[Paper Keywords] Youth football athletes speed strength training．

【Paper Abstract】Speed ​​power is a comprehensive expression of speed and strength, and its improvement is restricted by speed quality and strength quality. Strength and speed are the determining factors of young football players' quickness. The ~,-fd expressions of speed power are explosive power, starting power, and reaction power. The sensitive period and necessity of the development of strength and quality of young football players are put forward, and the theory and practice of speed strength are summarized.

Since the advent of "comprehensive" football in the 1970s, football players' physical fitness has received increasing attention. Especially in the 16th World Cup in 1998, one-on-one confrontations between players from both sides became increasingly frequent and intense. Confrontation always runs through the entire process of the game, and most technical actions are completed at a fast pace or with explosive force, which shows that the speed and power of football players play an important decisive role in the game. In the 1970s, Perene believed that :'.Speed ​​strength is of great value to football players, and speed strength is highly correlated with 50-meter sprint and jumping ability." A large number of Oberg's studies in the 1980s also further showed: "Speed ​​strength plays an important role in high-level and low-level football players. There is a significant difference between them." At the same time, research results on speed, strength and technical ability show that long-distance shooting and long passing are not only related to technical level, but also closely related to the rapid flexion and extension of knee muscles. Due to football matches It is difficult to count the explosive movements with and without the ball. Speed ​​and strength have become one of the main indicators for evaluating high-level football players

To this end, exploring the theory and practice of speed and strength training for young football players is of great significance to improving the competitive level of young football players. This article briefly summarizes the theoretical research and practical application of speed and strength training for young football players in recent years. , for teaching and training reference

　1 About the "core" of speed force f

Speed ​​power, also known as quick power, refers to the maximum movement speed displayed by football players in the shortest time under specific load conditions. This speed of movement generally refers to the ability to exert muscle power in the shortest time. .Strength is a form of human movement skills, which is the ability of the human body or a certain part of the body to overcome resistance when muscles contract and relax. Previous research results have proven that speed strength is a comprehensive expression of speed and strength, and its improvementRestricted by speed quality and strength quality (Kuznetsov, 1973; Dobrev, 1983). Physiological studies have proven that the degree of muscle shortening during contraction is related to speed and load. The greater the load, the smaller the muscle shortening. , and the speed is slower; when the load is zero, the speed is maximum; when the load reaches the point where the muscles just cannot bear it, the speed becomes zero, thus producing the maximum isometric contraction tension. Therefore, only by improving both speed and maximum strength , can the movement speed be improved under various external loads. However, training practice has proved that it is more difficult to increase speed, but easier to increase strength. Therefore, strength development exercises are the main way to improve speed and strength. .

The decisive factor of speed and strength is the speed of muscle contraction. Most technical movements are completed at a fast pace or with explosive force. Such as the speed of throw-in, the speed of leg swing when kicking, etc. The starting speed below is an outstanding manifestation of speed power. Typical manifestations of speed power mainly include: explosive power, starting force, reaction force, etc.

　2 Sensitive Periods Regarding the Development of Strength and Quality of Young Football Players

The sensitive period for the development of strength and quality of young football players is from 13 to 17 years old. Maximum strength enters the first peak of rapid growth from 13 to 17 years old. The growth of strength in this age group is synchronized with the growth of weight, and the maximum strength Growth is fast, but the relative strength does not increase much. At this time, the length of the muscle grows faster than the width growth, because this is also the period of rapid growth of height. 16-17 years old is the second peak of rapid growth of maximum strength. At this time, the speed of muscle growth in the transverse direction is accelerated. The maximum strength and relative strength are both growing rapidly, which is the most important period for developing strength quality. From 18 to 25 years old, strength growth becomes slow. After that, if you do not persist in exercising, your strength will increase. As age increases, strength will gradually decrease. However, if good training is maintained, men's strength can increase up to about 35 years old. As for the "sensitive period" of speed strength, it is earlier, between 7 and 15 years old for men and between 7 and 15 years old for women. Development is faster at the age of 13, which is closely related to the early "sensitive period" of speed quality. In summary, the growth of adolescent strength has the following characteristics: rapid strength precedes maximum strength; maximum strength precedes relative strength; length muscle strength increases It precedes the transverse muscle strength; the trunk muscle strength precedes the limb muscle strength.

However, the current training status of young football players in our country is: focusing on technical teaching and practice, ignoring physical training in various sensitive periods, especially speed and strength training, which plays a decisive role in football matches. From this point of view , while young football players are practicing early technical skills, they should carry out rapid strength exercises scientifically, systematically and effectively to lay a good foundation for future development.

3 About the training of young football players to exert their strength

Explosive power refers to the ability to overcome a certain resistance with the shortest time and maximum acceleration. The size of explosive power is determined by the coordinated force of all muscle groups participating in the activity. The improvement of explosive power depends on the development of the maximum strength level. If If the maximum strength is not developed enough, the explosive power cannot reach a high level, so the training methods for developing maximum strength are also suitable for developing explosive power.

Schroeder believes that the main feature of explosive training is that the main stimulus used in training is closely related to the type of completed movements and the amount of force exerted. Therefore, the main stimulus of power training is acceleration. The main methods for developing explosive power include rapid force training and super isometric exercises.

