Recent Submissions

  • Breaking up sitting with short frequent or long infrequent physical activity breaks does not lead to compensatory changes in appetite, appetite-regulating hormones or energy intake

    Maylor, Benjamin David; Zakrzewski-Fruer, Julia K.; Stensel, David J.; Orton, Charlie J.; Bailey, Daniel Paul; ; University of Bedfordshire; Leicester General Hospital; Loughborough University; Waseda University; et al. (Elsevier, 2022-12-30)
    The aim of this study was to determine the appetite-related responses to breaking up prolonged sitting with physical activity bouts differing in frequency and duration among adult females. Fourteen sedentary females aged 34 ± 13 years with a body mass index of 27.1 ± 6.3 kg/m2 (mean ± SD) took part in a randomised crossover trial with three, 7.5 h conditions: (1) uninterrupted sitting (SIT), (2) sitting with short frequent 2-min moderate-intensity walking breaks every 30 min (SHORT-BREAKS), and (3) sitting with longer duration, less frequent 10-min moderate-intensity walking breaks every 170–180 min (LONG-BREAKS). The intensity and total duration of physical activity was matched between the SHORT-BREAKS and LONG-BREAKS conditions. Linear mixed models were used to compare the outcomes between conditions with significance being accepted as p ≤ 0.05. There were no significant between-condition differences in hunger, satisfaction, prospective food consumption or overall appetite area under the curve (AUC) (all p ≥ 0.801). Absolute ad libitum energy intake and relative energy intake (REI) did not differ significantly between conditions (all p ≥ 0.420). Acylated ghrelin and total peptide YY incremental and total AUC did not differ significantly between conditions (all p ≥ 0.388). Yet, there was a medium effect size for the higher acylated ghrelin incremental AUC in SHORT-BREAKS versus SIT (d = 0.61); the reverse was seen for total AUC, which was lower in SHORT-BREAKS versus SIT (d = 0.69). These findings suggest that breaking up sitting does not lead to compensatory changes in appetite, appetite hormones or energy intake regardless of physical activity bout duration and frequency among adult females.
  • Cardiac structure and function in resistance-trained and untrained adults: a systematic review and meta-analysis

    Saunders, Abigail M.; Jones, Rebecca; Richards, Joanna C.; ; University of Bedfordshire; University of Lincoln (Taylor and Francis, 2022-11-18)
    Variations in the haemodynamic demands of specific training modalities may explain characteristic differences in cardiac structure and function amongst athletes. However, current consensus regarding these adaptations in highly resistance-trained athletes is yet to be established. The current invetsigation aimed to collate research investigating cardiac structure and function in resistance-trained athletes, exploring the defining characteristics of Athlete’s Heart within these individuals. Seven electronic databases were searched. Studies which examined at least one measure of cardiac structure or function, included healthy, normotensive male or females (>18 years) and compared athletes engaged in a resistance training programme (>12 months) to an untrained group engaged in no structured training programme were included. Systematic selection and quality appraisal of articles was performed by two reviewers, with a random effects meta-analysis model applied to suitable studies. Studies were limited to orginal peer-reviewed articles published in English. Resistance-trained athletes (n = 949) demonstrated greater cardiac dimensions compared to their untrained counterparts (n = 1053). No clear impairments to systolic or diastolic cardiac function were observed in athletic population studied here. Resistance-trained athletes display some characteristics of the Athlete's Heart phenomenon, including greater wall thickening and chamber dilation compared to their untrained counterparts.
  • Sedentary behaviour : a target for the prevention and management of cardiovascular disease

