161
Maximal Effort During Functional Capacity Evaluations:
An Examination of Psychological Factors
Glenn M. Kaplan, PhD, Sandy K. Wurtele, PhD, Debra Gillis, RPT
ABSTRACT.
Kaplan GM, Wurtcle SK, Gillis D. Maximal
effort during functional capacity evaluations: an examination
of psychological
factors. Arch Phys Med Rehabil 1996;77:
161-4.
Background and Purpose: Patients with low back pain are
often administered a Functional Capacity Evaluation (FCE) to
determine levels of physical functioning at the conclusion of
their rehabilitation
program. The purpose of this study was to
examine the relationship between psychological factors (ie, selfreported disability, anxiety, depression, self-efficacy) and maximal effort exerted during the FCE.
Subjects and Methods: Sixty-four patients with low back
pain were administered
the Oswestry Low Back Disability
Questionnaire, Beck Depression Inventory, State-Trait Anxiety
Inventory, and the FCE Self-Efficacy Scales before administration of the FCE.
Results: Compared with patients who gave maximal effort
during the FCE, patients who did not exert maximal effort reported significantly
more anxiety and self-reported disability,
and reported lower expectations for both their FCE performance
and for returning to work. There was also a trend for these
patients to report more depressive symptomatology.
Conclusion and Discussion: Results provide evidence for
the relationship
between self-reported
disability, depression,
anxiety, self-efficacy, and patients’ performance on the FCE.
Suggestions for addressing the psychological factors in a comprehensive pain treatment program are provided.
0 1996 by the American Congress of Rehabilitation
Medicine
and the American Academy of Physical Medicine and Rehabilitation
P
ATIENTS with low back pain often go through a course of
physical therapy as part of their rehabilitation
program. At
the conclusion of physical therapy, a Functional Capacity Evaluation (FCE) is often administered. The FCE is a comprehensive,
objective test of a person’s ability to perform work-related
tasks.‘.’ FCE results are used by physicians and physical therapists to determine patients’ current physical capabilities and to
establish guidelines for physical restrictions and suitability for
return to work. Thus, the FCE is important in determining if,
and/or when, patients may return to their previous levels of
employment. To obtain a valid assessment of patients’ abilities
to perform work-related tasks, it is essential that they give acceptable maximal effort during the tests.’ Although FCE pcrformance is related to physical pathology, it may also be related
to psychological
factors.
From the Colorado
Sports and Spine Cenkr (Dr. Kaplan. Ms. Gdlis) and
the Departmenr
of Psychology.
University
of Colorado (Dr. Wurtele).
Colorado
Spnllgs.
Submitted for puhlicalion February 9. IYYS. Accepted in revised form July 17.
lYY.5.
No commercial
party havmg a dwecl or indwect mterest m rhe au+-r
matter
of this ankle has or wdl confer a henetir upon Ihe authors or upon any organi/atinn
with which the authors are associared.
Keorint reuuests to Iilenn M. Kaolan. PhD. Colorado Snorts and SDine Center.
162S’Med1cai Cenrer Point. Suite iO0. Colorado Springs.‘CO
X(tYo7:
0 lYY6 hy the American Congress of Krhahilitation
Medicine and the American
Academy of Physical Medicine and Kehabililation
0MMW39Y3/‘M7702-R4
I3$3.00/0
For example, depression is a factor that may affect a patient’s
performance on the FCE. The prevalence of depression among
pain patients is high.“” In general, depressed individuals may
have difficulty maintaining their usual levels of social activity,
show reduced interest in participating in hobbies, games, sports,
or social activities, and may exhibit psychomotor retardation.‘.
‘I’ Thus, being depressed may affect one’s ability to give maximal effort during the FCE.
Along with depression, chronic pain is likely to result in
anxiety.“.‘2 Anxiety is defined as the individual’s
appraisal of
a perceived threat.‘l Both personality and laboratory studies
provide support for the hypothesis that the more anxious a
person, the more intensely he or she perceives a painful stimu~us.“.‘~ Thus, high levels of anxiety may affect performance on
the FCE.
Physical therapists often acknowledge the importance of a
patient’s verbal description of his or her disability, yet these
subjective aspects are rarely quantified. As Dclitto’D noted, patients’ complaints of pain, disability, and difficulty are often
relegated to anecdotes documented during the evaluation. Evaluation of subjective disability may be useful in predicting a
patient’s ability to perform certain physical tasks. For example,
Triano and Schultz” found that subjective disability scores rclated significantly to such objective measures as absence of relaxation in hack muscles during flexion, mean trunk strength, and
trunk mobility. It may be useful to examine patients’ subjective
reports of disability as they relate to performance on the FCE.
