Time-of-day effect on hip flexibility associated with the modified sit-and-reach test in males

Abstract

Flexibility is a key component of physical fitness. It has been suggested that measures of physical fitness components may vary throughout the day. The aim of this study was to analyze the effects of the time of day on flexibility performance. Twenty-six men (mean age = 25.4 years, SD = 2.5) were evaluated by hip flexion on kinematic analysis and also by an absolute score in the modified Sit-and-Reach test during a repeated measure design. This was done during three experimental sessions, which occurred at 8:00AM, 1:00PM, and 6:00PM, in random order. All subjects were previously familiarized with the test parameters. There was a diurnal variation only in the modified Sit-and-Reach test score between 8:00AM and 6:00PM (P = 0.01). There was no significant difference in the hip kinematic analysis between hours. These findings suggest that flexibility performance in the modified Sit-and-Reach test, in absolute scores, is affected by the time of day, with higher performance in the evening.

Full text

Page 1

947
Orthopedics & Biomechanics
Guariglia DA et al. Time of Day Eff ect … Int J Sports Med 2011; 32: 947–952
accepted after revision
May 31 , 2011
Bibliography
DOI http://dx.doi.org/
10.1055/s-0031-1283182
Published online:
November 3, 2011
Int J Sports Med 2011; 32:
947–952 © Georg Thieme
Verlag KG Stuttgart · New York
ISSN 0172-4622
Correspondence
Prof. Jeff erson Rosa Cardoso,
PT, PhD
Universidade Estadual de
Londrina
Physical Therapy
Av. Robert Kock 60
Londrina
Brazil
86038-350
Tel.: +55/43/3371 2649
Fax: +55/43/3371 2459
jeff car@uel.br
Key words
● ▶ range of motion
● ▶ circadian rhythm
● ▶ performance
Time-of-Day Eff ect on Hip Flexibility Associated with
the Modifi ed Sit-and-Reach Test in Males
sible interference from environmental factors,
whether emotional or physical.
There are several ways to measure the hamstring
fl exibility. Sit-and-Reach test (SRT) is one way to
assess it [ 7 ] . Although this test is widely used in
many fi tness batteries, it is believed that certain
factors could alter its results as: disproportion
between the upper and lower limbs relative to the
trunk and scapular abduction [ 14 , 15 ] . Another
important factor is that the test does not distin-
guish the contributions of the lower back or ham-
string muscles during the test. Due to these
problems, several authors have explored diff erent
ways to modify this test [ 3 , 14 , 16 , 18 ] . The SRT
measured by the angle of the hip joint (AHJ) was
shown to be reliable [ 5 ] . However, it showed the
infl uence of the gastrocnemius muscles on the
results of this measure [ 17 ] . Based on these
premises, the purpose of this study was to analyse
the eff ects of time of day on fl exibility performance
in young adult males using SRT and AHJ and to also
evaluate intra- and inter-observer reliability.
Method
▼
Subjects
26 young adult men ( ● ▶ Table 1 ) were selected to
participate voluntarily in this study, using the
Introduction
▼
Flexibility is a key component of physical fi tness,
health, and athletic performance [ 23 ] . Changes in
fl exibility can be attributed to diff erent factors
such as growth, physical development, aging,
body temperature, training or even detraining
[ 6 , 11 , 36 ] . It has been suggested that measures of
physical fi tness components may vary through-
out the day [ 4 , 31 ] , possibly due to fl uctuations
caused by hormonal changes, body temperature,
speed, and perception of fatigue, amongst other
factors [ 9 , 12 , 19 , 25 , 26 , 28 , 33 ] . Some studies
have reported the impact of diurnal variation on
performance fl exibility, however, more informa-
tion is needed [ 2 , 20 , 26 , 35 ] .
The assessment of fl exibility has been used as an
important resource for the selection of athletes,
the prescription of interventions and the analysis
of their eff ectiveness. This is also considered a
diagnostic aspect of physical fi tness [ 11 , 24 , 27 ] .
Thus, the search for more consistent and precise
measures of this variable is a high priority. It is
worth mentioning that the quality of fl exibility
performance measures can aff ect both the diag-
nosis and the analysis of intervention strategy
eff ectiveness. Rigorous methodological control
measures, therefore, can reduce or eliminate pos-
Authors D. A. Guariglia 1 , L. M. Pereira 1 , J. M. Dias 1 , H. M. Pereira 2 , M. O. Menacho 3 , D. A. Silva 1 , E. S. Cyrino 4 ,
J. R. Cardoso 1 , 4
Affi liations Affi liation addresses are listed at the end of the article
Abstract
▼
Flexibility is a key component of physical fi tness.
It has been suggested that measures of physical
fi tness components may vary throughout the
day. The aim of this study was to analyse the
eff ects of the time of day on fl exibility perform-
ance. 26 men (mean age = 25.4 years, SD = 2.5)
were evaluated by hip fl exion on kinematic anal-
ysis and also by an absolute score in the modifi ed
Sit-and-Reach test during a repeated measure
design. This was done during 3 experimental
sessions, which took place at 8:00 a.m., 1:00 p.m.
and 6:00 p.m., in random order. All subjects were
previously familiarized with the test parameters.
There was a diurnal variation only in the modi-
fi ed Sit-and-Reach test score between 8:00 a.m
and 6:00 p.m. ( P = 0.01). There was no signifi cant
diff erence in the hip kinematic analysis between
hours. These fi ndings suggest that fl exibility per-
formance in the modifi ed Sit-and-Reach test, in
absolute scores, is aff ected by the time of day,
with higher performance in the evening.
Downloaded by: Lenamar Vieira. Copyrighted material.

