Abstract.[Purpose] The purpose of this study was to investigate the effects of Tai Chi (TC) based exercise on dynamic postural control when people with mild or moderate Parkinson's disease (PD) initiate gait.[Subjects] Ten people with PD, who ranged in age from 70 to 84 years, volunteered to participate in a 12-week intervention of TC exercise.[Methods] Participants with PD were tested pre-and post-intervention in a task in which they were instructed to initiate gait from the position of quiet stance. Participants with PD were trained with TC exercise that emphasizes a shift in weight bearing from bilateral to unilateral support, challenging postural stability, three times per week over a period of 12 weeks. Differences between pre-and post-test in COP displacement in the anteroposterior (A-P) and mediolateral (M-L) directions were assessed using two force plates.[Results] After practicing the TC exercise, participants with PD significantly increased A-P and M-L displacement of the COP.[Conclusion] TC exercise increased COP displacement in the A-P and M-L directions, thereby improving participants' ability to generate momentum to initiate gait and maintain lateral stability. The findings of this study support the use of TC exercise as an effective and safe rehabilitation strategy for some individuals with PD.

[Purpose] The purpose of this study was to examine the effects of Tai Chi (TC)-based exercise on dynamic postural control during obstacle negotiation by subjects with mild or moderate Parkinson’s disease (PD). [Subjects] Twelve subjects (mean age, 65.3±6.1 years) diagnosed with idiopathic PD were enrolled for this study. [Methods] All the subjects were tested a week before and 12 weeks after the initiation of the TC exercise. In the test, they were instructed to negotiate an obstacle from the position of quiet stance at a normal speed. They were trained with TC exercise that emphasized multidirectional shift in weight bearing from bilateral to unilateral support, challenging the postural stability, three times per week for 12 weeks. Center of pressure (COP) trajectory variables before and after TC exercise were measured using two force plates. [Results] A comparison of the results between pre- and post-intervention showed a statistically significant improvement in anteroposterior and mediolateral displacement of COP. [Conclusion] Twelve weeks of TC exercise may be an effective and safe form of stand-alone behavioral intervention for improving the dynamic postural stability of patients with PD.

Background: American Society for Bone and Mineral Research recommend the use of intramedullary reconstruction of full length-nail for atypical subtrochanteric femoral fracture (ASFF). However, there is no study on the incidence of the ipsilateral femoral fracture after index operation of ASFF, and full-length nail has disadvantage as iatrogenic fracture and leg length discrepancy (LLD). The aim of this study was to investigate the incidence of ipsilateral secondary fracture after using partial-length nail, and to compare the outcomes on surgery of ASFF between partial length-nails and full length-nails. Methods: Forty-five consecutive fractures with ASFFs which had undergone intramedullary fixation using cephalomedullary nail between 2011 and 2018 were enrolled. The 45 cases were grouped based on nail length into the partial-length nail group (n =26) and the full-length nail group (n=19). Ipsilateral secondary fracture, time to union, intraoperative iatrogenic fracture, metal failure, LLD, operative duration, and post-operative 24-hr blood loss were investigated. Results: There was no ipsilateral secondary fracture after index operation. There were no statistically significant differences between the partial-length nail and full-length nail groups in the time to union, LLD, and post-operative 24-hr blood loss (P=0.427, 0.478, and 0.228, respectively). Operative duration showed statistically significant difference between 2 groups (P=0.034). Metal failure were occurred in 1 (3%) case of the partial-length nail group and 2 (10%) cases of the full-length nail group. Iatrogenic fractures during nail insertion occurred in 2 (7%) cases of the partial-length-nail group and 3 cases (15%) of the full-length nail group. Conclusions: Although large scale studies are required, our study indicate that full-length nails are not usually required for the treatment of ASFF.

Purpose: Certain pitching mechanics is thought to lead pitchers in danger of surgical risk and decrease performance. The objective of this study is to analyze the effect of shoulder hyperabduction position during early cocking phase in association with surgical risk and performance in professional baseball players. Methods: From 2009 to 2013, total of 93 candidates reached minimum inning qualification. After exclusion criteria (overlapped players, foreign players, age over 31 years, proceed to other league and retirement), 19 players were analyzed with slow-motion pitching video for hyperabduction of the shoulder and hyperpronation of forearm in cocking-phase. Also players were analyzed with innings pitched, earned run average (ERA), walks and hits divided by innings pitched (WHIP) and surgical history with database offered by official Korean Baseball Organization website. Results: Out of total 19 players, nine players had hyperabduction arm movement and 10 players did not. Group with hyperabduction had average age of 24.3 years old, average inning/ERA/WHIP for 5 years were 55 innings/yr, 6.52 ERA/yr and 1.33 WHIP/yr, respectively, and seven players (77%) had surgeries eventually. Group without hyperabduction arm movement had average age of 25.4 years old; average inning, ERA/WHIP for 5 years were 127 1/3 innings/yr, 4.84 ERA/yr, and 1.32 WHIP/yr, respectively and five players (50%) went for surgeries. Player performance (ERA, p=0.66; WHIP, p=0.14) was not statistically influenced by the certain arm position at cocking phase but average inning pitched was statistically affected (p＜ 0.01). Conclusion: Hyperabduction of shoulder in early cocking phase of throwing motion does not lead to decrease in performance (ERA, WHIP) but will result in tremendous decline of average IP. Also, risk of surgery is not associated to hyperabduction motion of the shoulder.

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