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 Table of Contents  
Year : 2021  |  Volume : 15  |  Issue : 2  |  Page : 63-66

Sway amplitude during foam and dome test in typical young adults

1 Lecturer, Department of Pediatrics, JSS College of Physiotherapy, Mysore, Karnataka, India
2 Associate Professor, Department of Musculoskeletal and Sports Physiotherapy, JSS College of Physiotherapy, Mysore, Karnataka, India
3 Assistant Professor, MGM Hospital and College of Physiotherapy, Navi Mumbai, Maharashtra, India

Date of Submission29-Sep-2021
Date of Decision20-Nov-2021
Date of Acceptance24-Nov-2021
Date of Web Publication15-Feb-2022

Correspondence Address:
Mr. V Vijay Samuel Raj
Department of Musculoskeletal and Sports Physiotherapy, JSS College of Physiotherapy, MG Road, Mysore - 570 004, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/pjiap.pjiap_28_21

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INTRODUCTION: Balance is one of the most important components for an individual to be in a good state of health condition. The functional balance is most important for the individual to maintain the equilibrium, and the characteristics of the task may increase or decrease the difficulty of the balance component. There is a need to obtain normative sway variabilities (angle, distance, and frequency) in different planes among young adults, which may be used in clinical and sports for balance evaluation and training.
MATERIALS AND METHODS: Repetitive measure design was used to identify the normative values of foam and dome test on the typical young adults. The sway variabilities of the typical young adults were evaluated through standardized foam and dome test. The anterior-posterior (AP) and mediolateral sway angle and distance were measured using Kinovea software at six phases on a postural grid and results were analyzed using range, mean, and standard deviation.
RESULTS: Seventy-six participants, 50 females and 26 males were recruited (mean age 21.5 ± 15 years). The mean sway angle with eyes open (EO), eyes closed (EC), with dome, on foam with dome, on foam with EO, on foam with EC in AP plane was 4.15 ± 1.57, 8.09 ± 2.56, 10.47 ± 2.88, 18.42 ± 4.27, 9.15 ± 2.22, and 17.6 ± 5.38,°, respectively. The mean sway results were consistent in similarity with the angle, and frequency.
CONCLUSION: The study concludes that the sway amplitude values obtained using foam and dome test showed that the angle, distance, and the number of sways increase with the alteration in the sensory input.

Keywords: Balance, clinical test of sensory integration and balance, equilibrium, postural, sway amplitude, trunk sway

How to cite this article:
Shivanna Gowda PH, Samuel Raj V V, Mishra SS. Sway amplitude during foam and dome test in typical young adults. Physiother - J Indian Assoc Physiother 2021;15:63-6

How to cite this URL:
Shivanna Gowda PH, Samuel Raj V V, Mishra SS. Sway amplitude during foam and dome test in typical young adults. Physiother - J Indian Assoc Physiother [serial online] 2021 [cited 2022 May 21];15:63-6. Available from: https://www.pjiap.org/text.asp?2021/15/2/63/337720

  Introduction Top

Balance is one of the most important components for human beings to be in good health condition. “The balance is defined as the proportionate distribution of the weight enabling someone or something to be in the state of equilibrium.” In the human body, the center for balance is the cerebellum, which plays an important role in controlling the movement through its vestibular and spinal connections. The cerebellum is responsible for maintaining the equilibrium of the body.[1] The balance is controlled mainly by the three systems, the visual system, vestibular system, and somatosensory system. The visual system contributes 20% by detecting the self's motion regarding the stationary environment. The vestibular system contributes 10% by giving inputs of the head's movement and position. The somatosensory system contributes 70% by providing information regarding the body regarding the supporting surface.[2]

The functional balance is most important for the individual to maintain equilibrium. The functional balance has task constraints and environmental context. The characteristics of the task may increase or decrease the difficulty of the balance component. Both of these have the information processing aspects and the biomechanical aspects, which work in a closed circuit to maintain the balance. The constraints form the task, and the environment affects the motor performance in two ways,[2] alter the balance demands by altering the activity's biomechanical features. Second, it affects the amount of information that must be processed to achieve the balance and motor goal.[3]

