We sometimes need to change our understanding of strength to include yielding and gentleness. Not fighting with the reality of wind and being able to bend and go back are realities we can learn from the natural world.

Notice that the stiffest tree is most easily cracked, while the bamboo or willow survives by bending with the wind.

Bruce Lee

The tree is made strong and resilient by its grounded root system. These roots take nourishment from the ground and grow strong. Grounding also allows the tree to be resilient so that it can yield to the winds of change and not be uprooted. Springiness is the facility to ground and ‘unground’ in a rhythmical way. This buoyancy is a dynamic form of grounding.

Aggressiveness is the biological ability to be vigorous and energetic, especially when using instinct and force. In the immobility (traumatized) state, these assertive energies are inaccessible. The restoration of healthy aggression is an essential part in the recovery from trauma. 

Peter Levine, Walking the Tiger