Although the available literature mentions a variety of anthropometric performance determinants for gymnastics, no one has until now made an attempt to determine the performance determinants of more advanced, young, South African (SA), female gymnasts. The purposes of this study were, therefore, firstly to determine the anthropometric variables that differ significantly @ 5 0,05) between successful and less successful young, SA, female gymnasts in the vault and floor item and secondly, to determine the anthropometric variables that contribute to the performance of young, SA, female gymnasts in the vault and floor item. Twelve young, female gymnasts (13,39 f 2,14 years) from a gymnastics club in the North-West Province of South Africa participated in this study. Only gymnasts who participated at level 6-9 and junior as well as senior olynlpic level were selected to participate in this study. Sixty one anthropometric variables were measured on the dominant side of the body according to the methods of Norton et al. (1996). Firstly, the descriptive statistics (means and standard deviations) of the gymnastics population were calculated. This was followed by an analysis which intended to arrange the gymnasts in a ranking order according to the vault and floor performances (marks) that were reached during the South African Gymnastics Championships. Due to differences in the participation level, data was normalised by making use of correction factors. Independent t-tests and effect sizes revealed that the gymnasts who obtained the highest marks (top 5) during the execution of the vault and floor item during the South African Gymnastics Championships had statistical and practical significantly (p 5 0,05) larger relaxed and flexed upper arm, wrist and ankle circumferences as well as mesomorph values than the less successful gymnasts. The cluster analysis-reduced variables were used to perform a forward, stepwise multiple regression analysis which showed that flexed upper arm (53,93%) and chest circumference (3,6996); midstillion dactillion (12,38%), trochanterion-tibia1 lateral (5,77%) and foot length (1 1,50%); fat percentage (8,93%), ectomorphy (l,96%), bideltoied breadth (1,54%), triceps skinfold (0,23%) and iliospinal box height (0,07%) contributed 100% to the variance in gymnasts' vault performances. Bi-trochanterion- (34,86%), femur- (17,07%) and bi-deltoied breadth (4,93%); front thigh skinfold (19,71%); fat percentage (7,68%); acromial-radial (4,09%) and foot length (0,05%) as well as waist- (6,68%), chest- (2,92%) and gluteal thigh circumference (2;02%) were the anthropometric variables which contributed 100% to the variance in gymnasts' floor performances. Flexed upper arm circumference, fat percentage, ectomorphy, iliospinal box height and bitrochanterion and femur breadth as well as gluteal thigh circumference and foot length were, however, the only anthropometric variables which contributed significantly to gymnasts' vault and floor performances, respectively. The conclusion that can, therefore, be drawn is that larger upper arm and upper body circumferences; hand, foot, upper and total leg lengths; triceps skinfolds, fat percentages and ectomorphy as well as larger limb and torso circumferences; waist breadths; fat percentages and front thigh skinfolds as well as upper arm and foot lengths are the respective, important anthropometric vaulting and floor performance determinants for young, South African, female gymnasts and should be included in the sport scientific testing protocols of gymnasts. / Thesis (M.Sc. (Human Movement Science))--North-West University, Potchefstroom Campus, 2007.

Although the available literature mentions a variety of anthropometric performance determinants for gymnastics, no one has until now made an attempt to determine the performance determinants of more advanced, young, South African (SA), female gymnasts. The purposes of this study were, therefore, firstly to determine the anthropometric variables that differ significantly @ 5 0,05) between successful and less successful young, SA, female gymnasts in the vault and floor item and secondly, to determine the anthropometric variables that contribute to the performance of young, SA, female gymnasts in the vault and floor item. Twelve young, female gymnasts (13,39 f 2,14 years) from a gymnastics club in the North-West Province of South Africa participated in this study. Only gymnasts who participated at level 6-9 and junior as well as senior olynlpic level were selected to participate in this study. Sixty one anthropometric variables were measured on the dominant side of the body according to the methods of Norton et al. (1996). Firstly, the descriptive statistics (means and standard deviations) of the gymnastics population were calculated. This was followed by an analysis which intended to arrange the gymnasts in a ranking order according to the vault and floor performances (marks) that were reached during the South African Gymnastics Championships. Due to differences in the participation level, data was normalised by making use of correction factors. Independent t-tests and effect sizes revealed that the gymnasts who obtained the highest marks (top 5) during the execution of the vault and floor item during the South African Gymnastics Championships had statistical and practical significantly (p 5 0,05) larger relaxed and flexed upper arm, wrist and ankle circumferences as well as mesomorph values than the less successful gymnasts. The cluster analysis-reduced variables were used to perform a forward, stepwise multiple regression analysis which showed that flexed upper arm (53,93%) and chest circumference (3,6996); midstillion dactillion (12,38%), trochanterion-tibia1 lateral (5,77%) and foot length (1 1,50%); fat percentage (8,93%), ectomorphy (l,96%), bideltoied breadth (1,54%), triceps skinfold (0,23%) and iliospinal box height (0,07%) contributed 100% to the variance in gymnasts' vault performances. Bi-trochanterion- (34,86%), femur- (17,07%) and bi-deltoied breadth (4,93%); front thigh skinfold (19,71%); fat percentage (7,68%); acromial-radial (4,09%) and foot length (0,05%) as well as waist- (6,68%), chest- (2,92%) and gluteal thigh circumference (2;02%) were the anthropometric variables which contributed 100% to the variance in gymnasts' floor performances. Flexed upper arm circumference, fat percentage, ectomorphy, iliospinal box height and bitrochanterion and femur breadth as well as gluteal thigh circumference and foot length were, however, the only anthropometric variables which contributed significantly to gymnasts' vault and floor performances, respectively. The conclusion that can, therefore, be drawn is that larger upper arm and upper body circumferences; hand, foot, upper and total leg lengths; triceps skinfolds, fat percentages and ectomorphy as well as larger limb and torso circumferences; waist breadths; fat percentages and front thigh skinfolds as well as upper arm and foot lengths are the respective, important anthropometric vaulting and floor performance determinants for young, South African, female gymnasts and should be included in the sport scientific testing protocols of gymnasts. / Thesis (M.Sc. (Human Movement Science))--North-West University, Potchefstroom Campus, 2007.

Lower body explosive power (LBEP) forms a critical component in any individual and team sport performance and it is therefore essential to develop a means of predicting LBEP in adolescents for early identification of future talent in various sporting codes. LBEP is frequently used by athletes during matches or competitions where explosive movements such as jumping, agility running and sprinting are required for successful performance. These movements are usually found in individual sports such as long jump and high jump as well as in team sports such as basketball, volleyball and soccer. To date not much literature is available on LBEP, especially with regard to LBEP prediction models. Furthermore, studies on adolescents are scarce and a LBEP prediction model has not yet been developed for a South African adolescent population. It is against this background that the objectives of this study were firstly, to develop a LBEP prediction model from various physical and motor performance components among a cohort of adolescents living in the Tlokwe local municipality of Dr Kenneth Kaunda district in the North-West Province, South Africa; and secondly, to develop a LBEP prediction model from several anthropometric measurements among a cohort of male and female adolescents living in the Tlokwe local municipality of Dr Kenneth Kaunda district in the North-West Province, South Africa. Two hundred and fourteen (15.8±0.68 years) 15-year-old adolescents (126 females, 88 