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The aim of the present study was to assess the level of self-perception, self-esteem, physical activity and sedentary behavior of primary school children between 10 and 12 years old in the city of Komotini (Rodopi East Greece, North), to investigate the correlation between the above parameters and to detect possible differentiation on each factor with regard to the age and gender of the children. The sample of the survey consisted of 153 students from five public primary schools. The students were divided according to their gender (boy-girl) and class grade. Data were obtained from the Self-Perception Profile for Children and the "Self-administered physical activity interview checklist". The analysis showed that self-perception, self-esteem and physical activity was on a satisfactory-high level. In addition, the sedentary behavior of participants was high. Physical activity had a positive effect on the self-concept/self-esteem. Girls were found to have a higher level of self-perception than boys in the behavior conduct scale, while boys generally showed higher global self -- worth compared to girls. Older students showed higher self-perception in scholastic and social competence, while they had a lower global self-worth. Moreover, it was noted that students whose parents had a high level of education had higher self-concept in scholastic competence.

AIM: The aim of this study was to investigate the infl uence of systematic training in physical growth and biological maturity in prepubertal males and estimate how this affects the physical growth and skeletal maturity. MATERIALS AND METHODS: 177 primary school students of the fifth and sixth grade, from schools in Alexandroupolis, participated voluntarily in our study. Questionnaires were used in order to measure physical activity levels. The subjects were subdivided into two groups; control group (prepubertal, whose physical activity was the physical education of their school and which had never participated in systematic training, n = 95) and experimental group (prepubertal, whose weekly physical activity included physical education in their schools and additionally 3-4 training units organized training in various sports clubs in the city, n = 82). The following parameters were recorded: biological age measured by determination of skeletal age; bone density measured by ultrasound methods; anthropometric and morphological features such as height, body composition, selected diameters, circumferences and skinfolds; motor ability features. RESULTS: The experimental group exhibited older biological age (p = 0.033), higher bone density (p < 0.001), lower BMI and body fat (p < 0.001), better anthropometric features and higher performance throughout all motor ability tests (p < 0.05), compared to the control group. CONCLUSION: The present study demonstrates that systematic physical activity has a positive effect on both the physical and biological maturity of pre-pubertal children. This effect is mainly expressed in bone strengthening as a result of the increased bone density and in improvement of the kinetic skills of pupils who participated in organized extracurricular sport-activities.

The purpose of this study was to examine (a) the mechanical power and the electromyographic (EMG) activity during a moderate load muscular endurance session and (b) the maximal mechanical power output and EMG activity using a light load and a heavy load afterward. Sixteen men (age: 20.7 [+ or -] 1.1 years) performed 4 sets of 20 repetitions with an initial load of 50% of 1 repetition maximum (1RM), and 2 minutes of rest, in the squat exercise. Furthermore, the subjects performed 4 repetitions with loads of 40 and 80% of 1RM before, immediately after, and 30 minutes after the end of the session. Average power and EMG activity from vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF) were recorded during the concentric phase of the lift. Average power did not change during the first 2 sets, while it decreased (p < 0.05) during the third and the fourth set. Average quadriceps (AQ), VM, VL, and RF activity increased (p < 0.05) until the 11th repetition, approximately, during each set while it increased gradually from set to set. Maximal power and AQ, VM, and VL activity with the loads of 40 and 80% of 1RM were decreased (p < 0.05) after the session. Blood lactate reached 10.2 [+ or -] 2.5 and 13.1 [+ or -] 4.1 mmol x [L.sup.-1] after the second and the fourth set, respectively. It appears that during a muscular endurance session with submaximal power output, mechanical performance may gradually decrease, probably due to metabolic fatigue, while muscle electrical activity may increase. Following this type of a session, maximal power output and muscle activation with a light and especially with a heavy load are reduced. KEY WORDS weight training, fatigue, lactate, muscle activity, performance

