Creation of a Criterion-Referenced Military Optimal Performance Challenge [Military Medicine]

ABSTRACT Purpose: To compare an empirical, Army doctrine-based (endurance, strength, mobility, military rele- vant tasks), criterion-referenced, body mass (BM) unbiased Military Optimal Performance Challenge (MOPC) to the Army's Physical Fitness Test (APFT) and thus assisting commanders to determine military readiness. Methods: Militarily-relevant physical assessments were combined to create a composite MOPC score. The MOPC and APFT were administered to 20 male, military subjects during a 2-week period. Data collection included 3-Mile Run, Mobility Test, Upper/Lower Body Strength/Endurance, Simulated Casualty Evacuation Test. The APFT was administered through Army guidelines before MOPC data collection. Results: The APFT was influenced by BM, lean body mass (LBM) (r = -0.44; r2 = 0.20; p= 0.04), whereas MOPC was less impacted (r = 0.21; r2 = 0.04; p= 0.32). Eight subjects, as viewed by %APFT, are "fit for duty" (80.6%); however, all eight subjects' mean score as %MOPC was < 50%. Conclusions: The MOPC offers a robust approach to military readiness and is free of the confounding influence of BM. The MOPC is a unique assessment requiring a multitude of abilities to garner success and may assist in training for functional combat performance skills demanding high work capacities.

INTRODUCTION

The rigors of physical combat in the armed forces are unquestioned. In preparation for combat, current physical training (PT), "best practices" are varied not only for future combat engagements but also for future armed services phys- ical fitness tests. In other words, at times, there is a philoso- phy to "train for the PT test," whereas other service members stay focused on battle-centric PT. All five United States' armed services have some version of a physical fitness test that includes a distance run and timed push-ups (PU) and sit- ups (SU).1 Several challenges exist with the current physical fitness testing models, namely: (1) a BM bias against heavier, not just fatter men and women,2 (2) extensive training for specific tests because promotion and retention are dependent on physical fitness assessment scores, (3) a "no-equipment, field-centric" environment leading to potential assessments being discounted because of equipment requirements, and (4) the belief that physical fitness assessment correlates with demanding military relevant tasks.

The previous statement is supported by the practice of many leaders still inquiring as to the average of one's "unit physical fitness score," when APFT scores and "battle fitness readiness" or actual military performance in competitive selection programs have correlated weakly (r = 0.25).3 Harman et al4 stated since unit leaders are responsible for improving fitness scores of their troops, military units tradi- tionally place the most emphasis in their PT on exercises that raise physical fitness scores. In an extensive review, Harman and Frykman5 concluded distance runs, PU, and SU scores are not potent determinants of physically demanding military tasks. Related to the Army, the current physical fitness tests' (2 minutes of PU and SU and a two-mile run [2MR]) overall intent when designed in the late 1970s/early 1980s was noth- ing more than a baseline fitness test administered and graded for the privilege to wear the uniform (BG J. Anderson (Ret.), personal communication). Unfortunately, some commanders still rely heavily on the comprehensive APFT score (both individual and unit) as a screening method when examining a unit's combat readiness.

