Many parents, coaches and other audience think that kids that will advance to the high level in gymnastics should be naturally flexible, that flexibility is the most important quality of the gymnastics, that to become flexible requires a lot of effort and it is painful, that developing flexibility associated with high risks of being hurt.
Us, people, can use same words but talk about different things. In order to avoid confusion, I would like to suggest the definition, so people know what is being flexible means.
Flexibility is the ability, quality of a single muscle or muscle group to elongate, relax, stretch. Some athletes, coaches and parents are confusing flexibility with mobility.
Mobility is ability of joint /sets of joints to move through range of their motion, actively or passively. Simply speaking, flexibility is one of the parameters of mobility, that is particularly covering the ability of “muscles to stretch”.
For example, if someone deciding to work on splits, what would be the common comment? “I need to become more flexible in order to achieve full split position”. This thought wouldn't be quite right since achieving the split position depends not only on ability of hamstrings (muscles that run on the back the thigh from pelvis and below the knee joint) to relax, elongate, but also on quadriceps, hip flexors extensibility (flexibility), hip joint anatomy, hip capsule mobility, posture, balance and postural awareness. From coaches' perspective, it is important to identify what are the specifics of someone’ anatomy, body composition, muscle length etc. while teaching splits, working on flexibility and what are the goals of all of the “stretching” activities for the athletes, program they are participating in or skills they are working on.
Mistaking lack of muscle flexibility with lacking of mobility can lead to injury and reinjury of the athlete, decrease in potential progress in the program, poor ability to develop necessary skill and maintaining ability to efficiently and consistently perform the skill.
Why should we develop and focus on mobility at the young age, why flexibility is more achievable at the young age? Since the child requires efficient mobility in order to move through their daily things (kids are way more active than adults), since they learn pure motion and don’t have a chance to develop compensations (unless there is a pathology), proper approach in keeping good general mobility and adding flexibility training will ensure that nothing in the gymnasts’ body will be compromised. Also, since children have smaller muscle mass, there is less tissue to stretch, meaning the desired flexibility will achieved faster, and once achieved can be easier maintained since the child is familiar with flexibility routing and knows what the ideal end position is should be.