It's not as easy to say that random practice can apply to ANY sport. TT is mostly about control and variations of spin, as Volley Ball is mostly about a team effort to make the most effective transition possible between defense/receive first, and then attack in 3 phases, the 3 passes, and it's WAY MORE physical:
1- receive/blocking/digging (blocking doe not count as a pass)
But in order to get the maximum of a team effort you have to block train each individual first, the feeling and control of the ball is important there BUT also the physical aspect of it: liberos have to receive services and dig vs attacks, setters have "feel" and control the ball first and set countless of ball first, they are the creators, the blockers/attackers have to first condition themselves to endure digs, slides and vertical jumps, both standing and running jumps.
That's both physical and technical, there's way more to do than in TT. The block pratice is important there:
- serve/receive: 1 libero + 1 attackers + 1 setter, then 1 + 2 + 1, it focuses on the ability for the receivers to endure hard balls and to pass into the right setter's zone (your own 3 meters middle/right side of the pitch) FIRST
- transition to attack without blocking; with 1 attacker first first, then with 2 to force the setter to create setting variations - then 1 blocker in the opp's side: the let the attacker a chance, and then 2 blockers, to train the blockers so they can sync themselves
Then the random team practice only after that (EDIT: the individual random practice is done for only 15 minutes before the fitness conditioning: alone vs wall, and 1 vs 1).
If you don't do that block pratice first, it can lead to serious injuries, specially for the wing/hitting spiker, on the left side of the pitch, this is where you have the most complete players, like Earvin N'Gapeth or Nishida. A typical block pratice here is to receive a ball back to the net, then 180 turn you stand jump for a block, then you turn back and dig a harder attack, and so on... It's damn intense, but that's the real life in an actual game for the spikers: they spend their time either very low AND very high in the air, they do libero stuff, attacking stuff, blocking stuff, and even sometimes setter's stuff when the ball isn't passed on the middle/right side. Middle blockers, the tall guys, don't do all that things, they mostly ... block and attack on combos, they rarely receive, dig or even set.
TT is like training the setters: you have to feel the ball first, you don't have team mates to combine with so it's easier to get a good feeling and conditioning in way less time. Plus, it's not as physical, way less injuries, and way less severe ones.
I've played VB as a setter first, then libero when the new rules entered in the late 90's, then started TT... man, TT is really easier, you can't play all day long in VB, specially beach that is damn physical ! TT allows to play 3 to 4 matches a day for pros, with practices in between. And most of the time it will be random practice just to keep the sensations and control ok.