Jeffrey
"Ah, well. . .It's not like I haven't tried it before. . ."
He'd pout. For some reason, it was a was common trait amongst the clan; being lackluster in the strength department I mean. Whether it was a genetic issue is undetermined. . .But it seemed likely.
~
The young blue eyed boy would chuckle as his peer corrected his form.
"Thanks, V."
He'd take a breath. Repetition, eh? *"Ughh... This is sooooo gonna hurt in the morning!*" He muttered, before pulling back his fist. 
"Let's go wall! ROUND TWO!"
He threw his punch, slamming it into the earth wall, this time causing it to chip. He wasted no time delivering his third and fourth blow, causing a visible dent. It was going to break soon.
Carter
She watches him continue to punch, noting that his form is good, even if his punches seem weak. It really is up to physical strength, then, not a lack of Taijutsu knowledge. She doesn't even consider the possibility that other people are born with genes that make it more difficult to gain muscle mass. To her, everything is about hard work, and the fact that Kats doesn't seem very strong just means he hasn't practiced strength training enough.

She continues to watch him and gives him a nod, "Keep going." She says, "You'll get there."
Jeffrey
Easier said than done y'know. . .Katsuo brought his arm back, his knuckles reddened. "Haha, that just means I'm getting closer to victory!" He'd exclaim as he looked at his red knuckles. "Here comes the final round, you stupid wall!" Activating his armor technique for safe measure, he'd once again reel back his arm before slamming his fist into the wall, and whaddya know? "I-I did it! Haha, hell yeah!" The words escaped his mouth after a brief moment of silence. He offered a fist bump but quickly retracted it, fraid his knuckles didn't need anymore stimulation for the day. He instead brought up his forearm.
"Thanks chief!"
Chief? Hey, that might stick.
Carter
V brings up her forearm as a weird version of a high five, clinks it, and puts it back down, "Hell yeah Kats!" She doesn't mind the nickname chief at all. If anything, it's welcome, it feels powerful.

"Now you gotta help me with some more questions in this medical book," She says, "An eye for an eye, right?"
Jeffrey
"Sure thing friend!"
His grin arrived once more as he gave V a pat on the back, which in turn caused him to swing his arm back, and blow on his knuckles. Shit still hurt.
"Hahaha... You ready?"
He sat down, ready to bestow his lackluster medical knowledge onto his newfound friend.