is a concept of inertial training based on free movements performed individually with different intensities, in which a continuous resistance develops during all phases of the exercise. The work done on the eccentric phase of the movement can improve fitness, increase strength, endurance and muscle strength, as well as help in the prevention and recovery of injuries.

The main characteristic lies in the inertial resistance. Instead of using overloads based on gravity (weight) used the inertia (resistance to change of state of motion). By applying a speed exerted on the concentric phase, we offer resistance in the eccentric phase of the exercise.

The work carried out during all phases of the exercise is quantified and displayed in real time, providing immediate feedback and being able to analyze quickly and easily. ChronoJump specific training program is a great tool for professionals. The measurement data is essential and vital for the proper development of inertial training.

As variants of inertial loads (commonly referred isoinertial), we offer: Inertial flywheels and conical pulleys. From the variability of these elements and balances of the masses, we change quickly and easily in functional resistance training, and so its variety of applications and possible progressions.

It is based on a flywheel whose axis is fixed to a support structure (inertia disc). One end of a rope transmission is wound around said axis or around a conical structure, while the other is fixed to different parts to exert traction.

Pulling the rope during the concentric action and at the end of the action, the inertial mass is rotating. It causes the winding rope and follow the practitioner must exert a resistance to slow the inertial mass and slowing it down. The angular displacement of the eccentric action is minor and causes the eccentric overload exceeds concentric.


Proinertial can be practiced by all those who want to improve their health and also is practiced by athletes to improve their records and physical performance throughout the season.

The objectives are broad:

– Area Sports and fitness: development of human capabilities and skills: cardiovascular and respiratory endurance, muscular endurance, strength, flexibility, power, speed, agility, coordination, balance and accuracy. In different scenarios and combinations of various movements, we adapted to prepare in any sport.

– Health and rehabilitation Area: injury prevention, development of bodybuilding, recovery and rehabilitation of injuries. The variety of resistors and exercises that can run, provides a high degree of adaptability to changes in the patient’s injury.

The updated versions allow Proinertial obtain a high overload on the eccentric phase of the movement as a direct feedback in real time the work done is obtained. You can hardly get safely overload the eccentric phase through traditional weight training or bodybuilding load

Since the late eighties, during long duration space travel, muscle atrophy astronauts and therefore the reduction in bone density, raised a problem, since the zero gravity environment did not allow the classic muscle conditioning.

That led to studies and research on the development of a method that did not depend on gravity (weight) and could take advantage of the mass and inertia. The result was a system for training offered resistance through a belt and a flywheel driven by a belt, generates resistance movement regardless of the force of gravity.

This resulted in the definition of movement or mechanism isoinertial*. The term derives from the words iso (same) and inertia (resistance movement), which describes the concept of offering the same inertia in both the concentric phase and eccentric phase.

* Although commonly in the sector isoinertial talking about resistance, we believe it is more prudent and correct to speak of inertial resistance.

In the inertial eccentric overload devices it allows more muscle stretch occurs. In this paper, skeletal muscle produces more stress (force) by the sum of the assets and liabilities.

By optimizing eccentric overload, exercises stretch-shortening cycle (CEA) are also included. Through these teams, the practitioner can perform explosive exercises, which favors speed and power with a single disc of inertia light or achieve high strength by adding inertia (counterweights).

The eccentric training was excluded from training programs years ago, especially those aimed at the field of health. Well, it is known that this type of work produces greater damage and muscle inflammation in relation to the concentric work (Wilmore and Costill, 2004). Now, for years and after relevant investigations and reviews conducted (mentioned Tous, 2010), this type of training is being incorporated successfully in athletic performance programs, health, prevention and rehabilitation of sports injuries. It is therefore very important valuation professional to perform this work with their athletes and patients.

Among the benefits of using inertial resistance training include:

  • controlled eccentric strengthening.
  • Increased strength and myofibrillar protein synthesis.
  • Tendinopathies rehabilitation.
  • Post-rehabilitation muscle tear preventing fibrosis.
  • Optimization in the recovery of strength after a period of physical inactivity.
  • Natural and dynamic, with unlimited variations of resistance muscle training.



The eccentric work causes further damage and muscle inflammation (Wilmore and Costill, 2004). Furthermore, this type of damage is greater when the eccentric contraction occurs at high speed (Chapman et al., 2008).

One of the great advances in strength training has been the incorporation of eccentric work most training programs (Tous, 2010). Thus, the author describes a mechanism, called Repeated bout effect, whereby the eccentric work have a protective effect at the level of connective tissue, based on a series of studies (Clarkson et al., 1992;. Friden et al, 1983 ; Hori et al., 2007; Hortobagyi et al, 1996)..

Tous indicates that after a first session eccentric exercise and after complete recovery, repeating another session of the same exercise causes minimal muscle damage Repeated bout effect. Thus the threshold of muscle rupture and increases the ability to absorb loads, producing a protective effect that makes it less vulnerable to breakage. It is therefore proposed to eccentric training as the main work in terms of injury prevention.

In the field of rehabilitation eccentric exercise has proven effective. Proof of this is that the Squat declined usually the main rehabilitation exercise in the treatment of patellar tendinopathy (Tous, 2010). (Romero-Rodriguez et al. 2011) indicate improvement in clinical and functionality of this type of work in patients diagnosed with chronic patellar tendinitis, reaching observe in response to a program of eccentric training with improved inertial technology in both muscle strength and subjective perception of pain.

The benefits of eccentric work are given by following reasons: (Soderman et al. 2001),

  • Increased strength of tendon tension.
  • Stretch effect in lengthening the muscle-tendon junction and reduced joint mobility.
  • Alteration in the perception of pain from tendon.

We believe it is not only important to make a proper rehabilitation but then must follow a job that ensures rehabilitation, first training and then competition, and eventually establish a training phase specific prevention of the injury. These phases are very important, since the previous injury is considered a risk factor for injury (Romero 2010).

Eccentric training improves the prevention and treatment of injury and also improves athletic performance.

Moreover, as there is a specificity in training adaptation to the type of contraction which trains (Higbie et al., 1996), it is logical to think that all those sports that involve careers and receptions jumps, should perform this type of training (at least at the level of fast twitch muscles, such as hamstrings).

Moreover, with the idea of ​​making specific adaptations as possible, it is logical to do this type of training demands great strength and high speed, being the most effective inertial training. The progressive implementation of protocols in strength and speed have been the safest and preventive.