Comparison of offensive agility techniques in Australian Rules football
- Authors: Bradshaw, Ryan , Young, Warren , Russell, Andrew , Burge, Peter
- Date: 2011
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 14, no. 1 (2011), p. 65-69
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- Description: Agility skill is important in Australian Rules football (ARF) as it enables an attacking player to successfully evade an opponent. To date, no research has examined offensive agility techniques in ARF. There were two purposes of this study: first, to compare the change of direction (COD) speed of three offensive agility techniques, and second, compare the reaction speed and accuracy when observing the same techniques from a defensive perspective. The techniques included the side-step, shuffle, and split-step. Seventeen players from an Australian Football League club were required to perform four trials of each technique. COD speed was expressed as a total time, and divided into entry, foot plant preparation, and exit time. In addition, nineteen players from the same club were assessed on a video-based reaction test. Players were required to respond by depressing a thumb switch to indicate whether the player on screen changed direction to the left or right. From an offensive perspective, the split-step foot plant preparation time (0.66. s) was significantly slower than both the side-step (0.7 s) and shuffle (0.75 s) (p< 0.05), but there were no significant differences in entry and exit times between techniques. From a defensive perspective, the players were significantly slower and less accurate when reacting to the player in the video performing the split-step (0.19. s) and shuffle (0.15. s) compared to the side-step (0.12 s) (p< 0.05). In a one-on-one situation in ARF, the split-step may be the most effective offensive technique. Not only was it slower and less accurate to react to, the exit speed following the change in direction was not significantly slower than the side-step. However, a performer would need to consider the cost of a slower foot plant preparation time versus the potential to deceive an opponent when under time stress. © 2010 Sports Medicine Australia.
Measuring children's self-reported sport participation, risk perception and injury history : Development and validation of a survey instrument
- Authors: Siesmaa, Emma , Blitvich, Jennifer , White, Peta , Finch, Caroline
- Date: 2011
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 14, no. 1 (2011), p. 22-26
- Relation: http://purl.org/au-research/grants/nhmrc/565900
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- Description: Despite the health benefits associated with children's sport participation, the occurrence of injury in this context is common. The extent to which sport injuries impact children's ongoing involvement in sport is largely unknown. Surveys have been shown to be useful for collecting children's injury and sport participation data; however, there are currently no published instruments which investigate the impact of injury on children's sport participation. This study describes the processes undertaken to assess the validity of two survey instruments for collecting self-reported information about child cricket and netball related participation, injury history and injury risk perceptions, as well as the reliability of the cricket-specific version. Face and content validity were assessed through expert feedback from primary and secondary level teachers and from representatives of peak sporting bodies for cricket and netball. Test-retest reliability was measured using a sample of 59 child cricketers who completed the survey on two occasions, 3-4 weeks apart. Based on expert feedback relating to face and content validity, modification and/or deletion of some survey items was undertaken. Survey items with low test-retest reliability (κ≤ 0.40) were modified or deleted, items with moderate reliability (κ=0.41-0.60) were modified slightly and items with higher reliability (κ≥ 0.61) were retained, with some undergoing minor modifications. This is the first survey of its kind which has been successfully administered to cricketers aged 10-16 years to collect information about injury risk perceptions and intentions for continued sport participation. Implications for its generalisation to other child sport participants are discussed. © 2010 Sports Medicine Australia.
The relationship between physical capacity and match performance in elite Australian football : A mediation approach
- Authors: Mooney, Mitchell , O'Brien, Brendan , Cormack, Stuart , Coutts, Aaron , Berry, Jason , Young, Warren
- Date: 2011
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 14, no. 5 (2011), p. 447-452
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- Description: The aim of this study was to verify if yo-yo intermittent recovery test (level 2) (yo-yo IR2) score is linked to Australian football (AF) performance through match exercise intensity. Six week prospective study design. Twenty-one data sets were recorded from nine individual players that completed the yo-yo IR2, and played an Australian Football League match in the first five rounds of the 2010 season wearing a global positioning system (GPS) unit. Simple mediation modelling was used to analyse the inter-relationship between yo-yo IR2 score, match exercise intensity and AF performance. Playing position and experience were also incorporated into the model to identify conditional affects. A significant direct relationship was observed between yo-yo IR2 and number of ball disposals (p<0.1) and a significant indirect relationship was observed between yo-yo IR2 and number of ball disposals through distance travelled at high intensity (HIR mmin-1) (p<0.1). Moderation analysis showed that playing position affected the relationship between of yo-yo IR2 and HIR mmin-1 (p<0.1) and HIR mmin-1 and total ball disposals (p<0.1). Playing experience also significantly affected the relationship between HIR mmin-1 and total ball disposals. This study is the first to identify the effects of yo-yo IR2 on total ball disposals through HIR mmin-1 performed during AF matches, and that playing position and playing experience affect these interactions. © 2011 Sports Medicine Australia.
Greater understanding of normal hip physical function may guide clinicians in providing targeted rehabilitation programmes
- Authors: Kemp, Joanne , Schache, Anthony , Makdissi, Michael , Sims, Kevin , Crossley, Kay
- Date: 2013
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 16, no. 4 (2013), p. 292-296
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- Description: Objectives: This study investigated tests of hip muscle strength and functional performance. The specific objectives were to: (i) establish intra- and inter-rater reliability; (ii) compare differences between dominant and non-dominant limbs; (iii) compare agonist and antagonist muscle strength ratios; (iv) compare differences between genders; and (v) examine relationships between hip muscle strength, baseline measures and functional performance. Design: Reliability study and cross-sectional analysis of hip strength and functional performance. Methods: In healthy adults aged 18-50. years, normalised hip muscle peak torque and functional performance were evaluated to: (i) establish intra-rater and inter-rater reliability; (ii) analyse differences between limbs, between antagonistic muscle groups and genders; and (iii) associations between strength and functional performance. Results: Excellent reliability (intra-rater ICC = 0.77-0.96; inter-rater ICC = 0.82-0.95) was observed. No difference existed between dominant and non-dominant limbs. Differences in strength existed between antagonistic pairs of muscles: hip abduction was greater than adduction (p < 0.001) and hip ER was greater than IR (p < 0.001). Men had greater ER strength (p = 0.006) and hop for distance (p < 0.001) than women. Strong associations were observed between measures of hip muscle strength (except hip flexion) and age, height, and functional performance. Conclusions: Deficits in hip muscle strength or functional performance may influence hip pain. In order to provide targeted rehabilitation programmes to address patient-specific impairments, and determine when individuals are ready to return to physical activity, clinicians are increasingly utilising tests of hip strength and functional performance. This study provides a battery of reliable, clinically applicable tests which can be used for these purposes. © 2012 Sports Medicine Australia.