Tripp Brady L, Yochem Eric M, Uhl Timothy L
Department of Athletic Training, College of Nursing and Health Sciences, Florida International University, University Park, ZEB 250B, 11200 SW 8th Street, Miami, FL 33199, USA.
J Athl Train. 2007 Oct-Dec;42(4):452-7.
Research indicates that upper extremity fatigue hampers sensorimotor system acuity. However, no investigators have observed recovery of upper extremity acuity after fatigue.
To observe recovery of active position reproduction acuity in overhead throwers after a throwing-fatigue protocol.
Single-session, repeated-measures design.
University musculoskeletal laboratory.
Sixteen healthy collegiate baseball players (age = 21.0 +/- 1.6 years, height = 175.8 +/- 10.2 cm, mass = 82.8 +/- 4.3 kg).
INTERVENTION(S): Subjects threw a baseball with maximum velocity (every 5 seconds) from a single knee. Every 20 throws, subjects rated their upper extremity exertion on a Borg scale until reporting a level of more than 14.
MAIN OUTCOME MEASURE(S): We used an electromagnetic tracking system to measure active multijoint position reproduction acuity at 5 intervals: prefatigue; immediately postfatigue; and after 4, 7, and 10 minutes of recovery. Blindfolded subjects reproduced their arm-cocked and ball-release positions. Dependent variables were 3-dimensional variable errors of scapulothoracic, glenohumeral, elbow, and wrist joints; endpoint (ie, hand) position error represented overall upper extremity acuity. The independent variable was time (measured prefatigue and at 4 postfatigue intervals).
Fatigue significantly affected acuity of scapulothoracic, glenohumeral, and elbow joints and endpoint error for both positions (P < .001). Fatigue significantly affected wrist acuity only for ball release (P < .001). For arm-cocked reproduction, each measure of acuity, except that of the glenohumeral joint, recovered by 7 minutes; for ball release, each measure of acuity recovered within 4 minutes (P > .05).
The sensorimotor system deficits that we observed after fatigue recovered within 7 minutes in most upper extremity joints. Glenohumeral arm-cocked position reproduction acuity failed to recover within 10 minutes. Research indicates that overhead throwers are vulnerable in this position to the capsulolabral injuries commonly observed in throwing athletes. Future researchers should explore this relationship and the effectiveness of exercises aimed at enhancing sensorimotor system acuity and endurance.
研究表明上肢疲劳会妨碍感觉运动系统的敏锐度。然而，尚无研究人员观察到疲劳后上肢敏锐度的恢复情况。
观察经过投掷疲劳方案后，过头投掷运动员主动位置再现敏锐度的恢复情况。
单节次重复测量设计。
大学肌肉骨骼实验室。
16名健康的大学棒球运动员（年龄 = 21.0 ± 1.6岁，身高 = 175.8 ± 10.2厘米，体重 = 82.8 ± 4.3千克）。
受试者单膝跪地以最大速度（每5秒）投掷棒球。每投掷20次，受试者使用Borg量表对其上肢用力程度进行评分，直至报告超过14级。
我们使用电磁跟踪系统在5个时间点测量主动多关节位置再现敏锐度：疲劳前；疲劳后即刻；以及恢复4、7和10分钟后。蒙眼受试者再现其手臂上举和球出手时的位置。因变量为肩胛胸壁、盂肱、肘部和腕关节的三维可变误差；终点（即手部）位置误差代表整体上肢敏锐度。自变量为时间（在疲劳前和疲劳后4个时间点测量）。
疲劳显著影响肩胛胸壁、盂肱和肘关节的敏锐度以及两个位置的终点误差（P < .001）。疲劳仅在球出手时显著影响腕关节敏锐度（P < .001）。对于手臂上举的再现，除盂肱关节外，每项敏锐度指标在7分钟内恢复；对于球出手，每项敏锐度指标在4分钟内恢复（P > .05）。
我们观察到的疲劳后感觉运动系统缺陷在大多数上肢关节中7分钟内恢复。盂肱关节手臂上举位置再现敏锐度在10分钟内未恢复。研究表明，过头投掷运动员在这个位置易患投掷运动员中常见的关节唇损伤。未来的研究人员应探索这种关系以及旨在提高感觉运动系统敏锐度和耐力的运动的有效性。
