The effectiveness of a comprehensive corrective exercises program and subsequent detraining on alignment, muscle activation, and movement pattern in men with upper crossed syndrome: protocol for a parallel-group randomized controlled trial

Most people will see a medical practitioner or another health care provider at least once in their lifetime because of neck, shoulder and back pain [1, 2]. At a societal level, these pains are also responsible for substantial costs, including healthcare expenditure, disability insurance, and work absenteeism [3]. Previous studies showed that these pains might be associated with abnormal alignments [4, 5]. One of these malalignments is the upper crossed syndrome (UCS), which was defined as a muscular imbalance pattern by Vladimir Janda MD (1923–2002) [6]. UCS refers to specific altered muscle activation and movement patterns along with some postural deviations [7]. Alterations in muscle activation include overactivity of the upper trapezius, levator scapula, and pectorals muscles and underactivity of the deep cervical flexors, middle and lower trapezius, and serratus anterior [8]. Due to kinetic and muscular chains, there are altered scapular movement patterns (scapular dyskinesis) and specific postural changes, including forward head and shoulder posture and increased thoracic kyphosis [7, 9]. These changes can lead to reduction in the stability of the glenohumeral joint and to various musculoskeletal symptoms in the head, neck, and shoulder [7, 8, 10].

Over recent decades, therapists have been seeking to design appropriate exercises to correct musculoskeletal malalignments mainly through structural and functional approaches [11‐13]. In the traditional structural approach, the changes observed in malalignments such as in UCS are attributed to biomechanics and are presumed to lead to adjustments in the length and strength of local muscles [11, 14]. This may account for the stretching of short muscles and strengthening of weakened muscles at the site of the problem in the correction phase, while ignoring other related malalignments [14]. Interestingly, despite the popularity of this method, very little research has been conducted based on this theory [15]. Furthermore, some review studies have questioned the effectiveness of strengthening and stretching exercises to improve postural disorders [16, 17].

In contrast, the functional (neurological) approach to musculoskeletal problems is based on the interaction of the central and peripheral nervous systems, and the involvement of the muscular and skeletal structures in producing and controlling motion [6, 18, 19]. In this functional approach, the musculoskeletal problems are attributed to the role of muscles in motor function; furthermore, changes in the alignment result not only from changes in muscle length and strength but also from more important changes in muscle neuromuscular factors, such as muscle recruitments [13, 20]. In fact, the motor control unit may change the muscle activation strategy for temporary stabilization due to the presence of dysfunction. These changes in motor recruitment will alter the muscular balance, movement patterns, and eventually the motor program [12]. Similarly, Hodges et al. noted that motor control interventions require tailoring to each individual’s posture, muscle activation, and movement pattern [21]. However, this theory has not been tested in practice for the prevention and treatment of musculoskeletal malalignments.

Hence, for the assessment of UCS, the alignment and its side effects are often evaluated, such as increase in thoracic kyphosis or forward head angles, while less attention has been paid to the keystone, i.e., the scapulae, and the relevant altered muscle activation and movement patterns [22]. In this regard, many researchers and therapists have only evaluated one of the affected regions, such as head, shoulders, or spine, separately and reported a degree of postural deviation regardless of other relevant malalignments and patterns of the muscle activation and related movement patterns, such as scapulohumeral rhythm or neck flexion [23‐25]. In addition, the design and implementation of the training protocol are based on the traditional structural approach, in which stretching exercises for short muscles and strengthening exercises for weak muscles are prescribed at the site of malalignment [22, 24], while the neuromuscular factors and related movement patterns may not be considered. To the best of our knowledge, no studies identifying and correcting UCS have considered the three components of alignment, movement pattern, and muscle activity in both assessment and correction processes.

We propose to evaluate the effectiveness of a randomized controlled trial of a CCEP in a group of men aged 18 to 28 years with UCS in terms of their alignment, selected muscle activation, and relevant movement patterns.

Clinicians believe that it is important to quantify head, shoulder, scapulae, and spinal posture behavior as they influence and are influenced by many biomechanical, motor control, and performance variables [43]. It has been assumed that exercise can correct postural malalignment, but an earlier review found little evidence to support this assumption [17]. Moreover, despite the widespread inclusion of postural correction in exercise interventions, there are limited empirical data to support its effectiveness and little is known about the most effective exercise interventions [24]. As already mentioned, it seems the most important reason is the adherence to the traditional structural approach in the previous studies. We want to conduct a randomized controlled trial based on the comprehensive approach which is adequately powered and utilizes validated outcome measurements of UCS to investigate the effects of the CCEP on both our primary and secondary outcomes. If the CCEP results in changing the alignment, muscle activation, and movement pattern, or all three, we will examine the pathways of change to determine whether changes in the alignment, muscle activation, or movement pattern can account for the change in the UCS symptoms. Furthermore, if we find out that the CCEP can improve a postural malalignment like in UCS, this evidence could enable practitioners to recommend early intervention for UCS to prevent or delay UCS-associated consequences. Therefore, various experts in the field of corrective exercises and physical therapy, equipped with the knowledge on these changes, can identify people with UCS and also adopt appropriate therapeutic strategies to correct it and prevent the occurrence of secondary consequences.

Our study has some limitations including the recruitment of only men 18 to 28 years of age. Therefore, the results of this study will not be generalizable to all people (e.g., women or men aged ≥ 28 years) with UCS. Another limitation is that this study is not a double-blind design since it is not possible, as is the case with most exercise trials.

The results of our study will be presented at scientific conferences and published in academic journals to ensure that our study will inform therapists in practice and prove beneficial to patient care. Our goal is to conduct a clinical trial that will provide therapists with evidence of the efficacy of the CCEP on the keystone and the side effects of UCS. Previous trials have often used only assessment of the alignment to investigate the improvement of a malalignment. However, we are focusing on alignment, muscle activation, and movement pattern simultaneously based on the comprehensive approach. Therefore, if our exercise intervention proves successful, our approach to improving UCS could represent a fundamental paradigm shift in exercise intervention strategies to improve postural malalignments and their consequences. Results from our trial may provide new insights into the effects of exercise not only on alignment but also on muscle activation and movement pattern, which are important outcomes for people with postural malalignments and, if successful, it could assist practitioners in individualized clinical decision-making. However, our results may have a limited transferability to all people and thus may be valid only for men.