at various “flying” velocities. This allows for unaffected (or less affected) measures of independent characteristics. For example, calculation of sprinting momentum is possible. Sprint momentum is the quantity of motion an object contains and may be calculated by multiplying the velocity of an object by its mass. An athlete with greater mass, running at an equal velocity to that of a lighter athlete, possesses more momentum. Calculations of sprint momentum have been found to differentiate between players of varying skill in the sport of Rugby League (1). In a collision sport, such as American football, the point of contact will be dominated by those who can generate greater amounts of sprinting momentum. Positions that play predominantly in and around the line of scrimmage would benefit from the ability to generate a greater amount of momentum in the acceleration phase of sprinting. Similarly, WRs able to generate greater acceleration momentum would have an advantage in combating press coverage situations. Defensive back (CB, FS, and SS), WR and special team positions would likely benefit from enhanced maximal velocity momentum when playing in an open space where collisions often occur at greater sprinting velocities.

With the exception of linemen and QBs, it is recommended that all positions perform the 36.6-m sprint with split times recorded, as described above. It is recommended that the lineman and QB positions perform an 18.3-m sprint with a split time recorded at 4.6 and 9.1 m. A measure of speed of more than 36.6 m is deemed unnecessary in linemen and QBs. It is recommended that a measure of acceleration momentum (0–9.1 m) be calculated for all positions other than QB (i.e., groups 1–3) and that maximal velocity momentum (27.4–36.6 m) be derived for groups 2 and 3 (i.e., linemen and QBs exempt). For clarity, momentum is calculated by multiplying body mass by sprinting velocity. The stance from which each position performs these linear sprints depends on position-specific stances from which plays are commonly initiated. Specifically, it is recommended that the lineman, TE, and FB positions perform the test from a 3-point stance, whereas CBs, FSs, ILBs, OLBs, QBs RBs, SSs, and WRs start from a 2-point stance.

To assess linear sprint performance over the suggested distances, timing lights with electronic timers are placed at the start line, 4.6, 18.3, 27.4, and 36.6 m. Players run the required distance from the position-specific stance as fast as possible. Initiation of the sprint is by an auditory tone emitted by commercially available testing gates. The time between emitted tone and sprint start is recorded as a measure of reaction time. Reaction time is indicative of a player's ability to “get off the ball” and is arguably one of the most highly desirable qualities in most, if not all, positions. Each player performs 2 sprints separated by a minimum of 5 minutes. It has previously been suggested that in college American football players, rest intervals of 5 minutes are sufficient to recover between sprints of similar distances (4). The best times achieved at each distance are recorded for analysis. Thus, the 36.6-m sprint test provides various measures of sprint ability including reaction time to the start of a play.

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ISOMETRIC MID-THIGH PULL

Maximal strength has been shown to differentiate between players of varying performance levels in American football (7). Performing 1 repetition maximum strength testing during the NFL combine is an impractical use of time and logistically difficult. To assess lower-body strength output, a test that is both easy to administer and an efficient use of time must be selected. The isometric mid-thigh pull exercise has been shown to correlate well with 1 repetition maximum testing in American college football players (15). This test has been shown to be highly reliable and reflective of strength characteristics in a variety of lower-body tests (10,14,16,18). The above-mentioned characteristics of the isometric mid-thigh pull make it well suited for use in the current combine setting as a measure of lower-body maximal strength.

As previously described (14), it is recommended that the isometric mid-thigh pull exercise test be performed with an athlete pulling on an immovable object. This can be facilitated while standing on a force plate in a power rack, with the bar restricted by pins. The athlete is instructed to pull as hard and fast as possible for 5 seconds. The bar height is set so that the athlete's knee angle is 130° during the test. Peak force and rate of force development data are collected using the force plate. As research suggests that the rate of force development is a unique strength quality, as compared with maximal strength, it is recommended that it be acquired (14,16,18). Such data may provide NFL player personnel with insight into the “speed” of a hit/tackle in addition to the “strength” of a hit/tackle. It is recommended that three 5-second trials be conducted with 3-minute rest intervals separating trials (14,16). The highest peak force and rate of force development values obtained should be recorded for analysis.

