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Acta Univ. Palacki. Olomuc., Gymn. 2013, vol. 43, no. 1 35
RELIABILITY OF V SIT-AND-REACH TEST
USED FOR FLEXIBILITY SELF-ASSESSMENT IN FEMALES
Roman Cuberek*, Iva Machová, Michaela Lipenská
Faculty of Physical Culture, Palacký University, Olomouc, Czech Republic
Submitted in February, 2013
BACKGROUND: The V sit-and-reach (VSR) test seems to be an appropriate instrument of self-assessment of ham-
string and low-back flexibility for its ease of execution and the need for only a small amount of materials, space, and
examination skill requirements. It is assumed that the specificity of self-assessment (in general) can be the cause of
other sources of measurement error.
OBJECTIVE: This study aimed to analyze reliability of VSR when used as an instrument of self-assessment of flex-
ibility in adolescent females.
METHODS: The sample comprised 43 students (female; age 21.2 ± 0.5 years) from Palacký University in Olomouc
(Czech Republic). T-test (p < .05) and Pearson correlation coefficient was used to assess systematic bias and to de-
termine intra-individual reliability of the flexibility test; the standard error of measurement (SEM) and Bland and
Altman’s 95% limits of agreement were used to assess absolute reliability of the flexibility test.
RESULTS: The average intra-individual difference of 1.14 cm (increasing test performance) was found to be statisti-
cal significant (t = –5,375; df = 42). It was observed that high intra-individual reliability (r = .98); the absolute reli-
ability (SEM) is equal to 0.139 cm.
CONCLUSIONS: This study provides evidence supporting the usage of VSR as a relevant instrument of self-assess-
ment of hamstring and low-back flexibility in adolescent females.
Keywords: Health-related fitness, measurement error, testing, university student.
ence, ease of use, professional discipline, or tradition,
rather than scientific evidence (Davis, Quinn, White-
man, Williams, & Young, 2008). The reason probably
comes from the fact that there is still no convincing
proof or conclusively provided evidence of which test
is the most appropriate to use to assess hamstring and
low-back flexibility (Ayala, Sainz de Baranda, de Ste
Croix, & Santonja, 2012; Baltaci, Un, Tunay, Besler,
& Gerçeker, 2002; Hui & Yuen, 2000; López-Miñarro,
de Baranda, & Rodríguez-García, 2009). Taking into
account this fact as well as tests’ weaknesses and ad-
vantages, the choice is mostly related to conditions and
situations in which the test is realized.
Although SR and its alternatives are frequently
used due to ease of use, understandable procedures,
and minimal skills requirements, they are usually un-
suitable for self-assessment because of low availability
of their material needs (e.g. “test box”). For the pur-
pose of self-assessment the V sit-and-reach test (VSR)
seems to be the most appropriate, because it requires
only an adhesive tape and a measurement tool.
Some sources of measurement errors can be expect-
ed while HRF tests are realized as self-assessment in
comparison when testing process is performed by an
experienced or specially trained examiner. Therefore, if
INTRODUCTION
The sit and reach test (SR – originally named Canadian
Trunk Forward Flexion Test) is a field test used to mea-
sure hamstring and low-back flexibility (Baumgartner
& Jackson, 1995; Wells & Dillon, 1952). It is believed
that maintaining a good level of flexibility in these ar-
eas is an important part of health related fitness (HRF)
(Martin, Jackson, Morrow, & Liemohn, 1998), because
it prevents risk of falling, gait limitations or postural de-
viations and the most acute or chronic musculoskeletal
injuries and lower back problems (ACSM, 2000). SR
or some of its variations (for example Unilateral seated
sit-and-reach test, Chair sit-and-reach test, Modified sit-
and-reach test, Back saver sit-and-reach test, Toe-touch test
and V sit-and-reach test) are commonly used in health
related physical fitness test batteries (for example EU-
ROFIT, FITNESSGRAM, President’s Challenge, Uni-
fittest (6–60) and so on). The choice of the test to be
employed is more often based on the examiner’s prefer-
* Address for correspondence: Roman Cuberek, Institute of
Active Lifestyle, Faculty of Physical Culture, Palacký Uni-
versity, tř. Míru 115, 771 11 Olomouc, Czech Republic.
E-mail: roman.cuberek@upol.cz
36 Acta Univ. Palacki. Olomuc., Gymn. 2013, vol. 43, no. 1
a validity of VSR (performed as self-assessment) is sug-
gested from the content validity of the classical VSR
(with an examiner) then some decrease of the validity
might be considered as a result of the influence of mea-
surement error related to the self-assessment process.
