Sit-to-stand ground reaction force characteristics in blind and sighted female children

Accepted Manuscript Title: Sit-to-stand ground reaction force characteristics in blind and sighted female children Authors: Mozhgan Faraji Aylar, Amir Ali Jafarnezhadgero, Fatemeh Salari Esker PII: DOI: Reference:

S0966-6362(18)30135-8 https://doi.org/10.1016/j.gaitpost.2018.03.004 GAIPOS 5985

To appear in:

Gait & Posture

Received date: Revised date: Accepted date:

26-6-2017 20-2-2018 3-3-2018

Please cite this article as: Faraji Aylar Mozhgan, Jafarnezhadgero Amir Ali, Salari Esker Fatemeh.Sit-to-stand ground reaction force characteristics in blind and sighted female children.Gait and Posture https://doi.org/10.1016/j.gaitpost.2018.03.004 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Sit-to-stand ground reaction force characteristics in blind and sighted female children “Original Article”

Mozhgan FarajiAylara*, AmirAli Jafarnezhadgerob, Fatemeh SalariEskerc a

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Division of Biomechanics, Department of Mechanical Engineering, Sahand University of

Thechnology, Tabriz, Iran.

Departments of Physical Education and Sport Science, Faculty of Educational Sciences and

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Psychology, University of Mohaghegh Ardabili, Ardabil, Iran.

Department of Sports Biomechanics, University of Mazandaran, Babolsar, Iran. E-mail:

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[email protected]

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*Corresponding author: Mozhgan Faraji Aylar, Division of Biomechanics, Department of Mechanical Engineering, Sahand University of Technology, Sahand New Town, Tabriz, Iran (Postcode: 51335-1996, Tel. +98-41-23443801, Fax +98-41-33449490, E-mail [email protected])

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Acknowledgements

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We thank all of the subjects who participated in the study.

Abstract word count: 227 Text word count: 2991

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Highlights Posteriore force in congenitally blind group was higher than permanently blind group.

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Loading rate in congenitally blind group was greater than permanently blind group.

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Vertical impulse in permanently blindness group was greater than eyes open group.

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Vertical impulse in congenitally blind group was lower than eyes open group.

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Restricted vision is associated with balance control difficulty.

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Abstract

Background: The association between visual sensory and sit-to-stand ground reaction force

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characteristics is not clear. Impulse is the amount of force applied over a period of time. Also,

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free moment represents the vertical moment applied in the center of pressure (COP).

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Research question: How the ground reaction force components, vertical loading rate,

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impulses and free moment respond to long and short term restricted visual information?

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Methods: Fifteen female children with congenital blindness and 45 healthy girls with no

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visual impairments participated in this study. The girls with congenital blindness were placed in one group and the 45 girls with no visual impairments were randomly divided into three

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groups of 15; eyes open, permanently eyes closed, and temporary eyes closed. The participants in the permanently eyes closed group closed their eyes for 20 minutes before the

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test, whereas temporary eyes closed group did tests with their eyes closed throughout, and

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those in the eyes open group kept their eyes open. Results: Congenital blindness was associated with increased vertical loading rate, range of motion of knee and hip in the mediolateral plane. Also, medio-lateral and vertical ground reaction force impulses. Similar peak negative and positive free moments were observed in three groups. Significance: In conclusion, the results reveal that sit-to-stand ground reaction force components in blind

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children may have clinical importance for improvement of balance control of these individuals.

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Key words: Postural control, Congenital blindness, Children, Vision, Sit-to-stand

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1. Introduction Visual impairment is an important public health concern[1]. According to a report published by World Health Organization in 2010, 19 million children suffered from visual impairments[2]. Visual impairment has been demonstrated to negatively affect different aspects of life, including functional status and quality of life[3]. The children needed visual

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rehabilitation interventions for full psychological and personal development[4].

Visual system plays an important role in adjusting postural orientation of the body[5]. It

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appears that visually impaired children suffer from a deficiency of the sensory information

provided by the visual system. This can predispose them to challenges with balance and

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difficulties with coordination of all body segments and make it hard to perform motions and

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functions that depend on balance, such as sit-to-stand(STS).

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Congenitally blind(CB) people theoretically use two models for perception of spatial

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information in the development of hearing, deficit, and compensation models. The deficit

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model claims that non-visual data is normally encoded within a visual spatial frame of

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reference, and individuals lacking such a reference system will have impaired spatial hearing. The compensation model argues that, in the absence of typical visual senses, non-visual

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regions of perception may become more highly developed than in sighted people[6]. Parts of the visual cortex of blind people are recruited by other sensory modalities to process sensory

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information in a cross-modal manner[7]. Volgyi et al.[8] reported that the compensatory effect is much greater if deprivation occurs early in life. Also, the early damage to visual

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circuitry has long lasting effects on movement and balance. Petersen et al.[9] and Einarsson et al.[10] demonstrated that obscure visual processing at a young age manifests as long-term disruptions with standing balance. Therefore, the possibility that CB children performed balance movements better than acquired blind children seems a possible assumption.

