Effects of acute exercise intensity on anabolic and catabolic mediators in trained and untrained children

الملخص EN

Background : This study was undertaken to study the effect of acute exercise bouts with different intensities on anabolic (insulin like growth factor-1, IGF-1) and catabolic (soluble tumor necrosis factor receptor-2, sTNFR2) mediators in trained and untrained children.

Subjects and Methods : Fifteen (7 females and 8 males) untrained children and fifteen (5 female and 10 males) trained children were included in the study.

All subjects performed 3 different exercise sessions including low (at 50 % HR max), moderate (at 70 % HR max) and high (at 90 % HR max) intensity exercise with measurement of IGF-1 and sTNFR2 by ELISA before and after each exercise setting.

Results : Trained children exhibited basal significant lower serum IGF-1 (P < 0.05) and higher serum sTNFR2 (P < 0.01) compared to untrained subjects.

Acute bouts of exercise significantly increased serum IGF-1 with low (P < 0.01), moderate (P < 0.001) and high (P < 0.001) intensity exercise sessions and concomitantly decreased serum sTNFR2 after all levels of acute exercise (P < 0.001) in untrained subjects.

Also, trained subjects developed significant increase in IGF-1 (P < 0.001) and decrease in sTNFR2 (P < 0.001) in response to all three acute exercise settings.

The higher response of both mediators to exercise was found with moderate intensity exercise compared to low intensity (P < 0.01 and P 0.01) and high intensity exercise (P < 0.01 and P < 0.01) in trained and untrained subjects.

However, the degree of response of IGF-1 and sTNFR2 to exercise bouts were significantly higher in trained group than untrained groups as regard to low (P < 0.001 and P < 0.001) and moderate (P < 0.001 and P < 0.001) and high intensity (P < 0.001 and P < 0.05).

Conclusion : Although trained children demonstrated hormonal adaptation consistent with catabolic state, all levels of acute exercise induced anabolic effect as manifested by increased IGF-1 and decreased sTNFR2 in trained and untrained children.

So, based on this metabolic evidence, promotion of repeated exercise bouts, especially of moderate intensity, should be encouraged in health care and in competitive sports.