INTRODUCTION:

Rounded shoulder posture is one of the most common structural anomalies of the shoulder complex¹. Rounded shoulder posture or forward shoulder posture is defined as a postural alignment in which the acromion process sits forward, positioned anterior to the body’s line of gravity². Rounded shoulder posture [RSP] can be related to repetitive overhead activities, backpack carriage, bad habit, mouth breathing, computer/laptop uses, mobile use and prolonged study hours. The RSP leads to muscle imbalance in the form of shortening of anterior shoulder muscles such as pectoralis minor, serratus anterior and upper trapezius and lengthening of posterior shoulder muscles, middle and lower trapezius and rhomboids³. In RSP, the shoulder is placed anterior to the plump line and the position of scapula changes⁴. The pectoralis minor is the only scapulothoracic muscle with both origin and insertion anterior to the scapula. The pectoralis minor muscle is considered an antagonist to the necessary scapular motions during arm elevation⁵.

The pectoralis minor muscle originates from the third to fifth ribs near their junction with the sternum and insertion at the coracoid process of the scapula. Functionally, it contributes to increase posterior tipping of the scapula and reduce internal rotation of scapula during arm elevation. When this muscle undergoes adaptive shortening of the pectoralis minor, its flexibility diminishes because its overall length and the number of sarcomeres arranged in series decrease, leading to fewer actin-myosin cross-bridges available for movement. As a result, a shortened pectoralis minor muscle limits normal scapular mechanics, preventing full upward rotation, external rotation, posterior tipping and elevation of the scapula. In rounded shoulder posture pectoralis minor length test is commonly used to evaluate muscle tightness of pectoralis minor muscle. RSP occurs in up to 73% of the group of healthy participants between the ages of 20-35 years⁶.The forward head posture could cause rounded shoulder posture on the sagittal plane, disrupting the upper body ideal posture⁷. Forward head posture was found to be correlated with rounded shoulder posture prevalence is 63.9% among university students⁸.

Scapular dyskinesis may arise when factors such as muscular imbalance, weakness, restricted flexibility, or injury to bony and soft tissues disrupt the scapula’s normal function, alter its resting alignment, and impair dynamic motion.⁹ Optimal shoulder function is closely associated with proper scapular orientation and motion¹⁰.The RSP causes the scapula to exhibit an anterior tilt, downward rotation, and protraction as well as an increase in the kyphosis of upper thoracic vertebrae and the lordosis of cervical vertebrae. For rounded shoulder posture, the lateral scapular slide test (LSST) can be used to determine scapular alignment. The LSST was originally developed by Kibler to assess scapular asymmetry across different levels of muscular demand.

Postural correction exercises like shoulder shrugging, chin tucks and scapular retractions¹¹. Proprioceptive neuromuscular facilitation (PNF) is the most common exercise in the field of muscle rehabilitation¹². PNF exercises are designed to facilitate the neuromuscular response of the proprioceptors and its diagonal patterns are in line with the topographic orientation of the muscle¹³. PNF stretching techniques, used to inhibit and facilitate muscle activation and to increase the likelihood that the muscle to be lengthened remains as relaxed as possible as it is stretched. Mechanism of PNF stretching is that reflexive muscle relaxation occurs during stretch as the result of autogenic or reciprocal inhibition¹⁴.

METHOD:

Total number of 30 individuals were included in the study. They were selected according to inclusion and exclusion criteria. Participants were recruited according to inclusion criteria, which required a lateral scapular slide test (LSST) distance greater than 1.5 cm and a pectoralis minor length test (PMLT) distance greater than 2.5 cm. Students with documented scoliosis, congenital spinal defects such as Klippel-Feil or Scheuermann disease, or a history of ribcage, spine, or shoulder girdle trauma or surgery were excluded. Participants were allotted randomly in two equal number of groups: Group A -Experimental group and Group B -Control group.

