Background: Although the scapular posterior tilt movement could facilitate the lower trapezius (LT) muscle activity, no study identified the effects of the scapular posterior tilt movement on the selective activation of the LT muscle during prone shoulder extension. Objectives: To examine the influences of additional scapular posterior tilt on electromyography (EMG) of the upper trapezius (UT) and the LT muscles during prone shoulder extension. Design: Cross-sectional study. Methods: There were 15 asymptomatic male participants in this study who performed prone shoulder extension with and without scapular posterior tilt movements. For the scapular posterior tilt movements, participants performed visual biofeedback training for scapular movement using motion sensor. During the exercises, the EMG activity of the UT and LT was recorded using surface EMG system. Results: The EMG activity of the LT significantly increased during prone shoulder extension with scapular posterior tilt compared to that of general prone shoulder extension, whereas that of the UT was not significantly different between the two exercises. Moreover, scapular posterior tilt application significantly decreased UT/LT muscle activity ratio. Conclusion: Scapular posterior tilt movement may be emphasized during exercise when facilitating LT muscle activation.

Background: Lower trapezius muscle function is important for the prevention and treatment of shoulder injuries. However, scapular posterior tilt movement has been overlooked in lower trapezius strengthening exercise programs. Objective: To examine the effects of prone arm lifting with scapular posterior tilt (PALSPT) on trapezius muscles. Design: Crossover study Methods: 17 healthy males were recruited for participation in this study. Participants performed backward rocking diagonal arm lifting (BRDAL) and PALSPT. To train participants in scapular posterior tilt movements for PALSPT, visual biofeedback of scapular movements was provided using a motion sensor. Electromyography (EMG) activities of the middle and lower trapezius were recorded using a surface EMG system. Differences in middle and lower trapezius muscle activity between BRDAL and PALSPT exercises were analyzed. Results: Lower trapezius muscle activity was significantly greater during PALSPT than during BRDAL (p=.006). Although greater EMG activity was observed in the middle trapezius during PALSPT than during BRDAL, this difference was not significant (p=.055). Conclusions: The results of the present study indicate that scapular posterior tilt movements must be considered in lower trapezius muscle strengthening programs.

Background: The unilateral prone arm lift (UPAL) is commonly used to exercise the lower trapezius muscle. However, overactivation of the upper trapezius can induce pain during UPAL exercises in subjects with upper trapezius tenderness. Objects: The purpose of this study was to investigate the effects of position of ipsilateral neck rotation (INR) on the inhibition of upper trapezius muscle activity and the facilitation of the lower trapezius muscle when performing UPAL exercises. Methods: In total, 19 subjects with upper trapezius tenderness were recruited for the study. Electromyographic (EMG) activity was measured in the upper, middle, and lower trapezius muscles during UPAL with and without INR position. Wilcoxon signed-rank test was used to compare EMG activity in the trapezius muscles and the muscle ratios. Results: EMG activity in the upper trapezius muscles was decreased significantly in the INR condition compared to without the position with INR during UPAL exercises (p<.05). EMG activity in the middle and lower trapezius was not significantly different between the with and without INR conditions (p>.05). However, the ratio of lower to upper trapezius activation showed a significant increase in the INR condition compared to the without INR condition (p<.05), indicating greater lower trapezius activation relative to the upper trapezius in the INR position than in the without INR position. Conclusions: The EMG results obtained in this study suggest that the position with INR reduced overactivation in the upper trapezius and improved muscle imbalance during lower trapezius exercises in individuals with upper trapezius tenderness.

Violinists tend to position the neck asymmetrically to hold the violin between the chin and the left shoulder. Asymmetrical neck posture may induce unilateral neck pain. Previous studies have suggested that individuals with unilateral neck pain exhibit reduced muscle strength of the lower trapezius, but no study has investigated violinists with unilateral neck pain. To this end, we recruited 18 violinists with unilateral neck pain for the present study in which the side on which neck pain was experienced, pain duration, and intensity were recorded. Lower trapezius strength was measured bilaterally in each subject using a handheld dynamometer. Significant differences in lower trapezius strength were evident between the ipsilateral and contralateral sides of neck pain (p＜.05). No significant association between neck pain intensity or duration, and the extent of a deficit in lower trapezius strength, was evident (both p＞;.05). The association between the sides of weakened lower trapezius strength and neck pain was significant (p＜.05). In conclusion, violinists with unilateral neck pain exhibited significantly less lower trapezius strength on the ipsilateral compared to the contralateral side of the pain. Unilateral neck pain more frequently involved the left side of the neck, which is used to stabilize the violin during playing. Thus, our study suggests that a possible relationship exists between muscle weakness in the lower trapezius and neck pain.

The lower trapezius muscle is an important stabilizer and primary mover of the scapula. The potential use of ultrasound imaging to evaluate scapular muscle function warrants investigation. The purpose of this study is to use ultrasound imaging for determining the effectiveness of 4 different isometric exercises for maximally activating the lower trapezius muscles in healthy subjects. Twenty-eight (14 men and 14 women) volunteers were recruited for this study. Thickness measurements of the lower trapezius muscles were recorded during 4 exercises: latissimus pulldown (LP), prone V-raise (PV), prone row (PR), and modified prone cobra (MP). Lower trapezius muscle thickness was measured 3 times by 2 investigators at a point 3 cm lateral to the lateral edge of the T8 spinous process. The order of 4 exercise execution was randomized for each participant. To identify statistical significance, one-way ANOVA with repeated measures was used with the significance level of .05. Intraclass correlation coefficient (ICC) for intra-reliability was .86~.98 and inter-rater reliability .83~.96 for the lower trapezius, respectively (p<.01). Thickness changes in the lower trapezius muscles between the relaxed and contracted states in men were as follows: LP (, 182%), MP (, 167%), PV (, 149%), and PR (, 133%). In women the values were as follows: LP (, 163%), MP (, 131%), PV (, 129%), and PR ( mm, 100%). Thickness of the lower trapezius muscles significantly differed between exercises in both the gender (p<.01). The LP was the most effective exercise for increasing the activation of the lower trapezius muscle in both the gender. We recommend performing the LP exercise for strengthening the lower trapezius muscles.

The purpose of this study was to compare electromyography (EMG) activity for the middle and lower trapezius muscle according to various shoulder abduction angles. Thirty healthy male subjects were recruited for this study. Each subject performed three repetitions of horizontal abduction at 75˚, 90˚, 125˚, 160˚, and 180˚ of shoulder abduction angle in a prone position. Surface EMG activity was recorded from the middle and lower trapezius while the subjects held for five seconds at a predetermined position. The EMG activity was normalized using the maximal voluntary isometric contraction (MVIC) elicited using a manual muscle testing technique. A repeatedly measured ANOVA was performed by Bonferroni's post hoc test. The EMG activity of the middle and lower trapezius was significantly different among shoulder abduction angles (p<.05). The greatest level of muscle activity for the middle and lower trapezius were demonstrated at and of shoulder abduction angle, respectively. These results suggest that middle and lower trapezius strengthening exercise and manual muscle testing should be performed at different shoulder abduction angles.