walk into the wall

[jirickova]

Hello, I am not sure what the author means by "walk into the wall" /context: Unfortunately, many people lack stamina. They seem to “walk into a wall”. /. I am translating some promotional text of an Americal company engaged in dietary supplements. Does it mean to crash into the wall (they tried to solve the problem but they were stopped by a barrier) or to walk against the wall (they are still trying to solve the problem but their way is not the right one) or anything else?
thanks for your help
Marketa

[curmudgeon]

To walk into a wall means as you say. To come up against a barrier that they cannot get through.

[pedant]

'the wall'

This is a term which comes from athletics and other physical events - most commonly encountered when running a marathon.

Anyone who has done any sort of prolonged physical activity knows very well that at some point you totally run out of power. The feeling is awful!

In your mind, you want to keep going, but your body just can't do it anymore. You seem to just be going up and down, not along. This is exactly like what you see in cartoons where some character is running along, hits a brick wall, but keeps on running anyway, getting absolutely nowhere.

Most marathon runners hit 'the wall' at around 20 miles or so....that is about the most that a normal human can run before all reserves of energy are used up. Breaking through 'the wall' requires a great deal of mental power, and a top-up of instant energy, often supplied by a rapidly absorbed glucose drink. That is what your company is selling.