First, those exercises are dangerous. Getting injured will be a major setback in your training program, and of course make the rest of your life miserable.
Second, working on an unstable surface decreases the weight you can move, so you develop less strength.
Third, balance and complex movements are very sport and activity-specific, so standing on a physio ball swinging and shaking only makes you good at standing on a physio ball swinging and shaking.
Develop mobility and stability, train fundamental movements like stepping and lifting, then build strength. Skip the circus acts.
Here's a great article on the Functional Movement Screen, I method I offer. This is the foundation of functional training.
By MIKE TIERNEY
Published: December 25, 2011
The New York Times
FLOWERY BRANCH, Ga. — When Coy Wire signed with the Atlanta Falcons in 2008, he considered himself in the vanguard regarding fitness techniques.
Wire, a linebacker, felt an instant affinity with his latest team. The Falcons’ meshing of newfangled training concepts with old-fashioned equipment broadened the scope of possibilities for the way Wire honed himself for the rigors of football.
“Every single person benefits with this,” said Wire, a modestly talented player who attributes his nine-year career, which probably ended in September when Atlanta waived him, to superb conditioning. “The players who come into the system see this is what they should be doing.”