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BENCH PRESS

Similar to the current battery, the bench press for maximum repetitions is recommended as a measure of upper body strength. To better determine maximal upper-body strength, it is suggested different absolute loads are available for each of the 2 groups performing this test. Specifically, it is suggested that loads of 170.1 and be 147.4 kg be implemented for the linemen and ball carrier/linebacker/TE groups, respectively. The recommended loads are based on previous research in which it was determined that the average number of repetitions completed using 102.1 kg ranged from 24.79 to 29.14 and 21.44 to 24.05 in the linemen and ball carrier/linebacker/TE groups, respectively (21). It is considered that the prescribed intensities will, in most cases, prevent greater than 10 repetitions being completed and thereby provide a better indication of maximal upper-body strength.

As described in previous research, the method by which the bench press test is performed at the NFL combine is likely adequate (13,25). Attempts should be made to ensure proper technique (feet flat to ground; buttocks, back and head flat to bench; full range of motion), and a certified strength and conditioning specialist should be present to verify countable repetitions. Because of the relatively high intensity of the lift, a certified strength and conditioning specialist should provide “spotting” to allow for repetitions to failure.

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VERTICAL JUMP

As previously discussed, vertical jump height ability is likely not an attribute particularly useful to many positions making up an NFL roster. The inclusion of this test across positions is a function of the outcome measures, which may be acquired from a force plate. Rather than vertical jump height being of the greatest interest, other data such as rate of force development, acceleration, velocity, and power output may prove more useful for the purposes of player selection. Much debate exists as to which of these measures may be most elucidating. As force plates commonly record multiple outcome measures for each jump, rather than recommend a single measure (e.g., power output), it is recommended that before data collection, consideration be given to which measure(s) is deemed of interest. It is possible measures of interest will vary across groups or positions.

The vertical jump should be performed from a force plate, which is flush with a surface large enough to allow the player to jump for maximal height with confidence. This can be achieved by embedding the force plate into the floor or using a custom platform into which the force plate is placed. Using a countermovement with arm swing, players jump for maximal height. Three jumps should be completed. The best outcome(s) of the predetermined measure(s) of interest should be recorded. For positions in which vertical jump height ability is of little interest, it is recommended that measure(s) more directly relevant (e.g., power output) be analyzed.

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AGILITY

After much consideration and debate, a test of agility has not been included in the recommended battery. This is not because agility is felt to be unimportant. On the contrary, agility is deemed of great importance across positions for success in American football. As such, it is imperative that agility be accurately evaluated. Following is a discussion providing the rationale for the exclusion of a test of agility from the recommended battery.

Recently, what constitutes agility in sport has been questioned. Agility has been defined in the past as any movement that involves a rapid change of direction. Recently, it has been suggested that a more accurate description of agility involves change of direction in response to a sport-specific situation or stimulus (23). Agility can therefore be interpreted as having both a physical and cognitive component. The physical component of agility can be defined as change-of-direction speed and can be influenced by physical factors, such as technique, linear sprint speed, and leg muscle properties (23,28,29). The cognitive components of agility include a player's ability to perceive various sport-specific stimuli and the ability to react and execute movement according to those stimuli. Inclusion of a perceptual cognitive aspect of agility complicates the assessment of this attribute. As change-of-direction speed is a unique property that poorly predicts agility ability (24), it is not acceptable to test players using predetermined patterns to assess a player's agility ability.

A number of tests of reactive agility have recently been described in the literature (3,6,8,19,24,27,30). These tests use various stimuli to induce changes in movement direction and speed. The stimulus is initiated by a tester using predetermined movement patterns in acting as either an offensive or a defensive player, or by commercial timing gates with flashing lights designed to flash randomly to stimulate movement decisions. In a number of these tests, not only is total movement time and response accuracy being recorded, but based on post hoc video analysis, decision time is also being determined. In the development of these tests, research has often examined the relationships between reactive agility ability and change-of-direction ability and linear speed in attempts to determine shared common variance (3,9,19,27,29). Research indicates that reactive agility ability is a unique attribute (6,9,24). Additionally, tests of reactive agility ability have been shown to be more successful in differentiating between players of varying skill level when compared with tests of change-of-direction ability and linear sprint speed (6,8,9,24).

Although arguably superior to the currently implemented change-of direction tests at the NFL combine, the above-mentioned reactive agility tests are not without limitations. These tests are commonly very laborious and difficult to efficiently implement into test batteries. As many of these tests require multiple trials and randomized ordering of the agility stimulus, testing of large groups of athletes is a lengthy procedure. Also, as many of these tests require a tester to repeatedly administer accurate and distinct agility stimuli movements, the larger the testing group, the more likely mistakes by the tester because of fatigue could lead to decreased reliability in the data collected. Substitution of nonfatigued testers is problematic for consistency of stimuli. Furthermore, the majority of the reactive agility tests developed to date have been done so with sports in mind, whereby players perform offensively and defensively. The unique nature of American football in which players belong to either an offensive or defensive team (special teams exempted) requires special consideration. A standardized test may be inappropriate. Rather, depending on position, unique agility tests may be warranted.

Unfortunately, as a result of their unique nature, it is logistically difficult to implement tests of reactive agility into test batteries. To accurately evaluate agility, group-specific reactive tests would likely be necessary. To eliminate the possibility of players predicting “cut” direction, multiple randomized trials would be necessary for each player. Furthermore, subsequent video analysis would be time consuming. Despite the above-described limitations, although impractical, the inclusion of such a test into the combine setting would be of benefit. Thus, rather than collecting data using “practical” tests measuring attributes of questionable importance (e.g., change-of-direction ability tests currently used) or suggesting “unfeasible” sophisticated tests with little chance of implementation, it is recommended that agility assessment be made by scouts and coaches with a video of game situations and through the observation of position-specific drills that are conducted at the combine.

A summary of tests, measured attributes, and required equipment by which to perform these tests is presented in Table 2. The tests recommended above have been devised with practicality, feasibility, and cost in mind. Without question, some of the equipment required is more expensive than that currently used. At first glance, 4 distinct groups may seem onerous and time consuming. Although a detailed feasibility study including a cost analysis is beyond the scope of this article, following is a brief discussion regarding the logistics of implementing the recommended test battery.

Table 2

Table 2

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LOGISTICS

Approximately 330 athletes are invited to the NFL combine annually (20). As per the above-described groupings based on the required physical attribute commonalities and the relative positional makeup of combine draftee pools previously presented (20), it is determined that the annual sizes of the 4 semihomogenous groups (assuming 330 invitees and a similar invitee/draftee proportion across positions) would be approximately 110, 92, 110, and 17 for the linemen, ball carrier/linebacker/TE, WR/defensive back, and QB groups, respectively. Of course, this will vary annually depending on the college player pool. Before a brief discussion regarding the feasibility of the recommended battery, comment on the manner in which the battery could be conducted would seem prudent. The following discussion will focus on methods by which to efficiently complete testing.

Currently, physical testing would appear to be held over 4 days with each day being devoted to particular positions (17). The bench press test is generally conducted on the day before the other physical tests. Given that testing occurs over 4 days, and the consistency of size of the aforementioned 4 groups (QB group excepted), it is suggested that each group be tested on a separate day. Furthermore, as the WR/defensive back and QB groups are not required to perform the maximal strength testing, it is suggested that these groups are tested on days 3 and 4. As such, the equipment necessary for strength measurement can be removed after the second day of testing. Thus, for days 1 and 2, 4 testing stations would be necessary, whereas for days 3 and 4, only 2 stations would be required.

In order that best performances are attained, the sequence in which the measures are performed is important, as is recovery time between trials and tests. As the maximal strength measures are fatiguing, it is suggested that these measures are performed later in the battery. This is particularly important with respect to the mid-thigh pull exercise, which could significantly confound performance in the other tests in which the lower body is predominantly engaged. With respect to the other 2 tests that are arguably less fatiguing, but allow for multiple trials, care should be taken to allow for complete recovery between the trials. With the exception of the QB group, given that subgroups of 20–30 participants will likely be engaged at each of the 2 stations (except day 3 in which subgroups will be larger as a result of the reduction in testing stations), sufficient rest between trials should not be an issue. Assuming track lanes for linear sprinting and force plates for vertical jumping are limited (i.e., 2–4), rotation of participants will allow for adequate recovery.

Without a detailed comparison of the time requirements associated with the current, as compared with the proposed, battery, it is difficult to confidently comment on any time advantages, which the recommended battery may hold. Nonetheless, as 4 tests makeup the recommended battery, as compared with 6 in the current battery, and as days 3 and 4 involve only 2 tests, it is possible that the testing time requirements associated with the proposed battery are somewhat less than those associated with the currently implemented battery. Conversely, it is possible that the time required preparing the equipment necessary for the recommended battery and post hoc data analysis is somewhat greater. Arguably, the preparation of squat racks and force plates for the mid-thigh pull and force plates for the vertical jump make preparation of the recommended battery more labor intensive. It is also likely that a greater total amount of data be acquired under the recommended battery, and thus, greater time for analysis may be required. Furthermore, it is acknowledged that although time is saved by not including a measure of agility, time must still be allotted for the evaluation of agility using the recommended methods.

