优秀击剑运动员下肢三关节等速肌力测试分析

目的:研究我国优秀击剑运动员下肢髋、膝、踝三关节肌群等速肌力表现,找出薄弱肌群。方法:国家击剑队备战2008年奥运会重点队员26名,男女各13名,年龄23.1±2.36岁。在60°/s、240°/s速度下测定运动员双侧下肢髋、膝、踝屈伸肌群等速向心峰力矩。结果发现:(1)髋关节:在240°/s下双侧伸肌峰力矩均明显低于60°/s(P<0.05),60°/s和240°/s下双侧髋关节屈肌峰力矩无显著差异(P>0.05);男运动员两个速度下前腿伸肌峰力矩均显著高于后腿(P<0.05),女运动员无显著差异(P>0.05);两个速度下,运动员双腿屈伸肌峰力矩比值低于正常。(2)膝关节:60°/s时男运动员双腿屈伸肌峰力矩有显著差异(P<0.05),240°/s时双侧伸肌峰力矩有显著差异(P<0.05),女运动员两个速度下均无显著差异(P>0.05);60°/s时,女运动员前后腿屈伸肌峰力矩比值分别为0.56和0.54,男运动员分别为0.63和0.67;240/°s时男女前后腿屈伸肌峰力矩比值均在正常范围。(3)踝关节:60°/s时男运动员前腿踝关节屈伸肌峰力矩显著大于后腿(P<0.05),240°/s时无显著差异(P>0.05);两个速度下,女运动员踝关节屈伸肌峰力矩均无显著性差异(P>0.05);运动员踝关节屈伸峰力矩比值在两个速度下均低于正常。结论:优秀男子击剑运动员下肢关节等速肌力双侧不对称,女运动员不对称表现不明显;击剑运动员下肢薄弱肌群为后腿髋关节伸肌群、股后肌群、前腿股后肌群及踝关节背伸肌群。     

机械性踝关节不稳患者踝屈、伸肌群等速肌力评价

目的:评价机械性踝关节不稳(mechanical ankle instability,MAI)患者踝屈、伸肌群的等速肌力。方法:20名单侧机械性踝关节不稳患者的双侧踝关节分别接受等速肌力测试(60°/s和120°/s)。比较患侧和健侧踝关节屈、伸肌群相对峰力矩、平均功率、总功和屈伸力矩比的差异。结果:60°/s时,两侧伸肌群相对峰力矩、平均功率及总功的差别均无统计学意义(P=0.303,P=0.548,P=0.452),屈肌群相对峰力矩、平均功率和屈伸力矩比均无显著性差异(P=0.417,P=0.275,P=0.870),但屈肌群总功有显著性差异(P=0.043)。120°/s时,两侧伸肌群相对峰力矩、平均功率及总功差别均无统计学意义(P=0.096,P=0.069,P=0.233),但屈肌群相对峰力矩、平均功率、总功和屈伸力矩比有显著性差异(P=0.030,P=0.043,P=0.017,P=0.036)。结论:机械性踝关节不稳患者患侧踝关节跖屈肌群快速运动时肌力下降,这可能与其踝关节稳定性有关。     

运动性肩袖损伤表面肌电及等速肌力测试研究

目的:探讨分析运动性肩袖损伤后肩袖肌群表面肌电和等速肌力测试特征的变化。方法:选取肩袖损伤的运动员30例,其中男18例,女12例,平均年龄为21.2±2.2岁。同时选取同一院系年龄、性别构成比相近的健康运动员30例作为对照组,其中男16例,女14例,平均年龄为21.5±2.0岁。两组患者均同时进行表面肌电和等速肌力测试。结果:肩袖损伤组运动员肩关节在角速度为60°/s,90°/s外展时冈上肌、冈下肌积分肌电值(i EMG)值比对照组低,差异有统计学意义(P<0.05),尤其是冈下肌差异更显著(P<0.01)。肩袖损伤组运动员肩关节在角速度为120°/s外展时冈上肌、冈下肌i EMG值比对照组低,差异有统计学意义(P<0.01)。肩袖损伤组运动员肩关节在角速度为60°/s外旋时所有肌肉i EMG值与对照组比较,差异无统计学意义(P>0.05);肩袖损伤组运动员肩关节在角速度为90°/s、120°/s外旋时冈下肌i EMG值比对照组低,差异有统计学意义(P<0.05)。与对照组比较,肩袖损伤组运动员肩关节在角速度为60°/s,90°/s,120°/s外旋时所有肌肉i EMG值均无明显改变(P>0.05)。肩袖损伤组运动员肩关节在角速度为60°/s,90°/s,120°/s时的外旋/内旋,外展/内收峰力矩值比对照组低,差异有统计学意义(P<0.05或P<0.01)。结论:肩袖损伤运动员在外展时冈上肌、冈下肌肌肉募集较差,而三角肌、小圆肌无异常;同时,肩袖损伤后三角肌中束和冈上肌合力作用下降而致肩关节外展能力减弱。     