Myrkos, A, Smilios, I, Zafeiridis, A, Iliopoulos, S, Kokkinou, EM, Douda, H, and Tokmakidis, SP. Effects of work and recovery duration and their ratio on cardiorespiratory and metabolic responses during aerobic interval exercise. J Strength Cond Res 36(8): 2169–2175, 2022—This study examined the effect of work and recovery durations and of work-to-rest ratio (WRR) on total exercise time and oxygen consumption (V̇ o 2max), on exercise time above 80, 90, and 95% of V̇ o 2max and HRmax, and on blood lactate concentrations during aerobic interval exercise. Twelve men (22.1 ± 1 year) executed, until exhaustion, 4 interval protocols at an intensity corresponding to 100% of maximal aerobic velocity. Two protocols were performed with work bout duration of 120 seconds and recovery durations of 120 (WRR: 1:1) or 60 seconds (WRR: 2:1), and 2 protocols with work bout duration of 60 seconds and recovery durations of 60 (WRR: 1:1) or 30 seconds (WRR: 2:1). When compared at equal exercise time, total V̇ o 2 and exercise time at V̇ o 2 above 80, 90, and 95% of V̇ o 2max were longer (p < 0.05) in 120:120, 120:60 and 60:30 vs. the 60:60 protocol. When analyzed for total exercise time (until exhaustion), total V̇ o 2 was higher (p < 0.01) in the 60:60 compared with all other protocols, and in the 120:120 compared with 120:60. Exercise time >95% of V̇ o 2max and HRmax was higher (p < 0.05) in the 120:120 vs. the 60:60 protocol; there were no differences among protocols for exercise time >90% of V̇ o 2max and HRmax. Blood lactate was lower (p < 0.05) in the 60:60 compared with all other protocols and in the 60:30 vs. the 120:60. In conclusion, when interval exercise protocols are executed at similar effort (until exhaustion), work and recovery durations do not, in general, affect exercise time at high oxygen consumption and HR rates. However, as work duration decreases, a higher work-to-recovery ratio (e.g., 2:1) should be used to achieve and maintain high (>95% of maximum) cardiorespiratory stimulus. Longer work bouts and higher work-to-recovery ratio seem to activate anaerobic glycolysis to a greater extent, as suggested by greater blood lactate concentrations. [ABSTRACT FROM AUTHOR]

This study examined the effects of a progressive resistance training program in addition to soccer training on the physical capacities of male adolescents. Eighteen soccer players (age: 12-15 years) were separated in a soccer (SOC; n = 9) and a strength-soccer (STR; n = 9) training group and 8 subjects of similar age constituted a control group. All players followed a soccer training program 5 times a week for the development of technical and tactical skills. In addition, the STR group followed a strength training program twice a week for 16 weeks. The program included 10 exercises, and at each exercise, 2-3 sets of 8-15 repetitions with a load 55-80% of 1 repetition maximum (1RM). Maximum strength ([1RM] leg press, bench-press), jumping ability (squat jump [SJ], countermovement jump [CMJ], repeated jumps for 30 seconds) running speed (30 m, 10 x 5-m shuttle run), flexibility (seat and reach), and soccer technique were measured at the beginning, after 8 weeks, and at the end of the training period. After 16 weeks of training, 1RM leg press, 10 x 5-m shuttle run speed, and performance in soccer technique were higher (p < 0.05) for the STR and the SOC groups than for the control group. One repetition maximum bench press and leg press, SJ and CMJ height, and 30-m speed were higher (p < 0.05) for the STR group compared with SOC and control groups. The above data show that soccer training alone improves more than normal growth maximum strength of the lower limps and agility. The addition of resistance training, however, improves more maximal strength of the upper and the lower body, vertical jump height, and 30-m speed. Thus, the combination of soccer and resistance training could be used for an overall development of the physical capacities of young boys. KEY WORDS. agility, flexibility, growth, running speed, strength, vertical jump

Purpose: This study examined the acute effects of contrast loading on mechanical power output during benchpress throws in junior volleyball players. Method: Eleven males (age: 16.5 ± 0.5 years) performed a contrast loading and a control protocol. The contrast protocol included the execution of 3 bench-throws with a 30% load of 1RM, after 3 min a conditioning set of 5 bench-throws with a 60% load of 1RM and after 3 and 5 min two more sets of 3 bench-throws with a 30% load of 1RM. The control protocol included the execution of 3 sets of 3 bench-throws with a 30% load of 1RM at the same time points as in the contrast protocol without the execution of the conditioning set. Results: Mechanical power with a 30% load was higher (p < .05) 3 and 5 min following the conditioning set at the contrast protocol compared with the control protocol (8.7 ± 7.5 and 10.4 ± 3.4%, respectively). High correlations (p < .05) were obtained between participant's relative maximal strength (r = .87) and power (r = .82) and the increases in power output. Conclusion: Contrast loading increases upper body power output produced with a light load by junior athletes. The potential for increased upper body performance is more evident in stronger or more powerful individuals. [ABSTRACT FROM AUTHOR]

