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e OHSIG has breaking news! APTA obtained a 5/26/2018
letter of clarification from OSHA to establish that all forms of
soft tissue massage performed by physical therapy professionals
are considered first aid for record keeping purposes. is was a
collaborative effort by our OHSIG, APTA Government Affairs,
and the Private Practice Section. I want to acknowledge the vol-
unteer contribution by 3 OHSIG members who flew in to meet
with OSHA officials: Lorena Payne, Drew Blossen, and Curt
DeWeeze. is letter supports direct contracting by physical thera-
pists with the industry. For more information about this initia-
tive, see http://www.apta.org/PTinMotion/News/2019/06/05/
OSHAMassagePTs.
Last month, we got a fantastic response to the launch of our
mentorship program that is led by our Communications Chair,
Caroline Furtak. Our Work Rehab CPG Writing Team led by
Lorena Payne is now wrapping up the quality review of additional
articles identified in an updated literature search. We have launched
a new subcommittee to review Current Concepts in Regulatory
Compliance for occupational health. e OHSIG is forming two
new standing committee's for Practice/Reimbursement and Mem-
bership. If you are interested in serving on either of these commit-
tees, please contact any member of our nominating committee.
Next, I would like to put out a call for OHSIG members to
share best practice examples from your state on our closed Face-
book page that we can leverage to improve the practice environ-
ment for physical therapy professionals in occupational health.
For example, did you know that Washington State Labor and
Industries created special codes for functional capacity evaluations
(FCEs), telehealth conferences, and functional job analyses? Wash-
ington State has established quality expectations for physical and
occupational therapists when performing a complex functional
capacity evaluation. ey have also designed a useful functional
job analysis form that may be downloaded from their website at
the following link: https://www.lni.wa.gov/ClaimsIns/Voc/Back-
ToWork/JobAnalysis/default.asp. e most exciting feature of the
Washington State Job Analysis form is that the last page contains
a release to return the worker to full duty or back to work with
restrictions that may be certified by the treating physical therapist/
occupational therapist or an independent FCE Examiner!
Finally, in this issue of Orthopaedic Physical erapy Practice,
the OHSIG is pleased to introduce a review article about the Ches-
ter Step Test (CST). Mindy Renfro, PT, DPT, PhD, and her physi-
cal therapy students at Touro University Nevada volunteered to
review the Chester Step Test for inclusion in our PTNow database
of tests and measures after a suggestion was made to include func-
tional capacity performance measures in PTNow that are relevant
to occupational health practice. is review article led by “Team
Touro” is the first “fruit” to emerge from this request. It was truly
a pleasure to collaborate with Mindy and her group of students on
this article. You will discover that the CST has some advantages
over self-paced walk tests to help bridge the gap between wellness
and rehabilitation. Enjoy!
The Chester Step Test: A Graded
Performance Measure of Aerobic
Capacity for Physical Therapy
Mindy Oxman Renfro, PT, DPT, PhD1; Rick Wickstrom, PT,
DPT, CPE2; Emigdio Angeles, SPT1; Colton Cardon, SPT1;
Madison Ho, SPT1; Andrea Valdez, SPT1; Dallan Valle, SPT1
1
Touro Univ. Nevada, School of Physical erapy, Henderson, NV
2WorkAbility Systems, Inc., West Chester, OH
BACKGROUND
In rehabilitation, an array of factors must be considered to
ensure that interventions prescribed lead to desired outcomes. One
factor that is crucial to evaluation and progression of physical ther-
apy clients is ensuring that appropriate tasks are prescribed to chal-
lenge the fitness of cardiorespiratory and musculoskeletal systems.
Failing to challenge a client’s abilities leads to inadequate gains,
while overworking may lead to fatigue and injury.1 A hot topic in
rehabilitation practice is finding a quick, efficient, and low-cost
test of cardiorespiratory fitness (CRF) that is reliable and valid.
