Cardiac power output and its response to exercise in athletes and non-athletes.

Cardiac power output (CPO) is an integrative measure of overall cardiac function as it accounts for both, flow- and pressure-generating capacities of the heart. The purpose of the present study was twofold: (i) to assess cardiac power output and its response to exercise in athletes and non-athletes and (ii) to determine the relationship between cardiac power output and reserve and selected measures of cardiac function and structure. Twenty male athletes and 32 age- and gender-matched healthy sedentary controls participated in this study. CPO was calculated as the product of cardiac output and mean arterial pressure, expressed in watts. Measures of hemodynamic status, cardiac structure and pumping capability were assessed by echocardiography. CPO was assessed at rest and after peak bicycle exercise. At rest, the two groups had similar values of cardiac power output (1·08 ± 0·2 W versus 1·1 ± 0·24 W, P>0·05), but the athletes demonstrated lower systolic blood pressure (109·5 ± 6·2 mmHg versus 117·2 ± 8·2 mmHg, P<0·05) and thicker posterior wall of the left ventricle (9·8 ± 1 mm versus 9 ± 1·1 mm, P<0·05). Peak CPO was higher in athletes (5·87 ± 0·75 W versus 5·4 ± 0·69 W, P<0·05) as was cardiac reserve (4·92 ± 0·66 W versus 4·26 ± 0·61 W, P<0·05), respectively. Peak exercise CPO and reserve were only moderately correlated with end-diastolic volume (r = 0·54; r = 0·46, P<0·05) and end-diastolic left ventricular internal diameter (r = 0·48; r = 0·42, P<0·05), respectively. Athletes demonstrated greater maximal cardiac pumping capability and reserve than non-athletes. The study provides new evidence that resting measures of cardiac structure and function need to be considered with caution in interpretation of maximal cardiac performance.

Bradykinin type 2 receptor -9/-9 genotype is associated with triceps brachii muscle hypertrophy following strength training in young healthy men.

BACKGROUND: Bradykinin type 2 receptor (B2BRK) genotype was reported to be associated with changes in the left-ventricular mass as a response to aerobic training, as well as in the regulation of the skeletal muscle performance in both athletes and non-athletes. However, there are no reports on the effect of B2BRK 9-bp polymorphism on the response of the skeletal muscle to strength training, and our aim was to determine the relationship between the B2BRK SNP and triceps brachii functional and morphological adaptation to programmed physical activity in young adults. METHODS: In this 6-week pretest-posttest exercise intervention study, twenty nine healthy young men (21.5 ± 2.7 y, BMI 24.2 ± 3.5 kg/m(2)) were put on a 6-week exercise protocol using an isoacceleration dynamometer (5 times a week, 5 daily sets with 10 maximal elbow extensions, 1 minute rest between sets). Triceps brachii muscle volumes were assessed by using magnetic resonance imaging before and after the strength training. Bradykinin type 2 receptor 9 base pair polymorphism was determined for all participants. RESULTS: Following the elbow extensors training, an average increase in the volume of both triceps brachii was 5.4 ± 3.4% (from 929.5 ± 146.8 cm(3) pre-training to 977.6 ± 140.9 cm(3) after training, p<0.001). Triceps brachii volume increase was significantly larger in individuals homozygous for -9 allele compared to individuals with one or two +9 alleles (-9/-9, 8.5 ± 3.8%; vs. -9/+9 and +9/+9 combined, 4.7 ± 4.5%, p < 0.05). Mean increases in endurance strength in response to training were 48.4 ± 20.2%, but the increases were not dependent on B2BRK genotype (-9/-9, 50.2 ± 19.2%; vs. -9/+9 and +9/+9 combined, 46.8 ± 20.7%, p > 0.05). CONCLUSIONS: We found that muscle morphological response to targeted training - hypertrophy - is related to polymorphisms of B2BRK. However, no significant influence of different B2BRK genotypes on functional muscle properties after strength training in young healthy non athletes was found. This finding could be relevant, not only in predicting individual muscle adaptation capacity to training or sarcopenia related to aging and inactivity, but also in determining new therapeutic strategies targeting genetic control of muscle function, especially for neuromuscular disorders that are characterized by progressive adverse changes in muscle quality, mass, strength and force production (e.g., muscular dystrophy, multiple sclerosis, Parkinson's disease).

Relationship between peak cardiac pumping capability and indices of cardio-respiratory fitness in healthy individuals.

