Many athletes I encounter think there is a magic bullet. They believe that if they work really hard, almost kill themselves in training and aim for their best average watts every workout, their goals will be realized. It's just not so.  I remember telling one of my coaches years ago, "for this race, I am going to give 110%. You watch! I'm done with clowning around. I'm giving MORE than I have." He laughed at me. "Ok, Chrissy. Good luck with that cuz you only have 100%. There is no such thing as 110%." In single sports, it is easier to see what sessions affect others positively or negatively. High volume, intensity and load will eventually lead to fatigue. Typically you can build more load into an athlete in one sport since their energy isn't being reserved for anything else (other than life of course). In multi sports, we have competing disciplines demanding energy in completely different recruitment patterns thus becoming less clear what sessions affect others. Through trial and error, experience, some research studies, historical data, physiology and athlete feedback, we get a fairly good sense of how much one athlete can handle vs the next. The one theme that is repeated time and again by olympians, elites, and high level amateurs is that consistent application of training stimulus on a regular basis with some consideration to intensity, volume and frequency is the best formula for improved performance. Sebastian Kienle was interviewed by Bob Babbitt on his show last week. Great interview - Seb is hilarious and very thoughtful in his response. Bob kept asking him about his "turning point" as a professional athlete (he was after the "story" from a media perspective). Seb corrected Bob on multiple occasions, being a two time World 70.3 Champion and one time World Ironman Champion topping the heaps of other results and accolades he has accumulated over more than 15 years, that there was no turning point....rather there was a turning evolution...all his performances happened in due course and deservedly so. He credits his consistency to training (years and years of it) for his outstanding performances. Seb's website is: 

Consider your training methodology and how frequently you practice the skill of movement, train your aerobic system and develop movement efficiency. Consistency rules. Its the volume and intensity that become the moving targets.