Low CRF is a stronger predictor of all-cause mortality and cardio-
vascular events than risk factors such as physical inactivity, obesity,
smoking, hypertension, abnormal lipids, and diabetes mellitus.2,3
Maximum oxygen consumption (VO2max) is often estimated less
costly submaximal exercise tests to prescribe suitable physical activ-
ity or classify fitness based on normative results for healthy adults.4
e Chester Step Test (CST) is a simple, submaximal test of
aerobic capacity that was originally designed by Kevin Sykes to
predict maximal aerobic power, based on the heart rate responses
to progressive workloads.5 e CST is a versatile step test that
has been used in a broad range of fitness and clinical applications
that include (1) tracking of changes in aerobic fitness in healthy
adults,6 (2) assessing of fitness-for-duty of disaster deployment
personnel,7 and (3) assessing of exercise capacity in patients with
chronic lung disease.8 e CST protocol allows the examiner to
choose a suitable fixed step height that ranges from 15 cm (6")
to 30 cm (12"), based on factors such as age, functional capacity,
activity level, height, and obesity. e subject steps on and off the
step platform (Figure 1) in cadence with a metronome beat that
is increased by 5 steps per minute at each 2-minute stage (15, 20,
25, 30, and 35 steps per minute). Heart rate (HR) and rating of
perceived exertion (RPE) are measured at the end of each stage
to assess the participant’s response to each incremental workload.
Step pace is increased with each stage, until individuals reach 80%
of their predicted HR maximum (based on 220-age), reports an
RPE ≥ 14 using the 6 to 20 Borg scale,9 or completes all 5 stages
in a 10-minute period. e CST uses the ACSM stair-stepping
equation to estimate the workload oxygen cost (mlO2/kg/min) for
the step height and pace at each stage.10 A visual or statistical line
of best fit is drawn using datapoints for HR (y-axis) and workload
(x-axis) that is extended up to maximum HR to estimate maxi-
mum aerobic capacity (mlO2/kg/min) from the x-axis.5
PRESIDENT'S MESSAGE
Rick Wickstrom, PT, DPT, CPE
172
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Reprinted from Renfro MO, Wickstrom R, Angeles E, et al. The Chester step test: a graded performance measure of aerobic capacity
for physical therapy. Orthop Phys Ther Practice. 2019;31(3):172-178.
Figure 1. Chester Step Test administration.
PURPOSE
e purpose of this literature review is to assess the validity
and reliability of the CST as a tool for assessing aerobic capacity of
individuals during physical therapy care. is review was requested
to provide useful information about CST for practicing clinicians
in the PTNow website of Tests and Measures of the American
Physical erapy Association (APTA).
METHODS
Search Strategy and Selection Criteria
e literature search was conducted in the databases CINAHL,
Cochrane Library, Embase, Google Scholar, PTNow, PubMed,
Scopus, and SPORTDiscus. e search terms used included
“Chester step test”, Chester step test, “Chester step test” AND
VO2max AND aerobic capacity AND cardiorespiratory fitness.
e searches were completed in January 2019 by five reviewers
(EA, CC, MH, AV, and DV). Search filters were used with Google
Scholar and PTNow, which limited results to more recent litera-
ture from 2010-2019 and 2003-2019, respectively. e reviewers
independently screened the titles and abstracts of the acquired arti-
cles to determine if they met the inclusion and exclusion criteria.
After duplicate articles were extracted and inclusion and exclusion
criteria were assessed, 22 relevant articles remained. Studies were
included if (1) they analyzed the validity or reliability of the CST,
(2) access was available to the full text article, (3) subjects were
adults age 18+, and (4) the article was published in English in a
peer-reviewed journal. Articles were excluded if the CST was not
studied. Reference lists of included articles were also screened for
other applicable articles.
Quality Assessment
A two-step process was used to appraise the selected articles.
e appraisal tool of 11 questions from Evidence Based Physical
erapy by Fetters and Tilson11 was used to assess article quality and
applicability. e total score for each article varied depending on
the number of questions applicable to the article. If a question was
inapplicable, it was removed from the total score. erefore, some
articles were rated out of a total score of 11 and other articles were
rated out of a total score of less than 11. Each article was appraised
by two independent reviewers, who then compared scores. Dis-
agreements between scores were resolved through consensus and a
third-party adjudication. Articles that did not fit inclusion criteria
were removed.