Cardiac power output (CPO) is a unique and direct measure of overall cardiac function (i.e. cardiac pumping capability) that integrates both flow- and pressure-generating capacities of the heart. The present study assessed the relationship between peak exercise CPO and selected indices of cardio-respiratory fitness. Thirty-seven healthy adults (23 men and 14 women) performed an incremental exercise test to volitional fatigue using the Bruce protocol with gas exchange and ventilatory measurements. Following a 40-min recovery, the subjects performed a constant maximum workload exercise test at or above 95% of maximal oxygen consumption. Cardiac output was measured using the exponential CO(2) rebreathing method. The CPO, expressed in W, was calculated as the product of the mean arterial blood pressure and cardiac output. At peak exercise, CPO was well correlated with cardiac output (r = 0·92, P<0·01), stroke volume (r = 0·90, P<0·01) and peak oxygen consumption (r = 0·77, P<0·01). The coefficient of correlation was moderate between CPO and anaerobic threshold (r = 0·47, P<0·01), oxygen pulse (r = 0·57, P<0·01), minute ventilation (r = 0·53, P<0·01) and carbon dioxide production (r = 0·56, P<0·01). Small but significant relationship was found between peak CPO and peak heart rate (r = 0·23, P<0·05). These findings suggest that only peak cardiac output and stroke volume truly reflect CPO. Other indices of cardio-respiratory fitness such as oxygen consumption, anaerobic threshold, oxygen pulse, minute ventilation, carbon dioxide production and heart rate should not be used as surrogates for overall cardiac function and pumping capability of the heart.

Triceps brachii strength and regional body composition changes after detraining quantified by MRI.

PURPOSE: To determine the triceps brachii functional adaptation and regional body composition changes after 12 months of detraining. MATERIALS AND METHODS: Seventeen healthy young men (22.2 ± 1.0 y, body mass index 24.9 ± 3.1 kg/m(2) ) were put in the detraining regimen for 12 months after completing a 12-week exercise protocol on isoacceleration dynamometer (5 times a week, 5 daily series with 10 maximal elbow extensions, 1 min rest between sets). Triceps brachii muscle strength was measured by isoacceleration dynamometry, using identical protocol as during the training. Muscle volumes, subcutaneous adipose tissue (SCAT), and intermuscular adipose tissue (IMAT) at mid-humerus were assessed by using MRI. RESULTS: Long-term detraining resulted in the significant decrease of 17% and 19% in endurance strength and fatigue rate, respectively. Maximal muscle strength slightly changed, and its 4% decrease was not significant. Triceps brachii volumes of both arms returned to their pretraining values (475.7 ± 54.91 cm(3) for right arm, and 483.9 ± 77.5 cm(3) for left arm). IMAT depots in upper arm significantly increased by 14% after 12 months of detraining, when compared with baseline values (P < 0.05). CONCLUSION: Long-term detraining leads to triceps brachii adaptation with endurance strength decrease, volume return to its baseline values, and significant IMAT accumulation. IMAT values after 12 months of detraining exceed baseline, pretraining values, which is significant accumulation as a result of physiologically decreased muscle activity.

The validity of estimating triceps brachii volume from single MRI cross-sectional area before and after resistance training.

The aim of this study was to determine whether triceps brachii muscle volume can be adequately estimated from a single anatomical cross-sectional area (ACSA) and can the same model be used for prediction after training. Thirty-five healthy male non-athletes (age 21.6 ± 2.5 years, body mass index 24.8 ± 3.5 kg · m(-2)) volunteered for this study. The volumes of the upper arm extensors were calculated from magnetic resonance imaging (MRI) sequence scans and regression models were developed, which were used to predict muscle volumes from single MRI cross-sectional scans taken at different points along the humerus length. The same procedure was repeated after 12 weeks of maximal resistance training of the elbow extensors. Correlation coefficients were calculated for Model A with CSA(max), humerus length (HL), and body mass index (r = 0.919), a model with CSA(50%) and HL (r = 0.922), and a model with CSA(60%) and HL (r = 0.920) (P < 0.001). The standard error of estimate for Model A, Model CSA(50%), and Model CSA(60%) was 8.0%, 7.7%, and 7.8% respectively. Thesame prediction formula can be used for the left arm (r = 0.904). If a single ACSA is used for triceps brachii volume prediction, the best fit is with Model CSA(60%) and HL, both before and after training (r = 0.941). By introducing humerus length into the calculation, we simplify the procedure for volume measurement, since it can be obtained during MRI scanning.

Analysis of anaerobic capacity in rowers using Wingate test on cycle and rowing ergometer.

