A 12-week aerobic training programme reduced plasmatic allantoin in adolescents with Down syndrome.

OBJECTIVE: To assess the influence of a 12-week training programme on plasmatic levels of allantoin, an in vivo marker for oxidative stress, in adolescents with Down syndrome. This finding would be of great interest, since oxidative damage has been proposed as a pathogenic mechanism of several pathologies in this population. MATERIALS: To reach this goal, 31 male adolescents with Down syndrome (16.3 (1.1) years; 155.2 (5.7) cm; 70.8 (4.5) kg) performed a 12-week training programme, three sessions per week, consisting of warm-up (15 min) followed by a main part (20-35 min (increasing 5 min each 3 weeks)) at a work intensity of 60-75% of peak heart rate (increasing by 5% each 3 weeks) and then a cool-down period (10 min). According to previous studies, it should be emphasised that the maximal heart rate for individuals with Down syndrome was predicted by the equation HRmax = 194.5-(0.56 age). The control group included seven age-, sex- and BMI-matched adolescents with trisomy 21 that did not perform any training programme. The levels uric acid and allantoin were assayed in plasma by HPLC. This protocol was approved by an institutional ethics committee. RESULTS: When compared with baseline, plasmatic levels of allantoin were decreased significantly (22.09 (1.62) vs 18.74 (1.38) micromol/l; p<0.001) after being exercised. Furthermore, the allantoin/uric acid ratio was decreased significantly (0.071 (0.006) vs 0.059 (0.004); p<0.05). On the contrary, no changes were reported in controls. CONCLUSION: A 12-week aerobic programme significantly reduced oxidative damage expressed in terms of plasmatic allantoin content in adolescents with Down syndrome. Further studies on this topic are required.

Valoraçäo da influência dos ritmos circadianos nop rendimento desportivo de velocistas / Valuation of the influence of the circadian rhythms in the athletic

Neste trabalho estuda-se a influência que os ritmos circadianos exercem no rendimento desportivo de velocistas em provas de 50 metros rasos. Para isso, 13 velocistas seguiräo um estrito protocolo que fixa os horários de sono/vigília, refeiçöes e controle de variáveis (rendimento em velocidade, teste de Bosco, testes de auto-estima psíquica e física e temperatura corporal) durante 3 dias näo consecutivos. No primeiro dia, segui-se o horário base, enquanto que no segundo (dia de antecipaçäo) e terceiro (dia de atraso) se adiantou e atrasou o mesmo horário em 2 horas, respectivamente. Da análise dos resultados deduz-se que o momento máximo de rendimento em velocidade se produz à tarde (19 horas). Existe uma maior dificuldade ao modificar os picos de máximo rendimento no sentido de antecipar, registrando um deterioro estatisticamente significativo do rendimento médio do dia de antecipaçäo em relaçäo ao dia de controle. Por último, o teste de Bosco, o teste de auto valoraçäo psíquica e física apresentaram uma relaçäo muito direta com o rendimento em velocidade pelo que podem ser empregues em autorritometria.