Effect of sex and menstrual cycle in women on starting speed, anaerobic endurance and muscle power.

The aim of our study was to compare the indicators of starting speed, anaerobic endurance and power in women as well as men, and to investigate whether the values of these indicators differ in women during the follicular and luteal phases of the menstrual cycle. The studied group included 16 men and 16 women. The subjects performed the 20-second maximal cycling sprint test. The men performed the test twice at 14-day intervals. The women undertook the test 4 times: twice during the middle of follicular phase and twice in the middle of luteal phase in separate menstrual cycles. Hormonal changes during the menstrual cycle do not influence anaerobic performance, starting speed or anaerobic endurance in women. Anaerobic performance in men is higher than in women with similar aerobic performance expressed as VO2max/LBM (lean body mass). A lower power decrease with time was noted for women than men, with a similar time of maintaining power in both groups. This is evidence of women's better anaerobic endurance compared to men. At the same time, the men had significantly better starting speed rates than women.

Changes in oxidative stress and acid-base balance in men and women following maximal-intensity physical exercise.

Oxidative stress may be caused by an increased rate of ATP resynthesis during physical exercise. The aim of this study was to compare changes in the prooxidant-antioxidant state of blood plasma between men and women after maximal-intensity exercise, and to assess the relationship between these changes and the value of the maximal oxygen uptake (VO(2max)) as well as between these changes and the value of post-exercise disruptions in acid-base balance. Study participants comprised 10 women (20.7 ± 0.5 years) and 10 men (22.3 ± 0.5 years) who were physically active but did not engage in competitive sports training. VO(2max) was determined via treadmill incremental test (VO(2max) relative to body mass: 44.48 ± 1.21 ml/kg/min and 59.16 ± 1.55 ml/kg/min for women and men, respectively). The level of acid-base balance indicators (ABB), lactate concentration (La⁻), the level of total oxidative status (TOS), the level of total antioxidative capacity (TAC), and uric acid (UA) concentration were measured before and after the test. An oxidative stress indicator (OSI) was also calculated. Men showed a significant post-exercise increase in the level of TOS and OSI, while women showed a significant post-exercise increase in the level of TAC. Post-exercise changes in UA concentration were insignificant. Post-exercise changes in TOC in men depended on the absolute values of VO(2max), on VO(2max)/LBM, and on post-exercise changes in La⁻ concentration.

Physiological response is similar in overweight and normoweight boys during cycling: a longitudinal study.

The purpose of this study was to determine whether metabolic cost is similar in overweight and normoweight children when workload during exercise on a cycle-ergometer is adjusted relative to an objectively determined second ventilatory threshold (VT2) or the maximal workload (Pmax). The tests were conducted every 2 years: first at the age of 10 years and the third test at around the age of 14 years. The levels of maximal oxygen consumption (VO(2)max), Pmax, and the VT2 were determined by means of graded tests on a cycle ergometer. The main test consisted of two 6-minute exercises of submaximal constant intensity (below and above VT2) performed on a cycle ergometer, with a 4-minute recovery between efforts. The workload during cycling was adjusted individually for each participant and adjusted to the values determined in the graded test: workload at VT2 and Pmax. Physiological response (absolute and relative to free-fat mass oxygen uptake, heart rate, pulmonary ventilation, tidal volume, and breathing frequency) is similar in overweight and normoweight boys when workload on a cycle ergometer is adjusted to VT2. The only significant intergroup difference was seen in relative to body mass oxygen intake.

Comparison of physiological and acid-base balance response during uphill, level and downhill running performed at constant velocity.

The purpose of this study was to compare the physiological and the acid-base balance response to running at various slope angles. Ten healthy men 22.3 ± 1.56 years old participated in the study. The study consisted of completing the graded test until exhaustion and three 45-minute runs. For the first 30 minutes, runs were performed with an intensity of approximately 50% VO2max, while in the final 15 minutes the slope angle of treadmill was adjusted (0°; +4.5°; -4.5°), and a fixed velocity of running was maintained. During concentric exercise, a significant increase in the levels of physiological indicators was reported; during eccentric exercise, a significant decrease in the level of the analyzed indicators was observed. Level running did not cause significant changes in the indicators of acid-base balance. The indicators of acid-base balance changed significantly in the case of concentric muscle work (in comparison to level running) and after the eccentric work, significant and beneficial changes were observed in most of the biochemical indicators. The downhill run can be used for a partial regeneration of the body during exercise, because during this kind of effort an improvement of running economy was observed, and this type of effort did not impair the acid-base balance of body.

Importance of the lipophilic group in carbamates having histamine H3-receptor antagonist activity.

In order to evaluate changes in the lipophilic part of designed carbamates concerning their potential histamine H3-receptor antagonist properties a new series of O-[3-(1H-imidazol-4-yl)propanol]carbamates was derived containing N-mono- or di-alkenyl, alkynyl, cycloalkyl, or double-branched alkyl substituents. The compounds were tested in vitro for their H3-receptor antagonist activity on synaptosomes of rat cerebral cortex and shared moderate to high antagonist activity in vitro. In this series 3-(1H-imidazol-4-yl)propyl N-(4-pentenyl)carbamate (4) was the most potent compound in vitro (Ki = 6.3 nM). H3-receptor antagonist activity in the central nervous system (CNS) was detected for most compounds in the in vivo H3-receptor assay based upon measurement of brain N tau-methylhistamine levels after p.o. administration to mice. The most effective carbamate in vivo, 3-(1H-imidazol-4-yl)propyl N-(allyl)carbamate (3), showed higher CNS potency (ED50 = 0.48 mg/kg p.o.) than the reference antagonist thioperamide. For some novel carbamates their histamine H1- and H2-receptor activities were determined on isolated organs of guinea-pig thereby demonstrating their high H3-receptor selectivity.