Activity Of Upper Trapezius Research Articles

Electromyographic comparison of exercises for scapulothoracic muscle activation in men with upper crossed syndrome: A cross-sectional study

ObjectiveThis study aimed to determine the optimal exercise for improving Upper Crossed Syndrome (UCS) using electromyographic (EMG) activity of upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA) during ten exercises. MethodA cross-sectional study involved 30 male students (mean age: 25.3 ± 2.5 years; height: 176.8 ± 7.2 cm; weight: 77.7 ± 2.5 kg; BMI: 23.8 ± 0.72 kg/m2) with UCS. Participants were selected based on postural assessments (forward head posture ≥44°, rounded shoulder ≥49°, thoracic kyphosis ≥42°). EMG was used to measure activation levels of UT, MT, LT, and SA, and the UT activation ratio relative to MT, LT, and SA during ten exercises. One-way ANOVA was applied for data analysis. ResultsSide-lying external rotation, standing diagonal flexion with Thera-band, and lying prone “V” demonstrated the least UT activity, with the highest MT and LT activation. The standing diagonal flexion with Thera-band elicited the highest SA activity. UT/MT, UT/LT, and UT/SA ratios were less than one in multiple exercises. Significant differences in muscle activation levels and ratios were observed across all exercises (P ≤ 0.05). ConclusionThe findings suggest significant clinical implications for UCS rehabilitation. The identified exercises effectively engage MT and LT while minimizing UT activation, addressing muscular imbalances. Favorable UT/MT, UT/LT, and UT/SA ratios further support these exercises in correcting UCS. These exercises may help counteract the underlying muscular imbalance in UCS by promoting a more balanced activity ratio among the shoulder girdle muscles, potentially improving posture and reducing UCS symptoms.

Correlation between Cranio-Vertebral Angle and Muscle Activity According to Body Movements in Forward Head Posture

The purpose of this study is to determine the correlation between FHP and how it may affect muscle activity during raising the arm and loss of body balance, 40 young people participated. All subjects will have their cranio-vertebral angle (CVA) and muscle activity of the serratus anterior (SA), upper trapezius (UT), and lower trapezius (LT), static balance index, and central pressure excursion index (CPEI) measured. Muscle activity was measured using TeleMyo 2400(Noraxon U.S.A., Inc., Scottsdale, AZ, USA), and static balance indicators and CPEI were measured using the MatscanVersaTek system (Tekscan Inc., MA). Spearman correlation analysis was used to determine the correlation between variables. CVA and SA, UT, and LT all showed significant correlation, positive correlation with SA(r=0.429/p=0.006) and LT(r=0.377/p=0.017), and negative correlation with UT(r=-0.473/p=0.007) (Table 2). CVA showed a moderate level of negative correlation with AREA(r=0.-0.420 /p=0.007) and L-R distance(r=-0.508 /p=0.000) among balance indicators, and did not show a significant correlation with CPEI (Table 3). In people with more severe FHP, SA, and LT muscle activity tended to be lower, UT muscle activity tended to be higher, and static balance ability was lower. According to the results of this study, FHP can have a negative effect on various factors of the body, such as arm movement and static balance, suggesting that establishing correct posture is necessary to prevent secondary physical problems.

Effects of laptop screen height on neck and shoulder muscle fatigue and spine loading for office workers.

Due to the unfavourable neck-shoulder muscle loads caused by poor posture, the people who use the laptop for a long time may face the risk of neck and shoulder injuries. The purpose of this study investigates the impact of the screen height on the muscle activation of head flexion, neck and shoulder, and the cervical spine torque to provide the favorite screen height for laptop user. Twelve healthy young participants completed a15-minute task of the reading at the four different screen heights. sEMG signals of the splenius capitis (SC) and upper trapezius (UT) were measured and calculated the root mean square (RMS) and mean power frequency (MPF) to determine muscle fatigue. The different height of laptop users was simulated and the forces on the spine of users at different screen heights were analyzed by Jack. Adjusting the height of the laptop screen can effectively reduce head flexion and muscle activity of SC and UT, and has a positive effect on reducing fatigue of SC, but has no significant effect on UT. Adjusting the height of the laptop screen can delay the occurrence of SC muscle fatigue to a certain extent. The joint analysis of sEMG spectrum and amplitude reports that the screen heights of D15 and D45 have the highest and the lowest frequency of fatigue, respectively. At the same time, the moment of spineT1/T2 and spineL4/L5 decrease with the increase of screen height.

