Does corrective exercises influence the performance, posture, range of motion and shoulder pain of swimmers with upper crossed syndrome? randomized clinical trial

Abstract

Background

This study sought to evaluate the effect of corrective exercises on forward head angle, forward shoulder angle, thoracic kyphosis degree, range of motion, and shoulder pain in elite front crawl swimmers presenting with upper crossed syndrome.

Methodology

In this quasi-experimental study, 30 professional male swimmers aged 20 to 40 years (mean ± SD age: intervention group = 28.85 ± 6.49, control group = 27.66 ± 6.19) were randomly assigned to experimental (n = 15) and control (n = 15) groups. The experimental group underwent an eight-week corrective exercise program alongside their regular training. Assessment measures included photogrammetric analysis for forward head and shoulder posture angles, flexible ruler for thoracic kyphosis quantification, visual analog scale for pain evaluation, handheld chronometry for record assessment, and goniometer goniometric measurement for range of motion evaluation. After confirming normal data distribution using the Shapiro-Wilk test, Mixed ANOVA was used to assess the effects of the intervention at a significance level of 0.05.

Results

The analysis revealed significant improvements in forward head posture (P <.001), rounded shoulders (P <.001), thoracic kyphosis (P <.001), shoulder range of motion (P <.001), and pain levels (P <.001) in the intervention group. However, no significant differences were found in performance measures such as swim record (P >.386) and stroke rate (P >.630).

Conclusion

Corrective exercises were effective in improving postural alignment, range of motion, and shoulder pain symptomatology, but did not significantly affect swimming performance. These findings suggest such exercises are more effective for addressing postural and clinical concerns. Further research using longer or varied protocols is recommended to explore potential performance outcomes.

Trial registration

Clinical trial code: IRCT20240306061185N1, registered at the Iranian Registry of Clinical Trials on 08/03/2024.

Introduction

Swimming is globally popular sport [1], accessible to everyone regardless of age or gender [2] that requires a wide range of shoulder movements involving both clockwise and counterclockwise rotations with different degrees of internal and external rotation [3]. According to recent studies, injury rates among elite swimmers are 4 injuries per 1,000 training hours for men and 3.78 for women [4]. Shoulder injuries account for the largest proportion (27%) of all swimming-related injuries, with most injuries attributed to overuse mechanisms (42.6%) [5].

In swimming, approximately 90% of forward propulsion force is generated by the upper limbs. this explains the prevalence of shoulder pain and injuries. In fact, shoulder pain is the most common musculoskeletal complaint among swimmers [6], with reported prevalence rates ranging from 40 to 91% [7]. it leads to muscle inhibition, reduced strength, joint stability, and an increased risk of subsequent shoulder injuries [4].

Prolonged poor postures and repetitive activities can lead to spinal abnormalities, affecting nearby areas in a chain reaction. Over time, these factors can cause changes in tissue characteristics and lead to postural disorders [8]. One common issue is Upper Crossed Syndrome (UCS), as a muscular imbalance introduced by Janda that affects the posture of the neck, thoracic spine, and shoulder girdle [9]. In front crawl Swimmers, the tendency toward excessive shoulder adduction and internal rotation movements increases the likelihood of developing UCS or related characteristics [10]. this can lead to forward head posture, rounded shoulders, and increased thoracic kyphosis, which can affect the subacromial space and glenohumeral range of motion [10]. These physical changes are believed to help swimmers by allowing their upper limbs to adjust to training demands. However, while this idea is widely accepted based on experience, it has not been scientifically proven in research [2].

