220 Pediatric Exercise Science, 2009, 21, 220-232 © 2009 Human Kinetics, Inc. Allometric Associations Between Body Size, Shape, and Physical Performance of Greek Children Alan Nevill, Georgia Tsiotra, Panagiotis Tsimeas, and Yiannis Koutedakis We adopted allometric models to identify the most appropriate body size/shape char- acteristics associated with physical performance activities of Greek school children. Children underwent assessments for aerobic and anaerobic itness, lexibility and hand-grip strength. Results suggest that the inverse Ponderal index and not BMI is the most appropriate body-shape indicator associated with running and jumping activi- ties. Height was negatively associated with lexibility, but both height and weight were positively associated with hand-grip strength. In conclusion, allometric models provide a valuable insight into the most appropriate body size and shape characteris- tics associated with children’s physical performances and at the same time ensure valid inference when investigating group/population differences (e.g., between gender and maturation status). Human physique consists of the three distinct but interrelated anthropometric components of body size, structure and composition (17). Body size refers to the physical magnitude of the body and its segments (stature, mass, surface area, etc). Body structure or shape describes the distribution of body parts expressed as ratios, such as the body mass index (BMI), the inverse ponderal index or the head length-to-body length (exclusive of head) ratio. The later concept of shape was discussed by Mosimann (10), who deined the term shape as the ratio of two body dimensions measured in the same units that would yield a “dimensionless” ratio variable relecting body shape. The curial index (simplistically deined as the leg height below the knee divided by the leg height above the knee) is a typical exam- ple. Body composition consists of the amount of various constituents in the body such as fat, muscle, bone, etc. Slaughter and Christ (17) explained why the assessment of these body phy- sique components is important when investigating aspects of physical performance. Nevill is with University of Wolverhampton Research Institute of Healthcare Sciences, Wolverhampton, WS1 3BD, UK; Tsiotra is with University of Wolverhampton Research Institute of Healthcare Sciences and Institute of Human Performance & Rehabilitation, CERETETH, 42100 Trikala, Greece; Tsimeas is with Sport & Exercise Sciences, University of Thessaly, 42100 Trikala, Greece; Koutedakis is with University of Wolverhampton Research Institute of Healthcare Sciences, the Institute of Human Performance & Rehabilitation, CERETETH, and Sport & Exercise Sciences, University of Thessaly, 42100 Trikala, Greece.