The 30-s all-out Wingate test has been used in athletes of all sport specialties to measure the capacity for short duration, high power output while cycling. The aim of this study was to establish differences in measuring anaerobic capacity between the classic Wingate test on a cycling ergometer and the modified Wingate test on a rowing ergometer in rowers. A group of20 rowers was tested by both the cycle and rowing ergometers during 30s of maximum power to test anaerobic capacity and to make correlation between these tests. The parameters measured were the peak power and mean power. The peak power on the cycling ergometer was 475 +/- 75.1W and 522.4 +/- 81W (p < 0.05) on the rowing ergometer. The mean power on the cycling ergometer and the rowing ergometer was 344.4 +/- 51.1W and 473.7W +/- 67.2, (p < 0.05) respectively. The maximum values were achieved at the same time on both ergometers, but remained on the higher level till the end of the test on the rowing ergometer. By correlating the anaerobic parameters of the classic Wingate test and a modified Wingate test on the rowing ergometer a significant positive correlation was detected in the peak power (r = 0.63, p < 0.05) as well as in the mean power (r = 0.65, p < 0.05). The results show that the rowers achieved better results of the anaerobic parameters on the rowing ergometer compared to the cycling ergometer due to a better mechanical efficiency. It is concluded that the modified Wingate test on the rowing ergometer can be used in rowers for testing their anaerobic capacity as a sport specific test ergometer since it provides more precise results.

[Influence of hormonal therapy on the level of prostate specific antigen in patients with advanced prostatic cancer].

INTRODUCTION: The aim of this study was to investigate the influence of androgen blockades on prostate specific antigen (PSA) values in patients with locally advanced and metastatic prostatic cancer. MATERIAL AND METHODS: The research was conducted on 60 patients. The group of 45 patients with prostatic cancer was divided into 3 subgroups, based on the type of the applied treatment protocol (15 patients on monotherapy with luteinizing hormone-releasing hormone agonists, 15 patients on total androgen blockade and 15 patients on monotherapy with antiandrogen). The control group consisted of 15 patients with benign prostatic hyperplasia. For all patients, the values of testosterone, luteinizing hormone and prostate specific antigen were monitored before as well as after 3 and 6 months during the treatment protocol. RESULTS: All types of the applied treatment protocols in the therapy of prostatic cancer decreased the values of prostate specific antigen significantly. The application of total androgen blockade and monotherapy with luteinizing hormone-releasing hormone agonists decreased the levels of prostate specific antigen significantly in comparison with monotherapy with antiandrogen. CONCLUSION: Although prostate specific antigen is not a prostatic cancer specific parameter; the dynamics of its decrease during the therapy of androgen blockade represents a significant marker of the therapy effect.

Heart rate variability before and after cycle exercise in relation to different body positions.

The purpose of this study was to assess the effect of three different body positions on HRV measures following short-term submaximal exercise. Thirty young healthy males performed submaximal cycling for five minutes on three different occasions. Measures of HRV were obtained from 5-min R to R wave intervals before the exercise (baseline) and during the last five minutes of a 15 min recovery (post-exercise) in three different body positions (seated, supine, supine with elevated legs). Measures of the mean RR normal-to-normal intervals (RRNN), the standard deviation of normal-to-normal intervals (SDNN), the root mean square of successive differences (RMSSD) and the low-frequency (LF) and the high-frequency (HF) spectral power were analyzed. Post-exercise RRNN, RMSSD were significantly higher in the two supine positions (p < 0. 01) compared with seated body position. Post-exercise ln LF was significantly lower in the supine position with elevated legs than in the seated body position (p < 0.05). No significant difference was found among the three different body positions for post-exercise ln HF (p > 0.05). Post-exercise time domain measures of HRV (RRNN, SDNN, RMSSD) were significantly lower compared with baseline values (p < 0.01) regardless body position. Post-exercise ln LF and ln HF in all three positions remained significantly reduced during recovery compared to baseline values (p < 0.01). The present study suggests that 15 minutes following short-term submaximal exercise most of the time and frequency domain HRV measures have not returned to pre-exercise values. Modifications in autonomic cardiac regulation induced by body posture present at rest remained after exercise, but the post-exercise differences among the three positions did not resemble the ones established at rest. Key pointsWhether different body positions may enhance post-exercise recovery of autonomic regulation remains unclear.The absence of restoration of HRV measures after 15 minutes of recovery favor the existence of modifying effects of exercise on mechanisms underlying heart regulation.On the basis of discrepancies in HRV measures in different body positions pre- and post-exercise we argue that the pace of recovery of cardiac autonomic regulation is dependent on body posture.

[Application of modified Wingate anaerobic test in maximal power measurement].