Resistance training can improve strength and functional performance, but there is little information about the effect of training intensity on functional performance in older adults. The purpose of this study was to determine the effect of 12 weeks of heavy (80% of 1 repetition maximum [1RM]) and moderate (60% of 1RM) resistance training on functional performance in healthy, inactive older adults, ages 60-74 years. Volunteer subjects were assigned randomly to a control group (CS, n = 10), heavy resistance training group (HRT, n = 11), or moderate resistance training group (MRT, n = 12) and participated in 12 weeks of strength training, 3 times per week. Performance measurements included 1RM lower-body strength, chair-rising time, walking velocity, stair-climbing time, and flexibility. Significant differences between HRT and MRT were found for 1RM strength of the lower limbs after the training period. Functional performance improved similarly for both HRT and MRT after the training period. Functional performance can be improved significantly with either heavy or moderate resistance training, without significant differences in the effectiveness of the 2 training protocols. Key Words. intensity, muscle strength, physical function, aging

The aim of the present study was to evaluate the anaerobic power of elite male volleyball players, using the Wingate Anaerobic Test to examine the relationship between anaerobic power and jumping performance. Athletes (n = 56) and Nonathletes (n = 53) were divided into three age groups: Adults (18-25 yr.), Juniors (15-16 yr.), and Youth (10-11 yr.). Measurements of height, body mass, vertical jump and Wingate scores indicated higher values for athletes. The specific training effects of anaerobic power were more pronounced at the age of 10-11 years than for Nonathletes. A significant correlation coefficient between peak power and vertical jump was found for Athletes (r = .86) and for the total group (r = .82). These results indicated that vertical jump may predict the maximal anaerobic power and could be used by coaches as a practical and easy-to-apply field screening test for evaluation in volley ball training.

Smilios, I., T. Pilianidis, K. Sotiropoulos, M. Antonakis, and S.P. Tokmakidis. Short-term effects of selected exercise and load in contrast training on vertical jump performance. J. Strength Cond. Res. 19(1):135-139. 2005.--The present study examined the short-term effects of loaded half squats (HSs) and loaded jump squats (JSs) with low and moderate loads on the squat jump (SJ) and the countermovement jump (CMJ) performance using a contrast training approach. Ten men (mean [+ or -] SD age, 23 [+ or -] 1.8 years) performed the HS and JS exercises twice with loads of 30% of 1 repetition maximum (1RM) (HS30% and JS30%, respectively) and 60% of 1RM (HS60% and JS60%, respectively). On each occasion, 3 sets of 5 repetitions with 3 minutes of rest were performed as fast as possible. Vertical jump performance was measured before exercise, 1 minute after each set, and at the fifth and 10th minutes of recovery. The CMJ increased significantly after the first and second set (3.9%; p < 0.05) compared with preexercise values following the JS30% protocol and 3.3% after the second and third sets of the JS60% protocol. Following the HS60% protocol, CMJ increased after the first and the second sets (3.6%; p < 0.05) compared with preexercise values, whereas SQ increased only after the first set (4.9%; p < 0.05) in this condition. These data show that contrast loading with the use of low and moderate loads can cause a short-term increase in CMJ performance. The applied loads do not seem to present different short-term effects after loaded JSs. When the classic form of dynamic HS exercise is performed, however, at least a moderate load (60% of 1RM) needs to be applied. KEY WORDS. jump squat, countermovement jump, squat jump, ballistic exercise, contrast training

The purpose of this study was to examine the effects of ibuprofen on delayed onset muscle soreness (DOMS), indirect markers of muscle damage and muscular performance. Nineteen subjects (their mean [+ or -] SD] age, height, and weight was 24.6 [+ or -] 3.9 years, 176.2 [+ or -] 11.1 cm, 77.3 [+ or -] 18.7 kg) performed the eccentric leg curl exercise to induce muscle soreness in the hamstrings. Nine subjects took an ibuprofen pill of 400 mg every 8 hours within a period of 48 hours, whereas 10 subjects received a placebo randomly (double blind). White blood cells (WBCs) and creatine kinase (CK) were measured at pre-exercise, 4-6, 24, and 48 hours after exercise and maximal strength (1 repetition maximum). Vertical jump performance and knee flexion range of motion (ROM) were measured at pre-exercise, 24 and 48 hours after exercise. Muscle soreness increased (p < 0.05) in both groups after 24 and 48 hours, although the ibuprofen group yielded a significantly lower value (p < 0.05) after 24 hours. The WBC levels were significantly (p < 0.05) increased 4-6 hours postexercise in both groups with no significant difference (p > 0.05) between the 2 groups. The CK values increased (p < 0.05) in the placebo group at 24 and 48 hours postexercise, whereas no significant differences (p > 0.05) were observed in the ibuprofen group. The CK values of the ibuprofen group were lower (p < 0.05) after 48 hours compared with the placebo group. Maximal strength, vertical jump performance, and knee ROM decreased significantly (p < 0.05) after exercise and at 24 and 48 hours postexercise in both the placebo and the ibuprofen groups with no differences being observed (p > 0.05) between the 2 groups. The results of this study reveal that intake of ibuprofen can decrease muscle soreness induced after eccentric exercise but cannot assist in restoring muscle function. Key Words: anti-inflammatory drugs, squat jump, counter movement jump, maximal concentric strength

