PERFORMANCE OPTIMIZATION AND INJURY PREVENTION STRATEGIES FOR THE ARMY PHYSICAL FITNESS TEST: TECHNIQUE MATTERS

Abstract

The Army Physical Fitness Test (APFT) is a biannual training requirement for all soldiers. The Army has made significant overall fitness gains by developing functional and comprehensive Physical Readiness Training (PRT) programs, but more emphasis on individualized physical fitness test taking technique is warranted in order to optimize performance. The purpose of this clinical commentary is to provide clinicians with several examples of APFT performance enhancement techniques that can potentially be applied not only in the Army, but throughout the military and in the sports community where general fitness assessments are routinely administered.

Level of Evidence

5

BACKGROUND

The concept of human performance optimization has garnered a lot of attention within the military in recent years.¹ While there are multiple facets (physical, nutrition, cognitive, psychological, etc.) that have to be addressed for an individual to attain the highest level of performance, physical training and functional fitness is definitely a key component. Periodic generalized physical fitness assessments are a commonly utilized tool in the military, in addition to numerous sports organizations.^2,3 The Army Physical Fitness Test (APFT) is aimed at measuring cardiorespiratory endurance, upper and lower body muscular endurance and currently serves as a unit commander's generalized fitness assessment of his/her soldiers.⁴ The events making up the APFT include: two minutes of push‐ups, two minutes of sit‐ups, and a two‐mile run. Each event is worth a maximum of 100 points and is based on an age and gender based scoring system. A minimum score of 60 points in each event is required to receive a passing grade. The test itself has remained relatively unchanged for well over 30 years.⁵ During that time a common performance improvement strategy has revolved around increasing the training volume and intensity of the events where improvement was desired, with the “prevailing thought” being, if you do enough push‐ups, sit‐ups, and running, scores will eventually improve. More recently, the Physical Readiness Training (PRT) program was implemented in order to provide a more balanced training stimulus, prevent musculoskeletal injuries, and improve physical fitness.^6-8 Improving muscular endurance and aerobic capacity is undoubtedly the most important aspect of improving APFT scores. Moreover, several studies have provided research support for cross training and the greater variety of exercises found in the revised PRT program.^9-11 In some cases, a high level of baseline physical conditioning is enough to help individuals to achieve acceptable and occasionally even maximum scores. Other components that are essential for maximizing performance on the APFT have been recently stressed as a part of the Army Performance Triad initiative including proper sleep and performance nutrition.¹²

However, just like the technique aspect of any sports performance, technique likely matters for optimizing APFT scores as well. It might seem reasonable to assume that soldiers will self‐select an exercise strategy for each of the APFT events, be it for practicing or testing, that will likely yield optimal results if training occurs on a consistent basis. This is not always the case, some choose an exercise strategy based on ease of movement or comfort, regardless of how biomechanically or physiologically efficient it may be. To the authors’ knowledge, no published research or even expert guidance has addressed specific techniques aimed at improving APFT performance. The purpose of this commentary is to highlight some of the common deficiencies that can be observed in soldiers performing the APFT and provide technique recommendations to optimize performance. Since minimal research or data is available to frame this discussion, some of these recommendations are based off of commonly recognized biomechanical and physiologic principles along with the clinical experience of the authors. Given the advanced knowledge of biomechanics, functional movement analysis, and exercise physiology that sports physical therapists possess, they are ideally suited to provide this kind of service.

APFT EVALUATION

Principles of Performance

Perhaps the most relevant biomechanical principle to APFT technique concerns the concept of “torque”, which is simply the force (or weight) applied multiplied by the length of the lever arm (i.e. torque = force x lever arm).¹³ A simple example can be illustrated by holding a gallon of milk. If held close to the body, a gallon of milk doesn't feel excessively heavy because it's exerting a fairly small “torque” on the shoulder due to a small lever arm. However, if held with an outstretched arm, the same gallon of milk feels quite heavy (larger torque) due to the increased lever arm. Similarly, from an exercise physiology perspective, the amount of “work” that a muscle performs is determined by the forces exerted (weight) multiplied by the distance moved (i.e. work = force x distance).¹³ Therefore, it will take much more work for the shoulder muscles to lift a gallon of milk 10 times with the arm outstretched than it will to lift it 10 times close to the body. Additionally, the amount of “work” that a muscle expends during repetitive lifts is the sum of the work that occurs during the lifting phase (concentric contraction) and that which occurs during the lowering phase (eccentric contraction). Although eccentric contraction may protect the muscle, joints, tendons, and ligaments from stress of ballistic deceleration, it requires substantial muscle work without contributing to higher number of repetitions. The ability to produce and sustain mechanical work done by the musculoskeletal system is facilitated through the conversion of metabolic energy. Physical fitness and nutrition status play a key role in developing an efficient system of energy utilization to fuel physical performance. Further, choosing movement strategies that minimize unnecessary energy expenditure will likely lower the metabolic cost associated with that activity.