Outcome measures included the LSST, which involved measuring the distance from the inferior angle of the scapula to the nearest vertebral spinous process in three positions-neutral (fig.no. -1), hands on hips at 40–45° abduction (fig.no. -2), and 90° abduction with full internal rotation (fig.no. -3), with a bilateral difference of more than 1.5 cm considered abnormal^11,17. The LSST has demonstrated excellent interrater reliability (ICC >0.9)¹⁸. The second outcome measure was the PMLT (fig.no. -4), defined as the vertical distance between the posterior surface of the shoulder peak and the supporting surface in supine lying with elbows flexed and arms by the side, with a distance greater than 2.5 cm indicating a shortened pectoralis minor and rounded shoulder posture⁶. The PMLT has shown excellent intra-rater reliability and acceptable clinical validity¹⁹. Baseline assessment was performed for both groups using LSST and PMLT, followed by reassessment after the one-week intervention to determine changes in scapular position and pectoralis minor length.

Fig. No. 1:

Fig. No. 2:

Fig. No. 3:

Fig. No. 4:

Group A (N=15) includes the proprioceptive neuromuscular facilitation stretching along with postural correction exercises. For PNF stretching participant in sitting position, therapist should place one hand posterior on the scapula and the other hand anterior on the shoulder just above the coracoid process. As the patient breathes in, tip the scapula posteriorly by pressing up and back against the coracoid process while pressing downward against the inferior angle of scapula (fig.no. -5 and fig.no. -6) and ask the participant to hold light to moderate contraction for 6 seconds, followed by an assisted stretch for 30 seconds. The participant will be relaxed for 10 seconds and followed by another 6 sec contraction and 30 sec assisted stretch repeat this procedure for 4 times with 10 seconds of relaxation time in between with postural correction exercises. This technique will be performed for 1 week^14,15,16. Group B (N=15) includes postural correction exercises like chin tucks 10 repetition, shoulder shrugging 10 repetition and scapular retractions 10 repetition. This will be performed for 1 week.^9,11

Fig. No. 5:

Fig. No. 6:

Statistical analysis:

The data presented Graph No.-1 shows that, the age of Samples varied from 19- 25 years. Graph No.-2 shows the gender distribution: Group A included 12 females and 3 males, while Group B included 11 females and 4 males.

Graph No.-1: distribution of Samples according to their Age.

Graph No. 2: Distribution of Samples according to their Gender

A total of 30 medical students were divided equally into two groups (Group A: PNF stretching with postural correction exercises and Group B: postural correction exercises only). Pre- and post-test mean values with standard deviations for pectoralis minor flexibility are presented in Table no.-1. Group A demonstrated significant reductions in mean values across LSST Neutral, LSST 45°, LSST 90°, and PMLT measures, indicating improved flexibility following intervention.

Table No. 1: Mean and Standard Deviations of Samples Medical students before and After Intervention

Parameters		Pre–test		Post-Test
Parameters		Mean	S. D	Mean	S. D
LSST Neutral Right	Group – A	3.2	±0.560	2.193	± 0.563
LSST Neutral Right	Group – B	5.866	0.655	4.86	0.766
LSST Neutral Left	Group – A	3.16	0.523	2.2	0.56
LSST Neutral Left	Group – B	5.866	0.766	4.793	0.69
LSST 45° Right	Group – A	3.3	0.565	2.29	0.564
LSST 45° Right	Group – B	5.06	0.624	4.06	0.622
LSST 45° Left	Group – A	2.34	1.084	2.32	1.078
LSST 45° Left	Group – B	5.06	0.622	4.06	0.624
LSST 90° Right	Group – A	2.83	0.308	1.82	0.32
LSST 90° Right	Group – B	4.5	0.534	3.49	0.541
LSST 90° Left	Group – A	2.83	3.09	1.82	0.302
LSST 90° Left	Group – B	4.06	0.624	4.5	0.534
PMLT Right	Group – A	4.04	0.562	3	0.233
PMLT Right	Group – B	5.9	0.689	4.9	0.686
PMLT Left	Group – A	3.88	0.242	2.84	0.223
PMLT Left	Group – B	5.66	0.523	4.66	0.519

Tables no.-2 and Tables no.-3 present the paired t-test results for Groups A and B. Both interventions produced statistically significant improvements in LSST across neutral, 45°, and 90° positions bilaterally, as well as in PMLT on both sides (all p < 0.05). Group A (PNF with postural correction exercises) showed consistent mean differences around 1.0, while Group B (postural correction exercises only) demonstrated comparable improvements, with slightly higher mean changes in certain measures (e.g., LSST 45° left). These findings indicate that both interventions were effective in correcting rounded shoulder posture among medical students.

