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As limited research has focused on the physiological responses associated with cricket activity, the aim of this pilot study was to measure selected physiological responses during batting in a simulated high-scoring 1-day cricket game. Ten male university cricketers performed a batting specific work bout consisting of four sprints per over (six balls) for a seven over period. Testing was conducted outdoors with players wearing full batting gear. All experimentation was conducted under temperate environmental conditions. During the simulated work bout, a portable on-line metabolic system (the k4b(2)) was attached to the subjects for the continuous assessment of selected physiological variables including heart rate (HR), ventilation (F(B), V(T) and V(E)), oxygen uptake (V(O2)) and metabolic carbon dioxide (V(CO2)) production. Energy expenditure was calculated from the oxygen consumption responses and substrate use was calculated from the V(O2)/V(CO2) responses. The results demonstrate that although the first over carried a statistically (p<0.05) lower energetic cost than the remaining six overs, most physiological responses stabilised thereafter. This excluded the heart rate responses which increased significantly (p<0.05) during the first three overs after which marginal increases were observed with no statistical difference between the last four overs (heart rate ranged from 149+/-19bt min(-1) in the fourth over to 155+/-18bt min(-1) in the last over). There was a mean energy expenditure of 2536kJh(-1) over the duration of the work bout. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the energy demands of manual harvesting tasks with the associated energy intake of the workers'. Fifty eight workers (29 Chainsaw Operators and 29 Stackers) were assessed in South Africa prior to, and during a 'normal' working shift. Habitual dietary analyses showed that the workers were eating less than 56% of the recommended daily allowance and were thus arriving at work with reduced energy stores. Heart rate responses were measured continuously during work and energy expenditure was predicted from the heart rate/oxygen uptake relationship obtained at a post-work progressive step up test completed by each worker. The data indicated that the tasks placed 'moderate-to-heavy' demands on the workers resulting in a significant imbalance between the energy demands of the tasks and the associated energy intake of the workers. Energy deficits were in excess of 8 000 kJ and workers lost, on average, 2.8% body mass during work while felling and cross-cutting, and 3.6% during stacking. [ABSTRACT FROM AUTHOR]

Objectives: This study assessed the metabolic responses of South African soldiers marching at different speeds and carrying varying loads. The main objective was to establish the physiological cost of a range of speed/load combinations to identify the energy requirements to meet a diversity of march objectives.Methods: Thirty male soldiers marched on a treadmill for 6 minutes with varying combinations of speed and load, established through numerous pilot studies and in consultation with military personnel. The four speeds were 3.5, 4.5, 5.5, and 6.5 km x (-1), combined with the four loads of 20, 35, 50, and 65 kg, totaling 16 combinations. Each participant completed eight of the 16 conditions, during which the participants wore standardized military gear and were attached to a portable ergospirometer (the Metamax, Cortex, Leipzig, Germany) for the duration of the march.Results: Based on the responses, five discrete categories of speed/load combinations were identified. These combinations were categorized as nominal (< 40% of maximal oxygen consumption [VO(2max)]), moderate (40-50% of VO(2max)), heavy (50-65% of VO(2max)), very heavy (65-80% of VO(2max)), and excessive (> 80% of VO(2max)), with each categorization incorporating diverse combinations of speed and load.Conclusion: The findings demonstrate that the interplay between marching speed and backpack load plays a crucial role in ensuring that similar metabolic demands are maintained at a bearable level to meet specific military circumstances, thus reducing the likelihood of injuries and the early onset of fatigue and ensuring that the soldiers are combat ready on arrival at their destination. [ABSTRACT FROM AUTHOR]

Introduction: Sunglasses are worn by outdoor athletes such as cricketers for many reasons, including comfort and glare reduction, which may help to improve vision. Anecdotally they are purported to have performance-enhancing benefits, but there is a lack of evidence for this. Further, it appears that fielders are the only position in cricket who wear sunglasses. Therefore, this study aimed to compare the catching performance of fielders when wearing three different colour sunglasses tints during an indoor, laboratory-based experiment., Methods: Twenty-one male cricketers currently playing for a university or amateur provincial teams in Makhanda, South Africa, who were non-habitual sunglass wearers, were recruited for this study. An optometrist administered pre-screening tests. Players had four testing sessions during which they wore a different colour tint at each session indoors (clear, blue, G30 (rose), and red). Players were required to catch 18 balls projected from a bowling machine. The number of balls caught, as well as the quality of the catch, was recorded. At the final session, they were asked which tint they thought was best., Results: Pre-screening tests showed that the red lens was best for contrast sensitivity and stereopsis. During data collection, sunglass tint did not affect catching performance. The players perceived the red lens as the worst and the G30 as the best., Discussion: It can be concluded that catching performance indoors is not affected by tint colour., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Christie, Nellemann, Davies, Fourie and Davy.)

