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Effects of sitting posture and jaw clenching on neck and trunk muscle activities during typing
Author(s) -
Tomita Yosuke,
Suzuki Yoshitaka,
Tanaka Yuto,
Hasegawa Yoko,
Yoshihara Yasutomo,
Okura Kazuo,
Matsuka Yoshizo
Publication year - 2021
Publication title -
journal of oral rehabilitation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 93
eISSN - 1365-2842
pISSN - 0305-182X
DOI - 10.1111/joor.13152
Subject(s) - medicine , trunk , sitting , electromyography , neck muscles , physical medicine and rehabilitation , physical therapy , orthodontics , anatomy , ecology , pathology , biology
Neck pain is one of the most common musculoskeletal complaints. Evidence suggests that increased activities of neck and trunk muscles are one of the mechanisms related to neck pain. Jaw clenching and sitting posture may modulate the muscle activity in neck and trunk muscles during typing. The present study aimed to assess the effects of different postural positions and clenching conditions on neck and trunk muscle activities. Thirteen healthy adults (39.8 ± 5.0 years) performed computer typing tasks in four conditions (two postural positions [upright vs slouched] and two jaw clenching conditions [clenching vs non‐clenching]). Integrated surface electromyography (iEMG) was measured in sternocleidomastoid (SCM), upper trapezius (uTP) and middle trapezius (mTP) muscles and compared between conditions. The Friedman and Wilcoxon signed‐rank tests with Bonferroni's corrections were used to estimate the condition‐specific differences in the iEMG data. The statistical significance level was set at 5%. In both postural positions, iEMG SCM was significantly greater under the jaw clenching than under the non‐clenching condition (χ 2 = 21.700, P < .01). Under both jaw clenching conditions, iEMG uTP was significantly greater in the slouched than in the upright postural position (χ 2 = 23.182, P < .01). No significant differences in iEMG mTP were seen across conditions (χ 2 = 5.018, P = .10). Sitting posture and jaw clenching appear to influence activities of different muscles.