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Journal of Strength and Conditioning Research, 1999, 13(2), 130–134q 1999 National Strength & Conditioning Association

The NFL-225 Test as a Measure of Bench PressStrength in College Football Players

JERRY L. MAYHEW,1 JOHN S. WARE,2 MICHAEL G. BEMBEN,3 BILL WILT,4TOM E. WARD,5 BILL FARRIS,3 JOE JURASZEK,6 AND JOHN P. SLOVAK5

1Department of Exercise Science, Truman State University, Kirksville, Missouri 63501; 2Athletic Department,Truman State University, Kirksville, Missouri 63501; 3Department of Health and Sport Sciences, University ofOklahoma, Norman, Oklahoma 73019; 4Athletic Department, Western Illinois University, Macomb, Illinois61455; 5Department of Physical Education, Texas A&M at Commerce, Commerce, Texas 75429; 6AthleticDepartment, Oklahoma University, Norman, Oklahoma 73019.

ABSTRACTTo assess the efficacy of the NFL-225 test to evaluate upper-body strength in football players, 142 college players (69 Di-vision IAA and 73 Division II) were measured at the conclu-sion of their off-season resistance training program for 1 rep-etition maximum (1 RM) bench press and repetitions to fa-tigue with 225 lb. A validation sample of players (n 5 114)was randomly selected to develop a prediction equation thatwas significantly correlated with 1 RM (r 5 0.96) and al-lowed reasonably accurate predictions (SEE 5 14.1 lb). Theremaining 28 players served as a cross-validation sample thatproduced a high correlation (r 5 0.96) and a nonsignificantdifference (t 5 0.46) between predicted and actual 1 RM.Sixty-eight percent of the cross-validation sample had pre-dicted 1 RM values within 610 lb of their actual 1 RM per-formance. Therefore, muscular endurance repetitions with anabsolute load of 225 lb can be used to predict 1 RM benchpress strength in college football players, although the errorin prediction increases when endurance performance ex-ceeds 10 repetitions.

Key words: strength prediction, muscular endurance

Reference Data: Mayhew, J.L., J.S. Ware, M.G. Bemben,B. Wilt, T.E. Ward, B. Farris, J. Juraszek, and J.P. Slovak.The NFL-225 test as a measure of bench press strengthin college football players. J. Strength Cond. Res. 13(2):130–134. 1999.

Introduction

The most often used technique for measuringstrength is the 1 repetition maximum (1 RM) pro-

cedure, which can require additional time and mentalpreparation during a training program. The use ofmuscular endurance repetitions with a ,1 RM load toestimate maximal strength has gained popularity inrecent years. Such a procedure uses either an absoluteor a relative load to evaluate muscular endurance un-

der the supposition that muscular endurance is relatedto strength.

A relative muscular endurance load represents anamount of weight typically based on some proportionof the 1 RM (2, 4, 14, 15, 24) or body weight (13). Thecorrelations between 1 RM strength and the numberof repetitions completed with a relative load are typ-ically small in magnitude, ranging from r 5 20.40 to0.44 (4, 5, 8, 14, 23, 24). An absolute muscular endur-ance load represents a constant amount of weight forevery individual being evaluated, with the amount de-pendant on several factors. Some of these factors in-clude occupational demands (10), the average of agroup performance (24), or a fixed amount (8, 12, 22).The correlations between 1 RM strength and the num-ber of repetitions completed with absolute loads areusually high, ranging from r 5 0.74 to 0.93 (6, 8, 12,24), indicating those with greater strength levels havegreater absolute muscular endurance.

One approach to estimate strength using an ab-solute load of 225 lb has gained favor among someNational Football League (NFL) teams. The NFL-225test requires a player to complete as many repetitionsas possible in the bench press with a 225-lb barbell.Although no statistical evaluation of this test on NFLplayers has been reported, Chapman et al. (6) recentlyfound a correlation of 0.96 between NFL-225 repeti-tions and 1 RM bench press in Division II players. Theauthors suggest that the NFL-225 test may be a validpredictor of 1 RM bench press for most college players,but they caution that its applicability may not be uni-form for all players. If there is a strong relationshipbetween repetitions completed with an absolute loadand 1 RM strength, the NFL-225 test could be used toestimate strength with reasonable accuracy, thus sav-ing training time and avoiding exposure of the playerto any potential danger from handling excessively

Strength Prediction 131

heavy loads during maximal attempts. Such informa-tion would be of value to college coaches, athletictrainers, and conditioning specialists in evaluatingstrength and planning resistance training programs.The purpose of this study was to determine the rela-tionship between repetitions completed with an ab-solute load of 225 lb and the 1 RM bench press incollege football players at different levels of competi-tion.

