Is it Possible to Estimate Match Result in Volleyball: A new Prediction Model

This study investigates the power of variables in a logistic regression model (the efficacy model or (EM)) to explain the match results in the Turkish Men’s Volleyball League (TMVL) and the Turkish Women’s Volleyball League (TWVL) in terms of the players’ positions. The dependent variable was the match result, and the power of the variables libero player efficiency (LPE), setter efficiency (SE), middle blocker efficiency (MBE), outside hitter efficiency (OHE) and universal player efficiency (UPE) were separately investigated for both genders. The EM accurately classified 83.45% of the games won and lost in the TWVL. The sensitivity (proportion of won games classified as won) and specificity (proportion of lost games classified as lost) was 85.03 and 81.88%, respectively. In the TMVL analysis, the classification accuracy, sensitivity and specificity were 78.23, 78.77 and 77.70%, respectively. Moreover, for both genders, the match results were chiefly explained by the SE, MBE, OHE and UPE. The LPE variable could not predict the results in the TWVL

The Effect of Relative Age on Some Performance Characteristics in Young Volleyball Players

It has been evaluated in the literature that different maturation levels exist in the same chronological age and this may be an advantage for athletic performance. The aim of this study was to examine the performance characteristics of young male and female volleyball players in the same chronological age according to their relative age.A total of 536 athletes who were 14 years old and similar training age, 238 male and 298 female subjects participated in this study. Relative age was determined by quitting the quartile of the year starting from January. Explosive strength (counter movement and squat jumps), anaerobic strength and capacity (Wingate test), aerobic capacity (20m shuttle run) and speed (5m and 10m sprint) were measured. 2x4 ANOVA was used to determine the differences between gender and relative age groups, and Bonferroni test was used to determine the differences between the quarters of the year. The significance level of all statistical procedures was accepted as 0.05.The distribution of volleyball players in the quarters was 47.9%, 27.7%, 17.6%, 6.7% for males, 39.9%, 29.5%, 17.4% and 13.1% for females respectively. The differences between the genders in all variables were statistically significant (p0.05).As a result of this study it was found that both female and male volleyball players were mostly born in the first quarter of the year. On the other hand, relative age was not a distinctive effect on performance variables of young volleyball players in the same chronological age

Estimating the volleyball team ranking in the 2016 Rio Olympics by artificial neural network and linear model: Yapay sinir ağları ve doğrusal model ile 2016 Rio Olimpiyatlarındaki voleybol takım sıralamasının tahmin edilmesi