Two Minute Push‐up Event

Soldiers are required to descend while maintaining the trunk and lower extremities in a generally straight line until the upper arms are parallel to the ground in order for a repetition to be counted. They are allotted two minutes for this event, which is a significant amount of time to continuously perform push‐ups. It has been anecdotally observed that some soldiers do not utilize the full two minutes because they reach fatigue and/or they choose to conserve energy for a subsequent event. Those who do utilize the full time allotment typically expend an excessive amount of energy particularly within the last 30 seconds or so to only produce a handful of repetitions that may not all end up counting. A common reason for repetitions to not be counted is failure to descend low enough. Soldiers should attempt to achieve their maximal score within the first 90 seconds. The primary ingredient to achieve this is proper pacing. Repetitions during the test need to be done quickly, but not so quickly that a grader cannot determine if the performance standards were met, potentially resulting in a repetition not counting. Soldiers should strive to never have a repetition be uncounted as it becomes a waste of energy that could have downstream effects on the current or a later event. Given a 10‐minute rest period is prescribed between each event, this time period may result in suboptimal recovery.¹⁴ This can adversely affect performance on the sit‐up event which is also a local muscle endurance event that maximally challenges anaerobic endurance of the core musculature. Those who struggle with this event, often expend too much energy by lowering themselves too slow during the down phase, which requires increased eccentric muscle action.¹⁵ This can lead to premature fatigue and is a less than optimal test performance strategy. The down phase should be led by the chest, not the head or the abdomen and should require little to no muscular work. Often, soldiers will allow the head to flex and lead the down phase which gives the false appearance of going farther down than the body actually travels, possibly resulting in one or more uncounted repetitions.

Generally, the up phase is easier to sustain¹⁶ and is more quickly achieved than the down position.¹⁵ The up phase can be made more difficult by the selection of hand position. The hands should be just slightly more than shoulder width apart. Positioning the hands too narrowly will cause excessive work of the triceps and pectoralis major muscles¹⁷ leading to premature fatigue. Positioning the hands too wide, depending on arm length, can increase the lever arm possibly requiring more work of the pectoral muscles and increase anterior strain at the glenohumeral joint. Seek to find a hand position that will allow the upper arms to be positioned less than 60 degrees abducted away from the body when viewed from the top and the forearms oriented vertically. (Figures 1 and 2) This positioning is preferred to avoid scapular positioning that could lead to shoulder impingement.¹⁸ In the presence of hypothenar wrist pain a wider hand position may be better tolerated, and conversely, a narrower hand position may be more comfortable if a soldier has some thenar wrist pain.¹⁹

Figure 1.

Recommended arm position during the push‐up event.

Figure 2.

Vertical orientation of forearms during push‐up event.

The position of the foot and ankle can also serve to make this event more challenging. For example, those who perform push‐ups in any degree of ankle plantar flexion are expending more energy than necessary. (Figure 3) This ankle motion results in a longer lever arm of the body causing more weight to be borne through the upper extremities.²⁰ The individual should seek to maintain the ankle in some degree of dorsiflexion throughout the event if the range of motion is available and comfortable. (Figure 4) Per regulation,⁴ the foot contact points can be placed together or up to 12 inches apart. Some soldiers keep their feet separated during the push‐up event, which challenges the lower extremities to achieve a stationary position with only minimal surface area contact that is provided by the distal aspect of the shoes. To increase the active and passive stability of the lower extremities and trunk, place the feet about 3‐4 inches apart and then allow the heels come into contact with one another. When viewed from the rear it will form a triangle shape (Figure 5). The authors refer to this position as the “stability triangle”, because it allows the lower extremities to brace against one another serving as an anatomic splint. Further, when the heels and medial thighs push into one another with mild to moderate force it creates muscle activity in the powerful gluteal musculature, the pelvic floor, lumbar paraspinals, and even the periscapular musculature which should assist in maintaining the trunk in a proper plank position.²¹

Figure 3.