上肢过顶投掷类运动中继发性喙突下撞击症的机制探讨——功能解剖和生物力学研究

目的:探讨上肢过顶运动中发生继发性喙突下撞击症的机制和特点,为临床诊疗提供依据。方法:16具成人尸体32例肩关节标本上,在肩胛下肌离断前后,观察上肢过顶运动中肩袖间隙与喙突之间的动态关系;自制生物力学测定仪检测肩外展90°位外旋活动度的变化;以压敏片检测肩外展90°位最大程度外旋时肩袖间隙与喙突间接触面积和压力的改变。结果:(1)肩外展位外旋时,肱骨头有向前方移位的趋势,肩胛下肌离断后肱骨头前移更加明显;(2)肩外展90°位的最大外旋活动度,在肩胛下肌离断后明显增大;(3)肩外展90°位最大程度外旋时肩袖间隙与喙突接触面积和压力,在肩胛下肌离断后明显增大。结论:(1)肩胛下肌损伤后导致肩关节前方不稳定,肩外展外旋时肱骨头前移;(2)肩胛下肌损伤可能导致肩外展外旋时肱骨头与喙突的继发性撞击。     

中国女子篮球运动员膝关节等速肌力测试分析

目的:了解中国国家女子篮球队运动员膝关节等速肌力特征。方法:选用IsoMed 2000等速测试系统,采用60°/s、180°/s、240°/s三种角速度,测试18名中国女篮国家队运动员膝关节等速肌力。根据场上位置将运动员分为三组:后卫组7人(1、2号位),前锋组6人(3、4号位),中锋组5人(5号位),比较分析三组运动员的测试结果。结果:(1)女篮运动员双侧膝关节慢速测试时(60°/s)屈伸肌峰力矩(PT)显著高于快速测试(180°/s,240°/s),膝关节屈伸肌峰力矩比值(H/Q)随测试速度增加递增,左右膝H/Q无显著性差异。(2)慢速测试时(60°/s),左右膝关节峰力矩、峰力矩/体重比值、平均功率、H/Q无显著差异。(3)快速测试(240°/s)时,左膝屈肌PT、峰力矩/体重比值(PT/BW)显著高于右膝。180°/s测试时,左膝屈肌平均功率显著高于右膝。(4)60°/s测试时,后卫、前锋、中锋运动员PT、PT/BW组间比较无显著性差别。180°/s测试时,后卫运动员左膝屈肌PT与前锋、中锋运动员比较有显著性差异(P=0.02),各组间伸肌PT未见显著差异。240°/s测试时,后卫运动员右膝屈、伸肌PT/BW和中锋运动员比较均存在显著差异;后卫、前锋、中锋三组运动员平均功率、H/Q、总功与峰值功率组间比较均无显著性差别。结论:(1)女篮运动员快速测试(240°/s)时左膝屈肌力量强于右膝,反映快速运动时左右膝关节肌力不平衡。(2)不同场上位置女篮运动员膝关节等速肌力快速测试结果有差异性,提示力量训练应根据场上位置进行特异性训练。(3)女篮运动员需加强屈肌快速力量训练,以提高H/Q,预防膝关节损伤。     

健康男女青年前臂旋前、旋后肌群力量的研究

目的 :(1 )通过测试健康男女青年前臂旋肌群的力量 ,为运动训练、损伤和康复提供数据和科学依据 ;(2 )探讨健康青年前臂旋肌群的生物力学规律。方法 :利用CYBEX -60 0 0测力系统对健康男女青年前臂旋前、旋后肌群进行等长和等速测试。结果发现 ,在等长测试中 ,男女旋后肌群峰力矩随着测量角度的增加而减少、旋前肌群峰力矩随着测量角度增加而增加。在等速向心测试中 ,男女旋前、旋后肌群的峰力矩随着所测角速度的增加而减少。两种测试均表明旋前肌群峰力矩要大于旋后肌群的峰力矩 (P <0 0 5 )。男性与女性相比绝对力矩较大 (P <0 0 5 ) ,但去除体重因素后 ,男女力矩间的差距缩小。结果表明 ,用相对峰力矩比较男女间的差别更为合理。通过测试发现健康男女青年前臂旋的力量较薄弱 ,这可能与平时前臂旋肌锻炼少有关     