Page 2

948
Orthopedics & Biomechanics
Guariglia DA et al. Time of Day Eff ect … Int J Sports Med 2011; 32: 947–952
following inclusion criteria: not having practiced regular physi-
cal activity (frequency greater than once a week) in the 6 months
prior to the experiment, having suff ered no sleep disturbances
or not having travelled on a trans-meridian fl ight in the same (6
month) period. Individuals who had back pain, history of lower
extremity injury or surgery were excluded. All subjects provided
written, informed consent with a form approved by the Human
Research Ethics Committee of the Universidade Estadual de
Londrina (107/08). This study followed the ethical recommen-
dations of the journal [ 13 ] .
Experimental procedure
The samples were collected during daylight saving time, between
the months of November and January. All assessments took
place in a laboratory under controlled temperature conditions
(between 22 and 26 °C). Participants were instructed not to
modify their normal routines and to avoid both strenuous phys-
ical activity and the consumption of alcohol or stimulants, such
as caff eine, in the 24 h prior to the test sessions.
All volunteers had 5 visits to the laboratory on diff erent days,
with a minimum of 29 h between visits. The fi rst visit included
anthropometric measures, familiarization with the tests, signing
the consent form and individualized guidance about the proce-
dures and routines to be followed. In the 3 subsequent visits,
fl exibility tests were performed according to established guide-
lines, but in randomized schedules among the subjects between
the times (8:00 a.m., 1:00 p.m., 6:00 p.m.), for example, there
were 6 sequence possibility schedules for each individual for the
3 subsequent visits presented in the ● ▶ Fig. 1 . For reliability, an
evaluation was conducted with one more test on the last visit, at
one of 3 set hours.
Test protocol
Flexibility performance was evaluated using kinematic hip anal-
ysis. To perform this procedure, a wooden box (adapted from
Wells) 30.5 cm × 30.5 cm × 30.5 cm, with a fi xed 23 cm ruler on
top, was used in the study [ 34 ] . A little door measuring 27 cm x
27 cm was built into the front so that the subjects could place
their feet inside the box. For the Sit-and-Reach test (SRT), this
door was open, permitting assessment of the infl uence of the
gastrocnemius [ 17 ] ( ● ▶ Fig. 2 ).
A digital camera was positioned on a tripod at a height of 72 cm
and 202 cm away from the subject. A photo was taken at the
point of maximum performance in the SRT, i. e., with hands
crossed, as the subject slid the hands as far forward as possible
while the trunk faced towards the box [ 34 ] . This procedure was
performed 3 times in each session and the best result was con-
sidered for the analysis.
Additionally, the subject was told the value of the SRT (furthest
distance from the seat), in accordance with the procedures and
standards described in the literature [ 1 ] . Individuals were not
allowed any warm-up or stretching prior to testing.
The fi nal position that the subjects reached in the SRT did not
take the hip joint angle (HJA) into account. The length of the
hamstring muscle can be measured by the inclination angle of
the sacrum and pelvis in relation to the horizontal line at the
point of maximal forward reach on the SRT. This represents an
indirect measure of the HJA. Furthermore, when the HJA is
assessed during the SRT, diff erences in the length of upper and
lower limbs and the contribution of low back can be eliminated
[ 5 ] . The HJA can be assessed by angular kinematic analysis with
a high reliability [ 5 ] .
The hip joint angle was calculated using the angle formed by the
refl ective markers that had been placed on 2 anatomical land-
marks, namely the greater trochanter and anterior superior iliac
spine. During the fi rst data collection, after placing the markers
on the subject’s body, the spots were coloured with henna so
that on subsequent visits the marker could be placed on the
same exact site again. The angle formed by the inclination of the
sacrum and pelvis ( ● ▶ Fig. 1 ) was determined with AutoCAD
(2004) software [ 5 , 17 ] . The AutoCAD analysis was performed by
a single evaluator. To check the reliability of the adopted testing
program, Evaluator 1 analysed the photo of each subject twice,
while Evaluator 2, who had no access to the results of Evaluator
1, also performed this same procedure.
Statistical analysis
The variables were tested for normal distribution with the Sha-
piro-Wilk test and then presented as mean and standard devia-
tion. To identify the diff erences in fl exibility performance at
diff erent times of day, the analysis of variance (ANOVA) for
repeated measures was used, which met the assumptions of
Table 1 Anthropometric characteristics.
Anthropometric characteristics (n = 26) Mean (SD)
age (years)
body mass (kg)
height (m)
BMI (kg/m 2 )
25.4 (2.5)
80.3 (14.6)
1.77 (0.06)
25.3 (4)
BMI = body mass index
Fig. 1 Schedules sequence possibility for the measures.
First day measure
Second day measure
Third day measure
08:00AM
08:00AM
01:00PM
01:00PM
06:00PM
06:00PM
01:00PM
06:00PM
08:00AM
06:00PM
08:00AM
01:00PM
06:00PM
01:00PM
06:00PM
08:00AM
01:00PM
08:00AM
1
2
3
4
5
6
Fig. 2 Illustration of the adapted Wells bench with door open and the
measure of the hip joint angle.
Downloaded by: Lenamar Vieira. Copyrighted material.

