The girl sat there in a daze, her breasts half-wrapped, her temples slightly damp, her breath seemed to have a rich fragrance like Lan Rui, and her jade-like skin was covered with a layer of snow-white luster. body

Chen Ya watched it blankly for a long time, and his mind was full of messy things such as "thin ice and thin skin, snow greasy and crispy in one hand".

"Have you seen enough?" The girl's cold words pulled Chen Ya back to reality in an instant.

"Ah, I'm sorry."

Chen Ya turned his back and asked with concern, "Who are you tied up here by?" Do you want to call the police? Where's your clothes?"

This sentence did not provoke any response like a mud cow entering the sea, Chen Ya waited for a long time and turned around, but saw that the girl's face was flushed and her fists were clenched, as if she was sulking.

"Turn around!"

Chen Ya hurriedly turned his head, and after a while, the girl behind him seemed to be in a good mood. body

"I'm not tied here, I'm here myself."

Chen Ya's eyes narrowed: "You said you tied yourself up?"

"No, I didn't tie myself up, I was ......."

"Are you?" Chen Ya asked tentatively.

"I'm sleeping."

「……」

The two were silent for a while, and then Chen Ya turned around gently and whispered: Bow

"If you're coerced, blink and I'll find a way to get you out of the hurricane."

"I don't!"

……

It took Chen Ya a while to figure out that this girl named Lu Aiai was actually just sleeping here.

"So you're sleeping, I thought you were kidnapped." Chen Ya smiled, "Then why don't you remind me?"

At this time, Lu Aiai was already dressed. Inside is a simple white shirt, the lower half of the body is black skinny jeans, and the outside is covered with a white coat that I don't know where I got it.

However, her figure itself is very good, and after wearing a loose white coat, she looks more charming, with a feeling of being slender and thin. body

"I—I...... That kind of thing is in the past, and I don't mind anymore," Lu Aiai replied, "So, which department are you a student in?" Why haven't I seen you?"

Chen Ya smiled and said vaguely: "I hang out in school every day, haven't you seen me, junior sister? Maybe you don't go out much."

"School Girl ......"

Hearing this title, Lu Aiai's face flushed with a slight flush again. Chen Ya found that this girl blushed easily.

Chen Ya didn't want to reveal that he was actually not a student of Beijing University so quickly, with the identity of a student, it was always easier to do things, if he told the other party that he was just a former librarian, maybe he wouldn't borrow it.

It's just right that Lu Aiai doesn't know him - in Chen Ya's eyes, this Lu Aiai is probably a student who doesn't like to study much.

After all, everyone who has been to the library should know themselves. body

Lu Aiai looked at him with her hands on her hips and a suspicious face, and said, "Then what are you here for?"

"Oh, I want to visit our school's tennis club," Chen Ya made a gesture of swinging a racket, "I want to come and practice tennis every night from today to the next month."

When he said this, he tried to make his expression hard and serious, and there was a slight smile on the corner of his mouth - from experience, this kind of expression is very lethal to girls.

However, Lu Aiai kept staring at him suspiciously, and her expression did not change at all.

Chen Ya's scheming just now was like a flattering eye thrown to a blind man.

"You want to play tennis, don't you? Okay, the mentality is not bad," Lu Aiai nodded, "However, classmate, the way you speak is going to change, how do you think about it, how convenient it is for others?" In the future, if you use this way of speaking in society, you will hit a wall."

"......" bow

This girl obviously looks younger than herself, she didn't go out of the university gate, but she spoke in an old-fashioned manner.

Chen Ya felt that he was actually trained by her

What happened at the meeting was very funny.

"But it's not that you don't agree, the tennis club is closed today, there is no one at night, if you want to use the court, you can use it, and if you want to come in the future, you have to do it after 9 o'clock every day, because everyone usually trains very actively."

Chen Ya thanked him and asked, "Are you the president of the tennis club?"

"It's not...... However, what I say, you can assume that the tennis club agrees." Lu Aiai brushed her face and combed her hair, "The lights on the tennis court are off at 10 o'clock, please hurry up."

Because there is no one else, no one can practice with Chen Ya, and Chen Ya can only practice serving by himself.