MethodsSubjectsOne hundred forty-two college football players from 3NCAA universities volunteered to participate. The val-idation sample was composed of 52 Division IAAplayers, 41 Division II regular players, and 21 DivisionII red-shirt freshmen. A cross-validation sample wasrandomly selected from the original sample and wascomposed of 17 Division IAA players, 7 Division IIregular players, and 4 Division II red-shirt players.This represented a similar percentage makeup as thevalidation sample.

The players were measured at the conclusion oftheir winter conditioning period after resistance train-ing for a minimum of 8 weeks. Each university had itsown specific resistance training program designed toenhance football playing ability. While these programsmay have differed slightly, each emphasized heavy re-sistance and low repetitions in core exercises, such asbench press, squat, and push press centered around amodified periodization approach. Various supplemen-tal exercises, such as upright rowing, lat pulls, armcurls, incline presses (dumbbell and/or barbell),dumbbell lateral raises, deadlifts, leg presses, and legcurls, were also used.

1 RM Bench PressThe 1 RM bench press procedure followed the stan-dard ‘‘touch-and-go’’ protocol in which the bar wasrequired to touch the chest before being pressed to fullarms’ extension (26). During testing each player wasallowed to warm up according to personal preferencesusing light weights of approximately 50 to 75% of es-timated 1 RM. Although no record was kept, eachplayer was encouraged to reach his 1 RM within 4 to5 attempts. A minimum of 5 minutes’ rest was givenbetween attempts. Standard Olympic bar and plateswere used for all lifts, and the player used a grip thatwas slightly wider (approximately 20–30 cm) thanshoulder width. The reliability of this method has beenreported to be greater than r 5 0.98 (12, 22).

Repetition TestWithin 1 week before or after completing the 1 RMtest, each player was required to perform as many rep-etitions as possible using a 225-lb barbell. Followingindividual warm-ups, the player grasped the bar at the

same position used during the 1 RM procedure. Thebar was lowered slowly each time and required totouch the chest without bouncing, and the arms wererequired to extend fully on each repetition. No morethan a 2-second rest was allowed during an individualattempt of the repetition test. The test was terminatedwhen the subject could not complete a repetition withproper form. The reliability of similar muscular en-durance protocols ranges from r 5 0.80 (19) to r 50.97 (12, 22).

Statistical AnalysisMeans and SEs were computed for all variables. One-way analysis of variance was used to evaluate differ-ences in the validation sample among the 3 groups,with Tukey’s honestly significant difference used forpost hoc comparisons where significance was noted.Pearson correlation coefficients were used to deter-mine the relationships among the variables. Linear re-gression was used to generate a prediction equationon the validation group using repetitions to estimate1 RM bench press. The predicted 1 RM values werecompared with actual bench press performance in thecross-validation group using a Pearson correlation andpaired t-test.

Results

Table 1 illustrates the physical and performance char-acteristics of the validation group for the 3 levels ofplayers. The only difference among the groups was forage, with the Division II red-shirt players being sig-nificantly younger than the other players.

Correlations among the variables are shown in Ta-ble 2. Body weight was moderately but significantlyrelated to 1 RM and negatively related to %1 RM (225lb/1RM 3 100). The greater the %1 RM representedby the 225-lb load, the fewer repetitions the player wasable to complete. Repetitions completed with an ab-solute load of 225 lb were highly correlated with 1 RMbench press (r 5 0.96) and produced the following lin-ear prediction equation:

1 RM (lb) 5 226.7 1 7.1 (repetitions at 225 lb). (1)

The SE of estimate for this equation was 14.1 lb.The error was smaller when fewer than 10 repetitionswere completed (SEE 5 11.4 lb) than when more than10 repetitions (SEE 5 17.1 lb) were completed (Figure1).

The cross-validation sample was not significantlydifferent from the original sample on any of the phys-ical or performance variables (Table 3). When Equation1 was applied to the cross-validation sample, the pre-dicted 1 RM bench press was highly correlated with(r 5 0.96) and not significantly different from (t 50.46) the actual 1 RM. The predicted 1 RM bench pressrepresented an average overestimation in this group of

132 Mayhew, Ware, Bemben, Wilt, Ward, Farris, Juraszek, and Slovak

Table 1. Means and standard deviations for physical and performance characteristics of college football players (n 5 150).

