title: Establishing normative calf muscle function values in male rugby union athletes in New Zealand

authors: Ngawhika, Te Manawa

subjects: Biomechanics

abstract: Rugby union is a popular and fast-growing sport played internationally that involves high levels of physical contact and running activities. Unfortunately, these physical requirements can often lead to soft-tissue injuries. Some of the most common injuries resulting from rugby union occur to the triceps surae muscle-tendon unit (MTU). The calf raise test is one of the most commonly used tests in clinical practice to assess triceps surae muscle function, especially endurance. Clinicians and researchers have also used variations of this test in the assessment and management of individuals with Achilles tendinopathies or Achilles tendon ruptures, such as  eccentric-concentric power tests. These data, however, generally derive from general or injured populations. To date, limited research has assessed triceps surae muscle function in rugby union athletes. Chapter One explores literature focusing on the triceps surae MTU (anatomy and injuries), rugby union, rugby-related injuries, and calf muscle testing procedures, specifically the calf raise test and eccentric-concentric power tests. Chapter Two aims to establish normative calf muscle function values in uninjured male rugby union athletes, examine the test-retest reliability of key measures across repeated testing sessions, and assess the validity of clinical testing methods using a novel Calf Raise application against research-grade laboratory equipment. Finally, Chapter Three summarises and discusses the key findings, limitations, and strengths of the experimental chapter, and addresses potential future research directions.

In Chapter Two, 120 rugby union athletes participated in establishing normative calf muscle function values, and were categorised into playing position (forwards and backs) and level of professionalism (International, Super Rugby, Provincial, and Club), while also considering age, leg dominance, body mass index (BMI), and previous MTU injuries. Eighteen athletes participated in test-retest reliability and performed an additional two testing sessions 1 week apart, whereas 20 athletes participated in validation of the Calf Raise application outcomes. All participants completed three calf muscle tests: 1) eccentric-concentric bodyweight power test; 2) eccentric-concentric weighted power test; and 3) concentric-eccentric endurance test. Reliability was acceptable across outcomes following familiarisation (coefficient of variation < 10%, intraclass correlation ≥ 0.83). Validity of the application outcomes against 3D motion capture and force plate data was also acceptable (coefficient of variation ≤ 6.6%, intraclass correlation ≥ 0.84). Forwards produced superior power during the bodyweight (59 W, p = 0.007) and weighted (73 W, p < 0.001) power tests, with playing level significantly influencing outcomes (p < 0.009). Super Rugby players were more powerful than Club and Provincial players in both power tests, and International in the bodyweight test. Backs completed more repetitions (3 repetitions, p = 0.001) and positive displacement (30 cm, p = 0.001) than forwards during endurance testing, with no influence of level. When accounting for the clinically relevant factors, BMI, age, and previous injury explained some of the differences observed between positions and levels. These findings support previous research highlighting differences in rugby union athletes based on position and level, and provide initial benchmark values of calf muscle function for rugby union players in New Zealand. Given the results stem from uninjured male rugby union athletes, results cannot be generalised to females, different rugby codes, and those with a current or rehabilitating MTU injury.

text: Establishing normative calf muscle function values in male rugby union athletes in New Zealand Rugby union is a popular and fast-growing sport played internationally that involves high levels of physical contact and running activities. Unfortunately, these physical requirements can often lead to soft-tissue injuries. Some of the most common injuries resulting from rugby union occur to the triceps surae muscle-tendon unit (MTU). The calf raise test is one of the most commonly used tests in clinical practice to assess triceps surae muscle function, especially endurance. Clinicians and researchers have also used variations of this test in the assessment and management of individuals with Achilles tendinopathies or Achilles tendon ruptures, such as  eccentric-concentric power tests. These data, however, generally derive from general or injured populations. To date, limited research has assessed triceps surae muscle function in rugby union athletes. Chapter One explores literature focusing on the triceps surae MTU (anatomy and injuries), rugby union, rugby-related injuries, and calf muscle testing procedures, specifically the calf raise test and eccentric-concentric power tests. Chapter Two aims to establish normative calf muscle function values in uninjured male rugby union athletes, examine the test-retest reliability of key measures across repeated testing sessions, and assess the validity of clinical testing methods using a novel Calf Raise application against research-grade laboratory equipment. Finally, Chapter Three summarises and discusses the key findings, limitations, and strengths of the experimental chapter, and addresses potential future research directions.