Page 3

949
Orthopedics & Biomechanics
Guariglia DA et al. Time of Day Eff ect … Int J Sports Med 2011; 32: 947–952
sphericity. When the F value was signifi cant, the Bonferroni post
hoc test was used to identify the diff erences. Additionally, we
calculated the eff ect size among the times of day by the calcula-
tion proposed by Reilly [ 25 ] for this kind of study: (average of
time 1 – average time 2)/[(standard deviation 1+ times the stand-
ard deviation of schedule 2)/2].
Further analysis of the modifi ed SRT, with and without hip joint
angle, was performed with the Pearson product-moment corre-
lation coeffi cient. To check the reliability of intra- and inter-
observer results, the intra-class correlation coeffi cient (ICC),
1-way random eff ect analysis of the variance model, was used,
as well as the agreement analysis of Bland and Altman [ 7 , 30 ] .
The statistical signifi cance adopted for all tests was 5 %. The Sta-
tistical Package for Social Sciences (SPSS) version 15.0 and Med-
Calc 10.0.1.0. were used for statistical analysis.
Results
▼
● ▶ Table 2 and ● ▶ Fig. 3 , 4 present information on intra- and
inter-observer reliability according to hip joint angle (HJA). The
results indicated high reliability (ICC = 1.0) and a good agree-
ment between the intra- and inter-observer results (limits of
agreement of less than 1).
According to the absolute scores and hip joint angle, ● ▶ Table 3
and ● ▶ Fig. 5 present information on the reliability of the meas-
urements in the SRT at the same time of day. The results indicate
that the measurements recorded in this test are highly repro-
ducible (ICC = 0.9 and 0.98, respectively) and present a good
agreement – according to score analysis of both the absolute
measure and the HJA (the diff erence between the average close
to zero with low limits of agreement).
Performance tests of fl exibility
● ▶ Table 4 presents the SRT data at 3 diff erent times of day. A
signifi cant time-of-day eff ect ( P = 0.01) was observed only for
the absolute scores, with the post hoc test indicating signifi cant
improvement in performance (~7 %) in the evening (6:00 p.m.)
relative to the morning (8:00 a.m.). Nevertheless, a signifi cant
time-of-day eff ect was not confi rmed ( P = 0.48) in HJA, even
though there was a measurable increase between 8:00 a.m. and
6:00 p.m. (~2 %). The Pearson correlation analysis between the
measurements in the SRT (absolute score and hip joint angle)
showed a moderate correlation ( r = 0.57) and a R 2 = 0.32. ● ▶ Table 5
presents the eff ect size in the fl exibility measures at 3 diff erent
times of day. The largest eff ect was found on SRT between
8:00 a.m. and 6:00 p.m.
Discussion
▼
The study was designed to eliminate the infl uence of variables
that might have compromised the quality of the results. The
sample was composed of young males who did not engage in
physical activity more than once a week since the majority of
investigations into the eff ects of chronobiology on human per-
formance have been conducted with athletes and the physically
Table 2 Intra- and interobserver reliability results (n = 26).
ICC (1-way
random)
Bland and Altman

intra-observer 1 1.0 (1.00;1.00)
intra-observer 2 1.0 (0.99;1.00)
interobserver
ICC = intraclass correlation coeffi cient; 95 % IC = 95 % confi dence interval; d̄ = mean
diff erence; SE of d̄ = standard error of the mean diff erence;
95 % CI for d̄ = confi dence interval for the mean diff erence
ICC (95 % CI) d̄ SE of d̄
0.52
0.65
0.59
95 % CI for d̄
[− 0.17;0.25]
[− 0.14;0.37]
[− 0.28;0.20]
0.04
0.12
− 0.04 1.0 (1.00;1.00)
Fig. 3 Bland Altman Plot of intra-observer 1 and 2 reliability results (n = 26).
1.5
1.0
+1.96 SD
+1.96 SD
–1.96 SD
–1,16
–1.96 SD
–1,00
1,07
2.0
1.5
1.0
0.0
–0.5
–1.0
–1.5
0.5
1,39
0,12
Mean
0,04
Mean
0.5
0.0
–0.5
–1.0
–1.5
observer 1, test 1 – observer 1, test 2
observer 2, test 1 – observer 2, test 2
AVERAGE of observer 1, test 1 and observer 1, test 2 AVERAGE of observer 2, test 1 and observer 2, test 2
40 6080100 120
140
4060
80
100120140
Fig. 4 Bland Altman Plot of HJA inter-observer reliability results (n = 26).
406080 100120140
–1.5
–1.0
–0.5
0.0
0.5
1.0
1.5
AVERAGE of observer 1 and observer 2
observer 1 – observer 2
Mean
0,04
–1.96 SD
–1,14
+1.96 SD
1,21
Downloaded by: Lenamar Vieira. Copyrighted material.