Currently, the minimal time differences between finalists and winners in swimming competitions have driven athletes, coaches, and sports specialists to seek for improvements in " marginal performance differences " [11]. Effective athlete training now depends on close monitoring of movement patterns and correct stroke identification [12], which ultimately leads to technique refinement [11]. Swimming speed - a product of stroke length - has been widely used by coaches and swimmers to monitor swimming performance. Manipulating stroke length and rate affects the maximum achievable swimming speed [13]. While many studies have addressed the reduction and improvement of swimmers’ shoulder pain, there is limited research on how corrective exercise protocols in swimmers can improve posture. Moreover, it remains unclear whether improving upper body posture can positively impact swimming performance and manage pain in the shoulder. Therefore, this study aims to investigate whether an eight-week corrective exercises in swimmers can improve posture, shoulder pain, and range of emotion, while enhancing performance in terms of swimming speed and technique in elite swimmers with UCS and upper quarter alignment. If corrective exercises help manage UCS, they may also reduce pain and injury risk, potentially contributing to better performance outcomes in swimmers.

Methodology

Study design and participants

A parallel-group randomized controlled trial, registered under code IRCT20240306061185N1 at the Iranian Registry of Clinical Trials, employed a quasi-experimental design with pre-test and post-test measurements for both experimental and control groups. This entire procedure was conducted according to the CONSORT guidelines to ensure transparent and standardized reporting of the trial (Fig. 1) [14]. The study was cross-sectional in terms of duration and applied in terms of results utilization. The statistical population included professional male swimmers aged 20–40 years with a minimum of 3 years of athletic experience. All participants in this study had USC and mild to moderate shoulder pain based on self-report using the Visual Analogue Scale (VAS), with pain levels ranging from 1 to 7. Participants were selected through convenience sampling. After explaining all procedures and collecting demographic data, informed consent was obtained. Participants were randomly divided into experimental (n = 14) and control (n = 15) groups. One participant from the experimental group withdrew, leaving 14 in that group. All swimmers regularly trained three days per week in afternoon sessions. The experimental group performed corrective exercises three days per week for eight weeks in addition to their regular training.

Fig. 1.

Study fowchart

To distinguish affected individuals, quantitative assessments of head, shoulder, and thoracic arch were performed and those with criteria related to upper cross syndrome were included in the experimental group [15]. Inclusion criteria comprised: forward head angle > 45° [16]; forward shoulder angle > 52° [15, 16]; kyphosis > 40° [16]; self-reported shoulder pain (VAS 1–7); minimum of 3 regular training sessions per week; no history of spinal or upper limb surgery; and at least 3 years of front crawl swimming experience. Exclusion criteria included: occurrence of any serious injury during the study, absence from post-test assessment, missing three consecutive training sessions during the intervention.

Study outcomes and assessments

Photogrammetry was used to measure forward shoulder angle (reliability = 0.91) [17] and forward head angle (reliability = 0.88) [17]. Participants were asked to maintain a comfortable and natural posture, as if they were not being observed. They were asked to take three deep breaths and stand comfortably. A lateral photograph was then taken from a distance of 265 cm at shoulder height. The angles of the forward head posture and forward shoulder posture were calculated using AutoCAD 2018 software [18].

To assess kyphosis, a flexible ruler was used. Each participant was asked to stand naturally without clothing in front of the examiner. The examiner then marked the second (T2) and twelfth (T12) thoracic vertebrae with markers [19]. All measurements were taken in a quiet standing position, with participants instructed to distribute their weight equally on both feet and look straight ahead [3]. The flexible ruler was then carefully molded along the contour of the participant’s spine to capture its shape. To calculate the thoracic curve angle from the obtained shape, points T2 and T12 were connected with a straight line, and another line was drawn from the deepest point of the curve to this line. These lines are labeled as L and H, respectively. Their lengths were measured with a millimeter ruler, and entered into the formula 4arctg2H/L to determind the angle.

To measure swimmers’ shoulder pain, participants were asked to respond VAS, which is a metric with gradations from zero to 10 indicating pain levels. A score of 1–3 indicates mild pain, 4–7 indicates moderate pain, and 8–10 indicates severe pain [20]. the pain level was assessed under the supervision of an orthopedic specialist based on the participant’s self-report.

Active shoulder range of motion was measured for each participant using a universal manual goniometer [21]. The range of motion was measured for flexion, extension, internal rotation, and external rotation.