In Chapter Two, 120 rugby union athletes participated in establishing normative calf muscle function values, and were categorised into playing position (forwards and backs) and level of professionalism (International, Super Rugby, Provincial, and Club), while also considering age, leg dominance, body mass index (BMI), and previous MTU injuries. Eighteen athletes participated in test-retest reliability and performed an additional two testing sessions 1 week apart, whereas 20 athletes participated in validation of the Calf Raise application outcomes. All participants completed three calf muscle tests: 1) eccentric-concentric bodyweight power test; 2) eccentric-concentric weighted power test; and 3) concentric-eccentric endurance test. Reliability was acceptable across outcomes following familiarisation (coefficient of variation < 10%, intraclass correlation ≥ 0.83). Validity of the application outcomes against 3D motion capture and force plate data was also acceptable (coefficient of variation ≤ 6.6%, intraclass correlation ≥ 0.84). Forwards produced superior power during the bodyweight (59 W, p = 0.007) and weighted (73 W, p < 0.001) power tests, with playing level significantly influencing outcomes (p < 0.009). Super Rugby players were more powerful than Club and Provincial players in both power tests, and International in the bodyweight test. Backs completed more repetitions (3 repetitions, p = 0.001) and positive displacement (30 cm, p = 0.001) than forwards during endurance testing, with no influence of level. When accounting for the clinically relevant factors, BMI, age, and previous injury explained some of the differences observed between positions and levels. These findings support previous research highlighting differences in rugby union athletes based on position and level, and provide initial benchmark values of calf muscle function for rugby union players in New Zealand. Given the results stem from uninjured male rugby union athletes, results cannot be generalised to females, different rugby codes, and those with a current or rehabilitating MTU injury.

year: 2021

title: Generating accurate rule sets without global optimization

authors: Frank, Eibe

subjects: computer science

abstract: The two dominant schemes for rule-learning, C4.5 and RIPPER, both operate in two stages. First they induce an initial rule set and then they refine it using a rather complex optimization stage that discards (C4.5) or adjusts (RIPPER) individual rules to make them work better together. In contrast, this paper shows how good rule sets can be learned one rule at a time, without any need for global optimization. We present an algorithm for inferring rules by repeatedly generating partial decision trees, thus combining the two major paradigms for rule generation-creating rules from decision trees and the separate-and-conquer rule-learning technique. The algorithm is straightforward and elegant: despite this, experiments on standard datasets show that it produces rule sets that are as accurate as and of similar size to those generated by C4.5, and more accurate than RIPPER’s. Moreover, it operates efficiently, and because it avoids postprocessing, does not suffer the extremely slow performance on pathological example sets for which the C4.5 method has been criticized.

text: Generating accurate rule sets without global optimization The two dominant schemes for rule-learning, C4.5 and RIPPER, both operate in two stages. First they induce an initial rule set and then they refine it using a rather complex optimization stage that discards (C4.5) or adjusts (RIPPER) individual rules to make them work better together. In contrast, this paper shows how good rule sets can be learned one rule at a time, without any need for global optimization. We present an algorithm for inferring rules by repeatedly generating partial decision trees, thus combining the two major paradigms for rule generation-creating rules from decision trees and the separate-and-conquer rule-learning technique. The algorithm is straightforward and elegant: despite this, experiments on standard datasets show that it produces rule sets that are as accurate as and of similar size to those generated by C4.5, and more accurate than RIPPER’s. Moreover, it operates efficiently, and because it avoids postprocessing, does not suffer the extremely slow performance on pathological example sets for which the C4.5 method has been criticized.

year: 1998-01

title: Ungentlemanly warfare: The impact of irregular warfare on military strategy in the New Zealand Wars