In addition, technological advances have led to improve- ments in the soldier's personal body armor (lethality, protec- tion) resulting in potential weight overload. As equipment weight increases, so does the subsequent soldier physiologi- cal demand. The relationship between soldier load and sub- sequent metabolic physiological performance is critical. In our current investigation, our subjects' BM was ^180 lbs (82 kg), and thus conventional loading of 90 to 110 lbs (40.9--50.0 kg) would represent on average over 50% to 60% of the soldier's body weight. Although investigating a proto- type soldier Land Warrior System, we found executing a 10% graded foot march at 3.5 mph wearing ^27 kg of equipment (30% BM; 35% lean body mass [LBM]) represented a work output of ^52% VO2 max, 61% VE max, 89% HR max, and 87% RER max.6 Alt in our laboratory found heavy work output demands, and thus constant rate treadmill foot marching (4.0 mph) with all-purpose, lightweight individual carrying equipment packs of 70% LBM yielded work output of ^58% of one's VO2 max.7 Knapik8 examined heavy loads during a 20-km foot march and determined as load increased, pace decreased. Heart rate was used to determine physiolog- ical demand. Out of respect to the increasing soldier physio- logical demand, more and more PT is incorporating some form of "battle-focused PT," and/or strength and mobility conditioning.9 Armed services have incorporated this con- cept; recently the Marines in 2008, created a second fitness test, the Combat Fitness Test10 that incorporates military skills (casualty evacuation, grenade throw, low crawl, etc.) and other performance-based skills; speed, high intensity conditioning, agility, coordination, strength, and power. The Air Force and Navy have had an active research and dialogue related to fitness assessments and physical readiness.11,12 In addition, Vanderburgh et al13 has proposed a load carriage distance run and PU test that is occupationally relevant and importantly limits the BM bias. Likewise, in our laboratory we have determined a loaded 5K-run test has shown rela- tively high reliability ( p = 0.69) and typical Army fitness measures of PU, SU, and body composition measures of % fat, and LBM fail to explain much variance on the perfor- mance of a modified Pre-Fatigue Simulated Casualty Evacu- ation Test. Still further, a combination of military movement academic grade (obstacle course, rope climbing, gymnastics skills) and 2MR offered the greatest predictive value, how- ever, yielding only ^39% of the Pre-Fatigue Simulated Casu- alty Evacuation Tests variance.14 Thus, various types of simulated casualty evacuations appear to be unique assess- ments requiring a multitude of abilities to garner success.

In addition, within the Army, several organizations have attempted to create a comprehensive fitness score; 101st Iron Eagle Challenge and the Ranger Raw Assessment. Both of these assessments appear to still have challenges related to BM bias as the Iron Eagle Challenge has four of the six events in which research has indicated are influenced by BM15,16 (pull-ups, dips, chin-ups, 3MR), and corrections need to be made before accurate classifications can be made.17 Further, the Ranger Raw Assessment has five events of eight that are influenced by BM (agility test, pull-ups, PU, heel claps, and 300-yard shuttle), in addition, one test favors larger BM indi- viduals16 (225-lbdeadlift;^102 kg), and one event offering potential regarding the mitigation of BM bias, a comprehen- sive Ranger Physical Assessement Test has multiple events favoring both light weight and heavy weight individuals.

The latest Army training and doctrine guidance related to PT, FM 7--2218 Army Physical Readiness Training indicates from a global PT perspective, Army units should emphasize endurance, strength, and mobility as critical cornerstone fac- tors in physical program design. Using current guidance and a belief that service members will still "train for the test," we set out to design a comprehensive Military Optimal Per- formance Challenge (MOPC) that would allow military members to conduct "military relevant" events, focus on assessing endurance, strength, and mobility and yet not be confounded by a BM influence relationship. Further, being sensitive to equipment issues and running in boots, we designed a MOPC-Light (MOPC-LT) that did not use the practice of running in boots or the use of specialized equip- ment other than those commonly found in any Department of Defense fitness center. The purpose of this research was three-fold: (1) create a comprehensive, criterion-measured MOPC and MOPC-LT devoid of the confounding influence of BM compared to the existing APFT, (2) investigate rela- Creation of a Criterion-Referenced MOPC ionships between "criterion-functional fitness percentiles", BM, APFT, MOPC, and MOPC-LT composite scores, (3) ini- tially, investigate through factor analysis about the relation- ships involved with APFT, MOPC, and MOPC-LT and each accompanying subcomponent factors (PU, SU, mobility for battle [MOB], etc.).

METHODS

Subjects were 20 male, military personnel (19 enlisted sol- diers, 1 military officer) of diverse body size and physical performance abilities (Table I). Subjects were volunteers, relatively fit, in active duty status, who were participating in a unit "ramp-up" PT program supported by their local battal- ion. All the subjects provided with written informed consent and the experimental design protocol and volunteer agree- ment affidavits were approved by a U.S. Service Academy's internal institutional review board and ethics committee.

