Eva-Maj Malmström1,2, Joakim Olsson3,4, Johan Baldetorp5,6, Per-Anders Fransson7. 1. Department of Pain Rehabilitation, Skåne University Hospital, Lasarettsgatan 13, 22185, Lund, Sweden. eva-maj.malmstrom@med.lu.se. 2. Department of Otorhinolaryngology, Clinical Sciences, Lund, Lund University, 22185, Lund, Sweden. eva-maj.malmstrom@med.lu.se. 3. Department of Health Sciences, Faculty of Medicine, Lund University, Box 117, 22100, Lund, Sweden. joakim.olsson@resursteamet.se. 4. Resursteamet i Stockholm AB, Katrinebergsvägen 6, 117 43, Stockholm, Sweden. joakim.olsson@resursteamet.se. 5. Department of Health Sciences, Faculty of Medicine, Lund University, Box 117, 22100, Lund, Sweden. johan.baldetorp@skane.se. 6. Vårdcentralen Kirseberg, Simrisbanvägen 10, 205 02, Malmö, Sweden. johan.baldetorp@skane.se. 7. Department of Otorhinolaryngology, Clinical Sciences, Lund, Lund University, 22185, Lund, Sweden. Per-Anders.Fransson@med.lu.se.
Abstract
PURPOSE: Long-term use of unfavorable postures, congenital deformations and degenerative processes associated with aging or disease may generate an increased thoracic curvature resulting in pain and disability. We wanted to examine whether a slouched postural alignment with increased thoracic kyphosis changes the shoulder kinematics and muscle activity in upper trapezius (UT), lower trapezius (LT) and serratus anterior (SA) during arm elevation. The aim was to determine if a slouched posture influences range of motion, muscle activation patterns, maximal muscle activity and the total muscle work required when performing arm elevations. METHOD: Twelve male subjects (23.3 ± 1.5 years) performed maximum arm elevations in upright and slouched postures. A combined 3D movement and EMG system recorded arm movements and spine curvature simultaneously with EMG activity in the UT, LT and SA. RESULTS: Slouched posture affected the biomechanical conditions by significantly decreasing maximum arm elevation by ~15° (p < 0.001) and decreasing arm movement velocity by ~8 % during movements upwards (p < 0.001) and downwards (p = 0.034). The peak muscle activity increased in all muscles: UT (p = 0.034, +32.3 %), LT (p = 0.001, +48.6 %) and SA (p = 0.007, +20.9 %). The total muscle work increased significantly in the slouched posture during movements upwards: UT (p = 0.003, +36.6 %), LT (p < 0.001, +89.0 %), SA (p = 0.002, +19.4 %) and downwards: UT (p = 0.012, +29.8 %) and LT (p < 0.001, +122.5 %). CONCLUSION: An increased thoracic kyphosis was found associated with marked increased physical costs when performing arm movements. Hence, patients suffering from neck-shoulder pain and disability should be investigated and treated for defective thoracic curvature issues.
PURPOSE: Long-term use of unfavorable postures, congenital deformations and degenerative processes associated with aging or disease may generate an increased thoracic curvature resulting in pain and disability. We wanted to examine whether a slouched postural alignment with increased thoracic kyphosis changes the shoulder kinematics and muscle activity in upper trapezius (UT), lower trapezius (LT) and serratus anterior (SA) during arm elevation. The aim was to determine if a slouched posture influences range of motion, muscle activation patterns, maximal muscle activity and the total muscle work required when performing arm elevations. METHOD: Twelve male subjects (23.3 ± 1.5 years) performed maximum arm elevations in upright and slouched postures. A combined 3D movement and EMG system recorded arm movements and spine curvature simultaneously with EMG activity in the UT, LT and SA. RESULTS: Slouched posture affected the biomechanical conditions by significantly decreasing maximum arm elevation by ~15° (p < 0.001) and decreasing arm movement velocity by ~8 % during movements upwards (p < 0.001) and downwards (p = 0.034). The peak muscle activity increased in all muscles: UT (p = 0.034, +32.3 %), LT (p = 0.001, +48.6 %) and SA (p = 0.007, +20.9 %). The total muscle work increased significantly in the slouched posture during movements upwards: UT (p = 0.003, +36.6 %), LT (p < 0.001, +89.0 %), SA (p = 0.002, +19.4 %) and downwards: UT (p = 0.012, +29.8 %) and LT (p < 0.001, +122.5 %). CONCLUSION: An increased thoracic kyphosis was found associated with marked increased physical costs when performing arm movements. Hence, patients suffering from neck-shoulder pain and disability should be investigated and treated for defective thoracic curvature issues.
Authors: E Schulte; L A C Kallenberg; H Christensen; C Disselhorst-Klug; H J Hermens; G Rau; K Søgaard Journal: Eur J Appl Physiol Date: 2005-02-04 Impact factor: 3.078
Authors: Hongying Liang; Suiqing Yu; Man Hao; Weixin Deng; Ming Lin; Zheng Zhang; Chunlong Liu Journal: Med Biol Eng Comput Date: 2022-08-30 Impact factor: 3.079