Just what are you trying to achieve with your training? Power, strength, endurance, there are many target areas athletes train to improve their performance. The problem with many is the try to do too much in one micro- or mesocycle. A microcycle lasts about one week of a four to six week mesocycle.
There is no reason to try to target more than two or three areas per cycle. Think about some of the areas people work to train, power, maximum strength, endurance strength, speed, aerobic capacity and sport skill just to name a few. However, when you ask some people what they are trying to accomplish their answer is often all over the place, unsure or frustrated and in need of some help.
The problem with training too much at one time is performance gains decrease if several targets are trained simultaneously. Elite athletes have found the most success when they train two areas per cycle. They will train different targets over a number of micro- or mesocycles. Elite athletes train approximately 70-80% of the targeted area during a specific cycle. Some athletes struggle to plan out a year. They may scrape a plan due to impatience, the latest fad or giving in to doing too much too soon. Professional trainers or coaches clearly understand how to work the areas of performance that need time during different cycles of the year (macrocycle). They understand periodization, how to deal with endurance versus power athletes and know the value of recovery. Consider most athletes train for a single competition season each year that gives a quality trainer a great deal of time to prepare an athlete to compete at their peak.
Lastly, an athlete may believe that he or she needs to play their sport year round to reach to improve performance. Consider elite athletes do not play year round. But they do train year round (including some rest/active rest time). If the only thing you train is sport skill the chance of you getting stronger or faster is lessened. The key is to become the best athlete as well as the best player. That means training like an athlete.