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    Wireless and tiredness : investigating interrelated influences of electronic media use, sleep, and fatigue : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Clinical Psychology at Massey University, Pukeahu, Aotearoa New Zealand
    (Massey University, 2025-10-13) Peters, Jonathan Bosco Alexander
    This thesis investigates the relationships between electronic media use, sleep, and fatigue. This thesis opens by introducing a conceptual framework for understanding electronic media use and evaluating terminology of sleep and fatigue concepts. The current research field of electronic media use–sleep health in adults is then mapped through an umbrella scoping review. This review revealed a predominance of correlational studies between subjective addiction symptoms and sleep satisfaction through which causal relationships were impossible to delineate. A theoretical perspective is developed on the causal interrelationships between electronic media use, sleep health difficulty, and fatigue through an investigation into experimental and theoretical studies. A novel intervention is then introduced to encourage self-directed use of electronic media in service of sleep health. The intervention is tested using a multiple-baseline single case experimental design study with sailors in active duty with Te Taua Moana O Aotearoa, The Royal New Zealand Navy. Through analysing changes in behavioural and self-report measures of electronic media use, sleep health, sleepiness, vigilance, and fatigue, no immediate effects of the intervention were observed. While longer-term improvements were observed in subjective fatigue at six-month follow-up, these could not be solely attributed to the intervention. Conceptual, theoretical, and practical complications of researching these topics are discussed throughout this thesis and summarised at the end.
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    Biomechanical comparison of titanium alloy additively manufactured and conventionally manufactured plate-screw constructs.
    (Taylor and Francis Group, 2023-12-10) Polak S; Beever L; Wade A; Fukuoka M; Worth AJ
    AIM: To biomechanically compare the bending stiffness, strength, and cyclic fatigue of titanium additively manufactured (AM) and conventionally manufactured (CM) limited contact plates (LCP) of equivalent dimensions using plate-screw constructs. METHODS: Twenty-four 1.5/2.0-mm plate constructs (CM: n = 12; AM: n = 12) were placed under 4-point bending conditions. Data were collected during quasi-static single cycle to failure and cyclic fatigue testing until implants plastically deformed or failed. Bending stiffness, bending structural stiffness, and bending strength were determined from load-displacement curves. Fatigue life was determined as number of cycles to failure. Median test variables for each method were compared using the Wilcoxon rank sum test within each group. Fatigue data was also analysed by the Kaplan-Meier estimator of survival function. RESULTS: There was no evidence for a difference in bending stiffness and bending structural stiffness between AM and CM constructs. However, AM constructs exhibited greater bending strength (median 3.07 (min 3.0, max 3.4) Nm) under quasi-static 4-point bending than the CM constructs (median 2.57 (min 2.5, max 2.6) Nm, p = 0.006). Number of cycles to failure under dynamic 4-point bending was higher for the CM constructs (median 164,272 (min 73,557, max 250,000) cycles) than the AM constructs (median 18,704 (min 14,427, max 33,228) cycles; p = 0.02). Survival analysis showed that 50% of AM plates failed by 18,842 cycles, while 50% CM plates failed by 78,543 cycles. CONCLUSION AND CLINICAL RELEVANCE: Additively manufactured titanium implants, printed to replicate a conventional titanium orthopaedic plate, were more prone to failure in a shorter fatigue period despite being stronger in single cycle to failure. Patient-specific implants made using this process may be brittle and therefore not comparable to CM orthopaedic implants. Careful selection of their use on a case/patient-specific basis is recommended.
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    Editorial: Fatigue: physiology and pathology
    (Frontiers Media S.A., 2024-02-02) Kujawski S; Zalewski P; Hodges L; Nijs J; Newton JL; Bornstein JC
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    Will night shift workers ratings of well-being and fatigue and performance on prospective memory and sustained vigilance tasks recover after three nights rest? : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Psychology at Massey University, Manawatu, New Zealand
    (Massey University, 2022) Hudson, Lucy
    As the demand for a 24-hour world increases so does the need for more shift workers. To maintain the standard expected of them, shift workers often work long hours, including night work where their main opportunity for sleep is during the day. Research has found that shift workers experience fatigue, difficulties in cognition and impaired wellbeing after working shifts like these. Despite this, minimal research has been conducted to explore how many days of recovery should be rostered after one night shift. This study aimed to find evidence to guide workplaces on how many days of rest employees should be rostered to recuperate from one night of sleep loss. A sample of 39 night shift (n=22) and day shift workers (n=17) completed a five day experiment from pre-night shift to rest day three (or five consecutive days for controls) and were assessed in tasks of prospective memory, sustained vigilance, self-reported fatigue levels and self-reported affect to measure well-being. The results indicated that while there was no significant change in vigilant attention or prospective remembering across the five days that self-reported fatigue and positive affect experienced significant changes. These findings indicate that night shift workers may need two to three days of rest to recover from some of the effects from a night of sleep deprivation. However this study repeated with a larger sample size and stricter conditions could yield different results.
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    The effect of repetitive rugby scrummaging on force output and muscle activity
    (Georg Thieme, 1/06/2017) Cochrane DJ; Harnett K; Lopez-Villalobos N; Hapeta JW
    During rugby scrummaging, front row forwards encounter high levels of force that has been suggested to cause transient fatigue and is likely to reduce subsequent performance. However, little is known about the effect of repetitive scrummaging on force output and onset of fatigue. Twelve male front row forwards (21.5 ± 2.3 yr; height 185.7 ± 4.4 cm; body mass 108.5 ± 7.1 kg) each performed three sets of five maximaleffort isometric scrums for 10 s, with 40 s rest separating each repetition; 2 min recovery was provided between each set. Force output and electromyography (EMG) of the right medial gastrocnemius (MG), biceps femoris (BF), gluteus maximus (GM), erector spinae (ES), rectus abdominis (RA), external oblique (EO), internal oblique (IO), and rectus femoris (RF) were assessed. There was no significant force decrement from performing 15 scrums and no fatigue was detected from EMG median frequency and mean amplitude. For training and practice purposes, coaches and trainers can be confident that 15 individual repetitive static scrums against a machine are unlikely to cause a reduction in force production and promote fatigue. However, the effect of rugbyrelated activities in conjunction with scrummaging requires further research to determine if transient fatigue is causal to scrummaging for subsequent performance