FINDINGS
irteen articles (Table 1) were identified as appropriate based
on inclusion and exclusion criteria.5,12-23 ese articles were high
quality based on the reviewers’ appraisal and the ratings ranged
from 62.5% to 100%. e samples described in the articles
involved various populations, such as healthy adults, university
students, steel workers, and patients with lung diseases. Sample
sizes in the studies ranged from 13 to 171 subjects. e studies
were conducted internationally in countries including the United
Kingdom, Brazil, Australia, United States, and Iran.
Step heights used in these studies for the CST ranged from
17 cm (7") to 30 cm (12"). In studies of patients with chronic
obstructive pulmonary disease (COPD) or lung diseases, the step
height was lowered to 17 cm (7")20 or 20 cm (8").12,14-16,19 A 30 cm
(12") step height was used in studies looking at healthy subjects or
university students.5,10
Criteria for stopping the test varied somewhat between studies:
• When the subject obtained 80% to 90% of age predicted
HRmax5,13,17-18, 20,23
• When SpO2 levels dropped below 84% to 88%14,19
• e subject was unable to maintain pace with the metro-
nome12,14,15,19,20
• e subject reported symptoms of dyspnea or fatigue12,14,15,19,20
• One study20 used a different equation to predict maximum
HR = 210-(0.65*age)
If a subject experienced any of the above criteria, then the test
was terminated, and the subject would not continue onto the next
stage of the CST. Subjects who were able to complete all 5 stages
of the CST were tested for a maximum duration of 10 minutes.
Many of the studies found the CST to be a reliable tool for
assessing CRF.5,13-15,23 Sykes and Roberts,5 Buckley et al,13 and
Saremi et al23 concluded that the CST is a reliable test for assessing
aerobic capacity among healthy subjects. e CST has been found
to be reliable for assessing aerobic capacity in patients with bron-
chiectasis and COPD.14,15
In addition to assessing CRF, the CST can be used to assess
functional performance and fitness levels.18-20 Several studies found
that the CST can assess functional capacity in patients with COPD
and acute lung diseases.19,20 Karloh et al20 found that CST was sig-
nificantly correlated with TShuttle (r=0.67) and the Six Minute
Walk Test (6MWT) (r=0.83), which require more space to admin-
ister. Several studies used the total number of steps completed on
the CST at a lower 20 cm (8") step height as the main outcome
measure for COPD patients.12,14,16,19 Total steps were found to be
highly reliable and correlated with 6MWT results. Several studies
evaluated a modified pacing protocol to reduce the initial pace to
10 steps per minute and provide for a more gradual progression
of 1 step every 30 seconds with COPD patients.12,14-16 Gray et al18
found that male steel workers with lower CRF based on the CST
were more likely to have greater cardiovascular disease risk. Addi-
tionally, this study provides evidence that the CST has good prog-
nostic value for prediction of cardiovascular disease.18
173
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Table 1. Studies Included in this Review
Study Reference
Andrade
et al 2012
12
Buckley
et al 2003
13
Camargo
et al 2011
14
Camargo
et al 2013
15
Dal Corso S
et al 2013
16
Elliot D
et al 2006
17
Gray
et al 2016
18
Jose and Dal
Corso 2016
19
Karloh
et al 2013
20
Sample [Country]
32 subjects with COPD
(ages 67±8) with COPD
[Brazil]
13 healthy university
students (age 22.4±4.6, 7
males) [UK]
17 patients (6 men, age
52±17) with bronchiectasis
(BCT) [Brazil]
17 patients with
bronchiectasis [Brazil]
34 patients (age 67±9) with
COPD [Brazil]
25 healthy subjects [UK]
81 male steel workers [UK]
77 patients with acute lung
diseases and 20 healthy
subjects [Brazil]
10 patients with COPD
and 10 healthy sedentary
subjects (age 63±7 [Brazil]
Step Height
20 cm
30 cm
20 cm
20 cm
20 cm
Not specified
Not specified
20 cm
17 cm
CST Procedure/Modifications
a. Main outcome was NOS performed.
b. Stopped test when participant was unable
to maintain step pace, dyspnea, or fatigue.
c. Substituted Borg 0-10 category ratio scale
to assess dyspnea and lower limb fatigue.