我国优秀女子铅球运动员投掷臂三关节等速肌力特征

目的:通过对我国优秀女子铅球运动员投掷臂关节等速肌力参数进行运动生物力学测试和分析,揭示不同训练水平女子铅球运动员的上肢力量特征,通过统计对比发现其力量素质中的差距和不足,为今后女子铅球项目的专项力量训练和同类研究提供理论参考。方法:采用ISO-MED2000等速测试系统测试获取4名我国最高水平女子铅球运动员投掷臂三关节60°/s和240°/s时向心等速运动屈、伸肌群峰力矩、相对峰力矩、屈伸肌峰力矩比、平均功率等参数,结合专项技术进行分析。结果:(1)国际健将组肩关节屈肌群峰力矩、相对峰力矩在240°/s时显著大于健将组(P<0.05),屈伸肌峰力矩比健将组由60°/s时1.02降至240°/s时0.44,下降显著(P<0.01),快速屈曲能力不足;(2)国际健将组肘关节伸肌不同速度下适应性和做功效率较健将组强,屈伸肌峰力矩比由60°/s时的1.50降至240°/s时的0.74;(3)国际健将组腕关节屈肌群峰力矩、相对峰力矩随速度的加快下降显著(P<0.05),屈伸肌峰力矩比两组在60°/s时分别为1.90和1.78并降至240°/s的1.09和0.53,健将组下降显著(P<0.05)。结论:在投掷臂三关节肌肉力量特征上,女子铅球项目国际健将在肩、肘、腕三关节屈伸力矩和功率综合分析均优于健将运动员,证明了强大的投掷臂三关节肌力是女子铅球项目取得优异成绩的根本保证。     

青年军人腰椎间盘突出症其下肢肌力等速测试分析

采用CYBEX6000型等速测力系统,对腰椎间盘突出症引起单侧下肢受累的17名男性青年军人患者,进行双下肢膝屈伸肌力的对照测试,结果表明患侧与腱侧相比,在60°/s速度测试时,绳肌和股四头肌分别平均下降了45%和31%,在180°/s时分别下降57%与35%。提示患肢屈肌力下降明显,治疗康复期内应加强绳肌群锻炼。     

前十字韧带损伤后股四头肌腘绳肌等速肌力评价(附5例报告)

用Ｃｙｂｅｘ－６０００型等速测力系统对５例前十字韧带（ＡＣＬ）损伤后患者股四头肌绳肌肌肉功能进行评价。结果表明：患膝屈伸肌群峰力矩在６０°／ｓ、１２０°／ｓ和１８０°／ｓ时均较健侧明显降低；在１８０°／ｓ时，股四头肌绳肌的总作动量、平均功率和力矩加速能量亦显著下降；绳肌股四头肌峰力矩比值（Ｈ／Ｑ）较健侧略有增高，但患者间差异较大。废用性肌肉萎缩、关节不稳及关节源性肌肉抑制可能是导致肌肉功能下降的重要原因。ＡＣＬ损伤后应强调患膝肌力训练，以增强关节稳定性，预防或延迟膝关节骨关节炎的发生；并把Ｈ／Ｑ作为肌力训练中一个评价和监测指标。     

强化循环训练对新兵膝屈伸肌功能影响的等速测试研究

目的　研究强化循环训练对新兵膝屈伸肌功能的影响。方法　 16 0名新兵进行 8周强化循环训练 ,训练前后采用Cybex 6 0 0 0型等速运动测试仪对膝屈伸肌肌力、肌爆发力及肌耐力进行等速测试并加以比较。结果　新兵训练后双膝屈伸肌的峰力矩、力矩加速能和耐力比在不同测试速度 (6 0°/s,180°/s)时有不同程度的提高 ,训练前后相比差异有统计学意义 (P <0 0 5 )。结论　 8周的强化循环训练能达到全面发展新兵膝屈伸肌肌力、肌爆发力和肌耐力的目的。     

Effect of glenohumeral position on contact pressure between the capsulolabral complex and the glenoid in free ALPSA and Bankart lesions

Purpose

Anterior shoulder dislocation is a common injury, but the optimal management of dislocation remains controversial. We hypothesized that reducing the shoulder in externally rotated position would aid the reduction in capsulolabral lesions. Thus, in this study, contact pressure between the capsulolabral lesion and the glenoid in free ALPSA and Bankart lesions was measured using a cadaver model.

