Proprioception, encompassing the submodalities of kinesthesia and joint position sense, is important in the maintenance of joint stability, especially in the shoulder. The purpose of this study was to examine the effects of plane and elevation angle on unconstrained shoulder joint position sense. Twenty-two subjects (12 male, 10 female) without a history of shoulder pathology were recruited from a university campus. Subjects attempted to replicate, with respect to plane and elevation angles, various target positions. Target positions consisted of five plane angles at 908 of arm elevation and five arm elevation angles in the scapular plane. All target positions were tested twice to assess the reliability of the measurement. Intraclass correlation coefficients were generally low across target positions, possibly owing to the novelty and demanding nature of the task. No differences in repositioning errors were observed between plane angles (p ¼ 0.255). Repositioning errors decreased linearly as the elevation angle increased from 308 to 908 (p ¼ 0.007) and increased again from 908 to 1108 of elevation (p ¼ 0.029). Our results suggest that unconstrained joint position sense may be enhanced with increased muscular activation levels. Further, afferent feedback from musculotendinous mechanoreceptors may dominate over that from capsuloligamentous sources in unconstrained movements. ß

The push-up is a popular upper-extremity weight-bearing exercise. However, limited information is available regarding its effectiveness. Much of the past research has focused on muscle activation levels, whereas very little has examined the forces encountered during push-up variants. The purpose of the present study was to examine the effect of position within the range of motion on the percentage of body mass (BM) supported by the upper extremities during the traditional and modified (knees-down) push-up. Twenty-eight highly strength-trained male subjects were positioned with their hands on a force platform in 4 static positions, consisting of the up and down position in both the traditional and modified push-up exercise. The performance measures included the average vertical ground reaction force (GRF), expressed as a percentage of BM, supported in each of the 4 static positions and the percentage of change between the up and down positions in each push-up exercise. In both the traditional and modified push-ups, subjects supported less weight in the up vs. the down position. The percentage change in % BM from the up to the down position was greater in the modified push-up variant. The pattern of resistances to the push-up exercises observed in this study may be a result of differing moment arms between the support surface contact point (knees or feet) and the hands. These results may be useful in prescribing programs for strengthening and/or rehabilitation for both the prime movers and stabilizers of the upper extremity. Further, range of motion may need to be altered to accommodate strength differences in beginners and clients rehabilitating from injury.

. Ms Aarseth is now with Black Hills Surgical Hospital, Rapid City, SD.Context: Joint position sense (JPS) is a key neuromuscular factor for developing and maintaining control of muscles around a joint. It is important when performing specialized tasks, especially at the shoulder. No researchers have studied how Kinesio Tape (KT) application affects JPS.Objective: To investigate the effects of KT application and no tape on shoulder JPS at increasing shoulder elevations in athletes.Design: Cross-sectional study. Setting: University laboratory. Patients or Other Participants: A total of 27 healthy athletes who did not participate in overhead sports (age ¼ 20.44 6 1.05 years, height ¼ 175.02 6 11.67 cm, mass ¼ 70.74 6 9.65 kg) with no previous pathologic shoulder conditions volunteered for the study. All participants were from 1 university.Intervention(s): Shoulder JPS was assessed at increasing elevations with and without KT application. Participants attempted to actively replicate 3 target positions with and without the KT and without visual guidance. Main Outcome Measure(s):We examined absolute and variable repositioning errors at increasing shoulder-elevation levels with and without KT application.Results: Data revealed an interaction between tape and position for absolute error (F 2,52 ¼ 4.07, P ¼ .02); simple effects revealed an increase in error, with KT demonstrating a 2.658 increase in error at 908 of elevation compared with no tape (t 26 ¼ 2.65, P ¼ .01). The effect size was medium (x 2 ¼ .135). Variable error showed no interaction of tape and position (F 2,52 ¼ .709, P ¼ .50). Further analysis of simple effects was not needed. However, we still calculated the effect size and observed small effect sizes for tape (x 2 ¼ .002), position (x 2 ¼ .072), and tape by position (x 2 ¼ .027). Conclusions: At 908 of elevation, shoulder JPS was impaired by the application of KT.

Background: Tightness of hip flexor muscles has been recognized as a risk factor for various musculoskeletal injuries in the lower extremities. Purpose:The purpose of this study was to examine the acute effects of two hip flexor stretching techniques (dynamic and hold-relax proprioceptive neuromuscular facilitation, HR-PNF) on hip extension (ROM), knee joint position sense (JPS) and balance in healthy college age students who exhibit tightness in hip flexor muscles.Study Design: Pretest-posttest randomized experimental groups.Methods: Thirty-six healthy college age students (mean = 22.37 years) with tight hip flexors participated in this study. Hip extension ROM, knee joint position sense and dynamic balance were tested pre-and post-stretching using a digital inclinometer, an iPod touch and the Y-Balance test, respectively. Subjects were randomly divided into dynamic and HR-PNF stretching groups. Three-way mixed analysis of variance was utilized to explore if an interaction existed between the groups in tested variables.Results: There was a significant effect of time on hip extension ROM in both groups (p < 0.001). There was also a significant effect of stretch type on hip extension ROM (p = 0.004) favoring hold-relax over dynamic stretching group. There was a non-significant effect of time on mean knee joint position replication error in both groups. There was a significant main effect of time on the Y-Balance test's mean distance of reach to posteromedial and posterolateral directions (p < 0.001). There was also a significant main effect of directions of reach on distances achieved (p < 0.001) favoring posterolateral over posteromedial, and the latter over anterior direction. Conclusions:The results of this study demonstrated the effectiveness of both HR-PNF and dynamic stretching techniques which resulted in a significant acute improvement in hip extension ROM and dynamic balance measures, with HR-PNF being more effective than dynamic stretch. However, there were no significant improvements in knee joint position replication over time in either stretching group.

No abstract