Effect of upright and slouched postures on the diaphragm strength and chest expansion in obese young adults – An Observational Study :BR Ganesh, Christy Tomy, Indian Journal of Physical Therapy and Research

ORIGINAL ARTICLE
Year : 2022 | Volume : 4 | Issue : 2 | Page : 155--158

Effect of upright and slouched postures on the diaphragm strength and chest expansion in obese young adults – An Observational Study

BR Ganesh, Christy Tomy
Department of Cardiovascular and Pulmonary Physiotherapy, KAHER Institute of Physiotherapy, Belagavi, Karnataka, India

Correspondence Address:
Dr. B R Ganesh
Department of Cardiovascular and Pulmonary Physiotherapy, KAHER Institute of Physiotherapy, Belagavi, Karnataka
India

Abstract

Context: Obese individuals are at high risk of adopting slouched posture because of their excessive body fat distribution. Moreover, excess body fat limits the action of the respiratory muscles and restricts diaphragm mobility and rib movement. Aims: The aim of this study was to study the influence of upright versus slouched posture on respiratory muscle strength and chest expansion in obese young adults. Settings and Design: The participants included in the study were young adults of all genders between the age group of 18 and 25 years with a body mass index above 27.5. Methods and Materials: It is an observational study. Thirty participants were recruited from health-care institutions. Screening was done according to the inclusion and exclusion criteria. Diaphragm strength and chest expansion were assessed in upright sitting and slouched sitting postures. Statistical analysis used: SPSS statistical package version 23 was used to analyze the data. Normality of the baseline data was checked using Student's t-test. To summarize the data, descriptive statistics (mean and standard deviation) were employed. To discover variations in maximal inspiratory pressure (MIP) scores and chest expansion between slouched and upright sitting positions, a paired t-test analysis was performed. Results: The participants showed a lower MIP score in slouched sitting as compared to an upright sitting posture. The mean difference in the MIP scores was 20.99 mmHg (P = 0.04). Chest expansion measurements also showed a significant difference between the two sitting postures. Conclusions: The lower maximal inspiratory pressure and chest expansion measures observed in this study indicate that in obese individuals, slouched sitting posture can adversely affect the diaphragm strength and the chest wall mechanics during breathing.

How to cite this article:
Ganesh B R, Tomy C. Effect of upright and slouched postures on the diaphragm strength and chest expansion in obese young adults – An Observational Study.Indian J Phys Ther Res 2022;4:155-158

How to cite this URL:
Ganesh B R, Tomy C. Effect of upright and slouched postures on the diaphragm strength and chest expansion in obese young adults – An Observational Study. Indian J Phys Ther Res [serial online] 2022 [cited 2023 Oct 1 ];4:155-158
Available from: https://www.ijptr.org/text.asp?2022/4/2/155/368053

Full Text

Introduction

One of the health problems increasing at a rapid rate worldwide is obesity. Overweight is described as increased weight proportional to the height of the subject.[1] The global prevalence of overweight population is 1.9 billion and 650 million are obese. In India, the prevalence of obesity is 135 million.[2]

“Posture is defined as the position in which body must be held to stay upright, balancing the effects of gravity through muscular interaction.“[3] A slouched sitting posture is a relaxed posture also called reversible postural kyphosis occurs when there is an overall kyphotic curve of the entire thoracic spine along with an anterior pelvic tilt. It is a relaxed posture where the person relies on only the passive structures to provide stability by yielding to the effects of gravity. The main cause of this posture may be attitudinal, fatigue, or muscle weakness which may be a cause or effect of posture.[1] Obese individuals are at high risk of adopting this posture because of excessive body weight. These static sedentary postures can cause continuous contraction of neck and shoulders as well as decrease the ability of chest wall and diaphragm to expand.[4]

According to the length–tension relationship, the capability of a muscle fiber to create active tension is influenced by muscle length. Therefore, it can be assumed that any change to the ribcage due to posture that may alter this relationship in the respiratory muscles, mainly the diaphragm, can result in reduced muscle strength and consequently affecting the depth and rate of breathing.[3],[6]

The diaphragm contracts during regular breathing, moving the abdominal contents downward and forward. At the same moment, the external intercostal muscles contract, pulling the ribs upward and forward.[4],[8] In obese individuals, this mechanism is impaired because the accumulation of fat is present in and around the ribs, the diaphragm, and the abdomen. This extra body fat restricts diaphragmatic movement and rib mobility, which promotes alterations in the dynamics of the respiratory system and lowers compliance, resulting in mechanical impairment of the respiratory muscles.[2],[4] In other words, to produce the same amount of ventilation, obese subjects need more diaphragmatic activity than normal subjects. In clinical settings, determining the optimal body position is of utmost importance when administering respiratory physical therapy as it highly influences the performance of respiratory muscles.[1],[5] Many studies have studied the long term effects of slouched posture, but our study analyses the immediate effects of posture on respiratory mechanics.