INTRODUCTION: Wingate anaerobic test is an all-out test, which gives information about maximal anaerobic power. The aim of the study was to show characteristics of standard and modified versions of Wingate anaerobic test (WAnT), and to determine and explain the differences in observed parameters due to the measurement protocol applied. MATERIAL AND METHODS: The testing was conducted on 30 male non sportsmen, who performed usual everyday activities. The following parameters were measured: peak power or anaerobic power, mean power as a mean value of power during the whole test and explosive power or acceleration. Modified versions were performed with 5 s or 10 s delay of maximal cycling activity, during which the person was slowly pedaling. RESULTS: The average values of parameters Peak power and Explosive power in our participants were 622.20 +/- 134.57 W and 89.26 +/- 28.57 W/s, respectively. In modification 1 Peak Power and Explosive Power were 680.25 +/- 133.43 W and 100.60 +/- 12.77 W/s, and in modification 2 they were 685.95 +/- 135.68 W and 100.30 +/- 10.09 W/s. Significant differences were found in both parameters between the standard and modified versions, but there was no significant difference between two modified versions. The mean power parameter was not considered in the discussion, because of the fact that modified versions were shortened, and it was not a valid measurement for this parameter. DISCUSSION AND CONCLUSION: The difference between standard and modified versions can be explained by the difference between test and retest probes, and also because of modification of protocol which can partially influence the results of testing.

[Hospital morbidity and mortality of adolescents in Vojvodina].

INTRODUCTION: The aim of this study was to analyze hospital morbidity and mortality of adolescents in Vojvodina in 2004. MATERIAL AND METHODS: The analyzed data for hospital morbidity were obtained from the Reports on diseases and conditions of hospitalized patients in the Service for stationary-hospital treatment. Hospital mortality was analyzed on the basis of Documentation tables of vital statistics of Republic of Serbia. In order to have better insight into the pathology, the adolescents were divided by sex and age (the younger ones from 10-14 years, and the older ones, from 15-19 years). RESULTS: The hospital morbidity of adolescents in Vojvodina in 2004 was 47/1,000 adolescents, while in 1983 it was 53/1,000 adolescents. The most frequent indications for hospitalization of the adolescents were respiratory, digestive diseases, and injuries, poisoning and consequences of an external factor influences. The overall mortality rate was 39.68/100,000 adolescents and in 1988 44.74/100,000 adolescents. Hospital mortality rate in Vojvodina in 2004 was 16.18/100,000 adolescents and in 1986 11.65/100,000 adolescents. The male adolescents most frequently died in hospitals because of tumors, and female ones because of injuries, poisoning and consequences of external factor influences. DISCUSSION AND CONCLUSION: Morbidity structure was not changed compared to the previous period. Older and female adolescents were more frequently hospitalized. There was a decrease in adolescent mortality for 15.5% compared to the previous 15 years. Hospital mortality rate was higher than before. Older adolescents had three times the death rate of younger. Mortality rates for male adolescents were three times rates for females. Programs for adolescents' health care must be implemented fully, with engagement of whole community services, in order to prevent and cure diseases adequately and to enhance quality of life.

Maximal anaerobic power test in athletes of different sport disciplines.

The aim of this study was to investigate the values of anaerobic energetic capacity variables in athletes engaged in different sport disciplines and to compare them in relation to specific demands of each sport. Wingate anaerobic tests were conducted on 145 elite athletes (14 boxers, 17 wrestlers, 27 hockey players, 23 volleyball players, 20 handball players, 25 basketball players, and 19 soccer players). Three variables were measured as markers of anaerobic capacity: peak power, mean power, and explosive power. The highest values of peak power were measured in volleyball 11.71 +/- 1.56 W.kg and basketball players 10.69 +/- 1.67 W.kg, and the difference was significant compared with the other athletes (p 0.05). The measured results show the influence of anaerobic capacity in different sports and the referral values of these variables for the elite male athletes. Explosive power presented a new dimension of anaerobic power, i.e., how fast maximal energy for power development can be obtained, and its values are high in all sports activities that demand explosiveness and fast maximal energy production. Coaches or other experts in the field could, in the future, find useful to follow and improve, through training process, one of the variables that is most informative for that sport.

Changes of functional status and volume of triceps brachii measured by magnetic resonance imaging after maximal resistance training.