    Bell, Abbie C.; Richards, Joanna C.; Zakrzewski-Fruer, Julia K.; Smith, Lindsey Rachel; Bailey, Daniel Paul; ; University of Bedfordshire; Brunel University London (MDPI, 2022-12-28)
    Cardiovascular disease (CVD) is highly prevalent and can lead to disability and premature mortality. Sedentary behaviour, defined as a low energy expenditure while sitting or lying down, has been identified as an independent risk factor for CVD. This article discusses (1) the association of total sedentary time and patterns of accumulating sedentary time with CVD risk markers, CVD incidence and mortality; (2) acute experimental evidence regarding the acute effects of reducing and breaking up sedentary time on CVD risk markers; and (3) the effectiveness of longer-term sedentary behaviour interventions on CVD risk. Findings suggest that under rigorously controlled laboratory and free-living conditions, breaking up sedentary time improves cardiovascular risk markers in individuals who are healthy, overweight or obese, or have impaired cardiovascular health. Breaking up sedentary time with walking may have the most widespread benefits, whereas standing breaks may be less effective, especially in healthy individuals. There is also growing evidence that sedentary behaviour interventions may benefit cardiovascular risk in the longer term (i.e., weeks to months). Reducing and breaking up sedentary time may, therefore, be considered a target for preventing and managing CVD. Further research is needed to determine the effectiveness of sedentary behaviour interventions over the long-term to appropriately inform guidelines for the management of CVD. Keywords: sedentary behaviour; cardiovascular disease; prolonged sitting; cardiovascular risk markers
  • Changes in peak force output, rate of force development, and jump performance across a full season in elite English rugby union players

    Chrismas, Bryna C.; Fletcher, Iain M.; Hogben, Patrick; Qatar University; University of Bedfordshire (Sport Performance & Science Reports, 2020-03-31)
    Rugby union is a high-intensity invasion game characterised by contact events (most frequently the tackle and ruck). Success in key defining moments (i.e. tackle breaks, turnovers, scrums) in elite level rugby union is therefore largely dependent on technical characteristics, and physical qualities including strength and speed (1). Understanding changes in force characteristics across the full English professional rugby union season is therefore important for creating and monitoring strength and conditioning programmes. The aim of this study was to examine changes in force output, rate of force development (RFD), and jump performance across the full season in elite male English rugby union players.
  • Effects of active warm-up & warm-up massage on agility, perceived exertion & flexibility in tennis players

    Bedford, S.; Robbins, D.; Fletcher, Iain M. (Society for Tennis Medicine and Science, 2018-12-31)
  • The effects of kicking leg preference on balance ability in elite soccer players

    Fletcher, Iain M.; Long, Christopher S.; University of Bedfordshire (SciTechnol, 2013-07-15)
    with leg asymmetry linked to this injury occurrence. Screening for balance deficits is used as a predictor of potential injury; therefore the aim of this study was to determine whether static and dynamic balance differs in elite soccer players preferred kicking and nonpreferred kicking legs. Fifteen male professional soccer players were tested for static balance; standing on one leg, and dynamic balance, a hop and hold task and a kicking task. Balance ability was assessed by measuring centre of pressure deviation. Results indicated that static balance and hop and hold tests were not significantly different (p>0.05) when dominant and non-dominant kicking legs were compared. The kicking balance task indicated a significant increase (p≤0.05) in balance ability for the player’s nondominant limbs. Further, left sided players had significantly better (p≤0.05) dominant leg balance when compared to right sided players. These findings suggest that the static and dynamic balance tasks employed in this study were not specific enough to establish possible balance asymmetries in professional elite soccer players, while the passing dynamic balance test seems to be sensitive enough to show dominant and non-dominant leg discrepancies. It is therefore suggested that balance tasks, used to screen players, need to mimic the actions linked to injuries within soccer in order to explore dominant and non-dominant asymmetry.
  • The acute effects of combined static and dynamic stretch protocols on 50m sprint performance in track and field athletes

