The purpose of the study was three-fold: (i) to describe ball speed and arm speed during power jump serve in volleyball; (ii) compare the outcomes among playing positions, and (iii) analyze the relationships among outcomes. One middle blocker (MI), three opposites (OP), three setters (S), and six outside hitters or receiver-attackers (RA) youth elite volleyball players from the French national team participated in this study. This cross-sectional study analyzed the ball and arm speeds while serving over two consecutive weeks. A total of 150 valid power speed serves (ball speed = 103.0 ± 7.0 km h⁻¹; arm speed = 40.0 ± 4.2 km h⁻¹) were recorded during the six training sessions using a radar-gun and an inertial measurement unit. Ball speed varied from 90 to 110 km h⁻¹, while the coefficient of variation ranged from 1.5% to 7.5%. Arm speed varied between 35 and 45 km h⁻¹, while the coefficient of variation ranged between 2 and 14%. One-way ANOVA revealed significant differences among playing positions for the variables of ball speed (p = 0.018), arm speed (p = 0.019) and ratio of ball to arm speed (p = 0.002). Very large correlations between arm speed and the ratio of ball speed to arm speed were found (r = −0.77 [−0.83; −0.69]; p ≤ 0.001). The results suggest that players reduce their variability regarding the outcome. Finally, despite being related, the velocity of the arm and ball were not perfectly correlated. Thus, measuring both the arm and ball velocity may be necessary.

研究的目的是三方面的：（i）描述排球力量跳跃发球时的球速和臂速；（ii）比较比赛位置之间的结果，以及（iii）分析结果之间的关系。来自法国国家队的一名中级盖帽手（MI），三个对垒（OP），三个二传手（S）和六名外部击手或接球手（RA）青年精英排球运动员参加了这项研究。这项横断面研究分析了连续两个星期内的球和手臂速度。在六次训练期间，使用雷达炮和惯性测量单元记录了总共150次有效功率速度服务（球速= 103.0±7.0 km h ^-1；手臂速度= 40.0±4.2 km h ^-1）。球速从90到110 km h ^-1不等，而变异系数则介于1.5％至7.5％之间。手臂速度在35至45 km h ^-1之间变化，而变异系数在2至14％之间。单向方差分析显示，在不同球速（p  = 0.018），臂速（p  = 0.019）和球臂速比（p  = 0.002）的比赛位置之间存在显着差异。发现臂速与球速与臂速之比之间的相关性非常大（r  = -0.77 [-0.83; -0.69]; p ≤0.001）。结果表明，参与者减少了关于结果的可变性。最后，尽管存在相关性，但手臂和球的速度并没有完全相关。因此，可能需要同时测量臂速和球速。