Carrying a heavy load that is unevenly or improperly distributed can result in poor posture and even distort your spinal column. This impact can throw your spine out of alignment, causing muscle strain, headaches, back, neck, arm pain, and even nerve damage. More than 50 per cent of young people experience at least one episode of low back pain by their teenage years. Research indicates one cause is improper use of backpacks. So, pack it…