| Abstract | Uvod: Plesači klasičnoga baleta mogu se smatrati sportašima obzirom na visoke fizičke zahtjeve prilikom izvođenja aktivnosti, a koji se najviše odražavaju na mišićno-koštani sustav. Balet zahtijeva visoku razinu tehničkih vještina radi čega su plesači izloženi izuzetno velikom volumenu treninga, ali i nastupa. Posljedično tome prisutna je velika pojavnost ozljeda. U dosadašnjoj znanstvenoj literaturi opisani su brojni čimbenici koji se povezuju s rizikom od nastanka ozljeda u profesionalnih plesača. Smatra se da je taj rizik multifaktorski, te da nastanku ozljeda pridonosi kombinacija i interakcija intrinzičnih (specifičnih za pojedinog plesača) i ekstrinzičnih (okolišnih) čimbenika, a koji se mogu ili ne mogu mijenjati. S obzirom da je, sukladno značajnim fizičkim opterećenjima, visoka razina tjelesnih sposobnosti preduvjet za bavljenje ovom profesijom, u kontekstu rizičnih čimbenika za nastanak ozljeda istražuju se i sastavnice tjelesnog fitnesa. Istraživanja o ozljedama plesača klasičnog baleta započela su tek
unatrag nekoliko desetljeća. Međutim, prije nego li je osnovana International association for dance medicine and science (IADMS), nisu postojali standardizirani pristupi u istraživanju ozljeda u plesača. Dakle, stopu incidencije ozljeda za plesače klasičnog baleta bilo je teško ustanoviti bez jedinstvenih standarda za mjerenje ili definiranje ozljeda, te standardne
metodologije za bilježenje izloženosti radnom opterećenju, tj. stvarnom broju sati provedenih u plesnim aktivnostima. Dosadašnja istraživanja koja su se bavila povezanošću tjelesnog fitnesa s pojavnošću ozljeda uzimala su u obzir relativno manji broj ispitanika, plesače amatere, plesače različitih plesnih stilova ili studente baleta, dok je manji broj ispitivanja proveden na
profesionalnim plesačima klasičnog baleta i s longitudinalnim praćenjem. Također, uglavnom je istraživana razina tjelesnih sposobnosti na samom početku plesne sezone. Glavni cilj ove disertacije je stoga bio utvrditi povezanost sastavnica zdravstvenog fitnesa (sastav tijela, fleksibilnost, mišićni fitnes i aerobni fitnes) u fazi očekivane najveće pripremljenosti s pojavnošću ozljeda plesača u jednoj godini. Ispitanici i metode: Istraživanje je uključilo prigodan uzorak ispitanika profesionalnih plesača klasičnog baleta, članove ansambla Hrvatskog narodnog kazališta (HNK) u Zagrebu (N=40). Od ukupnog broja ispitanika 26 je bilo ženskoga spola (dob (aritmetička sredina ± SD) 32,2±7,9 godina, tjelesna visina 166,1±4,3 cm, tjelesna masa 52,6±5,4 kg), a 14 muškoga spola (29,7±7,4 godina, 177,9±4,8 cm, 69,5±7,0 kg) dobi u rasponu od 21 do 45 godina. Testirane su sastavnice zdravstvenog fitnesa: sastav tijela, aerobni fitnes, fleksibilnost, mišićni fitnes. Za određivanje sastava tijela (postotka masnog tkiva) koristila se metoda mjerenja sedam kožnih nabora. Za procjenu aerobnog tj. kardiorespiracijskog fitnesa korišten je Åstrand-Ryhming test submaksimalnog opterećenja na biciklergometru. Za određivanje fleksibilnosti goniometrom je
mjeren opseg pokreta u zglobu kuka te gornjem gležanjskom zglobu. Mišićni fitnes je procijenjen provođenjem testa upora na podlakticama (izdržljivost mišića trupa), sklekova (jakost i izdržljivost mišića gornjeg dijela tijela), testa skoka u vis na platformi (eksplozivna snaga mišića donjih ekstremiteta), testa ponavljanih skokova na platformi (izdržljivost donjih ekstremiteta). Pratio se izostanak iz profesionalnih aktivnosti, jer je to bio kriterij definiranja ozljede te vrsta i težina ozljede. Navedene varijable procjenjivane su u jednogodišnjem periodu te je utvrđena povezanost stope incidencije ozljeda sa sastavnicama zdravstvenog fitnesa procijenjenog u razdoblju očekivane najveće pripremljenosti, definiranom kao razdoblje sredine sezone kada je opterećenje predstavama najveće, što ujedno podrazumijeva najzahtjevniji broj proba i vježbi. Statistička obrada podataka uključila je deskriptivnu analizu svih mjerenih varijabli, normalnost distribucije varijabli testirana je Kolmogorov-Smirnovljevim testom, za povezanost između sastavnica zdravstvenog fitnesa i broja ozljeda korištena je multipla regresijska analiza, a za utvrđivanje razlika u razini sastavnica zdravstvenog fitnesa između skupina ispitanika (kategoriziranih prema težini ozljede i prema položaju u ansamblu) te razlika u stopi incidencije ozljeda prema spolu i položaju u ansamblu korišten je Studentov t-test. Statistička značajnost testirana je uz pogrešku od 0,05. Rezultati: Stopa incidencije ozljeda za ansambl u promatranom jednogodišnjem razdoblju iznosila je 0,71 na 1000 plesača-izloženosti (95%-tni interval pouzdanosti 0,46-1,06). Regresijskom analizom utvrđena je značajna povezanost indeksa tjelesne mase, opsega vanjske rotacije natkoljenice u lijevom kuku, prosječne snage odraza u ponavljanim skokovima u 45 s te broja sklekova s pojavnošću ozljeda kod ispitanika, pri čemu prediktorski model objašnjava 57% varijance pojavnosti ozljeda (p<0,001). Ispitanici koji su u periodu praćenja zadobili lake ozljede imali su statistički značajno veći opseg dorzalne fleksije oba stopala u odnosu na ispitanike koji su zadobili teže ozljede (17,4° naprema 12,9° za desno stopalo (p=0,019), odnosno 16,4° naprema 12,8° za lijevo stopalo (p=0,020)). Razlika u stopi incidencije ozljeda
između skupina ispitanika prema spolu (0,60 na 1000 plesačica-izloženosti naprema 0,94 na 1000 plesača-izloženosti) i prema položaju u ansamblu (0,86 na 1000 solista-izloženosti naprema 0,60 na 1000 članova ansambla-izloženosti) nije bila statistički značajna (p=0,266 i p=0,367, redom). U procjeni razine sastavnica zdravstvenog fitnesa, solisti su u odnosu na ostale članove ansambla imali značajno bolji rezultat samo u testu upora na podlakticama (46,8 naprema 36,0 s (p=0,042) i u skoku uvis s mjesta (46,9 naprema 40,5 cm (p=0,040)).mZaključak: Rezultati ovog istraživanja ukazuju da su sastavnice zdravstvenoga fitnesa (sastav tijela, fleksibilnost i mišićni fitnes) u razdoblju najveće pripremljenosti povezane s pojavnošću ozljeda plesača i plesačica klasičnoga baleta. Od ispitivanih sastavnica zdravstvenoga fitnesa, jedino se fleksibilnost u skočnom zglobu značajno razlikovala između skupina ispitanika kategoriziranih prema težini ozljede. Solisti su imali značajno bolju mišićnu izdržljivost
gornjeg dijela tijela i eksplozivnu snagu donjih esktremiteta u odnosu na ostale članove ansambla. Stope incidencije ozljeda između skupina ispitanika prema spolu te prema položaju unutar ansambla nisu se statistički značajno razlikovale. Na osnovi dobivenih rezultata, ovo istraživanje moglo bi poslužiti kao temelj za izradu smjernica programa kondicijske pripreme i
prevencije ozljeda u profesionalnih plesača klasičnoga baleta. |
| Abstract (english) | Introduction: Classical ballet dancers can be considered athletes due to the high physical demands when performing dance activities, mostly reflected on the musculoskeletal system. Ballet requires a high level of technical skills, exposing dancers to an extremely high volume of training and performances. As a result, there is a high incidence of injuries. In the previous studies, numerous factors have been described that are associated with the risk of injury in professional dancers. It is considered that this risk is multifactorial, and that the combination and interaction of intrinsic (specific to the individual dancer) and extrinsic (environmental) factors, which may or may not be changed, contribute to the occurrence of injuries. Given that in accordance with significant physical loads, a high level of physical abilities is a prerequisite for practicing this profession, in the context of risk factors for the occurrence of injuries, components of physical fitness are also investigated. Research on the injuries of classical ballet dancers began only a few decades ago. However, before the International association for dance medicine and science (IADMS) was founded, there was no standardized approach to the research of injuries in dancers. Thus, the rate of injuries for classical ballet dancers was difficult to establish without uniform standards for measuring or defining injuries, and a standard methodology for recording exposure to workload, i.e., the actual number of hours spent in dance activities. Previous studies on relationship between physical fitness and the occurrence of
injuries were performed on relatively small number of subjects, amateur dancers, dancers of different dance styles or ballet students, while a smaller number of studies was conducted on professional classical ballet dancers and with longitudinal monitoring. Thus, the main goal of this dissertation was to determine the connection between the components of physical fitness (body composition, flexibility, muscle fitness and aerobic fitness) in the period of expected highest preparedness with the occurrence of injuries in professional ballet dancers in one year. Participants and methods: The research included a convenient sample of professional ballet dancers, members of the ensemble of the Croatian