Any potential “efficiency” advantages associated with the recommended battery and related cost advantages (e.g., reduced labor costs) are likely offset by increased equipment costs. Although the equipment costs associated with the 36.6-m sprint and bench press tests are likely similar between batteries (perhaps slightly greater under the recommended battery because of the need for additional timing gates), the equipment required for the mid-thigh pull and vertical jump represent increased capital expenditure. Whether the increase in equipment cost is wholly or partially offset by potential reductions in labor costs is arguably of little importance. Any difference (positive or negative) in total resource allocation associated with the recommended battery would be of such little value in relation to the total cost of holding the combine to relegate such difference irrelevant.

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CONCLUSION

The current NFL combine test battery is in need of revision. The rationale underlying the implementation of some of the tests included is not obvious. Without exception, those tests that are relevant can be improved upon. Furthermore, there is arguable redundancy in motor skill measured. Finally, given that very different skill sets are required for success depending on position, it is puzzling that with little exception, all positions perform a similar series of tests. It is unnecessary and inefficient to conduct testing designed to measure physical attributes, which are of little importance to success at specific positions. The same is true with respect to measuring motor skills not independent of one another.

Determination of the skills necessary for positional success revealed that commonalities do exist among positions making up American football rosters. Furthermore, determination of selected measurable underlying physical attributes necessary for success led to the development of 4 semihomogenous groups of positions. Four tests have been devised and recommended as a battery to replace the currently implemented NFL combine battery. It is suggested that the logistics and cost of the recommended battery make it feasible as an alternative for implementation within the current combine setting.

Agility has received much attention of late. Personal experience and review of the literature resulted in the exclusion of a test of agility from the recommended battery. A valid, reliable, and practical tool by which to measure reactive agility in American football players is needed. Attempts have been made to devise such a tool in a number of sports including netball, Australian Rules football, rugby league, and rugby union (3,6,8,19,24,27,30). Limitations exist with respect to all currently available reactive agility tests. It is recommended that a future research direction be the determination of a valid, reliable, and practical field test(s) of reactive agility designed with American football in mind.

It is important to note that the currently presented evaluation of the NFL combine is narrative in nature and represents examination of only a portion of the assessments conducted at the combine. The opinions presented in this article should not be interpreted to reflect on any portion of the combine other than that portion examined (i.e., the physical test battery). Comment on various other testing (e.g., psychological, behavioral) is beyond the scope of this article. It is not the intent of the authors to question the worth of the NFL combine or draft selection decisions. Such decisions are surely based on much more information than that provided through the combine physical test battery. Nonetheless, as discussed above, it is the belief of the authors that better and more useful physical attribute information may be collected at the combine by revising the currently implemented physical test battery. In-depth analysis of the combine, or portions of the combine, would likely contribute to a more comprehensive evaluation. Such contributions are welcomed and would hopefully add to a robust debate regarding not only the NFL combine but also physical test batteries in general. The present examination and subsequent recommendations represent a single framework based on a critical evaluation.

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PRACTICAL APPLICATIONS

Coaches and practitioners involved in the construction of test batteries for either the purpose of player selection or monitoring of training adaptation would be well-advised to adopt a systematic process similar to that used in the present research. Specifically, consideration of positional skill requirements should be the initial phase of battery development. This is especially relevant when devising batteries by which to test players involved in sports such as American football or rugby codes in which positional skill requirements vary considerably.

Admittedly, resources restrict the number of tests that may be included in a battery and compromises may be necessary. Upon identification of the attributes of interest, care should be taken to devise strategies deemed best able to most directly measure those attributes. Finally, care should be taken to ensure that independent motor skills are measured.