The subjects were tested on the MOPC during a 10-day period under similar conditions. The subjects' APFT score was tested before the MOPC period under strict unit testing procedures. Officer and senior enlisted oversight on both test- ing sessions (APFT, MOPC) assisted with assessment condi- tions and standards. Related to the MOPC, the comprehensive assessment included 3MR, MOB Test, Upper and Lower Body Strength/Endurance, and a Simulated Casualty Evacuation Test (SCET). Appendix A shows test item controls related to the MOPC along with the subsequent specific testing parame- ters to insure standardization. All the assessments had a famil- iarization period before testing. Impact loading events (SCET, 3MR) were separated by at least 48 hours. All MOPC events with the exception of the SCET were conducted in military PT gear with running shoes and running belt. The 3MR was on a marked known circular, level, paved loop verified by a global positioning measuring tool. Subjects wore gym alpha, running shoes and covered the distance as fast as possible. Running lap splits were provided to assist with optimal performance. The MOB was performed on a tape measured course in accordance to the existing schematic representation (Fig. 1). Related to the MOB, the mobility assessment was created in 2006 to 2007, at a U.S. Service Academy in a year-long academic capstone, cadet-faculty project. Since the MOB's creation, it has been incorporated into a U.S. Service Academy's curriculum and administered to a large population of diverse (fitness, body composition, height) college-age and military-age subjects including both genders. Analysis of the performances has indi- cated this to be a comprehensive, reliable test assessing overall soldier mobility. In a well-supervised academic course, we found intra-class correlations for test, retest consistently revealed strong correlations (r0.91). Overall upper and lower body muscular strength endurance assessments were adminis- tered using existing protocols that have showed the ability to measure strength and remove the confounding influence of BM.19 Briefly, subjects had practice attempts in determining a testing performance weight. On separate testing days, subjects performed repetitions until volitional momentary muscular concentric failure for both upper body (bench press 185 lbs; 84 kg) and lower body (back squat 205 lbs; 93 kg). Both of these tests are positively influenced by BM.16,20 Upper body muscular fitness, 5-second cadence pull-ups (CPU) and upper body, "core" fitness, ankles to the bar (ATB) were assessed through standards found in Appendix A. Both of these tests are negatively influenced by BM.15,16 Using our existing assessment and scoring procedures,19 the aggregate score (bench press and 5-second CPUs; back squat, and ATB) mini- mized the impact of BM on the overall performance of the composite upper and lower body muscular fitness measures. The SCET was developed over several years (2007--2009) at a U.S. Service Academy that included the input and collabora- tive work of 10 company grade or higher officers. Speaking to deployed personnel and collaborative officers and assessing casualty evacuation demand, it was postulated casualty evacu- ation at times occurs after some period of fatiguing military work. In addition, Vanderburgh et al13 have reported a load- carriage distance run incurs no BM bias, an important point related to fair performance assessments. Therefore, the current SCET represented the previous mentioned input, thus subjects in the current investigation wore Army Combat Uniforms, Kevlar helmet, boots, and either military vest with ceramic plates or military vest alone. The subjects were weighed on a digital scale with gear and then performed a 1MR, followed by a 400-m run with dummy weapon and finished with a simu- lated casualty evacuation 140-m movement of a "casualty" (100 lbs; 45.5 kg sand-filled military ruck sack) while retaining the dummy weapon. No additional supporting gear (hydra- tion system, supplies, etc.) was worn. One platoon wore the armored vest and protective plates (14.5 kg) and one pla- toon wore armored vests (no plates) only (8.5 kg). Minor vari- ations of ensemble makeups due to size differences existed, however, subject inclusion weight differences were minor and nonsignificant ensemble differences existed when post-hoc fitness analysis were conducted. Exact standards are found in Appendix A. The casualty evacuation weight chosen of only 100 lbs represents the belief this is a "starting weight" to simulate casualty evacuation. Clearly, casualty evacuation may constitute the removal of any military individual with perhaps as high as 280+ lbs including or not including body armor from the battlefield. The intent of casualty evacuation regardless of weight, 70 to 100 lbs in our current and past research work, is to begin conducting assessments with this important warrior task and battle drill. Clearly, members of our relatively fit service academy population have challenges with 70 to 100 lbs simulated casualty evacuation and thus are intellectually internalizing the removal of an even heavier sub- ject (280+ lbs) would demand even more battle ready fitness work capacity.

