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The abstract is available here: https://uscholar.univie.ac.at/o:996089

Ozbar, Nurper/0000-0003-0931-5263; OZBAR, NURPER/0000-0003-0931-5263 WOS: 000432485600007 Introduction and objectives: Elastic resistance has been commonly used in the therapeutic and fitness setting. However, the effects of a strength training program using elastic resistance exercises to the explosive power and spike speed, which are very important elements for successful volleyball practice, has not been clearly demonstrated. Therefore, the aim of this study was to establish the effects of 8-week TheraBand training protocols on the development of spike speed, counter movement jump (CMJ) height, peak power and speed of upper limb performance of young female volleyball players. Methods: The participants consists of 20 competitive female volleyball players who regularly train at the same team and aged 15-17 years (age 16.2 +/- 0.7 years). All the players were tested for spike speed, CMJ height, peak power and speed of upper limb performances before and after 8-week training program. The players were divided into Thera-Band Training Group (TTG; n=10) and Control Group (CG; n=10). Both groups continued technical and tactical volleyball training together 3 days (120 min. d.-1) a week. Additionally, TTG attended Thera-Band training program through 8-week, 2 days per week and 2 sessions (60 min. d.-1). Results: The findings of the study showed significant change in CMJ height, peak power and spike speed at the end of 8-week. TTG significantly (p = .001) improved CMJ height, peak power and spike speed, whereas the CG showed significant changes only CMJ height and peak power (p = .05) at the end of 8week. The effect of resistance exercises was significantly higher as compared to the control group (p < .05). Results demonstrated that the TTG players showed greater improvements in CMJ height (d = 1.31, moderate effect size), and spiking speed (d = 2.93, large effect size) performance than CG. Conclusion: It can be concluded that supervised Thera-Band training contributed development of the performance of spike speed mostly and CMJ height and peak power of lower extremities in young female volleyball players. Due to its effectiveness on muscular performance, the Thera-Band training model can be recommended to the coaches and players in additional to the regular technical training.

International audience; A Paleoarchean impact spherule‐bearing interval of the 763 m long International Continental Scientific Drilling Program (ICDP) drill core BARB5 from the lower Mapepe Formation of the Fig Tree Group, Barberton Mountain Land (South Africa) was investigated using nondestructive analytical techniques. The results of visual observation, infrared (IR) spectroscopic imaging, and micro‐X‐ray fluorescence (μXRF) of drill cores are presented. Petrographic and sedimentary features, as well as major and trace element compositions of lithologies from the micrometer to kilometer‐scale, assisted in the localization and characterization of eight spherule‐bearing intervals between 512.6 and 510.5 m depth. The spherule layers occur in a strongly deformed section between 517 and 503 m, and the rocks in the core above and below are clearly less disturbed. The μXRF element maps show that spherule layers have similar petrographic and geochemical characteristics but differences in (1) sorting of two types of spherules and (2) occurrence of primary minerals (Ni‐Cr spinel and zircon). We favor a single impact scenario followed by postimpact reworking, and subsequent alteration. The spherule layers are Al2O3‐rich and can be distinguished from the Al2O3‐poor marine sediments by distinct Al‐OH absorption features in the short wave infrared (SWIR) region of the electromagnetic spectrum. Infrared images can cover tens to hundreds of square meters of lithologies and, thus, may be used to search for Al‐OH‐rich spherule layers in Al2O3‐poor sediments, such as Eoarchean metasediments, where the textural characteristics of the spherule layers are obscured by metamorphism.