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.

The aim of this study was to determine morphological and functional changes of the elbow extensor muscles in response to a 12-week self-perceived maximal resistance training (MRT). Twenty-one healthy sedentary young men were engaged in elbow extensor training using isoacceleration dynamometry for 12 weeks with a frequency of five sessions per week (five sets of ten maximal voluntarily contractions, 1-min rest period between each set). Prior to, at 6 weeks and after the training, a series of cross-sectional magnetic resonance images of the upper arm were obtained and muscle volumes were calculated. Maximal and endurance strength increased (P<0.01) by 15% and 45% at 6 weeks, and by 29% and 70% after 12 weeks compared with baseline values, while fatigue rate of the elbow extensors decreased by 67%. The volume of triceps brachii increased in both arms (P<0.01) by 4% at 6 weeks, and by 8% after 12 weeks compared with baseline values (right arm--from 487.4 ± 72.8 cm³ to 505.8 ± 72.3 cm³ after 6 weeks and 525.3 ± 73.7 cm³ after 12 weeks; left arm--from 475.3 ± 79.1 cm³ to 493.2 ± 72.7 cm³ after 6 weeks and 511.3 ± 77.0 cm³ after 12 weeks). A high correlation was found between maximal muscle strength and muscle volume prior (r² = 0.62) and after (r² = 0.69) the training (P≤0.05). A self-perceived MRT resulted in an increase in maximal and endurance strength. Morphological adaptation changes of triceps brachii as a result of 12-week specific strength training can explain only up to 26% of strength gain.

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.

Context: As a result of the adaptation process, some functional properties show different functions over time during strength training. Muscle strength and fatigue may show different adaptation patterns in reaching the improvement plateau after several weeks of training.Objective: To follow muscle endurance and fatigue values during resistance training of the elbow extensors in young nonathletes.Design: Descriptive laboratory study. Setting: Controlled laboratory.Patients or Other Participants: Nineteen healthy young nonathletes (age ¼ 21.0 6 1.1 years; body mass index ¼ 25.2 6 2.9 kg/m 2 ). Intervention(s): Triceps brachii resistance training was performed on the isoacceleration dynamometer for 10 weeks (frequency ¼ 5 times a week, 5 sets of 10 maximal elbow extensions, 1-minute resting period between sets).Main Outcome Measure(s): Measurements of endurance strength and fatigability were conducted using the same equipment, and endurance strength (ES), fatigue rate (FR), and decrease in strength (DS) were defined.Results: All measured values for triceps brachii strength changed after training (ES increased by 57%, FR decreased by 68%, and DS improved by 59%; P , .001). No correlation was found between ES and the fatigability values-FR and DS (r 2 ¼ 0.37 for FR and r 2 ¼ 0.04 for DS; P . .05). The FR and DS trends showed specific functions, which reached a plateau after 4 weeks of training, and we found no further weekly changes in these values as the training continued. As an adaptation to exercise, ES showed a continuous, yet not linear, increase.Conclusions: Fatigability in the triceps brachii decreased in the first 4 weeks of training. After that period, muscle functional properties improved as a result of increased endurance.Key Words: conditioning, upper extremity, athletes Key PointsFatigue of the triceps brachii muscle decreased during the first 4 weeks of strength training. Decreased strength of the triceps brachii muscle during multiple contractions plateaued after 4 training weeks. Further improvement in muscle functional properties was a result of increased endurance.S trength training leads to functional and morphologic adaptations of skeletal muscles. 1-5 Different effects are expected from different intensities, frequencies, and durations of a training protocol. A greater increase in strength is accomplished with maximal loads, a smaller number of repetitions, and shorter rest periods between sessions. More repetitions in a series with smaller loads and longer interseries intervals increase endurance.6-8 Surely, the adaptation effects are also closely related to age, genetic predisposition, muscle or fiber types, previous training history, and hormonal or other influences. 8,9 In any case, the objective of a training program is to increase the function of skeletal muscles, which relates not only to maximal muscle strength and power but also to endurance and fatigue. Endurance is the ability of a muscle to maintain its function throughout time and multiple contractions. Muscle endurance can be expre...

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 Ϯ 3.7 years (mean Ϯ 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 Ͻ 0.05): right from 456.9 Ϯ 113.8 cm 3 to 475.8 Ϯ 100.9 cm 3 and left from 444.3 Ϯ 121.9 cm 3 to 468.4 Ϯ 110.4 cm 3 , 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.