    Fletcher, Iain M.; Anness, Ruth; ; University of Luton (Lippincott, Williams & Wilkins, 2007-05-31)
    The purpose of this study was to investigate the effect of manipulating the static and dynamic stretch components associated with a traditional track-and-field warm-up. Eighteen experienced sprinters were randomly assigned in a repeated-measures, within-subject design study with 3 interventions: active dynamic stretch (ADS), static passive stretch combined with ADS (SADS), and static dynamic stretch combined with ADS (DADS). A standardized 800-m jogged warm-up was performed before each different stretch intervention, followed by two 50-m sprints. Results indicated that the SADS intervention yielded significantly (p < or = 0.05) slower 50-m sprint times then either the ADS or DADS intervention. The decrease in sprint time observed after the ADS intervention compared to the DADS intervention was found to be nonsignificant (p > 0.05). The decrease in performance post-SADS intervention was attributed to a decrease in the musculotendinous unit (MTU) stiffness, possibly due to a reduction in muscle activation prior to ground contact, leading to a decrease in the MTU's ability to store and transfer elastic energy after the use of passive static stretch techniques. The improved 50-m sprint performance associated with the ADS and DADS interventions was linked to the rehearsal of specific movement patterns, helping proprioception and preactivation, allowing a more optimum switch from eccentric to concentric muscle contraction. It was concluded that passive static stretching in a warm-up decreases sprint performance, despite being combined with dynamic stretches, when compared to a solely dynamic stretch approach.
  • The effect of different warm-up stretch protocols on 20m-sprint performance in trained rugby union players

    Fletcher, Iain M.; Jones, Bethan; ; University of Luton (Lippincott, Williams & Wilkins, 2004-11-30)
    The purpose of this study was to determine the effect of different static and dynamic stretch protocols on 20-m sprint performance. The 97 male rugby union players were assigned randomly to 4 groups: passive static stretch (PSS; n = 28), active dynamic stretch (ADS; n = 22), active static stretch (ASST; n = 24), and static dynamic stretch (SDS; n = 23). All groups performed a standard 10-minute jog warm-up, followed by two 20-m sprints. The 20-m sprints were then repeated after subjects had performed different stretch protocols. The PSS and ASST groups had a significant increase in sprint time (p ≤ 0.05), while the ADS group had a significant decrease in sprint time (p ≤ 0.05). The decrease in sprint time, observed in the SDS group, was found to be nonsignificant (p ≥ 0.05). The decrease in performance for the 2 static stretch groups was attributed to an increase in the musculotendinous unit (MTU) compliance, leading to a decrease in the MTU ability to store elastic energy in its eccentric phase. The reason why the ADS group improved performance is less clear, but could be linked to the rehearsal of specific movement patterns, which may help increase coordination of subsequent movement. It was concluded that static stretching as part of a warm-up may decrease short sprint performance, whereas active dynamic stretching seems to increase 20-m sprint performance.
  • The effect of an 8-week combined weights and plyometrics training programme on golf drive performance

    Fletcher, Iain M.; Hartwell, Matthew; ; Exercise Physiology Laboratory; University of Luton (Lippincott, Williams & Wilkins, 2004-02-28)
    The purpose of this study was to determine the effect of a combined weights and plyometrics program on golf drive performance. Eleven male golfers' full golf swing was analyzed for club head speed (CS) and driving distance (DD) before and after an 8-week training program. The control group (n = 5) continued their normal training, while the experimental group (n = 6) performed 2 sessions per week of weight training and plyometrics. Controls showed no significant (p > or = 0.05) changes, while experimental subjects showed a significant increase (p < or = 0.05) in CS and DD. The changes in golf drive performance were attributed to an increase in muscular force and an improvement in the sequential acceleration of body parts contributing to a greater final velocity being applied to the ball. It was concluded that specific combined weights and plyometrics training can help increase CS and DD in club golfers.
  • Foundations of strength & conditioning

    Archer, E.; Brannigan, J.; Fletcher, Iain M.; Sargent, D. (UK Strength and Conditioning Association, 2022-08-31)
  • Biomechanics of running

    Fletcher, Iain M.; Charalambous, Laura H. (Ivy Press, 2019-02-07)
  • Jenny: specialist needs for the specialising phase

    Harvey, Stephen; Pope, Stacey; Fletcher, Iain M.; Kerner, Charlotte Lynn (Routledge, 2014-12-31)
    Jenny is a 13-year-old field hockey player from Nottingham in England, which is an area with a population of over 600,000 people. Her parents are White-British and they both work full-time, sometimes including the weekends. Together they earn around £30,000 per annum, which puts them in the category of below average earners in England.1 Jenny has one brother who trains at a well known football club’s academy for talented young players. Her mother and father spend much of their spare time supporting him by providing transport to training sessions and, where possible, accompanying him to matches at weekends. Jenny’s parents are wholly supportive of her brother’s aspirations to be a professional football player, but they are less certain about Jenny’s ambitions to play elite level hockey as it does not offer the same financial incentive.
  • RPE-derived work rates can be accurately produced without external feedback or reference to the RPE scale

    Mauger, Alexis R.; Huntley, Tabo; Fletcher, Iain M.; (SAGE, 2014-04-01)
    Ratings of perceived exertion (RPE) are used to prescribe exercise intensity. This study assessed whether the accurate production of exercise intensity is affected when the rater cannot see the RPE scale. After completing a graded exercise test, 15 active, male participants (M age = 34, SD = 6.7 yr.; M mass = 73.9, SD = 14.8 kg, M height = 1.74, SD = 0.08 m) completed 3 × 4 min. cycling trials at four randomised RPE-based intensities (RPEs 11, 13, 15, and 17). Participants were allocated to a Full feedback group or a No feedback group (RPEs not in view). On the third trial, No feedback conditions were imposed on the Full feedback group. No statistically significant differences between groups' mean work rates were observed. Changing from Full feedback to No feedback conditions led to a significant overestimation between the trials for power output at RPE 11. Intra-class correlations were significant at RPEs 11, 13, and 17 between all trials for both conditions. Provided adequate familiarisation, active participants can accurately produce RPE derived work rates, even when RPE is not in view.
  • Is BMI alone a sufficient outcome to evaluate interventions for child obesity?

    Kolotourou, Maria; Radley, Duncan; Chadwick, Paul; Smith, Lindsey Rachel; Orfanos, Stavros; Kapetanakis, Venediktos; Singhal, Atul; Cole, Tim J.; Sacher, Paul M.; ; et al. (Mary Ann Liebert, 2013-06-15)
    Background: BMI is often used to evaluate the effectiveness of childhood obesity interventions, but such interventions may have additional benefits independent of effects on adiposity. We investigated whether benefits to health outcomes following the Mind, Exercise, Nutrition...Do It! (MEND) childhood obesity intervention were independent of or associated with changes in zBMI. Methods: A total of 79 obese children were measured at baseline; 71 and 42 participants were followed-up at 6 and 12 months respectively, and split into four groups depending on magnitude of change in zBMI. Differences between groups for waist circumference, cardiovascular fitness, physical and sedentary activities, and self-esteem were investigated. Results: Apart from waist circumference and its z-score, there were no differences or trends across zBMI subgroups for any outcome. Independent of the degree of zBMI change, benefits in several parameters were observed in children participating in this obesity intervention. Conclusion: We concluded that isolating a single parameter like zBMI change and neglecting other important outcomes is restrictive and may undermine the evaluation of childhood obesity intervention effectiveness. © Copyright 2013, Mary Ann Liebert, Inc. 2013.
  • Assessing the short-term outcomes of a community-based intervention for overweight and obese children: the MEND 5-7 programme

    Smith, Lindsey Rachel; Chadwick, Paul; Radley, Duncan; Kolotourou, Maria; Gammon, Catherine; Rosborough, J.; Sacher, Paul M.; University College London; MEND (BMJ Publishing Group, 2013-05-03)
    Objective: The aim of this study was to report outcomes of the UK service level delivery of MEND (Mind, Exercise, Nutrition ⋯ Do it!) 5-7, a multicomponent, community-based, healthy lifestyle intervention designed for overweight and obese children aged 5-7 years and their families. Design: Repeated measures. Setting: Community venues at 37 locations across the UK. Participants: 440 overweight or obese children (42% boys; mean age 6.1 years; body mass index (BMI) z-score 2.86) and their parents/carers participated in the intervention. Intervention: MEND 5-7 is a 10-week, family-based, child weight-management intervention consisting of weekly group sessions. It includes positive parenting, active play, nutrition education and behaviour change strategies. The intervention is designed to be scalable and delivered by a range of health and social care professionals. Primary and secondary outcome measures: The primary outcome was BMI z-score. Secondary outcome measures included BMI, waist circumference, waist circumference z-score, children's psychological symptoms, parenting self-efficacy, physical activity and sedentary behaviours and the proportion of parents and children eating five or more portions of fruit and vegetables. Results: 274 (62%) children were measured preintervention and post-intervention (baseline; 10-weeks). Post-intervention, mean BMI and waist circumference decreased by 0.5 kg/m2 and 0.9 cm, while z-scores decreased by 0.20 and 0.20, respectively (p<0.0001). Improvements were found in children's psychological symptoms (-1.6 units, p<0.0001), parent self-efficacy (p<0.0001), physical activity (+2.9 h/week, p<0.01), sedentary activities (-4.1 h/week, p<0.0001) and the proportion of parents and children eating five or more portions of fruit and vegetables per day (both p<0.0001). Attendance at the 10 sessions was 73% with a 70% retention rate. Conclusions: Participation in the MEND 5-7 programme was associated with beneficial changes in physical, behavioural and psychological outcomes for children with complete sets of measurement data, when implemented in UK community settings under service level conditions. Further investigation is warranted to establish if these findings are replicable under controlled conditions.
  • Short, frequent high-intensity physical activity breaks reduce appetite compared with a continuous moderate-intensity exercise bout

    Maylor, Benjamin David; Zakrzewski-Fruer, Julia K.; Orton, Charlie J.; Bailey, Daniel Paul; University of Bedfordshire; Leicester General Hospital; Brunel University London (2022-12-06)
    A single exercise session can affect appetite-regulating hormones and suppress appetite. The effects of short, regular physical activity breaks across the day on appetite are unclear. This study investigated the effects of breaking up sitting with high-intensity physical activity versus a single bout of moderate-intensity exercise and prolonged sitting on appetite control. In this randomised crossover trial, 14 sedentary, inactive adults (seven women) completed three, 8-h experimental conditions: 1) prolonged sitting (SIT); 2) 30-min of moderate-intensity exercise followed by prolonged sitting (EX-SIT), and 3) sitting with 2 min 32 s of high-intensity physical activity every hour (SIT-ACT). Physical activity energy expenditure was matched between EX-SIT and SIT-ACT. Subjective appetite was measured every 30-min with acylated ghrelin and total peptide-YY (PYY) measured hourly in response to two standardised test meals. An ad libitum buffet meal was provided at the end of each condition. Based on linear mixed model analysis, total area under the curve for satisfaction was 16% higher (p=0.021) and overall appetite was 11% lower during SIT-ACT versus EX-SIT (p=0.018), with no differences between SIT-ACT and SIT. Time series analysis indicated that SIT-ACT reduced subjective appetite during the majority of the post-lunch period compared with SIT and EX-SIT, with some of these effects reversed earlier in the afternoon (p<0.05). Total PYY and acylated ghrelin did not differ between conditions. Relative energy intake was 760 kJ lower during SIT-ACT versus SIT (p=0.024). High-intensity physical activity breaks may be effective in acutely suppressing appetite; yet, appetite-regulating hormones may not explain such responses.
  • What roles does physical activity play following the death of a parent as a young person? a qualitative investigation

    Williams, Jane; Howlett, Neil; Shorter, Gillian; Zakrzewski-Fruer, Julia K.; Chater, Angel M.; University of Bedfordshire; University of Hertfordshire; Queens University Belfast; University College London (Biomed Central, 2022-11-25)
    Background: Physical activity benefits physical and mental health. However, limited research investigates if physical activity can improve outcomes from the grieving process following the death of a parent. Methods: Semi-structured interviews were conducted with 14 individuals (n = 8 female; age M = 31.2 years), who had experienced the death of a parent when they were aged between 10-24 years old, using retrospective recall. Data were analysed inductively using thematic analysis. Results: Six themes were identified. Physical activity was seen as; 1) ‘Therapeutic’; providing an 2) ‘Emotional Outlet’ and created a strong sense of 3) ‘Social Support’. Alongside it 4) ‘Builds Confidence’, and led to 5) ‘Finding Yourself’ and 6) ‘Improved Health’ (physical and psychological). Conclusion: Physical activity has the potential to provide positive experiences following a parental bereavement. It can provide a sense of freedom and was seen to alleviate grief outcomes, build resilience, enable social support and create a stronger sense of self. Bereavement support services for young people who have experienced death of a parent should consider physical activity as a viable intervention to support the grieving process. Keywords: Physical Activity, Exercise, Parental Bereavement, Death, Grief, Social Support, Resilience
  • Co-benefits of physical activity: assisting cardiometabolic disease prevention and climate change mitigation by active travel to school

