Fitness for juniors: teenagers and training

Edited by Dr. Luca Franzon

A good fitness instructor must be able to address the needs of various types of clients. Among these are pre-adolescents and adolescents. Young athletes who may attend the weight rooms of fitness centers have special needs, as they are not yet trained on a psycho-physical level. Although fitness and weight training is not always well received by physicians and physical education teachers, if well planned and implemented it will be the foundation on which to build future athletes of various disciplines. For this to happen, the young athlete must undergo training aimed at improving both the physical and psychological profile, respecting a body that is growing and that often presents internal and external conflicts. The workouts that will be proposed to junior fitness must be varied and go to stimulate as much as possible all the conditional and coordinative skills. The importance of multilateral training is fundamental to avoid early specializations that are often seen in team sports. This process would have particularly negative consequences, because it would limit the child's potential and could favor the appearance of paramorphisms or the onset of traumatic events. Asymmetrical sports create muscular imbalances, repetitive gestures limit the formation of motor patterns and the possible overdevelopment of some parts of the body at the expense of others can create important imbalances.

The varied and multilateral stimulation, in addition to favoring the harmonious growth of all the body systems, will also prevent the boy from getting bored and losing the desire to play sports.





Correct posture

Better joint mobility

Tonicity of the muscular masses



Favorable pondo-staturale relationship

Increase of active lean mass and reduction of fat mass

Correct regulation of the diencephalic control of appetite

Correct glyco-lipid structure




Valid systolic range

Improvement of peripheral spraying (capillarization)

Facilitated venous return

Favorable blood pressure


Increased lung volumes

Rapid reduction of heart rate and respiratory rate after exertion

Increased aerobic power



Good emotional control

Good adaptability

Valid self-esteem

Good socialization skills

(Table taken from: "Evolutionary age and motor activities" by G. Caldarone and M. Giampietro - Mediserve 1997)

The word fitness encompasses a whole series of psycho-physical qualities which, when associated, ensure that the individual is physically and mentally well. Among the various components of the state of fitness, there is strength, which will be analyzed in this article. for junior users As far as strength is concerned, it is clear that according to the age of the subject the methods will change, given that the musculoskeletal, nervous and endocrine systems are constantly evolving in the young athlete.

Jablonowsky states that force:

Up to 11 years it is insignificant

From 12 to 15 years it increases considerably

From 15 to 18 it has an intense development

It follows therefore that the evolutionary period is particularly suitable for the development of strength through training. It is necessary to pay attention to the posture of the subject during the execution of the athletic gestures also because we will often be faced with subjects presenting various paramorphisms and dimorphisms. Given the possible evolution of strength development, let's classify the training in 4 steps as much as possible in accordance with the needs of the moment:

1st PERIOD between 9 and 11 years: strength will be stimulated in the form of play and without particular district specializations.
2nd PERIOD between 12 and 14 years: you begin to work in a more specific and district way, using exercises that involve the use of medicine balls, a partner, your own body weight.
3rd PERIOD between 14 and 16 years: this is the phase in which weights can be used.
4th PERIOD between 16 and 18 years: up to the age of 18 we will proceed with the training of the third period more and more specific, up to the age of 18 where the intensity can be always greater and specific.

Leaving the first two phases to those involved in training gymnastics, we move on to phase three or when a person can start attending a fitness room. Clearly, training for juniors will have to have a warm-up phase, a central phase and a cool-down phase. The first and last ones do not give problems, the central one, on the other hand, requires particular attention because it is the cornerstone of the training. The first problem that can be found is whether to use free weights or isotonic machines.This question we try to solve by presenting the advantages and disadvantages of machines and free weights summarized in the following table.



ADVANTAGES See also: machines or free weights?

  • muscle isolation
  • great security
  • reduce joint loads
  • easy to use
  • trajectories difficult to achieve with free weights
  • easy to use even for beginners.
  • Ease of loading and unloading the weight to be used

  • Greater muscle synergy
  • Greater proprioceptive solicitation
  • More coordinating
  • Lower cost
  • Less space occupied
  • Greater influence on broad kinetic chains
  • More natural movements
  • Ability to use high speeds even with low loads
  • They allow a huge range of exercises.


  • Unnatural and hardly customizable movement
  • Difficulty in being able to express high speed of execution with low loads
  • High cost and footprint
  • Not training from a coordinative and propioceptive point of view
  • Not very demanding on the stabilizer muscles
  • Usually each machine is limited to the execution of one or a few exercises

  • Greater danger than machines
  • Higher loading and unloading times
  • Greater joint overload
  • Less control in execution
  • Sometimes difficult to learn
  • In some exercises, especially with high load, they may require the presence of a partner.

According to the table I would say that if you are able to follow the subject well, free weights are the best choice for a young person, otherwise it is better, at least initially, to use machines. Once you have decided whether to use machines or weights you have to choose how to use them, in circuit or with series repetitions and recovery times. The number of repetitions, which initially must be high (14/16) to create and consolidate new motor patterns, may subsequently decrease with a consequent increase in Obviously, the number of series and repetitions will also vary according to the type of strength sought, from resistance to maximum strength.

The methods that use series and repetitions are more demanding from a physical and psychic point of view; as such they are therefore suitable for more advanced and mature subjects.

Characteristic of the circuit is the multilateral nature of the stimuli, that is, the possibility of stimulating all muscle groups with machines, weights, free body exercises and with any aerobic stations among those of toning. The circuits can therefore simultaneously give stimuli for the development of strength, for cardiorespiratory training and for weight loss (a very important requirement lately in young subjects who are often overweight). The circuit is more fun, therefore more accepted by a young person who does not have immediate specialization as a requirement.

Since the truth is somewhere in between, the Junior client should be trained with both circuits and classic set and rep exercises. The selection criterion must in any case keep in mind the degree of physical preparation of the subject, the presence or absence of postural and muscular problems, the maturity and the type of character that he demonstrates to have. The important thing is to realize that young kids can and should go to fitness centers, healthy places from all points of view, as long as the instructors are aware that a kid is not a miniature adult but a growing organism.
I conclude by stating with absolute certainty that a squat performed with adequate load and technique is healthier than kicking a ball (perhaps of unsuitable size and weight) for three hours a week, with the aim of creating small 5-year-old champions.

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