Hardie Rebecca, Haskew Rachel, Harris Joel, Hughes Gerwyn
Sport, Health and Exercise Subject Group, University of Hertfordshire, UK.
J Hum Kinet. 2015 Apr 7;45:39-47. doi: 10.1515/hukin-2015-0005. eCollection 2015 Mar 29.
Back pain is common in adolescents which has been associated with carrying a bag. However, there is little research examining the effects of bag style in female adolescents. The aim of the study was to investigate the effects of different bag conditions on muscle activity of the trapezius, erector spinae and latissimus dorsi muscles in female university students during walking. Twelve female university students walked on a treadmill for 5 minutes at 1.1 m/s during five conditions; control, 1 strapped rucksack, 2 strapped rucksack, ipsilateral shoulder strap and contralateral shoulder strap, each containing 10% bodyweight. Electromyography for the trapezius, erector spinae and latissimus dorsi was recorded for the last 30 s of each condition. Two-way ANOVA and paired t-tests were used to identify differences between right and left muscles and between bag conditions. Results showed that muscle activity of the left trapezius was significantly higher than the right trapezius during the 1 strap rucksack condition. For the left trapezius, the 2 strapped rucksack and the control condition had significantly lower muscle activity compared to the 1 strapped rucksack and the ipsilateral shoulder strap. For the left erector spinae muscle, there was significantly greater muscle activity when wearing the contralateral shoulder strap compared to the control. For the right erector spinae, significantly lower muscle activity was observed when wearing the 2 strapped rucksack compared to the ipsilateral shoulder strap and contralateral shoulder strap. There were no significant differences in muscle activity of the latissimus dorsi muscles between any of the bag conditions. These findings suggest that a two strapped rucksack should be used when carrying loads to reduce spinal muscle activity which may, in turn, reduce reports of back pain in female adolescents.
背痛在青少年中很常见，这与背负书包有关。然而，很少有研究探讨书包款式对女性青少年的影响。本研究的目的是调查不同书包条件对女大学生行走时斜方肌、竖脊肌和背阔肌肌肉活动的影响。12名女大学生在五种条件下以1.1米/秒的速度在跑步机上行走5分钟；分别为对照组、单肩背包、双肩背包、同侧肩带背包和对侧肩带背包，每种负重均为体重的10%。在每种条件的最后30秒记录斜方肌、竖脊肌和背阔肌的肌电图。采用双向方差分析和配对t检验来确定左右肌肉之间以及不同书包条件之间的差异。结果显示，在单肩背包条件下，左侧斜方肌的肌肉活动显著高于右侧斜方肌。对于左侧斜方肌，与单肩背包和同侧肩带背包相比，双肩背包和对照组的肌肉活动显著更低。对于左侧竖脊肌，与对照组相比，佩戴对侧肩带背包时肌肉活动显著更大。对于右侧竖脊肌，与同侧肩带背包和对侧肩带背包相比，佩戴双肩背包时观察到肌肉活动显著更低。在任何一种书包条件下，背阔肌的肌肉活动均无显著差异。这些发现表明，负重时应使用双肩背包以减少脊柱肌肉活动，这反过来可能会减少女性青少年背痛的报告。