Shoulder range of motion was measured using a goniometer. For flexion, participants were lay supine while goniometer’s center was placed 2.5 cm lateral to the acromion end. The stationary arm aligned with the trunk’s midline, and the moving arm with the lateral midline of the humerus, aligned with the lateral epicondyle. The participant raised their arm upward the humerus from the examination table as far as possible (until discomfort) [22].

For extension, participants lay prone. The goniometer’s center was placed on the humeral head at the glenohumeral joint, the stationary arm aligned with the axillary midline and the moving arm with the lateral epicondyle of the humerus. Participants were then asked to move their hand upward as far as possible [22].

To measure internal rotation, participants lay supine with their shoulder abducted at 90° abduction and elbow fixed at 90°. The goniometer’s center was placed on the olecranon process, with its longitudinal axis parallel to the ulna’s longitudinal axis [22].

For external rotation, participants remained supine with their shoulder in 90° abduction and forearm perpendicular to the table. The goniometer’s stationary arm was aligned parallel to the forearm with its center on the olecranon process, and the moving arm was aligned with the radial styloid process [22]. Participants rotated their arm outward to the limit of their pain-free range. Scapular elevation was not permitted during any of the measurement [23].

To record the swimmer’s 50-meter time (in a standard 25-meter competition pool), the examiner walked alongside the pool while measuring the duration using a handheld stopwatch. To eliminate variables such as flight time, platform departure time, and other kinematic variables affecting swimming performance, all records began with an in-water start. The front crawl stroke frequency was calculated using the formula: (100 * [number of strokes in 50 m/swimming time in seconds]) [24]. In this context, one stroke in front crawl refers to the cycle from the moment one hand enters the water until the same hand enters the water again.

The corrective exercise protocol was designed based on previous studies focusing on swimmers’ shoulder pain, postural deviations, and upper crossed syndrome. The final training program emphasized flexibility and muscle strengthening according to references [7, 19, 25] (Table 1). For the experimental group, this training protocol consisted of three sessions per week over eight weeks, with each session lasting 30–40 min. the exercises were conducted at the gym of the swimming pool under the supervion of a physical therapist. These land-based exercises were performed before the team’s regular daily training. The swimmer-specific corrective exercises, as detailed in Table 1, included specialized movements that adhered to the principle of training specificity while following standard exercise design principles. The intensity progressed throughout the eight weeks through increases in repetitions, duration, and the number of movements. In contrast, the control group continued their regular swimming training without receiving any corrective exercise intervention.

Table 1.