Comparison of upper and lower trapezius electromyographic activity during Y-raise exercise with and without isometric adduction in healthy volunteers

BACKGROUND: Lower trapezius (LT) plays an important role in maintaining the stability of the scapula. Sufficient activation of LT can reduce the risk of rotator cuff tear and shoulder impingement syndrome. The Y-raise exercise has been recommended for effective LT activation. However, the upper trapezius (UT) can be co-activated during universal Y-raise exercise. OBJECTIVE: This study aimed to compare the activity of the UT, LT, and serratus anterior (SA) during Y-raise exercise with and without isometric adduction (IAD) using Thera-Band. METHODS: 21 healthy males voluntarily participated in the study. The participants were asked to perform Y-raise exercise with and without IAD using Thera-Band. Surface electromyography was used to measure the muscle activity of UT, LT, and SA during Y-raise exercise with and without IAD. Paired t-test was used to analyze the significance of the muscle activity of UT, LT, and SA as well as the activity ratio of LT/UT and LT/SA. The significance level was set at α= 0.05. RESULTS: Compared with Y-raise exercise without IAD, the muscle activity of UT and SA decreased (p= 0.001 and p= 0.003, respectively), whereas that of LT increased (p= 0.038) during Y-raise exercise with IAD. Additionally, the activity ratio of LT/UT and LT/SA was greater during Y-raise exercise with IAD (p= 0.001 and p= 0.001, respectively). CONCLUSION: Y-raise exercise with IAD using Thera-Band is recommended as an efficient exercise to selectively activate the LT and increase the activity ratio of LT/UT and LT/SA.

The Impact of Indoor and Outdoor Air Temperature Variations on Upper Trapezius Muscle Activity

The Impact of Indoor and Outdoor Air Temperature Variations on Upper Trapezius Muscle Activity

Effect of different postures and loads on joint motion and muscle activity in older adults during overhead retrieval.

Introduction: Pain is a common health problem among older adults worldwide. Older adults tend to suffer from arm, lumbar, and back pain when using hanging cabinets. Methods: This study used surface electromyography to record muscle activity and a motion capture system to record joint motion to research effects of different loads and retrieval postures on muscle activity and joint range of motion when older adults retrieve objects from a high place, to provide optimised feedback for the design of hanging cabinet furniture. Results: We found that: 1) The activity of BB (Biceps brachii) on the side of the body interacting with the cabinet door was greater than that of UT (Upper trapezius) and BR (Brachial radius) when retrieving objects from a high place, the activity of UT on the side of the body interacting with a heavy object was greater than that of BB and BR. 2) The activity of UT decreases when the shoulder joint angle is greater than 90°, but the activity of BB increases as the angle increases. In contrast, increasing the object's mass causes the maximum load on the shoulder joint. 3) Among the different postures for overhead retrieval, alternating between the right and left hand is preferable for the overhead retrieval task. 4) Age had the most significant effect on overhead retrieval, followed by height (of person), and load changes were significantly different only at the experiment's left elbow joint and the L.BR. 5) Older adults took longer and exerted more effort to complete the task than younger adults, and static exercise in older adults may be more demanding on muscle activity in old age than powered exercise. Conclusion: These results help to optimise the design of hanging cabinet furniture. Regarding the height of hanging cabinets, 180 cm or less is required for regular retrieval movements if the human height is less than 150 cm. Concerning the depth of the hanging cabinets, different heights chose different comfort distances, which translated into the depth of the hanging cabinets; the greater the height, the greater the depth of the hanging cabinets to use.