In conjunction with all MOPC assessments, we conducted, height, weight, and percent body fat, which were attained using skinfold caliper measurements according to standardized Jackson and Pollock21 protocols and equations. Raw perfor- mance MOPC data measures were recorded and a composite score was attained using the criterion referenced scales con- tained in Appendix B. Two composite scores were created because of both a logistical and philosophical concern. The first score (MOPC) was tabulated using all 7 assessments. The second score (MOPC-LT) was tabulated with 6 assessments only and did not include the SCET, thus eliminating a logistical concern and possible medical concern (running in combat boots). We understand constant training, particular running in combat boots, may increase the incidence of lower leg injuries22; however, we believe our distances (<2,200 m) would minimize this exposure. Indeed, appropriate specificity training could be conducted in ACUs, military vests/plates and running shoes.

Statistical analysis involved the use of basic descriptive statistics, correlations, repeated measures ANOVA, and a factor analysis. (StatSoft, Tulsa, Oklahoma). For analyses, statistical significance was set at p£ 0.05. We also examined statistical significance at both p£ 0.01 and p£ 0.001. Initial analysis included correlations involving body composition (BM, LBM, and FM) and separate physical assessments (PU, SU, MOB, etc.) and composite scores; APFT, MOPC, and MOPC-LT. In addition, since the SCET was a unique multifaceted assessment involving 3 distinct subcomponents, specific analyses were conducted on this parameter and the attending subcomponent events. Repeated measures ANOVA involved creating a percentile for each composite score. This percentile measurement could be viewed as the fitness or physical readiness of each soldier with 100% indicating the highest "fit for duty" subject. Thus, APFT (%APFT score/300), %MOPC (MOPC score/250), and %MOPC-LT (MOPC/200) were created to assist in comparing field performances of the APFT, MOPC, and MOPC-LT. Factor analysis was used in an attempt to empirically elucidate the important factors required for battlefield readiness.

RESULTS

The means and standard deviations for the subject's anthro- pometric values and physical performance values are shown in Table I. The performance data indicated the subjects were "relatively fit," with a degree of diversity among the Army's readiness global construct variables (endurance, strength, mobility). Table II specifically showed the relationships of BM, LBM, and FM related to the MOPC, MOPC-LT, and APFT. Table II showed the negative impact of BM (-0.47) on APFT scores. In other words, the heavier a person, regard- less of fat mass or LBM, the lower the one's APFT score. Twenty-two percent of the APFT score variance was explained alone by one's BM. A (-0.45) correlation of LBM to APFT performance was found, although MOPC and MOPC-LT scores indicated enhanced LBM did not nega- tively impact MOPC and MOPC-LT performances. In the MOPC/MOPC-LT performance arena, higher BM (r = 0.13; r2 = 0.02) and a higher LBM amount (r = 0.24; r2 = 0.06) slightly, positively impacted overall MOPC and MOPC-LT performances. The MOPC or MOPC-LT variance accounted for BM, LBM, or fat mass was a mean value of < 3%, showing a "non" relationship for any MOPC or MOPC-LT composite performance score related to the anthropometric values. APFT had anthropometric factors that accounted for 19.7% of the score's performance variance.