Corrective exercise protocol

Exercise	Muscles Activation	1–2 weeks		3–4 weeks		Notes
		Repetitions	Duration	Repetitions	Duration
Chin tuck	Upper thoracic extensor, neck muscles	4*15s	--------	4*20s	--------	Gently tuck the chin towards the chest while keeping the neck straight. Hold briefly before releasing.
Latissimus dorsi -stretch	Latissimus dorsi, teres major, pectoralis major	4*15s	--------	4*20s	--------	Extend one arm overhead and lean to the opposite side to stretch the latissimus dorsi.
Scalene-stretch	anterior, middle, and posterior scalenes	--------	--------	4*20s	--------	Tilt the head to one side, gently pulling it towards the shoulder to stretch the scalene muscles.
Pectoral-stretch	Deltoids, Rotator cuff, Trapezius, Latissimus Dorsi, Levlator Scapulae	4*15s	--------	4*20s	--------	Stand near a wall or doorway, place the hands on the surface, and gently push forward to stretch the chest.
Scapular-squeeze	upper, middle, and lower trapezius, Rhomboids	4*15s	--------	4*20s	--------	Pull the shoulder blades together while maintaining a straight posture. Hold briefly before releasing.
Trunk rotation	latissimus dorsi,	--------	4*8	--------	4*10	Sit upright, rotate the torso to one side, and hold briefly before returning to the center.
External rotation	teres minor, infraspinatus deltoid, trapezius	--------	4*8	--------	4*10	Hold a resistance band, rotate the arm outward while keeping the elbow at 90 degrees.
Scapular retraction	serratus anterior, pectoralis major, pectoralis minor	--------	4*8	--------	4*10	Pull the shoulder blades back and down while keeping the arms relaxed. Hold before releasing.
Y-raise	Deltoids, Trapezius, rhomboids, biceps	--------	4*8	--------	4*10	Lift the arms overhead in a “Y” shape while keeping the posture straight.
Exercise	Muscles Activation	5–6 weeks		7–8 weeks		Notes
		Repetitions	Duration	Repetitions	Duration
Dynamic latissimus dorsi stretch	Latissimus dorsi, teres major, pectoralis major	--------	4*10	--------	4*12	Perform a latissimus dorsi stretch while actively moving through the range of motion.
Dynamic W-stretch	Neck, Upper-, Mid-, and Lower Trapezius	--------	4*10	--------	4*12	Raise both arms in a “W” shape, then actively squeeze the shoulder blades together while lowering and raising the arms slightly.
Push-up trunk rotation	anterior deltoid, pectoralis major, Trapezius	--------	4*10	--------	4*12	Perform a push-up, then rotate the torso to one side, raising one arm towards the ceiling.
Pectoral dynamic Stretch	Pectorals, Upper-, Mid-, and Lower Trapezius	--------	--------	--------	4*12	Stand near a wall or doorway, place your hands on the surface, and move forward and backward dynamically to stretch the chest muscles.
Superman	upper back, shoulders, glutes	--------	4*10	--------	4*12	Lie face-down, lift both arms and legs off the ground simultaneously.
Pelvic tilt	Multifidus, abdominis, rhomboids	--------	4*10	--------	4*12	Lie on the back, tilt the pelvis forward and backward to engage core muscles.
Wall push up	Deltoids, serratus anterior, mid trapezius	--------	4*10	--------	4*12	Perform a push-up against a wall while keeping a controlled motion.
Bird dog	Erector spinae, latissimus dorsi, trapezius, Rotator cuff, teres minor, deltoids serratus anterior,	--------	4*10	--------	4*12	On hands and knees, extend one arm and the opposite leg simultaneously while maintaining balance.
Head lift with neck curl	Ternocleidomastoid, neck	--------	4*10	--------	4*12	Lie on the back, lift the head slightly while engaging the neck muscles.
Scalene-stretch	anterior, middle, and posterior scalenes	4*25s		4*30s		Tilt your head to one side while gently pulling it toward your shoulder. Keep the opposite arm relaxed or behind your back to intensify the stretch.
Sleeper stretch	teres minor, infraspinatus, rotator cuff	4*25s		4*30s		Lie on your side with the bottom arm extended at a 90-degree angle. Use the top hand to gently press the bottom hand downward to stretch the rotator cuff muscles.
Levator Scapulae and Trapezius Stretch	levator scapula, upper trapezius, neck	4*25s		4*30s		Tilt the head slightly downward and to one side while gently pulling the head towards the shoulder.

Randomization

The computer-generated block randomization (1:1:1 ratio) was generated using the website the website https://www.sealedenvelope.com. The main reseracher performed the enrollment, generated the random allocation sequence, and assigned the subjects to the groups To keep the assignments hidden, each group name was placed in a sealed, numbered, and opaque envelope. These envelopes were opened only after each participant joined the study. A university assistant professor supervised all procedures, including the sequence generation process and allocation concealment mechanism, to ensure that the assignment were done fairly and could not be predicted.

Sample size and statistical analysis

The G × Power software (Version 3.0.10, Germany) was used to calculate the sample size regarding the efect size reported for the corrective exercises compared with the control group without any intervention in a similar study, totally (n = 30). Distribution normality was evaluated via Shapiro-Wilk analysis. For data with normal distribution, parametric tests were used. Repeated measures ANOVA was employed for group comparisons, utilizing SPSS-27 statistical software. A significance level of P <.05 was considered for all analyses.