Page 4

950
Orthopedics & Biomechanics
Guariglia DA et al. Time of Day Eff ect … Int J Sports Med 2011; 32: 947–952
fi t [ 4 , 19 , 20 , 22 ] . Generalizations based on results from a sample
of athletes may not be reliable since their circadian rhythms may
have been altered by adaptations to a fi xed training schedule
[ 32 ] .
A second characteristic of the study was to establish a random
order of testing during the day, in order to eliminate the bias of
learning by repetition. Studies, mainly with sedentary adults,
involving the execution of motor tests on diff erent days have
confi rmed this hypothesis [ 14 , 15 ] .
Studies in the literature have investigated possible variations in
fl exibility due to time of day. Their samples were diverse, con-
sisting of athletes [ 26 ] , low back pain patients [ 10 ] and healthy
subjects [ 12 ] which make the comparison diffi cult. However,
regardless of the sample characteristics, observing each of the
studies verifi es that it is not the characteristic of the sample that
defi nes whether or not there are fl exibility changes throughout
the day. It can be hypothesized that perhaps the outcome diff ers
depending on the joint, movement or the instrument of meas-
ures adopted, but more research is needed to confi rm this
hypothesis.
The results of this study indicated improved fl exibility in SRT
scores in absolute terms throughout the day, especially at night,
but this result was not found with the HJA. The other studies
that examined the time-of-day eff ect on fl exibility, despite using
other measurement methods, also found increased fl exibility
values at night compared to morning in some fl exibility tests to
measure lumbar fl exion as modifi ed-modifi ed Schober test [ 20 ] ,
electronic inclinometer [ 2 ] , inclinometer [ 10 ] and stereophotog-
raphy [ 35 ] , additionally the hamstring fl exibility evaluated by
the active knee extension test [ 20 ] to assess diff erent popula-
tions. Previous studies have shown that the performance of
some activities is usually best in the late afternoon or early
evening, near the peak of the circadian rhythm for body tem-
perature (acrophase) [ 19 , 31 ] . Thus, one possible explanation for
our results seems to be that there is an increase in body tem-
perature towards the evening, a phenomenon described in other
studies on the impact of chronobiology on physical performance
[ 26 , 31 ] . Therefore, although the possible mechanisms are still
unknown, an increase in body temperature can lead to, among
other important changes, reductions in the rigidity of connec-
tive tissue and in muscle viscosity [ 29 ] .
More recently, Onambele-Pearson and Pearson [ 21 ] , despite not
having been the main focus of the study, demonstrated that the
time of day was related to tendon stiff ness changes and with the
muscle fascicle length changes. Therefore, we proposed that ten-
don stiff ness is decreased in the evening.
Some comments are necessary regarding the HJA results. It was
expected that the test results would be diff erent. The R 2 was
0.32, in other words, only 32 % of the result can be explained by
the relationship of the tests, 68 % is due to other variables.
Although they measure the same variable, these tests assess dif-
ferent items, and thus it was determined that not all segments of
fl exibility present variations throughout the day, as mentioned
in a previous study on low back pain [ 10 ] .
The SRT was developed to analyse the hamstring fl exibility [ 34 ] ,
but while the SRT may have been developed for this objective,
multiple studies have shown that it is a poor measure of ham-
string muscle length and presents limitation and confounding
factor [ 7 ] as trunk and extremity length variability has the
potential to signifi cantly aff ect the SR test [ 14 , 15 ] . However, the
Table 4 Mean values (SD) of SRT for diff erent types of analysis at diff erent
times of day (n = 26).
8 h 13 h 18 h F P
SRT (cm)
SRT-HJA (º)
27.5 (6.9)*
81.0 (21.1)
28.6 (6.8)
82.1 (18.2)
29.3 (6.9)*
82.7 (18.9)
8.57
0.73
0.001
0.485
Table 5 SRT and hip kinematic eff ect size (n = 26).
8 h X 13 h 13 h X 18 h 8 h X 18 h
SRT
SRT-HJA
0.16
0.06
0.10
0.03
0.26
0.09
Table 3 SRT reliability results, according to absolute score and kinematic
analysis at the same time of day (n = 26).
ICC (1-way random) Bland and Altman
SE of d̄
1.67
6.71