Another cognitive variable is self-efficacy,”
I’) which reflects
the patient’s contidencc that he or she can perform specific
behaviors. Efficacy expectations influence the degree of effort
a patient with chronic pain will expend in various activities.
For example, Kores and collcagues2” found that chronic pain
patients with high self-efficacy scores after treatment demonstrated better overall functioning
and grcatcr reductions in
chronic illness behavior at the follow-up evaluation. Thus, there
is some support for a possible relationship between self-efficacy
and the degree of effort a patient expends during the FCE.
The FCE is often used for vocational planning and/or medicolegal case settlement,’ thus it is essential that the results be a
valid assessment of patients’ maximum functional abilities. Not
all patients exert maximal effort during the evaluation, however,
and thus the evaluator risks making false decisions about patients’ work-related abilities. Incorrect decisions regarding patients’ physical abilities can affect work recommendations,
impairment ratings, or medicolegal
settlements (ie, workers’
compensation or personal injury claims). Because of the importance of making correct decisions, we sought to determine if
there is a relationship between psychological
factors and FCE
performance. Compared with patients who give maximal effort,
it was predicted that patients who do not exert maximal effort
would be more depressed, anxious, and perceive themselves as
more disabled and less confident about their FCE performance
and their ability to return to work.
METHOD
Subjects
Subjects were 64 consecutive patients with low back pain (44
men, 20 women) who were referred for a Functional Capacity
Arch
Phys bled Rehabil
Vol77,
February
1996
162
FCE-PSYCHOLOGICAL
Evaluation at our Sports and Spine Center, an outpatient multidisciplinary physical therapy clinic. The mean age of the subjects was 39.1 years (range, 21 to 62 years). Mean time since
original injury was 18.9 months (range, 2 to 44 months). Patients had completed their physical therapy programs; therapy
had lasted an average of 6.4 months (range, 1 to 37 months).
Patients were out of work a mean of 14.9 months (range, 0
to 42 months). The majority (77%) were receiving Workers’
Compensation. Forty-one percent had undergone at least one
surgical procedure. Patients averaged 12.6 years of education
(range, 9 to 22 years), and 67% were married. Before their
injury, fewer than 8% earned less than $10,000 per year, 35%
earned between $10,000 to $19,999; 37% earned between
$20,000 to $29,999, and 20% earned $30,000 to $39,999. Their
previous occupations were clerical (2%), managerial (2%), professional (5%), construction (19%), maintenance (1 l%), technical (22%), and service (39%).
Procedure
Patients were recruited by a member of the research team
and given a description of the study. If a subject was interested
(only 2 patients were not), informed consent was obtained. Prior
to the FCE, each patient completed 5 questionnaires presented in
the following order: Demographic Information Questionnaire,
Beck Depression Inventory, Oswestry Low Back Pain Disability
Questionnaire, FCE Self-Efficacy scales, and the State-Trait
Anxiety Inventory. After completing the questionnaires, each
patient was administered the FCE by a registered physical therapist trained to conduct the evaluation. All therapists used the
same testing format, although as is characteristic of the field in
general,*’ inter-rater and test-retest reliability were not determined.
Measures
Beck Depression Inventory (BDZ). The BDI*’ is a 21-item
self-report inventory assessinga variety of dimensions of depressive symptomatology, including sleep disturbance, sexual
functioning, weight change, and anhedonia. Patients indicate
the extent of their depressive symptomatology using a 0 to 3
Likert scale, resulting in total scores ranging from 0 (no depressive symptoms) to 63 (extremely depressed). A score of 10
signifies at least mild depression.“,” Reliability and validity
data on the BDI are extensive.24
Oswestry Low Back Pain Disability Questionnaire.25 The
Oswestry measures patients’ subjective need for and effect of
pain medication, and assessesdifferent aspectsof disability affecting various functions of daily life (personal hygiene, walking, lifting, standing, sitting, sleeping, sex life, social life, and
traveling). All ten areasare believed to tap into the most relevant
problems suffered by patients with low back syndromes. Each
area contains six statements. Each statement describes a greater
degree of difficulty in that area than the preceding statement.
The patient marks the one statement in each area that describes
his or her perceived limitation most accurately. Each area is
scored on a 0 to 5 scale, with 5 representing the greatest disability. The scoresfor all areas are added together, giving a possible
subjective disability score of 50. The maximum of 50 points
would be obtained by patients who are either bed-bound or
exaggerating their symptoms, whereas a patient with no perceived disabilities would score 0 points. Two-day test-retest
reliability was .99 (25), and evidence of good internal consistency and concurrent validity exists.26
FCE Self-EfJicacy Scales. Patients’ confidence that they
could perform the FCE was measured using 4 questionnaire
items developed for this study (eg, “I feel I am ready to do my
Arch
Phys Med Rehabil
Vol77,
February
1666
FACTORS.
