Functional Performance Testing Benefits in Rehabilitation

Can Functional Performance Tests Help Explain an Injury’s Real-World Impact?

Pain can tell a clinician something is wrong, but it doesn’t always show what an injury means in everyday life.

An athlete may say the knee feels better but still struggle to cut, jump, or land safely. A warehouse employee may report less back pain yet remain unable to repeatedly lift boxes from the floor. A construction worker may walk comfortably through the clinic but lose endurance after climbing stairs, carrying equipment, or maintaining a bent position.

This is where functional performance testing becomes valuable.

Instead of asking only, “How much does it hurt?” clinicians can also ask, “What can this person safely and consistently do?”

Functional testing may examine strength, balance, endurance, mobility, lifting tolerance, coordination, and task-specific performance. When interpreted alongside medical history, physical examination, imaging (when indicated), and the demands of the patient’s sport or occupation, these findings can provide a clearer picture of how an injury affects real-world function.

Research supports using functional capacity evaluations and performance tests in rehabilitation and return-to-activity decision-making, while recognizing that no single test provides a complete answer (Bieniek & Bethge, 2014; De Baets et al., 2018).

Moving Beyond the Pain Scale

Imagine two injured workers who both rate their lower back pain as a 4 out of 10.

The first can squat, carry 30 pounds, climb stairs, walk for 30 minutes, and repeatedly move between standing and kneeling without a meaningful problem.

The second develops increasing pain and altered movement after several lifts, cannot tolerate prolonged bending, and must repeatedly stop during tasks that resemble the physical requirements of the job.

Their pain ratings are identical.

Their functional abilities are not.

That distinction is one reason clinicians use performance-based measurements. Pain remains clinically important, but function provides another layer of information. The goal is not to challenge whether a patient is experiencing pain. The goal is to determine how that condition affects movement and activity.

At Dr. Jimenez’s PUSH as Rx program, the clinic examines athletes in motion and under supervised physical loads so they can observe strength, agility, mobility, mechanics, and performance limitations rather than assume them.

What Can Functional Performance Testing Measure?

The exact assessment should depend on the injury and the activity the patient is trying to resume. Testing an injured quarterback like a warehouse employee would provide limited useful information. Testing a warehouse employee only on a stationary exercise bike would have the same problem.

A functional evaluation may therefore include:

• Strength testing: Measures force production and may identify side-to-side differences, muscle weakness, or difficulty producing force in particular positions.
• Balance and postural control: Examines whether the patient can maintain control while standing, reaching, changing direction, or performing single-leg tasks.
• Muscular endurance: Looks beyond one successful repetition to determine whether a person can maintain performance across repeated activity.
• Lifting and carrying tolerance: Evaluates activities such as floor-to-waist lifting, carrying, pushing, pulling, or repeated material handling when those tasks are relevant.
• Mobility and movement quality: Examines range of motion and how the body coordinates movement during squatting, reaching, walking, bending, or other activities.
• Sport-specific performance: May include jumping, hopping, accelerating, decelerating, changing direction, throwing, or other movements required by an athlete’s position.
• Work-specific performance: Can reproduce relevant job demands such as stair climbing, kneeling, overhead work, lifting, carrying, sustained standing, or repeated bending.

The key word is relevant.

A test becomes more meaningful when it resembles the physical demand the clinician is trying to understand.

Testing Should Match the Claimed Limitation

Suppose a delivery driver says an injury makes repeatedly lifting 40-pound packages difficult.

A balance test alone cannot answer that question.

Likewise, if a soccer player says the ankle becomes unstable during rapid changes in direction, measuring grip strength tells the clinician almost nothing about that limitation.

The claimed problem should guide the assessment.

Current sports medicine research follows this same principle. Return-to-sport decisions may incorporate strength, endurance, power, balance, psychological readiness, functional performance, and sport-specific drills rather than relying on one measurement. For ankle injuries, for example, an international consensus identified pain, ankle impairment, athlete perception, sensorimotor control, and sport-specific functional performance as important domains to assess (Smith et al., 2021).

Recent research on return-to-sport testing also shows why clinicians need to choose assessments appropriate to the injured body region, sport, and performance demands rather than assuming a single universal test battery (Lavoie-Gagne et al., 2024).

Why Strength Testing Can Be Especially Useful

Strength is one of the easier functional characteristics to quantify.