Ankle plantarflexion results in more weight being borne through the upper extremities.

Figure 4.

Ankle dorsiflexion helps to better distribute weight‐bearing between the upper and lower extremities.

Figure 5.

The stability triangle position.

Breathing is another aspect that is often overlooked and can result in diminished performance. Remembering to breathe consistently and purposefully to ensure adequate oxygenation for the working muscles is important. Trying to exhale during the up phase is generally recommended in order to avoid a Valsalva maneuver.²²

Soldiers are authorized to rest at one or more points during the event. Short rests will potentially help achieve more repetitions as long as the primarily fatiguing muscles (pectorals and triceps) are allowed to mostly relax. There are only two authorized rest positions: flexing or arching the back while maintaining the original position of the four points of contact. Resting in the flexed position while sticking the buttocks as high in the air as possible (i.e. “tenting”) is the position that allows the sternocostal portion of pectoralis major and rectus abdominis muscles to be the more relaxed²³ and presumably would result in the lower extremities bearing more weight. Additionally, by resting in this flexed position, it will be easier to lower the trunk back to the starting position, as opposed to actively raising your trunk back up from an arched low back position to the starting position. On a final note, any soldier that struggles to adequately recover following the push‐up event should seek to be in the front of the respective testing line in order to maximize rest periods.

Two Minute Sit‐Up Event

With the feet held in place, soldiers are required to perform as many sit‐ups as possible while maintaining the knees at a 90‐degree angle and ensuring the shoulder blades touch the ground at the end of each repetition. A key checkpoint is to ensure that the vertical position is achieved, that is when the base of the neck is above the base of the spine. (Figure 6) Additionally, soldiers are not permitted to lift their buttocks off the ground at any point during the event. Unlike the push‐up event, when done correctly and consistently, the sit‐up event can be usually done with proper form for the entire allotted time. Again pacing is very important in this event, as a quick yet sustainable pace is preferred. Many try to go too fast and burn‐out within a minute and struggle significantly in the second half of the event resulting in fewer counted repetitions and marked energy expenditure. Soldiers should seek to do an equal amount of repetitions during each minute of the event. Consistent and purposeful breathing and avoidance of Valsalva maneuver is again of paramount importance during this test.²⁴ The first step is to ensure that the entire testing area, particularly when outdoors, is inspected to ensure that there is not a disadvantageous slope present, but also to make sure there is no portion of the terrain that will interfere during the test (i.e. sticks, rocks, ants, etc.). Ensure that the soldier tasked with holding the feet has a firm and comfortable hold whether a heel contact or foot flat contact is preferred. Understand that a heel contact will require more muscular work from the front part of the lower leg, and a foot flat position requires more muscular work from the thighs.²⁵ Both can have consequences during the two mile run event, so some experimentation may be needed to determine which does not adversely affect leg drive and muscular endurance during the run. That said, a foot flat position is easier for a holder to stabilize and should result in less inefficient lower extremity rotational motion during the up phase of the sit‐up. Regardless of the foot hold technique, it is recommended to keep the feet approximately four to six inches apart during the test. Soldiers should visualize that they are lying on a pair of railroad tracks with the goal being to appropriately align the shoulder with the thigh and the foot for both the right and left side. (Figure 7) The rationale for this stems from the notion that hip flexor musculature is very active during the sit‐up event.²⁶ Maintenance of uniplanar motion could prevent unnecessary energy expenditure particularly on the up phase when some Soldiers allow their thigh(s) to move inward toward one another or outward away from one another. Ensure that the fingers remain tightly interlaced as low on the neck as possible. Keeping the hands low should minimize the torque (weight) of the trunk being lifted, thereby potentially increasing the number of repetitions possible. Placing the hands too high can potentially cause soldiers to pull on their head and strain their neck. Also, a common reason for stopping the test is due to the fingers slipping off the neck. Next, ensure that the knee angle is maintained at 90 degrees throughout the event. If the buttocks are allowed to slide closer to or further away from the heels that will result in sit‐ups that may not count and/or be more unnecessarily difficult to perform due a mechanical disadvantage.

Figure 6.

The vertical position of the sit‐up event.

Figure 7.

Recommended thigh alignment during the sit‐up event.