Kaplan
best on the FCE,” “I believe I will do well on the FCE”).
A single face-valid item was employed to determine patients’
readiness to return to work (“I am ready to return to work”).
Subjects indicated agreement or disagreement with these items
by circling the appropriate number on a 6-point Likert scale
ranging from 1 (strongly disagree) to 6 (strongly agree). Scores
on the FCE Self-Efficacy Scale can range from 4 to 24. For the
return-to-work item, scores can range from 1 to 6. Internal
reliability of the four-item scale was .82 (Cronbach’s alpha).
No evidence of the scale’s validity exists.
State-Trait Anxiety Znventory (STAZ). STAIz7 is divided
into state anxiety (A-State) and trait anxiety (A-Trait). Only AState scale scores were analyzed. State anxiety is measured by
20 short descriptive statements that the individual answers in
reference to how he or she feels at the moment. The answers
are recorded by indicating the intensity of the feeling on a 1 to
4 scale (1 = not at all, 2 = somewhat, 3 = moderately so, 4
= very much so). Scores can range from 20 to 80. Although
STAI-State has low test-retest reliability (.54), it has good internal consistency, content, concurrent, and construct validity.27
Functional Capacity Evaluation (FCE). The FCE is a set
of evaluation procedures used to determine a person’s ability
to perform physical tasks. Physical therapists at our center use
a protocol that includes 3 standard tests recommended by Blankenship’ to determine whether a patient is exerting maximal
effort during the evaluation: Waddell’s signs,28Grip Strength,”
and Coefficient of Variation.” Waddell’s signs are ratings done
by the physical therapist based on nonorganic signs, including
tenderness, simulation, distraction, and overreaction. A finding
of 3 or more positive signs during an evaluation is clinically
significant.’ Grip Strength was measured three times (beginning,
middle, and end of FCE test) in 5 test positions using a hand
dynamometer. With maximal effort, scores form a bell-shaped
curve, whereas non-bell-shaped curves indicate submaximal
effort. Possible range of scores was 0 to 6, with scores of 3 or
more considered submaximal. Coefficient of Variation (CV)
evaluates static strength (push, pull, arm pull, and leg pull),
and is calculated using the following formula: CV = Standard
Deviation + the Mean x 100. A positive score was given for
each CV over 15% resulting in scoresranging from 0 to 6, with
CV scores of 3 or more considered submaximal. In this study,
subjects were classified as giving submaximal effort if they
displayed 3 or more Waddell’s signs, if they had 3 or more
incorrect Grip curves, or if they had 3 or more CVs over 15%.
Using this formula, 21 of the 64 patients (33%) met the criteria
for submaximal performance. Of the 21, 15 had submaximal
effort on 1 test, 4 on 2 tests, and 2 on all 3 tests.
RESULTS
Before analysis, data were examined for accuracy of data
entry, missing values, outliers, and fit between distributions and
the assumptions of multivariate analysis.
Table 1 lists the demographic characteristics of the 2 patient
groups. Comparisons between groups showed no significant differences in gender, age, income, occupation, duration of illness
or physical therapy, how long patients had been out of work,
or whether they were receiving Workers’ Compensation. The
2 groups differed only on the number of previous surgeries,
F(1,60) = 4.56, p < .05, with the submaximal effort group
having had more surgeries compared with the maximal effort
group.
A multivariate analysis of variance (MANOVA) was performed to assessthe differences between the 2 groups on BDI,
Oswestry, FCE Self-Efficacy, Return to Work, and STAI scores.
The MANOVA was significant, Wilks’ lambda = .742, F(5,58)
= 4.02, p < .Ol, with the univariate tests for Oswestry, F( 1,62)
FCE-PSYCHOLOGICAL
= 14.89, p < ,001, FCE Self-Efficacy,
F( 1,62) = 4.27, p <
.OS, Return to Work, F(l,62)
= 9.63, p < .Ol. and STAI,
F( 1.62) = 7.26, p < .Ol, all being significant. The univariate
test for BDI approached significance, F( 1.62) = 3.33, p = .07.
Patients who gave submaximal effort had higher BDI, Oswestry,
and STAI scores, and lower FCE Self-Efficacy and Return to
Work scores (table 2).