Subjects and Methods

Data for this cross-sectional study were collected from obese young adults of all genders residing in Belagavi city, India.

The participants included in the study were young adults of all genders between the age group of 18 and 25 years with a body mass index (BMI) above 27.5. Participants diagnosed with any spinal deformities and any obstructive or restrictive lung diseases were excluded from this study. After screening, informed consent was taken from each participant. Ethical approval was gained from the Institutional Ethical Committee of KAHER Institute of Physiotherapy, Belagavi, India.

Outcome measures

Maximum inspiratory pressure

It measures the strength of the inspiratory muscles, particularly the diaphragm. It was measured using a handheld pressure manometer in the units of mmHg.

Thoracic and axillary cirtometry

It consists of measuring the difference in the chest circumference during maximal inspiration and maximal expiration. It is measured at two levels: the anterior axillary line and the xiphoid process.

Procedure

The study's goal was stated, and all volunteers provided written informed permission. Once the subjects were selected and screened as per inclusion and exclusion criteria, they were oriented to the devices used in the study. A stadiometer was used to record the height and weight to determine the BMI in kilograms per square meter. The two different postures that were to be assumed by the participant during the study were explained clearly.

In the upright posture, participants were asked to sit with an upright head and straight back and shoulder back and relaxed with feet resting on the floor. In slouched sitting, participants were asked to assume relaxed and habitual sitting with a forward head, rounded shoulders with a flat back, and feet resting on the floor. Each posture was maintained only for a short period until the readings were obtained as this study only aimed to analyze the immediate effect of posture. In each posture, the participant was asked to take a quick maximal inspiration from the residual capacity after maximal expiration using the mouthpiece of the pressure manometer by completely sealing their lip around the mouthpiece. A nose clip was used if necessary. This maneuver will be repeated three times, and the average was calculated. A break time of 5 min was provided each time before switching posture to avoid fatigue. Randomization of the two sitting postures was done to avoid the order effect. Chest expansion was measured at two levels: anterior axillary line and xiphoid process with the 0 points of the tape maintained at the midline. Measurements were taken at the end of maximum inspiration and maximal expiration, and the difference was calculated. Two readings were taken at each level, and the average was obtained for both sitting postures separately. All instruments were sanitized, and proper hygiene was maintained before using on the next participant. Finally, the data obtained will be statistically analyzed to determine the effect of slouched and upright posture the muscle strength and chest expansion.

Results

A total of 33 participants participated in the study with a mean age of 21 (range: 18–25) and a BMI of 28.83 kg/m2. Sample size calculation was done based on the power of the test formula. 27.5 kg/m2 was set as the cutoff for obesity according to the Asia-Pacific classification of BMI. The details of demographic variables are given in [Table 1]. [Table 2] presents the comparison of the MIP scores in a normal upright position and slouched sitting position.{Table 1}{Table 2}

The data were analyzed using SPSS statistical software version 23. The normality of the baseline data was checked using Student's t-test. To summarize the data, descriptive statistics (mean and standard deviation) were employed. To discover variations in MIP scores and chest expansion between upright and slouched sitting positions, a paired t-test analysis was performed. The statistical significance limit was established at 0.05 for hypothesis testing. The participants showed a lower MIP score in slouched sitting as compared to an upright sitting posture. The mean difference in the MIP scores was 20 mmHg (P = 0.04) [Table 2]. In addition, a significant difference in difference in the means of the MIP readings between males and females was also observed (P = 0.05). Chest expansion measurements also showed a significant difference between the two sitting postures, as shown in [Table 3]. The axillary chest expansion showed a mean difference of 0.96 cm (P = 0.001), and thoracic chest expansion showed a difference of 1.11 cm (P = 0.001).{Table 3}

Discussion

The present study aimed to evaluate the effects of sitting posture on diaphragm strength and chest expansion in obese young adults. Maximal inspiratory mouth pressure and chest cirtometry were used as the outcome measures. The results of this study showed that there is a significant correlation between sitting posture and lung biomechanics in obese young adults.

