Cardiorespiratory Fitness and Functional Capacity Assessed by
the 20-Meter Shuttle Walking Test in Patients With Coronary
Artery Disease
Mathieu Gayda, PhD, Dominique Choquet, MD, Abdou Temfemo, PhD, Saı ¨d Ahmaı ¨di, PhD
ABSTRACT. Gayda M, Choquet D, Temfemo A, Ahmaı ¨di
S. Cardiorespiratory fitness and functional capacity assessed by
the 20-meter shuttle walking test in patients with coronary
artery disease. Arch Phys Med Rehabil 2003;84:1012-6.
Objective: To validate the 20-meter shuttle walking test
(20MST) in the assessment of maximal oxygen consumption
(V
˙
O
2
max) and maximal speed in patients with coronary artery
disease (CAD).
Design: Single-sample validity study.
Setting: Cardiac rehabilitation service in France.
Participants: Seventeen men with CAD.
Interventions: Subjects underwent a symptom-limited
treadmill test (SLTT) in a laboratory, with a speed starting at
2.5km/h and increasing by 0.5km/h every minute, and per-
formed an adapted 20MST in a corridor, with a speed starting
at 3km/h and increasing by 1km/h every minute until exhaus-
tion.
Main Outcome Measures: V
˙
O
2
measured during the
20MST with the Cosmed K2 telemetric gas analyzer (K2 V
˙
O
2
),
estimated V
˙
O
2
calculated by the Le ´ger equation (Le ´ger V
˙
O
2
)
from the maximal speed obtained during the 20MST, and V
˙
O
2
measured during the SLTT (SLTT V
˙
O
2
). Maximal speeds at-
tained on the treadmill and on the 20MST were also compared.
Results: A significant (P.0001) difference was observed
between the Le ´ger estimate of V
˙
O
2
and those of K2 V
˙
O
2
and
SLTT V
˙
O
2
(mean standard deviation, 12.285.90mL
min
-1
kg
-1
vs 23.047.17 and 22.566.29mLmin
-1
kg
-1
).
No difference was found between the treadmill and the 20MST
maximal speeds (6.730.91km/h, 6.781.23km/h, respectively).
Measured with the Cosmed K2, a significant relationship existed
between V
˙
O
2
and each speed level (r=.95, P.0001; V
˙
O
2
=4.24
speed–7.37, standard estimation error=2.29mLmin
-1
kg
-1
).
Conclusion: Maximal V
˙
O
2
and maximal speed measured on
the treadmill did not differ significantly from those obtained on
the 20MST. The current 20MST equation (Le ´ger equation) was
not valid to estimate V
˙
O
2
in CAD patients. A modified predic-
tion equation of V
˙
O
2
was given and would need a larger
number of patients to be generalized.
Key Words: Coronary arteriosclerosis; Rehabilitation.
© 2003 by the American Congress of Rehabilitation Medi-
cine and the American Academy of Physical Medicine and
Rehabilitation
P
HYSICAL EXERCISE IS WIDELY USED as a modality
of treatment in the rehabilitation of patients with coronary
artery diseases (CAD) and often improves patients’ work ca-
pacities.
1-6
Rehabilitation programs, based on exercise, have
been designed to improve exercise performance and reduce risk
factors.
1-6
Exercise conditioning can increase functional capac-
ity and diminish the dependence and disability experienced by
patients with CAD.
1,7,8
An individualized cardiac rehabilitation
program requires a preliminary assessment of aerobic capacity
to determine suitable work intensities.
1,2,7
To set training intensities, a conventional laboratory exercise
test that assesses maximal aerobic capacity, with oxygen con-
sumption and gas exchanges, is also recommended.
1,2,4,5
To
follow the program’s training effects and to adjust work inten-
sities during rehabilitation according to the patient’s progress,
one must be able to determine symptom-limited oxygen con-
sumption (V
˙
O
2
). However, laboratory assessments are costly
because they require expensive equipment and a trained med-
ical staff.
Timed walking tests are good alternatives to laboratory testing
because they are cheaper and more simple to use. Among them,
the 20-meter shuttle test (20MST) was frequently used in sports
medicine to assess cardiorespiratory fitness
9-12
and, more recently,
it has been used in pathologic populations to assess functional
capacity.
13-17
This test is progressive—subjects are required to
reach their maximal effort—and its reliability greatly improved
with those populations.
14-18
The 20MST is based on the energy
cost of running and can be used to predict maximal V
˙
O
2
(V
˙
O
2
max)
in healthy and asthmatic subjects
19-22
and peak VO
2
in chronic
heart failure patients.
14
However, the limitation of aerobic perfor-
mance is a consequence of physical deconditioning in patients
with CAD or chronic heart failure.
3,23,24
Their deconditioning is
shown by oxygen uptake values lower than those of healthy
subjects.
3,24
The current 20MST
10
is generally performed with
initial running speeds of 8km/h. With their limitation in aerobic
performance, patients with CAD often have speeds under 8km/h.
On the 20MST, it is necessary to determine a patient’s functional
capacity from his/her maximal speed to estimate V
˙
O
2
and to adjust
training intensities. The loss in aerobic capacity,
1,3
which is re-
sponsible for exercise intolerance,
1
could modify the metabolic
energy cost of walking and running and consequently make the
equation that predicts V
˙
O
2
wrong and unusable. The 20MST has
not yet been studied in patients with CAD. Its use as a tool to
assess fitness and functional capacity would enlarge its role in
testing and training protocols. The aim of the present study was to
assess the validity of the 20MST
10
in the estimation of V
˙
O
2
max
and maximal speed in CAD patients and thereafter to develop, if
necessary, modified equation that can better predict their V
˙
O
2
max
from functional capacity.
METHODS
Participants
A random sample of 17 men with CAD (mean age
standard deviation [SD], 519y) took part in the study 1 month
From the Faculte ´ des Sciences du Sport, Universite ´ de Picardie Jules Verne,
Amiens (Gayda, Choquet, Temfemo, Ahmaı ¨di); and Centre de Re ´adaptation Cardi-
aque, Ho ˆpital de Corbie, Corbie (Choquet), France.
No commercial party having a direct financial interest in the results of the research
supporting this article has or will confer a benefit on the authors or on any organi-
zation with which the authors are associated.
Reprint requests to Saı ¨d Ahmaı ¨di, PhD, Faculte ´ des Sciences du Sport, Universite ´
de Picardie Jules Verne, Alle ´e P. Grousset, 80025, Amiens, France, e-mail:
said.ahmaidi@ca.u-picardie.fr.
0003-9993/03/8407-7485$30.00/0
doi:10.1016/S0003-9993(03)00036-4
1012
Arch Phys Med Rehabil Vol 84, July 2003