Ensure that the necessary amplitude of movement for both the up and down phase of the sit‐up is not exceeded. Some soldiers choose to move so far up such that their chest nearly touches the thighs. This exceeds the standard vertical position and is not necessary; further it results in more energy and time being required to complete each repetition. Another potential pitfall, especially from soldiers taking their first APFT, is choosing how to expend the least amount of energy on eccentric contraction during the lowering phase. Some choose to completely relax their abdominal muscles during the down phase, which requires a rapid concentric contraction in the down position and sometimes a lifting of the buttocks off the ground in order to reverse direction back into the up position. An alternative to this would be to somewhat, but not completely, relax the abdomen to allow a quick down phase that can be stopped at the point of shoulder blade‐ground contact followed with a rapid reversal of direction. This again will require some training to become comfortable with, but the use of a rolled hand towel placed perpendicular to and at the level of the middle of the scapulae to provide an inexpensive form of biofeedback is recommended. Soldiers should avoid allowing the elbows to move rapidly outward during the transition from the down phase to the up phase. This is commonly referred to as winging and results in unnecessary energy expenditure, a static position where the elbows are angled slightly to the outside of the thighs is recommended.

The last point to make is for the individual holding the tested soldier's feet. Most soldiers sustain a position that has a majority of their bodyweight being borne through the upper extremities for the duration of the event. This is not needed, so consider shifting the weight forward toward the upper extremities when the tested Soldier goes down and then shift toward the feet as the tested Soldier comes up. (Figures 8 and 9) By staying in rhythm with the tested Soldier in this manner the end result is less energy expended by the holder.

Figure 8.

Recommended foot holding technique during the down phase of the sit‐up event.

Figure 9.

Recommended foot holding technique during the up phase of the sit‐up event.

Two Mile Run Event

This is the culminating event of the APFT and requires a reasonable amount of cardiopulmonary and muscular endurance to meet or exceed the standard. In many cases, a planned and periodized increase in training volume is a large part of the solution for this event. However, self‐selected running styles are not always the most efficient or comfortable method available to the soldier. A brief but thorough evaluation of running form can easily be done utilizing a commercial treadmill and a smartphone with a native camera. It is ideal, but not essential, to have the ability to view the runner using slow‐motion video as well (preferably at a minimum rate of 120 frames per second). First, while there is no one ideal way to run there are some basic principles that most will agree upon. When running the head should be upright and the shoulders back to allow for more efficient breathing. Elbows should be bent at about 90 degrees and the fingers gently curled. There should be a very minimal amount of forward trunk lean on level surfaces. It is recommended to first look at the soldier running real time without videotaping in order to get a general sense of the running gait. Different aspects of running form can be revealed by looking from different angles, so at a minimum a lateral and posterior view should be obtained. From the lateral aspect, one can easily discern the relative stride length, foot strike pattern, and vertical displacement. Stride length will vary by individual, however, assess for those who over stride. This occurs when the foot strikes the ground forward of a line drawn straight from the trunk to the ground. (Figure 10) The result of this is a less efficient running gait and an increase in ground reaction forces being absorbed by the lower extremities.^27,28 While it may take some practice and probably the use of a metronome, shortening the stride length slightly and increasing the cadence slightly may help to overcome this issue and decrease loading in the lower extremities.^29,30

Figure 10.

An example of excess vertical displacement and over striding.

There is a significant amount of research regarding the relative value of the various foot strike patterns.^31-34 A majority of runners today utilize a heel strike pattern in which the heel of their running shoe strikes the ground first. There is some evidence to suggest that this results in increased ground reaction forces being absorbed within the lower extremities and could increase risk for injury.³⁵ Other less common foot strike patterns are mid‐foot strike and forefoot strike. These landing strategies can result in decreased joint reaction forces but also result in increased muscle activation within the plantarflexors, particularly during early stance phase.³² It is unclear at this point, if there is a preferred foot strike pattern that should be considered to either increase running performance or decrease risk for running related overuse injury. It has been reported that individuals are not that reliable at self‐reporting the type of foot strike pattern they utilize, nor does the type of shoe worn dictate the type of foot strike pattern that is utilized.^36,37

Lastly, the amount of vertical displacement of the body during running (i.e. “bounce”) needs to only be about 2‐3 inches. It is very common to see soldiers displace vertically well in excess of that distance, often referred to as pistoning. Pistoning results in more energy being expended in the vertical rather than the horizontal direction, in addition to greater joint stress being absorbed during foot strike.³⁸ Soldiers should be encouraged to accelerate more using their calf muscles and less with their thighs and hips.³⁹ A simple rule of thumb is to try to be more of a “glider” than a “bouncer”. From a visual standpoint, trying to keep some fixed point in a narrow visual field is another method to address this. Also, asking an individual to try to land more quietly with each step can also be helpful.

