The Effect of an 8-week NASM Corrective Exercise Program on Upper Crossed Syndrome

* Corresponding Author: Mahsa Abdolahzade, MA. Address: Department of Sports Injuries and Corrective Exercise, Shafagh Institute of Higher Education, Tonekabon, Iran. Tel: +98 (911) 8837761 E-mail: mahsa.abdolahzadeh@gmail.com 1. Department of Sports Injuries and Corrective Exercise, Shafagh Institute of Higher Education, Tonekabon, Iran. 2. Department of Sports Injuries and Corrective Exercise, Faculty of Physical Education and Sport Sciences, University of Guilan, Rasht, Iran. *Mahsa Abdolahzade1 , Hassan Daneshmandi2


Introduction
uscle imbalance can affect the body's natural alignment and cause a variety of postural abnormalities [1]. Improper posture and long-term work tasks can lead to musculoskeletal disorders [2]. Early and timely identification of these postural defects and their treatment can reduce its complications and help save time and money [3]. Muscle imbalance can have serious and M known consequences in the body [1]. Upper Crossed Syndrome (UCS) occurs in the neck and shoulder girdle [4]. This syndrome is a type of musculoskeletal system involvement that results in shortening of the upper posterior and anterior muscles in the neck, which are tonic muscles (e.g. pectoralis major muscle, upper trapezius, levator scapula, sternocleidomastoid) and the anterior deep muscles of the neck and posterior shoulder girdle, which are mainly phasic (e.g. Rhomboid major, middle and lower trapezius muscles, serratus anterior muscle, and deep neck flexors) are inhibited and weakened. Postural changes seen in UCS include forward head, rounded shoulders, and thoracic kyphosis [5].
There have been several reports of osteoarthritis of the temporomandibular joint due to forward head and mechanical pain in the head [4]. There are also some reports of radicular pain in the arms and hands due to osteoarthritis of the neck due to UCS [2]. Such adverse secondary changes resulting from this syndrome are also present in people with thoracic kyphosis in the glenohumeral joint [4,11].

Methods
In this study, 30 female students [15] with forward head posture > 46 degrees [16], forward shoulder posture > 52 degrees [16] and thoracic kyphosis > 42 degrees [17] were selected as samples using purposive sampling method and randomly divided into groups of control and intervention. Participants in the intervention group received 8 weeks of corrective exercise, 3 sessions per week, each for 30-70 min. National Academy of Sports Medicine (NASM) principles were used to develop the training program. The program follows certain training protocols in designing and implementing corrective exercises. It consists of four stages of inhibition, stretch, activation and coherence [9].
The head-forward and shoulder-forward angles were measured using side photography [19], the kyphosis angle was measured using a flexible ruler (r=0.093) [20] before and after intervention. The type of movements was determined by referring to specialists and resources of movement therapy and then finalized and implemented through a pilot study on some study samples [21]. The Shapiro-Wilk test was used to measure the normal distribution of data. In order to analyze the data obtained from pre-test and posttest phases, pair t test was used, and ANOVA test was used to compare the study changes. Table 1 presents the characteristics of participants and test results. Due to the long and incorrect sitting position and repetitive use of the upper limbs in students, there is a possibility that the balance of the muscles of the upper extremity is disturbed. Since muscle imbalances in the upper quarter of the body increase the risk of UCS, and UCS is associated with three postures of head forward, rounded shoulder and thoracic kyphosis, the exercises in this study were comprehensively and simultaneously based on these three abnormalities. The people with UCS need to pay special attention to the issue of muscle balance while sitting, in addition to correcting the posture of the head, neck and back. The results showed the positive impact of exercise based on NASM principles on muscle balance and correcting head forward, rounded shoulder and thoracic kyphosis postures.

Discussion
UCS is commonly seen in people who sit for long periods of time or in people who apply frequent overload patterns to upper limbs [8,9]. Corrective exercises have been reported to be one of the most effective ways to restore performance [23]. Eight weeks of corrective exercises regulates muscle activity and musculoskeletal disorders in the upper body [24]. In this study, the four-step NASM-based corrective protocol was focused on all three abnormalities caused by UCS at the same time, and is consistent with the Janda approach and the Bruegger's exercise [8]. Researchers have shown that strength training affects the length of the muscle tendon, displacing different parts of the skeleton and stabilizing the ligaments. On the other hand stretching exercises act as coordinator of agonist and antagonist muscles. Thus, such exercises increase the length of the muscles on the concave side, the muscle power and strength on the convex side, and thus reduce the rate of postural abnormalities [37]. We attempted to apply the exercise program more in a closed chain of motion and more in a weight-bearing position to simulate real-life activities [36].

Conclusion
In general, it seems that the use of corrective exercises can lead to improvements in flexibility and strength following

Funding
This study was extracted from the master thesis of first author approved by Department of Sport Injuries and corrective exercises, Shafagh Institute of Higher Education, Tonekabon, Iran.

Conflicts of interest
The author declared no conflict of interest