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Therefore, we hypothesized that the time of visual restricted memory can influence the kinetic parameters of these subjects. Previous studies have shown that lack of visual feedback during functional movement can lead to balance disorders[11], different sensorimotor strategies[12], sensory integration

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disorders, and lack of visual feedback during functional movement. In addition, a recent study by Siriphorn et al.[13] confirms that blind individuals have problems with STS. For

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example, blind individuals demonstrated lesser weight transfer time, a greater center of

gravity sway[13], muscle weakness relative to healthy individuals, and need for greater help when performing the STS task. Moreover, it is reported that constrained visual sense is

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independently associated with weight bearing ability, center of mass(COM) velocity[14], and

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rising index[13].

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The STS movement is a fundamental determinant of functional fitness[15], most

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mechanically demanding tasks[16], and a prerequisite for walking. The postural control

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system must continually update to prevent falling during STS maneuver. Therefore,

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biomechanical variables of the STS have clinical significance and are used to provide feedback that are useful for evaluating the treatment results or for designing the rehabilitation

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programs. It was reported that healthy children exhibited more variability in their STS patterns than adults[17]. By nine to ten years of age, the STS movement patterns were similar

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to the patterns of healthy adults[17]. Therefore, there are a few studies that detected the STS

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patterns of 8 year olds. In addition, many studies exhibited that subjects’ age has a major influence on the kinematics and kinetics[18] of STS task. According to these studies, present investigation especially focused on participation’s age(94.6 months). Dark adaptation for the visual system is the process of adjusting to total darkness or to lower levels of illumination. The time of rod intercept reported is less than or equal to 20 min,

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usually 8.2 min[19] and 12.5 min[20], in young and elderly people, respectively. Therefore, in this study, the time of the eyes being closed was set 20 minutes to ensure the occurrence of rod intercept. The consolidation process of a new motor memory may take several hours or, under certain situations, minutes[21]. Therefore, this study aimed to determine if the consolidation process occurs during rod intercept, or if it occurred only during long term

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constrained visual information.

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STS ground reaction forces(GRFs) and their time to peak(TTP), vertical loading rate, impulses and free moment(FM) are among the most important kinetic variables that could

affect a functional movement. Impulse is a well-accepted measurement that is obtained from

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GRFs, which combine the amount of force applied over a period of time. Also, the FM

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represents the vertical moment applied in the COP and is considered to be sensitive to the

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movement and the imbalances of the whole body in the transverse plane. Few studies have

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focused on STS analysis of visual constrained sensory[13, 14], rather than calculating of STS GRF characteristics, which can indicate one noticeable step toward understanding visual

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rehabilitative trainings and interventions could possibly help improve physical functioning.

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The objective of the present study was to analyze the GRFs, their TTP, loading rate,

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impulses, and FM during STS in CB, eyes closed(EC), and eyes open(EO) children. We hypothesized that time of visual restricted information(short and long term) is associated with

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altered biomechanical strategies of STS.

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2. Methods

2.1. Participants Forty five female children, with permission of their parents, participated in this study. CB children were selected from blind schools(Taghva) in Mashhad, Iran. In this experiment,

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blindness is defined as visual acuity of less than 3/60 (20/400 or 0.05) or corresponding field no greater than 10 in the better eye, with best possible correction[4]. Fifteen of the girls suffered from CB. The remaining 45 girls were healthy and did not have any visual impairment. These 45 healthy girls were divided into three groups (Table 1). The

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subjects in the(permanently blindness)PEC group closed their eyes for 20 minutes before the STS test, while the(acute or temporary blindness)TEC group performed tests with their eyes

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closed throughout. The EO group kept their eyes open. During the practice and real trials, the

subjects in the PEC group kept their eyes closed to prevent any learning taking place through the use of visual information. The healthy girls had no musculoskeletal or neuromuscular

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problems and were considered normally active. In addition, the participants’ mobility and

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balance was evaluated by the timed-up-and-go-test(TUG) and the Tinetti-mobility-

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test(TMT)[22](Table 1).

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Dominant limb was determined as the limb used to kick a ball[23]. Ethics approval was

Table 1 here

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obtained from the research council of the International University of Imam Reza.

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2.2 Instruments and examination

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2.2.1. STS kinematics

An eight camera video-based opto-electronic system(Qualisys AB, Sweden) was used for

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three dimensional motion capture(with sampling rate equal to 100Hz). The motion data was filtered using a fourth order Butterworth filter with a cutoff frequency of 10Hz. Retroreflective markers were placed over bony landmarks including the vertex, seventh cervical vertebra(C7), and spinous process of the twelfth thoracic vertebrae. Markers were also placed bilaterally on the: lateral borders of the acromion process, greater humeral tubercle, olecranon 7

processes of the ulna, heads of the styloid process of the ulna, anterior superior iliac spines(ASIS), posterior superior iliac spines(PSIS), greater trochanter, lateral femoral epicondyles, lateral malleoli, 5th metatarsal heads, and calcaneal tuberosity. The height of the chair was adjusted to 100% of each subject’s leg length. During the STS test, the participants placed one foot on each force plate for 3 to 4 sec; their arms were folded across the chest. The