This study was conducted to estimate the Olympic ranking of the games played in the qualifying groups by the countries that were qualified for the 2016 Rio Olympics in volleyball branch by analyzing with the developed artificial neural networks (ANN) and linear equation model. In the study, the difficulty level of all games (n=324) that total 22 teams played in the qualifying for the 2016 Rio Olympics in volleyball branch (11 female and 11 male volleyball teams)  and International Volleyball Federation (FIVB) ranking score was evaluated separately. Feedforward network structure having two hidden layers in the modeling with ASS developed for 9 different input variables was preferred in the study. In addition, linear modeling method, which provides an easier calculation than artificial neural networks, was performed by “regress” instruction in MATLAB. In the female group, the percentage mean error value of the models was calculated as 18.86 by ANN model, and as 4.53 by linear model. In male groups, it was calculated as 19,34 by ANN model, and as 0,74 by linear model. According to the modeling results obtained in the study, both female and male volleyball teams’ results were modeled with a higher accuracy by linear model. As a result, team rankings of the volleyball branch in the women's group in the 2016 Rio Olympic Games was estimated with an accuracy over 98% separately by ANN modeling regression results and linear modeling regression results. In men’s volleyball games, it was estimated with an accuracy over 98% by ANN modeling regression results, and with an accuracy over 99% by linear modeling regression results. It can be stated that the difficulty level of the games that countries participating in Olympics in volleyball branch played in the qualifying groups and FIVB ranking scores are among the variables that have a significant effect on determining the Olympic ranking. ​Extended English summary is in the end of Full Text PDF (TURKISH) file.   Özet   Bu çalışma 2016 Rio Olimpiyatlarına voleybol branşından katılma hakkı kazanan ülkelerin eleme gruplarındaki maçlarının, geliştirilen yapay sinir ağları (YSA) ve doğrusal eşitlik modeli ile analiz edilerek olimpiyat sıralamasının tahmin edilmesi amacı ile yapılmıştır. Çalışmada 2016 Rio Olimpiyatlarına voleybol branşından katılan (11 kadın ve 11 erkek voleybol takımı) toplam 22 takımın grup elemelerinde oynadığı tüm maçlar (n=324) zorluk derecesi ve Uluslararası Voleybol Federasyonu (FIVB) sıralama puanı göz önüne alınarak değerlendirilmiştir. Çalışmada dokuz farklı giriş değişkenine göre geliştirilen YSA modeli  ile modellemede iki gizli katmana sahip ileri yayılımlı ağ yapısı tercih edilmiştir. Ayrıca çalışmada YSA’na göre çok daha basit bir hesaplama sağlayan doğrusal modelleme yöntemi de, MATLAB’de bulunan “regress” komutu ile gerçekleştirilmiştir. Kadınlar grubunda; test verilerine bakıldığında modellerin yüzde ortalama hata değeri, YSA modelinde 18.86, doğrusal modelde 4.53 olarak; erkekler grubunda ise YSA modelinde 19.34, doğrusal modelde 0.74 olarak hesaplanmıştır. Çalışmada elde edilen modelleme sonuçlarına göre; hem kadın hem de erkek voleybol takımlarının sonuçları doğrusal model ile daha yüksek doğrulukla modellenmiştir. Sonuç olarak, kadınlar kategorisinde 2016 Rio Olimpiyat Oyunlarında voleybol branşının takım sıralaması, YSA modelleme regresyon sonuçları ve doğrusal modelleme regresyon sonuçları ile ayrı ayrı %98’in üstünde doğrulukla tahmin edilmiştir. Erkek voleybol maçlarında ise YSA modelleme regresyon sonuçları %98’in üstünde, doğrusal modelleme regresyon sonuçları ise %99’un üstünde doğrulukla tahmin edilmiştir. Voleybolda Olimpiyatlara katılan ülkelerin eleme gruplarında oynadıkları maçların zorluk derecesi ve FIVB sıralama puanlarının Olimpiyat sıralamasının belirlenmesine önemli etkisi olan değişkenlerden olduğu söylenebilir

The relationship between isokinetic knee flexion and extension muscle strength, jump performance, dynamic balance and injury risk in female volleyball players

The relationship between balance, knee muscle strength, jump height and risk of injury has not been clearly stated in female volleyball athletes. The study was to determine whether a correlation exists between knee joint isokinetic muscle strength, risk of injury, balance and jump height in female volleyball athletes. Twenty-two female volleyball athletes were involved into the study. Knee muscle strength were evaluated with the Biodex 3® isokinetic dynamometer. Jump performances were evaluated with the countermovement (CMJ) jump test using the Vert Jump® Motion Sensitive Sensor. The injury risk for all players were evaluated by the Functional Movement Screen (FMS®). Balance measurements were performed with a dynamometer Biodex Systems 3® device. There was a significant relationship between CMJ height, knee flexion and extension peak torque and H:Q ratio values at two angular velocities, dynamic balance and total FMS® scores (p.05). We suggest that all clinicians and coaches involved in the protective and preventive rehabilitation phase evaluate these parameters and plan their training programs in line with the results obtained in increasing both individual and team performance of athletes

ELİT BAYAN VOLEYBOLUNDA MAÇ SONUCUNU AÇIKLAYAN DEĞİŞKENLERİN LOJİSTİK REGRESYON YÖNTEMİ İLE BELİRLENMESİ VE MAÇ KAZANMAYA YÖNELİK OLASILIK MODELİNİN TAHMİNİ

Bu çalışmada, Türkiye 1. Bayanlar Voleybol Ligi verileri esas alınarak, müsabaka sonucunu belirleyen değişkenlerin tespiti, etki dereceleri, müsabaka kazanma bahis oranları ve olasılıklarını tahmin eden yeni model önerileri geliştirilmiştir. Çalışmadaki değişkenler etkinlik ve teknik elementler olarak iki grupta ele alınmıştır. Etkinlik Modeli değişkenleri olarak Libero Etkinliği (LE), Pasör Etkinliği (PE), Orta Oyuncu Etkinliği (OOE), Pasör Çaprazı Etkinliği (PCE) ve Dört Numara Etkinliği (N4E) alınmıştır. Teknik Elementler Modeli değişkenleri ise Set Başına Servisten Alınan Sayı (SBSAS), Set Başına Bloktan Alınan Sayı (SBBAS), Set Başına Toplam Manşet Hatası (SBTMH), Set Başına Toplam Hücum Hatası (SBTHH), Set Başına Toplam Hücumdan Alınan Sayı (SBTHAS) ve Set Başına Kaçırılan Servis Sayısı (SBKSS) dikkate alınmıştır. Bu bağlamda, model bağımlı değişkeni Maç sonucu kazanan-kaybeden (1-0) olarak tanımlanmış olup, etkinlik modeli ve teknik elementler modeli lojistik regresyon formunda oluşturularak tahmin edilmiştir. Araştırma örneklemini 2008–2009 yılında Türkiye 1. Bayanlar Voleybol Liginde bulunan 12 takım arasından play-off oynamaya hak kazanan ilk 8 takımın müsabaka verileri oluşturmuştur. Bu takımların, 54 tanesi Türkiye ligi, 20 tanesi play-off, 6 tanesi Türkiye kupası, 2 tanesi şampiyonlar ligi olmak üzere toplam 82 maçına ilişkin 164 gözlemden (oyun) hareketle analizler gerçekleştirilmiştir. Etkinlik Modelinde tüm değişkenler, Teknik Elementler Modelinde SBKSS hariç diğer değişkenler maç sonucunu açıklamada anlamlı bulunmuştur. Çalışmada oluşturulan modellerden Etkinlik Modeli, maç sonucunu %87.65 olasılıkla doğru tahmin ederken; Teknik Elementler Modeli maç sonucunu %84.66 olasılıkla doğru tahmin etmiştir. Tahmin edilen lojistik regresyon modelleri aynı zamanda kazanma-kaybetmeye ilişkin bahis, bahis oranları ve olasılıkların da tahmin edilmesine imkan sağlamaktadır.Based on the Turkey First Woman Volleyball League data, in this study, new model suggestions are developed for determination of the variables defining the bout results and estimation the effect levels, odds ratio and probabilities of the achivement in the matches. In this study variables are divided into two groups; efficiency and technical elements. For the Efficiency Model variables, Libero Efficiency (LE), Setter Efficiency (PE), Middle Blocker Efficiency (OOE), Opposite (Universal Player) Efficiency (PCE) and Number Four Efficiency (N4E) are taken. For the variables of Technical Elements Model, Serve Score Per Set (SBSAS), Block Score Per Set (SBBAS), Serve Reception Error Per Set (SBTMH), Total Attack Error Per Set (SBTHAS), Missed Serve Score Per Set (SBKSS) are taken into consideration. In this sense, model dependent variable is defined as Match result winner-loser (1-0) and estimated in the logistic regression form of the efficiency model and technical elements model. Research samples include the match data of the top 8 team which gain a right for play-off among the 12 teams in the 2008-2009 Turkey First Woman Volleyball League. Analyses is done from 164 observation (game) regarding total 82 match; 54 Turkey league, 20 playoff, 6 Turkish Cup, 2 champions league. All variables in the Efficiency Model and other variables except from the Missed Serve Score Per Set (SBKSS) in the Technical Elements Model are meaningful for the match result explanation. From the models formed in this study Efficiency Model estimates the match result right with 87.65 percent; Technical Elements Model estimates the match result right with 84.66 percent. Estimated logistic regression models provide opportunity for estimation of the odds regarding winning-losing, odds ratios and probabilities

Evaluation of Postural Balance and Hamstring/Quadriceps Peak Torque Ratios According to Leg Dominancy in Turkish Female Volleyball Players

