Scaling isometric mid-thigh pull maximum strength in division I Athletes: are we meeting the assumptions?

This study examined the validity of various scaling methods, isometric mid-thigh pull (IMTP) peak force using various scaling methods, and the relationships between IMTP peak force and countermovement jump height.  Fifty-one collegiate baseball and soccer athletes performed two maximal IMTPs.  Absolute peak force was compared between teams and when data were scaled using ratio (RS), traditional allometric (ALLO), and fitted allometric (ALLO) scaling.  ALLO and ALLO validity was violated because different derived exponents existed for baseball ( = 0.20) and soccer ( = 1.20).  Soccer athletes produced greater RS peak force compared to baseball ( = 0.012), while no difference existed with absolute, ALLO or ALLO (all > 0.05) peak force.  Moderate relationships existed between body mass and absolute ( = 0.402, = 0.003) and RS ( = -0.328, = 0.019) peak force, while trivial relationships existed with ALLO and ALLO (both < -0.10, > 0.05).  Trivial relationships existed between countermovement jump height and absolute, RS, ALLO, and ALLO (all < 0.20, > 0.05) peak force.  The current dataset violated allometric scaling assumptions, making it inappropriate to use ALLO and ALLO scaling.  Practitioners must understand the assumptions, limitations, and purpose of scaling methods.