Only change was that end point of test was
increased to 90% predicted HRmax and/or
RPE 17.
a. Main outcome was NOS performed.
b. Stopped test when participant was unable
to maintain step rate, SpO
2
<88%,
dyspnea, or fatigue.
c. Substituted Borg 0-10 category ratio scale
to assess dyspnea and lower limb fatigue.
a. Main outcome was NOS performed.
b. Stopped test when participant was unable
to maintain step pace, SpO
2
<88%,
dyspnea, or fatigue.
c. Substituted Borg 0-10 category ratio scale
to assess dyspnea and lower limb fatigue.
a. Main outcome: Vertical distance calculates
by multiplying step height by NOS.
b. Symptom-limited IST is a modification to
CST with lower initial step rate (10 steps/
min) and pace increased by 1 step/min
every 30 sec. Allowed handrail. Stopped
with intolerable dyspnea, fatigue, or pace.
c. Substituted Borg 0-10 category ratio scale
to assess dyspnea and lower limb fatigue.
CST performed with active and passive arm
action on separate occasions.
a. Main outcome: NOS.
b. Substituted Borg 0-10 category ratio scale.
c. Test ended when participant had dyspnea,
fatigue, unable to maintain pace, or SpO
2
< 84%.
a. Test stopped when subject could not
keep pace, showed limiting symptoms, or
reached 90% predicted HRmax, calculated
with 210-(0.65*age).
b. Substituted Borg 0-10 category ratio scale
to assess dyspnea.
Reliability
MIST and CST showed
similar cardiopulmonary
responses and exertion effort at
peak exercise.
CST Test-retest HR (ICC
0.88), SpO
2
% (ICC 0.91),
NOS (0.99).
CST is reliable for test-retest
assessment of aerobic fitness
in healthy young adults.
Recommended a practice trial
to improve RPE and %HRmax
correlation and not using
datapoints for Stage 1.
Test-retest for NOS highly
reproducible (66±41 steps,
68±41 steps)
CST and MIST were reliable
in BCT patients. Test-retest
reliability for CST was: HR
(ICC 0.88), SpO
2
% (ICC
0.91), and NOS (0.99). Test-
retest means for NOS was
similar for CST (124±65 and
125±67) and MIST (158±83
and 156±76). No difference
between MIST and CST for
cardiopulmonary responses and
exertion at peak exercise level.
IST test-retest was highly
reproducible 2-5 days later
with NOS (ICC 0.98),
VO2 (ICC 0.99), VE (ICC
0.97), HR (ICC 0.92), SpO
2
(ICC 0.96). Most had better
performance on IST2.
Not stated.
N/A
N/A
174
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Validity
Exercise tolerance (test time) higher in MIST (6.1±2.2 min) compared
to CST (8.8±2.8 min). Similar correlation for NOS with 6MWT
distance for CST NOS (r=0.72) and MIST (r=0.80). Similar correlation
for NOS with FEV1 for CST (r=0.62) and MIST (r=0.66).
Questionable validity in predicting VO
2
max. Estimated vs. actual
maximum VO
2
show errors ranging from 11 to 17%. Age-estimated
HRmax significantly overestimated actual HRmax by a mean of 5 beats/
min. CST1 underestimated actual VO
2
max by 2.8 ml/kg/min (p=0.006)
and CST2 by 1.6ml/kg/min (not significant).
NOS correlates with FEV1 (r=0.43), 6MWT distance (r=0.60), and
incremental cycling test (r=0.69).
CST compared with 6MWT and MIST with lower initial step rate and
pace increased by 1 step/min every 30 sec. Better exercise tolerance (test
time) for MIST (8.6±3.0 min) than for CST (6.0±2.2 min). Similar
correlation with 6MWT distance for CST NOS (r=0.72) and MIST
(r=0.80). Similar correlation for CST NOS with FEV1 for CST (r=0.62)
and MIST (r=0.66).