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REFERENCES

1. Baker DG, Newton RU. Comparison of lower body strength, power, acceleration, speed, agility and sprint momentum to describe and compare playing rank among professional rugby league players. J Strength Cond Res 22: 153–158, 2008.
2. Barker M, Wyatt TJ, Johnson RL, Stone MH, O'Bryant HS, Poe C, Kent M. Performance factors, psychological assessment, physical characteristics and football playing ability. J Strength Cond Res 7: 224–233, 1993.
3. Bradshaw RJ, Young WB, Russell A, Burge P. Comparison of offensive agility techniques in Australian Rules football. J Sci Med Sport 2010. doi:10.1016/j.jsama.2010.06.022.
4. Brechue WF, Mayhew JL, Piper FC. Characteristics of sprint performance in college football players. J Strength Cond Res 24: 1169–1178, 2010.
5. Cronin JB, Hansen KT. Strength and power predictors of sports speed. J Strength Cond Res 19: 349–357, 2005.
6. Farrow D, Young W, Bruce L. The development of a test of reactive agility for netball: A new methodology. J Sci Med Sport 8: 52–60, 2005.
7. Fry AC, Kraemer WJ. Physical performance characteristics of American football players. J Appl Sport Sci Res 5: 126–139, 1991.
8. Gabbett T, Benton D. Reactive agility of rugby league players. J Sci Med Sport 12: 212–214, 2009.
9. Gabbett TJ, Kelley JN, Sheppard JM. Speed, change of direction speed, and reactive agility of rugby league players. J Strength Cond Res 22: 174–181, 2008.
10. Haff GG, Stone M, O'Bryant HS, Harman E, Dinan C, Johnson R, Han KH. Force time dependant characteristics of dynamic and isometric muscle actions. J Strength Cond Res 11: 269–272, 1997.
11. Hoffman JR, Ratamess NA, Klatt M, Faigenbaum AD, Kang J. Do bilateral power deficits influence direction-specific movement patterns? Res Sport Med 15: 125–132, 2007.
12. Mayhew JL, Ware JS, Bemben MG, Wilt B, Ward TE, Farris B, Juraszek J, Slovak JP. The NFL-225 test as a measure of bench press strength in college football players. J Strength Cond Res 13: 6–11, 2003.
13. McGee KJ, Burkett LN. The National Football League combine: A reliable predictor of draft status? J Strength Cond Res 17: 130–134, 1999.
14. McGuigan MR, Newton MJ, Winchester JB. Use of isometric testing in soccer players. J Aust Strength Cond 16: 11–14, 2008.
15. McGuigan MR, Winchester JB. The relationship between isometric and dynamic strength in college football players. J Sport Sci Med 7: 101–105, 2008.
16. McGuigan MR, Winchester JB, Erickson T. The importance of isometric maximum strength in college wrestlers. J Sport Sci Med: 108–113, 2006.
17. NFL.com. Combine. Available at: http://www.nfl.com/combine. Accessed: September 2, 2010.
18. Nuzzo JL, McBride JM, Cormie P, McCaulley GO. Relationship between countermovement jump performance and multijoint isometric and dynamic tests of strength. J Strength Cond Res 22: 699–707, 2008.
19. Oliver JL, Meyers RW. Reliability and generality of measures of acceleration, planned agility, and reactive agility. Int J Sport Physiol Perform 4: 345–354, 2009.
20. Robbins DW. The NFL combine: Does normalized data better predict performance in the NFL draft? J Strength Cond Res 24: 2888–2899, 2010.
21. Robbins DW. Positional physical characteristics of players drafted into the National Football League. J Strength Cond Res 25: 2661–2667, 2011.
22. Robbins DW, Young WB. Positional relationships between various sprint and jump abilities in elite American football players. J Strength Cond Res 26: 388–397, 2012.
23. Sheppard JM, Young WB. Agility literature review: Classifications, training and testing. J Sports Sci 24: 919–932, 2006.
24. Sheppard JM, Young WB, Doyle TA, Sheppard TA, Newton RU. An evaluation of a new test of reactive agility, and its relationship to sprint speed and change of direction speed. J Sci Med Sport 9: 342–349, 2006.
25. Sierer SB, Battaglini CL, Mihalik JP, Shields EW. The National Football League combine: Performance differences between drafted and nondrafted players entering the 2004 and 2005 drafts. J Strength Cond Res 22: 6–12, 2008.
26. Thomas JR, Nelson JK. Research Methods in Physical Activity. Champaign, IL: Human Kinetics, 2001.
27. Wheeler KW, Sayers MGL. Modification of agility running technique in reaction to a defender in rugby union. J Sport Sci Med 9: 445–451, 2010.
28. Young W, Farrow D. A review of agility: Practical applications for strength and conditioning. Strength Cond J 28(5): 24–29, 2006.
29. Young WB, James R, Montgomery I. Is muscle power related to running speed with changes of direction? J Sports Med Phys Fitness 42: 282–288, 2002.
30. Young WB, Wiley B. Analysis of reactive agility field test. J Sci Med Sport 13: 376–378, 2010.
Keywords:

NFL combine; performance testing; American football; position; sprint; agility; strength

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