Observing the effect of physical activity on forward head posture and rounded shoulder posture in young healthy adults

Abstract

[Purpose] This study aimed to examine the effects of physical activity on forward head and rounded shoulder postures in healthy young adults. [Participants and Methods] We recruited 20 healthy young adults engaged in high levels of physical activity and 20 healthy young adults engaged in low levels of physical activity. Both groups completed the International Physical Activity Questionnaire (IPAQ) to assess their physical activity levels. The scapular index (SI) was calculated to assess rounded shoulder posture, whereas the craniovertebral angle (CVA) was calculated to assess forward head posture. Differences in SI and CVA between the two groups were examined. [Results] There was a significant difference in the SI between the two groups, with the low physical activity group exhibiting a lower SI than the high physical activity group. However, there was no significant difference in the CVA between the two groups. [Conclusion] Our study showed that low physical activity levels in healthy young adults could negatively affect shoulder posture but not head posture. Therefore, regularly monitoring rounded shoulder posture in individuals with low physical activity levels is recommended for health considerations.

INTRODUCTION

With the advancement of technology and changes in lifestyle and work types, insufficient physical activity among modern people has become increasingly serious. Several studies have demonstrated that healthy young adults with low physical activity exhibit poor musculoskeletal health^{1, 2)}. Bassey and Harries suggested that reduced physical activities are often accompanied by poor musculoskeletal health, including a decline in muscle mass, strength, explosive power, and endurance¹⁾. Curtis indicated that increased physical activity could improve musculoskeletal performance and reduce the incidence of related musculoskeletal disorders²⁾. Moreover, Armstrong mentioned that nearly one-third of young adults in their twenties have insufficient physical activity per week, which becomes more severe as they age³⁾. All these findings indicate that a lack of regular exercise, in turn, leads to insufficient physical activity, which is particularly common among young adults. Sedentary adults tend to experience faulty postures, including rounded shoulders and forward head postures⁴⁾. Additionally, Erdem and Akbaş suggested that reduced physical activity and poor posture in daily life may lead to musculoskeletal abnormalities⁵⁾. Jacobs et al. mentioned that the main cause of reduced physical activity might be a sedentary lifestyle over a long period⁶⁾. Moreover, Ruivo showed that incorrect posture could cause the center of gravity (COG) of the body not to be positioned properly, thereby affecting the muscle torque for posture control and changing the joint angles, causing improper tension or pressure on the joints, which can lead to musculoskeletal system injuries over time⁷⁾. Greenfield et al. indicated that rounded shoulder posture is a common risk factor for musculoskeletal shoulder changes⁸⁾. Previous research has also indicated that a rounded shoulder posture can cause scapular movement dysfunction⁹⁾. Theoretically, a rounded shoulder posture can cause excessive forward displacement of the shoulder joint, leading to overstretching of the muscles located behind the shoulder joint and adaptive shortening of the muscles located in front of the shoulder joint¹⁰⁾. In addition, individuals with a forward head posture are more likely to exhibit incorrect scapular kinematics, such as scapular-internal rotation and -anterior tilt, when compared than individuals with proper head posture¹¹⁾. From the literature reviewed above, it was found that rounded shoulder and forward head postures are likely associated with the level of physical activity. As individuals increase the time spent on sedentary activities, their level of physical activity also decreases. Improper sitting postures during prolonged sitting may cause abnormal bone alignment and exacerbate rounded shoulder posture.

We hypothesized that healthy young adults with low physical activity levels are more likely to develop rounded shoulders and forward head postures than those with high physical activity levels. This study aimed to analyze the impact of physical activity levels on the rounded shoulder and forward head postures in healthy young adults.

PARTICIPANTS AND METHODS

Forty healthy young adults were recruited from the university and were divided into two groups based on their physical activity levels. According to the clinically meaningful differences and variability estimates from Salahzadeh et al., 2014’s study¹²⁾, a sample size of 20 participants per group can provide 80% power to detect an effect size of 0.85 between 2 groups of craniovertebral angle at an alpha level of 0.05 with a two-tailed test using G-power. The high physical activity group (20 individuals) comprised healthy young adults with a total physical activity level of >3,000 metabolic equivalents (METs) per week, while the low activity group (20 individuals) comprised healthy young adults with a total activity level of ≤3,000 METs per week¹³⁾. Participants with neck pain, shoulder pain, fractures, or any musculoskeletal or neurological disease were excluded from the study. Ethical approval for this study was obtained from the National Cheng Kung University Human Research Ethics Committee (approval no: NCKU HREC-111-053-2). All participants provided written informed consent before participation.

