Siva, you seem to be familiar with a lot of this stuff.
We have 3-4 main energy systems. The fast energy systems like ATP/CP/glycolysis (burning sugar) are for quick actions like powerlifting or table tennis or sprinting, while the lipolysis (burning fat) is more for slow actions like sustained running. All sports have a combination, but some sports rely on one more than others.
Here's a (admittingly not perfectly accurate) analogy. For heating your house you might have an electric heater and a wood stove. For a quick burst of heat, you'd want to use the electric furnace. But it's expensive, and you run out of money quickly. For long-term heating, you would want to use the wood stove, but it takes a lot longer to light the fire and get the house warmed up. The more you use one energy system, the better you get at using that one. Someone who rarely uses wood heat will take a long time getting their wood cut, split, and get the fire started. A powerlifter, for example, who rarely does sustained activity like running will have a hard time switching to fat metabolism and producing enough sustained energy this way.
The lactate (lactic acid) thing is a byproduct of quick glucose metabolism when the activity doesn't give you time to get rid of it. When you're most used to activity where you do short bursts of energy, you get better at it and are able to deal with it better without getting tired or feeling weak.
Also, the brain controls how much neuron firing goes into the muscle, and with activity you're not used to, the brain is not very efficient in firing. This results in piles of wasted energy, which is another reason you might be able to play one sport for hours and get tired at another sport rather quickly.
In table tennis, you're mostly using that quick energy system, and between points your body gets a chance to recover and build up the ATP again so you're ready for another quick burst.
I noticed some people said earlier that Dima didn't look to be in great shape considering his level in the sport. Ever see some elite powerlifters? Some carry a significant amount of extra body fat, but they can lift weights many of us could barely roll across the floor. Dima's levels of enzymes for quick energy metabolism must be off the charts for the level he performs at. He won't be winning any marathons any time soon, but I'm willing to bet he's got an impressive sprint.
Hey are you the Bio Tech guy? I just know that lactase production in muscles lead to fatigue. Can you explain how it works?
Back in high school where we learned about Adenine Diphosphate and Kreb's cycle. Interesting to see these words in real life conversatinos