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Evaluation of Physical, Performance and Emission Characteristics of Green Sand
Abstract
For many years, researchers in the foundry industry and universities have been developing testing protocols to evaluate the physical, performance and emission characteristics of prepared green sand during pouring, cooling and shakeout. This paper will review the testing protocol and methods utilized in the collection and evaluation of these characteristics that is the result of the entire metal casting process. An important criterion also is the quality of the green sand mold and casting produced (defect free) when the emission characteristics are reduced. This paper will also include the laser imaging evaluation of the castings that is the result of the green sand foundry emissions.
... The vast majority of jumping in volleyball occurs in the frontcourt, consisting of attacking spike jumps (SPJ) and defensive block jumps (BLJ), with setters also performing jump sets (JS). However, backcourt offensive attacks (i.e., SPJ) are a significant component of play, particularly with men (Polglaze and Dawson 1992;Viitasalo 1991;Viitasalo et al. 1987). Furthermore, defensive diving efforts are a physiological stress that must be considered . ...
... Indeed, testing measures such as spike jump (with three-or four-step approach), block jump (countermovement jump with two-arm reach), and countermovement vertical jump (countermovement jump with one-arm reach) are typical of most programs (Gladden and Colacino 1978;Heimer et al. 1988;Marques et al. 2008;Newton et al. 1999;Smith et al. 1987;Spence et al. 1980). The use of these measures is supported by their ability to discriminate between higher and lower performers within the sport (Heimer et al. 1988;Smith et al. 1992;Spence et al. 1980;Viitasalo 1991). Considering the tactical nature and importance of jumping activities and the frequency with which they occur in a typical match, countermovement jump ability (i.e., jump and reach height) and approach jump ability (i.e., spike jump height) are considered critical performance indicators for volleyball and are a feature of the physiological profile of a volleyball player (Sheppard et al. 2008b(Sheppard et al. , 2009a(Sheppard et al. , 2009bSpence et al. 1980;Viitasalo 1991). ...
... The use of these measures is supported by their ability to discriminate between higher and lower performers within the sport (Heimer et al. 1988;Smith et al. 1992;Spence et al. 1980;Viitasalo 1991). Considering the tactical nature and importance of jumping activities and the frequency with which they occur in a typical match, countermovement jump ability (i.e., jump and reach height) and approach jump ability (i.e., spike jump height) are considered critical performance indicators for volleyball and are a feature of the physiological profile of a volleyball player (Sheppard et al. 2008b(Sheppard et al. , 2009a(Sheppard et al. , 2009bSpence et al. 1980;Viitasalo 1991). However, we have observed large variability in the performance of the block jump, likely due to athletes' inability to complete the two-arm reach with their hands at the same height consistently. ...
... V olleyball is a sport comprised of many explosive efforts, characterized by multiple short bouts of high-intensity exercise, interspersed with brief rest periods (11,26). The high-intensity exercise and short recovery periods, with a total match duration of 60 to 90 minutes, would suggest that volleyball players require well-developed creatine phosphate and glycolytic energy systems as well as reasonably well-developed oxidative capabilities (4,22,23,25,26). ...
... The volleyball time-motion analysis (TMA) studies that have been published have generally been performed on competition before several rule changes (1999), which include player substitution rules and a major change from service scoring to rally-point scoring (4,11,25). Furthermore, anecdotally, many coaches believe that the player substitution rule changes (particularly the addition of the defensive specialist ''libero'' position) and evolving tactical play strategies have led to an increase in the specialization of player positions, which logically would impact upon the specialized nature of the physiologic profiles among these player positions. ...
... V olleyball is a sport comprised of many explosive efforts, characterized by multiple short bouts of high-intensity exercise, interspersed with brief rest periods (11,26). The high-intensity exercise and short recovery periods, with a total match duration of 60 to 90 minutes, would suggest that volleyball players require well-developed creatine phosphate and glycolytic energy systems as well as reasonably well-developed oxidative capabilities (4,22,23,25,26). ...
... The volleyball time-motion analysis (TMA) studies that have been published have generally been performed on competition before several rule changes (1999), which include player substitution rules and a major change from service scoring to rally-point scoring (4,11,25). Furthermore, anecdotally, many coaches believe that the player substitution rule changes (particularly the addition of the defensive specialist ''libero'' position) and evolving tactical play strategies have led to an increase in the specialization of player positions, which logically would impact upon the specialized nature of the physiologic profiles among these player positions. ...
The purpose of this study was to investigate the physiologic demands, physiologic characteristics, and jumping ability of different playing positions in elite male volleyball players. The first investigation involved an analysis of 16 international men's volleyball matches. The second investigation involved an analysis of the anthropometric and jump performance characteristics of 142 Development National Team (DNT) and Senior National Team (SNT) international volleyball players. Mean (+/-SD) frequency of block jumps for Middles (11.00 +/- 3.14) was significantly greater than for Setters (6.25 +/- 2.87, p < 0.001) and Outsides (6.50 +/- 3.16, p < 0.001). Attack jumps were performed more frequently by Middles (7.75 +/- 1.88), and this was found to be significantly more than for Setters (0.38 +/- 1.06, p < 0.001) and Outsides (5.75 +/- 3.25, p < 0.01). Middles were taller than Outsides and Setters (p < 0.001). Consequently, Middles had a significantly higher reach and greater body mass than Outsides (p < 0.001, p < 0.003) and Setters (p < 0.001, p < 0.001). Both Middles and Outsides had superior countermovement vertical jump (CMVJ) and spike jump (SPJ) scores compared with Setters (p < 0.001). Position-specific comparisons between DNT players and SNT players demonstrated that the SNT players were superior in relative CMVJ and SPJ scores (p < 0.05), with a large magnitude of effect (d > 0.99). The results of this study highlight the large jumping and landing demands placed on the taller and heavier players in the middle position. In addition to establishing the magnitude of difference in jumping ability between junior and senior national team players, the results also provide a comprehensive data set that may assist with talent identification and talent development for aspiring male volleyball players.
... The characteristics of volleyball include frequently repeated high-intensity exercise and rest for a short time 16,17) . Players perform high-intensity intermittent actions such as passing a ball, spiking, blocking and receiving 18) . ...
In various sports, high-intensity training reduces the oral immune function of the player. The effect of volleyball training camp on salivary immune function is unclear. This study aimed to investigate the effect of pre-season training on salivary immune function in elite collegiate volleyball players. Twenty-one elite collegiate volleyball players (mean age: 19.6 ± 1.1 years, mean height: 185.2 ± 7.8 cm) participated in this observational study. Saliva samples were taken on Day-1 (First day) and Day-11 (Final day) during pre-season training camp. Fatigue was measured using a VAS (visual analog scale) every day during the training camp period. Oral immune function was assessed in terms of secretory immunoglobulin A (s-SIgA) secretion rate and nitric oxide (s-NO) secretion rate. The s-NO secretion rate showed no significant change from Day-1 (0.69 ± 0.49 µmol/min) to Day-11 (0.56 ± 0.33 µmol/min). However, the s-SIgA secretion rate on Day-11 (28 ± 16 µg/min) was significantly lower (P < 0.05) than that on Day-1 (35 ± 18 µg/min). Changes in fatigue scale scores positively correlated with changes in s-NO secretion rate (rs = .591, P < 0.01), but not with changes in s-SIgA secretion rate (rs = .411, P = 0.06). In this study, the concentration of s-NO stored frozen was determined, but the effect of the storage method on s-NO should be investigated in future studies. In conclusion, pre-season volleyball training camp may affect oral immune function as in other sports.
... el voleibol es un deporte caracterizado por acciones de juego de corta duración y gran intensidad (cada punto dura 4-8 segundos), alternadas por cortos períodos de descanso (12 a 15 segundos) entre punto y punto (1, 2, 3, 4) y con recuperaciones más prolongadas entre cada set. el tiempo total de juego de un partido oscila entre 1 y 2 horas en función del número de sets que se disputen. ...
Objetivo: El propósito del presente estudio fue analizar la relación de la resistencia de base general con la resistencia de base especial en el voleibol profesional, a lo largo de una temporada. Nuestra hipótesis es que se puede lograr un incremento de la resistencia de base especial, sin una mejora concomitante de la resistencia de base general. Métodos: Se realizó un estudio longitudinal de 11 jugadoras, pertenecientes a la plantilla de un equipo profesional de voleibol, durante la temporada 2006-2007. Para al análisis de las resistencias de base general y especial se valoró el VO2máx, Umbral Anaeróbico mediante ergometría en tapiz y la altura media obtenida en el Test de saltos múltiples (RJ – 15’’), en diferentes momentos de la temporada. Resultados: La resistencia de base general se comportó de forma estable a lo largo de la temporada, mientras que la resistencia de base especial tuvo ganancias y pérdidas, estadísticamente significativas. Conclusión: Se concluye que, para aumentar la resistencia de base especial no es necesaria una mejora simultánea de la resistencia de base general.
... V olleyball is characterized by short and frequent explosive activities such as jumping, diving, and ball play (11,17). Jumping activities can include both horizontal approach movements (spike jumps [SPJ]), as well as movements without an approach but generally involving a countermovement (jump setting, jousts, blocking) (11,16). In consideration of the importance of these jumping activities to the performance outcome in volleyball and the frequency that they occur in a typical match, both countermovement vertical jump ability (CMVJ) and SPJ are important performance indicators in volleyball (5,13,15). ...
The purpose of this investigation was to examine the strength, power, and anthropometric contributors to vertical jump performances that are considered specific to volleyball success, including countermovement vertical jump (CMVJ) and spike jump (SPJ), by examining changes across 12 months in elite volleyball players. Anthropometry (height, mass, summation Sigma 7 skinfolds), vertical jump ability (CMVJ, SPJ, and depth jumps from 35 cm), kinetic and kinematic data from an unloaded and loaded (body mass + 50%) jump squat were assessed before and after 12 months of training in 20 elite male volleyball players. To examine the association between the change in each of the strength, power, and anthropometric variables with the changes in CMVJ and SPJ, a correlation analysis of the percent change of each variable with the percent change in CMVJ and SPJ was performed. A significant correlation (r = 0.47; p = 0.04) was observed between changes in CMVJ and SPJ. Significant (p = 0.006-0.02) improvements in CMVJ were associated with increased peak force in the unloaded (r = 0.61) and loaded jump squat (r = 0.59) and greater relative power and peak velocity in the loaded jump squat (r = 0.49 and 0.51, respectively). The significant increase in CMVJ was strongly associated (r = 0.865; p < 0.001) with an improved depth-jump ability. Significant (p = 0.003-0.03) increases in SPJ were related to increases in relative power (r = 0.64), peak force (r = 0.46), and peak velocity (r = 0.49) in the loaded jump and improved depth-jumping ability (r = 0.591). This study demonstrates that, in an elite population of volleyball players, stretch-shortening cycle performance and the ability to tolerate high stretch loads, as in the depth jump, are critical to improving jumping performance.
Ένα σύνολο από 74 υγιείς Έλληνες αθλητές πετοσφαίρισης (ηλικίας 23,2 ± 3,4 ετών,
αναστήματος 193,3 ± 6,2 cm, σωματικής μάζας 88 ± 6,3 Kg) εθνικών ομάδων και ομάδων Α΄
Εθνικής Κατηγορίας εξετάσθηκαν για τη μέγιστη (Fmax) και εκρηκτική (Fexp) δύναμη των
κάτω άκρων (leg press, σε 90o
γωνία του γονάτου, σε ισομετρικές συνθήκες), για τη μέγιστη
ταχύτητα περιστροφής σε στατικό ποδήλατο χωρίς εξωτερική επιβάρυνση, ως έκφραση της
μέγιστης ταχύτητας συστολής των μυών των ποδιών (fcmax) και για την αλτική ικανότητα
(hsj, hcmj). Επίσης αξιολογήθηκαν στη μέγιστη ισοκινητική ροπή των εκτεινόντων (Q30 and
Q180) και των καμπτήρων (H30 and H180) του γονάτου, στις γωνιακές ταχύτητες των 30 και
180 o
/s, με τη χρήση του ισοκινητικού μηχανήματος Cybex 340. Υπολογίστηκε επίσης ο
λόγος καμπτήρων/εκτεινόντων (H/Q ratio). Η Fmax ήταν 2,98 ± 0,54 Σ.Β., η Fexp ήταν 1,93 ±
0,38 kp/ms, η fcmax 3,80 ± 0,25 c/s, το hsj 49,6 ± 4,4 cm και το hcmj 65,0 ± 7,0 cm. Τα
αποτελέσματα της μέγιστης ισοκινητικής ροπής ήταν για τους εκτείνοντες του γονάτου Q30 =
4,1 ± 0,5 Nm/kg και Q180 = 2,4 ± 0,3 Nm/kg και για τους καμπτήρες H30 = 2,2 ± 0,3 Nm/kg
και H180 = 1,5 ± 0,2 Nm/kg. Ο H/Q ratio ήταν 53,1 ± 5,1 και 62,7 ± 9,2 για τη γωνιακή
ταχύτητα 30 o
/s και 180 o
/s αντίστοιχα. Η ανάλυση συσχέτισης αποκάλυψε μέτριους
συντελεστές συσχέτισης (r = 0,49 – 0,56) μεταξύ των παραμέτρων της ισοκίνησης και των
δοκιμασιών ισχύος.
Η παρούσα μελέτη εμπλουτίζει τις βάσεις δεδομένων για τα δυναμικά χαρακτηριστικά των
κάτω άκρων κορυφαίων αθλητών πετοσφαίρισης.
Increasing lower body strength is often considered to be important for improving the sprinting speed of rugby players. This concept was examined in a group (n=40) of international rugby players in a two part study. The players were tested for body mass (BM), one repetition maximum power clean (PC) and front squat (FS), as well as triple broad jump (TBJ) and broad jump (BJ). In addition, speed over 40 m was tested, with timing gates recording the 0-10 m and 30-40 m sections in order to assess acceleration and maximal velocity. Two video cameras recorded the two splits for later analysis of sprinting kinematics. The players were divided into a fast group (n=20) and a slow group (n=20) for both acceleration and maximal velocity. In the second part of the study, a group (n=15) of players were tracked over a one year period to determine how changes in strength corresponded with changes in sprinting kinematics. The fast groups for both acceleration and maximal velocity showed greater levels of strength (d=0.5 - 1.8), lower ground contact times (d=0.8 - 2.1), and longer stride lengths (d=0.5 - 1.3). There was a moderate improvement over 1 year in PC/BM (0.08 kg/kg, P=0.008, d=0.6) and this had a strong relationship with the change in maximal velocity stride length (r=0.70). Acceleration stride length also had a large improvement over one year (0.09 cm, P=0.003, d=0.81). While increasing lower body strength is likely important for increasing sprinting speed of players with low training backgrounds, it may not have the same effect with highly trained players.
Background
Several examinations have demonstrated differences in anthropometry, jump performance, and strength variables between developmental and elite level volleyball players. However, within the elite level of play, the magnitude of change that can occur with training is unclear.
Objective
To examine the anthropometric, vertical jump, and strength quality changes over 2 years in a group of national team volleyball players.
Design
Longitudinal analysis with pre and post measurements spanning a 2 year time period.
Setting
A male national volleyball team, involving professional players free of injury.
Participants
15 national team volleyball players (22.0±3.1 years, 1.98±0.09 m, 90.8±9.9 kg) began and completed this study. Participants had all played international matches prior to the examination time period, and continued to do so during the international season, while also playing for their professional club, through the 2 year duration of the study.
Interventions
During professional seasons, match play volume varied depending on club, with training time typically involving four to seven court and two strength sessions per week. During international seasons, participants typically engaged in seven to nine court and two to four strength sessions per week, with match involvement ranging from 15 to 40 per season. Anthropometry (stature, mass, and Σ7 skin-folds, vertical jump measures (counter-movement vertical jump; depth-jump from 0.35 m DJ; spike-jump SPJ), speed-strength (body-weight jump squat, JSBW) and ballistic-strength (jump squat+50% body-weight, JS50) measures were tested prior to and at the conclusion of the investigation period.
Results
Significant (p<0.05) improvements were observed in Σ7 skin-folds, DJ, SPJ, and JS50 performance, with large magnitude changes (Cohen's d>0.70) in the Σ7 skin-folds reduction, and increased jump height for the JS50.
Conclusions
Large improvements in DJ, SPJ, and ballistic strength performance, as well as reductions in fat-mass, can be achieved in senior male national team volleyball players.
The purpose of this investigation was to examine the changes in performance indicators as they relate to strength and speed-strength development, over 2 years in a group of volleyball players who successfully transitioned from age group (U21) to senior national team in that time period. Sixteen male subjects (age: 18.5 ± 1.5 years, height: 2.00 ± 0.06 m, and weight: 88.4 ± 7.7 kg) participated in this 2-year longitudinal study. During the 24-month period of this investigation, all the subjects gained professional European contracts and also debuted with at least 1 senior national team match. These included, at a minimum, not only international friendly matches but also senior continental championships, World Championships, and the World Cup. Testing included 1 repetition maximum (1RM) and 3RM for the clean and squat, a maximum effort counter movement vertical jump (CMVJ), depth jump from a 0.35-m box (DJ), spike jump (with approach) (SPJ), and lower body speed-strength assessment with a body weight and body weight + 50% load. Large magnitude increases were observed for CMVJ, DJ, and SPJ over the 2-year period (d = 0.80, 0.82, and 0.94, respectively, p < 0.001). Unloaded (body weight) and loaded jump-squat performance also exhibited large improvements for all measured parameters, with very large increases in jump height in the unloaded (d = 1.21, p = 0.002) and loaded jump squat (d = 1.346, p < 0.001). Very large magnitude changes in 1RM Clean and 3RM Squat (d = 1.56 and 2.21, respectively, p < 0.001) were observed over the 2-year investigation period, and a large increase (d = 1.18, p < 0.001) in the lean mass ratio (mass/sum skinfolds). To progress from junior representation to senior national team, volleyball players must increase their CMVJ and SPJ. This is best accomplished through increasing lean mass, reducing fat mass, improving strength and speed strength, and developing high levels of stretch-load tolerance in stretch-shorten cycle activity.
Several investigations have demonstrated differences in anthropometry, jump performance, and strength variables between developmental and elite-level volleyball players. However, within the elite level of play, the magnitude of change that can occur with training is unclear. The purpose of this investigation was to examine the anthropometric, vertical jump, and strength quality changes over 2 years in a group of national team volleyball players. Fourteen national team volleyball players (age, 23.0 ± 4.1 years; height, 1.98 ± 0.07 m; weight, 91.7 ± 7.9 kg) began and completed this study. Participants had all played international matches (representing Australia) before the examination time period and continued to do so during the international season. Anthropometry (stature, mass, and sum of 7 skinfolds), vertical jump measures (countermovement vertical jump; depth jump from 0.35 m, DJ; spike jump, SPJ, all including arm swing), and lower-body power (jump squat at body mass, and jump squat + 50% body weight, JS50) measures were tested before and at the conclusion of the investigation period. Significant (p < 0.05) improvements were observed in sum of 7 skinfolds, DJ, SPJ, and JS50 performance, with large magnitude changes (d > 0.70) in the sum of 7 skinfolds reduction, SPJ, and leg extensor power. This study has demonstrated that elite male volleyball players can improve leanness and power, which contribute to improvements in vertical jump.
The purpose of this investigation was to examine the potential strength, power, and anthropometric contributors to vertical jump performances that are considered specific to volleyball success: the spike jump (SPJ) and counter-movement vertical jump (CMVJ). To assess the relationship among strength, power, and anthropometric variables with CMVJ and SPJ, a correlation and regression analysis was performed. In addition, a comparison of strength, power, and anthropometric differences between the seven best subjects and the seven worst athletes on the CMVJ test and SPJ test was performed. When expressed as body mass relative measures, moderate correlations (0.53-0.65; p < or = 0.01) were observed between the 1RM measures and both relative CMVJ and relative SPJ. Very strong correlations were observed between relative (absolute height-standing reach height) depth jump performance and relative SPJ (0.85; p < or = 0.01) and relative CMVJ (0.93; p </= 0.01). The single best regression model component for relative CMVJ was the relative depth jump performance, explaining 84% of performance. The single best predictor for relative SPJ was also the relative depth jump performance (72% of performance), with the three-component models of relative depth jump, relative CMVJ, spike jump contribution (percent difference between SPJ and CMVJ), and relative CMVJ, spike jump contribution, and peak force, accounting for 96% and 97%, respectively. The results of this study clearly demonstrate that in an elite population of volleyball players, stretch-shortening cycle performance and the ability to tolerate high stretch loads, as in the depth jump, is critical to performance in the jumps associated with volleyball performance.
Failure to formulate the correct quantity and type of Sea coal will result in unacceptable Iron Castings! Sea coal is one of the critically formulated ingredients in prepared green sand molding operations. A review of the role and benefits of using Sea coal in the production of iron castings produced in green sand will be reviewed in detail.
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