Variable†Division IAA

(n 5 52)Division II(n 5 41)

Division IIred shirts(n 5 21)

Composite(n 5 114) F ratio

Age (y)Height (in.)Weight (lb)1 RM bench press (lb)Repetitions at 225 lb1 RM/lb%1 RM

20.9 6 1.772.6 6 2.6

222.3 6 39.9308.9 6 53.211.8 6 7.21.41 6 0.2174.9 6 12.4

20.1 6 1.072.5 6 1.0

224.5 6 34.8297.2 6 37.0

9.9 6 5.41.34 6 0.2076.9 6 9.8

20.0 6 1.571.0 6 1.1

227.0 6 34.3292.9 6 50.0

9.4 6 6.01.30 6 0.1878.9 6 12.9

20.4 6 1.472.3 6 2.7

224.0 6 36.8302.2 6 45.610.6 6 6.41.36 6 0.2076.3 6 11.6

4.37*2.981.181.161.472.620.97

* F 5 3.00 is significant at p , 0.05.† 1 RM 5 1 repetition maximum.

Table 2. Correlation of selected variables with 1 RM benchpress strength in college football players (n 5 114).*

Variable 1 RM 1 RM/lb %1 RM

Age (y)Height (in.)Weight (lb)Repetitions1 RM bench press (lb)1 RM/lb

0.160.150.540.95—

0.41

0.2620.5220.53

0.370.41—

20.1320.1820.5520.9620.9820.40

* r 5 0.21 significant at p , 0.01. 1 RM 5 1 repetitionmaximum.

1.1 lb (SD 5 12.5 lb) compared with the actual 1 RM.Twenty-two (78.6%) of the predicted 1 RM values fellwithin 61 SEE of the actual 1 RM. Furthermore, 19players (67.9%) had predicted 1 RM values within 610lb of their actual 1 RM performance. The 95% confi-dence interval on the difference scores (i.e., predicted1 RM – actual 1 RM) indicated that 26 (92.9%) of thepredicted 1 RM values were between 23.6 lb below to25.8 lb above their actual 1 RM (Figure 2).

DiscussionThe current findings indicate that muscular endurancerepetitions using an absolute load of 225 lb can beused to estimate 1 RM bench press strength with rea-sonable accuracy in highly motivated, resistance-trained football players. The accuracy of the NFL-225equation improves as the number of repetitions com-pleted decreases below 10. On players in the cross-validation group who completed 10 or fewer repeti-tions (n 5 19), the difference between predicted andactual 1 RM produced an average underestimation of0.4 lb (SD 5 12.2 lb), with a 95% confidence intervalon the average difference ranging from 6.3 lb below to5.5 lb above actual 1 RM values. For the players whocompleted more than 10 repetitions (n 5 9), the dif-

ference between predicted and actual 1 RM producedan average overestimation of 4.2 lb, but the SD in-creased to 13.5 lb. The 95% confidence interval on thedifference ranged from 6.1 lb below and 14.5 lb aboveactual 1 RM values. These findings agreed with Chap-man et al. (6), who reported a better prediction withfewer than 10 repetitions (r 5 0.92) than with morethan 10 repetitions (r 5 0.87) using the NFL-225 test.However, since 67.9% of the cross-validation playershad their 1 RM accurately predicted within 10 lb oftheir actual 1 RM and only 10.7% had an error greaterthan 20 lb, the NFL-225 test appears to be an accept-able technique for determining strength levels for mostcollege football players. A low but significant negativecorrelation (r 5 20.28, p , 0.05) between actual 1 RMand the difference between predicted and actual 1 RMvalues indicated that the NFL-225 equation tends toslightly overestimate at the lower end and slightly un-derestimate at the upper end of the strength continu-um. For actual 1 RM performances below 300 lb, theequation tended to overestimate actual bench press byan average of 1.3 lb (SD 5 11.7 lb), while for 1 RMperformances over 300 lb, the equation tended to un-derestimate by 0.25 lb (SD 5 16.0 lb). The 95% confi-dence interval on the average difference between pre-dicted and actual 1 RM for those bench pressing 300lb or less ranged from 1.3 lb below to 3.9 lb aboveactual 1 RM values. For those players bench pressingmore than 300 lb, the 95% confidence interval on theaverage difference between predicted and actual 1 RMranged from 4.3 lb below to 3.8 lb above actual 1 RMvalues.

Several previous studies have indicated that fewerrepetitions to fatigue may be more accurate than morerepetitions for predicting 1 RM (1, 17, 19, 21, 26). In-deed, our results concur that performing fewer than10 repetitions to fatigue may offer a better prediction(i.e., less error). Typically, the higher number of repe-titions causes a significant overprediction of 1 RMbench press of approximately 2–3% (7, 17). In the cur-

Strength Prediction 133

Figure 1. Comparison between repetitions with 225 lbsand 1 repetition maximum bench press in college footballplayers (n 5 114). A solid line indicates the regression line;a dashed line indicates the SE line.