Effect of a slump posture on pain, proprioception, and electrical activity of the muscles in office workers with chronic non-specific neck pain. A retrospective study

BackgroundThe impact of computer typing in a slump posture on pain, proprioception and muscle recruitment has not been extensively investigated. Therefore, the purpose of this study was to evaluate the extent of pain, proprioception and muscle activity resulting from computer typing in a slump posture in women who already suffer from chronic neck pain. MethodsThis cross-sectional study was conducted between May 20 to July 10, 2021. A total of 15 female 42-(±4.96)-year-old office workers with chronic non-specific neck pain participated in this study. Before and after 60 min of computer typing in a slump posture, proprioception and pain were measured using an inclinometer and visual analog scale (VAS), respectively. The activity of the cervical erector spine (CES) and upper trapezius (UT) muscle was also measured before and after the slump-posture computer typing, in upright, forward, and slump postures. Results: Paired-samples t-tests showed that pain was increased and proprioception in all directions (flexion, extension, right and left lateral flexion, and right, and left rotation) was less accurate (P < 0.05) after 60 min computer typing. The CES and UT muscle activity were elevated more in the forward head and slump posture than in the upright posture (P < 0.05). ConclusionSixty minutes computer typing in a slump posture increased neck pain, resulted in a decreased proprioception in the neck and was accompanied by an increased activity of the neck musculature.

Comparing Three Wearable Brassiere Braces Designed to Correct Rounded Posture.

Rounded shoulder posture (RSP) causes shoulder pain and can lead to shoulder impingement and thoracic outlet syndromes, ultimately resulting in a frozen shoulder. Altered scapular positions in RSP patients affect muscle activity. Many studies have explored methods to correct and prevent RSP, including shoulder braces, muscle strengthening, stretching, and inhibition techniques. Using a shoulder brace reduces RSP and improves shoulder discomfort and function, similar to conventional rehabilitation. However, despite their effectiveness, these braces are bulky and inconvenient, which makes continuous daily wear challenging. This is especially true for women who are sensitive to their appearance. To address this issue, methods have been developed to convert women's underwear bra straps into braces. This study aimed to evaluate the immediate effects of three underwear-mounted rounded shoulder braces and to identify the brace that is most effective in decreasing RSP and upper trapezius (UT) muscle activity and increasing lower trapezius (LT) muscle activity in patients with RSP. The study included 18 patients with an RSP. The RSP amount and UT and LT muscle activities were measured before and after three interventions. The interventions were scapular posterior tilting (SPT) exercises with the X strap, X + 8 strap, and inner brace. Compared with the baseline value, the RSP amount was significantly lower with the three braces. The RSP was significantly lower with the X + 8 strap and the inner brace than with the X strap. The inner brace showed significantly lower UT muscle activity than those with the X strap and X + 8 straps and significantly greater LT muscle activity than that with the X + 8 strap. These results show underwear-mounted braces as a potential RSP solution, but long-term sustainability and improving comfort, especially for those concerned about appearance, require further research and development.

The effect of deep neck flexor endurance on craniovertebral angle changes and neck and shoulder muscle activities during a computer task

ABSTRACT The deep neck flexors are important for maintaining neck posture by stabilizing and supporting it through low-intensity contraction, ensuring static endurance. The subjects performed computer tasks after having their deep neck flexor endurance measured using a pressure biofeedback unit. The craniovertebral angle (CVA) and the muscle activities were measured while participants were completing computer tasks for 10 min. The deep neck flexor endurance was significantly negatively correlated with CVA changes at 0–2 min. The deep neck flexor endurance was significantly negatively correlated with sternocleidomastoid muscle and upper trapezius activity at 0–2 min. The deep neck flexor endurance negatively predicted CVA changes at 0–2 min and explained 28.8% of the variance in the CVA changes. The lower the deep neck flexor endurance, the earlier the simultaneous changes occurred in the CVA and the neck and shoulder muscle activities during computer tasks.