The balance comprises postural control, and equilibrium control relates to maintaining the body's intersegmental stability and its parts despite the forces acting on it and can be achieved by the three mechanisms, including proactive mechanism, predictive mechanism, and reactive mechanism. The proactive balance mechanism is based on the visual system. The predictive balance mechanism maintains intersegmental stability within the body and between the body and the support surface. The reactive mechanism consists of short and long latency postural reflexes of a type appropriate to the particular stimulus.[4]

Postural control is influenced by physiological factors, psychological factors, psycho-physiological factors, and training factors. The postural sway oscillates body movement over the feet, where COG places a vital role. The observable normal sway with feet 4 inches apart in anteroposterior (AP) is approximately 12°, and medio-lateral (ML) sways is 16°.[5] An increase in sway angle can indicate balance impairment. Foam and dome test is commonly used to determine abnormal postural sway and balance impairment. It is the simplified method for investing the organization of multiple sensory inputs in postural control. The test is performed in six different conditions by modulating the sensory inputs. Studies have shown the estimation of postural sway by using the clinical test of sensory integration and balance foam and dome test is an effective tool to interpret balance impairment in diabetic peripheral neuropathy, and the elderly population.[6] Postural sway can estimate the risk of falls in the elderly population. Literature is scarce about normative values of foam and dome test in typical young adults. This study aims to determine the normative values of postural sway using foam and dome test on the typical young adults.

  Materials and Methods Top

Repetitive measure research design was conducted on typical young adults, The typical young adults defined operationally as “a person between the ages of 20 and 25, with no underlying disease or deformities and typically having similarities between the groups and within the normal body mass index (BMI) range.” Participants both males and females, with a BMI of between 18.5 and 24 kg/m2 and the duration of the study was for 6 months, between February and July 2016. The visual acuity was limited to a person having a normal vision of 6/6. College students who met the criteria were selected randomly and allocated for the sequence using the chit method after explaining the study procedures and obtaining informed consent. The participants were screened for systemic illness, vestibular dysfunction, lower limb musculoskeletal injuries and dysfunction, cardiorespiratory and neurological disorders, using a questionnaire. The participants with any of these disorders were excluded from the study. Screening for the exclusion criteria was done using a standard self-reported questionnaire, PAR-Q, and by physical examination. The sample size was determined using “G” power software, with P value of 0.05 (estimated proportion of the population), z = 1.96 (The probability of falsely rejecting a true null hypothesis), E = 10% (margin of error). Data analysis was performed using SPSS version 17.00 (SPSS Inc, Released 2008, SPSS Statistics for Windows, Version 17.0. Chicago: SPSS Inc.). The mean and standard deviation of age, sway angle in degrees, sway length in millimeters (mm), and sway number in numeric digits were calculated for all six phases.


The authors obtained permission and clearance from the authorities and institutional research and ethical committee with written informed consent from the participants. A comfortable sports dress outfit for all participants was recommended. The quiet examination room was prepared with appropriate light without any reflection and good ventilation to be distraction-free. The time of examination was selected between 4 pm to 6 pm. A pilot study was carried out, and corrections were appropriately made before the study.