Background: The Global Matrix 4.0 on physical activity (PA) for children and adolescents was developed to achieve a comprehensive understanding of the global variation in children's and adolescents' (5-17 y) PA, related measures, and key sources of influence. The objectives of this article were (1) to summarize the findings from the Global Matrix 4.0 Report Cards, (2) to compare indicators across countries, and (3) to explore trends related to the Human Development Index and geo-cultural regions., Methods: A total of 57 Report Card teams followed a harmonized process to grade the 10 common PA indicators. An online survey was conducted to collect Report Card Leaders' top 3 priorities for each PA indicator and their opinions on how the COVID-19 pandemic impacted child and adolescent PA indicators in their country., Results: Overall Physical Activity was the indicator with the lowest global average grade (D), while School and Community and Environment were the indicators with the highest global average grade (C+). An overview of the global situation in terms of surveillance and prevalence is provided for all 10 common PA indicators, followed by priorities and examples to support the development of strategies and policies internationally., Conclusions: The Global Matrix 4.0 represents the largest compilation of children's and adolescents' PA indicators to date. While variation in data sources informing the grades across countries was observed, this initiative highlighted low PA levels in children and adolescents globally. Measures to contain the COVID-19 pandemic, local/international conflicts, climate change, and economic change threaten to worsen this situation.

Abstract: Weldon, A, Duncan, MJ, Turner, A, LaPlaca, D, Sampaio, J, and Christie, CJ. Practices of strength and conditioning coaches: a snapshot from different sports, countries, and expertise levels. J Strength Cond Res 36(5): 1335-1344, 2022-This study describes the practices of strength and conditioning coaches (SCCs) from different sports, countries, and expertise levels. One hundred fifty-six SCCs (31.9 ± 8.9 years old) completed an online survey, consisting of 40 questions (36 fixed response and 4 open-ended), with 8 sections as follows: (a) background information, (b) muscular strength and power development, (c) speed development, (d) plyometrics, (e) flexibility development, (f) physical testing, (g) technology use, and (h) programming and any additional comments. Responses were received from 48 sports and 17 countries. This study provides exploratory evidence incorporating responses primarily in soccer (45%), track and field (30%), volleyball (23%), golf (17%), and tennis (17%). A bachelor's degree or higher were held by 99% of SCCs, of which 94% were in a sports science-related field, and 71% held a strength and conditioning related certification or accreditation. Periodization strategies and physical testing were used by 96% and 94% of SCCs respectively. The hang clean (82%), power clean (76%), and clean high pull (63%) were the most prescribed Olympic weightlifting exercises. Multiple hops/lunges (84%) were the most prescribed plyometrics exercises. For open-ended questions, 40% of SCCs wanted to integrate more technology into their programs and 30% believed technology will be the main future trend. Strength and conditioning coaches from different sports, countries, and expertise levels can use the information presented in this study to review their current practices and provide a source of new ideas for diversifying or modifying future practices., (Copyright © 2020 National Strength and Conditioning Association.)

During lockdowns associated with the COVID-19 pandemic, individuals have experienced poor sleep quality and sleep regularity, changes in lifestyle behaviours, and heightened depression and anxiety. However, the inter-relationship and relative strength of those behaviours on mental health outcomes is still unknown. We collected data between 12 May and 15 June 2020 from 1048 South African adults (age: 32.76 ± 14.43 years; n = 767 female; n = 473 students) using an online questionnaire. Using structural equation modelling, we investigated how insomnia symptoms, sleep regularity, exercise intensity/frequency and sitting/screen-use (sedentary screen-use) interacted to predict depressive and anxiety-related symptoms before and during lockdown. We also controlled for the effects of sex and student status. Irrespective of lockdown, (a) more severe symptoms of insomnia and greater sedentary screen-use predicted greater symptoms of depression and anxiety and (b) the effects of sedentary screen-use on mental health outcomes were mediated by insomnia. The effects of physical activity on mental health outcomes, however, were only significant during lockdown. Low physical activity predicted greater insomnia symptom severity, which in turn predicted increased depressive and anxiety-related symptoms. Overall, relationships between the study variables and mental health outcomes were amplified during lockdown. The findings highlight the importance of maintaining physical activity and reducing sedentary screen-use to promote better sleep and mental health., (© 2021. The Author(s).)