The purpose of the study was to examine reliability
of the V sit and reach test used for the self-assessment
of hamstring and low-back flexibility in females as one
of the components of health related fitness.
METHODS
Participants
Forty three female students (age 21.2 ± 0.5 year, BMI
22.61 ± 3.10 kg·m
–2
) from the Faculty of Education of
Palacký University in Olomouc volunteered to partici-
pate in this study, which is in accordance with recom-
mended number of a minimum of forty persons for reli-
ability studies (Atkinson & Nevill, 1998). All subjects
were informed about the purpose of the study and all
procedures in this study before the testing. No female
was obese, or a professional athlete and none had a
physical impairment.
The project in which this study was realized, was
approved by the Ethics Committee of the Faculty of
Physical Culture of Palacký University in Olomouc
(document number 65/2011). Participants could leave
the study at any time during the practical component.
All participants signed a statement of informed con-
sent. All data of the study was used only for the pur-
pose of the study.
Data procedure
Testing took place in the athletic sport hall in Olomouc,
Czech Republic. All participants performed an eight
minute warm up and static stretching routine once they
had received the test card with the procedure of modi-
fied VSR test and a scoring sheet. On the scoring sheet
was the place for measured results (in cm) and subjects
had to enter basic information such as date of birth
and their height and weight (for calculation of BMI in-
dex). Subjects were instructed to perform testing alone
without any additional information except that given
on the test card. All testing tools were free to be used
and available. Description and information about the
VSR test was identical with the original VSR modifi-
cation as presented on the internet – INDARES.com.
The test card has a verbal description, two pictures
with the starting and reaching position of VSR togeth-
er with the description of scoring the result. Subjects
were instructed to perform two trials with a rest of
10–15 minutes between.
The instructions on the test card (originally written
in Czech language) – the subject removes their shoes
and sits on the floor with the measuring line between
their legs, the soles of their feet are placed immediate-
ly behind the baseline, heels about 20 cm apart. The
thumbs are clasped so that hands are together, palms
facing down and placed on the measuring line. With
the legs held flat, the subject slowly reaches forward
as far as possible, keeping the fingers on the baseline
and feet flexed. Movement should be smooth and with-
out bouncing. Here, the subject stays for 2 s. The test
is done twice with a short break in between as stated
above.
Scoring: Zero point is at the level of feet. (We note
negative values towards our body and positive values
outward from our body.) The best trial is recorded in
centimeters.
Statistical analysis
A level of participants’ flexibility was assessed by basic
statistics (mean, median, standard deviation, 95% con-
fidence interval) and compared to population norms
implemented in INDARES.com software. After ho-
moscedasticity (using the Pearson product-moment
correlation coefficient – the correlation between the
absolute differences of two repeated measurements and
the mean of two repeated measurements) and normal-
ity (Shapiro-Wilks W test, p < 0.05) were verified, two
tailed t-test of the repeated measurements (p < 0.05)
and Cohen’s effect size d were used to detect and as-
sess systematic bias. Subsequently the systematic bias
was considered as significant only in case when null hy-
pothesis (neither difference between repeated measure-
ments; t-test) was rejected and at the same large effect
size (classification according to Cohen (1988)) was
detected by Cohen’s d. The Pearson product-moment
correlation coefficient (test – re-test) as parameter of
intra-individual reliability was determined to assess the
intra-individual reliability. The standard error of mea-
surement (SEM) and Bland and Altman’s 95% limits
of agreement for two repeated measurements were
used to express and assess the reliability in the original
measurement unit, e.g. absolute reliability (Atkinson &
Nevill, 1998). To calculate the SEM, the following for-
mula was used (Thomas, Nelson, & Silverman, 2005):
SEM = SD·√(1-r), where SD is the standard deviation
of the intra-individual differences and r is the deter-
mined correlation coefficient. The statistical software
package SPSS 17.0 (SPSS Inc., Chicago, IL) was used
to compute all of the statistical characteristics.
RESULTS
The data of the first and the second measurement are
normal according to the normality of Shapiro-Wilkins
W test, p < .05 (W = 0.961, p = .150 for first, and
W = 0.995, p = .038 for second measurement). The low
value of Pearson product-moment correlation coeffi-
cient (r = -.135) shows at the homoscedasticity of data
Acta Univ. Palacki. Olomuc., Gymn. 2013, vol. 43, no. 1 37
and this signifies no risk of increased measurement er-
ror along with increasing test results.