The evaluation consists of two postural charts placed perpendicular to each other and the plumb lines placed at the center of the chart with a distance of 68 cm from the postural chart. The postural charts with the horizontal and vertical grids with the area of 3 cm2 were used in the background to assess the posture. For video recording, two cameras (Canon camera 3.09 megapixels and a focal length of 3.67–73.4 mm), placed at a standard height adjusted based on the participant's height used. The participant was positioned at the center of the postural chart and plumb line at a distance of 34 cm. Camera-1 was placed in such a way that the camera was parallel to the participant, the plumb line “a” and postural chart “A” with a distance of 196 cm from the participant (34 cm away from the postural chart) and 126 cm away from the floor in corresponding to the height. This covered the entire three components to record the ML sway for each participant. The camera-2 was positioned in such a way that the camera was parallel to the participant, the plumb line “b” and postural chart “B” with a distance of 196 cm from the participant (34 cm away from the postural chart) and 126 cm away from the floor in corresponding to a height which covered the entire three components and will record the AP sway of each participant. The sway variations were recorded in six phases, with the constant position throughout the procedure. Each procedure was measured with a rest period of 15 min between each phase. The six phases were eyes open on firm surface (EO), eyes closed on firm surface (EC), with the dome on firm surface), with dome on foam, EC on foam, EO on foam with dome. X and Y-sway velocity along X and Y axis (mm/s2), VM (velocity moment (mm/s2); AP displacement (mm); mediolateral (ML) displacement (mm).


Participants received instruction and were made to stand on the floor between the postural grid. The plumb line with arm crossed across the chest and hand touching the shoulders with the feet positioned together, forming a narrow support base. The participants were encouraged to maintain the position for 30 s.

A 12-inch height polyethylene foam with a density of 0.88–0.96 g/cm3 was used. The dome provides a blockage in the sensory input by blocking the peripheral vision and introduces the sway. A readily available helmet was used, which was prechecked and standardized.

Statistical analysis

The procedures were recorded in the required three phases, and Kinovea version 0.8.26 software was used to analyze the sway angle, distance, and the number of sways by keeping the plumb line and postural chart as a reference point. The data obtained from the Kinovea software were plotted in Microsoft Excel and analyzed using SPSS version 17.00 for the range, the mean and standard deviation of sway angle, sway length, and sway count (number per 30 s).

  Results Top

Seventy-six (n = 76) participated in the study with a mean age of 21.5 ± 1.5 years. Fifty were female participants with the mean age of 22 ± 1.2 and 26 male participants with the mean age of 22.6 ± 1.7. The sway variations were analyzed in the AP and ML sway angle measured in degrees, AP sway distance in millimeters, and Number of AP sway per 30 s in digits. This was carried out in six phased with EO, EC, stable platform, and foam. The normative range for the typical adult participants is depicted in [Table 1].
Table 1: Sway angle, distance, and frequency at six phases in mediolateral and anteroposterior direction with means (standard deviation, ranges)

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  Discussion Top

The study's purpose was to estimate the normative value for the sway amplitude during foam and dome test in typical young adults. The sway amplitude was analyzed using a postural grid. Through video recordings, the sway angle was measured in degrees, and the sway distance in millimeters, number of sways in 30 s duration. The sway evaluation was done in A-P and M-L direction. The normative range for AP view of the postural sway in EO component with a rigid surface is 7.44–17.14 mm, and for the ML view with EO component on a rigid surface is 6.42–16.36 mm. In EC component with the rigid surface, AP sway distance is 16.14–32.66 mm and for the ML sway distance is 14.08–29.26 mm. With the dome component on a rigid surface, AP sway distance is 22.7–40.06 mm, and ML sway distance is 17.55–36.29 mm. Dome component on the foam surface, the AP sway amplitude is 42.42–68.1 mm and ML sway amplitude is 30.52–53.78 mm. In the EO component on the foam surface, AP sway amplitude is 20.81–34.13 mm, and ML sway amplitude is 14.15–29.03 mm. In the EC component on the foam surface, AP sway amplitude is 36.66–68.96 mm, and the ML sway amplitude is 28.76–56.04 mm.