Background: The authors assessed the impact of lockdown in response to the COVID-19 pandemic on routine-oriented lifestyle behaviors and symptoms of depression, anxiety, and insomnia in South Africans., Methods: In this observational study, 1048 adults (median age = 27 y; n = 767 females; n = 473 students) responded to an online survey on work, exercise, screen, alcohol, caffeine and sleep behaviors, depression, anxiety, and insomnia before and during lockdown. Comparisons were made between males and females, and students and nonstudents., Results: During lockdown, males reported larger reductions in higher intensity exercise and alcohol use than females, while depressive symptoms increased more among females, more of whom also reported poorer sleep quality. Students demonstrated larger delays in work and sleep timing, greater increases in sitting, screen, sleep duration, napping, depression and insomnia and larger decreases in work hours, exercise time, and sleep regularity compared with nonstudents., Conclusions: Students experienced more changes in their routine-oriented behaviors than nonstudents, coupled with larger increases in depression and insomnia. The dramatic change in their work and sleep timing suggests habitual routines that are at odds with their chronotype, with their sleep changes during lockdown likely reflecting "catch-up" sleep in response to accumulated sleep debt under usual routines.

Despite evidence supporting the positive affect sleep has on sport performance, there is limited application of sleep research in cricket. This study investigated the sleep behaviours of 26 elite South African cricket players (28.6 ± 4.0 years) during home and away competition. Players completed an altered version of the Core Consensus Sleep Diary every morning post-travel, pre-match and post-match. Linear mixed model regression was used to compare differences in sleep between time-periods, venues and formats. Spearman's correlations (r s ) assessed the relationship of match performance and sleep. Post-match total sleep time (06:31 ± 01:09) was significantly (p < 0.05) shorter compared to post-travel (07:53 ± 01:07; g = 1.19) and pre-match (08:43 ± 01:03; g = 1.98). Post-travel sleep onset latency and sleep efficiency were significantly shorter (-20; g = 1.35) and higher (+10.4%; g = 0.74) at home than away respectively. Longer sleep onset latencies and shorter total sleep times were significantly associated with poorer One-Day International (r s  = -0.57) and Test (r s  = 0.59) batting performances respectively. The poor post-match sleep behaviour, and the sleep and performance correlations, provide motive for future interventions to focus on recovery and the use of sleep monitoring as a competitive advantage.

Workload monitoring is used to assess athlete preparedness to ensure that they are optimally prepared for competition. Although many workload studies have been done, most are delimited to individual sport athletes and endurance athletes. There is also controversy regarding which measures and in what combinations they should be used. There is a paucity of literature on workload monitoring in team sports such as cricket. Cricket is an interesting and complex sport which has dimensions of many other sports (team and individual) and was the focus of this broad, narrative review. The review highlights the unique demands of the sport and why consideration of the sport in question is important. It further identifies that most of the workload research has been done on fast bowlers with debate surrounding optimal workloads. It calls for research in specific areas and importantly on other player positions considering their unique demands and identifies what can be used currently by practitioners in the field., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest, (© Indian Orthopaedics Association 2020.)

There is a lack of research on the movement patterns within Twenty20 (T20) cricket, thus the purpose of this study was to investigate the movement demands placed on elite T20 cricket players playing in The Big Bash League, in Australia, in the 2017/2018 season. Player positional movements were determined from the time motion data obtained from a portable 10 Hz global positioning (GPS) unit. Overall, all the players covered between 1.77km and 6.54km in a time ranging between 40.4 minutes and 96.5 minutes. Fast bowlers covered a mean distance of 6.5 (±0.5) km, batsmen 1.7 (±1.2) km and fielders 5.9 (±0.9) km. This is the first study that has looked at the movement demands of players in The Big Bash League and found that bowlers have the highest movement demands followed by fielding. With that, arguably, more attention needs to be devoted to bowling and particularly fielding which is often not prioritized. However, overall demands of T20 cricketers have decreased. Cricketers and coaches need to ensure that they adapt training to ensure that their players are physically prepared for the associated demands., (© Journal of Sports Science and Medicine.)

