Amanda cocked her head and looked at her brother, thinking of how to best break him. He looked back, not seeing his sister, he was seeing an amazingly strong and sexy woman.

"You look like you like to work out." She said finally. Robert nodded. She grinned, she knew all about the hours his friends spent lifting weights and acting tough in the basement. "Well a good workout always turns me on, why don't you show me your weights and what you can do with them."

"Sure, I have a great setup, it's..."

"Less talk more rock, c'mon big boy, show me what you got."

Robert nodded and led her to the basement. The stairs creaked under her weight which surprised her, that had never happened before. She wondered absently how much she weighed now. Robert was droning on and on about the different pieces of equipment but Amanda really wasn't paying attention. She looked at some of the pictures of male bodybuilders that were pinned around the weight rack. She had never really paid much attention to them before but now they seemed much smaller than they seemed before.

"I really don't care." She cut Robert off in mid ramble. "Lets talk about your chance ok?". She put her hands on her hips and wiggled. Robert obviously had a boner and it was creeping her out a little. She ignored it. She moved to the bench and leaned across the loaded bar, resting her breasts on the cold metal which instantly made her nipples stand out against the tight fabric of her shirt. "Lift it."

"Lift it?"

"Lift the weight Einstein, if you can't, or won't, I'm gone and so is your chance. Pretty simple."

"That's it? Sure." Robert scrambled under the bar and quickly pumped it once. "Is that it?

"For now, now it's my turn, move." She lay on the bench and gripped the bar. At first she was worried her plan might backfire but the bar felt practically weightless. She grinned and pumped it once before returning it to the rack. "All right put on more weight."

"More weight? How much?"

"I don't care, however much you want."

Robert could barely take his eyes off her exposed panties long enough to put more plate on. When he finally did Amanda quickly did a rep and reracked it. "Ok, your turn again."

"What?"

"Its your turn. To pick up the weights.". Amanda spoke slowly like he was retarded. She got up off the bench and pantomimed a bench press motion.

Robert looked at her uncertainly but did a rep with the new weight. "Now what?"

"Now I'll add more weight and go again. We keep going until you can lift a weight I can't. Then you win."

"Win what?"

"If I have to spell it out then it's not going to be worth it to let you win, now let's go. More weight."

Amanda was surprised, Robert kept up with her for almost an hour. By the end his face was turning purple and his arms shook like rubber until he finally got the weight racked. Amanda knew he was done, but she added more weight and unracked it again. This time instead of one rep she kept going. It felt good, she could feel the blood rushing to her muscles, they felt tight and powerful, like she could keep going forever. The pump was incredible. She could swear she felt her muscles growing with each rep. Small tearing sounds could be heard with each rep as her sleeves gave way around her arms and the slit in her shirt front split wider and wider. Finally she racked the weights and stood up. Her reflection in the posing mirror looked bigger than ever and she struck a double bicep pose that caused even more rips to form in her shirt. "All right sport, thats all the weight. Go for it."

"Robert tore his gaze away from her chest and eyed the bar, which was bending from the weight. "I-I don't think I can."

"You have to be kidding. You've dumped your fuckbuddy and done all this to give up now? I thought you wanted me? I'm going to be very insulted."

"I... I..." Robert looked sick to his stomach but he finally slid under the bar and put his hands on it.

"Just one rep macho man."

Robert grit his teeth and heaved upward. The weight wobbled in the rack. He grunted again and pushed with all his might. The bar rocked and wobbled and finally shook free of the rack. His arms buckled right away and he shrieked with fear and closed his eyes. After a moment where he realized he wasn't being squashed he opened them again to see Amanda standing over him. She turned, swinging her leg over the bench and straddled him. He couldn't help himself, seeing her over him like that was turning him on, he squirmed, trying to hide his erection.

"How does it feel to almost die because you're too weak?". Robert whimpered as Amanda loosened her grip on the bar and more of the weight settled onto him. "How does it feel to have a "weak" girl have to save you? It looks like you like it.". Robert shrugged and she dropped the weight further.

"Yes, yes I like it ok?"

Amanda smirked and began curling the overloaded bar. It felt so good to work these muscles, apparently she hadn't been lying when she said a good workout turned her on. Robert flinched and whimpered as the bar brushed his chin on each downstroke. She was standing just over his crotch, swaying slightly with the rhythym of the workout. She was like a machine and she seemed to have forgotten he was there. He arched his back slightly, about to rub his crothch against hers. " If you even try it I will drop this right on your face," she said without breaking her pace. Robert spent the few minutes in silent agony, fearing for his life and being painfully aroused.

Finally she racked the weight and stopped straddling him. She struck another double bicep pose that split some more seams and she grinned. "Thanks for the workout, tell your sister I stopped by. She began to walk up the stairs when he called her back.

"Wait, what's your name?"

She snorted. "Nice try loser." She flipped the lighttswitch at the top of the stairs, leaving him crying in the dark alone.

"Well that was fun," she thought when she got back to her room. She couldn't get out of the sweatshirt, after a few tries she shrugged and just ripped it off her chest. This new body was amazing, she thought as she flexed some more, the workout had definitely caused her to grow bigger. But now what?