A clinician may compare the injured and uninjured sides, evaluate force in specific movement patterns, or determine whether the patient can safely perform progressively demanding activities.

For workers, strength testing may be paired with lifting and carrying tasks. For athletes, testing may be combined with jumping, hopping, throwing, sprinting, or other sport-specific movements.

A systematic review of the WorkWell functional capacity evaluation found consistently acceptable reliability for weight-handling and strength testing, although other testing categories showed more variable results (Bieniek & Bethge, 2014).

That does not mean strength testing is perfect. It means standardized strength and material-handling measures can provide useful objective information when administered correctly and interpreted in context.

Unlocking Pain Relief: How We Assess Motion to Alleviate Pain | El Paso, TX

Endurance Can Reveal What a Single Repetition Misses

A patient may successfully lift an object once.

What happens after the tenth repetition?

An athlete may complete one sprint without difficulty.

Can the athlete repeat the effort without deteriorating mechanics?

An employee may tolerate five minutes of standing.

Can that person continue for the length of time required by the actual job?

Endurance testing examines what happens as the demands continue. This can reveal limitations that may not appear during a brief office examination.

Fatigue may change movement mechanics, balance, coordination, speed, or pain. For athletes and active workers, these changes matter because sports and physically demanding jobs rarely involve a single isolated movement.

Balance and Movement Control Matter Too

Strength is only part of physical performance.

A person can have strong muscles and still demonstrate poor balance, altered coordination, limited mobility, or inadequate control during dynamic movements.

Dr. Jimenez’s clinical examination materials describe evaluating range of motion, muscle strength and tone, walking gait, posture, neurological integrity, and other orthopedic or neurological findings when appropriate.

For an injured athlete, functional progression may add increasingly demanding movement tests to that clinical examination. Low-intensity activities can progress toward faster, multiplanar, higher-impact, and eventually sport-specific movements as clinically appropriate.

Experts studying functional testing for hip conditions have similarly recommended using objective scoring criteria and grading performance tests according to the patient’s individual characteristics and activity demands (Freke et al., 2023).

What About Patient Effort?

Effort is an important—and sometimes misunderstood—part of functional testing.

A performance result depends partly on how much the individual can or is willing to perform that day. Pain, fear of reinjury, fatigue, misunderstanding the instructions, unfamiliarity with the movement, anxiety, conditioning, motivation, and actual physical impairment can all influence performance.

That means a low score should not automatically be interpreted as poor effort or exaggeration.

Research has found that clinicians can achieve reasonable agreement when evaluating effort during some functional capacity tests, but reliability varies depending on the task and method being used. Material-handling tasks tend to produce more consistent observations than some postural or ambulatory activities (Trippolini et al., 2014).

Responsible interpretation therefore requires more than watching someone complete one task.

The examiner should consider consistency across multiple measurements, observed mechanics, symptom behavior, repeated performance, neurological and orthopedic findings, and whether different findings make clinical sense together.

Reliability Requires Standardization

For a functional test to be useful, another properly trained examiner should ideally be able to perform the same assessment under similar conditions and obtain a reasonably comparable result.

That requires consistency.

Clinicians should document factors such as the test performed, equipment used, load, number of repetitions, distance, time, instructions, rest periods, stopping criteria, pain or symptoms, and the reason a test was discontinued.

Testing conditions also matter.

A patient completing a test after a full rehabilitation session may perform differently from someone tested while rested. Likewise, changing the equipment or technique between evaluations makes comparisons harder.

Research on functional capacity evaluations shows that reliability varies across systems and individual test components. For this reason, interpret results as part of a larger clinical assessment rather than an infallible score (De Baets et al., 2018).

Functional Testing and the Real-World Impact of an Injury

Functional testing can be especially valuable after a workplace accident, motor vehicle collision, sports injury, or other traumatic event because an injury’s consequences may extend beyond the examination table.

An injured person may have difficulty:

working a full shift,

lifting children,

carrying groceries,

climbing stairs,

training at the previous intensity,

running,

sleeping comfortably,

performing household tasks,

or participating in recreational activities.

Documenting these limitations can help link clinical findings to the patient’s day-to-day experience.

However, functional performance testing should not be confused with a test of causation.

A lifting test cannot, by itself, determine whether a specific accident caused a particular spinal injury. A balance test cannot establish when neurological dysfunction began.

Instead, functional measurements help document what the patient can and cannot do at the time of testing.

