Background:

Throwing arm injuries are common because of the demand on the shoulder. The shoulder is qualitatively checked regularly by team physicians. Excessive instability and joint loading in baseball pitching are risk factors for throwing arm injuries. Knowledge of shoulder flexibility, range of motion, and joint loading may provide new insights for treatments to reduce the likelihood of injury incidence.

Purpose:

To investigate the relationship among injuries, shoulder external rotational properties, and shoulder joint loading in baseball pitchers.

Study Design:

Descriptive laboratory study.

Methods:

Pitching kinetics, shoulder rotational tests, and self-reported injury questionnaires were used to study 177 collegiate baseball pitchers. Pitching motion data were collected at 240 Hz using a motion capture system. A custom program calculated the shoulder joint loading. The shoulder rotational test quantitatively records shoulder range of motion and flexibility using a custom-made wireless device. Self-reported injury questionnaires were filled out during tests and yearly follow-ups. The total length of the study was 5 years. Analysis of variance, chi-square, and regression tests were performed to compare differences among groups and detect correlations with surgery and shoulder joint loadings.

Results:

There were significant differences in shoulder flexibility among surgery groups. Shoulder external rotational properties during physical examination were significantly associated with shoulder joint loading in baseball pitching. High shoulder external rotation was associated with 14% to 36% lower shoulder posterior force and adduction, internal rotation, and horizontal adduction torque (P < .05). High shoulder flexibility was associated with 13% higher anterior force (P < .05). High shoulder external rotation before external rotation torque was applied was associated with 13% to 33% lower shoulder inferior force and adduction, internal rotation, and horizontal adduction torque (P < .05). There were no significant differences in shoulder joint loading among the surgery groups.

Conclusion:

Shoulder injuries that require surgery were associated with shoulder external rotation flexibility. High shoulder external rotation may be advantageous because it lowers the force and torque on the shoulder joint.

Clinical Relevance:

The ability to understand shoulder external rotational properties, joint loading, and injury during baseball pitching helps further our understanding of injury mechanisms. The shoulder rotational test should be used as a screening tool to identify players at risk.

中文翻译：

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体格检查期间肩部外旋特性与棒球投球期间需要手术和肩关节负荷的损伤有关

背景：

由于对肩部的需求，投掷手臂受伤很常见。肩部由团队医生定期进行定性检查。棒球投球中过度的不稳定性和关节负荷是投掷手臂受伤的危险因素。了解肩部柔韧性、运动范围和关节负荷可能为治疗提供新的见解，以减少受伤发生的可能性。

目的：

调查棒球投手受伤、肩部外旋特性和肩关节负荷之间的关系。

学习规划：

描述性实验室研究。

方法：

投球动力学、肩部旋转测试和自我报告的伤害问卷被用来研究 177 名大学棒球投手。使用运动捕捉系统以 240 Hz 的频率收集俯仰运动数据。自定义程序计算肩关节负荷。肩部旋转测试使用定制的无线设备定量记录肩部的运动范围和灵活性。在测试和年度随访期间填写自我报告的伤害问卷。研究总时长为5年。进行方差分析、卡方检验和回归检验以比较组间差异并检测与手术和肩关节负荷的相关性。

结果：

手术组之间的肩部灵活性存在显着差异。体格检查期间的肩部外旋特性与棒球投球中的肩关节负荷显着相关。高肩外旋与 14% 至 36% 的肩后力和内收、内旋和水平内收扭矩降低有关 ( P < .05)。较高的肩部柔韧性与 13% 的更高的前向力相关 ( P < .05)。施加外旋扭矩前的高肩外旋与 13% 至 33% 的较低肩关节下力和内收、内旋和水平内收扭矩相关（P< .05）。手术组之间的肩关节负荷没有显着差异。

结论：

需要手术的肩部损伤与肩部外旋灵活性有关。高肩外旋可能是有利的，因为它降低了肩关节上的力和扭矩。

临床相关性：

了解棒球投球过程中肩部外旋特性、关节负荷和损伤的能力有助于我们进一步了解损伤机制。肩部旋转测试应用作筛选工具，以识别有风险的球员。