- My question is when the lumbar spine is under load the spine should be as close to neutral as possible.
Often lying on the back on the floor with for ex: legs straight, before lifting one leg at the time or both (Hip flexion) students are instructed to really press the lower back down towards the floor (lumbar flexion) before lifting the leg - to me that makes no sense [because I want] to keep the lumbar spine in neutral. Sometimes though doing that might be beneficial? What are your thoughts?
Hi Tove...your instincts are correct. Professor Stuart McGill's studies have shown that, when a spine is under significant compressive loading, it is best able to handle the load when it is as neutral as possible. For the lumbar, this means it should maintain its lordotic curve. Pressing the lower back to the floor when lying down straightens the curve which makes the spine more at risk of injury. He suggests placing both hands under the lumbar spine in this position to keep the normal, neutral curve.
When you lift the torso (ie sit ups) or the legs (leg lifts), the big back muscles and psoas will engage and they pull the vertebrae together. This creates the compressive forces that can injure the spine if the loads are too large for the spine. Keeping the lumbar neutral curve improves the stability of the lower back.
Of course, not everybody has to worry about this. Many people's spine can handle this amount of load, since they are only moving their own body weight. However, if we were weightlifting significant weight, we would be advised to make sure the spine is neutral and stiffened. But, some people have relatively weak spines (age, injury, osteoporosis, etc.) and they should do this regardless of the amount of stress being imposed. In general I would say it never hurts to keep good technique even if you are working with relatively light loads. This way, when you do get presented with a larger load you already have the best biomechanical movement patterns installed in your brain to handle the stresses.