NOS and weight explained 80% of variance in peak V02. IST elicits
maximal cardiopulmonary and metabolic responses and is well-tolerated.
Peak VO
2
was higher for IST1 and IST2 (1.19±0.39 L, 1.20±0.40 L)
than cycling (1.07±0.35 L) with no difference in ventilation, HR, or
RPE responses.
Active arm action during CST had no significant impact on predicted
VO
2
max, but did increase Heart Rate by about 7 beats/min across all stages.
CST can be used for cardiorespiratory fitness testing for prediction of
cardiovascular disease. CRF level of 34.5 ml/kg/min identified persons
over QRISK2 threshold with sensitivity (0.80) and specificity (0.687).
Five times higher cardiovascular risk for Average-Below Average vs.
Good-Excellent fitness classification.
Number of steps of CST and MIST were similarly correlated with length
of hospitalization, lung function, dyspnea, and 6MWT (r=0.59, r=0.64).
CST and MIST are safe and can be used to assess functional capacity in
patients hospitalized for acute lung diseases.
CST is valid for assessment of functional capacity of COPD patients
and distinguished between performances of COPD patients and healthy
subjects. CST correlated with TShuttle (r=0.67) and 6MWT (r=0.83).
Several studies have evaluated the validity of the CST in esti-
mating VO2max.5,13,23 e study by Sykes and Roberts5 found
there is a high correlation between VO2max and the CST; there-
fore, this suggests that the CST can be used to estimate VO2max.
Additionally, Saremi et al23 found that the CST is a valid test for
estimating cardiorespiratory capacity among university students
that was significantly correlated (r=0.868) with actual VO2max as
calculated by the Astrand-rhyming cycle ergometer test. Buckley
et al13 used the same CST procedure as the one outlined in Sykes
and Roberts’s5 study, with the only difference being that Buckley et
al13 changed the end point of the test to 90% of predicted HRmax
and/or RPE 17 (out of 20) to get vital sign measurements for
VO2max estimation from as many stages of the CST as possible.
Despite using the same CST procedure, Buckley et al13 found the
validity of the CST to estimate VO2max to be questionable. ese
two studies demonstrate conflicting evidence regarding the valid-
ity of the CST.5,13
CLINICAL RELEVANCE
e reliability, validity, versatility, and low cost of the CST
makes it an attractive option for many clinical settings. e CST
provides many advantages over other step tests6 and self-paced
walking tests due to the option to adjust the step height based
on an individual’s fitness, use of a small evaluation space, external
pacing, and short completion time. e CST can be performed
safely in a small clinic room, at home, the workplace, and other
community settings.
Many studies used to establish the reliability and validity of the
CST were performed on young, healthy participants who were able
to tolerate the intensity of the 30 cm (12") step. Physical thera-
pists performing the CST must use sound clinical judgment when
deciding what step height and increment of cadence to use with
each patient. ree modifications to accommodate less-fit popula-
tions include:
1. Step Height: Lower steps of 15 cm (6") and 20 cm (8") may
be used to provide accurate data while increasing patient
safety for patients in hospital settings or those with chronic
diseases. A higher step of 40 cm (16") may provide a greater
physical challenge for fitter athletes. A much lower step of 10
cm (4") would be an alternative to consider to accommodate
patients with more severe obesity, lower extremity impair-
ments, or cardiopulmonary impairments.