Methods

In 10 specimens, the humerus was externally rotated by abduction on the coronal plane to measure the contact pressure between the capsulolabral complex and glenoid in free ALPSA and Bankart lesions using a Tekscan pressure system. Stability of the joint was confirmed using the Vicon motion analysis system.

Results

In the normal shoulder joint, the peak pressure between the subscapularis muscle and the anterior capsule according to the location of the glenohumeral joint decreased to 83.4 ± 21.2 kPa in the 0° abduction and ?30° external rotation positions and showed a 300.7 ± 42.9 kPa peak value in the 60° abduction and 60° external rotation positions. In both free ALPSA and Bankart lesions, the lowest pressure between the labral lesion and the glenoid was measured at 0° abduction and ?30° external rotation, and the highest pressure was recorded at 60° external rotation and 60° abduction.

Conclusion

The contact pressure between the capsulolabral complex and the glenoid significantly increased when the abduction and external rotation angles were increased. Based on our results, the conservative management in free ALPSA lesions would respond better than Bankart lesions.

IRB or ethical committee approval

YWMR-12-0-038.

     

Biomechanical stability of an arthroscopic anterior capsular shift and suture anchor repair in anterior shoulder instability: a human cadaveric shoulder model

It was hypothesized that an arthroscopic Bankart repair with suture anchors supplies sufficient anterior shoulder stability, which cannot be improved by an additional capsular shift. In an experimental biomechanical human cadaver study, we tested ten fresh human cadaver shoulders in a robot-assisted shoulder simulator. External rotation and glenohumeral translation were measured at 0° and 80° of glenohumeral abduction. All measurements were performed under the following conditions: on the non-operated shoulder; following the setting of three arthroscopic portals; following an arthroscopic anterior capsular shift; following a simulated Bankart lesion; and following an arthroscopic Bankart repair. The application of three arthroscopic portals resulted in a significant increase of the anterior (P = 0.01) and antero-inferior translation (P = 0.03) at 0° and 80° abduction, as well as an increase in external rotation at 80° abduction (P = 0.03). Capsular shift reduced external rotation (P = 0.03), but did not significantly decrease translation. Simulating anterior shoulder instability, glenohumeral translation significantly increased, ranging from 50 to 279% of physiological translation. Arthroscopic shoulder stabilization resulted in a decrease of translation in all tested directions to approximately physiologic levels. External rotation in 0° abduction was thus decreased significantly (P = 0.003) to an average of 19°. The study proved that an arthroscopic anterior capsular shift in a cadaveric model decreases external rotation without a significant influence on glenohumeral translation. Arthroscopic shoulder stabilization with suture anchors thus sufficiently restores increased glenohumeral translation, but also decreases external rotation in neutral abduction. An anatomic reconstruction of the Bankart lesion without overconstraining of the antero-inferior capsule should therefore be the aim in arthroscopic anterior shoulder stabilization.     

Trapezius activity and intramuscular balance during isokinetic exercise in overhead athletes with impingement symptoms

We compared normalized trapezius muscle activity and intramuscular balance ratios between overhead athletes with impingement symptoms and non-injured athletes during isokinetic abduction and external rotation movements. Thirty-nine overhead athletes with chronic impingement symptoms and 30 non-injured athletes participated in the study. Electromyographic activity of upper, middle, and lower trapezius was measured during isokinetic abduction and external rotation, using surface electrodes. The results show a significant increase of upper trapezius activity during both movements in the patient group, with decreased activity in the lower trapezius during abduction, and in the middle trapezius during external rotation. Analysis of the intramuscular activity ratios revealed muscle imbalance on the injured side of the patient group for upper/middle trapezius and upper/lower trapezius during abduction, and for all three muscle activity ratios during external rotation. These results confirm the presence of scapular muscle imbalances in patients with impingement symptoms and emphasize the relevance of restoration of scapular muscle balance in shoulder rehabilitation.     