The effect of EMG biofeedback training on muscle activation in an impingement population

Subacromial impingement syndrome (SAIS) is one of the most diagnosed causes of pain in the upper extremity. The purpose of this study was to investigate muscle activity between asymptomatic and SAIS shoulders on the same subject while understanding the effectiveness of EMG biofeedback training (EBFB) on bilateral overhead movements. Ten participants (7 male), that tested positive for 2/3 SAIS clinical tests, volunteered for the study. Bilateral muscle activity was measured via electrodes on the upper trapezius (UT), lower trapezius (LT), serratus anterior (SA), and lumbar paraspinals (LP). Participants performed bilateral scapular plane overhead movements before and after EBFB. EBFB consisted of 10 bilateral repetitions of I, W, T, and Y exercises focused on reducing UT and increasing LT and SA activity. Prior to EBFB, no significant difference in muscle activity was present between sides. A significant main effect of time indicated that after EBFB both sides exhibited reduced UT activity at 60° (p=0.003) and 90° (p=0.036), LT activity was increased at all measured humeral angles (p<0.0005), and SA muscle activity was increased at 110° (p=0.001). EBFB in conjunction with scapular based exercise effectively alters muscle activity of asymptomatic and symptomatic scapular musculature.

Effect Of Different Grip Position And Shoulder- Abduction Angle On Muscle Strength And Activation During The Seated Cable Row

The purpose of this study was to compare the peak force and electromyographic activation in different techniques of the seated row. Eleven recreationally trained male (28±5 years, 176±5 cm, 94±16 kg) and ten female (27±5 years, 168±8 cm, 65±11 kg ) performed an isometric and a dynamic assessment of the seated cable row and the preacher curl: pronated grip (PRO), supinated grip (SUP), neutral grip (NEU), 30° (30°), 60° (60°), 90° (90°) of shoulder abduction, and cable preacher curl (PC). Peak force and muscle activation of upper trapezius, middle trapezius, upper latissimus, lower latissimus, posterior deltoid, and biceps bracii were recorded during the isometric and dynamic assessment of the exercises. p values&lt;0.05 were considered statistically significant. The peak force was greater when shoulder abduction angle was closer to 0° (PRO, SUP, and NEU) and decreased as abduction angle increased (60° and 90°). Muscle activation of the upper back (upper trapezius, middle trapezius) and posterior deltoid increased as abduction angle increased (60° and 90°) on both isometric and dynamic analysis. Muscle activation of the upper and lower latissimus increased as abduction angle was closer to 0° (PRO, SUP, and NEU) on both isometric and dynamic analysis. Biceps brachii activation on both isometric and dynamic analysis during the PC was greater than all other rowing conditions; among the rowing techniques, BB activation was greater during SUP, NEU, and 90° techniques. In conclusion, the closer to 90° shoulder abduction the greater UT, MT, and PD activity, on the other hand, the closer to 0° shoulder abduction the greater peak force, UL, and LL activity during the variations of the rowing exercise.

Total forearm support during a typing task may reduce the risk of Trapezius' Myalgia development

ObjectiveEvaluate the influence of alternating the position of the upper limbs, between fully supported and unsupported forearms, in the Upper Trapezius (UT) activity during a typing task on a straight-edged desk. BackgroundErgonomic barriers, such as reduced desk area, is one of the reasons that force computer users to work without supporting their forearms. Unsupported forearms may lead to increased UT muscle fatigue, increasing the potential for lesions, with Trapezius Myalgia (TM) being a possible outcome. Method15 healthy volunteers were assessed (6 females, average age of 3,7 ± 9,5 years old). The protocol included an alternated position of forearms every 5 min between fully supported and unsupported forearms, with a 20-min total duration of a typing task. Surface electromyography readings were collected from both UTs. ResultsSignificant differences were found in the variation of the EMG signal between the two positions for the non-dominant arm after 10 min (p < .05) of typing. The non-dominant UT registered higher levels of activity than the dominant UT. Supported forearms reduced the electrical activity in both UTs, with a greater difference in the non-dominant. ConclusionThis study consolidates the current knowledge that unsupported upper limb during typing tasks significantly increases UT's electrical activity. By fully supporting the forearm, that activity is reduced. Females and the non-dominant UT showed higher electrical activity, potentially increasing the risk of developing TM. ApplicationHealthcare providers, safety and health professionals, and ergonomists should be mindful of the forearm position when advising computer users to prevent TM.

