title: The effects of heavy-sled sprint training on acceleration capabilities in female rugby sevens athletes: A pilot study

authors: Sella, Francesco Stefano

abstract: INTRODUCTION: Well-developed acceleration abilities are critical for performance in rugby sevens. In this pilot study, we investigated the effects of heavy-sled sprint training on acceleration in female rugby sevens athletes. METHODS: Eleven junior female rugby sevens athletes completed 3-weeks of resisted sprint training (5-30 m) with heavy sleds (30 to 85% of body mass). Acceleration performance and biomechanical outputs were computed pre- and post-intervention using the methods described by Samozino et al. (2016). Training-induced changes were calculated using effect size (ES) and magnitude-based inferences. Correlations (r) between changes in sprint performance and biomechanical outputs (pre-post changes, and at baseline) were calculated. RESULTS: Small improvements in 5 m and 10 m times, and changes in mechanical effectiveness of force application (RFmax), maximum power output (Pmax), and force-velocity slope (SFV) were observed (ES = 0.36-0.40). Very large to almost perfect correlations were found between changes in 5 m and 10 m times with changes in Pmax, theoretical maximal (horizontal) force (F0), RFmax, rate of decrease in mechanical effectiveness (DRF), and SFV (r = 0.85-0.96). Changes in 5 m and 10m times were also very largely to almost perfectly correlated with initial individual profiles (SFV, DRF, F0, and Pmax) (r = 0.73-0.91). DISCUSSION: Heavy-sled sprint training was likely to improve 5 m and 10 m times, maximum power, and sprint biomechanics. Changes in Pmax, F0, DRF, RFmax, and SFV explained over 72% of the variance associated with improvements in 5 m and 10 m times. Furthermore, retrospective analysis showed that the initial individual force-velocity profiles were associated with the magnitude of improvements in sprint characteristics. TAKE HOME MESSAGE: Heavy-sled sprint training is likely to increase acceleration capabilities over short distances in female rugby sevens athletes. Changes in defined biomechanical outputs, and individual force-velocity profiles appear to be associated with these improvements.

text: The effects of heavy-sled sprint training on acceleration capabilities in female rugby sevens athletes: A pilot study INTRODUCTION: Well-developed acceleration abilities are critical for performance in rugby sevens. In this pilot study, we investigated the effects of heavy-sled sprint training on acceleration in female rugby sevens athletes. METHODS: Eleven junior female rugby sevens athletes completed 3-weeks of resisted sprint training (5-30 m) with heavy sleds (30 to 85% of body mass). Acceleration performance and biomechanical outputs were computed pre- and post-intervention using the methods described by Samozino et al. (2016). Training-induced changes were calculated using effect size (ES) and magnitude-based inferences. Correlations (r) between changes in sprint performance and biomechanical outputs (pre-post changes, and at baseline) were calculated. RESULTS: Small improvements in 5 m and 10 m times, and changes in mechanical effectiveness of force application (RFmax), maximum power output (Pmax), and force-velocity slope (SFV) were observed (ES = 0.36-0.40). Very large to almost perfect correlations were found between changes in 5 m and 10 m times with changes in Pmax, theoretical maximal (horizontal) force (F0), RFmax, rate of decrease in mechanical effectiveness (DRF), and SFV (r = 0.85-0.96). Changes in 5 m and 10m times were also very largely to almost perfectly correlated with initial individual profiles (SFV, DRF, F0, and Pmax) (r = 0.73-0.91). DISCUSSION: Heavy-sled sprint training was likely to improve 5 m and 10 m times, maximum power, and sprint biomechanics. Changes in Pmax, F0, DRF, RFmax, and SFV explained over 72% of the variance associated with improvements in 5 m and 10 m times. Furthermore, retrospective analysis showed that the initial individual force-velocity profiles were associated with the magnitude of improvements in sprint characteristics. TAKE HOME MESSAGE: Heavy-sled sprint training is likely to increase acceleration capabilities over short distances in female rugby sevens athletes. Changes in defined biomechanical outputs, and individual force-velocity profiles appear to be associated with these improvements.

year: 2018

title: The MG retrieval system: compressing for space and speed

authors: Bell, Timothy C.

subjects: computer science

abstract: Recent advances in compression and indexing techniques have yielded a qualitative change in the feasibility of large-scale full-text retrieval.

text: The MG retrieval system: compressing for space and speed Recent advances in compression and indexing techniques have yielded a qualitative change in the feasibility of large-scale full-text retrieval.

