Multilateral development or General physical development
Are nonspecific exercises that contribute to athletes physical development such as:
Flexibility (if undertaken through full range of motion)
Aerobic fitness
Anaerobic Capacity
These exercises lay the foundation for further training by improving basic motor qualities and fall into two classifications:
Calisthenics: Exercises consisting of a variety of gross motor movements; often rhythmical and generally without equipment or apparatus. They are, in essence, body-weight training. They are intended to increase body strength, body fitness, and flexibility, through movements such as pulling or pushing oneself up, bending, jumping, or swinging, using only one’s body weight for resistance.
Objects: Rings, boxes, skipping ropes, medicine balls, etc.

Multilateral development versus specialization
The overall development of athletes involves striking a balance between multilateral development/general physical development and specialization. Is very important for the coach to understand the importance of each of these two training stages and how the training focus changes from the early stages of an athlete to specialization and professionalism.

Importance of multilateral development 
The use of multilateral development plan is extremely important during the early stages of an athletes development. Multilateral development during the athletes formative years lays the groundwork for later periods of more specialized training plans . Multilateral training will allow the athlete to develop the physiological and psychological basis needed to maximize performance later in his career.

What if early specialization occurs ?
Based on scientific studies athletes who specialized at a much earlier age tent to have a very quick performance improvement and fast adaptation at the early age of 15 to 16 with a peak and plateau on their performance at the age of 18, which is most of the time followed by a burnout, increased risk of injury and quitting the sport.

The benefits of multilateral development
With multilateral development the athletes will have slower performance improvement with their best performance at the age of 18 and above when the athlete has reached physiological and psychological maturation. Consistency and progression in competition performances will be the result of these maturity, with a promising and longer career with less injuries.