The primary outcome was to evaluate the balance and balance affection with the visual disturbances. From the above results, we can say that balance is affected mainly in young individuals' absence of vision. In diabetic neuropathy patients, the ML displacement with EO and EC (rigid surface), EO and EC (foam surface) was 0.22 ± 0.11 mm, 0.19 ± 0.14 mm, 0.29 ± 0.08 mm, 0.26 ± 0.18 mm, and AP displacement were 0.41 ± 0.09 mm, 0.45 ± 0.10 mm, 0.44 ± 0.11 mm, 0.46 ± 0.22 mm, respectively.[7] In this study, we have included healthy young adults. The sway recorded in young adults is more compared to diabetic neuropathy patients. One of the reasons stated in the study by Dixit et al. was the progression of the disease that makes them adapt to changes that occur physiologically. This process can be well-supported that posture control and balance could be adopted by training and learning. The present study included only typical young adults with no other comorbidities. Impaired postural stability in diabetic neuropathy patients, and the sway worsens with off vision.[7] This study recorded an increase in sway amplitude among female participants than males. Studies have shown that 70% of the Bharatanatyam dancers had flat foot developed due to repetitive load and practice in the learning phase in the early age of life and increases the pressure loading of the ankle and foot complex leading to variation in balance. This was beyond the scope as this study included all typical adults with no musculoskeletal disorders.

A study conducted by Macedo et al., on old age vestibular disorder patients, on foam firm surface-open eyes, firm surface-closed eyes, unstable surface-open eyes, unstable surface-closed eyes, and unstable surface-closed eyes, unstable surface-visual dome found an increase in sway amplitude in all the phases when compared to normal old age patients without vestibular disorders.[8] In adjunct to the above, this study age group involved was typical young adults without impairment. However, there was no variation with age. The mean number of sways on comparing all the test phases for medial-lateral sway was 6.64, and 6.13 times per 30 s in AP sway. This study results can also be taken as initial normative values of sway variation, which can have more clinical outputs for impaired individuals' balance.

  Conclusion Top

The study showed that the sway amplitude, sway angle, and the number of sways increase with sensory input reduction. The balancing on the foam surface with the vision occluded was one of the most difficult phases faced by all participants. There was an increase in sway amplitude among female participants in all phases compared with male participants. Furthermore, studies with more subjects and inclusion of males and females separately may be required to obtain the normative values for typical young adults.


The study results can be used as a reference to assess the balance impaired individual in the clinical setting between the age of 20 and 25 years, a normative reference can be used in the Indian population.


The study's limitation was that the sample size was too small to find a normative value in typical young adults. There was no preanalysis done for balance for the participants before commencing the study. Furthermore, the study comprised more female participants than males, with a ratio of 2:1. The results may have variations due to gender bias. As the study was conducted with the age limit, it cannot be generalized for all the population.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Pritha SB, Lakshmi R, KS. Inderbir Singh's Textbook of Human Neuroanatomy (Fundamental and Clinical). 9th ed. New Delhi, India: Jaypee Brothers Medical Publishers (P) LTD; 2014.  Back to cited text no. 1
Massion J. Postural control system. Curr Opin Neurobiol. 1994;4:877-87  Back to cited text no. 2
Kim JW, Eom GM, Kim CS, Kim DH, Lee JH, Park BK, et al. Sex differences in the postural sway characteristics of young and elderly subjects during quiet natural standing. Geriatr Gerontol Int 2010;10:191-8.  Back to cited text no. 3
Montgomery CP, Connolly BH. Clinical applications for motor control. Aust J Physiother 2013;18:423-44.  Back to cited text no. 4
Kisner C, Borstad J, Colby L. Therapeutic Exercise. 6th ed. Philadelphia, PA: F A Davis; 2012.  Back to cited text no. 5
Cohen HS, Mulavara AP, Peters BT, Sangi-Haghpeykar H, Bloomberg JJ. Standing balance tests for screening people with vestibular impairments. Laryngoscope 2014;124:545-50.  Back to cited text no. 6
Dixit S, Maiya A, Shasthry BA, Kumaran DS, Guddattu V. Postural sway in diabetic peripheral neuropathy among Indian elderly. Indian J Med Res 2015;142:713-20.  Back to cited text no. 7
[PUBMED]  [Full text]  
Macedo C, Gazzola JM, Ricci NA, Doná F, Ganança FF. Influence of sensory information on static balance in older patients with vestibular disorder. Braz J Otorhinolaryngol 2015;81:50-7.  Back to cited text no. 8


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