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subjects sat with their bodies and extremities symmetrically placed relative to the chair, and

the distance between the feet was determined as the ASIS width. Also, the feet positions were

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parallel. The subjects were instructed to raise their entire body from the chair at a self-

selected velocity. Each subject was requested to perform five STS trials with 30-second rests

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between the trials. Upper extremity markers were used to define STS events. Markers on the

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olecranon processes and heads of the styloid process of the ulna were used to monitor the

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arms folded across the chest. Seven segments (trunk, right and left thighs, right and left legs

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and foots) were defined to calculate whole body center of mass(BCOM). The task of STS was defined by three events:(1) the beginning of the movement when the

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border of the acromion process marker began to move forward in the anterior-posterior

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plane,(2) the seat-off event when the initiation of knee flexion began, and(3) the end of the

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STS task was defined as the maximum height of the shoulder marker. According to these events, there were two phases, the preparation phase(PP) and the standing phase(SP)(Table

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1).

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2.2.2. STS kinetics Two adjustable force plates(9260AA6, Kistler, Switzerland) with a sampling frequency of 1000Hz were used to record the GRFs data. The GRF data was filtered using a fourth order Butterworth filter with cutoff frequency of 10Hz. The GRF values were recorded along vertical(z), medio-lateral(x), and anterior-posterior(y) directions(Fig.1). The vertical GRF

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curve, contains one peak on the preparation point(FzPP) and a minimum amplitude on the standing point(FzSP). Moreover, on the anterior-posterior curve, two peaks were recorded at the preparation point(FyPP) and standing point(FySP). From the medio-lateral curve also, three values were recorded corresponding to the preparation point which occurred initially(FxPP), followed the peak at the middle(FxMS) and minimum amplitude on the standing point(FxSP) at

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the final part of curve. Loading rate was defined as the slope between the initial and FzPP on vertical GRF curve(Fig.1). Impulse was calculated for all axes based on the trapezoid

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)) + ∑𝑛−1 𝑖=2 𝐹𝑖

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The FM amplitude was also calculated as a follow[25]:

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𝐹1 +𝐹𝑛

Impulse=∆𝑡 ((

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integration method[24]as a follow:

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Free moment=Mz+(Fx×COPy)-(Fy×COPx)

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Where, Mz is the moment about the vertical axis; x and y are the linear components of the

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COP; Fx and Fy (anterior-posterior GRFs) are the linear components of the GRF.

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Figure 1 here

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2.3. Statistical analysis

A Multivariate analysis of variance(MANOVA) test with Bonferroni’s post hoc test was used

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for between group comparisons. Alpha level was set at p<0.05. Statistical analysis was performed using the SPSS 19.0® software. The effect sizes(d) were calculated as a ratio of

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mean difference divided by the mean standard deviation of both groups. 3. Results The

BCOM

velocity

demonstrated

significant

interaction

between

group

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condition(P=0.019).In anterior-posterior and vertical axes, the mean BCOM velocity in PEC 9

group was lower by 61%(p=0.011,d=1.61) and 69%(p=0.030,d=1.41) than those in healthy group, respectively. In medial-lateral axis, the peak BCOM velocity in TEC group were lower by 48%(p=0.024,d=1.08) than that in CB group. The joints range of motion (ROM) in all planes had significant interaction between group and

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condition(P=0.037). On dominant side, knee ROM of EO group was lesser than those in PEC and CB groups(by 43%(p=0.001,d=1.62) and 45%(p=0.024,d=1.24), respectively) and

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medio-lateral hip ROM of EO group was lower than that in CB group(by 52%(p=0.034,d=1.19)). On non-dominant side, anterior-posterior hip ROM of EO group was greater than that in CB group(by 97%(p=0.024,d=0.21)).

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Measures of balance and mobility tests have demonstrated that there were significant

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interaction between group and condition(P=0.000). The timed-up-and-go-test values of EO

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group was greater than those in PEC, TEC, and CB groups by 44%(p=0.000,d=5.29),

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66%(p=0.000,d=2.17), and 38%(p=0.000,d=5.01), respectively. Furthermore, the Tinetti-

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mobility-test balance of EO group was higher than those in TEC, PEC, and CB groups by

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85%(p=0.000,d=3.02), 76%(p=0.000,d=3.56), and 69%(p=0.000,d=4.27), respectively. Also, the Tinetti-mobility-test balance in the TEC group was about 81%greater than that in the CB

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group (p=0.001, d=1.78). The Tinetti-mobility-test gait of EO group was higher than those in TEC, PEC, and CB groups by 88% (p=0.006, d=1.60), 74% (p=0.000, d=2.94), and

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63%(p=0.000,d=4.25), respectively. Also, the Tinetti-mobility-test total of EO group was than

those

in

TEC,

PEC,

and

CB

groups

by

86%(p=0.000,d=2.95),

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higher

75%(p=0.000,d=4.35), and 66%(p=0.000,d=5.11), respectively. The Tinetti-mobility-test total of TEC group was greater than those in PEC and CB groups by 87%(p=0.004,d=1.41) and 77%(p=0.000,d=2.32), respectively(Table 1). Table 1 here

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On both sides, peak GRF amplitudes in Fz, Fy, and Fx were similar among the four groups (P˃0.05) (Table 2). Table 2 here On the non-dominant side, time to peak amplitudes demonstrated significant interaction

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between group and condition(P=0.013). Time to peak for FxSP in PEC group were significantly greater by 58%(p=0.037,d=1.45) than that in EO group. Time to peak for FzPP

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and FzSP in PEC group were significantly greater by 58%(p=0.010,d=1.05) and 77%(p=0.037,d=0.90) respectively than that in CB group(Table 3).