Table III presented an intercorrelation matrix of the anthropometric, physical performance values (all subcom- ponent assessments), and the three composite scores (MOPC, MOPC-LT, and APFT). Of empirical relationship assistance would be to examine the composite scores (MOPC, MOPC- LT, and APFT) at the 0.01 level of significance as opposed to the 0.05 level of significance. Average mean correlation for PU (0.67) and 3MR (-0.59) were significant at the 0.01 level for each of the three composite scores. Two-mile run (-0.79) was significant with APFT composite score only. Additional field performance measures included the MOB, bench press, and back squat output. Finally, related to subcomponent measures, the SCET represented a multifaceted assessment, which has been developed with an aim to assess military type activities and also minimized the influence of BM on the performance of this assessment. Table IV showed the relationships related to anthropometric factors, SCET-specific components, com- posite SCET performance, and Vanderburgh's previous data examining load-carriage distance runs.13 Previous research and current research had the variance of BM and run performance in low magnitudes (0.004 and 0.01), respectively. Related to the composite SCET, as our subjects moved higher along the work intensity continuum (loaded mile, 400 m, 140 m 100 lbs casualty), we observed the greater contribution to LBM (r2 = 0.0004, 0.04, and 0.16).

Graphically, Figure 2 represented all 20 subjects (cases) and the %APFT and %MOPC found on the double y axes, respectively. All 11 subjects (Table V) achieved a MOPC score below 70% that indicated, perhaps, low military physical readiness. These 11 subjects as viewed by the APFT mean score achieved (84.2%); however, all the 11 subjects' mean score as %MOPC was <52% with %MOPC-LT even lower (43.3%). Conversely, also contained in Table V, the highest performing MOPC individual (232; 92.8%) had a relatively high APFT score (294; 98%). However, the lowest performing individual related to the MOPC (79; 31.6%) scored a high, moderate APFT score (236; 78.7%).

Further, of interest was examining the top performing soldiers related to the APFT score. The highest MOPC per- former mentioned above (232) was not included in this anal- ysis because of his rank (officer) and his high output on the MOPC. Therefore eight enlisted soldiers averaged 93.9% on the APFT (281.6) and scored 184.3 (73.7%) on the more robust MOPC. To further assist in interpretation of the cur- rent data, our analysis examined two distinct cut points related to the MOPC; MOPC <70%; (n = 11) and MOPC >70% (n = 9) and found significant performance factors for several variables. As shown in Table V, there was no real difference in BM and height, with the >70% group slightly leaner and having more LBM (6.8 lbs, p= 0.44). PU, 3MR, MOB, and 5-second CPUs were all significantly different between the two groups (p£ 0.05) although back squat output, ATBs, and SCET showed trends of significance ( p £ 0.10). Since these groups were formed based on MOPC score, both MOPC and MOPC-LT were significantly different between the two groups ( p < 0.0001), yet APFT scores were not significantly different between the two groups (266.3 vs. 252.3; p= 0.27). Taking the results found in Table V, and focusing on trends of significance below the p= 0.10 level, the group scoring MOPC >70%, have the following attributes using the Army's doctrine of military readiness (endurance, strength, mobility): 21 minutes or less 3MR, 11:40 or less for SCET, back squat 200 lbs for 13 repetitions, perform 10.5 repetitions for both cadence pull-ups and ATB, 68 repetitions for PU, and MOB of 88 seconds. Further, these subjects averaged 266 on the APFT.

Figure 3 examines the 2 groups (< or >70%MOPC) and supports the statement the %APFT score between the 2 groups was not significantly different (p= 0.27) yet the %MOPC was significantly different between the 2 groups ( p = 0.00005). Figure 4 graphically represents the results of all subjects, in a repeated tests approach with the addition of MOPC-LT to clarify interpretation and additionally shows both %MOPC and %MOPC-LT are not statistically different in compos- ite scores (p= 0.18), yet both are statistically different from %APFT (p= 0.0001).

Factor analysis (Fig. 5) revealed 6 "clusters" of like activity with regard to empirical analysis. PU and SU factored closely to APFT, with the addition of other specific BM centric activ- ities (ATBs, 5-second CPUs). MOPC and MOPC-LT collec- tively are in a different region than APFT suggesting they are measuring empirically, unique constructs compared to the composite APFT. Both the MOB and SCET were together in a cluster yet apart from both the cluster APFT and cluster MOPC, MOPC-LT areas again indicating unique constructs. The global constructs of endurance, strength, and mobility were distinctly represented leading to the creation of 6 unique clusters with a specific nomenclature description: Cluster 1 (Body Com- position): BM, LBM, fat mass, %body fat; Cluster 2 (Endur- ance): 3MR, 2MR; Cluster 3 (Strength): back squat and bench press; Cluster 4 (Mobility): MOB and SCET; Cluster 5 (Body Mass-Gravity Centric Activities): cadence pull-ups, ATB, SU, PU, and APFT; Cluster 6 (Aggregate Military Readiness): MOPC and MOPC-LT.