males) from 6 surrounding schools within the Tlokwe local municipality of Dr Kenneth Kaunda district in the North-West Province of South Africa were purposefully selected from pre-acquired class lists took part in the study. Data was collected by means of various questionnaires as well as anthropometrical, physical and motor performance tests. For representation of LBEP a principal component factor analysis was done and the results indicated that the vertical jump test (VJT) was the best indicator of LBEP in the cohort of adolescents. With regard to the anthropometrical related LBEP prediction model, the forward stepwise regression analysis yielded a correlation coefficient of R2 = 0.69. The following variables contributed significantly (p≤0.001) to the anthropometrical LBEP prediction model: stature (57%), muscle mass percentage (10%) and maturity age (3%). The LBEP prediction model that was developed equated to LBEP (vertical jump) = -136.30 + 0.84(stature) + 0.7(muscle mass percentage) + 4.6(maturity age). Variables other than the variables that formed part of the study could explain the further 31% variance in the LBEP of the adolescents. The physical and motor performance LBEP prediction model indicated that gender (39%) and 10 m speed (7%) contributed significantly (p ≤ 0.001) to the overall prediction of the LBEP of the adolescents. The LBEP prediction model delivered a stepwise forward regression analysis coefficient of R2=0.458 and a prediction formula LBEP = 68.21 + 9.82 (gender) – 18.33(10 m speed). The remaining 56% of the variance in the results could be explained by other factors than the variables considered in the study. In conclusion, to the best of the researchers’ knowledge, this is the first study which has made an attempt at developing LBEP prediction models from the anthropometrical, physical and motor performance components of a cohort of adolescents of South Africa. The prediction models developed in the study will assist teachers sport scientists and sporting coaches who have limited resources available, to measure and calculate LBEP in adolescents, with the means to do so in South Africa. Further high quality studies are necessary to further improve and develop such prediction models for various age groups of adolescents in the greater South Africa. / MSc (Sport Science), North-West University, Potchefstroom Campus, 2014

Lower body explosive power (LBEP) forms a critical component in any individual and team sport performance and it is therefore essential to develop a means of predicting LBEP in adolescents for early identification of future talent in various sporting codes. LBEP is frequently used by athletes during matches or competitions where explosive movements such as jumping, agility running and sprinting are required for successful performance. These movements are usually found in individual sports such as long jump and high jump as well as in team sports such as basketball, volleyball and soccer. To date not much literature is available on LBEP, especially with regard to LBEP prediction models. Furthermore, studies on adolescents are scarce and a LBEP prediction model has not yet been developed for a South African adolescent population. It is against this background that the objectives of this study were firstly, to develop a LBEP prediction model from various physical and motor performance components among a cohort of adolescents living in the Tlokwe local municipality of Dr Kenneth Kaunda district in the North-West Province, South Africa; and secondly, to develop a LBEP prediction model from several anthropometric measurements among a cohort of male and female adolescents living in the Tlokwe local municipality of Dr Kenneth Kaunda district in the North-West Province, South Africa. Two hundred and fourteen (15.8±0.68 years) 15-year-old adolescents (126 females, 88 males) from 6 surrounding schools within the Tlokwe local municipality of Dr Kenneth Kaunda district in the North-West Province of South Africa were purposefully selected from pre-acquired class lists took part in the study. Data was collected by means of various questionnaires as well as anthropometrical, physical and motor performance tests. For representation of LBEP a principal component factor analysis was done and the results indicated that the vertical jump test (VJT) was the best indicator of LBEP in the cohort of adolescents. With regard to the anthropometrical related LBEP prediction model, the forward stepwise regression analysis yielded a correlation coefficient of R2 = 0.69. The following variables contributed significantly (p≤0.001) to the anthropometrical LBEP prediction model: stature (57%), muscle mass percentage (10%) and maturity age (3%). The LBEP prediction model that was developed equated to LBEP (vertical jump) = -136.30 + 0.84(stature) + 0.7(muscle mass percentage) + 4.6(maturity age). Variables other than the variables that formed part of the study could explain the further 31% variance in the LBEP of the adolescents. The physical and motor performance LBEP prediction model indicated that gender (39%) and 10 m speed (7%) contributed significantly (p ≤ 0.001) to the overall prediction of the LBEP of the adolescents. The LBEP prediction model delivered a stepwise forward regression analysis coefficient of R2=0.458 and a prediction formula LBEP = 68.21 + 9.82 (gender) – 18.33(10 m speed). The remaining 56% of the variance in the results could be explained by other factors than the variables considered in the study. In conclusion, to the best of the researchers’ knowledge, this is the first study which has made an attempt at developing LBEP prediction models from the anthropometrical, physical and motor performance components of a cohort of adolescents of South Africa. The prediction models developed in the study will assist teachers sport scientists and sporting coaches who have limited resources available, to measure and calculate LBEP in adolescents, with the means to do so in South Africa. Further high quality studies are necessary to further improve and develop such prediction models for various age groups of adolescents in the greater South Africa. / MSc (Sport Science), North-West University, Potchefstroom Campus, 2014

The main goal of this study was to evaluate whether three dimensional musculoskeletal modelling (3D) is effective in assessing the safety and efficacy of resistance training equipment. The focus of the evaluation was on the biomechanical and anthropometric considerations of the end-user. 3D musculoskeletal modelling was used to evaluate four pieces of resistance training equipment, namely the seated biceps curl, abdominal crunch, seated row and chest press. Three anthropometric cases were created; these represented a traditional 5th percentile female as well as a 50th and 95th percentile male based on body mass index (BMI). Resistance on the training machines was set at fifty percent of the functional strength one repetition maximum (1RM), for each anthropometric case and piece of exercise equipment two repetitions were performed except for the abdominal crunch model during which four repetitions were simulated. Each piece of equipment presented unique challenges. In three of the four studies (seated biceps curl, seated row and chest press) the default model created by the modelling software was not adequate to solve the forward dynamics simulations and thus adjustments had to be made to the default model in order to complete the modelling process. 3D musculoskeletal modelling by means of LifeModelerTM software was able to identify some potential risk for musculoskeletal injury as well as highlight the discrepancies between the anthropometric cases, specifically the accommodation of the 5th percentile female and the machines’ engineered adjustability. 3D musculoskeletal modelling has the potential to indicate shortcomings in resistance training equipment design. Therefore it appears as if 3D musculoskeletal modelling can be used to evaluate resistance training equipment design however the limitations as indicated by this study must be taken into consideration especially when using default models.AFRIKAANS: Die doel van die studie was om die effektiwiteit van driedimensionele (3D) muskuloskeletale modellering te evalueer in terme van die tegniek se vermoë om die veiligheid en doeltreffendheid van weerstands oefenapparaat te evalueer. Die fokus van die evaluasie was op die biomeganiese en antropometriese oorwegings van die end-gebruiker. 3D muskuloskeletale modellering was gebruik in die evaluasie van vier weerstands oefenapparate genaamd die sittende biceps krul, abdominale krul, sittende roei en sittende borsstoot. Drie antropometriese gevalle is geskep, die het ‘n tradisionele 5e persentiel vrou, sowel as ‘n 50ste en 95ste persentiel man voorgestel en was gebasseer op liggaamsmassa indeks waardes. Die eksterne weerstand van die apparaat was bepaal teen vyftig persent van die funsionele krag een-repetisie- maksimum vir elk van die antropometriese gevalle en twee repetisies is uitgevoer behalwe vir die abdominale krul waartydens vier repetisies gesimuleer is. Elke apparaat het unieke uitdagings gestel. In drie van die vier studies (sittende biceps krul, sittende roei en sittende borsstoot) was die standaard model van die sagteware onvoldoende om die voorwaards dinamiese simulasie op te los en moes aanpassings aan die modelle gemaak word vir suksesvolle simulasies. Die modellerings proses met die Lifemodeler™ sagteware kon potensiële risiko vir muskuloskeletale besering sowel as verskille tussen die verskeie antropometriese gevalle uitwys. Dit was veral opvallend vir die akkomodasie van die 5e persentiel vrou asook betreffende die apparaat se vervaardigde verstelbaarheid. 3D muskuloskeletale modellering beskik oor die vermoë om voorstelle vir verbetering in die ontwerp van weerstands oefenapparaat uit te wys. Dit blyk dus dat 3D muskuloskeletale modellering beslis gebruik kan word vir die evaluasie van weerstands oefenapparaat ontwerp, die beperkings van die studie moet egter in gedagte gehou word, veral wanneer standaard modelle gebruik word. / Thesis (DPhil)--University of Pretoria, 2011. / Biokinetics, Sport and Leisure Sciences / unrestricted