Optimal training load for the hang clean and squat jump in u-21 rugby players

De Villiers, Nico (2011-12)

Thesis (M Sport Sc)--Stellenbosch University, 2011.

Thesis

ENGLISH ABSTRACT: This study investigated the optimal training load required for peak-power production in two types of exercises, namely an Olympic-type and a ballistic exercise. The hang clean and the squat jump were selected to represent these two types of exercise. It was ascertained whether a change in strength levels and training status will have an effect on the optimal loads for peak-power production of rugby players. In addition, the influence that different playing positions have on power production was also investigated. Fifty-nine under-21 male rugby players (Mean Age 19.3yrs; SD ± 0.7yr) from two rugby academies, performed a maximal-strength test in the hang clean and squat, followed by a power test in the hang clean and squat jump with loads ranging from 30 to 90% of maximal strength (1RM). Testing was conducted in the pre-season phase and repeated during the inseason phase. Peak power for the hang clean was achieved at 90% 1RM in the pre-season and at 80% 1RM during the in-season. Peak power for the squat jump was achieved at 90% 1RM in the pre-season. However, this location of the optimal loading was not significantly higher than that of the other loadings (60, 70 and 80% 1RM). During the in-season, peak power for the squat jump was reached at 90% 1RM. Here again, the optimal-loading location was not significantly higher than that of the other loadings (50, 60, 70 and 80% 1RM). It was concluded that the optimal load for power production is 90% 1RM for the hang clean and 60-90% for the squat jump. It was found that an improvement in strength levels of the subjects affected both peak-power production and the optimal load in both exercises. During the in-season peak power in the hang clean was reached at 80% 1RM, and at 50% 1RM for the squat jump. There were no significant differences in the performances of subjects from different playing positions (forwards versus backline players). In the hang clean, peak-power production seems to be reliant on increased strength and results in peak-power output at high loads. The squat jump, on the other hand, is more reliant on velocity due to its ballistic nature and is possibly better suited to developing power at lighter loadings. Because it produces peak power at a lower percentage load than the hang clean, the squat jump could be more effective in power development for players who are inexperienced in power training. Long-term exercise periodisation in power training can therefore be employed progressively from simpler exercises (e.g., squat jump) using only the legs, to more complex exercises (e.g., Olympic-lifting) that involve the whole body. This study confirmed that the specific requirements of different sport codes should be considered meticulously before selecting and prescribing exercises and loads for power-training programmes.

AFRIKAANSE OPSOMMING: Die hooffokus van hierdie studie was op die optimale oefenlading wat vereis word vir die produsering van piek-profkrag tydens die uitvoering van twee tipes oefening, naamlik ’n Olimpiese- en ’n ballistiese oefening. Die hang clean en die squat jump is geselekteer om bogenoemde twee tipes oefening te verteenwoordig. Daar is bepaal of ’n verbetering van die krag-vlakke en oefenstatus van rugbyspelers ’n invloed het op die optimale ladings vir piek-plofkrag ontwikkeling. Verder is die moontlike rol van verskillende speelposisies ondersoek. Nege-en-vyftig onder-21 mans-rugbyspelers (M-ouderdom 19.3jr; SD ± 0.7jr) vanuit twee rugbyakademies het ’n maksimale-krag toets in die hang clean en squat uitgevoer. Dit is opgevolg deur ’n plofkrag-toets in die hang clean en squat jump met ladings wat gewissel het van tussen 30 en 90% van maksimale werkverrigting (1RM). Toetsing het plaasgevind in die voor-seisoen fase en is herhaal tydens die daaropvolgende speelseisoen. Piek-plofkrag vir die hang clean is bereik tydens ’n oefenlading van 90% 1RM in die voor-seisoen en by 80% 1RM later in die speelseisoen. Piek-plofkrag vir die squat jump is behaal by 90% 1RM in die voor-seisoen fase. Hierdie optimale lading-lokasie was egter nie beduidend hoër as by die ander ladings van 60, 70 en 80% 1RM nie. Tydens die speelseisoen is piek-plofkrag bereik in die squat jump by 90% 1RM. Die optimale lading-lokasie was weereens nie beduidend hoër as by die ander ladings van 50, 60, 70 en 80% 1RM nie. Daar is tot die gevolgtrekking gekom dat die optimale oefenlading vir die ontwikkeling van piek-plofkrag vir die hang clean 90% 1RM is, en 60% vir die squat jump. Daar is ook gevind dat ’n verbetering in kragvlakke van die toetslinge, beide piek-plofkrag-produksie en die optimale oefenbelading in albei oefeninge beïnvloed. Tydens die speelseisoen is piek-plofkrag behaal in die hang clean by 80% 1RM, en by 50% 1RM in die squat jump. Geen beduidende verskille in werkverrigting is gevind tussen toetslinge uit verskillende speelposisies (voorspelers versus agterlyn-spelers) nie. Dit blyk dat in die hang clean, die produksie van plofkrag beïnvloed word deur ’n verbetering in krag en dat dit tot hoër optimale ladings vir piek-plofkrag produksie lei. Die squat jump, in teenstelling, is meer afhanklik van snelheid en is moontlik beter geskik vir die produsering van plofkrag teen ligter oefenladings. Omdat die squat jump piek-plofkrag genereer teen laer ladings as die hang clean, kan dit meer effektief wees vir spelers met gebrekkige ervaring in krag-oefening. Lang-termyn oefen-periodisering in plofkrag-oefening kan gevolglik progressief aangewend word vanaf eenvoudiger oefeninge (bv. squat jump), waar slegs die bene gebruik word, tot meer komplekse oefeninge (bv. Olimpiese-gewigoptel) waar die hele liggaam betrek word. Hierdie studie bevestig dat die spesifieke vereistes van verskillende sportkodes deeglik oorweeg moet word alvorens oefeninge en ladings geselekteer en voorgeskryf word vir plofkrag-programme.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/17976
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