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Examines the maximal voluntary peak torques of the quadriceps and hamstring muscles and the torque ratio between these muscle groups in basketball players and soccer players participating in teams of different divisions. Peak torque values relative to body weight; H/Q ratio of basketball and soccer players.

Aim: The purpose of this study was to investigate the effects of partial passive stretching (PPS) on peak torque (PT) and joint range of motion (ROM) in healthy subjects., Methods: Twenty-two males (mean age 20.4±1.0 yrs, height 181.1±4.2 cm and weight 75.8±6.8 kg) participated in the study. Quadriceps and hamstrings PT at different angular velocities was obtained on an isokinetic dynamometer. Standing leg method hop was tested for the stretched and unstretched leg. Each subject performed PPS for 20 seconds. The stretching procedure was repeated 5 times for each muscle group. The whole stretching program lasted for 6 minutes and 20 seconds followed by 5 seconds resting period., Results: Directly after the stretching procedure significant increases were observed of PT in quadriceps and hamstrings, however, only at 300o.s⁻¹ (P<0.05). Joint ROM was increased in all subjects (P<0.05). The distance in single length hop was increased significantly in the stretched leg following stretching (P<0.05). No changes were observed in the unstretched leg., Conclusion: Our results indicated that the PPS altered ROM, maximal concentric isokinetic strength at high angle velocities and single length hop only for the stretched leg. These findings suggest that PPS may be an effective technique for enhancing muscle performance.

Aim: To determine and compare the erythropoietic response and exercise performance of adolescent cross-country skiers, as a result of "living high-training high" (HH) and "living high-training low" (HL)., Methods: Nine female and six male adolescent cross-country skiers volunteered to participate in separate trials. In the first trial (HH), the skiers lived and trained for 21 days at 1550-2050 m, while in the second trial (HL) they trained near sea level (450-500 m) but resided at 1550 m. All participants underwent maximal cycle ergometer tests for the determination of VO2max and cardiorespiratory parameters via an open circuit system at sea level before ascent to altitude, and 1-2 days after descent from altitude. Blood samples were drawn prior to and immediately after maximal cycle exercise testing, at sea level prior to ascent, on days 1 (D1) and 21 (D21) at altitude (1740 m), and 1-2 days post-altitude, for the determination of serum erythropoietin (EPO) concentration, haemoglobin (Hb), hematocrit (Ht), and red blood cell (RBC) volume., Results: The results showed that both boys and girls cross-country skiers, significantly improved their sea level VO2max after 21 days of living at moderate altitude and training near sea level., Conclusion: The present study demonstrates that living at moderate altitude, 1550-2050 m and training low, near sea level (450-500 m) significantly increases VO2max and RBC mass for both boys and girls. Results indicate that applying the training concept "living high - training low" in adolescent athletes may improve their endurance performance.

Aim: The aim of the present study was to examine the adaptation of myosin heavy chain (MHC) isoforms, capillary density and fiber cross sectional area (CSA) of deltoid muscle in adolescent and adult elite Greco-Roman wrestlers., Methods: Eighteen Greco-Roman wrestlers were divided into two groups: adolescents included 10 athletes (group A) between 14-18 years of age (15.4+/-1.3 yrs) and adults included 8 athletes (group B) between 20-27 years (23.5+/-2.6 yrs). Histochemical analyses were used to determine the muscle fiber type distribution and the muscle fiber cross sectional area. MHC isoform composition was determined with protein electrophoresis, while capillary density (capillary to fiber ratio and capillaries per mm2) analysis was performed with a-amylase Periodic and Schiff staining., Results: Adolescents demonstrated a significantly higher percentage of type I fibers (P<0.05) and type I fiber area (P<0.05) compared to the adults. The percentage of type IIa fiber area were significantly higher in adult wrestlers (P<0.05). MHC I isoforms was significantly higher in adolescents (P<0.05), whereas the MHC isoforms of IIa and IIx did not differ between groups. The capillary density (mm2) were significantly higher (P<0.05) in adolescents compared to adults., Conclusion: Our findings suggest that the observed muscle fiber profile in the deltoid muscle of wrestlers may represent an adaptation based on the mechanical and biochemical demands of the long-term training. Such adaptations are linked to the specific characteristics of the training program, the level and the previous training experience of the wrestlers.