The purpose of this study was to examine the test-retest reliability of the Eurofit motor fitness tests performed by university students. A total of 98 undergraduate students who were enrolled in physical education departments in Greece participated (29 men aged 19.5 [+ or -] 2.7 hr. and 66 women aged 19.4 [+ or -] 2.7 yr.). All Eurofit motor fitness tests and anthropometric measurements were obtained twice with one week between the two measurements. Intraclass correlation coefficient indicated satisfactory coefficients above .70 for most tests. The only exception was the plate-tapping test, which yielded a low value (R = .57). Further, the majority of the Eurofit test battery fitted well within the 95% confidence interval, and only three Eurofit motor fitness test items (flamingo balance, plate tapping, and sit-ups) presented a confidence limit below the value of .70. These findings indicated that the Eurofit test battery yielded reliable data for undergraduate students. However, modifications should be considered to improve the reliability of certain test items, for application to undergraduates.

This five-year follow-up nonrandomized controlled study evaluated community-based training and detraining on body composition and functional ability in older women. Forty-two volunteers (64.3 ± 5.1 years) were divided into four groups: aerobic training, strength training, combined aerobic and strength, and control. Body composition and physical fitness were measured at baseline, after nine months of training and after three months of detraining every year. After five years of training, body fat decreased, and fat free mass, strength, and chair test performance increased (p < .05) in all training groups. Training-induced favorable adaptations were reversed during detraining but, eventually, training groups presented better values than the control group even after detraining. Thus, nine months of annual training, during a five-year period, induced favorable adaptations on body composition, muscular strength, and functional ability in older women. Three months of detraining, however, changed the favorable adaptations and underlined the need for uninterrupted exercise throughout life. [ABSTRACT FROM AUTHOR]

Purpose: This study examined the effect of rest interval after the execution of a jump-squat set with varied external mechanical-power outputs on repeated-jump (RJ) height, mechanical power, and electromyographic (EMG) activity. Methods: Twelve male volleyball players executed 6 RJs before and 1, 3, 5, 7, and 10 min after the execution of 6 repetitions of jump squats with a load: maximized mechanical-power output (Pmax), 70% of Pmax, 130% of Pmax, and control, without extra load. Results: RJ height did not change (P = .44) after the jump squats, mechanical power was higher (P = .02) 5 min after the 130%Pmax protocol, and EMG activity was higher (P = .001) after all exercise protocols compared with control. Irrespective of the time point, however, when the highest RJ set for each individual was analyzed, height, mechanical power, and EMG activity were higher (P = .001-.04) after all loading protocols compared with control, with no differences observed (P = .53-.72) among loads. Conclusions: Rest duration for a contrast-training session should be individually determined regardless of the load and mechanical-power output used to activate the neuromuscular system. The load that maximizes external mechanical-power output compared with a heavier or a lighter load, using the jump-squat exercise, is not more effective for increasing jumping performance afterward. [ABSTRACT FROM AUTHOR]

