Traditional and ankle-specific vertical jumps as strength-power indicators for maximal sprint acceleration.

AIM: This study aimed to determine the demand of strength-power capabilities represented by traditional and ankle-specific vertical jump modalities ­ squat jump (SJ), counter-movement jump (CMJ), rebound-continuous jump (RJ), rebound-continuous ankle jump (AJ) ­ relative to sprint acceleration ability during the entire acceleration phase of maximal sprint. METHODS: Nineteen male sprinters performed a 60-m maximal sprint and various vertical jumps. Correlation coefficients among the vertical jump performances and between those and the 60-m sprint time and sprint acceleration at each step were calculated. RESULTS: There were significant relationships between the 60-m sprint time and SJ height, CMJ height, AJ height, and AJ index. AJ height and index had no correlation with any other jump variables. Acceleration was significantly correlated with SJ height from the 6th to the 10th steps (r=0.48-0.51) and with CMJ height from the 5th to the 11th steps (r=0.46-0.54). Acceleration was also correlated with the AJ index from the 14th to the 19th steps (r=0.48-0.54). Acceleration had no correlation with the RJ index at any step. CONCLUSION: The results suggest that the AJ allows assessment of different reactive strengths compared with traditional jump modalities. To accelerate effectively, the explosive strengths of the SJ and CMJ are important during the early stage of acceleration (from 6.6±0.4 to 17.5±0.8 m), and the reactive strength represented by the AJ is necessary during the later stage of acceleration (from 23.4±1.0 to 33.7±1.4 m). Sprinters and coaches should be aware of the different demands of strength-power capability for effective acceleration.

Association of acceleration with spatiotemporal variables in maximal sprinting.

This study clarified the association between acceleration and the rates of changes in spatiotemporal variables on a step-to-step basis during the entire acceleration phase of maximal sprinting. 21 male sprinters performed a 60-m sprint, during which step-to-step acceleration and rates of changes in step length (RSL) and step frequency (RSF) were calculated. The coefficients of correlation between acceleration and other variables were tested at each step. There were positive correlations between acceleration and the RSF up to the second step. Acceleration was positively correlated with the RSL from the 5(th) to the 19(th) step. At the third and from the 16(th) to the 22(nd) step and from the 20(th) to the 21(st) step, there was no significant correlation, but weak relationships were found between acceleration and the RSF and RSL. The results suggest that the acceleration phase can be divided into 3 sections, and for sprinting to be effective, it is important to accelerate by increasing the step frequency to the third step, increasing the step length from the 5(th) to the 15(th) step, and increasing the step length or frequency (no systematic relative importance of step length or frequency) from the 16(th) step in the entire acceleration phase.

Inhibitory effect of the new calcium antagonist AJ-2615 on progression of atherosclerosis in cholesterol-fed rabbits.

The effects of a new calcium antagonist, AJ-2615, on progression of atherosclerosis were investigated in rabbits fed a diet high in cholesterol and compared with those of prazosin, diltiazem, and their combination. In the AJ-2615 (30 mg/kg p.o. once daily) group, high cholesterol diet-induced increases in plasma concentrations of total cholesterol, free cholesterol, and phospholipid were significantly decreased. In addition, increases in aortic lipids and calcium content, as well as those in the atherosclerotic lesion area were clearly reduced by AJ-2615. On the other hand, prazosin (3 mg/kg p.o. twice daily) and diltiazem (50 mg/kg p.o. twice daily) groups displayed no such inhibitory effects. However, the group receiving the combination of prazosin and diltiazem at their respective dose levels exhibited a significant reduction in the increase in calcium content of the aorta and a slight decrease in the atherosclerotic lesion area, although there was no decrease in plasma or aortic lipid content. These results suggest that in addition to its calcium antagonistic and alpha 1-adrenoceptor blocking actions, some other yet-unidentified properties of AJ-2615 might contribute to the antiatherosclerotic effect of this agent.

Synthesis and biological activity of 11-[4-(cinnamyl)-1-piperazinyl]- 6,11-dihydrodibenz[b,e]oxepin derivatives, potential agents for the treatment of cerebrovascular disorders.

A series of 11-[4-(cinnamyl)-1-piperazinyl]-6,11-dihydrodibenz[b,e] oxepins and related compounds were synthesized and evaluated for their protective activities against complete ischemia, normobaric hypoxia, lipidperoxidation and convulsion. Structure-activity relationship studies of this series led to the finding of (E)-1-(3-fluoro-6,11-dihydrodibenz[b,e]oxepin-11-yl)-4-(3- phenyl-2-propenyl)piperazine dimaleate (50), AJ-3941 with the most appropriate property for combined pharmacological activities. Compound 50 also shows an inhibitory effect against cerebral edema as well when orally given to rats.

Effect of OP-2507, a stable prostacyclin analogue on cerebral ischemia induced by unilateral ligation of common carotid artery in gerbils.

Effects of OP-2507 [15-cis-(4-propylcyclohexyl)-16,17,18,19,20-pentanor-9-deoxy -9 alpha-nitrilo- PGF1 methylester] on cerebral ischemia induced by unilateral ligation of common carotid artery in gerbils were investigated with reference to behavioral and neuropathological changes. A good coincidence between neurological symptoms and neuropathological changes was observed in gerbils after unilateral ligation of common carotid artery as revealed by the high percentage of coincidence (90% of total animals). All gerbils which showed neurological symptoms, either circling behavior or rolling fit, had cerebral infarction in their ipsilateral hemisphere. In these animals, neuropathological changes of cerebral regions were observed in cortex, corpus callosum, hippocampus, basal ganglia, interbrain and midbrain, in contrast with medulla oblongata and cerebellum which did not show any neuropathological changes. Pretreatment with a dose range of 1-30 micrograms/kg, s.c. of OP-2507 showed a protective effect in the occurrence of neurological symptoms, such as circling behavior and rolling fit, in a dose-dependent manner. The effect of OP-2507 was also confirmed in neuropathological examination which was performed with observation of neurological deficits in the same animals. The severity of cerebral infarction of all brain regions was significantly prevented by treatment with OP-2507. The results suggested that the protective effect of OP-2507 on regional infarction gave apparent protection against the occurrence of neurological deficits for this compound.

Enhancement of ciliary action by a beta-adrenergic stimulant.

It is known that beta-adrenergic stimulants enhance mucociliary transport in the respiratory tract. The present study clearly indicated that such an enhancement resulted from not only the alteration in secretory function but also the direct stimulation of ciliated cells. However, the enhancement of ciliary beating depended on the morphological changes in ciliated cells. On the other hand, the effect of terbutaline aerosol, a beta-adrenergic stimulant, on patients with chronic sinusitis was evaluated by paranasal sinus radiography. Consequently, marked improvements in shadows were achieved after 4 weeks in 40% of the cases examined.