The effect of tablet tilt angles and time on posture, muscle activity, and discomfort at the neck and shoulder in healthy young adults.

Although young adults regularly perform tablet writing, biomechanics during the tablet writing with different tilt angles has not been studied. The objective of this study was to compare posture, muscle activity, and discomfort at the neck and shoulder between tablet writing with 0° (horizontal) and 30° tablet tilt angles over 40 minutes in healthy young adults. Twenty participants wrote continuously for 40 minutes on a tablet with both tilt angles in a randomized order. Between conditions, there was a 5-minute activity break. Differences in neck and shoulder posture, muscle activity, and discomfort between both tablet tilt angles and changes in the outcomes every 10 minutes over 40 minutes were investigated. With the tilted tablet, there were lower neck flexion (Z = -4.637, P<0.001), lower shoulder extension (Z = -3.734, P<0.001), and lower neck Visual Analogue Scale (VAS) (left; Z = -4.699, P<0.001 and right; Z = -3.874, P<0.001) as compared to the no tilt condition. However, the right upper trapezius muscle activity was higher in the tilted condition as compared to the no tilt one. Over 40 minutes, the neck VAS (left; χ2(4) = 30.235, P<0.001 and right; χ2(4) = 32.560, P<0.001) and heart rate variability (χ2(4) = 12.906, P = 0.012) showed notable increases after 20 minutes compared to baseline. In conclusion, adjusting the tablet tilt to 30° and limiting time spent to 20 minutes are recommended for young adults during the tablet writing to prevent neck problems.

The Effects of Scapular Stabilization Exercises Accompanied by Spine Stabilization Exercises Using An Unstable Surface on Muscle Activities for Subjects with Scapular Winging

This study was intended to inspect the influence of scapular stabilization exercises accompanied by spine stabilization exercises using an unstable surface on muscle activity in subjects with scapular winging. Thirty subjects with scapular winging participated in the experiment. The subjects were randomly divided into two groups. One group performed scapular stabilization exercises accompanied by spine stabilization exercises on an unstable surface, whereas the other group performed only scapular stabilization exercises. In order to study the influence of the intervention, the muscle activity around the shoulder was measured. According to the experimental results, the activation of the lower trapezius muscle and serratus anterior muscle increased significantly in both groups after intervention. The muscle activities of the lower trapezius and serratus anterior in the control group were not as high as those in the experimental group. Moreover, the muscle activities of upper trapezius and pectoralis major decreased significantly in both groups after the exercise interventions, but no significant difference was observed between the two groups. As a result, the scapular stabilization exercises that are widely used in clinical practice were shown to increase lower trapezius and serratus anterior activities. Moreover, a combination of such exercises with spine stabilization exercises on an unstable surface was shown to confer greater benefits than scapular stabilization exercises alone and is thus recommended.

Effects of typing positions on the upper trapezius and neck extensor muscles electromyography in office employees: A single-blind cross-sectional study.

Holding incorrect postures over a long period could lead to chronic nonspecific neck pain (CNNP) in office employees. The present study aimed to evaluate the effects of different typing positions on the activity of the neck extensor and upper trapezius (UT) muscles of office employees diagnosed with CNNP. This assessor-blinded cross-sectional study was performed on 22 female subjects with the mean age of 39.95±5.30 years. The neck extensors and UT muscle activities of the participants were assessed in the upright, forward, and slouching postures by electromyography (EMG). In addition, neck proprioception and the performance of the cervical stabilizer muscles were evaluated using an inclinometer and biofeedback pressure unit, respectively. A significant difference was observed between the cervical erector spine (CES) and UT muscle activities in the upright, forward, and slouching typing positions (P < 0.05). In addition, a difference was observed between the upright and slouching postures in these muscles. A positive correlation was denoted between CES muscle activity in the slouching and forward postures and the activation index of neck muscles (P < 0.05). Furthermore, a significant, negative correlation was observed between the UT muscle activity in the slouching posture and neck proprioception (P < 0.05). A positive correlation was also noted between the pain index and repositioning error rates (P < 0.05). CES muscle activity increased in a forward head posture, which could damage neck proprioception through causing early fatigue and stimulating a cumulative damage cycle.

