Thesis (M Sport Sc)--Stellenbosch University, 2011. / 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.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/17976 |
| Date | 12 1900 |
| Creators | De Villiers, Nico |
| Contributors | Venter, Ranel, Stellenbosch University. Faculty of Education. Dept. of Sport Science. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | xiv, 145 p. :ill. (some col.) |
| Rights | Stellenbosch University |
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