2. Testing Intervals: One concern with the CST in less athletic
individuals is the rigor of keeping up with the two-minute
phases. Reducing these 5 two-minute phases into 10 one-
minute phases is less strenuous on those with respiratory is-
sues or other frailties. is would also make findings more
sensitive, giving better estimates of CRF or highest workload
completed.15
3. Activity Prescription: e CST is an incremental functional
performance test of aerobic capacity that may be used to as-
sess readiness for physical activity.19-20 e predicted maxi-
mum VO2 and peak workload level that was performed on
the CST may be compared to representative aerobic demands
of specific occupation or lifestyle tasks that are contained in
ACSM’s Guidelines for Exercise Testing and Prescription.4
For example, Table 1.1 in the ACSM Guidelines reports that
the metabolic equivalent for mowing the grass with a push
mower is 5.5 METs. Table 2 may be used to look up the peak
workload achieved by a client, based on the highest accept-
(Continued on page 176)
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Table 1. Studies Included in this Review (continued from page 175)
Study Reference
Lau HM,
et al 2005
21
Lau HM, Ng GY
et al. 2005
22
Saremi
et al
23
Sykes and
Roberts
5
Sample [Country]
171 patients (ages 37±12,
60 men) with SARS
[Australia]
133 SARS patients (62
Controls: age 38.3±11.2
n=62, 71 Exercise: age
35.9±9.3)
63 (age 20.17±1.8, 29
male) university students
[Iran]
68 healthy subjects [UK]
Step Height
Not stated
Not stated
Not stated
30 cm
CST Procedure/Modifications
None stated.
None stated.
Standard protocol.
Reliability
N/A
N/A
Stepped to metronome
at 15 steps/min with step
rate increasing by 5 steps/
min every 2 min. Max test
duration 10 min. Test ended
when subject showed signs of
over-exhaustion or reached
85% HRmax. Step height
unspecified.
Mean difference of -0.7ml/kg/
min between sessions.
Abbreviations: CST, Chester step test; COPD, chronic obstructive pulmonary disease; NOS, number of steps; SpO2, peripheral capillary oxygen consumption;
MIST, modified incremental step test; HR, heart rate: ICC, interclass coefficient; 6MWT, 6 minute walk test; FEV1, forced expiratory volume;
HRmax, maximum heart rate; RPE, rate of perceived exertion; VO2max, maximum oxygen consumption; BCT, bronchiectasis; VO2, oxygen consumption;
VE,ventilatory efficiency; CRF, cardiorespiratory fitness; QRISK2, cardiovascular disease risk algorithm; SARS, Severe Acute Respiratory Syndrome
able pace completed for a given step height. A client who
only achieves a peak workload of 3.94 METs for stepping at
15 steps per minute to a 20 cm (8-in) step platform is not
ready to perform this task, but could be cleared to perform
light household chores that require 2.0-2.5 METs.
4. Heart Rate Effects Due to Age, Medication, or Pain: e
220-age method to estimate maximum HR has been shown
to underestimate VO2max results for older adults.24 Gellish
et al25 recommended 220 – (0.7 * age) to estimate maximum
HR for healthy adults. One of the limitations with using HR
for extrapolation is that medications such as betablockers
may lower the HR response, resulting in overprediction of
aerobic capacity. Brauner et al26 recommended 164 – (0.7 *
age) to estimate maximum HR for patients with coronary ar-
tery disease on beta-blocker medications. Another challenge
for orthopaedic patients is that pain may not allow a suf-
ficient HR response for a valid prediction of VO2max. While
medications or musculoskeletal symptoms may invalidate
prediction of VO2max, workload at the highest stage com-
pleted and HR/RPE responses still provides useful functional
performance data to justify therapy progress or readiness for
physical activity.
It is recommended that the test be performed as instructed
whenever possible. Deviations from the CST’s original protocol5
may compromise its validity and reliability. However, researchers
have shown that modifying the workload progression of the CST
with COPD patients resulted in equivalent cardiopulmonary stress
at exertion at the peak exercise level.12 is validates the use of
functional performance outcomes such as total number of steps
or peak workload completed to assess improvements in CRF and
Table 2. Workloads for Step Test in METs at Different
Combinations of Step Pace and Height
10
Step Height
Step Pace 10cm (4in) 20cm (8in) 30cm (12in)
35 5.43 7.86 10.3
32.5 5.12 7.37 9.63
30 4.80 6.88 8.97
27.5 4.48 6.39 8.3
25 4.17 5.90 7.64
22.5 3.85 5.41 6.98
20 3.53 4.92 6.31
17.5 3.22 4.43 5.65
15 2.90 3.94 4.98
12.5 2.58 3.45 4.32
10 2.27 2.96 3.66
(steps/min) METs METs METs
Workload METs = [3.5 + (0.2 x steps/min) +
(1.33 x 1.8 x Step Height (cm) x 0.01cm/m x steps/min)]/3.5
weight-bearing exercise tolerance. Figure 2 illustrates how modifi-
cation of step height may be used to provide a different workload
progression for clients based on whether recent physical activity
level was vigorous, moderate, or inactive. Choosing a suitable step
height allows the clinician a simple and inexpensive way for a clini-
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Validity
Values of predicted maximum VO
2
(mL*kg-1*min-1) lower for
significantly lower for SARS patients than normative data (43 Men:
38.47±7.39, 91 women: 36.12±7.42). 41% completed all 5 levels of
CST.