Table 3. Comparison between validation and cross-valida-tion groups.*

Validationsample

Mean SD

Cross-valida-tion sample

Mean SDVariable (n 5 114) (n 5 28) t

Age (y)Height (in.)Weight (lb)1 RM bench press (lb)Repetitions1 RM/lb%1 RM

20.472.3

224.0301.810.61.36

76.3

1.52.7

36.847.46.40.20

11.6

20.472.6

217.3291.8

9.31.36

79.0

1.53.0

32.146.76.50.20

12.2

0.000.600.881.000.970.001.06

* t 5 1.96 significant at p , 0.05. 1 RM 5 1 repetitionmaximum; %1 RM 5 225 lb/1 RM 3 100.

Figure 2. Bland-Altman plot between the average of thepredicted and actual 1 repetition maximum (1 RM) benchpresses and the difference between predicted and actual 1RM values in the cross-validation group (n 5 28). A solidline indicates the mean difference between the predicted 1RM and the actual 1 RM; a dashed line indicates the 95%confidence interval on the difference.

rent subjects, however, the higher number of repeti-tions (.10) produced an overestimation of only 0.5%(SD 5 4.9%), which was comparable to the 0.2% (SD5 4.1%) noted for the lower number of repetitions(,10). This problem may be a drawback to considerwhen using an absolute load for predicting maximalstrength.

If repetitions to fatigue are to be used to estimatemaximal strength, one of the major questions confront-ing the strength and conditioning specialist, coach, orathlete is how much weight to use when performingthe test to get the most accurate prediction. Most ofthe recent investigations to predict 1 RM from repeti-tions have used a load relative to the individual’s 1

RM. These studies indicate that loads between 80 and90% of 1 RM appear to produce the best results (1, 20,22, 27). In the current study, players performing #10repetitions to fatigue used an average of 84.4% (SD 58.0%) of the 1 RM, whereas players performing .10repetitions used an average of 66.4% (SD 5 6.5%) oftheir 1 RM. To circumvent the problem of performingthe 1 RM, perhaps the submaximal load should be de-termined based on the player’s body mass or fat-freemass. Although this approach is appealing, no criteriafor the appropriate percentage of body mass or fat-freemass have been established because of the wide rangein the strength:body weight ratio often exhibited incollege football players (3, 9, 18).

It is possible that the error associated with pre-dicting 1 RM from repetitions may not go consistentlybelow 15 to 20 lb because of differences in muscle fibertype and training programs. Training programs thatemphasize higher repetitions and/or more sets may bestimulating muscle endurance capacity and size de-velopment more than strength improvement. McGeeet al. (20) noted that 3 sets of 10 repetitions producedgreater squat endurance capacity than a periodizedprogram in which the repetitions per set were reducedas training progressed. Other studies have noted thatresistance training programs using several sets of 10to 12 repetitions have produced significant strengthgains without altering the relative endurance capacityin the bench press at 60% 1 RM (23). The same findingwas noted when relative endurance loads representing

134 Mayhew, Ware, Bemben, Wilt, Ward, Farris, Juraszek, and Slovak

55 to 95% of the %1 RM were used, with approxi-mately the same number of repetitions to fatigue per-formed before and after training (16). Hickson et al.(11) found that muscular endurance capacity in thebench press and squat were related to the percentageof slow-twitch muscle fibers (r 5 0.69 and 0.83, re-spectively), although they also noted that a higher per-centage of slow-twitch muscle fibers did not producegreater adaptation of muscle endurance capacity thanshown in muscle with a higher fast-twitch percentage.

Practical Applications

Repetitions to failure completed with 225 lb can beused to predict 1 RM bench press with reasonable ac-curacy in college football players. The NFL-225 equa-tion developed in the current study predicted approx-imately 68% of the cross-validation players within 610lb of their actual 1 RM bench press. The NFL-225equation may have less predictive accuracy when morethan 10 repetitions are completed. This is usually seenin the heavier players (namely, linemen) who completeunusually high numbers of repetitions (.20). The ten-dency at the higher end of the strength continuum isto slightly underestimate actual strength ability. Thismay not necessarily be a bad feature when designingstrength programs, since it is always easier for an in-dividual to adjust training loads upward to accom-modate his ability than to treat an injury due to ex-cessive muscular stress from loads that are too heavy.

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