Effects of polarized training vs. other training intensity distribution models on physiological variables and endurance performance in different-level endurance athletes: a scoping review - Rivera-Köfler, T.; Varela-Sanz, A.; Padrón-Cabo, A.; Giráldez-García, M. A.; Muñoz-Pérez, I. (The Journal of Strength and Conditioning Research, 2025)