Effects of Oral Leak Size on Valsalva Responses.

Introduction: We hypothesized that oral leak size, a hitherto unstudied technical variable, would influence hemodynamic responses and difficulty level in executing the Valsalva maneuver (VM). Methods: Based on power analysis, 38 healthy participants were included. Oral leak size in random order was 0.35, 0.71, 1.01,1.40 mm. Level of difficulty was rated 1 to 10, with ≥7-10 being severe. VM was performed at 40 mmHg expiratory strain for 15 s. Three trials were averaged for each leak size. Data were analyzed by repeated measures ANOVA and pairwise comparisons with Tukey adjustment, a mixed effect model, and a generalized linear model. Results: Of the 38 participants, 4 were excluded from analysis for protocol deviation. Phase II L mean BP (MBP) was significantly higher with the largest leak versus all others (P < 0.001). TL was significantly lower with the largest leak versus all others (P = 0.0029). Difficulty performing the VM increased significantly with every increase in leak size (P < 0.001), and a significantly higher percentage of participants reported severe difficulty with leak 4 compared with leak 1 (P < 0.001), 2 (P = 0.0068), and 3 (P = 0.0068). There was no significant effect of phase II E SBP decline on phase II L MBP increase (P = 0.0752). Difficulty increased significantly with one unit increase in phase II L MBP (P = 0.0002). Conclusions: Oral leak size affected VM hemodynamic parameters and level of difficulty. Oral leak size exceeding 1.01 mm significantly affected phase II L MBP. Level of difficulty rose with increasing leak size and was significantly correlated with increase in phase II L MBP.

Comparison of technical and physical activities between 8 vs. 8 and 11 vs. 11 games in young Korean soccer players.

The aims of this study were to examine the differences in technical aspects and physical demands between small-size games (SSG; 8 vs. 8) and regular-size games (RSG; 11 vs. 11) in young Korean soccer players. Seventy-nine young soccer players from 6 teams (U-12) volunteered to participate in the study. The players completed 4 games (2 SSG, 62×51 m, and 2 RSG, 80×54 m) in 2 days. Each game was filmed to evaluate technical actions. Physical demand variables were measured using global positioning system technology. SSG showed significantly greater numbers of technical plays among 17 variables when compared to RSG (P<0.05). The players covered significantly greater total distance during low-, moderate-, and high-speed running and sprinting in SSG than in RSG (P<0.05). Higher numbers of high-intensity activities (repeated high-intensity efforts, explosive efforts, decelera-tions, accelerations, and sprinting) were observed in SSG compared to RSG (P<0.05). Mean heart rate was also higher in SSG than in RSG (P<0.05). Despite the greater physical demands during SSG, the exercise intensity was similar to that reported in previous studies. Therefore, the SSG format applied in the present study can be a suitable official game format for Korean young soccer players, resulting in significantly greater exposure to technical plays without excessive physical demands.