Results

In this study, the intervention and control groups had similar demographics, with mean ages of 28.86 and 27.67 years, and mean weights of 80.07 and 81.60 kg, respectively. This indicates a homogeneous population. One participant from the intervention group discontinued the corrective exercise protocol and was excluded from the study. The final participant count totaled 29, 14 in the intervention group and 15 in the control group. Mean scores for all variables in both groups at pre- and post-test stages are presented in Table 1, and Table 2 shows the Mixed ANOVA statistical analysis results for determining the training intervention effects across all variables.

Table 2.

Study variable data (means and standard deviations) for experimental and control groups

Variable		Mean	Lower	Upper	F	P Value	Eta
Kyphosis	degree	-3.21	-4.11	-2.31	31.23	< 0.001	0.536
Forward head posture Angle	Angle	-3.54	-4.01	-3.07	109.35	< 0.001	0.802
Round shoulder posture Angle	Angle	-2.76	-3.36	-2.17	37.31	< 0.001	0.580
Flexion	degree	9.07	7.73	10.40	115.69	< 0.001	0.811
Extension	degree	6.21	5.43	6.99	164.57	< 0.001	0.859
internal rotation	degree	7.78	6.32	9.25	58.36	< 0.001	0.684
external rotation	degree	6.35	5.69	7.01	194.45	< 0.001	0.878
Record	Second	-2.31	-3.84	− 0.78	0.77	0.386	0.028
Stroke	Count	0.79	-0.21	1.61	0.23	0.630	0.009
Pain	VAS	-2.85	-3.28	-2.42	91.45	< 0.001	0.772

*The 95% Confidence Interval (CI)

The Mixed ANOVA results revealed significant main effects between pre-test and post-test measurements (P <.05). At a 95% confidence level, there were significant differences between groups in pain reduction, kyphosis degree, forward head angle, and forward shoulder angle (Table 3), indicating improved body alignment following the eight-week corrective exercise program. Significant improvement were found in range of motion for flexion, extension, internal rotation, and external rotation. However, there were no significant differences between groups in performance measures, including swim time and stroke frequency (P >.05, Table 3).

Table 3.

Pairwise comparisons from repeated-measures analysis of variance for study variables examining

		Control		Experimental
		Pre- test	Pos- test	Pre- test	Pos- test
Variable		Mean ± Standard devition	Mean ± Standard devition	Mean ± Standard devition	Mean ± Standard devition
Kyphosis	degree	46.55 ± 5.64	46.76 ± 4.51	47.48 ± 7.06	44.26 ± 7.19
Forward head posture	Angle	48.83 ± 1.89	48.64 ± 2.16	48.79 ± 1.99	45.24 ± 2.01
Round shoulder posture Angle	Angle	54.96 ± 1.77	54.65 ± 1.65	54.97 ± 1.57	52.21 ± 1.39
Flexion	degree	159.93 ± 3.63	159.26 ± 3.17	158.64 ± 3.89	167.71 ± 2.72
Extension	degree	28.8 ± 4.64	28.26 ± 4.16	30.28 ± 2.46	36.5 ± 2.37
internal rotation	degree	51.93 ± 8.88	52.13 ± 7.43	50.64 ± 6.85	58.42 ± 6.39
external rotation	degree	71.13 ± 2.87	71.26 ± 2.34	72.07 ± 3.47	78.42 ± 3.63
Record	Second	41.59 ± 6.73	40.18 ± 5.58	39.57 ± 7.03	37.25 ± 6.42
Stroke	Count	24.93 ± 2.45	25.45 ± 2.79	26.57 ± 2.45	27.37 ± 2.94
Pain	VAS	3.73 ± 1.48	3.66 ± 1.17	3.64 ± 1.59	0.78 ± 1.12

In summary, the intervention group showed improvements in all dependent variables related to posture, pain, and range of motion, but not in performance-related measures.

Discussion

The aim of this study was to investigate the effects of an eight-week corrective exercise program on performance, postural alignment, range of motion, and shoulder pain in professional swimmers. The findings indicated that the intervention improved the alignment of the head, neck, shoulders, and thoracic spine, which aligns with the results of studies by Lynch et al. [7], Babu et al. [3], and Hibberd et al. [2]. Based on these findings, our study suggests that implementing a corrective exercise program for swimmers with UCS can have a significant impact on improving postural alignment, reducing shoulder pain, and improving range of motion.