Background: There is minimal research on workloads of adolescent rugby players. Therefore, the main aim of this study was to determine the workloads placed on a cohort of South African adolescent rugby players (n = 17), during an in-season period., Methods: Session RPE ratings were collected daily, 30 minutes after the training session concluded, during an 11-week in-season period. The training load was calculated as the session ratings of perceived exertion multiplied by the session's duration (min)., Results: The main finding of the study was that the adolescents in this investigation had similar workloads to elite players but higher workloads than other studies on adolescent rugby players. The forwards (3311±939 arbitrary units; AU) had a higher workload than backline players (2851±1080 AU). There was no difference between forwards and backline players with regards to the acute:chronic workload ratio., Conclusion: Workloads are high in these adolescent players, particularly in the forwards, and are similar to the workloads of elite level rugby players., Competing Interests: Conflict of interest and source of funding: The authors declare that they have no conflict of interest and no source of funding.

Background: The purpose of this investigation was to determine the strength and conditioning practices implemented by cricket trainers and coaches at an elite level., Methods: An online survey, adapted from previous strength and conditioning questionnaires, was sent to trainers currently working with the franchise cricket teams in South Africa. The survey consisted of four main sections including a general strength and conditioning, cricket- specific and injury prevention category., Results: The results indicated that trainers (n = 5) implement planned sessions throughout the different phases of the season and that certain injury prevention practices are applied. Furthermore, player workload is monitored for all disciplines (batsmen, bowlers and fielders)., Conclusion: These results can be used as a tool to educate coaches and trainers to ensure the correct strength and conditioning practices are implemented. Additionally the study showed that strength and conditioning practices at the elite level can be implemented without specialised equipment and facilities, which is important for teams that are constantly travelling. Lastly it showed the importance of looking at all aspects of health and skill related fitness., Competing Interests: Conflict of interest and source of funding: The authors declare that they have no conflict of interest and no source of funding.

Christie CJ, Sheppard B, Goble D, Pote L, and Noakes TD. Strength and sprint time changes in response to repeated shuttles between the wickets during batting in cricket. J Strength Cond Res 33(11): 3056-3064, 2019-No studies have investigated the impact of repeated sprints between the wickets on lower-limb strength and sprint performance. Therefore, the purpose of this study was to assess changes in knee extensor (EXT) and flexor (FLEX) strength after repeated sprints between the wickets and to relate these to changes in sprint times. Twenty batters completed 2 conditions: one was high-volume running (HVR-twelve sprints per over) and the other, moderate-volume running (MVR-6 sprints per over) between the wickets (42 deliveries in both). Peak isokinetic torque was measured before and after each condition and sprint times were recorded. Eccentric and concentric peak torque decreased significantly (p < 0.05) at 1.05 rad·s for knee EXT in both conditions. There was an 18% (HVR) and 10% (MVR) decline in concentric and eccentric knee EXT peak torque. Peak FLEX torques were significantly (p < 0.05) reduced after HVR (16.7%) but not after the MVR condition (8%). There were similar declines in eccentric FLEX peak torque. Sprint times increased significantly (p < 0.05) during the HVR condition but not in the MVR condition; sprint times in the HVR condition were compromised as early as the third over. We conclude that a high volume of runs significantly reduces muscle function in the lower limbs, partly explaining the impairment in sprint performance. However, because batters slowed as early as the third over in the HVR condition, there may be some form of strategy used in anticipation of a higher overall workload. More middle wicket practices, focusing on repeat shuttle sprints while batting, should be included in the coaching program.