The Effect of Modified Push-up Exercise Using Electromyography Biofeedback on Selection of Scapular Stabilizing Muscles

Background: The serratus anterior (SA) muscle is an important scapular stabilizer and has a profound role in retaining the scapulohumeral rhythm. Therefore, modified push-up plus (MPUP) has been advised to strengthen this muscle as a closed chain workout. However, few previous studies have reported the possibility of a reparative motion from pectoralis major (PM) that could replace and amend SA's function during push-up plus. Objectives: The current study examined MPUP's effect using biofeedback EMG on some of the selected scapular stabilizers. Methods: Sixteen healthy young subjects voluntarily participated in this study. Each subject performed push-ups, from the quadruped position, under two conditions (i.e., with or without visual and auditory biofeedback). Surface EMG measured pectoralis major, serratus anterior, and upper trapezius activity. A paired t-test was used to determine any statistically significant difference between the two conditions. Additionally, the effect size was calculated to quantify the magnitude of EMG biofeedback in each muscle. Results: MPUP training using biofeedback significantly increased SA muscle activity and decreased PM muscle activity, but there was no significant change in UT activity. Conclusions: Excessive PM activity was repressed because of biofeedback, and the workout was done with the enhancement of SA muscular activity. Thus, including biofeedback while doing MPUPs helps limit PM's supplementary action and enhance SA muscle activity.

Effects of Artificially Induced Breast Augmentation on the Electromyographic Activity of Neck and Trunk Muscles during Common Daily Movements.

A female breast can be a potential source of musculoskeletal problems, especially if it is disproportionately large. The purpose of the present study was to examine the effect of artificially induced breast volume on the EMG activity of neck and trunk musculature during common everyday movements. The EMG activity of the sternocleidomastoid (SCM), the upper trapezius (UT), and the thoracic and lumbar erector spinae (TES, LES) were recorded during 45° trunk inclination from the upright standing and sitting postures (TIST45°, TISI45°) as well as during stand-to-sit and sit-to-stand (STSI, SIST) in 24 healthy females with minimal and ideal breast volume (M-NBV, I-NBV). All movements were performed before and after increasing M-NBV and I-NBV by 1.5-, 3.0-, 4.5-, and 6-times using silicone-gel implants. Significantly higher EMG activity for TES and LES were found at 6.0- and ≥4.5-times increase the I-NBV, respectively, compared to smaller breast volumes during TIST45°. EMG activity of UT was higher, and TES was lower in M-NBV females compared to I-NBV females in all movements but were significantly different only during SIST. The female breast can affect the activity of neck and trunk muscles only when its volume increases above a certain limit, potentially contributing to muscle dysfunction.