Causation requires a broader analysis of the mechanism of injury, timing of symptoms, examination findings, prior medical history, diagnostic evidence, alternative explanations, and clinical course. Dr. Jimenez’s causation materials similarly emphasize that no isolated functional or orthopedic measurement establishes accident causation and that measurement variability, patient effort, examiner technique, and diagnostic specificity must be considered.

Comparing Performance With the Actual Job

Functional capacity evaluation becomes particularly useful in return-to-work rehabilitation when performance can be compared with documented job demands.

For example, suppose a worker’s job requires regularly lifting 50 pounds from floor to waist.

If testing shows safe performance only at substantially lower loads, the clinician has measurable information to inform return-to-work planning.

The same concept applies to carrying, pushing, pulling, stair climbing, prolonged standing, kneeling, repetitive squatting, or other occupational demands.

Research indicates that valid functional capacity evaluations can provide objective information supporting medical assessments of work-related strength and fitness for duty, although return-to-work decisions still require clinical judgment and consideration of the job itself (Pransky & Dempsey, 2019).

Customized evaluations may be particularly valuable because they compare the patient’s capacity with the demands that actually matter. One study found that patients whose evaluated functional capacity matched their job demands were significantly more likely to return successfully to work (Bethge et al., 2020).

What Makes Injury Medical Clinic Different in El Paso?

Injury Medical Chiropractic and Functional Medicine Clinic uses a multidisciplinary model that combines medical oversight, chiropractic assessment, nurse-practitioner-level evaluation, rehabilitation, functional training, and performance-focused care. Dr. Maria Guadalupe Cardenas, MD, a board-certified internal medicine physician with more than four decades of clinical experience, serves as medical director and collaborative physician. Dr. Alex Jimenez, DC, APRN, FNP-BC, combines his chiropractic background with his role as a board-certified family nurse practitioner and specializes in evaluating and rehabilitating musculoskeletal, spinal, and soft-tissue injuries. According to the clinic’s published materials, Injury Medical Clinic PA is the only El Paso clinic that combines this medical-director model with dual licensure and a soft-tissue injury focus.

That integration can be especially useful when an athlete or injured worker needs more than pain treatment alone. A coordinated plan can consider structural findings, neurological function, medical considerations, movement mechanics, strength, mobility, and progressive rehabilitation rather than viewing them as unrelated problems.

From “I Feel Better” to “I Can Do More”

Recovery is not simply the disappearance of pain.

For an athlete, recovery may mean cutting confidently, generating power, maintaining balance under fatigue, and completing practice without symptoms.

For an active worker, it may mean safely lifting, carrying, climbing, bending, kneeling, or completing an entire shift.

For another patient, the goal may simply be walking farther, sleeping better, exercising again, or returning to normal family activities.

Functional performance testing helps make those goals measurable.

When the right test is used for the right patient—and interpreted alongside the complete clinical picture—it can turn a vague description of limitation into clear evidence of physical ability, progress, and remaining rehabilitation needs.

The most important question, therefore, is not simply, “Does it hurt?”

It is also:

“What can you safely do now, and what do you need to regain before returning to the activities that matter most?”

---

References

Bieniek, S., & Bethge, M. (2014). The reliability of WorkWell Systems Functional Capacity Evaluation: A systematic review. BMC Musculoskeletal Disorders, 15, 106.

De Baets, S., Calders, P., Schalley, N., Vermeulen, K., Vertriest, S., Van Peteghem, L., Coussens, M., & Malfait, F. (2018). Updating the evidence on functional capacity evaluation methods: A systematic review. Journal of Occupational Rehabilitation, 28, 418–428.

Pransky, G., & Dempsey, P. G. (2019). Evaluating return-to-work ability using functional capacity evaluation. Physical Medicine and Rehabilitation Clinics of North America, 30(3), 541–555.

Smith, M. D., Vicenzino, B., Bahr, R., Bandholm, T., Cooke, R., Mendonça, L. D. M., Fourchet, F., Glasgow, P., Gribble, P. A., Herrington, L., et al. (2021). Return to sport decisions after an acute lateral ankle sprain injury: Introducing the PAASS framework. British Journal of Sports Medicine.

Trippolini, M. A., Dijkstra, P. U., Geertzen, J. H. B., & Reneman, M. F. (2014). Reliability of clinician-rated physical effort determination during functional capacity evaluation in patients with chronic musculoskeletal pain. Journal of Occupational Rehabilitation.