Although military body armor is an effective life saver, it considerably loads more weight on the warfighters, increasing the risk of musculoskeletal injury. This study investigated the immediate and prolonged effects of wearing body armor on timing aspect of lumbo-pelvic coordination during the toe-touch (TT) and two-legged-squat (TLS) tests. A cross-over study design was used wherein twelve asymptomatic and gender-balanced individuals completed two experimental sessions with and without body armor. A session included two similar sets of tests, before and after exposure to a treadmill walk, containing a TT and a TLS test with ten cycles of fast bending and return. Reflective markers were attached on the participants to capture the kinematics of body segments in conjunction with a motion capture system. The mean absolute relative phase (MARP) and deviation phase (DP) between the thorax and pelvis were calculated for each test. The pre-walk MARP in the return was significantly larger with versus without body armor (p = 0.022), while there were no significant effects of body armor on the other outcome measures. In addition, the pre-walk MARP and DP in the bending and return, as well as the walk-induced changes in the MARP in the bending phase were significantly larger in TLS versus TT (p < 0.026). Therefore, using a body armor immediately made the lumbo-pelvic coordination less in-phase during return, but no prolonged effects were found. Further investigation is necessary to specify chances wearing a body armor increases the risk of musculoskeletal injuries in the lower back and lower extremities joints.

尽管军用防弹衣可以有效地挽救生命，但它给战斗人员带来了更大的负担，增加了肌肉骨骼受伤的风险。这项研究调查了在脚趾接触（TT）和两足下蹲（TLS）测试期间，穿着防弹衣对腰-骨盆协调的计时方面的即时和长期影响。使用交叉研究设计，其中十二名无症状和性别平衡的个体在有和没有防弹衣的情况下完成了两次实验。一个环节包括两组相似的测试，分别在跑步机行走前后进行，包括一次TT和TLS测试以及十次快速弯曲和恢复。反射标记贴在参与者身上，以结合运动捕捉系统捕捉身体的运动学。对于每个测试，计算胸腔和骨盆之间的平均绝对相对相位（MARP）和偏差相位（DP）。在没有防弹衣的情况下，返回前的行进前MARP明显更大（p  = 0.022），而防弹衣对其他结局指标没有显着影响。此外，TLS相对于TT，行走前的MARP和DP在弯曲和返回时，以及行走引起的MARP在弯曲阶段的变化明显更大（p  <0.026）。因此，立即使用防弹衣可使腰部-腰骨协调性降低，但在恢复过程中未见长效。有必要进行进一步的调查，以明确穿着防弹衣的机会增加下背部和下肢关节肌肉骨骼受伤的风险。