PURPOSE: To evaluate the effect of 6-week self-perceived maximal resistance training on muscle volume utilizing magnetic resonance imaging and maximal, average, and endurance strength of the elbow extensors and to assess the relationship between muscle strength and volume before and after the training. MATERIALS AND METHODS: This was a prospective blinded study. A total of 15 healthy untrained men, aged 22.5+/-3.7 years (mean+/-SD), were engaged in elbow extensor training using isoacceleration dynamometry for 6 weeks with a frequency of five sessions per week (five sets of 10 maximal voluntary contractions, 1-minute rest period between each set). Prior to and after the training, cross-sectional magnetic resonance images of the upper arm were obtained and muscle volumes were calculated using the truncated cone formula. RESULTS: Average, maximal, and endurance strength of the upper arm extensors increased significantly by 43%, 15%, and 56%, respectively. The volume of triceps brachii increased in both arms (P<0.05): right from 456.9+/-113.8 cm3 to 475.8+/-100.9 cm3 and left from 444.3+/-121.9 cm3 to 468.4+/-110.4 cm3, or 5%. Maximal and average strength correlated significantly with muscle volume before and after the training. CONCLUSION: A specific 6-week resistance training protocol resulted in muscle strength improvement, together with increase in triceps brachii muscle volume, as demonstrated by volumetric imaging.

Motivation and motoric tests in sports.

Motivation in sport performance has been an interesting topic for many investigators during the past decade. This area can be considered from different viewpoints: motivation for participation in sport activity, achievement motivation, competitiveness etc. Motivation plays an important role in all out tests, as well as in sport activities and at all levels of competition. Motivation climate, or positive social environment may influence and modulate motivation of individuals involved in sports. Experience has shown that conventional encouragement and feedback during the test may affect its outcome. According to Wingate research team recommendations, verbal encouragement, as a motivation factor, was given to all examined subjects during Wingate anaerobic test, which is considered the most reliable test for assessing anaerobic capacity. The investigated group consisted of 30 young men--medical students, who were not actively involved in any programmed sport activity. The investigated group included second-year students of the Faculty of Medicine in Novi Sad chosen by random sampling. The Wingate anaerobic test was performed in all subjects, and changes of parameters when test was performed with verbal encouragement, were recorded The results show statistically significant increase of Wingate test parameters when conducted with verbal encouragement: anaerobic power (622/669 W); relative anaerobic power (7.70/8.27 W/kg); slope of the power (95.5/114 W/s); relative slope of the power (1.18/1.40 W/s/kg); anaerobic capacity (12.7/13.2 kJ) and relative anaerobic capacity (158/164 J/kg).

[Event-related potentials following exercise bouts of different intensity].

INTRODUCTION: A number of articles on physical activity analyze the effects of acute bouts of physical exercise on the whole body. These experiments mainly include questionnaires and measurements of reaction time. The use of event-related potentials in laboratories for functional diagnostics is only of recent date. The aim of this experiment was to give insights into the impact of physical activity of different intensity on the amplitude and latency of P300 cognitive potentials. MATERIAL AND METHODS: After recording cognitive event-related potentials in 17 young (21.6+/-1.07 yrs) healthy adults (at Fz and Cz), the participants underwent a controlled bicycle ergometer exercise. Each exercise lasted 10 minutes, with successive increase in the intensity to 60%, 75% and 90% of the maximum pulse rate and maintaining this level of intensity for six minutes. Immediately after each bout of exercise, event-related potentials were recorded. RESULTS: The amplitude of the P300 wave, following exercise intensity at 75% of the maximum pulse (Pmax) (Fz 15.00+/-4.57, Cz 18.63+/-8.83 mV ) was statistically higher (p<0.05) than the amplitude of the P300 at rest (Fz 11.21+/-4.15 mV; (Cz 13.40+/-8.04 mV), at 60% (Fz 11.86+/-5.11 mV; Cz 14.54+/-8.06 mV) and at 90% of maximum pulse (Fz 13.26+/-4.73 mV; Cz 14.91+/-8.91 mV). There were no statistically significant differences (p>0.05) between amplitudes at 60% of Pmax and values obtained at rest and at 90% of Pmax. Also, no statistically significant differences were recorded (p>0.05) among the latencies of P300 recorded at rest (Fz 323.57+/-3.24 ms; Cz 323.57+/-13.24 ms) and at 60% of Pmax (Fz 321.14+/-22.38 ms; Cz 321.86+/-22.88 ms), at 75% of Pmax (Fz 321.50+/-16.67 ms; Cz 322.50+/-14.60 ms) and at 90% of Pmax (Fz 326.29+/-7.85 ms; Cz 325.43+/-7.63 ms). DISCUSSSION AND CONCLUSION: Physical activity has a positive impact on cognitive functions. At intermediate intensities, the amplitude of P300 increases, but at submaximal intensities it decreases to values obtained at rest. However, the latency of P300 did not show a statistically significant change after different intensities of exercise.