Blood pressure during leg extension in children

This study investigated blood pressure responses (BP) during bilateral leg extension in healthy children at different numbers of repetitions. BP was measured non-invasively during 1 repetition maximum (1RM), 5 repetitions at 85-90% of 1RM (5 R), 30 repetitions at 35-40% of 1RM (30 R) and during 5 s of maximal isometric work (5SM). It is important to investigate if maximal strength testing in healthy children provokes an unfavourable rise in BP, in order to be able to do further research on hypertensive risk groups of children. 39 (18 male and 21 female) healthy children (10.5 ± 2.0 years old) participated in this study. Peak BP values and peak HR increased significantly with increasing number of repetitions. Peak BP increased from 1RM (144 ± 16/110 ± 19 mmHg) to 30R (170 ± 26/123 ± 21 mmHg) and peak HR increased from 1RM (122 ± 10 bpm) to 30 R (147 ± 14 bpm). 30R also gave significantly higher BP and HR than 5SM (156 ± 24/120 ± 23 mmHg and 131 ± 16 bpm, respectively). The boys had significantly higher diastolic BP during 1RM than the girls and significantly higher BP during 5SM. In conclusion, maximal strength testing induced lower increases in BP than submaximal strength testing with more repetitions, and may be performed in healthy children within safe BP limits (< 225 mmHg in systolic BP).