Aim: The purpose of this study was to examine the effects of specific inspiratory muscle training (IMT) on inspiratory muscle strength, maximal oxygen uptake (VO2max), maximal lactate accumulation (Lmax), dyspnea sensation and rowing performance in rowers., Methods: Ninteen well-trained rowers were divided into two groups: IMT (T) and control (C). The T group, in addition to their daily rowing practice, performed IMT by means of a threshold inspiratory muscle trainer for approximately 0.5h.d(-1), 5 times a week for 6 weeks. The C group participated only in their regular daily rowing training. Prior to the initiation and at the completion of the 6-week IMT program, both groups underwent an incremental treadmill run test to determine VO2max. Maximum inspiratory mouth pressure (PImax) was measured at rest and following the VO2max test. On a separate occasion, rowing performance was evaluated by a 2000 m all-out effort on a rowing ergometer. Dyspnea sensation was assessed by a modified Borg scale and Lmax was measured by an enzymatic method., Results: Six weeks of IMT significantly (P < 0.05) increased resting PImax. Moreover, inspiratory muscle training increased PImax following the VO2max test in the T group. In contrast, no changes in PImax were observed in the C group during the 6-week period. No significant differences were observed between pre- and post-test values in VO2max, dyspnea sensation, Lmax, and 2000 m race time in both groups., Conclusion: In conclusion, six weeks of IMT increases inspiratory muscle strength by approximately 28% in highly trained rowers. However, this increase in inspiratory muscle strength does not appear to improve VO2max, dyspnea sensation during exercise, or rowing performance in well-trained rowers.

Aim: The purpose of this study was to evaluate the seasonal variation in the cardiorespiratory fitness of soccer players according to positional role in the team., Methods: Thirty-two male soccer players U-19 years old were studied, consisting of 10 central defenders (18.2+/-0.9 years and 8.5+/-1.6 years of training (Group A), 12 midfielders (18+/-1 years and 8.1+/-1.4 years of training (Group B) and 10 attackers (18.2+/-0.9 years and 8.4+/-1.5 years of training (Group C). All subjects underwent anthropometric measurements and maximal exercise tests on a treadmill four times during their annual training cycle and maximal blood lactate accumulation analysis in order to verify that maximal exertion was reached. The measurements took place in the beginning and at the end of the preparation period, in the middle as well as at the end of the competitive season., Results: Group A showed increased VO2(max) (mL.kg(-1.)min(-1)) by 19.3% in the 2nd measurement, by 22.9% in the 3rd and by 17.6% in the 4th compared to the beginning, respectively (P

Background: This study examined the influence of knee angle on the cardiorespiratory system loading during submaximal and maximal stationary cycle ergometry., Methods: Experimental design and participants: eighteen untrained women (age: 21+/-1.88 years, weight: 57+/-5.75 kg, height: 165+/-5.03 cm, values are mean+/-SD) volunteered as subjects and underwent two-cycle ergometer incremental (Jaeger ER900) tests: 1) straight knee (180 degrees), 2) bent knee (140 degrees)., Measures: oxygen uptake (VO2), ventilation (VE) and respiratory exchange ratio (RER) were measured continuously during each test using an open circuit spirometry and blood lactate concentration was determined by means of an enzymatic method., Results: Comparing cycling with "straight knee" to cycling with "bent knee" at 50 W, heart rate (HR), V(E) and VO2 were significantly higher (10.6%, 12.5%, 17.8%). At 100 W, blood lactate was significantly lower (10.8%) while VO2 and RER was higher (5.5%, 7.1%). During maximal exercise, the total exercise time was significantly longer (11.2%) and VE, VO2 and HR were significantly higher during cycling with "straight knee" compared to cycling with "bent knee". No significant difference in peak lactate was evident between the two sitting positions., Conclusions: The results of this study indicate that cycling with bent knee requires lower oxygen uptake while pedaling with straight knee is the only way to reach VO2max during cycle testing, since the cardiorespiratory system is fully taxed.

The aim of this study was to examine the effect on heart rate, blood pressure and RPE on a bicycle ergometer performed with three different ways, i.e. with the anterior part of the foot, the posterior part of the foot and at saddle height with a knee angle of 120 degrees-125 degrees of submaximal and maximal work load. Untrained female (age X = 22 +/- 2.10 years, weight X = 56 +/- 5.4 kg, height X = 162 +/- 5.25 cm) volunteered as subjects. Heart rate and RPE at work load of 100 Watts were significantly lower in cycling with anterior part of the foot than with posterior part of the foot, while RPE in cycling with the posterior part of the foot was significantly lower in comparison to cycling with a knee angle of 120 degrees-125 degrees. Thirty three subjects were able to complete cycling on the load of 125 W with the anterior part of the foot; 28 with the posterior part of the foot and 22 with a knee angle of 120 degrees-125 degrees. It was concluded that cycling, (a) with the anterior part of the foot and the knee almost fully extended, is perceived easier and is more effective; (b) with the posterior part of the foot is tiring and ineffective and (c) with a low height of the saddle affects muscular work negatively.