Does adding heavy load eccentric training to rehabilitation of patients with unilateral subacromial impingement result in better outcome? A randomized, clinical trial

Purpose

To investigate superior value of adding heavy load eccentric training to conservative treatment in patients with subacromial impingement.

Methods

Sixty-one patients with subacromial impingement were included and randomly allocated to the traditional rotator cuff training (TT) group (n = 30, mean age = 39.4 ± 13.1 years) or traditional rotator training combined with heavy load eccentric training (TT + ET) group (n = 31, mean age = 40.2 ± 12.9 years). Isometric strength was measured to abduction at 0°, 45° and 90° of scapular abduction and to internal and external rotation. The SPADI questionnaire was used to measure shoulder pain and function. Patients rated subjective perception of improvement. Outcome was assessed at baseline, at 6 and 12 weeks after start of the intervention. Both groups received 9 physiotherapy treatments over 12 weeks. At home, the TT group performed traditional rotator cuff strengthening exercises 1x/day. The TT + ET group performed the same exercises 1x/day and a heavy load eccentric exercise 2x/day.

Results

After treatment, isometric strength had significantly increased in all directions, and SPADI score had significantly decreased. The TT + ET group showed a 15 % higher gain in abduction strength at 90° of scapular abduction. Chi-square tests showed patients’ self-rated perception of improvement was similar in both groups.

Conclusion

Adding heavy load eccentric training resulted in a higher gain in isometric strength at 90° of scapular abduction, but was not superior for decreasing pain and improving shoulder function. This study showed that the combination of a limited amount of physiotherapy sessions combined with a daily home exercise programme is highly effective in patients with impingement.

Level of evidence

II.     

Eccentric hip abductor weakness in patients with symptomatic external snapping hip

Symptomatic external snapping hip can be a long‐standing condition affecting physical function in younger people between 15–40 years. Gluteal weakness has been suggested to be associated with the condition. The aim of this study was to investigate whether eccentric hip abduction strength is decreased in patients with external snapping hip compared with healthy matched controls, and to examine isometric hip abduction, adduction, extension, flexion, internal rotation, and external rotation in patients with external snapping hip and matched controls. Thirteen patients with external snapping hip were compared with 13 healthy matched controls in a cross‐sectional study design. The mean age of the patients was 25.5 ± 3.4 years and the mean age of the controls was 25.6 ± 2.6 years. Eccentric and isometric strength were assessed with a handheld dynamometer, using reliable test procedures. Eccentric hip abduction strength was 16% lower in patients with external snapping hip compared with healthy matched controls (1.50 ± 0.47 Nm/kg versus 1.82 ± 0.48 Nm/kg, P = 0.01). No other strength differences were measured between patients and controls (P > 0.05). Eccentric hip abductor weakness was present in patients with symptomatic external snapping hip compared with healthy matched controls.     

Is there a relationship between tracking ability, joint position sense, and functional level in patellofemoral pain syndrome?

Purpose

This prospective cohort study investigated proprioception and motor control changes in patients with patellofemoral pain syndrome (PFPS), and how these changes related to knee function, pain, muscle strength and muscle endurance.

Methods

The study included 43 women diagnosed with unilateral patellofemoral pain syndrome. Thirty-one healthy women were recruited as control group. Peak quadriceps femoris and hamstring muscle isokinetic torques were recorded at 60 and 180°/s. Joint position sense was tested by active reproduction of joint position during horizontal squat performance. Muscle coordination and motor control ability were tested by a multi-joint lower limb tracking-trajectory test. Muscle endurance was tested using a computerized functional squat system. Severity of pain in during stair ascent/descent, squatting, and prolonged sitting with knees 90° flexed were measured using a 10 category modified visual analogue scale. Functional levels of patients were determined using Kujala patellofemoral scores.

Results

Active reproduction of joint position did not differ between PFPS and control groups. However, tracking-trajectory error was significantly higher in PFPS group than control subjects. Hamstring and quadriceps peak isokinetic torque and muscle endurance scores were significantly lower in the PFPS group. Kujala patellofemoral score displayed significant relationships with peak isokinetic quadriceps torque, knee pain, and joint position sense scores. Pain during stair descent, sitting, and quadriceps torque at 180°/s explained 57.7 % of the variation in Kujala patellofemoral score.

Conclusion

Although lower extremity joint position sense did not differ between groups, the PFPS group displayed a target-trajectory muscular coordination deficit, decreased muscular endurance, and decreased muscular strength compared to control group subjects. Pain level directly related to motor control performance while joint position sense scores did not. Knee pain and impaired strength related more to functional performance impairment than joint position sense scores in patients with PFPS.