The results also showed that corrective exercises may be fairly effective in addressing UCS. Improving postural alignment can reduce the risk of future injuries in athletes. The findings suggest that exercises aimed at reducing muscle tightness in shortened muscles and strengthening weakened ones can serve as a simple and cost-effective strategy for correcting postural deviations. Previous studies support the results regarding reductions in forward head angle, rounded shoulders, and thoracic kyphosis through stretching and strengthening exercises [2, 26]. Postural correction is particularly important for individuals with UCS, as this condition can contribute to musculoskeletal injuries and movement dysfunction [27]. Repeated mechanical stress on the neural, muscular, and joint tissues of the neck and shoulders may increase tissue sensitivity and negatively affect central nervous system tolerance, leading to pain [28]. Sahrmann observed a significant relationship between kyphosis, forward head posture, and subacromial syndrome, noting that increased kyphosis can lead to scapular downward rotation and greater protraction, which increases pressure in the subacromial space and surrounding structures such as the bursa and rotator cuff tendons. Since forward head posture is associated with increased thoracic kyphosis and rounded shoulders, these postural patterns may result in increased scapular elevation, protraction, downward rotation, and anterior tilting [29].

It is important for individuals with Upper Crossed Syndrome (UCS) to correct their posture, as this condition may contribute to various musculoskeletal injuries and motor control issues [27]. Postural changes in one area of the body can affect adjacent segments in a chain reaction. For example, forward head posture is often accompanied by increased thoracic kyphosis, scapular protraction, and downward rotation, leading to impaired scapular stability and function. Therefore, individuals with UCS require targeted strategies to correct movement patterns [30]. This process suggests a possible relationship between improving forward head posture, rounded shoulders, and reducing shoulder pain [31]. Our findings showed significant effects on forward head angle, rounded shoulder posture, and thoracic kyphosis. Since altered scapular resting position may be associated with abnormal cervical and thoracic spinal alignment, forward head posture can contribute to rounded shoulders, which in turn may increase thoracic kyphosis [32]. The corrective exercise program included stretching and flexibility exercises focused on lengthening the shortened muscles typically affected by UCS—such as the upper trapezius, levator scapulae, sternocleidomastoid, and the pectoralis major and minor. These exercises likely helped increase the length of shortened upper posterior muscles and strengthen the anterior neck muscles, which may have contributed to correcting the forward head posture [33].

Swimmers may experience shoulder pain and functional limitations due to factors such as muscular imbalances and poor posture [7]. In our study, shoulder pain was identified as a major risk factor among swimmers, consistent with findings from Scott [6], Walker [34], and Rinonapoli et al. [35]. Competitive swimmers are at higher risk of developing shoulder pain, which can cause discomfort during swimming and daily activities. Risk factors include swim volume, training methods, and individual physical characteristics. Frequent overhead use of the upper limbs has also been recognized as a key contributor to shoulder pain, making it unsurprising that athletes with higher training loads report greater pain and disability [36]. There is a significant relationship between poor posture and shoulder pain. Harrington et al. reported that reduced pectoralis minor muscle length is associated with shoulder pain and dysfunction in swimmers [37]. Although repetitive overhead motion is believed to be the primary cause of swimmer’s shoulder, postural abnormalities are considered an intrinsic risk factor that can trigger shoulder pain [38]. In addition, functional deficits have been shown to play an important role in the high prevalence of shoulder pain in this population [39]. In thus study, participants had not previously engaged in any corrective exercise programs, which may explain the presence of shoulder pain before the intervention. However, after implementing the corrective training program, A clear reduction in pain frequency was observed among the intervention group, while the control group showed little to no change. This reduction in pain was significantly associated with improvements in postural variables and shoulder range of motion. These findings suggest that achieving better postural alignment may indirectly reduce the risk of swimmer’s shoulder and serve as a preventive strategy.