From the posterior vantage point a couple of key checkpoints include assessing for excessive pelvic or trunk rotation and assessing the stability of the pelvis. Only a minimal amount of contralateral trunk and pelvic rotation is required during running gait. Arm swing is a common by‐product of this out of phase rotation. Again, it is generally minimal and serves to decrease metabolic cost and improve lateral balance.⁴⁰ However, in an effort to generate more speed some soldiers may attempt to vigorously swing the arms, which is typically evident when the hands are observed to pass above the level of the shoulders. This amount of arm swing could be considered excessive and likely result in unnecessary energy expenditure. The feet typically approach, but do not cross the midline. The faster the run the closer to midline the foot strike will become. For most jogging speeds, there is generally a small separation between the landing points of each foot. The pelvis should not be expected to noticeably drop on the side opposite the stance leg. (Figure 11) This can possibly result in decreased performance and increased risk for injury.⁴¹ If present, initial intervention should include a hip endurance and strengthening program, especially of the lateral hip musculature.

Figure 11.

Initial contact on the right side should not result in a significant drop of the opposite pelvis.

From a strategic standpoint, there are a number of things to consider before and during the run event. Generally speaking, a dynamic warm‐up lasting no more than 2‐4 minutes prior to the run in order to prepare is reasonable. For improved biomechanical properties offered by running shoes they should be laced snugly but not too tight, ensuring that there is no possibility of them becoming untied during the run.⁴² At the start, it is not recommended to sprint out of the starting line, rather take about 5‐8 seconds to get up to a comfortable initial jogging speed. This jogging speed should be pre‐determined based on prior training that will let an individual know how fast to run each quarter mile of the two miles in order to achieve an optimal finish time. Using a planned pace will help to prevent any surprises during the test which could lead to increased anxiety and fatigue resulting in decreased performance. Proper pacing will prevent premature fatigue that is commonly seen during the APFT run event. If performed correctly, the second mile time should be faster than the first. Breathing control is again important; making every effort to breathe diaphragmatically and use the accessory muscles of the chest and neck minimally. A rhythmical breathing pattern where inhalation occurs over two to three steps and exhalation then occurs over the next two to three steps is a common practice.^43,44 Deeper breathing or pursed lip breathing for a few breathing cycles may help to restore a comfortable and consistent breathing pattern as needed during the run.^43,45 Breathing through the nose as much as possible, particularly during cold weather, helps avoid possible airway irritation.

DISCUSSION

This clinical commentary was specifically intended to address individual performance during the APFT. However, the other military services and various sports organizations that utilize similar generalized physical fitness assessments could also potentially benefit from the implementation of a program that exploits the functional movement analysis skill set of the physical therapists that support those client populations. Further, excelling on the APFT is a common long‐term rehabilitation goal for many injured soldiers. Therefore, the information contained in this commentary can assist sports physical therapists conducting advanced rehabilitation in addition to optimizing human performance. In addition to the PRT program, it should be noted that there are several comprehensive functional physical fitness programs that have shown promise regarding the ability to improve physical fitness measures to include the APFT.^46-48 The authors believe if the technique‐specific training presented in this commentary is incorporated into the aforementioned programs, there is the possibility of a synergistic effect. When available, attempts to draw upon available research evidence have been made with regard to making the aforementioned recommendations. However, field trials are now warranted to validate the effectiveness of these suggested performance techniques.

An evaluation of APFT technique can easily be completed during one 30‐minute clinical session. At that time, the appropriate technique modification(s) can then be incorporated into an existing regimen assuming that there is an appropriate level of training volume and intensity.⁴⁹ Whereas, some training modifications may require additional time and training in order to be incorporated correctly, others may be readily correctable and could theoretically lead to immediate improved performance. The goal of any periodized training program is to deliver peak performance at the right time in the training cycle, and this should be taken under consideration when making any technique modifications.

Lastly, it has been well documented that physical training results in a large number of musculoskeletal injuries.⁵⁰ The level of physical effort provided during the APFT typically reaches maximal exertion not encountered during typical physical readiness training sessions. As a result, more serious injuries and illnesses have been reported during the conduct of the APFT.²⁴,^51-53 This provides even more incentive to ensure that soldiers are using the most biomechanically and physiologically sound techniques to complete the APFT.