Throughout childhood and early adolescence, young athletes experience a time of intense cognitive and physical development. Despite the progress in overall coordination, balance and motor control that makes possible for them to learn and master some of the most complex skills at a very early age, a certain degree of discontinuity between times of intense ponderal growth – turgor from the Latin word turgere meaning increase in size, a narrow window of time between the age of 8 and 12 years old defined but an intense gain in body weight – and times of intense linear growth – proceritas from the Latin word procere meaning increase in length, a narrow window of time between the age of 12 and 15 years old defined but an intense gain in height – makes difficult for young athletes to perform at the best of their capabilities. Athletes surely grow stronger and faster but their ability to throw might no reflect the intense physical changes occurring throughout puberty.
As athletes grow taller, they eventually become faster; longer limbs allow for longer strides, covering longer distances in shorter periods of time. Longer limbs also allow for a better angle of release and more angular velocity in throwing events, However, as athletes grow taller – and they do grow taller between the age of 12 and 15 years old, whereas they do not necessarily grow stronger until after the growth spurt as suggested by a significant delay between peak height velocity (PHV) and peak weight velocity (PWV) of approximately 12-14 months – coordination, balance, and rhythm seems to temporarily deteriorate. Longer limbs and a higher center of gravity, together with the consolidation of right and left foot/hand dominance significantly affect proprioception, making difficult to perform tasks – namely, sport-specific skills, like throwing – in an efficient manner. Moreover, lack of appropriate strength – or, at the very least, lack of adequate progress in relative strength that can parallel the overall increase in speed (linear speed) and body size – makes it challenging for young athletes to experience a tangible, significant improvement in performance.
Throwing mechanics improves throughout childhood and adolescence as a consequence of higher speed of release (speed, age 9-11 years old), higher ground reaction force (strength, age 14-17), or better transfer of force “from the ground up“, a component in throwing mechanics oftentimes referred to as “separation” between hips and shoulder that involves coordination, rhythm, and balance (skill, age 9-12). To a certain extent, it is possible to understand if strength or speed is the predominant limiting factor in the development of young and adolescent athletes by measuring the difference between overweight and underweight throws compared to the average distance for a given age group. With skill being the one variables that changes to a less predictable pace, strength and speed can somehow be isolated in the attempt to define priorities in the training of beginner throwers.
By implementing proper strength training, especially throughout puberty which represents a time of high trainability for some of the most important physical attributes needed to compete in throwing events (strength and rate of force development), it is possible to overcome lack of progress in the early developmental stage of elite level atheltyes. These three simple tests can provide the necessary guidelines in the training of throwers age 9 to 17 years old: