Jumping Ability, Reactive Strength and Anthropometric Characteristics of Elite Junior Women Volleyball Players

Body size and dimensions, in conjunction with jumping ability, may constitute critical components for successful performance in Volleyball. The purpose of this study was: to measure a number of anthropome- tric characteristics and vertical jump performance of elite youth women volleyball players, from the national teams of the Balkan countries, and make comparisons based on nationality and players positions. The sam- ple consisted of eighty six athletes (age: 15.5–18.5 years) from Greece (GR, n=21), Bulgaria (BU, n=20), Serbia (SER, n=11), Moldavia (MOL, n= 9), Turkey (TUR, n=12) and Romania (RO, n=13), distributed also as setters (n=14), outside hitters (n=31), universals (n=12), middle blockers (n=22) and liberos (n=7). The subjects were measured for body height, body mass, body mass index (BMI) and body fat percentage and performed four types of vertical jump; a squat jump initiated from a knee flexion of 90o, a counter-movement jump, a coun- ter-movement jump with arm swing and a drop jump from a dropping height of 40 cm from which reactive strength was also calculated. According to the results, GR and RO had higher body fat percentage than MOL and BU (p<.05). Middle blockers were taller than the setters, the outside hitters and the liberos (p<.01). Uni- versals were taller than the setters and the liberos (p<.01) and the outside hitters than the liberos (p<.01). No differences were observed in BMI between the players and the teams (p>.05), though middle blockers had higher body mass than the setters, the outside hitters and the liberos (p<.05). In squat jump, counter move- ment jump and drop jump TUR had higher values than GR and BU (p<.05). In counter-movement jump with arm swing, TUR had also higher values than GR, BU and MOL (p<.05). Furthermore, TUR and SER had higher reactive strength values than GR and BU (p<.05) and TUR had also higher values than RO (p<.05). The evaluation of the physical characteristics and capacities provide the coaches useful information about the selection and development of young athletes as well as the effectiveness of the training programs

Short-term effects of selected exercise and load in contrast training on vertical jump performance

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 ⫾ SD age, 23 ⫾ 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% pro- tocol 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 preex- ercise 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

Effects of resistance training on the physical capacities of adolescent soccer players

This study examined the effects of a progressive resistance training program in ad- dition to soccer training on the physical capacities of male ado- lescents. Eighteen soccer players (age: 12–15 years) were sepa- rated 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 ⫻ 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 ⫻ 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

Effects of warm-up on vertical jump performance and muscle electrical activity using half-squats at low and moderate intensity

The purpose of this study was to determine the effects of a specific warm-up using half-squats at low and moderate intensity on vertical jump performance and electromyographic activity of the thigh muscles. The subjects were 26 men who were divided into a low intensity group (LIG; n = 13) and a moderate intensity group (MIG; n = 13). The LIG performed a specific warm-up protocol that included the explosive execution of half-squats with loads 25 and 35% of the one repetition maximum (1RM) and the MIG with loads 45 and 65% of the 1RM. The two groups performed a countermovement jump (CMJ) before and three minutes after the specific warm-up protocols. During the concentric phase of the CMJ a linear encoder connected to an A/D converter interfaced to a PC with a software for data acquisition and analysis allowed the calculation of average mechanical power. The electromyographic (EMG) activity of the vastus lateralis (VL), vastus medialis (VM) and rectus femoris (RF) were recorded during the concentric phase of the jumps. The average quadriceps (Qc) activity (mean value of the VL, VM and RF) was also calculated. A two way ANOVA (proto-cols X time) with repeated measures on the second factor was used to analyze the data. Following the specific warm-up procedure both groups improved (p ≤ 0.05) CMJ performance and mechanical power by 3.5% and 6.3%, respectively, with no differences observed between the two groups. EMG activity of the Qc and VL increased (p ≤ 0.05) for both groups by 5.9% and 8.5%, respectively. It is concluded that the use of a specific warm-up that includes half-squats, performed explosively with low to moderate intensity, improves CMJ performance. This may be due to increased muscle activation as evaluated by the surface EMG. {\textcopyright} Journal of Sports Science and Medicine

The differential hormonal milieu of morning versus evening, may have an impact on muscle hypertrophic potential

Substantial gains in muscle strength and hypertrophy are clearly associated with the routine performance of resistance training. What is less evident is the optimal timing of the resistance training stimulus to elicit these significant functional and structural skeletal muscle changes. Therefore, this investigation determined the impact of a single bout of resistance training performed either in the morning or evening upon acute anabolic signalling (insulin-like growth factor-binding protein-3 (IGFBP-3), myogenic index and differentiation) and catabolic processes (cortisol). Twenty-four male participants (age 21.4±1.9yrs, mass 83.7±13.7kg) with no sustained resistance training experience were allocated to a resistance exercise group (REP). Sixteen of the 24 participants were randomly selected to perform an additional non-exercising control group (CP) protocol. REP performed two bouts of resistance exercise (80% 1RM) in the morning (AM: 0800 hrs) and evening (PM: 1800 hrs), with the sessions separated by a minimum of 72 hours. Venous blood was collected immediately prior to, and 5 min after, each resistance exercise and control sessions. Serum cortisol and IGFBP-3 levels, myogenic index, myotube width, were determined at each sampling period. All data are reported as mean ± SEM, statistical significance was set at P≤0.05. As expected a significant reduction in evening cortisol concentration was observed at pre (AM: 98.4±10.5, PM: 49.8±4.4 ng/ml, P0.05). Timing of resistance training regimen in the evening appears to augment some markers of hypertrophic potential, with elevated IGFBP-3, suppressed cortisol and a superior cellular environment. Further investigation, to further elucidate the time course of peak anabolic signalling in morning vs evening training conditions, are timely

Effect of different intensities of active recovery on sprint swimming performance

Active recovery reduces blood lactate concentration faster than passive recovery and, when the proper intensity is applied, a positive effect on performance is expected. The purpose of the study was to investigate the effect of different intensities of active recovery on performance during repeated sprint swimming. Nine male well-trained swimmers performed 8 repetitions of 25 m sprints (8 ± 25 m) interspersed with 45 s intervals, followed by a 50 m sprint test 6 min later. During the 45 s and 6 min interval periods, swimmers either rested passively (PAS) or swam at an intensity corresponding to 50% (ACT60) and 60% (ACT60) of their individual 100 m velocity. Blood lactate was higher during PAS compared with ACT50 and ACT60 trials (p < 0.05), whereas plasma ammonia and glycerol concentration were not different between trials (p > 0.05). Mean performance time for the 8 × 25 m sprints was better in the PAS compared with the ACT50 and ACT60 trials (PAS: 13.10 ± 0.07 vs. ACT50: 13.43 ± 0.10 and ACT60: 13.47 ± 0.10s, p < 0.05). The first 25 m sprint was not different across trials (p > 0.05), but performance decreased after sprint 2 during active recovery trials (ACT50 and ACT60) compared with the passive recovery (PAS) trial (p < 0.05). Performance time for the 50 m sprint performed 6 min after the 8 ± 25 m sprints was no different between trials (p > 0.05). These results indicate that active recovery at intensities corresponding to 50% and 60% of the 100 m velocity during repeated swimming sprints decreases performance. Active recovery reduces blood lactate concentration, but does not affect performance on a 50 m sprint when 6 min recovery is provided. Passive recovery is advised during short-interval repeated sprint training in well-trained swimmers. © 2006 NRC Canada