DIFFERENCES BETWEEN MALE AND FEMALE PLAYERS IN THE SAGITTAL PLANE BIOMECHANICS DURING VOLLEYBALL SPIKE LANDING

The purpose of this study was to investigate the kinematics and kinetics differences between male and female players after a volleyball spike landing. Eight male and eight female university volleyball players were recruited to participate in this study. The kinematic and kinetic data were collected by ten Vicon cameras (300 Hz) and two force plates (1500 Hz). The Visual 3D software was used to analyze the kinematic and kinetic variables. The results indicated that male players exhibited greater peak hip flexion angle, hip range of motion and hip extensor moment compared with female players. Female players exhibited greater peak ankle dorsiflexion and ankle range of motion than male players. These differences demonstrated that male and female players performed different strategies during volleyball spike landing

THE EFFECT OF SIDE STEP ON LOWER EXTREMITY BIOMECHANICS DURING BLOCK LANDING IN FEMALE VOLLEYBALL PLAYERS

The purpose of this study was to examine the effect of block and side step block on lower extremity biomechanics during landing in female volleyball players. Eight female university volleyball players participated in this study. The kinematic and kinetic data were collected by eight Vicon cameras (250 Hz) and two force plates (1000 Hz). The Visual 3D software was used to analyze the kinematic and kinetic of block and side step block landing variables. The results showed a significantly higher knee extensor moment during side step landing than the block landing at the time of peak vertical ground reaction force and peak joint moment. It was concluded that female players displayed greater knee extensor moment during the side step before block landing that may increase the loading on the knee

Sequence Characterization of the MC1R Gene in Yak (Poephagus grunniens) Breeds with Different Coat Colors

Melanocortin 1 receptor (MC1R) gene plays a key role in determining coat color in several species, including the cattle. However, up to now there is no report regarding the MC1R gene and the potential association of its mutations with coat colors in yak (Poephagus grunniens). In this study, we sequenced the encoding region of the MC1R gene in three yak breeds with completely white (Tianzhu breed) or black coat color (Jiulong and Maiwa breeds). The predicted coding region of the yak MC1R gene resulted of 954 bp, the same to that of the wild-type cattle sequence, with >99% identity. None of the mutation events reported in cattle was found. Comparing the yak obtained sequences, five nucleotide substitutions were detected, which defined three haplotypes (EY1, EY2, and EY3). Of the five mutations, two, characterizing the EY1 haplotype, were nonsynonymous substitutions (c.340C>A and c.871G>A) causing amino acid changes located in the first extracellular loop (p.Q114K) and in the seventh transmembrane region (p.A291T). In silico prediction might indicate a functional effect of the latter substitution. However, all three haplotypes were present in the three yak breeds with relatively consistent frequency distribution, despite of their distinguished coat colors, which suggested that there was no across-breed association between haplotypes or genotypes and black/white phenotypes, at least in the investigated breeds. Other genes may be involved in affecting coat color in the analyzed yaks