DISCUSSION
Findings from this study support our prediction that psychological factors are related to performance on the FCE. Even with
a small sample, the results provide evidence for the relationship
between subjective disability, depression, anxiety, self-efficacy,
and patients’ performances on the FCE. Compared with patients
who gave maximal effort during the FCE, patients who did not
exert maximal effort on at least one of the three FCE subtests
reported more depressive symptomatology,
anxiety, and pcrceived themselves as more disabled. They also reported lower
expectations for performing
well on the FCE and rated themselves as less ready to return 10 work. Patients who perceive
themselves as more depressed, anxious, disabled, or lower in
self-efficacy are at risk for not giving maximal effort during the
FCE. Thus, the evaluation process could be affected as it relates
to work recommendations,
impairment ratings, or medicolegal
settlements.
Some limitations of this study need to bc noted, with concomitant suggestions for future research. Given the design, it is
not possible to determine a cause and effect relation between
psychological factors and submaximal effort. Whether psychological factors influence physical performance, physical performance influences psychological factors, or both are affected by
a third factor (eg, extent of injury) are questions that need
further exploration. Also, because all data were collected from
patients at a single outpatient physical therapy clinic, the results
are relevant only for that population. In addition, the use of the 3
tests to identify submaximal effort (ie, Waddell’s Grip Strength,
Coefficient of Variation) is unique to this study and warrants
Table
1: Demographic
Characteristics
Variable
Gender n f%)
Men
Women
Age (n = 64)
Mean (SD) fvr)
Income n 1%) in = 51)
w-9.999
$10-19.999
$20-29.999
Go-39;999
Occupation
n (%) In = 62)
Clerical
Managerial
Professional
Construction
Maintenance
Technical
Service
Duration
of illness (n - 48)
Mean (SD) fmo)
Duration
of physical
therapy
(n - 57)
Mean (SD) fmo)
How long out of work fn - 62)
Mean (SD) fmo)
Receiving
workers’
compensation
(n - 64)
Yes n (%)
Number
of surgeries
(n = 62)
Mean (SD)
lp
-: .05
Performance
SubmaxImal
Performance
20 (65)
15 135)
16 (76)
5 (24)
39.33
(8.54)
38.62 (9.93)
3
14
10
7
(8.8)
(41.2)
(29.4)
(20.6)
1
4
9
3
(5.9)
(23.5)
(52.9)
(17.6)
0
1
2
7
6
9
17
(0.0)
(2.4)
(4.8)
(16.7)
(14.3)
(21.4)
(40.5)
1
0
1
5
1
5
7
(5.0)
(0.0)
(5.0)
(25.0)
15.01
(25.0)
(35.0)
17.42 (16.57)
22.27
(13.11)
6.59 (7.07)
5.94 (6.58)
13.67 (15.381
17.55 (11.60)
FACTORS,
Table
14 (66.7)
1.24 (1.25)’
2.15 (2.111’
2: Means
BDI
(range O-63)
Oswestry
(range O-50)
FCE Self-Efficacy
(range 4-24)
Ready to Return
(range l-6)
STAlLState
(range 20-80)
(SDs) for Dependent
Maximal Performance
in 43)
Variable
Measures
Submaximal
in
10.09
(6.83)
19.61
(7.19)
19.51
(4.12)
3.30
(1.95)
40.86
(10.44)
to Work
Performance
21)
13.19
(5.28)
26.71
(6.33)
17.05
(5.15)
1.86
(1.24)
48.29
(10.16)
replication. Finally, future studies with larger samples may explore the sensitivity and specificity of the psychological
tests
for predicting submaximal effort.
The most obvious implication of our findings is that professionals who assess patients with low back pain need lo consider
how psychological
factors can affect a patient’s performance
during the FCE. It is not uncommon for patients to be administered an FCE at the request of physicians and/or at the conclusion of a physical therapy program. Just because patient5 have
completed their physical therapy or they are requested to take
the FCE does not mean that they are ready to take the FCE.
We recommend that before patients arc scheduled to take the
FCE, psychological
tests and the Oswestry questionnaire
be.
administered to determine readiness for the FCE. If patients
show elevations on these scales, then psychological counseling
should he prescribed prior to the FCE. Counseling to address
depression, anxiety, self-efficacy, and perceived disability is
important with chronic pain patients and has been shown to hc
effective in dealing with these psychological issues.“,” Facilitating psychological in addition to physical readiness may result
in a better estimate of the patient’s maximum functional abilities.
Acknowledgments:
Special
thanks
to Sue Jardon.
Peggy Pease,
and Mary Watt, Physical Therapists, for their assistance during data
collection.
Constructive
comments
from Alan Jette on an earlier version
of this article were grcarly
appreciated.
4.
5.
6.
7.
35 (81.4)
163
Kaplan
8.
9.
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