DISCUSSION

The results of this research provided a suggested template in an approach to assess the more robust factors for military readiness and yet minimize the confounding influence of BM. The rigors of combat are unquestioned, couple this with unknown terrain, altitude and climate, and personnel need to be highly fit for a myriad of demanding encounters. We are in agreement with the Army's traditional PT and doctrine model of the need to train and enhance endurance, strength, mobil- ity. If strength is such an important entity as viewed by the U.S. Army Training and Doctrine Command, why is there not an official strength test metric located within the official Army doctrine? Our current research offers two possibilities either a back squat or bench press to remedy this current limitation. Of important note, however, is to accurately address or account for BM while assessing the strength con- struct. The Bompa model of training23 characterized by the entities of strength, endurance, speed, and power serve as important reminders of physical attributes for high sustained performance. The Army's addition of mobility; the functional application of strength and endurance assist with focusing on the aspect indicating most military functional fitness involves some type of movement involving agility, change of direc- tion, along with some ballistic output. Our results of the MOB with regard to BM influence (r = -0.21; p= 0.37) is different than both Harman et al4 and Bishop et al24 related to obstacle course performance and BM. Harman found a (0.35) correlation, whereas Bishop found (0.59) related to BM and obstacle course performance. Our data is a negative relation- ship, thus the higher BM translates to lower MOB time, whereas their data relate to a slower time with increasing BM. We believe this could be explained as both of their obstacle courses involve some type of climbing (Harman's climb over 1.4-m high sheer wooden wall, climb onto a 1.55- m sheer-faced platform; Bishop-mounted a 2.2-m shelf, climbed a 2.2-m wall, surmounted a smooth 2.1-m wall). Our modified obstacle course (MOB) did not contain any climbing events. Thus LBM could be summated into speed and power as opposed to when climbing events are involved, either BM or LBM appears to be a decrement for climbing performance.16,17 Thus, both BM and LBM offer a hindrance in events where one must lift this mass upwards. Our data along with Harman's and Bishop's would support the current Army doctrine in which states both on-ground and off-ground activities should be performed during PT activities.

The concept of assessing an individual and mitigating the impact of BM, especially when promotion or pay grade raises may be involved, is paramount. Couple the previous fairness issue, with potential life and death demands on the battlefield, therefore indicating fair, functional military readiness assess- ments should be the goal. Our existing data is in agreement with Vanderburgh et al's13 work regarding the premise "loaded runs" minimize the influence of BM even though we had a lower amount of weight (21.5 vs. ^30 lbs) and shorter distance (1 mile vs. 2 mile). In Vanderburgh's study, by placing 30 lbs on an individual and having the subject perform both a maximal effort 2MR and a 2-minute PU test, BM influence is minimized. In this configuration, BM had an r of -0.06, 0.06 (p= 0.661) for 2MR and PU, respectively. Our composite assessment of either 7 (MOPC) or 6 events (MOPC-LT) had events that were both influenced positively and negatively by BM. However, the net scores were not impacted by BM r = 0.13 (p= 0.58).