The flexibility performances of female students are
listed in Table 1 together with the basic statistical dif-
ferences describing repetition of the test (intra-individ-
ual variability of performance).
It was found, that a difference -1.14 cm between the
first and the second measurement (shows an increase
of performance) is statistically significant on p < 0.05
(t = -5.375; df = 42). This is in contradiction to the
low effect size (Cohen, 1988) found by d = 0.16. High
value of Pearson product-moment correlation coeffi-
cient (r = .980) suggests a high level of intra-individual
reliability. Estimated standard error of measurement
(SEM) is 0.139 cm, where for two repeated measure-
ments are Bland and Altman’s 95% limits of agreement
among -1.3 cm to 4.1 cm. The SEM represents only
7.19 % of the unit of measurement in the test which can
be considered as practically insignificant.
DISCUSSION
Reliability is a theoretical concept used for a descrip-
tion of the quality of the measuring instruments and
procedures. Researchers and practitioners need to
know the level of reliability (as same as validity) to
justify their choice of an adequate measurement proce-
dure employed in data collection during specific activi-
ties. Knowledge of different sources of errors and level
of their influence help researchers and practitioners to
better understand, to interpret and to study particular
phenomenon.
The purpose of this study was to evaluate errors of
the field test (V sit-and-reach), which was realized as
a self-assessment test. This meant that an individual
was the examiner and subject, as the subjects had to
measure and record on their own. Logically, this pro-
cess can cause increasing influence of various sources
of measurement error. During the self-assessment,
the typical sources of measurement error can be the
process of learning. It can be understood as a process
to learn the move (that particular practical task) or to
learn how to operate the test. This can cause an in-
crease of the test performance. The next natural source
of measurement error is a sequence of tenses of tasks
during the test. There can be some moment during
testing when the subject (and examiner in one) cannot
process all necessary tasks at the same time even as
is required by the test itself. This results in a latency
of subtasks and overall increase of the test duration.
This disturbing effect is more important in those tests
where the score is related to the time (time as a result
or served as an interval of the test duration). Another
source of measurement error is an effect of a wrong
score reading from the measurement tool, which is
used during the testing. Mostly this is determined by
conflict between the final position of the subject and
the location of a measurement tool (set by the test
procedure) which enables the subject to read the test
score properly. The true score can be also influenced
by a subjective attitude of the subject to the recorded
result – subject intentionally shifts the score into his/
her performance-benefits (rounds off the score into the
performance-positive values or simply shifts the score).
A partial source of measurement error can be caused
by an experience with a process of testing. Some previ-
ous experience with testing (in general) of individual
can lead to a form of anticipation which reduces poten-
tial of measurement error.
The sample character allow us to consider our re-
sults as representative for a population of non-obese fe-
males in age of 20–30 years with good or good-to-mod-
erate level of flexibility of lower back and hamstrings
who have a normal amount of daily physical activities.
The findings based on participants’ test perfor-
mances in a range of 0–20 cm show that the magnitude
of measurement error in VSR does not depend on the
magnitude of measured value. This indicates that the
final subject’s position in the test should not influence
the reading of the values (reaching position) and there-
fore it does not have to be considered as a source of
measurement error. Although our results do not indi-
cate this influence, it can be recommended to eliminate
potential influence by the flat rectangular object (i.e.
a book) which is moved forward by the subject during
the forward bending.
Table 1
Females’ performance in the test V sit-and-reach (N = 43; the values are presented in cm)
Characteristics M 95% CI Mdn SD
The first measurement 10.1 (8.0, 12.2) 12 6.91
The second measurement 11.3 (9.1, 13.4) 13 7.10
Intra-individual differences*
-1.14 (-1.6, -0.7)
1 1.39
Note. CI = confidence interval, Mdn = median.
* the values are computed as X
1
-X
2
, where X
1
is the first and X
2
is the second measurement (testing
process).
