For me, training via meditation was definitely more useful than pointless beatings. Accessing energy was surprisingly easy with a power level of 160, and learning to control that raw energy was an impressively quick way to raise it. I'd definitely have to work on my physical weakness eventually, but right now, surviving took priority.
Every time I managed to find time to meditate, my power level went up by 3-5 points, which didn't seem like much, but within a month, my power level had broken 225, despite only being able to meditate once every other day.
Naturally, Asper noticed my power level fluctuating wildly, but he didn't look too deeply into it.
Then, two months passed, and my power level broke 280. In three, it was 340.
Still, Asper didn't get the hint that I was going behind his back and doing my own, personalized training. Instead, he just tried to push me harder and harder, thinking that his own 'training' was actually working.
It wasn't. It was just getting in my way, and it irritated the crap out of me.
So, I did the only thing I could think of.
I stopped growing.
More specifically, I stopped showing my growth. Meditating had granted me the ability to, to a certain extent, control my ki. As such, I began carefully suppressing my gains.
That actually helped, in some twisted way. Asper stopped expecting anything from me after two months of no gains, and I began spending every night in my bed, instead of the medical ward. That meant that, since my body had begun adapting to a lack of sleep, like a true Saiyan body, I was able to work on my energy every night. By the time I'd been out of my pod for eight months, my power level had skipped right past 500 to 610.
By then, I was four and six months, and I'd been suppressing my power level at 340 for the last three months. It was time to loosen the hold a bit.
So, I did. Over the next six months, my official power level rose by one or two points every day. By the time my fifth birthday came around, Asper was shocked to see that my official power level had jumped all the way up to 550.
Meanwhile, my real power level had jumped up to 1100, and plateaued there. In the last month, I'd only gained 20.
Still, 1100 was fine by me, for now. So long as I passed my test and earned the right to stay on Planet Vegeta, I'd gain a small bit of control over my own training schedule, and I'd be able to spend more time training in my own way.
Finally, the day of my test came along. My fifth birthday.
For the first time in fourteen months, I was allowed outside of the three rooms that had become my entire world: My bedroom, the training room, and the hospital.
I was brought out into the castle's courtyard. Despite it being in the late morning, generally the busiest time for Saiyans, the courtyard was mostly empty, save for my father and a handful of his personal guard. Naturally, my brother hadn't cared enough to show up. It didn't particularly surprise me that my father was keeping it a quiet affair. Power level of 550 or not, if I failed this test, it'd be a massive stain on the Saiyan king's honor. He wanted as few people as possible witnessing it, just in case.
"I brought the child, my king." Asper said, kneeling at my father's feet. After a moment's hesitation, I followed his example.
"Tarble." My father addressed me after a long moment of awkward silence, "I have heard that you've been making great strides in your training."
I responded with a noncommittal grunt. For where I'd started, a power level of 550 was a great stride, but my actual power level, even right now, was lower than my brother's had been when he got out of his incubator at the age of three, with zero training at all.
"We will see. Bring it out." My father nodded to one of his guards, who brought out a Saibaman.
Saibaman strength was based on where they were grown. Not just the planet's gravity, but also soil composition and a dozen other factors.
Saibamen grown on Planet Vegeta tended to have power levels fluctuating somewhere between 1500 and 2000, making my full strength nowhere near enough to beat them, but this Saibaman was different. Clearly, they'd grown him off-planet specially for me, because he felt nothing like the Saibaman that beat the crap out of me every other day. My energy sensing wasn't quite developed enough to be able to tell power levels with any sort of accuracy, but I could tell that this one was weaker than the other, which likely meant that he was somewhere less than half as strong, at least.
"Boy. This Saibaman has a power level of 500. Defeat it, and you're not worthless." My father explained.
The flip side of that coin went unsaid. If the Saibaman killed me, nobody was going to care.