We are in agreement with Harman et al4 when they state on the battlefield, there are activities other than casualty res- cue that also involve manipulation of relatively heavy loads (setting up field artillery, hauling heavy weapons/ammuni- tion). They further state these are activities at which larger soldiers, who may not excel at physical fitness tests, could also be at an advantage. We believe the "robustness" of our MOPC assessment whereby various specific events have both positive and negative relationships with BM is the strength of this research. Specifically stated, our efforts support other research,15,16 indicating BM impacts positively on the fol- lowing factors: 3MR (increase BM; increase run time), bench press, and back squat output, whereas negatively on MOB, 5-second CPUs, ATB, and SCET. Thus, when the criterion scores are summed, the impact of BM is minimized. Com- pared to the APFT in this study, BM significantly impacts APFT performance (p < 0.05) in a negative fashion (r = -0.47) as indicated in Table II and supported by existing data.1,2 Thus, perhaps the very individuals who may assist in the manipulation of heavy loads during battlefield activities are being penalized in the only "screening" assessment for both military readiness and promotional-salary evaluation.

Interestingly, both the PU and SU assessments provided the greatest number (4) of significant correlations with the other assessments. On one hand, this is a positive feature, in other words, if one test is significantly correlated with many other tests then the one test can stand as a single, surrogate measure for the others thereby reducing testing time and providing meaningful predictive value to military readiness. On the other hand, one should proceed cautiously, in paying particular attention to the assessments yielding the correlations. PU was significant with SU,MOB,CPU,ATB.SUwassignificantwithPU,2MR, MOB, ATB. Graphically this is easily observed in Figure 5. As indicated factor analysis yielded a cluster that would seem to be related to BM-gravity centric activities (PU, SU, CPU, ATB). Of note, the composite APFT score was in this cluster providing further evidence the APFT is significantly influenced by BM. If one takes the position of supporting the current Army doctrine of endurance, mobility, and strength, then one would expect to assess each of these respective entities. Further, because the global construct of endurance is unique and different from strength,onewouldnotexpecttheretobeasinglemeasure, which would assess both and certainly PU and/or SU does not. If one deems a specific global construct to be important to mili- tary readiness (endurance, strength, mobility), then one should assess these variables.

Multiconstruct aspects for military readiness are important concepts and supported by our research. As contained in Table V, the highest performing MOPC individual (232; 92.8%) had a relatively high APFT score (294; 98%) seem- ingly indicating a multicomponent, highly fit individual. How- ever, the lowest performing individual related to the MOPC (79; 31.6%) scored a high, moderate APFT score (236; 78.7%) perhaps, indicating some fundamental weakness in valuable military physical components, namely strength and mobility, which are not tested in the current APFT scenario. This would seem to be supported by the results in finding the individual could only bench press 155 lbs for one repetition, back squat 135 lbs for seven repetitions and ran the MOB in 110 seconds, 31 seconds slower than the fastest performing soldier. Further, of interest was examining the top performing soldiers related to the APFT score. The highest MOPC performer mentioned above (232) was not included in this analysis because of his rank (officer) and his high output on the MOPC. Therefore, eight enlisted soldiers averaged 93.9% on the APFT (281.6), yet only scored 184.3 (73.7%) on the more robust MOPC. These scenarios are troubling in both past1--3,5 and this present research indicated the current Army metric (APFT) for fitness is BM biased and further the APFT is not seemingly correctly classifying military readiness, at least as measured by the presently reported field friendly, robust MOPC.

Because we know from history, the APFT was formed to assess baseline fitness and not military readiness, it is still troubling when many individuals still hold the APFT in such high regard related to some form of "fitness." Because it assesses no muscular strength or mobility component it can hardly be a representative model for military readiness when one uses the current Army physical readiness doctrine (endur- ance, strength, mobility).18 In our study, examining the two distinct groups formed through MOPC/MOPC-LT scores (high, low; 70% cut points) we saw significant differences between the two groups ( p < 0.0001) yet APFT scores were not significantly different between the two groups (266.3 vs. 252.3; p= 0.27). This provides further evidence APFT scores may not be as sensitive to military readiness if one deems military readiness can be reflected based more on our military performance factors (MOB, 3MR, CPU, SCET, etc).