Level of evidence

Prospective case–control study, Level III.     

Orientation feedback during simulated simple translation tests has little clinical significance on the magnitude and precision of glenohumeral joint translations

The repeatability of shoulder instability clinical examinations has been reported to be poor, producing a large range of translations. The objective of this study was to determine the effect of providing the clinician with joint orientation feedback on the magnitude and precision of glenohumeral joint kinematics. A 6-degree of freedom magnetic tracking system was used to determine the kinematics of the humerus with respect to the scapula (n=8 cadaveric shoulders). The joints were preconditioned with simple loading tests five times. At 60° of glenohumeral abduction and 0° of flexion/extension, a clinician then applied an anterior and posterior load to the humerus until a manual maximum simulating a simple translation test (STT) was achieved at 0, 30, and 60° of external rotation with and without angular orientation feedback of the humerus with respect to the scapula. The precision for the external rotation was within 4.3° for the feedback group and 17.5° for the no feedback group over all external rotations. For achieving the target external rotation of 30°, there was a significant difference in precision between the feedback and no feedback groups (p<0.05). The magnitudes of the anterior translations were 18.2±5.3, 15.5±5.1, and 9.9±5.5 mm for the feedback group and 19.3±6.6, 17.5±4.9, and 11.5±5.3 mm for the no feedback group, at 0, 30, and 60° of external rotation, respectively. There was a significant difference in the precision of anterior translation at 30 and 60° of external rotation for 4 of 8 specimens (p<0.05). Significant differences in the precision of the posterior translation was only detected at 0° of external rotation for 3 of 8 specimens (p<0.05). Based on the data obtained, providing orientation feedback to a clinician performing a simulated STT results in increased precision for not only the target external rotations but also the resulting glenohumeral translations. While providing feedback may be a necessary step to achieving precise results for experimental studies, the magnitudes of translations in the anterior and posterior directions were relatively similar for the feedback and no feedback states indicating little benefit for clinical examinations.     

The influence of foot position on lower leg muscle activity during a heel raise exercise measured with fine-wire and surface EMG

ObjectiveExercises for lower leg muscles are important to improve function. To examine the influence of foot position on lower leg muscle activity during heel raises.DesignCross-sectional laboratory study.SettingLaboratory.ParticipantsFourteen healthy men participated in this study.Main outcome measuresThe muscle activity levels of the tibialis posterior (TP), peroneus longus (PL), flexor digitorum longus (FDL) and medial gastrocnemius (MG) were measured. The heel raises consisted of three foot positions: 1) neutral, 2) 30° abduction, and 3) 30° adduction. The EMG data for five repetitions of each foot position were normalized to maximum voluntary contraction. One-way repeated measure ANOVA was employed for statistical analysis.ResultsThe muscle activity level of TP, PL and FDL was significantly different between the three foot positions during the heel raises. TP and FDL showed the highest activity level in 30° foot adduction while PL demonstrated the highest activity level in 30° foot abduction.ConclusionsHeel raises with 30° foot adduction and abduction positions can change lower leg muscle activity; These findings suggest that altering foot posture during the heel raise exercise may benefit patients with impaired TP, PL or FDL function.     

Influence of lower extremity rotation on knee kinematics in single-leg landing

ObjectivesAlthough the rotation of lower extremities has gained increasing recognition as a risk factor for anterior cruciate ligament (ACL) injury. This study clarified the influence of lower extremity rotation on the knee during single-leg landing. Design and Setting: We recruited 30 students to perform single-leg landing from a height of 30 cm with their lower extremities in neutral, and externally and internally rotated. The knee abduction, flexion angles, and abduction angular velocity were measured. Furthermore, the abduction angle was analyzed at knee flexion angles of 15°, 20°, 25°, and 30° and compared among the three conditions using a repeated measures analysis of variance with Bonferroni post hoc tests.ResultsThe maximum abduction angle was significantly greater when internally rotated than in the neutral. The maximum abduction angular velocity was significantly greater in the internally rotated compared to in the neutral. Finally, the abduction angle at a knee flexion angle of 30° was significantly greater when internally rotated compared to in the neutral.ConclusionRotation of the lower extremities affects knee kinematics, and landing on a knee that is internally rotated may increase the risk of ACL injury.