Physical training has always been of great importance to athletes. Historically the focus was more on practice of skills, interaction between team mates/opposition and dynamic aspects that improve the actual execution of the activities. (The old school way of practicing a craft consistently over many years). This is still seen in the physical arts community for example a dancer or combat athlete’s physical conditioning without knowing how to execute the skills won’t get them far, the way one utilized energy and skill was more important than being in great shape.
Eventually this focus changed due to progresses in the field of physiology, biology, chemistry, sports science and technology
As this slowly enabled us to perfect the process of athletic development through refinement in training and analysis, the attention swayed more towards the acquisition of attributes (speed/power/energy production. physiological conditioning, breaking down the specific of the skills, movements and energy demands to make a super tuned engine and chassis for the activity or sport. It became common for athletes to seek out sport scientist and strength conditioning coaches to improve their athleticism and biological factors
Faster, Fitter, Stronger Gains
Although recently its thought that biological capacity of elite athlete population is starting to reach its peaks. While increased performance will continue to advance from: technology, collective motivation/mind-set, improved conditions, specific selection of athletes that suit certain activities and better strategies (game plans) or skills.
Coaches are now starting to bring the focus back to skill utilization practice (old school methods of mastering your craft) and general movement optimization as the high workloads and repetitions of specific conditioning given to athlete without the right readiness or lack of correct function is causing a rise in injuries along with decreasing longevity, these athletes become so specialized and conditioned at one particular task or variable, neglecting general good human function, prioritizing intense repetitive training. The price usually being a short career or problems in later life.
The human is a complex organism, simply looking at the athlete as mechanical machine gives a very small scope of view. With a deeper consideration of psychological, environment and ecological factors involved in development or performance we will continue to better the execution of sporting activity and physical development as a whole.
As these advances make their way into health and fitness/mainstream arena there is hope that general physical function, skill levels, attributes and well-being of the masses (general public not just athletes) will also improve.
David Epstein gives a great presentation of this topic in detail at TED Talks.