Hakan Karabörk

The Effect of Fatigue on the Kinematics of Free Throw Shooting in Basketball

The Effect of Fatigue on the Kinematics of Free Throw Shooting in Basketball Fatigue is an indispensible part of a basketball game which may affect an athletes shooting kinematics. Although kinematic analyses of various sports related movements were extensively done, this study is the first to consider the effects of fatigue on the kinematics of free throw shooting. After measuring the resting heart rate, ten collegiate level, male basketball players (21.8±1.6 y; 192.8±3.6 cm; 84.1±8.5 kg) were asked to perform free throws. Two successful and two unsuccessful free throws were selected. Thereafter, participants were asked to complete the fatigue protocol, which included 30m sprints and 5 vertical jumps at each end, until they reached volitional exhaustion. Additional two successful and two unsuccessful free throws were collected. All shots were recorded by using two digital cameras operating at 60 Hz and placed in a stereoscopic view. The elbow, trunk, knee and ankle joint angles were measured before and after the ball release and at the ball release point. The selected joint angles were compared between successful and unsuccessful free throws, as well as before and after the completion of fatigue protocol. The results demonstrated that fatigue did not effect free throw shooting kinematics (p>0.05) and there was no significant joint angle difference between successful and unsuccessful shots (p>0.05). This study suggested that high level athletes are able to cope with the possible detrimental effects of fatigue while performing coordinated movements such as free throw shooting.

Seasonal and spatial variability of metals concentrations in Lake Beyşehir, Turkey.

Lake Beyşehir is the largest fresh water lake and also the largest reservoir for drinking, and irrigation water in Turkey. The lake has an area of 656 km2 with an average depth of 5 m. Metal concentrations of aluminium (Al), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb) and zinc (Zn) were determined in Lake Beyşehir on 9 June and 19 August 2005, and 12 June and 22 August 2006. The water samples were collected from 40 sampling stations. The aim of this research is to determine metal concentrations and their seasonal and spatial variability in the lake. Generally, metal concentrations of Lake Beyşehir were found to decrease in the sequence of Fe > Al > Zn > Cr > Ni > Pb > Cu > Cd as 92.8, 81.8, 7.4, 2.7, 2.2, 1.9, 1.7 and 0.5 µg L−1, respectively. The results showed that the mean concentrations of the metals in the lake water did not exceed WHO (World Health Organization), US EPA (Environmental Protection Agency) or TWQCR (Turkish Water Pollution and Control Regulations) drinking water guidelines. On the other hand, maximum levels of metals sporadically exceeded these standards in some sampling stations, especially for Al, Cr, Fe, and Pb.

Selection of appropriate sampling stations in a lake through mapping

Much valuable information is obtained from water quality measurements and monitoring of lakes around the world. A powerful tool is the use of mapping techniques, as it offers potential use in water quality research. Both remote sensing techniques and traditional water quality monitoring are required to collect data at sampling stations. This study suggests another approach to determine the most appropriate distribution of sampling stations in water reservoirs that will be mapped for water quality parameters. Tests were conducted for the proposed approach for Secchi disc depth (SDD), chlorophyll-a, turbidity and suspended solids parameters in Lake Beysehir, Turkey. Results of analysis are available for a total of 30 sampling stations in August 2006. Ten sampling stations were used to model Lake Beysehir while the others were used for validation of the model. Sampling stations that offered the best representation of the lake for each parameter were determined. Then, the best representative sampling stations for all parameters in the study were determined. Moreover, in order to confirm the accuracy of these re-determined sampling stations, modelling was performed on the results of the analysis of June 2006, and it was found that the values obtained from the re-determined sampling stations were acceptable.

PHOTOGRAMMETRIC APPROACH IN DETERMINING BEAM-COLUMN CONNECTION DEFORMATIONS

In accordance with the advances in technology, displacement calculation techniques are ever developing. Photogrammetry has become preferable in some new disciplines with the advances in the image processing methods. In this study, the authors have used two different measurement techniques to determine the angles of rotation in beam-column connections that are subjected to reversible cyclic loading. The first of these is the method that is widely used, the conventional method in structural mechanics experiments, where Linear Variable Differential Transformers (LVDTs) are utilized; and the second is the photogrammetric measurement technique. The rotation angles were determined using these techniques in a total of ten steel beam-column connection experiments. After discussing the test procedures of the aforementioned methods, the results were presented. It was observed that the rotation angles measured by each method were very close to each other. It was concluded that the photogrammetric measurement technique could be used as an alternative to conventional methods, where electronic LVDTs are used.

Georeferencing of ground-based LIDAR data using continuously operating reference stations

Abstract. Terrestrial laser scanning has been used for various outdoor visualizations such as urban, construction, excavations, and land topography. Since laser scanning data have their own local coordinates in each station, a three-dimensional point cloud model of the object of interest is created in the local coordinate system by the combination of these measurements. For spatial queries and computations, the point cloud and other spatial data should be combined in a common coordinate system. In this study, a terrestrial laser scanner (TLS) and global navigation satellite system (GNSS) receiver were integrated for the registration of the laser scanner measurements into the geodetic coordinate system. Two georeferencing methods based on the continuously operating reference stations in the network Turkey (CORS-TR) were introduced. After the building was modelled by integrating the TLS and the GNSS receiver, the point cloud model that was created was registered to the international terrestrial reference frame. The registration was performed with 0.05 m root mean square error for the two georeferencing methods.

The use of stereophotogrammetry in oral surgery: Measurement of area changes after secondary epithelization and grafting vestibuloplasties

OBJECTIVE Stereophotogrammetry (SPT) is a method in which three-dimensional coordinates are calculated from multiple two-dimensional projections. The purpose of this study was to compare the surface area changes between the secondary healing and grafting vestibuloplasty techniques in the mandible by using a stereophotogrammetric technique (SPT). PATIENTS AND METHODS Thirteen patients were included in this study: six patients were managed by using full-thickness skin or palatal mucosa grafts (two full-thickness palatal mucosal grafts and four full-thickness skin grafts); the remaining seven patients, who did not accept a second surgery for graft harvesting, underwent secondary epithelization vestibuloplasties. Postoperative changes of surgical areas were measured by using SPT. STATISTICAL ANALYSES The Wilcoxon (intragroup comparisons) and Mann-Whitney U (intergroup comparisons) tests were used for analysis of data. RESULTS In the grafting vestibuloplasty group, the surface area gain was statistically significant (P < 0.05). In the secondary epithelization vestibuloplasty group, there was no significant difference (P > 0.05), with even decrease of surface area being noted in some cases. CONCLUSION SPT is a valid method for measurement of intraoral soft tissue changes.

An Examination of the Differences in the Angles Created in the Lower and Upper Extremities During Tennis Serves by Male and Female Players

The present study was conducted on 4 female and 4 male tennis players (Average age 11.6±0.7 years; height 153.2±6.9 cm; body mass index 42.0±3.9 kg; player experience 6.4±1.3 years). All the participants volunteered to participate in the study. The players hit their tennis serves at the maximum speed they could, imagining that they were in a real tennis match. The images for successful and unsuccessful tennis serves were recorded synchronously with a speed of 60 pictures/ second by using two video cameras. These recorded images were subjected to photogrammetric evaluation using Pictran software. The ankle, shoulder and elbow angles of the players were observed during the tennis serve before hitting, at the time of hitting and after hitting the ball.