Upper Body Muscle Activation And Measures Of Sprint Performance

PURPOSE: Effective arm swing and core muscle activation are involved in acceleration and maximal sprinting, yet muscle activity in these areas have not been measured via electromyography (EMG) during over ground sprinting trials. The purpose of this study was to explore the relationship between muscle activation of the upper body and measures of performance during sprint acceleration and maximal sprinting. METHODS: Sixteen participants (20.93 ± 0.96 yrs.; 1.71 ± 0.07 m; 67.69 ± 11.81 kg) completed six 40-m sprint trials on an outdoor track, with three from a block start and three from a split start. Muscle activation was measured via EMG in the triceps brachii, biceps brachii, upper trapezius, anterior deltoid, latissimus dorsi, erector spinae, rectus abdominis, and oblique muscles, recorded as a percentage of maximal voluntary isometric contraction. Split times recorded during each sprint were used to calculate acceleration, net horizontal force (Fh), and the ratio of Fh and resultant ground reaction force (%RF) using previously validated methods. Repeated measures multilevel modeling was used to evaluate the relationship between mean upper body muscle activation and average acceleration, Fh, and %RF during each 10-m window of the sprint. RESULTS: During the 0-10 m window, mean activation of the upper trapezius showed a significant positive relationship with acceleration (t = 2.66, p = 0.01), Fh (t = 2.20, p = 0.03), and %RF (t = 2.57, p = 0.01), erector spinae activation was positively associated with %RF (t = 2.42, p = 0.02), and biceps activation was negatively associated with Fh (t = -2.23, p = 0.03). In the 30-40 m window, there was a significant negative relationship between mean latissimus dorsi activation and %RF (t = -2.16, p = 0.04). There were no significant relationships between upper body muscle activation and indicators of sprint performance detected during the 10-20 m or 20-30 m windows. CONCLUSIONS: These results indicate that upper trapezius muscle activity is important during initial sprint acceleration, which agrees with past research on scapular restriction limiting maximal acceleration while sprinting. After the initial period of sprint acceleration, there was no evidence that greater activation of certain upper body muscles was related to improving maximal sprinting performance.

Within-Subject Changes in Shoulder Girdle Muscle Activation After Soft Tissue Mobilization of the Upper Trapezius

ObjectiveThe purpose of this study was to investigate the effect of the integrated neuromuscular inhibition technique (INIT) of the upper trapezius (UT) on shoulder muscle activity in chronic shoulder pain. MethodsTwenty-two patients (mean age 42.5 ± 16.07) with chronic unilateral shoulder pain with UT myofascial trigger points (MTrPs) (n = 27) and scapular dyskinesis received a single session of INIT (∼15 minutes for each MTrP). The pain on the visual analog scale, along with surface electromyographic activity, maximum voluntary contraction in % (in arm raising and lowering in scapular plane), and pressure pain threshold (PPT) of 5 girdle muscles UT, lower trapezius, serratus anterior, middle deltoid, and infraspinatus were measured before and immediately after treatment. Wilcoxon signed-rank test was used for analysis (at α ≤ 0.05). ResultsMuscle activity of all the muscles, especially the lower trapezius, was reduced during arm raising in the scapular plane (76.69%-71.14% [p = 0.003]). UT activity decreased during arm lowering also (56.70%-45.99% [p ˂ 0.001]). The intensity of shoulder pain reduced (50.50 mm to 22 mm, [p ˂ 0.001]), and PPT values of all 5 muscles improved post-treatment. ConclusionThe findings of this study provide preliminary evidence for the application of a single session of INIT on UT MTrPs in reducing activity in the scapular muscles, improving shoulder pain, and PPT in chronic unilateral shoulder pain.

Comparison of scapular upward rotator muscle activities and activity ratios during three scapular upward rotator strengthening exercises

BACKGROUND: The focus of exercises for restoring the imbalance between scapular upward rotator muscles – upper trapezius (UT), serratus anterior (SA), and lower trapezius (LT) – commonly aims to increase SA and LT activities while not increasing UT activity. OBJECTIVES: The purpose of this study was to compare the activity of the UT, SA, and LT muscles during scapation and protraction exercises, which are two traditional exercises, and during a newly designed scapular upward rotation (SUR) exercise. METHODS: A total of 29 healthy young adult men performed all three exercises with maximum isometric contraction. The electromyographic activities of the UT, SA, and LT were recorded. RESULTS: UT demonstrated the highest activity during scapation. SA activity was the lowest during protraction. However, no difference was found in SA activity during the performance of scapation and SUR. The SA/UT ratio was the highest during scapation. CONCLUSIONS: SUR is a new exercise that can be performed at moderate intensity for shoulder rehabilitation to restore scapular upward rotator muscle imbalance.