I played with a few balls in my hand for a while, and I had to pick up the ball from time to time, which was not very efficient. Lu Aiai kept holding her arms and watched him from the sidelines of the court, yawning from time to time. body

He wanted to open his mouth to ask Lu Aiai if the tennis club had a ball machine, but seeing that Lu Aiai was very uninterested in herself, and there had been such an embarrassing occasion before, she was a little embarrassed to ask her.

After playing a few balls like this, Lu Aiai on the side suddenly spoke.

"Have you ever played tennis before?"

Chen Ya stopped his racket and said, "No, today is my first contact with tennis."

"Your serve is pretty standard, it's just a little awkward." Lu Aiai commented, "Actually, your movements can be more crisp and neat, because you are a boy with more strength, and your current movements are a bit like a girl."

「……」

The reason why Chen Ya's serving action is like that of a girl, of course, is because he has only seen Gu Yuqing play. body

"Crisp and neat, do you want to swing like this?" Chen Ya asked, "Do this and swing the racket?"

He demonstrated a few movements, and Lu Aiai frowned and said:

"From a fluid mechanics and anatomical point of view, if you want tennis to reach its highest initial velocity, you need to exert your brachioradialis, deltoid and pectoralis major muscles.

Chen Ya was a little stunned, if he didn't have any knowledge reserves, he wouldn't understand what Lu Aiai was saying.

He tentatively moved his right arm, felt the muscle groups that Lu Aiai said, and seemed to understand what she meant.

Although what Lu Aiai said was very useful, her way of expressing it was a little unpleasant.

Chen Ya also said in a professional tone: Bow

"I've seen a tennis player who uses wrist muscles, core muscles, and lower limb muscles when she serves, is that the way it works, it's more efficient?"

After listening to Chen Ya's words, Lu Aiai did not have an impressive expression as Chen Ya thought.

Instead, she let out a long sigh and pressed the bridge of her nose and eyebrows, as if she was helpless.

"Previously, I did an experiment on the muscles used in the tennis's strong serve, told the subjects in advance the landing range of the strong serve, and used the American wireless DELSYS surface myoelectric to collect the surface myoelectric signals during the serving process, and synchronized two high-speed cameras to record the action screen and the landing point of the serve respectively, and measured the ball speed at the same time. The analysis action is to select the inside corner, middle corner and outside corner with the highest ball speed, and the three ball speeds are the same, where the analysis phase is the hitting phase, and the hitting phase is from the beginning of "scratching the back" to the end of hitting the ball. The analysis index was the root mean square amplitude value, and the one-way variance analysis in SPSS software was used to analyze the difference between the muscle force characteristics in the hitting phase of the three landing points, P<0.05 indicated that it was significant, P<0.01 indicates very significant...... In the end, it was concluded that there was no significant difference in the amount of power between the other muscles involved in the player's strong serve at different landing points."

Chen Ya was stunned by Lu Aiai for a while, and when he heard half of it, his thoughts began to slip.

"I'm sorry, can you make it clear in a concise way what the conclusion is?"

"Didn't I just say that?" "There is no significant difference in the amount of power between the other related muscles of the powerful serve at different landing points, which means that the main thing that determines the landing point of your ball is the three groups of muscle groups I just mentioned." body

She felt very dedicated

As the industry looked, Chen Ya asked modestly, "Then, how should I exert my strength to be the most standard?"

Lu Aiai frowned and thought for a while, and said, "You are the first time to contact tennis, and I originally wanted to let you intuitively feel this sport first, form a simple cognition, and then study it in depth, which is also in line with the general laws of understanding things, but ......

"But?"

"But you're the first person in so many years to listen to what I just said and have the curiosity to talk to me, so *** just tell you how to exercise in scientific language."

For a moment, Chen Ya suddenly felt that this girl was a little pitiful.

She's the kind of person who is a science maniac.

Still, he could understand the feelings of her classmates. body

Lu Aiai said: "The vigorous serving action of tennis is explosive force, which basically follows the principle of giving priority to the large muscles, and the size of muscle mobilization in the power chain is different, but the large joints are always mobilized first. Under certain circumstances, the size of the muscles recruited by each muscle can reflect the amount of force used by the human body during the hitting process.................. Therefore, when serving a strong serve with different landing points, the basic movements are the same, and the power is transmitted from the bottom up and the final "whipping" action, but the specific mechanism needs to be further studied."

After saying many words in one breath, Lu Aiai's mouth was a little thirsty, but she still asked with concern, "Do you understand?"