SRT (cm)
SRT-HJA ( °)
ICC = intraclass correlation coeffi cient; 95 % IC = 95 % confi dence interval; d̄ = mean
diff erence; SE of d̄ = standard error of the mean diff erence; 95 % CI for d̄ = confi dence
interval for the mean diff erence
ICC (95 % CI)
0.98 (0.96:0.99)
0.97 (0.93;0.98)
d̄
0.0
− 0.7
95 % CI for d̄
[− 0.67;0.67]
[− 3.36;2.05]
Fig. 5 Bland Altman Plot of SRT and SRT-HJA reliability analysis at the same time of day results (n = 26).
4
+1.96 SD
+1.96 SD
–1.96 SD
–13,8
–1.96 SD
3,3
12,5
–3,3
Mean
0,0
Mean
–0,7
3
2
1
0
15
15
10
5
0
–5
–10
–15
–20
20
AVERAGE of SRT1 and SRT2 AVERAGE of SRT-HJA1 and SRT-HJA2
SRT1 – SRT2
25 30354040 6080100 120 140 45
–1
–2
–3
–4
Downloaded by: Lenamar Vieira. Copyrighted material.

Page 5

951
Orthopedics & Biomechanics
Guariglia DA et al. Time of Day Eff ect … Int J Sports Med 2011; 32: 947–952
Sit-and-Reach test was adopted because it is still a test widely
used in many fi tness batteries. Therefore, it was assumed that
for its implementation it was necessary to mobilize the gastroc-
nemius, the posterior thigh, the lower back and the arms, hands
and fi ngers, as well as perform scapula abduction and shoulder
extension.
To interpret the fi ndings of this study some limitations should
be considered. The fi rst factor to be considered is the absence of
women in the sample. This was done because the menstrual
cycle can aff ect the results. The disruptions in hormone balance
throughout the menstrual cycle have been implicated in physi-
cal performance, body temperature, metabolism and blood fl ow
[ 8 ] . Other important limitations are the small sample size which
allows for the possibility of a larger occurrence of the type II
error in the post hoc analysis, and the limited variability in the
age range. These factors can have an impact on the external
validity of the results, thus, the calculation of statistical power
between the hours provides an added help for the small sam-
ples. Another limitation was the lack of assessment of factors
such as: central and peripheral fatigue, emotional state, and
dietary intake.
The subjects in this study performed better in the evening than
in the morning, however, kinematic analysis revealed that the
measure of the trunk did not follow this variation. Probably, the
performance in the modifi ed SRT can be explained by other fac-
tors involved during the test which also need to be investigated
further.
Conclusion
▼
The results suggest that fl exibility performance in the SRT is
aff ected by time of day in terms of absolute scores in young adult
men who do not participate in regular activity, with the best per-
formance occurring in the evening, despite the lack of HJA change.
Acknowledgements
▼
The last 2 authors would like to thank the Conselho Nacional de
Desenvolvimento Cientifíco e Tecnológico (CNPq), a Brazilian
agency linked to the Ministry of Science and Technology, for the
Productivity Scholarship.
References
