The afternoon passed quickly.
"All right, lunch break's over. Everybody up!"
Son Mirai jumped straight out of the hammock, while Krillin rubbed his face and woke up.
Goku stretched extravagantly, loosening up his body.
"Ah! A nap after lunch feels great!"
Master Roshi smiled. "Of course. Our bodies need to recover properly so we can train even better."
"I see! Got it!" Goku replied with a grin.
Listening to the two of them, Son Mirai pondered.
Was this what people meant by balancing work and rest, by knowing when to push and when to ease up?
Still, in his eyes, the training was far too easy. They might as well not have trained at all.
He'd only felt relaxed, not pushed very hard.
He figured he wasn't carrying enough weight, so the training wasn't improving him much—almost not at all.
"All right, this afternoon's training task is roadwork.
"It's another kind of training that both strengthens your bodies and earns you money.
"But unlike farming, you'll be able to push little carts loaded with stones. Just make sure you move fast..."
The three of them nodded in unison. "Yes!"
Master Roshi set off at a jog, and the three hurried after him.
Soon, the three of them jogged all the way to the construction site.
The jog was just a warm-up. The real work was what came next, and Master Roshi assigned each of them their tasks.
The three pushed little carts, racing down the road with them loaded full of stone.
They were so fast that they worked even more efficiently than dump trucks.
The guy operating the excavator was dumbfounded.
"They're faster than the trucks! Those young fellas sure are strong!"
Master Roshi chatted with the workers while urging the boys on.
"Move it, Krillin! Don't slack off—you're a whole cart behind."
The sun set, and that day's roadwork came to an end.
Master Roshi took the three of them to the beach.
"After working up a good sweat, it's time for swimming practice."
Krillin saw the triangular shape sticking out of the water. It was a shark fin, and cold sweat immediately broke out on him.
"Ah, we have to swim away from sharks too..."
Goku frowned a little as well. He'd already practiced this under Grandpa's guidance.
Somewhat reluctant, he said, "Master, what's the point of this?
"Just teach us real martial arts already. I want to learn some powerful moves!"
"Yeah, yeah! I want to learn moves too!" Krillin said.
Son Mirai knew Master Roshi had plenty of moves, but he wasn't teaching them any, so he kept quiet.
He knew Master Roshi must have his reasons.
Sure enough, when Master Roshi saw that Krillin and Goku both wanted to learn moves, his expression changed.
He spat on the ground. "Pah! The nerve of you, mouthing off like that!
"You can't learn real martial arts until you've built up your stamina!"
The two lowered their heads, crestfallen.
Son Mirai pointed to the Turtle Shell on his back. "Master, can I switch to a different Turtle Shell?"
Master Roshi raised an eyebrow and looked at the Turtle Shell on Son Mirai's back.
He assumed Son Mirai, like Krillin, was struggling with too much weight.
He said earnestly, "Your Turtle Shell is heavier than Krillin and Goku's, but you've got a better foundation.
"If it's too light, it won't do you any good.
"I calculated the weight of each of your Turtle Shells carefully. They're just heavy enough to push you to your current limits without injuring your bones or muscles and affecting your training later."
Hearing that, Krillin secretly felt relieved. "I knew it. His Turtle Shell is twice as heavy as mine.
"The other exercises are fine, but there's no way he'll be able to keep up in the water..."
But Son Mirai shook his head. "Master, you've got the wrong idea. I think this Turtle Shell is too light.
"I barely felt tired during today's training...
"My head was dripping with sweat while working on the road because it was hot."
"What?"
Krillin's eyes went wide.
He thought it was too light?
Krillin could already feel his shoulders starting to ache.
There really were always people stronger than you in this world.
I thought I was way ahead of everyone else because I already had martial arts training before becoming a student. I never expected him and Goku to be this strong... I can barely keep up with them myself.
Master Roshi's eyes narrowed slightly behind his sunglasses.
Son Mirai's Turtle Shell was already much heavier than normal, based on the astonishing physical abilities he'd shown at the start.
And it was only the second day, yet he already thought it was too light?
Judging by Son Mirai's expression and breathing, he was steady and even. He certainly didn't look like he was forcing himself.
If anything, he seemed... completely at ease.
This kid's physical potential and adaptability are even more incredible than I thought.
Sigh, I still underestimated him.
Master Roshi suppressed his surprise and kept his expression mostly unchanged. "Oh? You think it's too light?
"Looks like I underestimated your foundation.
"But increasing the weight isn't a small matter. The training ahead will be hard, so I need to make sure your body can really handle it."
He took the Turtle Shell off his own back.
It looked a size bigger than Son Mirai's and considerably heavier.
"Try this one!
"We're about to go swimming, and I don't recommend wearing a Turtle Shell for that.
"The human body and water are already about the same density.
"But with a Turtle Shell this heavy weighing you down in the water, you'll have to work more than ten times as hard just to swim at the same speed.
"If you can wear it and keep pace with Goku and Krillin, then swim two round trips while avoiding the sharks, I'll let you use it for training from now on."
Son Mirai thought it over. "Then I'll give it a try!"
Master Roshi nodded. "Go ahead!"
As his teacher, he wanted to get a better sense of Son Mirai's limits, too.
Son Mirai changed into the new Turtle Shell and moved around a little. "This one feels about right."
But it didn't hinder his movements at all. He was still light on his feet.
He felt as though it was no different from wearing the other Turtle Shell on land with Goku and Krillin. The water shouldn't be a problem either.
Krillin stared at Son Mirai in astonishment and swallowed hard.
Even though they were training with weights, he and Goku couldn't wear their Turtle Shells in the water yet.
Just as Master Roshi had said, the Turtle Shells were too heavy. When Krillin had secretly tried it, he'd sunk straight to the bottom.
Luckily, he hadn't gone too deep and had walked back to shore along the bottom.
Only a powerhouse like Son Mirai could swim alongside them while wearing that smaller Turtle Shell.
They'd only been training for a day, and he was already increasing the weight again?
Krillin couldn't help grumbling to himself: Son Mirai, you're way too competitive! You're making it so hard for Goku and me!
What if Master Roshi decides we've had it too easy and gives us heavier Turtle Shells too?
After fastening the new Turtle Shell, Son Mirai jumped straight into the water.
"Splash!"
Son Mirai sank straight to the bottom without a doubt.
Goku, Krillin, and Master Roshi all stared at the water's surface, barely daring to breathe.
A few seconds later, several bubbles rose to the surface, but Son Mirai didn't come up.
After a moment, Krillin scratched his head. "Why hasn't Son Mirai come back up? What if he drowns?"
It felt like he'd been under too long. Master Roshi suddenly ran toward the water and shouted, "Krillin, Goku, come help me pull him out..."
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