Each participant underwent physical activity measurements using the International Physical Activity Questionnaire (IPAQ). The questionnaire asked participants to recall their physical activity levels in the past week for low-intensity activities (sitting and walking), moderate-intensity activities (cycling at a regular pace and swimming), and high-intensity activities (running and playing sports) to obtain their physical activity scores¹³⁾. Macfarlane indicated that this measurement method is highly reliable (ICC=0.79)¹⁴⁾. The rounded shoulder posture was determined using the scapular index (SI), which was measured using a digital caliper in the standing position. Notably, the distance from the midpoint of the sternal notch (SN) to the medial aspect of the coracoid process (CP) and the horizontal distance from the posterolateral angle of the acromion (PLA) to the thoracic spine (TS) was measured. The SN-to-CP distance correlates highly with pectoralis minor muscle length, reflecting a rounded shoulder posture¹⁵⁾. The SI was calculated using the equation [(SN to CP/PLA to TS) ×100]¹⁵⁾. Carvalho et al. showed that this measurement method has high reliability (ICC=0.77)¹⁶⁾. The forward head posture was measured using the craniovertebral angle (CVA). The CVA was determined as the point at which a horizontal line passing through the spinous process of C7 intersected with a line connecting the midpoint of the tragus of the ear to the skin above the spinous process of C7¹²⁾. When the cervical angle was lower, it demonstrated that the forward head posture was more severe¹²⁾. A previous study indicated that this measure has high reliability (ICC=0.91)¹⁷⁾. The participants were initially assessed using the IPAQ and then categorized into high- and low-PA groups. A team of trained physical therapists performed the measurements. Subsequently, both groups underwent rounded shoulder and forward head postures measurements using the SI and CVA.

Statistical analysis was performed using SPSS 22 software (SPSS Inc, Chicago, IL, USA). An independent t-test was used to examine whether there were any differences in SI and CVA between the two groups of participants (high and low physical activity levels). The Shapiro–Wilk test was conducted to examine whether the data were normally distributed. Non-parametric statistics were used when the data were non-normally distributed. The significance level was set at p<0.05.

RESULTS

Twenty healthy young adults (21.28 ± 0.71 years) with high physical activity levels (9,827 ± 6,280 metabolic equivalent; METs/week) and 20 healthy ones (21.18 ± 1.22 years) with low physical activity levels (1,691 ± 757 METs/week) were recruited in this study (Table 1). There was a significant difference in SI between the two groups (p=0.023). Moreover, the low physical activity group (SI=66.75 ± 5.97) showed lower SI than the high physical activity group (SI=70.72 ± 3.43). However, there was no significant difference in the CVA between the two groups (p=0.345) (Table 2).

Table 1. Descriptive statistics of participants.

	Low physical activity group (n=20)	High physical activity group (n=20)
Gender
Female (Male)	13 (7)	10 (10)
Age (years)	21.18 ± 1.22	21.28 ± 0.71
Physical activity (METs/week)	1,691 ± 757	9,827 ± 6,280*

*p<0.05. MET: metabolic equivalents of task.

Table 2. Independent t-test for SI and CVA.

	Low physical activity group (n=20)	High physical activity group (n=20)
SI	66.75 ± 5.97	70.72 ± 3.43*
CVA (°)	52.87 ± 5.20	49.30 ± 6.19

*p<0.05. SI: scapular index; CVA: craniovertebral angle.

DISCUSSION

We investigated the influence of physical activity on rounded shoulders and forward head postures in healthy young adults. Following our study, we observed that low physical activity levels in healthy young adults could negatively affect shoulder posture but not head posture. Previous studies compared posture assessments between high physical activity groups (athletes) and moderate to low physical activity groups (healthy individuals with prolonged sitting), and the results showed that the moderate to low activity group had poorer posture assessments than the high physical activity group⁵⁾. A possible reason for this is that when the level of physical activity is higher, individuals are less likely to remain in the same position for a prolonged period, resulting in better muscle flexibility and improved chest mobility⁴⁾. However, the level of physical activity did not have an impact on the forward head posture. This study only measured forward head posture in the standing position and not in the sitting position; there may be different results when measuring forward head posture in the sitting position. Kim et al. discovered in their study that participants had a smaller craniovertebral angle while in a seated position as compared to a standing position¹⁸⁾. Therefore, future studies should compare the effects of forward head posture in both standing and sitting positions. In addition, previous studies have suggested that there may be a significant association between forward head posture and the degree of thoracic kyphosis¹⁹⁾. Singla et al. proposed that forward head posture, rounded shoulders, and increased thoracic kyphosis may occur independently or in various combinations¹⁹⁾. These three deviations can trigger a cascade of biomechanical changes, whereby one of the deviations can lead to the other two. Therefore, future studies should include measurements of the angle of thoracic kyphosis to investigate further the potential relationship between the magnitude of the thoracic kyphosis angle and head posture. The limitations of this study are that the participants were limited to healthy young college students, and the sample size was small which may limit the results to other age groups. Summarily, in healthy young adults, low physical activity levels could negatively affect shoulder posture but not head posture. Hence, for health considerations, regular checks of the rounded shoulder posture in participants with low physical activity are necessary.

Conflict of interest

None.