1 AAHPERD . Physical Best. Reston, VA, 1988. American Alliance for
Health, Physical Education, Recreation and Dance
2 Adams M A , Dolan P , Hutton W C . Diurnal variations in the stresses on
the lumbar spine . Spine 1987 ; 12 : 130 – 137
3 Baltaci G , Un N , Tunay V , Besler A , Gerçeker S . Comparison of three
diff erent sit and reach tests for measurement of hamstring fl exibility
in female university students . Br J Sports Med 2003 ; 37 : 59 – 61
4 Brisswalter J , Bieuzen F , Giacomoni M , Tricot V , Falgairette G . Morning-
to-evening diff erences in oxygen uptake kinetics in short-duration
cycling exercise . Chronobiol Int 2007 ; 24 : 495 – 506
5 Cardoso J R , Azevedo NC T , Cassano C S , Kawano M M , Ambar G . Intra- and
interobserver reliability of angular kinematic analysis of the hip joint
during the sit-and-reach test to measure the hamstrings length in
universitary students . Rev Bras Fisioter 2007 ; 11 : 133 – 138
6 Davis D L , Maia J A , Beunen G B , Lefevre J A , Claessens A L , Marques A T .
Skeletal maturation and physical fi tness in children and adolescents
in Madeira . Rev Port Cien Desp 2003 ; 3 : 61 – 78
7 Davis D S , Quinn R O , Whiteman C T , Williams J D , Young C R . Concurrent
validity of four clinical tests used to measure hamstring fl exibility . J
Strength Cond Res 2008 ; 22 : 583 – 588
8 Dawson E , Reilly T . Menstrual cycle, exercise and health . Biol Rhythm
Res 2009 ; 40 : 53 – 69
9 Drust B , Waterhouse J , Atkinson G , Edwards B , Reilly T . Circadian
rhythms in sports performance – an update . Chronobiol Int 2005 ; 22 :
21 – 44
10 Ensink F B , Saur P M , Frese K , Seeger D , Hildebrandt J . Lumbar range
motion: infl uence of time of the day and individual factors on meas-
urements . Spine 1996 ; 21 : 1339 – 1343
11 Fatouros I G , Kambas A , Katrabasas I , Leontsini D , Chatzinikolaou A ,
Jamurtas A Z , Douroudos I , Aggelousis N , Taxildaris K . Resistance train-
ing and detraining eff ects on fl exibility performance in the elderly are
intensity-dependent . J Strength Cond Res 2006 ; 20 : 634 – 642
12 Giff ord L F . Circadian variation in human fl exibility and grip strength .
The Aust J Physiother 1987 ; 33 : 3 – 9
13 Harriss DJ , Atkinson G . Update – Ethical Standards in Sport and Exer-
cise Science Research . Int J Sports Med 2011 ; 32 : 819 – 821
14 Hoeger W W , Hopkins D R . A comparison of the sit and reach and the
modifi ed sit and reach in the measurement of fl exibility in women .
Res Q Exerc Sport 1992 ; 63 : 191 – 195
15 Holt L E , Pelham T W , Burke D G . Modifi cations to the standard sit and
reach fl exibility protocol . J Athl Train 1999 ; 34 : 43 – 47
16 Hui S C , Yuen P Y , Morrow J R Jr , Jackson A W . Comparison of the criterion-
related validity of sit-and-reach tests with and without limb length
adjustment in Asian adults . Res Q Exerc Sport 1999 ; 70 : 401 – 408
17 Kawano M M , Ambar G , Oliveira BI R , Boer M C , Cardoso APR G , Cardoso
J R . Infl uence of the gastrocnemius muscle on the sit-and-reach test