authors: Foy, Rhys

subjects: New Zealand Wars

abstract: ‘Ungentlemanly Warfare’ examines the impact of irregular warfare on strategic thinking in the New Zealand Wars (1845–1872). Britain entered the period as an eighteenth-century force reliant on European methods of war. In contrast, Māori were an experienced bushfighting force depleted on manpower but experiencing a period of military innovation. This interaction led to an important exchange of strategic ideology and methods.  
This thesis tracks how Māori, British, and colonial forces developed and exchanged irregular warfare practices across three regions and time periods. The Northern War exposed the shortcomings of conventional military conduct. Māori leadership altered their strategic approach and pursued a strategy of elastic offence. In contrast, British leadership persisted with their ineffective conventional means of warfare. In the Waikato War, British strategy was influenced by the success of colonial irregulars. British strategic and operational methods changed with the inclusion of multi-echelon warfare and the indirect approach. Kīngitanga leadership improved their combat capacity through guerrilla warfare, decentralised command, and a grand strategy of elastic offence. The Taranaki and West Coast campaigns highlighted the relationship between the use of irregular warfare and military success in New Zealand. Both sides experienced success and failure across numerous conflicts, the defining factor being the active use of irregular warfare. These case studies reveal the significance of irregular warfare strategies and tactics to military success in colonial New Zealand. They also reveal opportunities and challenges to military adaptation in Māori, British, and colonial martial cultures of the nineteenth century. 
 ‘Ungentlemanly Warfare’ provides a unique approach to the examination of the New Zealand Wars conflict. It is an operational history that draws upon methods and aspects of the ‘war and society’ approach to military history, especially the use of Māori scholarship, evidence, and theory. The thesis’ chapters consider strategic and tactical decision-making across the numerous conflicts within the period. To do so, I provide close readings of primary evidence, including military communication and reports, early histories, and first-person accounts, to identify the roles of irregular warfare and strategic adaptions in the New Zealand Wars. 
	‘Ungentlemanly Warfare’ analyses the impact of irregular warfare on the strategic thinking of military leaders within the New Zealand Wars. I argue that irregular warfare strategies and tactics played a significantly larger role in the outcome of events than previously acknowledged. This study illustrates the importance of guerrilla warfare and the strategy of elastic offence to Māori strategy. In contrast, it highlights the evolution of British military thinking from conventional conservatism to a multi-echelon force led by irregular warfare units and tactics. ‘Ungentlemanly Warfare’ argues that irregular warfare was central to military conflicts in nineteenth-century New Zealand.

text: Ungentlemanly warfare: The impact of irregular warfare on military strategy in the New Zealand Wars ‘Ungentlemanly Warfare’ examines the impact of irregular warfare on strategic thinking in the New Zealand Wars (1845–1872). Britain entered the period as an eighteenth-century force reliant on European methods of war. In contrast, Māori were an experienced bushfighting force depleted on manpower but experiencing a period of military innovation. This interaction led to an important exchange of strategic ideology and methods.  
This thesis tracks how Māori, British, and colonial forces developed and exchanged irregular warfare practices across three regions and time periods. The Northern War exposed the shortcomings of conventional military conduct. Māori leadership altered their strategic approach and pursued a strategy of elastic offence. In contrast, British leadership persisted with their ineffective conventional means of warfare. In the Waikato War, British strategy was influenced by the success of colonial irregulars. British strategic and operational methods changed with the inclusion of multi-echelon warfare and the indirect approach. Kīngitanga leadership improved their combat capacity through guerrilla warfare, decentralised command, and a grand strategy of elastic offence. The Taranaki and West Coast campaigns highlighted the relationship between the use of irregular warfare and military success in New Zealand. Both sides experienced success and failure across numerous conflicts, the defining factor being the active use of irregular warfare. These case studies reveal the significance of irregular warfare strategies and tactics to military success in colonial New Zealand. They also reveal opportunities and challenges to military adaptation in Māori, British, and colonial martial cultures of the nineteenth century. 
 ‘Ungentlemanly Warfare’ provides a unique approach to the examination of the New Zealand Wars conflict. It is an operational history that draws upon methods and aspects of the ‘war and society’ approach to military history, especially the use of Māori scholarship, evidence, and theory. The thesis’ chapters consider strategic and tactical decision-making across the numerous conflicts within the period. To do so, I provide close readings of primary evidence, including military communication and reports, early histories, and first-person accounts, to identify the roles of irregular warfare and strategic adaptions in the New Zealand Wars. 
	‘Ungentlemanly Warfare’ analyses the impact of irregular warfare on the strategic thinking of military leaders within the New Zealand Wars. I argue that irregular warfare strategies and tactics played a significantly larger role in the outcome of events than previously acknowledged. This study illustrates the importance of guerrilla warfare and the strategy of elastic offence to Māori strategy. In contrast, it highlights the evolution of British military thinking from conventional conservatism to a multi-echelon force led by irregular warfare units and tactics. ‘Ungentlemanly Warfare’ argues that irregular warfare was central to military conflicts in nineteenth-century New Zealand.

year: 2023