The aim of this study was to examine whether the intracyclic velocity variation (IVV) was lower in elite swimmers than in beginner swimmers at various velocities, and whether differences may be related to arm coordination. Seven elite and nine beginner male swimmers swam front crawl at four different swimming velocities (maximal velocity, 75%, 85%, and 95% of maximal swimming velocity). The index of arm coordination (IDC) was calculated as the lag time between the propulsive phases of each arm. IVV was determined from the coefficient of variation of horizontal velocity within one stroke cycle. IVV for elite swimmers was significantly lower (26%) than that for beginner swimmers at all swimming velocities (p<0.01, 7.28
1.25% vs. 9.80
1.70%, respectively). In contrast, the IDC was similar between elite and beginner swimmers. These data suggest that IVV is a strong predictor of the skill level for front crawl, and that elite swimmers have techniques to decrease IVV. However, the IDC does not contribute to IVV differences between elite and beginner swimmers.
Objective: Rotator cuff tears can influence shoulder kinematics and severely impair function. However, there have been no studies on three-dimensional (3D) shoulder kinematics in massive rotator cuff tear (MRCT) patients. Hypothesizing that MRCT patients could demonstrate significantly changed scapular kinematics during arm elevation in the scapular plane, we compared 3D scapular kinematics in the scapular plane between MRCT patients and healthy elderly subjects.
Methods:We assessed 15 shoulders of 11 MRCT patients and 16 shoulders of 16 healthy subjects. With the subjects seated, we used an electromagnetic tracking system to calculate the upward rotation, posterior tilt, and internal rotation of the scapula at 10° increments from 30° to 120° with respect to the thorax. We performed two-way analysis of covariance with the initial position of the scapular motion as the covariate and performed multiple comparisons using the Bonferroni method. Results: MRCT patients exhibited significantly higher scapular upward rotation than did the healthy subjects (P < 0.05). There were no significant differences between groups with regard to posterior tilt and internal rotation. Conclusions: This study indicated that when MRCT patients elevated their arms, they exhibited a significantly higher scapular upward rotation at low-to mid-range elevations compared with that of healthy subjects. This difference may have resulted from a compensatory effect in response to the decreased elevation torque caused by the loss of rotator cuff function. These results may assist rehabilitation strategies to improve active arm elevation in MRCT patients.
Tendencies in rhythmic gymnastics were investigated, to obtain basic information about the of performance gymnastics. Participants were gymnasts (N = 27: 22 experienced gymnasts and 5 junior gymnasts) that participated in individual exercises at the 66th Japan rhythmic gymnastics competition. We examined four exercises, hoop, ball, clubs, and ribbons. For each exercise, we recorded the time and the number of "Body Difficulties" and the time taken to execute one Difficulty. Moreover, we recorded the time for each movement. Then, we used these values to examine the reliability and validity of the chronological index of a composition. The correlation between each index and the Difficulty score was calculated for each apparatus. Based on the scoring rules for "Difficulty", the duration of Body Difficulty was defined from preparation to the end of each Difficulty. We conducted a two-way analysis of variance (ANOVA) with the apparatus and movements as independent variables, which indicated a significant interaction effect in the number of Difficulties that were executed. Moreover, there was a significant main effect of apparatus and movement. Furthermore, performance time showed significant interaction effects (all p < 0.01). However, no significant interaction was observed for the time for executing each Difficulty.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.