Training camps are widely applied by the national sports system as the key element of a precompetitive training and selection process, with the coaching teams assisted in the selections by the relevant theoretical provisions and study findings - although many would like to have reliable fitness marker(s) to effectively rate the precompetitive fitness and compose the picked teams for the sport aerobics events. We would recommend for the competitive success forecasting purposes a Difficult Elements Execution Rate computed in the four-week precompetitive fitness tests at the training camps. The Difficult Elements Execution Rate would be computed for a competitive routine as the successfully executed difficult elements to the total elements ratio - compliant to the valid difficulty scales applied in competitions by referees, i.e. an ideal execution is ratable by Difficult Elements Execution Rate =100%. Sampled for the study in 2008 through 2018 was the Russian national team. The champions were tested with the highest Difficult Elements Execution Rate rates and Difficult Elements Execution Rate growths over the 4-weekly trainings; whilst the runner-ups were tested with some Difficult Elements Execution Rate sags on training weeks 2-3. We believe that the Difficult Elements Execution Rate rates may be successfully applied for the competitive success forecasting and precompetitive training system correction purposes.