Stress fractures represent one of the most common and serious overuse injuries in the military environment. The aim of this prospective study was to determine the incidence of stress fractures during 12 weeks of Basic Training (BT) by comparing the results of the intrinsic risk indicators obtained from a group of participants who suffered stress fractures, with the rest of the original group (controls) who did not suffer from any stress fractures, and to assess any changes in physical markers whilst following a progressive, scientifically designed, Physical Training (PT) Programme during the BT. The intrinsic risk factors investigated included sex, age, race (measured via questionnaire), foot morphology (wet test), Q angle, leg length discrepancy, bone density (dual-energy X-ray absorptiometry(DEXA), physical fitness (standardized military fitness test, isokinetic upper and lower leg strength, handgrip strength), flexibility (ankle plantarflexion and dorsiflexion, hip internal and external rotation), anthropometry (skinfold method and DEXA), female menstrual disturbances and lifestyle behaviours including smoking, female contraception use and medical history of previous injury (questionnaire). The cohort (n=183), also refered to as the Experimental Group (EG), was measured at the beginning and at the end of the BT period. The standardized physical fitness test was also completed in the fifth week of training. The latter’s results were compared to the results obtained by a Control Group (CG), who had undergone BT the year prior to this cohort. The size of the cohort, the intrinsic risk factor profile and the control of certain extrinsic risk factors may have contributed to zero incidences of stress fractures found. Within the intrinsic risk factor profile, sex, age, race, foot morphology, Q angle, hip external rotation and bone density were normal whilst the measured leg discrepancy and limited ankle dorsiflexion appeared to not have a sufficient risk for stress fracture development. The small sample of the cohort that reported having menstrual irregularities, smoked and had a history of previous fractures, did not place this cohort at risk for stress fracture development. The cohort did, however have lower isotonic, isokinetic and isometric strengths than the other cohorts who reported a relatively high stress fracture incidence. The BT period found statistically significant changes in bone density, flexibility, body composition, muscle strength and endurance. Female participants showed an increase in the T- and Z-scores of the left femur area, a deterioration in left ankle dorsiflexion and hip external rotation, whilst their plantarflexion increased. Their mesomorph component increased, and decreases in % body fat (BF) as well as in the ectomorph and endomorph component were also found. Male participants’ plantarflexion and hip external rotation decreased whilst their dorsiflexion increased. Lean body mass and mesomorph component increased whilst %BF, ectomorph and endomorph component decreased. The new cyclic-progressive PT programme controlled for risk of injury by allowing sufficient periods of recovery, by gradually increasing the duration, frequency, and intensity of training, by reducing repetitive weight-bearing activities and by including a variation of exercises. Running shoes, rather than combat boots, were also worn during PT. Marching on concrete was eliminated. Significant improvements were shown by both male and female participants in aerobic fitness and muscular endurance and muscular strength. Future research should include a larger size cohort, who developed stress fractures utilising BT groups from different corps and units in the South African Military environment. Other potential extrinsic risk factors, such as surface and equipment, should also be investigated. / Thesis (DPhil)--University of Pretoria, 2009. / Biokinetics, Sport and Leisure Sciences / unrestricted

Background: The incidence of injuries in rugby union has increased on both professional and amateur levels since the introduction of professionalism in 1995. Although rugby union is a body contact sport with an expected high injury rate, limited research has been done regarding the postural and biomechanical characteristics of the players and the effect these variables have on the incidence and nature of rugby union injuries. Large body size is a significant predictor of success in rugby union and the body mass and mesomorphy of players has increased over the last years. It has, however, not been thoroughly investigated whether changes in body composition have any effect on the incidence of rugby union injuries. Intrinsic risk factors that have been identified to contribute to rugby union injuries are Hyper-mobility of joints, lack of dynamic mobility and core stability, previous injuries, aerobic and anaerobic fitness as well as the personalities and characteristics of players which affect their on-field awareness. The findings of studies investigating the relation between player characteristics and rugby union injuries are inconsistent because of the differences in player characteristics under investigation and playing conditions, different research methodologies used as well as differences in the way injury is defined. Therefore, the need exists to determine the differences in the biomechanical, postural and anthropometrical characteristics of injured and uninjured rugby union players by making use of a prospective design and a standardized injury definition. Objectives: The objectives of this study were firstly, to determine the incidence and nature of injuries among U/21 rugby union players at the Rugby Institute (RI) of the North-West University (NWU) (South Africa) and secondly, to determine which of the selected biomechanical, postural and anthropometrical characteristics contributed to musculoskeletal injuries obtained during the first five months of the 2005 season. Method: s A prospective once-off subject availability study was performed that included forty-nine U/21-rugby union players of the RI of the