3.1 Quick force method. The characteristic of the fast force method is to use the fastest contraction speed to overcome a certain weight of the equipment to develop the explosive power of young football players. It includes the following two forms: (1) Medium-intensity rapid force method, which is characterized by using 70% to 85% intensity and practicing 4-6 groups at the fastest speed, with each group repeated 3-6 times. This method is extremely effective in improving muscle strength. This is especially true when using snatch, clean and jerk or high grab, high clean and other forms to develop explosive power. In addition, you can also arrange exercises that have a smaller load but can be completed quickly, such as medicine ball throwing exercises. (2) Small-intensity rapid force method, which is characterized by using 30% to 60% intensity. Practice 3-6 groups of 5-10 times each, perform specialized development exercises, and make the structure and muscle working methods of the exercises as close as possible to the competition movements. The principle behind the rapid force technique is that an increase in speed is a sign of an increase in strength. The rapid force method is conducive to cultivating young football players' speed awareness and the spread of fast movement reflexes.

3.2 Super equal length exercise method. The super isometric training method is also called the super long training method. It is actually a training method that combines concession exercises and restraint exercises. During super isometric exercises, the muscles first make concessions and are extremely stretched, and then switch to restraint work as quickly as possible. The purpose of the exercise is to transform pure strength into explosive power. The physiological mechanism is the stretch reflex, that is, when the muscles give way to work, the muscles are stretched beyond their natural length, causing the stretch reflex, thereby producing a more powerful restrained contraction. To effectively develop explosive power.

The methods and content of super isometric exercises to develop explosive power mainly include: deep jump exercises and various jumping exercises, such as vertical jumps at maximum speed, frog jumps, continuous step jumps, hurdle jumps, and multi-level jumps. , jump up, jump down, box jump and other exercises. The content, number of groups and times of super isometric exercises can be selected according to training requirements and each person's specific situation.

4 Training on motivation of young football players

Using the muscle power of the lower limbs as quickly as possible in the shortest time is called starting force. Sports practice proves: the maximum strength is the starting forceBasically, many power football players, despite their heavy weight, have not engaged in specialized sprint training. But their starting speed is very good. There are many ways to develop motivation. The following exercises have a positive effect on developing motivation: various sprint exercises using terrain and features, running on sand, going up (down) slopes, running stairs, etc.; using equipment and instruments. Various running exercises. Starting acceleration with a weighted vest, acceleration running with sudden change of direction, timed sprint, acceleration running with a lead belt, weight-bearing barbell running, etc.; acceleration running with various resistances (assist) from companions, traction running, and starting changes at the signal. Prepare to run and wait. In addition, super isometric exercises to develop jumping reflexes, such as deep jumps and various jumping exercises, are also effective means of developing starting power.

5 Regarding the training of reaction ability of young football players.

Reaction force refers to the ability of a moving human body to brake quickly and move in the opposite direction with high acceleration. When the human body moves, the muscle chain brakes the human body's movement speed, causing the stretch reflex. During the disengagement phase of braking, the active muscles are lengthened; during the concentric phase of acceleration, the muscles contract and shorten rapidly. Therefore, the reactive contraction pattern is a highly active form of muscle lengthening-contraction cycle.

The reaction force mainly includes the bounce reaction force, which is mainly about jumping, and the hitting reaction force, which is mainly about hitting, whipping and kicking. The difference between these two forms of contraction lies in the different stimulation relationships. In the typical reaction form of deep jump, the muscles are lengthened because the body that is braking downward is forced to perform by gravity. People are accustomed to calling it super isometric exercises. On the contrary, in the typical reaction form of hitting, the muscle lengthening is caused by the resistance force. This kind of stretched muscle is not active. Therefore, the lengthening-contraction cycle is much slower than that of deep jumping. ．

5.1 Training of jumping reaction force. The method of developing jumping reflexes mainly adopts the super isometric training method. The training content mainly includes two aspects: (1) Deep jump practice, with a falling height of 40-70an. If you use a lower height, you can develop maximum speed; if you use a higher height, you can develop maximum power. It is required to get up immediately after jumping and try to jump as high as possible. This kind of exercise can be arranged twice a week, with 4 groups each time. (2) Various jumping exercises, use maximum speed to do multiple vertical jumps, step jumps, multi-level jumps, continuous jumps with weights, one-legged jumps, multi-level frog jumps, continuous jumps over low hurdles, and continuous jumps. Steps, jumping up and down, etc. In addition, British youth football players mostly use light dumbbells to squat and jump, shoulder barbells to squat and jump, weight-bearing split jumps, fast, weight-bearing heel raises and other exercises to develop their jumping reflexes.

5-2 Training of hitting reaction. The main technical action in football is kicking the ball. Developing hitting reflexes, especially the strength of the antagonistic muscles, is an important task in the training of these technical actions. There are mainly the following training methods: (1) Compromise exercise method, that is, eccentric contraction, to develop antagonistic muscle strengthquantity. (2) Imitative practice method, mainly developing antagonistic muscles and hitting speed. You can use a light barbell to quickly jump and push flat to develop the speed and strength of the body. When practicing, you should pay attention to the range of the movement, the lengthening movement before completing the movement, and the muscle tension that is sufficient to cause whiplash. Depending on the selected load and the athlete's training status, the exercises generally do not exceed 5-8 times per group.