Injury prevention or "prehab" is an important concept in military readiness. Both running in our case (3 miles) and the SCET that demand a 1MR with ACUs, boots, vests, and protective armor plates are impact loading involving ground reaction forces. With repetitive running, ruck marching, or load-bearing running in our case, bone resorption in the lower extremities occurs before the bone remodels because of the training stimulus thus making the bone more susceptible to injury.22,25 Adoption of smart pro- gression guidelines related to impact loading and a preconditioning, abdominal strengthening, and/or lower extremity strengthening program can reduce the incidence of injury.22 Further, volume or time exposure to both ground reaction forces and vertical loading rates can be reduced by introduction to machine-based aerobic train- ing and high-quality periodic intensity interval training.

Related to age and gender, since this data involved only younger adult men (22--36 years), one cannot speculate the relationships of field-relevant assessments and military read- iness related to older-age men and women. Regardless to the age or gender, high physical military readiness is required in the profession of arms. Related to older age, a subject (age > 50) in this study was not included in data analysis, displayed high physical output (second overall after the offi- cer) compared to the enlisted population. The older-age sub- ject displayed the following: (300 [100%] vs. 256 [85.6%] APFT; 228 [91.2%] vs. 155.8 [62.3%] MOPC) compared to younger (22--36) aged enlisted soldiers. In this regard, further research is warranted related to both women and older indi- viduals. However, it is our belief regardless of the constructs that may yield predictive capabilities to military readiness, there should be a "one scale fits all" related to military read- iness. In other words, we believe that it is appropriate to have separate scales regarding gender and age with regard to, perhaps, promotion and financial remuneration. However, related to military/combat readiness, we believe in the one- scale ranking system. For example, on the 3MR, one would perform the event and then regardless of gender or age, all individuals would be ranked on one identified scale. Thus, specific performances could be judged based on the merit of performances only. In addition, we believe if one was then ranked accordingly as being military or combat ready, addi- tional financial amounts could be accrued. This is similar to current procedures related to combat or aviation pay.

One further concern related to the MOPC or MOPC-LT is the requirement of equipment. We believe in garrison, this will not be a concern. In combat, if existing strength equipment is not available, then our recommendation is that deployed sol- diers have a creatively constructed "Deployed-Light" MOPC or not test on the MOPC or MOPC-LT. There might be some objections to soldiers not testing while deployed, because this could mean some soldiers might not test within a calendar year. However, it is the primary responsibility for soldiers to stay fit year round, regardless of whether they test or not, and not requiring deployed soldiers to test may have administra- tive, psychological, and logistic benefits to operations.

In summary, these results suggest both the MOPC and MOPC-LT yield a composite military readiness score free of the confounding influences of BM by assessing critical entities the U.S. Army has deemed important to military readiness namely, endurance, mobility, and strength. Other organiza- tions have certainly been researching and reporting the impor- tance of task-specific tests related to military occupational performance5,10--13,26 and cautioning about the weak relation- ship of the APFT and military readiness.3 We believe the MOPC and MOPC-LT can contribute a small piece to assessing military readiness and assist commanders with infor- mation to empirically determine, "fit for combat." The MOPC is a unique assessment requiring a multitude of abilities to garner success and may assist in training for functional combat performance skills demanding high work capacities.

ACKNOWLEDGMENTS

Deep appreciation goes to our Hawaiian subjects, thank you for your tremen- dous maximal efforts and commitment to excellence in the profession of arms. Be safe. Personally, I thank my co-authors for providing insight, passion, real-world application, and warm hospitality on the North Shore, I appreciate both your efforts greatly. Appreciation also to soldiers, cadets, officers, and civil- ians who have provided inspiration and insight in many facets of our research. Finally, a sincere thanks to our reviewers who provided excellent comments and thus strengthened this research. Personal funding was used for the collec- tion of this data at Schofield Barracks, Oahu, Hawaii.

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Todd A. Crowder, PhD*; 1LT Andrew L. Ferrara, IN USA[dagger]; 1LT Max D. Levinbook, IN USA[dagger]

*Department of Physical Education, United States Military Academy, West Point, NY 10996.

[dagger]25th Infantry Division, Schofield Barracks, Oahu, HI 96857.

doi: 10.7205/MILMED-D-13-00081

(ProQuest: Appendix omitted.)