NWU. Biomechanical, postural and anthropometrical assessments were performed on all subjects before the start of the 2005- season. All the injuries sustained during the first five months of the 2005 season were recorded by means of a validated rugby union injury report questionnaire. A stepwise discriminant analysis identified the independent variables that discriminated mostly between the players with and without injuries within the different body regions. Back-classification by means of the "Jack-knife method" determined whether the independent characteristics that were selected to contribute to injuries was valid and the effect size, I ("better than chance"), was then determined, with I > 0.3 accepted as practically significant. Results: A total of 66 injuries with an injury rate of 8.611000 training hours and 61.811000 game hours were reported. Severe injuries accounted for 53% of all injuries to forward players with the ankle being the most injured anatomical region. In the backline severe injuries accounted for 11% with the shoulder being the most injured region. The tackle was the phase of play in which most injuries occurred. The statistical analysis identified uneven hips, pronated feet, tight hamstrings, anatomical leg length differences, gait pronation and a tall stature to be practically significant predictors for lower extremity injuries (I>0.3). No practical significance was obtained for the selected biomechanical, postural and anthropometrical characteristics related to shoulder girdle as well as back or spine injuries. Conclusions: The conclusions that can be drawn from this study are that the injury incidence of rugby union players of the U/21-squad of the RI of the NWU is high in comparison with those of other club level players and that postural and biomechanical imbalances of the lower extremities may increase the risk for injury in this area. / Thesis (M.A. (Human Movement Science))--North-West University, Potchefstroom Campus, 2007.

Background: The incidence of injuries in rugby union has increased on both professional and amateur levels since the introduction of professionalism in 1995. Although rugby union is a body contact sport with an expected high injury rate, limited research has been done regarding the postural and biomechanical characteristics of the players and the effect these variables have on the incidence and nature of rugby union injuries. Large body size is a significant predictor of success in rugby union and the body mass and mesomorphy of players has increased over the last years. It has, however, not been thoroughly investigated whether changes in body composition have any effect on the incidence of rugby union injuries. Intrinsic risk factors that have been identified to contribute to rugby union injuries are Hyper-mobility of joints, lack of dynamic mobility and core stability, previous injuries, aerobic and anaerobic fitness as well as the personalities and characteristics of players which affect their on-field awareness. The findings of studies investigating the relation between player characteristics and rugby union injuries are inconsistent because of the differences in player characteristics under investigation and playing conditions, different research methodologies used as well as differences in the way injury is defined. Therefore, the need exists to determine the differences in the biomechanical, postural and anthropometrical characteristics of injured and uninjured rugby union players by making use of a prospective design and a standardized injury definition. Objectives: The objectives of this study were firstly, to determine the incidence and nature of injuries among U/21 rugby union players at the Rugby Institute (RI) of the North-West University (NWU) (South Africa) and secondly, to determine which of the selected biomechanical, postural and anthropometrical characteristics contributed to musculoskeletal injuries obtained during the first five months of the 2005 season. Method: s A prospective once-off subject availability study was performed that included forty-nine U/21-rugby union players of the RI of the NWU. Biomechanical, postural and anthropometrical assessments were performed on all subjects before the start of the 2005- season. All the injuries sustained during the first five months of the 2005 season were recorded by means of a validated rugby union injury report questionnaire. A stepwise discriminant analysis identified the independent variables that discriminated mostly between the players with and without injuries within the different body regions. Back-classification by means of the "Jack-knife method" determined whether the independent characteristics that were selected to contribute to injuries was valid and the effect size, I ("better than chance"), was then determined, with I > 0.3 accepted as practically significant. Results: A total of 66 injuries with an injury rate of 8.611000 training hours and 61.811000 game hours were reported. Severe injuries accounted for 53% of all injuries to forward players with the ankle being the most injured anatomical region. In the backline severe injuries accounted for 11% with the shoulder being the most injured region. The tackle was the phase of play in which most injuries occurred. The statistical analysis identified uneven hips, pronated feet, tight hamstrings, anatomical leg length differences, gait pronation and a tall stature to be practically significant predictors for lower extremity injuries (I>0.3). No practical significance was obtained for the selected biomechanical, postural and anthropometrical characteristics related to shoulder girdle as well as back or spine injuries. Conclusions: The conclusions that can be drawn from this study are that the injury incidence of rugby union players of the U/21-squad of the RI of the NWU is high in comparison with those of other club level players and that postural and biomechanical imbalances of the lower extremities may increase the risk for injury in this area. / Thesis (M.A. (Human Movement Science))--North-West University, Potchefstroom Campus, 2007.