The Prevalence of Playing-Related Musculoskeletal Disorders of Music College Freshmen Playing String Instruments / 대한산업의학회지

OBJECTIVES: This study was conducted to investigate the prevalence of playing-related musculoskeletal disorders (PRMDs) of some music college freshmen majoring in string instruments. METHODS: The study subjects were 199 freshmen majoring in strings at three colleges in Seoul and surrounds. The symptom prevalence and related factors of PRMDs were surveyed with a self-administered questionnaire. The Southampton Protocol was used to diagnose PRMDs. RESULTS: The freshmen had played for 9 years and 7 months on average. The symptom prevalence of PRMDs according to the modified-NIOSH surveillance criteria was 73.4%. The shoulder was the most prevalent symptom complaint site. The prevalence of PRMDs by the Southampton Protocol was 54.3% and myofascial pain syndrome was the most common. The instrument (violin or viola vs. cello or bass), regular breaks, self perceived evaluation of playing posture and regular computer use had a significant association with the symptom prevalence of PRMDs in univariate logistic regression analysis (p<0.05). The instrument, regular breaks and regular computer use were significant variables affecting the symptom prevalence of PRMDs in multivariate logistic regression analysis (p<0.05). CONCLUSIONS: This study suggests that music college freshmen playing strings are a high risk group for musculoskeletal disorders. Therefore, the prevention of PRMDs requires the establishment of an ergonomic playing-environment, and the education of comfortable posture and stretching program such as musical warming up and physical stretching. It is especially important to form an effective treatment and rehabilitation system based on earlier diagnosis for musicians who are suffering from the PRMDs.

Deterioration of Accommodative Esotropia during Part-time Occlusion Therapy

The authors report two cases of suddenly deteriorated accommodative esotropia with amblyopia during part-time occlusion therapy. A 7-year-old girl with right accommodative esotropia, which was well controlled, showed marked increase in esodeviation after part-time occlusion and regained orthophoria without occlusion. This phenomenon was repeated. Recession of both medial recti was performed and orthophoria was well maintained at both distant and near targets. Accommodative esotropia of a 9-year-old boy with glasses also showed a striking increase in esodeviation after part-time occlusion. The authors recommended wearing only glasses without occlusion or surgery and he recovered fusion. Three months later, orthophoria was maintained at distant target, with 8PD esophoria at near target with glasses. Although this complication should be considered before occlusion therapy, it must be taken continuously if needed, because an increase of the deviation size with occlusion may simply reflect a true deviation and may not be a poor prognostic sign.

Change of Foot Measurements with Weight Bearing by 3-D Foot Scanner

OBJECTIVE: To evaluate the influence of weight-bearing on foot shape measured by 3-D foot scanner. METHOD: Forty-two feet of twenty-one normal subjects were studied. The foot length, width, girth and arch parameters under non weight-bearing and weight-bearing conditions were measured by 3-D foot scanner (Nexcan(R), K & I, Korea), analysis software (EnFOOT(r), K & I, Korea) and 3-D foot arch measurement program. RESULTS: The foot length, ball width, ball girth, waist girth, instep girth, short heel girth, long heel girth and length from heel point to proximal arch point significantly increased under weight-bearing condition (p<0.01). However, vamp height, waist height, instep height, length of arch, height of arch, width of arch, length from heel point to distal arch point, maximal arch height and volume of arch were significantly decreased under 50% weight-bearing condition (p<0.01). CONCLUSION: Foot parameters associated with length, width and girth increased but volume, width, length, and height of medial longitudinal arch decreased under weight bearing condition. We suggest that these findings under weight- bearing condition result from the pronation of subtalar joint and the decrement of heights of transverse and longitudinal arch heights.

Three Dimensional Analysis of the Medial Longitudinal Arch of Foot

OBJECTIVE: To evaluate and quantify the medial longitudinal arch of foot using a 3-D foot scanner and 3-D arch measurement program. METHOD: 997 subjects (363 men and 634 women) were selected. The foot length, width, girth and medial longitudinal arch parameters were measured with a 3-D foot scanner (Nexcan(r), K&I, Korea), analysis software (EnFOOT(R), K&I, Korea) and 3-D measurement program of the medial longitudinal arch. RESULTS: The mean arch lengths were 100.3 mm for men, 90.4 mm for women. The mean arch height and arch volume in both genders were 14.7 mm, 12.1 mm and 10.3 cm3, 6.0 cm3, respectively. We compared the arch parameters of both genders by univariate analysis of variance and in most cases the parameters of men were larger than those of women. Moderate positive relationships were found between foot length and arch width of talonavicular joint in cases of men, foot length and length from heel point to distal arch point in both genders (Pearson correlation coefficient > 0.3, p<0.01). CONCLUSION: We evaluated the medial longitudinal arch of Korean feet three dimensionally. These data sould be a useful reference for making shoes, insoles, and orthoses.