The water table is the upper limit of the zone of saturation. At the zone of saturation, the aquifers are filled with water completely. The void spaces within the rock particles are taken up by fluids.
The upper limit of this zone is the water table.
Above the water table is the zone of aeration where the pore spaces are filled within air.
During the time of recharge especially raining seasons, part of the zone of aeration are filled with water.
Since your spine runs by your core, having a strong core will help protect and stabilize your spine, and you're also are able to control movements such as walking or standing better with a strong core.