Randomized Controlled Trial revealed significant improvement for
exercise group compared to control for CST predicted VO
2
(3.6±5.4),
six-minute walk distance, hand grip, curl-up, and push-up.
CST is a valid and reliable test for estimating cardiorespiratory capacity
among university students.
High overall correlation (r=0.092) for predicted with directly measured
VO
2
max from a graded treadmill test with a standard error of predicted
CST1 of ±3.9 ml/kg/min.
Abbreviations: CST, Chester step test; COPD, chronic obstructive pulmonary disease; NOS, number of steps; SpO2, peripheral capillary oxygen consumption;
MIST, modified incremental step test; HR, heart rate: ICC, interclass coefficient; 6MWT, 6 minute walk test; FEV1, forced expiratory volume;
HRmax, maximum heart rate; RPE, rate of perceived exertion; VO2max, maximum oxygen consumption; BCT, bronchiectasis; VO2, oxygen consumption;
VE,ventilatory efficiency; CRF, cardiorespiratory fitness; QRISK2, cardiovascular disease risk algorithm; SARS, Severe Acute Respiratory Syndrome
may be used as a functional performance test with patients that
have orthopaedic and other health conditions, ranging from acute
cardiopulmonary disease to high-functioning, physically active
individuals. e CST allows the clinician to safely establish base-
line CRF and observe how the patient tolerates and responds to
increasing physical activity.
e reliability and validity of the CST to estimate VO2max
rely on normal HR response to increasing workloads. Common
cardiorespiratory medications such as beta-blockers will inhibit
the patient's heart rate response to increasing workload. is may
limit their performance and cause the CST calculations to under-
estimate maximum cardiorespiratory function. Additionally, the
performance of patients with lower extremity musculoskeletal
impairments may reach mechanical limitations prior to their max-
imum aerobic capabilities. is may lead to the underestimation
of their actual cardiorespiratory capacity. For this reason, clinicians
must adjust the test to appropriately accommodate these variables.
e available literature on the CST indicates a number of pos-
sible areas for future research. ese include validation of the CST
as a measure of/with:
• specific functional capacities,
• modifications with a variety of patient populations,
• using the highest tolerated workload as an outcome measure
of performance, and
• guidelines for concluding the test.
is literature review concludes that the CST is a valid and
reliable clinical measure of aerobic capacity for physical therapists
to use for a wide range of patients and settings. Its future study and
expansion will benefit the profession as we investigate and establish
the best tests and measures for evidence-based clinical practice.
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CONCLUSIONS
is review of the literature supports the use of the CST as a
reliable and valid measure of functional performance for physical
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relevant alternative to the 6MWT. It also suggests that the CST
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Rick Wickstom, President 2019-2022 rick@workability.us
Brian Murphy, Vice President/ Educaon Chair 2017-2020 Brian.Murphy@ResultsPhysiotherapy.com
Frances Kistner, Research Chair 2014-2020 frances.kistner@mcphs.edu
Caroline Furtak, Communicaons Chair 2017-2020 ckfurtak@gmail.com
Trisha Perry, Nominang Commiee Chair 2017-2020 trishaperry@n-o-v-a.com
Kae McBee, Nominang Commiee Member 2018-2021 KMcBee@selectmedical.com
Michelle Despres, Nominang Commiee Member 2019-2022 michelle_despres@onecallcm.com
OCCUPATIONAL HEALTH LEADERSHIP
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