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evaluations based on tests that involve different mus-
cle groups (13–15). The muscle function test (MFT)
enables assessment of the muscle endurance of both
the lower and the upper limbs (12).
Finally, functional capacity was defined as patients’
ability to perform activities of daily living at their own
pace (16). Functional capacity is often measured sub-
jectively with the Duke Activity Status Index (DASI),
a self-administered questionnaire (17). The DASI
enables brief assessment of the functional capacity
of selected aspects of daily living that can influence
quality of life in cardiovascular patients (18).
Since physical fitness is multidimensional, it is
difficult to assess, especially in patients with HF (14,
19). Both objective (e.g. 6MWT) and subjective (e.g.
DASI) methods can be used. This measurement can
become even more challenging in patients with HF
who have movement impairment, e.g. due to stroke
or claudication. Although exercise capacity, muscle
function and functional capacity may represent dif-
ferent, but related, aspects of the multidimensionality
of physical fitness in patients with HF, few studies
have analysed these relationships. In most instances,
only 2 of these 3 aspects have been evaluated (14, 20).
Borland et al. reported a moderate positive correlation
between exercise capacity and muscle function (14),
and Myers et al. reported a moderate positive correla-
tion between exercise capacity and functional capacity
(20); however, no evidence regarding the relationship
between muscle function and functional capacity
was described. Therefore, the aims of this study were
2-fold: first, to describe the relationships among 3
measures of physical fitness (exercise capacity, muscle
function, and functional capacity) in patients with HF;
and, secondly, to determine whether these measures
are affected by impairment of movement.
The research questions addressed by this study were:
• Are there relationships among exercise capacity,
muscle function, and functional capacity in patients
with HF?
• Are there relationships among the 3 measures of phy-
sical fitness and demographic and clinical data, such
as age, sex, New York Heart Association (NYHA)
classification, and ejection fraction (EF)?
• Is there a relationship between physical fitness and
movement impairment in patients with HF?
METHODS
Participants and setting
This study used the data collected for Italian patients who par-
ticipated in the HF-Wii study (21), an international randomized
controlled trial that aimed to improve exercise capacity in pa-
tients with HF through the use of exergaming (clinicaltrial.gov
www.medicaljournals.se/jrm
identifier: NCT01785121). Patients were enrolled in the Villa
delle Querce Hospital in Nemi (Rome, Italy) from October 2014
to December 2016. The eligibility criteria were specified in the
original study protocol (21). Briefly, the HF-Wii study enrolled
adult patients with HF, who were able to use exergames (without
limiting visual, hearing, motor or cognitive impairments) and
with a life expectancy of more than 6 months (21). Regarding
movement impairment, only those patients who were not able
to swing their arms at least 10 times in a row were excluded. In
addition to the data from the HF-Wii protocol, additional data
on functional capacity were collected.
Ethical considerations
This study was conducted in accordance with the principles
of the Declaration of Helsinki (2008 version) and the Medical
Research Involving Human Patients Act of Italy, the country
involved in this multicentre study. Ethical approval (n. 101.14
prot. N. 47867 of 02.07.2014) was obtained in Italy . All of the
patients were fully informed about the study goals. They were
also reassured about the confidentiality of their data, and provi-
ded signed informed consent before the start of data collection.
Measures
A battery of measures was used in the HF-Wii study, but, for the
purpose of this study, only the following have been included:
exercise capacity, muscle function, functional capacity, and
demographic and clinical data.
Exercise capacity
Exercise capacity was assessed with the 6MWT. The distance
(m) walked in 6 min on a flat, firm surface on a linear track
marked with visible signs represents the 6MWT score (10). It is a
frequently used, reliable and well-validated measure of exercise
capacity for patients with HF (22). The 6MWT has been also
recommended for monitoring the course of the disease and the
evaluation of the effects of interventions in these patients (23).
Some studies have reported a correlation between the 6WMT
and peak of oxygen consumption (r = 0.490–0.790) (20, 24)
and EF (r = 0.280) (20). A distance ≥ 300 m walked during the
6MWT has been shown to have a prognostic value for patients
with HF. Patients who walked ≥ 300 m had a lower event-free
survival at 36 months than patients who walked less than 300
m (25). Considering its objectivity and lower cost, the 6MWT
represents a valid method for assessing exercise capacity (3).
Muscle function test
The muscle function isotonic test (MFT), which simulates the
muscle function normally required for activities of daily living,
was used. The MFT is composed of 3 evaluations, which pro-
vide 3 different scores: the unilateral isotonic heel-lift, bilateral
isometric shoulder abduction, and unilateral isotonic shoulder
flexion (12). The MFT has also been used for patients with
other cardiac diseases, such as coronary artery and congenital
heart diseases (26, 27). Age and NYHA functional class are the
main predictors of MFT scores in patients with congenital heart
disease (27); however, no correlations have been found between
MFT scores and EF in patients with HF (28).
The unilateral isotonic heel-lift was performed by having
the patient touch the wall with the fingertips while their arms
were elevated to shoulder height for balance. The patients had
to perform a maximal heel-lift on a 10° tilted wedge: one lift