assessed by angular kinematic analysis . Rev Bras Fisioter 2010 ; 14 :
10 – 15
18 Lemmink K A , Kemper H C , de Greef M H , Rispens P , Stevens M . The valid-
ity of the sit-and-reach test and the modifi ed sit-and-reach test in
middle-aged to older men and women . Res Q Exerc Sport 2003 ; 74 :
331 – 337
19 Lericollais R , Gauthier A , Bessot N , Sesboüé B , Davenne D . Time-of-day
eff ects on fatigue during a sustained anaerobic test in well-trained
cyclists . Chronobiol Int 2009 ; 26 : 1622 – 1635
20 Manire J T , Kipp R , Spencer J , Swank A M . Diurnal variation of hamstring
and lumbar fl exibility . J Strength Cond Res 2010 ; 24 : 1464 – 1471
21 Onambele-Pearson NL G , Pearson S J . Time-of-day eff ect on patella ten-
don stiff ness alters vastus lateralis fascicle length but not the quad-
riceps force-angle relationship . J Biomech 2007 ; 40 : 1031 – 1037
22 Ordoñez F J , Rosety-Rodríguez M , Rosety M , Gómez del Valle M , Diaz-
Ordoñez A , Rosety J M , Fornieles-Gonzalez G . Valuation of the infl uence
of the circadian rhythms in the athletic effi ciency of runners . Rev Bras
Cien Mov 2002 ; 10 : 77 – 80
23 Physical Activity Guidelines Advisory Committee report . Washington :
U.S. Department of Health and Human Services ; 2008
24 Ré AH N , Teixeira C P , Massa M , Böhme MT S . The roles of anthropomet-
ric characteristics and physical fi tness in talent identifi cation in
indoor soccer players . Rev Bras Cien Mov 2003 ; 11 : 51 – 56
25 Reilly T , Bambaeichi E . Methodological issues in studies of rhythms
in human performance . Biol Rhythm Res 2003 ; 34 : 321 – 336
26 Reilly T , Atkinson G , Edwards B , Waterhouse J , Farrelly K , Fairhust E .
Diurnal variation in temperature, mental and physical performance,
and tasks specifi cally related to football (soccer) . Chronobiol Int 2007 ;
24 : 507 – 519
27 Ronque ER V , Cyrino E S , Dórea V , Serassuelo-Junior H , Galdi EH G , Arruda
M . Physical fi tness diagnosis in schoolchildren of high socioeconomic
status: evaluation for health criteria . Rev Bras Med Esporte 2007 ; 13 :
71 – 77
28 Sedliak M , Finni T , Cheng S , Kraemer W J , Hakkinen K . Eff ect of time-
of-day-specifi c strength training on serum hormone concentrations
and isometric strength in men . Chronobiol Int 2007 ; 24 : 1159 – 1177
29 Shephard R J . Sleep, biorhythms and human performance . Sports Med
1984 ; 1 : 11 – 37
30 Shrout P E , Fleiss J L . Intraclass correlation: Use in assessing rater reli-
ability . Psychol Bull 1979 ; 86 : 420 – 428
Affi liations
1 Laboratory of Kinesiologic Electromyography and Kinematic , Universidade
Estadual de Londrina , Brazil
2 Physical Therapy Department , Marquette University , Milwaukee ,
United States
3 Physical Therapy Department , Faculdades Integradas Aparício Carvalho ,
Porto Velho , Brazil
4 Master of Science Program in Physical Education , Universidade Estadual de
Londrina , Brazil
Downloaded by: Lenamar Vieira. Copyrighted material.

