Differences in motor performance between children and adolescents in Mozambique and Portugal: impact of allometric scaling

Background: Children from developed and developing countries have different anthropometric characteristics which may affect their motor performance (MP). Aim: To use the allometric approach to model the relationship between body size and MP in youth from two countries differing in socio-economic status—Portugal and Mozambique. Subjects and methods: A total of 2946 subjects, 1280 Mozambicans (688 girls) and 1666 Portuguese (826 girls), aged 10–15 years were sampled. Height and weight were measured and the reciprocal ponderal index (RPI) was computed. MP included handgrip strength, 1-mile run/walk, curl-ups and standing long jump tests. A multiplicative allometric model was adopted to adjust for body size differences across countries. Results: Differences in MP between Mozambican and Portuguese children exist, invariably favouring the latter. The allometric models used to adjust MP for differences in body size identified the optimal body shape to be either the RPI or even more linear, i.e. approximately (height/mass0.25). Having adjusted the MP variables for differences in body size, the differences between Mozambican and Portuguese children were invariably reduced and, in the case of grip strength, reversed. Conclusion: These results reinforce the notion that significant differences exist in MP across countries, even after adjusting for differences in body size.