Atmosphere we know helps in the mental part, perhaps it translates to the
neural part, too. That is, the nerves connecting brain and muscles.
One interesting thing I've learned in my course is that the nervous system is believed to hold back a lot of the muscles' capacity. When you exert force with them, they are under tension. The body fears that too much tension will tear them, so it responds by turning them off! You try to contract them more but you just can't.
This is the factor that's used to help in
PNF stretching.
You're stretched, someone pushes the limb and you push back, contracting your muscles, then relaxing them, and the muscles respond to this high tension, this stress, by relaxing more - so they can be stretched more.
Back to lifting, this is why it may happen that if given an extremely heavy load, far more than you normally lift, you don't strain yourself and tear muscles and tendons - you just collapse.
As you lift progressively more weight, your body adapts, learning that it can have X amount of tension without the muscles tearing. So it's believed that in the first months of resistance training, most of the adaptations are neural, your body learning that it doesn't have to hold back. But it's always a factor, even for people ten years training or more.
It's also believed this explains why people have been able to lift hugely more than normal in crisis situations, like the story of the woman whose son was crushed by the car he was working on, she... lifted it up and pulled him out. In time of stress, the neural holding back stops.
Obviously if you have spotters around you will feel secure in your lifts - "even if I drop it, I won't get squashed." And if you have people encouraging you, that I think can make it like a crisis situation - your body doesn't hold back so much, that enormous reserve of strength you have comes out.
None of this changes the simple fact that atmosphere and training partners and mates in lifting make a
big difference, you do much better than you would alone or with people putting you down, etc. I just find it fascinating to explore just
why...