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Table 3 here

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On the non-dominant side, vertical loading rate of CB group was significantly greater than

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that in EO group(p=0.004,d=0.33)(Fig.2A,B). In addition, impulse values among all groups

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were different on the non-dominant side(P=0.022)(Fig.2D). On the non-dominant side, the x and z impulses of PEC group were significantly greater than that EO group(p=0.001,d=1.58

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and p=0.004,d=1.42 respectively)(Fig. 2C,D). The FM values of both phases showed no significant differences among all

Fig. 2 here Fig. 3 here

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groups(p˃0.05)(Fig. 3C,D).

3. Discussion It was hypothesized that the time constraint of visual sensory is associated with altered GRF characteristics.

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In the present study, the GRFs of all groups were similar. Foot rotation is a critical factor for hip rotation and knee extension regarding the hip ROM. At age of eight, the femoral torsion changes and it can affect the kinematic strategy. Also, the foot angle is important for the medial-lateral and anterior-posterior parameters of the GRFs and the FM[25, 26]. In the present experiment, the start angle and feet ROM in all of groups were similar. Therefore,

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altered GRF components may not be associated with these parameters. Start point of the hip reflects use of hip moments to generate horizontal momentum in the phase I of STS[27]. We

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found that individuals with long term restricted visual information prefer greater knee and hip

ROM(dominant side) in the medio-lateral plane and lower hip ROM(non-dominant side) in

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anterior-posterior plane than the healthy individuals. In the medio-lateral plane, individuals

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with short term restricted visual information(PEC group) prefer greater knee ROM(dominant

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side) than the healthy individuals. The present study demonstrated that the lack of long and

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short term visual sensory can influence the ROM of hip and knee joints. The total TMT values of CB, PEC, and TEC groups have under 24 and they are at risk for

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falls and have poor performance[22]. The TMT gait in the PEC group was higher than CB

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group. It could be due to the fact that difference of current activity level and experience of

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CB children with PEC and TEC groups. For example, CB children may be less active and reluctant to go from sitting to standing without physical support. Generally, the performance

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of TEC group was better than PEC group, and PEC children were better than CB group

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during balance and mobility tests. In the present study, there were significant differences in the TTP of FzPP, FzSP and FxSP(nondominant side) between groups. Also, TTP for FxSP in PEC group was higher than those in the EO group. These prove the hypothesis of this study and reveal that, the time restriction of visual information alters the timing of GRF components. This work provides the first reference database of STS GRF characteristics in CB and acquired blind female children. 12

Previous studies have been demonstrated balance disorders in these individuals[12]. These findings may give further support to the hypothesis that the timing of the GRF elements will fluctuate fundamentally among the healthy, congenitally-blind, and PEC children. We found that PEC children prefer smaller BCOM velocity than the healthy children during

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STS movements in anterior-posterior and vertical axes. These may be due to fear of falling. Similar vertical GRF during smaller BCOM velocity in PEC group may be associated with

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higher proximal joints load[28]. A greater effort in the PEC children could be expected to

push the body center of mass forward within the anterior-posterior plane. But, the results of the present study did not demonstrate any significant differences for Fy components between

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PEC and EO groups. Kuramastu et al.[14] reported that sighted individuals with closed eyes

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have no significant differences with the healthy group in COM velocity during STS task.

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These differences in results may be associated with differences in neurobehavioral

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mechanisms between the EO and eyes closed condition, participant’s age range[29] and the

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duration of eye closure in the eyes closed condition.

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In this study, when individuals experienced blindness more than 94 months, they demonstrated a greater vertical loading rate in their non-dominant side. It has been claimed

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that the vertical loading rate is a critical parameter for evaluating the overload of lower limb musculoskeletal tissues[30]. It was identified that a greater vertical loading rate(about 10% of

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BW) is a risk of future injuries; therefore, it can be concluded that lack of long term visual

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information can predispose a person to future injuries. However, further study is warranted on these patients, especially during activities such as walking and running. Furthermore, on non-dominant side, the values of medio-lateral and vertical impulses in PEC group were significantly higher than that in the EO group. Also, we found that the subjects with constrained visual data exhibited a similar magnitude of negative and positive peaks of

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FM compared to the healthy individuals. We were not able to find other studies addressing this issues. The number of subjects of the present study was relatively small. However, the study had sufficient power on statistical tests to detect the between group differences. This study did not

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address the muscle activities during STS in different groups. Further studies are suggested to combine the measurements of different muscle activities with kinetic analysis during

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walking, running, and STS activities. Conclusion

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Greater middle peak of medio-lateral ground reaction force and medio-lateral impulse in the

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congenitally-blind and eyes-closed groups may possibly be a risk factor that could lead to

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disturbing the medio-lateral body motion during sit-to-stand maneuver. The consolidation

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process did not occur completely during long term visual restricted sensory. But, the rate of consolidation process of new motor memory in long term visual constrained information was

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higher than rod intercept, which is defined as the time for a participant’s visual sensitivity to

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recover to a stimulus intensity of 5×10-3 cd/m2. The analysis of congenitally-blind children’s ground reaction force components demonstrated that they have difficulties in medio-lateral

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and vertical axes on both sides of their lower extremities. Therefore, this study suggests that

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future rehabilitation to address loading asymmetries during sit-to-stand could help to avoid future disability in congenitally-blind individuals.