Objective: The aim of the study is to determine hamstring/quadriceps (H/Q) strength ratio, peak torque (PT), and postural balance (PB) in dominant (D) and non-dominant (ND) legs in Turkish female volleyball players. Methods: This cross-sectional study included 63 Turkish Women’s Volleyball 1st league players with a mean age of 21.9±4.4 yr, mean height of 182.0±5.9 cm and mean body weight of 66.5±8.3 kg. Dynamic balance measurements were performed for 20 seconds and three repetitions for each leg. Overall stability index (OSI), anterior/posterior stability index (APSI) and medial/lateral stability index (MLSI) data were collected. Afterwards, hamstrings and quadriceps PT was measured with an isokinetic dynamomoter for concentric/concentric (con/con) contractions at both speeds of 60˚/s and 180˚/s. Wilcoxon Test was used for statistical analysis. Results: Statistically significant difference was found for quadriceps muscles’ PT between dominant or non-dominant legs at 60˚/s. H/Q ratios were found lower in the dominant leg, with statistical significance at 60˚/s. No statistically significant difference was found for OSI, APSI and MLSI between dominant and non-dominant legs. Discussion: H/Q ratios increase with higher angular velocity. Also, there are statistically significant differences in PT and H/Q ratio at 60˚/s between dominant and non-dominant legs. These findings may indicate that the non-injured leg can not be used as a reference for the injured leg in case of injury in female volleyball players, regardless of which leg is involved

Monitoring of training internal load perceived difficulty and fitness status of elite volleyball players

Bu çalışmanın amacı, elit kadın voleybolcuların antrenmanlarda içsel yük Algılanan Zorluk Derecesi (AZD) değerleri ve zindelik durumu değerlerinin aylık olarak takip edilmesidir. Çalışmaya Vestel Venüs Sultanlar Lig’inde oynayan 15 kadın (yaş=26.4 ± 3.43) voleybolcu gönüllü olarak katılmıştır. Katılımcıların zindelik durumları; zindelik durum anketi, antrenman içsel yükleri; AZD anketi ile 16 hafta boyunca kaydedilmiştir. Çalışmadaki verilerin analizinde, tekrarlı ölçümler arasındaki farklılıkları belirlemede, nonparametrik testlerden Friedman testi kullanılmış, ölçümler arasındaki fark ise Wilcoxon testi ile belirlenmiştir. Yapılan istatistiksel analiz sonuçlarına göre voleybolcuların aylık zindelik durumlarının tekrarlanan ölçümleri arasında 1. ay ile 2. ay arasında 2. ay lehine; 1. ay ile 4. ay arasında 4. ay lehine; anlamlı bir fark tespit edilmiştir. Buna karşın antrenman içsel yük, AZD’nin tekrarlanan ölçümlerinde aylar arasında anlamlı fark olmadığı belirlenmiştir. Elit bir voleybol takımının sezon boyunca yoğun antrenman ve maç takvimleri göz önünde bulundurulduğunda sporcuların antrenman yüklerinin kolay bir şekilde uygulanan ve hızlı sonuç veren zindelik durum ve AZD anketleri ile takip edilmesi antrenman periyotlamasına yön veren önemli bir parametre olabilir.The aim of this study was to monitor the internal load perceived difficulty values (AZD) and fitness status values of elite female volleyball players in training on a monthly basis. 15 athletes (age=26.4 ± 3.43) from a womens volleyball team competing in the Vestel Venus Sultans League in the 2018-2019 season participated in the study voluntarily. The fitness status of the participants; fitness status scale, training internal loads; It was recorded with the RPE scale for 16 weeks. In the analysis of the data in the study, the Friedman test, which is one of the nonparametric tests, was used to determine the differences between repeated measurements, and the difference between the measurements was determined by the Wilcoxon test. According to the statistical analysis results, among the repeated measurements of the monthly fitness of volleyball players between the 1st month and the 2nd month in favor of the 2nd month; between the 1st month and the 4th month in favor of the 4th month; a significant difference was detected. On the other hand, it was determined that there was no significant difference between the months in the repeated measurements of training internal load RPE. Considering the intense training and match schedules of an elite volleyball team throughout the season, monitoring the training loads of the athletes with fitness status and RPE surveys that are applied easily and give fast results can be an important parameter that guides the training period