Page 6

952
Orthopedics & Biomechanics
Guariglia DA et al. Time of Day Eff ect … Int J Sports Med 2011; 32: 947–952
34 Wells K F , Dillon EK . The sit and reach: a test of back and leg fl exibil-
ity . Res Q Exerc Sport 1952 ; 23 : 115 – 118
35 Wing P , Tsang I , Gagnon F , Susak L , Gagnon R . Diurnal changes in the
profi le shape and range of motion of the back . Spine 1992 ; 17 : 761 – 766
36 Zago A S , Gobbi S . Normative values of functional fi tness in women
between 60-to-70 years . Rev Bras Cien Mov 2003 ; 11 : 77 – 86
31 Souissi N , Bessot N , Chamari K , Gauthier A , Sesboüé B , Davenne D . Eff ect
of time of day on aerobic contribution to the 30-s Wingate test per-
formance . Chronobiol Int 2007 ; 24 : 739 – 748
32 Souissi N , Gauthier A , Sesboüé B , Larue J , Davenne D . Eff ects of regular
training at the same time of day on diurnal fl uctuations in muscular
performance . J Sports Sci 2002 ; 20 : 929 – 937
33 Souissi N , Souissi M , Souissi M , Chamari K , Tabke Z , Dogui M , Davenne
D . Eff ect of time of day and partial sleep deprivation on short-term,
high-power output . Chronobiol Int 2008 ; 25 : 1062 – 1076
Downloaded by: Lenamar Vieira. Copyrighted material.