In obese individuals, the normal respiratory mechanism is impaired because of structural changes to the thoracoabdominal area caused by extra body fat that borders the chest and surrounds the abdomen. These structural changes limit the action of respiratory muscles and restrict rib movement and diaphragmatic mobility, which promotes changes in the dynamics of the respiratory system, resulting in mechanical dysfunction of the respiratory muscles. Sarikaya et al. found that subjects suffering from obesity have lower MIP values than subjects with a normal BMI (P = 0.01).[6]

Position, range of motion, and coupling patterns of the spinal and rib articulations are affected by any changes to postural alignment by influencing the compliance through changing the articular range of motion available for respiration.[7] Any change in rib cage compliance, whether caused by passive or active processes, can impact the biomechanics and recruitment of respiratory muscles, and hence the motion of the chest wall.[8]

The reduced MIP values of subjects in slouched posture in our study are similar to a study done by Albarrati et al.[9] to measure the respiratory strength using sniff nasal inspiratory pressure in a normal male population. Lee et al. (2010) discovered differences in the thoracic and abdominal cavity features in different habitual sitting postures using respiratory inductive plethysmography.[10] Another study conducted in the same year on healthy females showed significantly higher values of PImax and PEmax in upright sitting positions when compared to semi-upright and supine positions.[11],[12]

This study showed a lower mean difference in MIP in men as compared to women. The impact of different fat distributions on thoracic activity varied; central obesity dramatically reduced diaphragm and chest activity, but peripheral obesity had only a minor influence on respiratory movement. Because fat distribution differs between men and women, it stands to reason that gender differences in fat distribution, in addition to gender differences in lung architecture and hormones, contribute differentially to lung functions for men and women.[13]

The present study also demonstrated an increase in chest expansion in the upright posture compared to the slouched sitting posture. The alignment of the thoracic spine due to its rib attachments has a close relationship with the expansion capabilities of the rib cage during inhalation.[14]

The present study has some potential limitations. The sample size was small and lacks homogeneity of gender. The degree of slouch was not quantified as it may vary from person to person.[15] The body fat composition and deposition have not been measured in this study. Further studies can be done on a larger population along with a comparative group of nonobese subjects. The fitness level of the individual may have an effect of the respiratory parameters and muscle strength; therefore, the inclusion of a fitness assessment tool is recommended.

Conclusion

The lower maximal inspiratory pressure and chest expansion measures observed in this study indicate that in obese individuals, slouched sitting posture can adversely affect the diaphragm strength and the chest wall mechanics during breathing. Further studies can be done to observe the effect of correcting postural malalignment on the respiratory system.

Acknowledgments

The authorship team would like to thank all the participants of this study.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1	Colby L, Borstad J, Kisner C. Improved Mobility. Therapeutic Exercise: Foundations and Techniques 2017:82.
2	Ahirwar R, Mondal PR. Prevalence of obesity in India: A systematic review. Diabetes Metab Syndr 2019;13:318-21.
3	Barroso AT, Martín EM, Romero LM, Ruiz FO. Factors affecting lung function: A review of the literature. Arch Bronconeumol (English Edition) 2018;54:327-32.
4	Han J, Park S, Kim Y, Choi Y, Lyu H. Effects of forward head posture on forced vital capacity and respiratory muscles activity. J Phys Ther Sci 2016;28:128-31.
5	Mishra S, Kiran UV. Posture discomfort due to laptops among college going students. Int J Humanit Soc Sci Invent 2013;2:14-6.
6	Sarikaya S, Cimen OB, Gokcay Y, Erdem R. Pulmonary function tests, respiratory muscle strength, and endurance of persons with obesity. Endocrinol 2003;13:136-41.
7	Edmondston SJ, Aggerholm M, Elfving S, Flores N, Ng C, Smith R, et al. Influence of posture on the range of axial rotation and coupled lateral flexion of the thoracic spine. J Manipulative Physiol Ther 2007;30:193-9.
8	Cappello M, De Troyer A. Role of rib cage elastance in the coupling between the abdominal muscles and the lung. J Appl Physiol (1985) 2004;97:85-90.
9	Albarrati A, Zafar H, Alghadir AH, Anwer S. Effect of upright and slouched sitting postures on the respiratory muscle strength in healthy young males. Biomed Res Int 2018;2018:3058970.
10	Lee LJ, Chang AT, Coppieters MW, Hodges PW. Changes in sitting posture induce multiplanar changes in chest wall shape and motion with breathing. Respir Physiol Neurobiol 2010;170:236-45.
11	Jyothi NS, Kumar GY. Effect of different postures on peak expiratory flow rate and peak inspiratory flow rate on healthy individuals. Int J Phys Educ Sports Health 2015;1:42-5.
12	Costa R, Almeida N, Ribeiro F. Body position influences the maximum inspiratory and expiratory mouth pressures of young healthy subjects. Physiotherapy 2015;101:239-41.
13	Huang L, Ye Z, Lu J, Kong C, Zhu Q, Huang B, et al. Effects of fat distribution on lung function in young adults. J Physiol Anthropol 2019;38:7.
14	Jang HJ, Kim MJ, Kim SY. Effect of thorax correction exercises on flexed posture and chest function in older women with age-related hyperkyphosis. J Phys Ther Sci 2015;27:1161-4.
15	Sembulingam K, Sembulingam P. Essentials of medical physiology. JP Medical Ltd; 2012.