When those doors opened, and Jayne saw her standing there, atop a mountain of Reaver corpses, splattered in their rank blood, he was awed. Then he grew jealous that so much killing skill was packaged into the delicate girl, and that his merc ass had been scared shitless, and that he would never be able to mow down that many Reavers in a whole lifetime. Then he thought "Gorram, that girl's someat different, and maybe she ain't just a crazy kid."
He was taking a lot more notice of the moon-brained girl than normal. He noticed the way her calves flexed as she walked and danced 'round the ship, he noticed the different degrees of vacancy her eyes expressed, he noticed the way she held her chopsticks at meals. But noticing and interacting with the girl were different things, and what Jayne wanted more than anything was to fight with or learn how to fight from River.
He was liftin', when she walked in. Her head was tilted at that funny angle that meant she was concentrating on some'at important. She sat on a crate, her head still tilted, staring at him as he pushed the bar away from and lowered it back to his chest. Why'd she have ta stare at him like that, made him feel she was lookin at him as a group of numbers, without skin, calculating. Still 'haps he could get her to fight him, they'd have a sparring session whens he'd finished liftin. He fully extended his arms and resettled the bar in it's holder. He sat up.
"Abduction of the triceps brachii, pulls the olecranon process of the ulna, pushing the weighted bar away from Jayne," she said her head now held straight up, "Abduction of the biceps brachii, has the adverse reaction, force pulling on the tuberosity of the radius retracts the bar to Jayne's torso." Jayne gave her a blank look, he'd only understood three words of River's observation. "Muscles," River said sounding somewhat put out, as if she'd expected anyone to understand what an "oh-ley-crayon" was. She stood up and walked over to him, "triceps brachii" she ran a forefinger down the back of his arm.
"Whatchya doin? Oh, ya mean that's what that muscle is called?"
"Ape-man comprehends. Good. Olecranon process," River prodded the point of his elbow, "Biceps brachii" she ran her finger down the thick muscle in the front of his arm and ended in the crook of his elbow.
"So's those muscles what I use ta bench. What 'bout punching?"
"All. Power flows through, from toes to fingers. Main though, biceps, triceps again, deltoid, teres major, serratus anterior, and palmaris longus." Once again her fingers skimmed over his arm as she listed the muscles. When she reached Palmaris longus, she gripped his hand and took a step back forcing him to stand up. "Punch."
"What?"
"Punch, towards me." She took a couple steps back to give him room.
"I don't know girl, I could hurt ya," Jayne hesitated.
"I can hurt you more. Now punch," she commanded. So he did. She caught it in the palm of her hand, stepped back still holding her hand up, "palmar and dorsal interposes, brevis, trans, and obliquus pollicis, abductor, flexor brevis, and opponens minimi digiti," she listed again pointing to each, 'cept her hand was so small looked ta Jayne like she was only moving her finger in a circle round her palm, no definition between the position of each muscle she said. "Kick." His foot came towards her chest but was blocked by her forearm. "Rectus femoris, vastus medialis, vastus lateralis, satorius, anterior tibialis, extensor digitum longus," she took a step back and held up the arm that had blocked his kick, "bones: radius, ulna," she pointed to each side of her forearm. She smiled up at him, a sweet-little-girl-having-fun smile. He smiled back, a merc-having-fun-without-a-gun smile.
"Can we keep goin'?" he asked.
"Keep fighting if you wish to continue instruction," River replied with a nod.
They moved 'round the cargo bay. Jayne throwing powerful punches and jaw-breaking kicks that River blocked and avoided with ease. She danced 'round him throwing her small fists and anatomical names into the air. River jumped onto and over crates, while Jayne grounded himself in the open middle of the bay. River would sweep in close to the ape-man testing him, calculating his reach and speed. Jayne was having trouble just keeping' the girl in his sight, she'd rush up to him then jump out of the way to avoid his hit, and appear on the other side of the room. Even in the oversized boots she wore, River hardly made a sound. He spun to find her again, but too late the girl was behind him jabbing her elbow into the small of his back, "thoracolumbar fascia" he heard her say before she was gone again, disappearing behind the parked mule. Jayne's feet grated against the metal floor of the hull, alerting River to all of him movements. Though, she probably knew what he was gonna do 'fore he did, gorram reader. River moved into his range again, and seeing what he thought was an opening Jayne punched towards River's shoulder, but the reader ducked under it and her fist connected with his side "latissimus dorsi" she spun away as he turned to face her. She moved in close, faster than he'd expected, and swept a foot behind his knees "gastrocnemius" he fell to the bay floor, catching himself on a hand, but River was on him, one knee pinning his shoulder, while the other pinned his opposite hand, and her hand was 'round his throat "sternocleidomastoid, sternohyoid," she said a happy look of triumph on her face.
"'Kay you win girl. Hows bout you let me up?" he asked feeling her hand against his neck as he spoke. She smiled again, the eyes fixed on his were clear, sane-like, she was actually here on the ship with him, instead of half a galaxy away.
"I enjoyed our instruction, it was effective exercise," she said standing up.
"Yeah, me too," Jayne replied pulling himself up off the floor, "You're a better fighter than me girl; an' I'd like ta get good enough ta land a hit, any chance we could do that again? "
"Repetition is an effective teaching method. Thursday at noon, ship noon, no time in the black, here, we will continue mechanical instruction of anatomy," she said giving him one last smile before climbing the stairs up to the kitchen.