38 Acta Univ. Palacki. Olomuc., Gymn. 2013, vol. 43, no. 1
It was found that during repeated measure-
ment the test performance increased in average by
1.14 ± 1.39 cm. This observed difference was recog-
nized as a statistically significant, but interpretation of
value of effect size (low effect) is not in agreement with
this finding. Based on the requirement of the confor-
mity of statistical significance and the effect size (see
methods) we have to classify observed test – re-test dif-
ference as insignificant. This conclusion corresponds
to high level of observed intra-individual reliability (an
interpretation of the value of the test – re-test correla-
tion) and also it identified indicators of absolute reli-
ability (the SEM and the Bland and Altman’s 95% lim-
its of agreement). Both, high level of absolute relative
reliability do not presuppose the existence of signifi-
cant sources of measurement error. These findings in-
dicate low probability of sources of measurement error
which originate from the self-assessment process. This
means that all changes in modification of VSR for self-
assessment are not (do not include) significant sources
of measurement error. This means that modified VSR
can be considered as an eligible instrument to measure
a reach distance in sitting position while performed by
an individual, even better when VSR is used for the pur-
pose of self-assessment of physical fitness. Regarding,
self-assessment of physical fitness it is more important
to carry out individual assessment than the outcome
achieved in the test. This can be an indication that the
individual is aware of the need for change and it can be
considered as a first step leading to an active life style.
It must be kept in mind that this study was carried
on under the specific conditions and their change(s)
can result in different findings. (Especially) For exam-
ple, the implementation and realization of the warm-
up before the test can be considered (generally) as a
significant sources of measurement error. This simple
fact of warming or previous stretching of muscle fibers
can result increased flexibility in particular joints. This
effect of warm-up on the level of performance in flex-
ibility tests, in our case of hamstring and low-back flex-
ibility tests, was verified by numerous studies (Arazi,
Asadi, & Hoseini, 2012; Golden, Hoffman, Pavol, &
Wallace, 2005; O’Sullivan, Murray, & Sainsbury, 2009;
Zakaz, Grammatikopoulou, Zakas, Zahariadis, & Vam-
vakoudis, 2006). This influence of a warm-up on reli-
ability of VSR should be studied more and it’s correc-
tion of realization of the form of warm-up can lead to
higher standardization of VSR or similar tests.
CONCLUSIONS
This study provides the evidence of a high level of re-
liability, resp. appropriate reliability, of the V sit-and-
reach test used as an instrument of the self-assessment
of hamstrings and low-back flexibility in adolescent fe-
males. According to these findings it is not important
to consider the double role of an examiner as well as
a subject in the test as a source of measurement error.
ACKNOWLEDGMENTS
The authors of this study would like to thank the stu-
dents for their participation in the study. The study has
been supported by the student’s research grant from
the Palacký University (IGA No. FTK_2012:021)
“Self-assessment of health-related fitness: Reliability
assessment of four fitness tests”.
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RELIABILITA V SIT-AND-REACH TESTU VYUŽI-
TÉHO K SEBEHODNOCENÍ FLEXIBILITY U ŽEN
(Souhrn anglického textu)
ÚVOD: Ukazuje se, že V sit-and-reach test (VSR) je
vhodným nástrojem k sebehodnocení flexibility ham-
stringů a oblasti bederní páteře. Důvodem je přede-
vším fakt, že test je poměrně snadno proveditelný, je
nenáročný na materiální vybavení a nevyžaduje příliš
znalostí a zkušeností z oblasti užívání motorických tes-
tů. Vzhledem ke specifikům formy realizace testu, tj.
při sebehodnocení, lze u tohoto testu očekávat existen-
ci několika zdrojů chyb měření. Důsledkem může být
snížení reliability testu.
CÍL: Záměrem studie je posoudit reliabilitu VSR při
jeho použití formou sebehodnocení při posuzování fle-
xibility u adolescentů (ženy).
METODY: Výzkumný soubor tvořilo 43 studentek
(věk 21,2 ± 0,5 let) Univerzity Palackého v Olomouci.
Ke stanovení systematické chyby a vymezení intra-in-
dividuální reliability testu byl použit t-test pro opako-
vaná měření (p < 0,05), resp. Pearsonův korelační ko-
eficient. K posouzení absolutní reliability byly použity
směrodatná chyba měření (SEM) a Bland-Altmanovy
95% limity shody.
VÝSLEDKY: Průměrný intra-individuální rozdíl mezi
opakovanými měřeními (1,14 cm) byl shledán jako sta-
tisticky významný (t = –5,375; df = 42). Intra-individu-
ální reliabilita byla klasifikována jako vysoká (r = 0,98);
absolutní reliabilita odpovídá hodnotě 0,139 cm.
ZÁVĚRY: Studie poskytuje důkazy, že VSR je vhod-
ným nástrojem při sebehodnocení flexibility hamstrin-
gů a oblasti bederní páteře u adolescentních dívek.
Klíčová slova: zdravotně orientovaná zdatnost, chyba mě-
ření, testování, vysokoškolský student.