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Conflict of interest statement None of the authors have any conflicts of interest in relation to the work reported here. Funding

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This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

References

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[1] Kodjebacheva, Damianova G. Visual impairment and myopia among first graders from

three school districts in Southern California: Racial/ethnic disparities, yearly trends,

determinants: University of California, Los Angeles; 2009.

SC R

geospatial distribution, and relative influence of individual, neighborhood, and school

U

[2] WHO. World Health Statistics 2010. World Health Organization; 2010.

N

[3] Finkova D, Joklikova H. Information and the Quality of Life of Visually Impaired

A

Individuals. Procedia - Social and Behavioral Sciences. 2014;112:1099-105.

Ophthalmology. 2012;96:614-8.

M

[4] Pascolini D, Mariotti S. Global estimates of visual impairment: 2010. British Journal of

D

[5] Horak F. Postural orientation and equilibrium: what do we need to know about neural

TE

control of balance to prevent falls? Age and Ageing. 2006;35:ii7-ii11. [6] Giagazoglou P, Amiridis I, Zafeiridis A, Thimara M, Kouvelioti V, Kellis E. Static

EP

balance control and lower limb strength in blind and sighted women. European Journal of

CC

Applied Physiology. 2009;107:571-9. [7] Théoret H, Merabet L, Pascual-Leone A. Behavioral and neuroplastic changes in the

A

blind: evidence for functionally relevant cross-modal interactions. Journal of PhysiologyParis. 2004;98:221–33. [8] Völgyi B, Farkas T, Toldi J. Compensation of a sensory deficit inflicted upon newborn and adult animals. A behavioural study. NeuroReport. 1993;4:827-9.

15

[9] Petersen H, Patel M, Ingason EF, Einarsson EJ, Haraldsso A, Fransson P-A. Long-term effects from bacterial meningitis in childhood and adolescence on postural control. PLoS One. 2014;9:e112016. [10] Einarsson E-J, Patel M, Petersen H, Wiebe T, Fransson P-A, Magnusson M, et al. Decreased postural control in adult survivors of childhood cancer treated with chemotherapy.

IP T

Scientific Reports. 2016;6:36784.

[11] Singh NB, Taylor WR, Madigan ML, Nussbaum MA. The spectral content of postural

SC R

sway during quiet stance: Influences of age, vision and somatosensory inputs. Journal of Electromyography and Kinesiology. 2012;22:131-6.

U

[12] Anjos Fd, LemosLuís T, Imbiriba A. Does the type of visual feedback information

N

change the control of standing balance? European Journal of Applied Physiology.

A

2016;116:1771–9.

M

[13] Siriphorn A, Chamonchant D, Boonyong S. The effects of vision on sit-to-stand movement. Journal of Physical Therapy Science 2015;27:83–6.

D

[14] Kuramatsu Y, Muraki T, Oouchida Y, Sekiguchi Y, Izumi S-I. Influence of constrained

2012;36:90–4.

TE

visual and somatic senses on controlling centre of mass during sit-to-stand. Gait & Posture.

EP

[15] Highsmith MJ, Kahle JT, Carey SL, Lura DJ, Dubey RV, Csavina KR, et al. Kinetic

CC

asymmetry in transfemoral amputees while performing sit to stand and stand to sit movements. Gait & Posture. 2011;34:86–91.

A

[16] Manckoundia P, Mourey F, Pfitzenmeyer P, Papaxanthis C. Comparison of motor strategies in sit-to-stand and back-to-sit motions between healthy and Alzheimer’s disease elderly subjects. Neuroscience. 2006;137:385–92. [17] Cahill BM, Carr JH, Adams R. Inter-segmental co-ordination in sit-to-stand: an age cross-sectional study. Physiotherapy Research International. 1999;4:12-27.

16

[18] Ikeda ER, Schenkman M, Riley PO, Hodge WA. Influence of age on dynamics of rising from a chair. Physical Therapy. 1991;71:473-81. [19] Jackson GR, Edwards JG. A short-duration dark adaptation protocol for assessment of age-related maculopathy. Journal of Ocular Biology, Diseases, and Informatics. 2008;1:7–11. [20] Holfort SK, Jackson GR, Larsen M. Dark adaptation during transient hyperglycemia in

IP T

type 2 diabetes. Experimental Eye Research. 2010;91:710–4.

[21] IYa P. Possibility of "superfast" consolidation of long-term memory. Membrane & cell

SC R

biology. 1998;11:743-52.

