Dowling Brittany, McElheny Kathryn D, Camp Christopher L, Ling Daphne I, Dines Joshua S
Research and Development, Motus Global, Rockville Centre, New York, USA.
Sports Medicine and Shoulder Service, Hospital for Special Surgery, New York, New York, USA.
Orthop J Sports Med. 2020 Dec 10;8(12):2325967120969245. doi: 10.1177/2325967120969245. eCollection 2020 Dec.
Although the monitoring of a pitcher's throwing arm workload has become a hot topic in both research and the pitching world, the impact of mound height and distance still remains unclear.
To compare the kinetics and kinematics between pitches from a mound and flat ground at 2 different distances.
Descriptive laboratory study.
A total of 21 healthy high school varsity baseball pitchers (age, 16.2 ± 1.3 years; weight, 73.6 ± 11.0 kg; height, 181.3 ± 6.4 cm) participated in this study. Players were fitted with a motusBASEBALL sensor and sleeve. Each pitcher was instructed to pitch 5 fastballs under 4 conditions: mound at 60.5 ft (regulation distance), flat ground at 60.5 ft, mound at 50.5 ft, and flat ground at 50.5 ft. Linear mixed-effects models were used to account for both intra- and interplayer variability. A multivariable model was used to evaluate the association of mound pitching, flat-ground pitching, and their distances (50.5 ft and 60.5 ft), and their interaction to arm speed, arm slot, arm rotation, elbow varus torque, and ball velocity.
There were no statistically significant effects of mound, flat-ground, or distance variation on arm speed or shoulder rotation. Arm slot was significantly higher (+3.0°; = .02) on pitches from the mound at 60.5 ft compared with 50.5 ft. Elbow varus torque was lower (-1.5 N·m; = .02) on mound pitches at 60.5 ft compared with 50.5 ft. Pitches thrown from the mound displayed significantly faster ball velocity compared with flat-ground pitches at both distances ( < .01 for both), with pitches at 60.5 ft having higher velocity (+0.7 m/s; < .01).
Contrary to long-standing notions, the study results suggest that pitching from the mound does not significantly increase stress on the elbow compared with flat-ground pitching. Lower elbow varus torque and faster ball velocity at the regulation distance compared with the reduced distance indicate that elbow stress and ball velocity may not correlate perfectly, and radar guns may not be an appropriate surrogate measure of elbow varus torque.
A better understanding of the kinetic and kinematic implications of various throwing programs will allow for the designing of programs that are driven by objective data with aims directed toward injury prevention and rehabilitation in baseball pitchers.
尽管投手投球手臂工作量的监测已成为研究和投球领域的热门话题，但投手丘高度和距离的影响仍不明确。
比较在两个不同距离下从投手丘和平地投球之间的动力学和运动学差异。
描述性实验室研究。
共有21名健康的高中校队棒球投手（年龄16.2±1.3岁；体重73.6±11.0千克；身高181.3±6.4厘米）参与本研究。球员佩戴motusBASEBALL传感器和护臂。每位投手被要求在4种条件下投5次快速球：60.5英尺（标准距离）的投手丘、60.5英尺的平地、50.5英尺的投手丘和50.5英尺的平地。使用线性混合效应模型来考虑球员内部和球员之间的变异性。使用多变量模型评估投手丘投球、平地投球及其距离（50.5英尺和60.5英尺）以及它们与手臂速度、手臂角度、手臂旋转、肘内翻扭矩和球速之间的关联及相互作用。
投手丘、平地或距离变化对手臂速度或肩部旋转没有统计学上的显著影响。与50.5英尺的投手丘相比，在60.5英尺投手丘投球时手臂角度显著更高（增加3.0°；P = 0.02）。与50.5英尺的投手丘相比，在60.5英尺投手丘投球时肘内翻扭矩更低（减少1.5牛·米；P = 0.02）。在两个距离下，从投手丘投出的球速均显著快于平地投球（两者P均<0.01），60.5英尺投球时速度更高（快0.7米/秒；P <0.01）。
与长期以来的观念相反，研究结果表明，与平地投球相比，从投手丘投球并不会显著增加肘部压力。与缩短距离相比，标准距离下肘内翻扭矩更低且球速更快，这表明肘部压力和球速可能并非完美相关，测速枪可能不是肘内翻扭矩的合适替代测量指标。
更好地理解各种投球方案的动力学和运动学影响，将有助于设计以客观数据为驱动、旨在预防和康复棒球投手损伤的方案。