"I'm about halfway there, but you don't have to go any further."

Lu Aiai was not annoyed when she heard this, but nodded solemnly and said, "If you can understand half of it, you can be regarded as having a very good understanding, much better than those other students in the tennis club."

"Well, have you ever thought about it, maybe it's not their comprehension, it's ...... Uh, the problem with your expression?"

"What did you say?"

"Nothing." body

Chen Ya thought back to Gu Yuqing's actions, and corroborated each other with the "highly theoretical things" that Lu Aiai said, and suddenly had a clear understanding.

Gu Yuqing's physical fitness is different from his physical fitness.

Gu Yuqing's strength is much smaller than his, and there is still a lot of burden on her chest, so her movements are definitely not the most optimized movements.

If you want to play tennis well, of course, you can't copy Gu Yuqing's movements to yourself as they are, but you need to optimize them according to your physical conditions.

After thinking about this layer, Chen Ya silently raised the racket.

"Bang!"

The tennis ball was knocked away with great force, and in the next second, it had already appeared in the net at the end of the opposite court. body

Chen Ya walked over, stretched out his fingers, and used a lot of strength to pull out the tennis ball that had sunk deep into the barbed wire.

If it weren't for the barbed wire fence around the stadium, he wouldn't know where his ball would fly.

On the side, there was Lu Aiai's applause.

"Wonderful. You actually applied the theory into practice so quickly, and according to my rough visual observation, your hitting efficiency has increased by 12%~19%."

Chen Ya looked back and smiled, "Thank you, are you interested in playing a game with me?"

"Huh?" Lu Aiai had a question-asked expression on her face.

"Your theoretical foundation is so strong, and you must be very strong in actual combat, right? The theory I used just now was limited to the serve, but tennis is not such a simple game, and there will definitely be various situations in reality, so I think it would be better to keep improving the theory in practice." body

Lu Aiai nodded solemnly: "You have a bit of truth in what you said, I didn't think about this before."

"Haven't you thought about it......

"Okay, I can play you a game." Lu Aiai finally nodded in agreement.

Both of them stood in half the court with rackets in their hands, and Lu Aiai took off her white coat, revealing her curvaceous figure inside.

Of course, the peak of its curve is far worse than Gu Yuqing's, especially the curve of the specific point, which is too far away, and it is not an exaggeration to say that it is a barren resource. The grace of its curves, the Lord

If it is a waist and long legs.

Chen Ya takes the ball and serves.

Before serving, he asked, "Let me ask you, how is your tennis level?" body

Lu Aiai said, "Why are you asking this? You think I'm a nerd and can't play, do you?"

"I didn't mean that, I mean, if you're at a high level, I'm going to give it my all."

"Hehe, you go all out." Lu Aiai sneered, "If a novice like you fights me, I'm afraid others will say that I am a bully."

Chen Ya is not worried about being bullied. Anyway, I've been bullied once today.

After being hit by Gu Yuqing like that once, and being able to turn the tables in adversity, Chen Ya felt that no one could break him mentally.

"Bang!"

Chen Ya twitched the tennis ball vigorously, and this ball, cutting through the sky, tearing the air, spun rapidly, and flew towards the half area under Lu Aiai's feet. body

This is the serving rule of tennis, when serving, the tennis ball must land in the designated half of the area, which is an area that is not too large for a novice, and it will go out of bounds if you are not careful.

Lu Aiai held the card with both hands, like a Japanese samurai, running with her legs and rushing forward bravely, fiercely rushing towards the small tennis ball!

The tennis ball swept through the air, and Aiai's racket – because she was completely misplaced – struck her straight in the forehead.

"Quack!"

Lu Aiai let out a strange scream and fell, and the murderer fled the scene with a tennis ball.

"Smack."

The racket in Chen Ya's hand was thrown to the ground in horror. body

"How are you? Road love love! Are you alright?"

He ran to Lu Aiai's side and hugged the girl's shoulders and lifted her up.

"I didn't...... day." She said with her tongue wide open.

"You still say it's okay, both of your eyes are cross-eyed."

"I'm so dizzy......

"I'll take you to the hospital right away!"

Chen Ya carried Lu Aiai on his back, wrapped his hands around her thighs, trotted all the way, and rushed to the school hospital. body