[22] Camara-Lemarroy CR, Ortiz-Zacarías D, Peña-Avendaño JJ, Estrada-Bellmann I,

U

Villarreal-Velázquez HJ, Díaz-Torres MA. Alterations in balance and mobility in people with

N

epilepsy. Epilepsy & Behavior. 2017;66:53-6.

A

[23] Jafarnezhadgero AA, Majlesi M, Azadian E. Gait ground reaction force characteristics in

M

deaf and hearing children. Gait & Posture. 2017;53:236-40. [24] Robertson G, Caldwell G, Hamill J, Kamen G, Whittlesey S. Research Methods in

D

Biomechanics, 2E: Human Kinetics; 2013.

TE

[25] Almosnino S, Kajaks T, Costigan PA. The free moment in walking and its change with foot rotation angle. Sports Med Arthrosc Rehabil Ther Technol. 2009;1.

EP

[26] Farahpour N, Jafarnezhad A, Damavandi M, Bakhtiari A, Allard P. Gait ground reaction

CC

force characteristics of low back pain patients with pronated foot and able-bodied individuals with and without foot pronation. Journal of biomechanics. 2016;49:1705-10.

A

[27] Mak MKY, Levin O, Mizrahi J, Hui-Chan CWY. Joint torques during sit-to-stand in healthy subjects and people with Parkinson's disease. Clinical Biomechanics. 2003;18:197206. [28] Winter DA. Biomechanics and motor control of human movement. 4 ed: John Wiley & Sons; 2009.

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[29] Costa CSND, Rocha NAC. Sit-to-stand movement in children: A longitudinal study based on kinematics data. Human Movement Science. 2013;32:836–46. [30] Liikavainio T, Bragge T, Hakkarainen M, Karjalainen PA, Arokoski JP. Gait and muscle

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activation changes in men with knee osteoarthritis. The Knee. 2010;17:69–76.

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Figure captions

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Fig. 1. A time-normalized sample traces of the ground reaction forces of a normal subject during STS task. Reaction forces and impulse area in all axes and vertical loading rate are

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displayed. Seat-off event is indicated by the solid vertical line.

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Fig. 2. (A) Vertical loading of dominant side, (B) Vertical loading of non-dominant side, (C)

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Impulse values of dominant side, and (D) Impulse values of non-dominant side in the

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congenitally blind (CB), permanent eyes closed (PEC), temporary eyes closed (TEC), and

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eyes open (EO) groups.*: When compared to the eyes open condition (p<0.05).

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Fig. 3. (A) Negative and positive peaks of free moment curve of dominant side, (B) Negative and positive peaks of free moment curve of non-dominant side, (C) the free moment of

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dominant side, and (D) the free moment of non-dominant side in the congenitally blind (CB),

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permanent eyes closed (PEC), temporary eyes closed (TEC), and eyes open (EO) groups

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during phase 1 and phase 2.

