Introduction
Sickle cell anemia (SCA) is the most common monogenic disease in the
world, predominant among people of African descent and brown skin. It is
characterized by the occurrence of sickle cells due to the mutant
presence of hemoglobin S (HbS).1 The altered
erythrocytes present difficulty in circulating in the blood, which
causes vaso-occlusive phenomena and infarction in the affected area. In
addition, this altered physiology causes permanent damage to tissues and
organs, with the cardiorespiratory system being the target of acute and
chronic manifestations.2 Thus, lung function and
cardiovascular impairments changes favor a sedentary lifestyle, reduced
functional capacity and worsening quality of life
(QOL).3,5,6 Different tests that assess functional
capacity are available. Hostyn4 et al. (2013), showed
higher number of hospitalizations in children and adolescents with SCA
(genotype Hb-Sβ0–thalassemia) who walked shorten
distance at the 6-minute walk test (6MWT). This test has been widely
used, however there are some limitations as self-paced test, floor
effect. Thus, the Modified Shuttle Walk Test (MSWT) in patients with SCA
can be an alternative, considering it has already been described in
children and adolescents’ other chronic conditions.7
-10
The MST is simple and low cost, needs corridor of 10 meters (m), limited
by symptoms, externally paced, and allows the volunteer walk or
run.4 This test is appropriated to assess exercise
intolerance in individuals with different severity status. Additionally,
the MSWT can be used to exercise prescription. 11 The
sit and stand movement are considered fundamental for mobility and
functional independence. This movement is part of several activities of
daily living (ADL) and the literature has already described the
5-repetition sit-to-stand test (5STS-test) as a simple and low coast
test to measure lower limb strength, balance control, risk of falling
and exercise capacity.13 Thus, the 5STS-test is
another alternative to assess different aspects of functional capacity
compared to MSWT. This study aims to evaluate and compare the functional
capacity, pulmonary function and quality of life of children and
adolescents with SCA with their healthy peers and to analyze the
reproducibility of the functional capacity tests on the sickle cell
anemia group. The hypotheses are that SCA individuals have reduced
exercise capacity, lung function and quality of life.