Purpose: To examine the effects of active and passive recovery of various durations after a 100-m swimming test performed at maximal effort. Methods: Eleven competitive swimmers (5 males, 6 females, age: 17.3 ± 0.6 y) completed two 100-m tests with a 15-min interval at a maximum swimming effort under three experimental conditions. The recovery between tests was 15 min passive (PAS), 5 min active, and 10 min passive (5ACT) or 10 min active and 5 min passive (10ACT). Self-selected active recovery started immediately after the first test, corresponding to 60 ± 5% of the 100-m time. Blood samples were taken at rest, 5, 10, and 15 min after the first as well as 5 min after the second 100-m test for blood lactate determination. Heart rate was also recorded during the corresponding periods. Results: Performance time of the first 100 m was not different between conditions (P > .05). The second 100-m test after the 5ACT (64.49 ± 3.85 s) condition was faster than 10ACT (65.49 ± 4.63 s) and PAS (65.89 ± 4.55 s) conditions (P < .05). Blood lactate during the 15-min recovery period between the 100-m efforts was lower in both active recovery conditions compared with passive recovery (P < .05). Heart rate was higher during the 5ACT and 10ACT conditions compared with PAS during the 15-min recovery period (P < .05). Conclusion: Five minutes of active recovery during a 15-min interval period is adequate to facilitate blood lactate removal and enhance performance in swimmers. Passive recovery and/or 10 min of active recovery is not recommended. [ABSTRACT FROM AUTHOR]

Purpose: To identify the physiological and anthropometric predictors of rhythmic gymnastics performance, which was defined from the total ranking score of each athlete in a national competition. Methods: Thirty-four rhythmic gymnasts were divided into 2 groups, elite (n = 15) and nonelite (n = 19), and they underwent a battery of anthropometric, physical fitness, and physiological measurements. The principal-components analysis extracted 6 components: anthropometric, flexibility, explosive strength, aerobic capacity, body dimensions, and anaerobic metabolism. These were used in a simultaneous multiple-regression procedure to determine which best explain the variance in rhythmic gymnastics performance. Results: Based on the principal-component analysis, the anthropometric component explained 45% of the total variance, flexibility 12.1%, explosive strength 9.2%, aerobic capacity 7.4%, body dimensions 6.8%, and anaerobic metabolism 4.6%. Components of anthropometric (r = .50) and aerobic capacity (r = .49) were significantly correlated with performance (P < .01). When the multipleregression model-y = 10.708 + (0.0005121 × VO2max) + (0.157 × arm span) + (0.814 × midthigh circumference) - (0.293 × body mass)-was applied to elite gymnasts, 92.5% of the variation was explained by VO2max (58.9%), arm span (12%), midthigh circumference (13.1%), and body mass (8.5%). Conclusion: Selected anthropometric characteristics, aerobic power, flexibility, and explosive strength are important determinants of successful performance. These findings might have practical implications for both training and talent identification in rhythmic gymnastics. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the acute changes in leukocyte number and cortisol after a single bout of soccer training. Methods: Ten elite female national-team soccer players and 8 nonathletes participated in the study. The duration of the exercise was 2 h, and it was performed at an intensity of 75% of maximal heart rate (HRmax). Blood samples were taken before, immediately after, and 4 h after a soccer training session to determine total white blood cells; the subsets of neutrophils, lymphocytes, monocytes, eosinophils, and basophils; and cortisol. At the same time, blood samples were obtained from nonathletes who refrained from exercise. Results: Data analysis indicated a significant increase in total white blood cells in the athletes postexercise (P < .001). The leukocytosis was still evident after 4 h of recovery (78% higher than the preexercise values), and there was a significant difference between athletes and nonathletes (P < .001). This leukocytosis was primarily caused by neutrophilia—there were no significant differences in lymphocytes after the end of exercise or between the 2 groups (P > 0.05). In addition, there was a statistically significant difference in cortisol concentration between athletes and nonathletes after the exercise (P < .001). Conclusion: These findings revealed that the single bout of soccer training at an intensity of 75% of HRmax induced leukocytosis without affecting the lymphocyte count in elite female athletes and probably the effectiveness of cellular components of adaptive immunity. Coaches should provide adequate time (>4 h) until the next exercise session. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effects of a 12-week resistance-training program on muscle strength and mass in older adults. Thirty-three inactive participants (60-74 years old) were assigned to 1 of 3 groups: high-resistance training (HT), moderate-resistance training (MT), and control. After the training period, both HT and MT significantly increased 1-RM body strength, the peak torque of knee extensors and flexors, and the midthigh cross-sectional area of the total muscle. In addition, both HT and MT significantly decreased the abdominal circumference. HT was more effective in increasing 1-RM strength, muscle mass, and peak knee-flexor torque than was MT. These data suggest that muscle strength and mass can be improved in the elderly with both high- and moderate-intensity resistance training, but high-resistance training can lead to greater strength gains and hypertrophy than can moderate-resistance training. [ABSTRACT FROM AUTHOR]