EFFECT OF ALTITUDE AND SOCIOECONOMIC-STATUS ON VO2MAX AND ANAEROBIC POWER IN PREPUBERTAL BOLIVIAN GIRLS

The aim of this work was to evaluate the effects of high altitude and low socioeconomic status (SES) on aerobic and anaerobic power in 11-yr -old Bolivian girls. At both high (3,600 m) and low (420 m) altitudes, low-SES groups of girls were compared to similarly aged, high-SES gir ls. At low altitude, low-SES girls were also compared with younger hig h-SES girls with the same anthropometric characteristics. Anthropometr ic data were similar between high-SES and low-SES girls at both altitu des, but low-SES girls showed a 9-mo growth delay. Maximal O-2 uptake was significantly lower for low-SES girls at both altitudes. Values di d not differ when expressed relative to body weight at high altitude f or high-SES vs. low-SES girls (37.6 +/- 1.2 vs. 39.3 +/- 1.0 ml . min( -1) . kg body wt(-1)), but a difference persisted at low altitude betw een high- and low-SES girls (37.5 +/- 1.0 vs. 34.7 +/- 0.7 ml . min(-1 ) kg body wt(-1)). Anaerobic power (P-max, force-velocity test; P-Wing , Wingate test) was reduced for low-SES girls at both altitudes, whate ver the mode of expression. For a given SES, the relative anaerobic pe rformances were lower at low altitude. At low altitude, low-SES girls developed lower anaerobic power than did younger high-SES girls with s imilar anthropometric characteristics. In conclusion, at both altitude s, the reduction of anaerobic performances observed in girls of low SE S could not be totally explained by anthropometric factors. Structural and/or functional muscle alterations are suggested. Moreover, at low altitude, tropical and other factors may have contributed to differenc es in performance between low- and high-SES girls.