Background: The demands placed on fast bowlers may elicit unique responses that contribute towards increased injury risk and comprised performance capabilities. Despite this, very few investigations have attempted to quantify these demands and their impact on performance in cricketers., Objective: This investigation attempted to quantify the effects of a fast bowling protocol on the musculoskeletal, physiological and perceptual responses of fast bowlers; as well as ball speed and accuracy., Methods: Eight young adult bowlers (20 ± 2 years) participated in a 10-over bowling protocol that had been separated by intermittent fielding drills into three bowling spells respectively (4-, 3- and 3- overs). Selected responses were collected throughout the protocol., Results: Functional strength was measured and showed no change. Heart rate responses increased significantly (p<0.05) at the start of the bowling protocol. Local ratings of perceived exertion increased significantly (p<0.05) as a function of exercise duration, while low to moderate intensities of perceived discomfort were noted in the anterior and posterior shoulder areas, upper portion of the lower limb musculature, as well as in the middle and lower back regions. Performance responses experienced no significant change., Conclusion: There was no significant change in ball release speed and accuracy across the bowling protocol. Lower limb muscle power remained consistent and heart rates reached a steady state after the first over. In comparison, local ratings of perceived effort and body discomfort increased over time, which could mean that those unchanged measures do not accurately reflect fatigue or that perceptions are a more effective indicator of impending fatigue., Competing Interests: Conflict of interest and source of funding: None, (Copyright © 2019 South African Journal of Sports Medicine.)

Objectives: To assess whether the absence of a known endpoint, at the beginning of repeated-sprint bouts between the wickets, affects how skilled compared to less skilled batsmen pace themselves., Design: Repeated measures., Methods: Twelve skilled and 12 less skilled batsmen completed three trials. All trials required the same number of sprints (14 shuttles, 28 runs), while only the information before each trial differed. CT: batsmen were aware of the endpoint (28 runs). UT: not informed of the exercise endpoint and were required to run on command for an indefinite period (28 runs). DT: told they were only doing 14 runs when they actually did 28 runs. Sprint times, electrical muscle activity, and ratings of perceived effort were recorded., Results: Skilled batsmen were significantly faster than less skilled across all trials. Hamstring muscles activity decreased significantly over time in the skilled players during the UT, and during the CT and DT for the less skilled players. There were significant reductions in quadriceps muscles activation for the less skilled over time in all trials and in the skilled batsmen in the vastus medialis during the UT only. Perceived effort increased significantly in both groups in all trials. Skilled batsmen were fastest in the UT and less skilled fastest in the CT., Conclusions: Better batting skill facilitated improved sprint times, especially when the exact endpoint was unknown. These results suggest that less skilled players should be given more central wicket practice with uncertainty to better develop their ability to maintain their sprint performance., (Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

The purpose of this study was to assess how cognitive and physical performance are affected during a prolonged, fatigue-inducing cricket-batting simulation. Fifteen amateur batters from three Eastern Cape schools in South Africa were recruited (mean ± SD: age 17 ± 0.92 years; stature 1.75 ± 0.07 m; body mass 78.3 ± 13.2 kg). Participants completed a 6-stage, 30-over batting simulation (BATEX © ). During the protocol, there were five periods of cognitive assessment (CogState brief test battery, Melbourne, Australia). The primary outcome measures from each cognitive task were speed and accuracy/error rates. Physiological (heart rate) and physical (sprint times) responses were also recorded. Sprint times deteriorated (d = 0.84; P < 0.01) while physiological responses increased (d = 0.91; P < 0.01) as batting duration increased, with longest times and highest responses occurring in the final stage. Prolonged batting had a large effect on executive task performance (d = 0.85; P = 0.03), and moderate effects on visual attention and vigilance (d = 0.56; P = 0.21) and attention and working memory (d = 0.61; P = 0.11), reducing task performance after 30 overs. Therefore, prolonged batting with repeated shuttle running fatigues amateur batters and adversely affects higher-order cognitive function. This will affect decision-making, response selection, response execution and other batting-related executive processes. We recommend that training should incorporate greater proportions of centre-wicket batting with repeated, high-intensity shuttle running. This will improve batting-related skills and information processing when fatigued, making practice more representative of competition.

Pote, L and Christie, CJ. Strength and conditioning practices of University and high school level cricket coaches: a South African context. J Strength Cond Res 30(12): 3464-3470, 2016-Although the sport of cricket is well established, the strength and conditioning practices of cricket players are not well known. Therefore, the purpose of this study was to examine the current strength and conditioning practices that coaches implement for South African schoolboy and University level cricket players. An online survey, adapted from previous strength and conditioning questionnaires, was sent to 38 schoolboy and 12 University teams that participated in the top competitions in the country (n = 50). Of these, 24 replied indicating a response rate of 48%. Results indicated that although some forms of conditioning, workload monitoring and injury prevention were being implemented, the correct practices were not being administered. Furthermore, it was identified that most coaches had insufficient qualifications and experience to administer the correct training techniques. It was concluded that coaches require further education so that scientifically based training programs can be implemented. This was deemed particularly necessary for adolescent bowlers who are at an increased risk of injury, specifically in the lower back region.