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Table 1 Demographic characteristics of congenitally blind (CB), permanent eyes closed (PEC), temporary eyes closed (TEC), and eyes open (EO) children. Groups Sig. CB PEC TEC EO 15 15 15 15 NA N 94.60 ± 5.59 93.80 ± 5.89 94.00 ± 7.05 95.80 ± 5.54 0.777 Age (month) 25.74 ± 2.12 24.16 ± 1.35 26.68 ± 4.22 26.06 ± 5.22 0.229 Mass (Kg) 1.27 ± 0.05 1.24 ± 0.04 1.26±.04 1.26 ± 0.04 0.334 Height (m) 16.13 ± 2.55 15.66 ± 0.83 16.37 ± 1.52 16.11 ± 2.05 0.728 BMI Female Female Female Female NA Gender 36.62 ± 1.59 0.35 ± 0.01 36.16 ± 1.55 0.001 34.56 ± 1.13*,a Leg length (cm) a a a 17.76 ± 1.23 0.000 15.84 ± 0.64 0.16 ± 0.00 16.46 ± 0.95 ASIS width (cm) R R R R 0.581 Foot dominant side 0.36 ± 0.23 0.44 ± 0.23 0.36 ± 0.09 0.40± 0.17 0.658 Phase I duration of STS task 0.84 ± 0.36 1.21 ± 0.52 1.06 ± 0.57 0.75± 0.26 0.027 Phase II duration of STS task 1.21 ± 0.41 1.66 ± 0.51 1.43 ± 0.57 1.15 ± 0.25 0.014 Total duration of STS task -106.20 ± 50.56 -81.95 ± 21.91* -114.81 ± 45.21 -133.89 ± 42.55 0.011 BCOM velocity AP(mm/s) 12.47 ± 20.51 1.30 ± 18.84 -1.97 ± 14.56 5.97 ± 16.85 0.148 BCOM velocity ML(mm/s) 143.40 ± 56.71 106.13 ± 26.26* 135.38 ± 45.53 152.11 ± 38.81 0. 030 BCOM velocity VT(mm/s) 36.31 ± 86.32 -2.47 ± 20.17 -11.61 ± 23.81 0. 087 Peak BCOM velocity AP(mm/s) 4.23 ± 53.83 a 83.21 ± 47.27 46.62 ± 32.42 58.07 ± 44.63 0. 024 40.56 ± 31.38 Peak BCOM velocity ML(mm/s) 423.17 ± 130.84 350.93 ± 83.04 411.36 ± 143.70 474.65 ± 119.06 0. 059 Peak BCOM velocity VT(mm/s) 81.58 ± 5.15 78.17 ± 8.18 81.82 ± 7.29 83.09 ± 6.16 0.242 Start D (º) Sag. ankle 88.43 ± 9.96 92.22 ± 4.86 91.75 ± 5.73 95.26 ± 7.55 0.098 knee 109.52 ± 12.44 110.68 ± 12.70 103.48 ± 5.83 106.03 ± 8.33 0.213 hip 128.81 ± 24.98 24.98 ± 27.23 122.07 ± 23.55 133.27 ± 21.84 0.439 Fron. ankle 159.10 ± 15.72 158.24 ± 12.13 164.97 ± 12.84 170.15 ± 7.94 0.039 knee 149.41 ± 48.64 153.74 ± 37.30 169.29 ± 5.30 169.44 ± 6.16 0.177 hip 9.57 ± 6.81 10.87 ± 8.05 10.17 ± 7.58 9.31 ± 8.29 0.947 Trans. ankle 6.51 ± 5.67 12.25 ± 8.97 12.40 ± 9.50 14.27 ± 11.91 0.130 knee 63.58 ± 49.76 52.99 ± 48.93 31.15 ± 28.78 37.74 ± 27.75 0.125 hip 78.09 ± 7.45 81.54 ± 9.59 84.30 ± 8.10 86.98 ± 9.47 0.044 Start ND (º) Sag. ankle 90.14 ± 5.84 90.76 ± 6.21 92.94 ± 5.16 95.92 ± 9.45 0.102 knee 98.92 ± 22.58 97.84 ± 6.90 104.60 ± 5.73 100.62 ± 9.15 0.508 hip 123.20 ± 29.77 136.77 ± 24.12 140.86 ± 26.67 157.13 ± 15.53 0.005 Fron. ankle 163.02 ± 11.52 158.57 ± 11.35 163.68 ± 13.36 161.73 ± 17.21 0.739 knee 159.30 ± 29.24 159.19 ± 10.92 164.91 ± 13.37 164.12 ± 14.44 0.745 hip 11.84 ± 9.83 11.95 ± 10.54 12.91 ± 14.58 24.12 ± 30.85 0.210 Trans. ankle 14.89 ± 8.74 10.70 ± 6.50 12.69 ± 8.39 20.19 ± 33.53 0.520 knee 39.22 ± 25.71 28.42 ± 22.40 30.14 ± 20.85 37.74 ± 22.86 0.487 hip 13.06 ± 3.39 13.32 ± 5.47 11.03 ± 4.84 10.80 ± 5.69 0.365 ROM D (º) Sag. ankle 68.15 ± 6.97 71.62 ± 7.13 65.28 ± 5.43 66.08 ± 8.08 0.071 knee 71.36 ± 11.93 78.20 ± 9.81 75.75 ± 10.58 79.04 ± 7.90 0.173 hip 20.02 ± 13.20 20.09 ± 12.59 23.19 ± 18.88 23.03 ± 20.47 0.917 Fron. ankle 23.55 ± 13.73* 24.81 ± 10.47* 16.88 ± 11.96 10.77 ± 6.82 0.003 knee 16.25 ± 9.35* 21.62 ± 11.63 12.48 ± 4.67 11.34 ± 5.49 0.005 hip 22.33 ± 10.20 21.60 ± 14.48 18.03 ± 4.61 20.56 ± 7.56 0.656 Trans. ankle 27.87 ± 23.78 65.83 ± 55.04 30.45 ± 31.76 34.61 ± 46.70 0.051 knee 46.66 ± 32.20 66.61 ± 46.17 42.39 ± 35.66 56.34 ± 48.46 0.387 hip 14.60 ± 3.60 12.99 ± 4.92 11.16 ± 3.68 11.27 ± 4.53 0.095 ROM ND (º) Sag. ankle 68.31 ± 5.48 73.41 ± 9.09 67.52 ± 4.93 66.84 ± 10.04 0.093 knee 66.35 ± 17.80* 17.80 ± 7.02 76.51 ± 9.87 79.34 ± 9.83 0.018 hip 22

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ankle knee hip

20.87 ± 13.94 18.44 ± 8.59 14.06 ± 9.75

19.21 ± 14.38 22.18 ± 8.89 21.53 ± 8.97

14.79 ± 6.87 17.40 ± 10.51 17.23 ± 11.33

17.87 ± 12.72 20.99 ± 15.42 18.90 ± 13.13

0.585 0.628 0.307

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ankle knee hip

19.47 ± 13.05 34.50 ± 43.10 44.61 ± 35.02 20.49 ± 3.88* 10.80 ± 1.74* 7.20 ± 1.20* 18.00 ± 2.72*

