A comparison of the effects of different stretching methods on flexibility, muscle activity, and pain threshold in ballet dancers; a preliminary randomized controlled trial.

BACKGROUND: The purpose of this study is to compare the effects of stretching methods on flexibility, muscle activation, and pressure pain threshold in ballet dancers, and to suggest an effective stretching method. METHODS: Thirty-three ballet dancers were randomized to the static stretching group (n = 11), muscle energy technique stretching group (n = 11), and vibration-assisted stretching group (n = 11). The angle of hip joint extension in arabesque, activation of the rectus femoris in devéloppé, and pressure pain threshold on the rectus femoris in the sitting position were measured to compare the effects of the different stretching methods. Paired t-test was used to compare the pre and post-intervention findings within each group and one-way analysis of variance to compare the difference in the amount of changes among the groups. RESULTS: The hip joint extension angles increased in all stretching methods (p < 0.05); however, vibration-assisted stretching and muscle energy technique stretching were more effective than static stretching (p < 0.05). The activation of the rectus femoris decreased in all groups (p < 0.05); however the muscle energy technique stretching group and vibration-assisted stretching group showed a significant decrease in muscle activation compared with the static stretching group (p < 0.05). The pressure pain threshold significantly improved only in the static stretching group (p < 0.05); and vibration-assisted stretching group (p < 0.05). CONCLUSIONS: Compared with static stretching and muscle energy technique stretching, vibration-assisted stretching is a beneficial method for improving flexibility, muscle activation, and pressure pain threshold in ballet dancers.

Temperature Dependent of Mitotic Interval for Grass Puffer, Takifugu niphobles.

The objective of this study was to determine the mitotic intervals (τ0) of two consecutive cell divisions and synchronous embryonic cleavage in grass puffer, Takifugu niphobles at different water temperatures (18, 20, 22, and 24℃). The color of the fertilized egg was light yellowish. The egg type was demersal and unadhesive. Egg weight was 0.09±0.002 mg. The sizes of unfertilized eggs were smaller than fertilized eggs in major axis and minor axis at 20℃ (p<0.05). The size of the fertilized egg of 18℃ water temperature group at the blastodisc stage was the smallest (p<0.05), but no significant differences were observed in the other water temperatures group except 18℃ water temperature group (p>0.05). The first cleavage stages at 18, 20, 22, and 24℃ were at 75, 90, 105, and 120 mins, respectively. As water temperature was increased, embryonic development and formation time of the first cleavage furrow were accelerated. There were negative correlation between τ0 and water temperature for grass puffer (Y=-1.225X+70.05, R2=0.988, n=10, where Y was τ0 and X was temperature). This study confirmed that successful hatching of grass puffer was related to water temperature. Chromosome manipulation will be helpful for this species using cleavage frequency and τ0.

Anesthetic Effect and Physiological Response in Olive Flounder (Paralichthys olivaceus) to Clove Oil in a Simulated Transport Experiment.

The optimum concentrations of clove oil as an anesthetic for olive flounder (Paralichthys olivaceus) and the stress response of the fish to clove oil anesthesia were determined over a range of water temperatures, and investigated in a simulated transport experiment using analysis of various water and physiological parameters. While the time for induction of anesthesia decreased significantly as both the concentration of clove oil and water temperature increased, the recovery time increased significantly (P<0.05). The plasma cortisol concentration in fish at each temperature increased significantly up to 12 h following exposure (P<0.05), then decreased to 48 h (P<0.05). The DO dissolved oxygen concentrations, pH values, and the fish respiratory frequencies decreased over 6 h following exposure to clove oil in all experimental groups (P<0.05), whereas the NH4+ and CO2concentrations in all experimental groups increased up to 6 h (P<0.05). The pH values and DO concentrations increased with increasing clove oil concentration (P<0.05) in the 6 h following exposure, and the CO2 and NH4+ concentrations and the respiratory frequencies decreased with increasing clove oil concentration (P<0.05). The results of this experiment suggest that clove oil reduced the metabolic activity of olive flounder, thus reducing NH4+ excretion and O2 consumption. In conclusion, clove oil appears to be a cost-effective and efficient anesthetic that is safe for use and non-toxic to the fish and users. Its use provides the potential for improved transportation of olive flounder.