Several studies have investigated the relationship between glenohumeral (GH) joint flexibility and shoulder pain in swimmers. Most have reported no significant association between shoulder pain and shoulder joint flexibility [37], which contrasts with the findings of the present study. This discrepancy may be explained by the possibility that corrective exercises helped strengthen shoulder stabilizing muscles and reduced joint restrictions, thereby improving range of motion. Postural abnormalities such as forward head posture and hyperkyphosis can also alter GH joint mobility and cause muscular imbalances in the neck and shoulders [8]. Previous studies have suggested a link between forward head posture, spinal deformities, back muscle strength, and shoulder range of motion. Rehabilitation research further indicates that postural abnormalities like hyperkyphosis and forward head posture can disrupt scapular kinematics and restrict cervical and shoulder joint mobility [40]. In the current study, the swimmers exhibited signs of USC, which may significantly affect GH joint mobility. This syndrome is often associated with muscular imbalances, increased tension in the upper neck and shoulder muscles, and restricted shoulder motion. Research shows that such postural issues can interfere with movement patterns, limit range of motion, and increase the risk of shoulder injuries [41].

Although corrective exercises have been used in previous studies, their effect on performance remains unclear. Regarding stroke rate and swim time, statistical analysis in this study showed no significant pre- to post-test differences in these variables. In short-distance swimming (e.g., 50 m), athletes already maintain high stroke rates, and the brief duration of the event may not allow enough time for improvements in stroke mechanics. Short-distance swim performance is also heavily influenced by turn times and wall push-off force [42].

There is a lack of studies specifically examining the effect of training interventions on swimmer performance. Most existing research focuses on dryland-based strength and core stability training, with inconsistent findings on performance outcomes. The inconsistencies between our findings and those of Weston et al. [43] may be due to differences in the type, intensity, equipment used, and specificity of the corrective training protocols.

Limitations

This study had several limitations, including a relatively small sample size, the inability to control participants’ daily activities and rest routines, and the fact that only short-term effects of the intervention were assessed. It remains unclear whether the observed effects persist beyond the post-test period. Future research should evaluate the long-term effects of corrective exercise programs on posture and shoulder pain in swimmers. It is also recommended that the corrective exercise protocol used in this study be implemented over a longer period. Additionally, future studies could compare the performance of swimmers with Upper Crossed Syndrome to that of healthy swimmers with similar skill levels.

Conclusion

The results of this study demonstrated that corrective exercises can effectively improve body alignment, range of motion, and shoulder pain in swimmers. However, these exercises did not have a significant impact on their performance.

Based on the findings and the effects of these exercises on swimmers’ body alignment, range of motion, and shoulder pain, it is recommended that future researchers investigate the impact of these exercises over longer durations and across different groups of swimmers, including adolescents and female swimmers. Additionally, researchers should examine the lasting effects of these exercises and, when possible, measure the strength of internal and external rotators and scapular dyskinesia.

Hossein Rezaei

Dr. Mahdi Gheitasi is an Associate Professor at Shahid Beheshti University with expertise in sports medicine and exercise science. Hossein Rezaei is a Master’s student of corrective exercises and sport injury. Seyed Mohammad Hosseini is an Assistant Professor at Shahid Beheshti University with expertise in sports medicine and exercise science.

Author contributions

M.G. (Mahdi Gheitasi) conceptualized the study and designed the methodology. H.R. (Hossein Rezaei) collected the data and performed the analysis. S.M.H. (Seyed Mohammad Hosseini) supervised the project and reviewed the manuscript. M.G. and H.R. wrote the main manuscript text. All authors reviewed and approved the final manuscript.

Funding

Not applicable.

Data availability

The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This study was approved by the Ethics Committee of the Research Institute of Physical Education and Sports Sciences of Iran (Code: IR.SSRC.REC.1402.294). All participants provided written informed consent to participate in the study. We certify that the study was performed in accordance with the 1964 Declaration of Helsinki and later amendments. The research’s informed consent document clearly communicates the study’s purpose, procedures, risks, benefits, and rights to participants. Participants are informed that data will remain confidential, and their participation is voluntary.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.