Few studies have examined the impact of an increased physical demand on batting performance, especially over extended periods of play. Therefore, the purpose of this study was to determine the physiological and perceptual responses of batsmen scoring a simulated limited overs century, and to link these to sprint times and accuracy of the impact of the ball on the bat. Seventeen male, university level cricketers, performed a batting protocol (BATEX(©)), typical of a limited overs century. The protocol consisted of six stages, each of five overs, with each stage matched to a specific phase of play. Throughout the protocol heart rate (HR), central ratings of perceived effort (RPE), sprint times and impact accuracy were recorded. HR fluctuated as a function of exercise intensity (124.16-159.61 bpm). Central RPE increased as a function of intensity and duration (11.87-16.04). Sprint times got slower over time (5.67-5.81 s), while impact accuracy improved significantly (p < .05) after stage one and then plateaued for the remainder of the protocol (64.81-57.39 mm). In conclusion, the protocol significantly impacted cardiac strain and perceptual responses negatively impacting sprint times with an improvement in batting accuracy.

Background: Understanding motivators for exercise participation in post-menopausal women may impact retention to exercise programmes and inform intervention trial designs. The purpose of this investigation was to assess self-reported motivational factors influencing adherence and retention to a 24-week progressive resistance training programme., Methods: Post-menopausal females (n = 34) were passively recruited to undertake a 24-week progressive resistance training protocol, in small-group sessions, on three non-consecutive days of the week. Attendance was recorded by the researcher. Qualitative reports were sourced from the sample for four phases of the study: pre-study (prior to week 1), recruitment (week 1), during study (weeks 2 - 24), and post-intervention (beyond week 24). Responses were categorised according to ten descriptors: specific health index improvement, education, flexibility of time, social contact, conscience (loyalty to the researcher), wellness, weight management, organisation parameters (pertaining to the study programme) and enjoyment of the exercises., Results: Of the initial sample, 76.5% (n = 26) met the specified ≥80% attendance criterion. The primary findings were that motivation to volunteer for the study was driven by a perceived need for a structured exercise programme (50% of respondents). A commitment to the researcher was the primary motivator for continued adherence to the study for 50% of participants. Social contact with other participants was cited by 60% of the sample as the primary reason for adherence for the full duration of 24 weeks. A desire to maintain the "wellness" derived from the programme was cited by 60% as a reason for continuing an exercise routine post-study., Conclusion: This study identified that routine and supervision initially attract women to exercise programmes, while social cohesion of the group setting contributes to retention over time. Understanding the changing nature of motivating factors may contribute to better overall adherence and retention to exercise programmes and interventions.

Objective: To compare physiological and perceptual responses while lifting with different combinations of ceiling restriction and horizontal reach., Methods: Four lifting conditions with different combinations of ceiling height ('normal' (N) or reduced (R) to 1460 mm) and reach demands (400 mm (N) and 800 mm (F)) were tested., Participants: Thirty two physically active male participants were recruited., Results: Heart rate and oxygen uptake were significantly lower in the URN condition compared to all other conditions. The RF condition was significantly more taxing than all the other conditions. EE was significantly lower between the URN condition and the RN and URF conditions. Central RPE was significantly higher in the RF condition compared to the URN condition. Local RPE was significantly lower comparing the URN and RF conditions. The effect of reach was perceived to have a significant effect on both cardiovascular and musculoskeletal demands whereas ceiling height only had a significant effect on musculoskeletal demands. The greatest discomfort was experienced in the lower back with the most intense discomfort occurring in the RN condition., Conclusions: The RF condition placed the most strain on the participants and the URN, the least strain. The other two conditions were comparable and placed moderate strain on the participants.

The HLA typing of hemodialysis patients and normal subjects suggests a negative association of B8 and positive association of B5 with the development of anti-HBs and a negative association of BW35 with HBsAg antigenemia.