Table No. 2: In Group A paired t-test was computed, the findings are as follows:

Group A	Mean	St. Deviation	St. Error Mean	t	Df	P-Value
Pre-test – Post-Test LSST Neutral Right	01.006	±0.258	0.006	15.012	14	0.00
Pre-test – Post-Test LSST Neutral Left	0.966	+0.129	.333	29.70	14	0.00
Pre-test – Post-test LSST 45⁰Right	1.013	+0.351	.009	11.531	14	0.00
Pre-test – Post-test LSST 45⁰Left	1.020	+0.414	.106	9.097	14	0.00
Pre-test – Post-test LSST 90⁰Right	1.11	0.832	.6971	05.664	14	0.00
Pre-test – Post-test LSST 90⁰Left	1.013	0.351	.096	08.57	14	0.00
Pre-test – Post-test PMLT Right	1.066	.378	0.0978	10.291	14	0.001
Pre-test – Post-test PMLT Left.	01.073	0.257	0.66	16.13	14	0.00

‘t’₍₁₄₎ = 1.761, P<0.05

Table No. 3: In Group B Paired t-test was computed, the findings are as follows:

Group B	Mean	St. Deviation	St. Error Mean	t	df	P-Value
Pre-test –Post-Test LSST Neutral Right	01.066	±0.258	0.056	14.002	14	0.00
Pre-test – Post-Test LSST Neutral Left	01.076	+0.0256	.0667	15.70	14	0.00
Pre-test – Post-test LSST 45⁰Right	1.006	+0.251	.067	12.531	14	0.00
Pre-test – Post-test LSST 45⁰Left	1.720	+0.256	.006	8.097	14	0.00
Pre-test – Post-test LSST 90⁰Right	1.100	0.025	.0661	12.604	14	0.00
Pre-test – Post-test LSST 90⁰Left	1.103	0.0503	.1306	03.381	14	0.00
Pre-test – Post-test PMLT Right	1.065	.0258	0.0678	09.981	14	0.001
Pre-test – Post-test PMLT Left.	01.73	0.357	0.618	11.120	14	0.00

‘t’ ₍₁₄₎ = 1.761, P<0.05

Table No.-4 shows the comparison between Group A and Group B. The combined analysis of LSST (neutral, 45°, and 90° positions on both right and left sides) and PMLT (right and left) demonstrated significant differences between Group A and Group B. Independent t-tests consistently revealed lower mean values in Group A compared to Group B across all components, with mean differences ranging from approximately 1.6 to 2.7 and p values < 0.05. These findings indicate that the addition of PNF stretching of the pectoralis minor muscle produced superior improvements in scapular positioning and muscle length compared to postural correction exercises alone, confirming the greater efficacy of the combined intervention.

Table No. 4: Comparison between Group A and Group B on all outcome measures, Independent ‘t’– test was computed, the findings are as follows.

Parameters	Mean		Mean difference	Standard Error Difference	Independent ‘t’ test	P-Value
Parameters	Group A	Group B	Mean difference	Standard Error Difference	Independent ‘t’ test	P-Value
LSST Neutral Right	2.19	4.86	2.666	0.223	11.945	0.02
LSST Neutral Left	2.2	4.79	2.5933	0.229	11.296	0.01
LSST 45° Right	2.293	4.06	1.766	0.2174	8.126	0
LSST 45° Left	2.8	4.86	1.74	0.2175	7.998	0
LSST 90° Right	1.82	3.493	1.673	0.1602	10.442	0
LSST 90° Left	1.82	3.433	1.613	0.1602	10.464	0
PMLT Right	3	4.9	1.9	0.228	8.324	0
PMLT Left	2.846	4.66	1.8133	0.1458	12.424	0

‘t’ ₍₂₈₎= 1.701, p<0.05

DISCUSSION:

The current study was designed to see the effectiveness of proprioceptive neuromuscular facilitation (PNF) stretching of the pectoralis minor muscle on rounded shoulder posture in medical students. A postural deviation increasingly prevalent due to prolonged study hours, mobile and laptop usage, and poor ergonomic habits. Rounded shoulder posture (RSP) is characterized by anterior displacement of the acromion process and scapular protraction, often resulting from muscle imbalances such as shortening of the pectoralis minor and lengthening of posterior stabilizers.

