I believe strongly a lot of poor results are the result of training in isolation. Training one component at the expense of others. Let’s take work capacity/endurance/stamina as an example, I wrote before that coaches shouldn’t look at work capacity in the sense of how much work they get done, but in terms of power endurance, but even then that training should be geared to event specificity. Playing with volume, densities, and load to extract a number of high quality, high intensity efforts in practice or competition. Fixing differences between any two given athletes takes time, patience, persistence, and adherence to good training models with different training plans.