year: 1995

title: Youth Development Circles: A Report on a School Trial

authors: Hannah, Belinda Anne

subjects: Youth Development Circles

abstract: This research traces the development and trial of the Youth Development Circle (YDC) process in a low decile secondary school in a rural community in Aotearoa New Zealand. Youth Development Circles are an intervention based on restorative justice principles initially proposed by Braithwaite (2004). They were originally suggested as a strategy for use in an alternative education centre or “activity centre”.  Increasing use of restorative approaches has enabled many schools to make significant progress in reducing suspensions, but there remains a concern for students whose behaviour is at the more serious end of the spectrum - who are at risk of suspension, or exclusion, after multiple stand-downs from school.  The possibilities for the use of YDC were proposed to the school by the researcher, who is a Deputy Principal responsible for behaviour management and pastoral care.  This proposal was supported fully by the school’s staff and Board of Trustees.  The YDC process documented in this study was developed by the researcher, informed by a range of sources including Youth Development Circles, Judge McElrea’s proposed School Community Conference (1996), and Hui Whakatika, developed at the University of Waikato (2003).  Participation in the circles was a condition for the student to remain at the school. The school is a state school, with a roll of approximately 800. The ethnic breakdown of the students is 56% Māori and 39% NZ European with 5% of Pasifika, Asian and other.  

The YDC is a deliberate and careful process which aims to bring increased focus on the individual student and their educational outcomes, through engaging a community of care in supporting them. There were many anticipated benefits of the YDC for the student. Such benefits included an opportunity to establish and maintain healthy relationships of trust (within which negative experiences can be learned from), a re-establishment of trust, improved self-confidence and improved educational outcomes. The circles included members of the student’s whānau/family, a kaumātua/elder who cared about them, and representatives from local Police, Social Welfare, and the school.  The circles were studied over a period of one year.  Circles met regularly throughout this time, at increasing intervals.

A mixed method case study approach was used for this research which includes the collection of both quantitative and qualitative data. The study evaluated the effectiveness of the YDCs by analysing student behaviour, attendance and achievement KAMAR data, minutes of each circle meeting, and interviews with circle participants.


Three student case studies are presented.  The stories have had details altered and pseudonyms used to protect the persons involved. All the students completed the academic year without receiving a further stand down or suspension.  The data showed an improvement in student attendance, achievement and engagement in all three case studies.  Other outcomes include reflections on the process used, strategies for implementation in the school, and factors that either hindered or supported student, family or community involvement in YDCs. 

This exploratory study suggests that the Youth Development Circle could offer a unique possibility for inter-sectorial collaboration in the field of restorative justice.

text: Youth Development Circles: A Report on a School Trial This research traces the development and trial of the Youth Development Circle (YDC) process in a low decile secondary school in a rural community in Aotearoa New Zealand. Youth Development Circles are an intervention based on restorative justice principles initially proposed by Braithwaite (2004). They were originally suggested as a strategy for use in an alternative education centre or “activity centre”.  Increasing use of restorative approaches has enabled many schools to make significant progress in reducing suspensions, but there remains a concern for students whose behaviour is at the more serious end of the spectrum - who are at risk of suspension, or exclusion, after multiple stand-downs from school.  The possibilities for the use of YDC were proposed to the school by the researcher, who is a Deputy Principal responsible for behaviour management and pastoral care.  This proposal was supported fully by the school’s staff and Board of Trustees.  The YDC process documented in this study was developed by the researcher, informed by a range of sources including Youth Development Circles, Judge McElrea’s proposed School Community Conference (1996), and Hui Whakatika, developed at the University of Waikato (2003).  Participation in the circles was a condition for the student to remain at the school. The school is a state school, with a roll of approximately 800. The ethnic breakdown of the students is 56% Māori and 39% NZ European with 5% of Pasifika, Asian and other.  

The YDC is a deliberate and careful process which aims to bring increased focus on the individual student and their educational outcomes, through engaging a community of care in supporting them. There were many anticipated benefits of the YDC for the student. Such benefits included an opportunity to establish and maintain healthy relationships of trust (within which negative experiences can be learned from), a re-establishment of trust, improved self-confidence and improved educational outcomes. The circles included members of the student’s whānau/family, a kaumātua/elder who cared about them, and representatives from local Police, Social Welfare, and the school.  The circles were studied over a period of one year.  Circles met regularly throughout this time, at increasing intervals.

A mixed method case study approach was used for this research which includes the collection of both quantitative and qualitative data. The study evaluated the effectiveness of the YDCs by analysing student behaviour, attendance and achievement KAMAR data, minutes of each circle meeting, and interviews with circle participants.


Three student case studies are presented.  The stories have had details altered and pseudonyms used to protect the persons involved. All the students completed the academic year without receiving a further stand down or suspension.  The data showed an improvement in student attendance, achievement and engagement in all three case studies.  Other outcomes include reflections on the process used, strategies for implementation in the school, and factors that either hindered or supported student, family or community involvement in YDCs. 

This exploratory study suggests that the Youth Development Circle could offer a unique possibility for inter-sectorial collaboration in the field of restorative justice.

year: 2015