29.85 ± 23.83 46.12 ± 40.81 27.44 ± 15.14 17.55 ± 2.50* 12.00 ± 1.51*

21.16 ± 12.24 28.00 ± 21.48 33.35 ± 20.84

29.05 ± 31.20 31.07 ± 36.82 42.70 ± 20.85 7.88 ± 1.15 15.60 ± 0.50 11.26 ± 0.70 26.86 ± 0.74

0.440 0.553 0.182 0.000 0.000 0.000 0.000

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11.93 ± 2.56*, a, b TUG (s) 13.26 ± 1.03*, a TMT balance (s) ,a 8.40 ± 1.24* 9.93 ± 0.96*, a, b TMT gait (s) 20.40 ± 2.22* 23.20 ± 1.74*, a, b Total TMT (s) Note: Values are mean ± standard deviation. Abbreviations: N, number of participants; BMI, body mass index; R, right; ASIS, anterior superior iliac spine; NA, not applicable; BCOM, whole body center of mass; AP, anterior-posterior axis; ML, medial-lateral axis; VT, vertical axis; TUG, timed up and go test; TMT, Tinetti mobility test; ROM, range of motion; Sag, sagittal plane; Fron, frontal plane; Trans, transverse plane. * p<0.05 when compared to the eyes open group. a p<0.05 when compared to the congenitally blind group. b p<0.05 when compared to the eyes closed group.

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Table2 GRF (%BW) of Z, Y, and X axes in different STS points for control and experimental group in dominant (D) and non-dominant (ND) sides are presented. Data are (mean ± SD). GRF Groups Congenital blindness Permanent eyes closed Temporary eyes closed Eyes open D ND D ND D ND D ND -4.54 ±2.07 4.49 ±2.65 -5.38 ± 1.95 5.49 ±1.72 -5.46 ± 1.39 5.02 ± 1.51 -5.14 ± 1.85 4.64 ±1.97 FxPP -2.73 ±3.30 3.79 ±3.55 -2.03 ±1.55 2.71 ±2.28 -1.36 ± 1.81 1.56 ± 1.76 -1.37 ±1.19 1.16 ±1.18 FxMS -4.01 ±2.78 3.18 ±2.24 -4.49 ±1.55 4.59 ± 1.76 -4.32 ± 1.64 4.15 ± 1.69 -3.64 ±1.48 4.85 ±1.31 FxSP -3.04 ±5.32 -1.61 ±3.89 -4.34 ±3.62 -3.20 ±3.25 -6.27 ± 3.77 -3.43 ± 3.85 -7.36 ±3.24 -4.51 ±3.33 FyPP 3.21 ±3.92 2.89 ± 2.75 4.48 ±2.64 3.52 ±2.72 5.65 ± 4.06 3.26 ± 2.92 6.49 ±3.18 5.69 ±2.76 FySP FzPP 67.67 ±10.31 61.71 ±9.84 60.98 ±8.57 59.36 ±6.52 61.16 ± 10.70 55.83 ± 8.97 64.30 ±11.70 57.08 ±10.90 FzSP 38.60 ±16.50 34.35 ±18.98 38.38 ±15.25 41.22 ±6.61 35.59 ± 20.26 30.38 ± 10.66 33.14 ±13.97 31.92 ±11.91 * p<0.05 when compared to the eyes open group.

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Table3 The time to peak (second) of GRF components for congenitally blind, permanent eyes closed, temporary eyes closed, and eyes open groups in dominant (D) and non-dominant (ND) sides. Data are (mean ± SD). GRF Groups Congenital blindness Permanent eyes closed Temporary eyes closed Eyes open D ND D ND D ND D ND 0.27 ± 0.10 0.28 ± 0.18 0.29 ± 0.15 FxPP 0.29± 0.17 0.29 ± 0.17 0.37± 0.21 0.33 ± 0.25 0.28 ± 0.10 0.53± 0.18 0.62± 0.31 0.62± 0.31 0.53 ± 0.21 0.53 ± 0.16 0.45± 0.15 0.44 ± 0.15 FxMS 0.51± 0.27 0.75 ±0 .30 0.80 ± 0.23* 0.91± 0.41 1.00 ± 0.41 0.79 ± 0.32 0.79 ± 0.27 0.59 ± 0.17 0.58± 0.14 FxSP 0.33 ± 0.09 0.33 ± 0.17 0.33± 0.15 FyPP 0.28± 0.17 0.25 ± 0.17 0.37± 0.19 0.35 ± 0.19 0.33 ± 0.09 0.53 ± 0.08 0.51± 0.18 0.53 ± 0.19 FySP 0.56± 0.20 0.54 ± 0.24 0.62± 0.26 0.59 ± 0.24 0.54 ± 0.10 0.38± 0.20 0.56± 0.19 0.65 ± 0.31a 0.45 ± 0.17 0.53 ± 0.17 0.46± 0.17 0.48± 0.18 FzPP 0.42± 0.24 a 0.82± 0.23 0.78 ± 0. 20 1.02 ± 0.28 1.01± 0.30 0.85 ± 0.21 0.91 ± 0.15 0.89± 0.16 0.86 ± 0.19 FzSP * p<0.05 when compared to the eyes open group. a p<0.05 when compared to the congenitally blind group.

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