The aim of the study was to evaluate the impact of PNF stretching on improving scapular alignment and pectoralis minor flexibility, with objectives focused on assessing the effectiveness of PNF stretching of pectoralis minor muscle combined with postural correction exercises versus postural correction exercises alone, using the Lateral Scapular Slide Test (LSST) and Pectoralis Minor Length Test (PMLT) as outcome measures.

The study included 30 medical students with rounded shoulder aged 18–25 years, randomly divided into two groups: Group A and Group B. The intervention was conducted over one week, comparing two groups: Group A received PNF stretching of pectoralis minor muscle combined with postural correction exercises, while Group B received only postural correction exercises.

The PNF technique involved assisted stretching with isometric contractions and relaxation phases, targeting the pectoralis minor muscle.

Statistical analysis was performed using paired and unpaired t-tests to assess within-group and between-group differences. A significance level of p<0.05 was used to determine whether the observed changes were statistically meaningful. The results revealed that Group A showed a significant reduction in LSST and PMLT values post-intervention, with p-values well below 0.05, indicating that the improvements were not due to chance. In contrast, Group B showed only modest improvements, with some parameters approaching but not consistently reaching statistical significance.

Physiologically, the LSST measures scapular asymmetry by quantifying the distance between the inferior angle of the scapula and the vertebral midline. A reduction in this distance post-intervention reflects improved scapular retraction and stabilization. In Group A, the decrease in LSST values suggests that PNF stretching effectively addressed anterior muscle tightness, allowing the scapula to reposition more symmetrically. This supports Kibler’s findings that LSST is a reliable tool for monitoring scapular stabilizer function during rehabilitation.

The PMLT assesses the vertical distance from the posterior shoulder peak to the supporting surface in supine lying. A shorter distance post-intervention indicates increased flexibility of the pectoralis minor muscle. Group A demonstrated a statistically significant reduction in PMLT values, suggesting that PNF stretching facilitated elongation of muscle fibres through mechanisms such as autogenic and reciprocal inhibition. This allowed for improved scapular posterior tipping and reduced protraction, contributing to better postural alignment.

In contrast, Group B showed only modest improvements in both LSST and PMLT values. While postural correction exercises such as chin tucks, shoulder shrugging, and scapular retractions may enhance awareness and activation of postural muscles, they may not be sufficient to overcome the adaptive shortening of the pectoralis minor. This supports the findings of Vohra et al. (2014), who concluded that PNF stretching is more effective than static stretching in improving pectoral muscle flexibility and shoulder posture.

The results also align with studies by Nazli Busra Cigercioglu et al. (2022) and Shahnaz Hasan et al. (2023), which demonstrated that PNF training and combined muscle strengthening/stretching protocols significantly improved scapular muscle balance and pectoralis minor length. These studies reinforce the current findings, highlighting the superior efficacy of neuromuscular facilitation techniques in correcting RSP.

In summary, the physiological improvements observed through LSST and PMLT in the experimental group highlight the efficacy of PNF stretching in restoring muscular balance, enhancing scapular mechanics, and correcting rounded shoulder posture. These findings underscore the importance of integrating neuromuscular facilitation techniques into rehabilitation protocols for postural correction.

CONCLUSION:

The study concluded that proprioceptive neuromuscular facilitation (PNF) stretching of the pectoralis minor muscle, when combined with postural correction exercises, is significantly more effective in improving rounded shoulder posture among medical students than postural correction exercises alone.

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Received on 28.11.2025 Revised on 23.12.2025

Accepted on 13.01.2026 Published on 14.02.2026

Available online from February 18, 2026

Research J. Science and Tech. 2026; 18(1):1-7.

DOI: 10.52711/2349-2988.2026.00001

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