If the spine maintains a normal S-shaped curve, the impact received from walking is dispersed throughout the body.

If the spine maintains a normal S-shaped curve, the impact received from walking is dispersed throughout the body. However, when the back becomes flat, the impact and body weight are not distributed properly. Without proper distribution, there's an increased risk of premature wear and tear on the intervertebral discs.

Additionally, forces pushing the intervertebral discs backward can lead to conditions such as disc herniation, shoulder stiffness, and lower back pain. Herniation can compress nerves in the lower extremities, leading to numbness and pain in the thighs, lower legs, and buttocks.

When the pelvis tilts and one cannot sit deeply in a chair, poor posture can develop. This may cause more back pain when seated compared to standing. As a result, pain and numbness may also occur in areas from the lower back to the neck and shoulders.

The main three causes of a flat back include:

1. Prolonged sitting:

   
   

   Sitting in the same position for extended periods, such as during desk work, can increase the likelihood of a flat back. Even if one sits deeply in a chair, the buttocks gradually protrude forward until the sacrum contacts the seat, leading to loss of the lumbar curve.

   
   

2. Muscle stiffness from exercise: Muscle stiffness can result from:

   • Fatigue and tension in muscles after vigorous exercise, reducing flexibility.
   • Muscles atrophy and joints stiffen due to prolonged inactivity.
   • Injuries or illnesses causing damage to joints, ligaments, etc., leading to tissue stiffness.

   Due to these factors, the gluteal muscles (gluteus maximus) and muscles at the back of the thighs (hamstrings) may become excessively stiff. This causes muscles to pull the pelvis, leading to its backward tilt and decreased lumbar lordosis.

3. Habitual forward bending: Prolonged use of smartphones, for example, can lead to habitual forward bending. This posture can cause a rounded back, resulting in stiffness or pain in the shoulders, neck, and even numbness in the hands.

如果脊椎保持正常的S形状，走路时从地面传来的冲击会分散到全身。然而，如果背部变平，冲击和身体重量就无法分散。若无法分散，椎间盘磨损的风险会增加。

此外，施加在椎间盘后方的力量会导致椎间盘突出、肩颈疼痛和腰痛等问题。椎间盘突出会压迫脚部神经根，可能引起大腿、小腿和臀部的麻木和疼痛等症状。

如果骨盆倾斜，无法深入椅子坐下，姿势就会变差。在坐姿时可能感觉到比站姿时更多的腰痛。这会导致腰部到颈部和肩部等地方出现疼痛和麻木。

导致背部变平的主要三个原因

背部变平的原因主要与日常生活习惯有关。让我们一一看看这些习惯如何影响。

⭐️长时间坐着

长时间保持相同的坐姿，比如办公桌工作，会增加背部变平的可能性。即使深坐在椅子上，臀部也会逐渐向前突出，直到骶骨与座位接触，形成骶骨座位的姿势，使腰部曲线消失。

骶骨座位看起来是一种舒适的坐姿，但实际上会对腰部和背部造成很大的压力。坐在椅子上时，应注意将坐骨完全放在座位上。

⭐️运动使肌肉变硬

肌肉变硬的原因主要可分为以下三类：

• 激烈运动后，由于肌肉疲劳和紧张，柔韧性降低
• 长时间不活动导致肌肉萎缩，关节也变得僵硬
• 受伤或疾病等导致关节和韧带受损，后遗症导致组织变硬

由于以上原因，臀部肌肉（臀大肌）和大腿后侧肌肉（腘绳肌）可能过于紧张。这会导致肌肉拉扯骨盆，使骨盆向后倾斜，腰椎前凸减少。

⭐️长时间低头

长时间使用智能手机等会导致习惯性低头。在这种情况下，可能养成低头的姿势，一旦固定，就会导致背部变平。

背部变平会导致肩膀和颈部感到僵硬或疼痛，甚至引起手部麻木。