National Theater (CNT) in Zagreb (N=40). Out of the total number of respondents, 26 were females (age (arithmetic mean ± SD) 32.2±7.9 years, body height 166.1±4.3 cm, body weight 52.6±5.4 kg) and 14 were males (29.7±7.4 years, 177.9±4.8 cm, 69.5±7.0 kg), aged between 21 and 45 years. Components of physical fitness were tested: body composition, aerobic fitness, flexibility, muscle fitness. The seven-skinfold method was used to determine body composition (percentage of body fat). Åstrand-Ryhming cycle ergometer submaximal test was used to assess aerobic, i.e., cardiorespiratory, fitness. To determine flexibility, the range of motion in the hip joint and ankle joint was measured by goniometer. Muscular fitness was assessed by performing a forearm plank test (trunk muscle endurance), push-ups (upper body muscle strength and endurance), vertical jump test (lower extremity muscle explosive power), and repeated jump test (lower extremity endurance). Absence from professional activities (criterion for defining an injury) as well as the type and severity of the injury, were monitored. The aforementioned variables were evaluated over a one-year period, and a relationship was determined between injury incidence rate and the components of physical fitness assessed in the period of expected greatest preparedness, defined as the mid-season period in which the performance load is the highest, which also implies the most demanding number of rehearsals and classes. Statistical data analysis included a descriptive analysis of all measured variables, the normality of the distribution of variables was tested with the Kolmogorov-Smirnov test, multiple regression was used to test the relationship between physical fitness components and the number of injuries, and Student t-test was used to determine differences in the level of physical fitness components between groups of participants (categorized according to the severity of injuries and according to the position in the ensemble) as well as the difference in the injury incidence rate according to gender and position in the ensemble. The level of statistical significance was set at 0.05. Results: The injury incidence rate for the ensemble in the monitored one-year period was 0.71 per 1000 dancers-exposure (95% confidence interval 0.46-1.06). Regression analysis showed a significant correlation between body mass index, range of external rotation of the thigh in the left hip, average take-off power in repeated jumps in 45 seconds and the number of push-ups with the occurrence of injuries in participants, with the predictor model explaining 57% of the variance of injury incidence (p<0.001). The participants who suffered minor injuries during the observed period had a statistically significantly larger range of dorsal flexion of both feet compared to participants who suffered more serious injuries (17.4° vs 12.9° for the right foot (p=0.019) and 16.4° vs 12.8° for the left foot (p=0.020)). The difference in the injury incidence rate between female and male participants (0.60 per 1000 female dancers-exposures vs. 0.94 per 1000 male dancers-exposures) and according to the position in the ensemble (0.86 per 1000 soloist dancers-exposure vs. 0.60 per 1000 members of the ensemble-exposure) was not statistically significant (p=0.266 and p=0.367, respectively). In assessment of the level of health-related fitness components, soloists had significantly better results compared to the members of corps-de-ballet only in plank test (46.8 vs 36.0 s (p=0.042) and in the vertical jump test (46.9 vs 40.5 cm (p=0.040)).
Conclusion: The results of this research indicate that the components of health-related fitness (body composition, flexibility and muscle fitness) in the period of expected highest preparedness are associated with the occurrence of injuries in dancers of classical ballet. Of the tested components of health-related fitness, only ankle flexibility significantly differed between groups of subjects categorized according to the severity of injuries. The soloists had significantly better muscular endurance of the upper body and explosive strength of the lower extremities compared to corps-de-ballet dancers. Injury incidence rates between groups of subjects by sex and position within the ensemble did not show statistically significant difference. Based on the obtained results, this research could serve as a basis for the development of guidelines for physical conditioning and injury prevention programs in professional classical ballet dancers. |