    Zakrzewski-Fruer, Julia K.; University of Bedfordshire (2022-08-22)
    With many children and adolescents at risk of developing cardiometabolic disease (e.g. type 2 diabetes, cardiovascular disease) due to their low physical activity levels (Steene-Johannessen et al., 2020) and global concerns of climate change placing uncertainty on their futures (Gasparri et al., 2022), research on the co-benefits of physical activity for human and planetary health is highly topical and of interest to these young populations. A recent harmonised analysis (n=47,497) reported that around two-thirds of European children and adolescents aged 2–18 years are not sufficiently active, defined as less than an average of 60 min of moderate-to-vigorous physical activity per day (WHO, 2020), when measured objectively, with higher inactivity in girls versus boys and with increasing age (Steene-Johannessen et al., 2020). Targeting young people to aid disease prevention rather than focusing efforts towards treatment in later life may also be of planetary benefit due to reduced greenhouse gas emissions associated with disease either directly via, for example, blood analysis consumables, drug manufacturing and clinical waste disposal associated with diagnosis and treatment, or indirectly via disease effects on lifestyle, among other things (Eckelman et al., 2018).
  • Health relevance of lowering postprandial glycaemia in the paediatric population through diet - results from a multistakeholder workshop

    Vinoy, Sophie; Goletzke, Janina; Rakhshandehroo, Maryam; Schweitzer, Lisa; Flourakis, Matthieu; Körner, Antje; Alexy, Ute; van Schothorst, Evert M.; Ceriello, Antonio; Zakrzewski-Fruer, Julia K.; et al. (2022-11-15)
    To summarise current knowledge and gaps regarding the role of postprandial glycaemic response in the paediatric population, a workshop was organized in June 2021 by the European branch of the International Life Science Institute (ILSI). This virtual event comprised of talks given by experts followed by in-depth discussions in breakout sessions with workshop participants. The main pre-specified topics addressed by the workshop organising committee to the invited speakers and the workshop participants were: 1) the role of glycaemic responses for paediatric health, based on mechanistic insights from animal and human data, and long-term evidence from observational and intervention studies in paediatric populations, and 2) changes in metabolism and changes in dietary needs from infancy to adolescence. Each talk as well as the discussions were summarised, including the main identified research gaps. The workshop led to the consensus on the crucial role on health of postprandial glycaemic response in paediatric population. However, a lack of scientific data has been identified regarding detailed glucose and insulin profiles in response to foods commonly consumed by paediatric populations, as well as a lack of long-term evidence including the need for suitable predictors during childhood and adolescence to anticipate health effects during adulthood.
  • Enhancing cardiometabolic health through physical activity and breakfast manipulations in children and adolescents: good for humans, good for the planet

    Zakrzewski-Fruer, Julia K.; Thackray, Alice E.; University of Bedfordshire; Loughborough University; University Hospitals of Leicester NHS Trust and University of Leicester (2022-11-11)
    The human health benefits of cardiometabolic disease prevention can be accompanied by planetary co-benefits. Focusing efforts towards young people, including children and adolescents, is conducive to disease prevention. In the context of cardiometabolic disease prevention, this review paper critically summarises the available literature on the acute cardiometabolic responses to physical activity and breakfast manipulations among young people. Given the seriousness of global climate change, which will disproportionally affect our younger generations, the paper offers new insights into the inherent interactions between child-adolescent behaviour and cardiometabolic health from an environmental sustainability perspective to aid climate change mitigation efforts, including exploring future research avenues. A growing evidence base suggests acute moderate- to high-intensity exercise bouts can attenuate postprandial plasma glucose, insulin and triacylglycerol concentrations for up to 24–48 h in young people. Whether accumulating physical activity throughout the day with short, frequent bouts promotes cardiometabolic risk marker attenuations is unclear. Breakfast consumption may enhance free-living physical activity and reduce glycaemic responses to subsequent meals for a possible additive impact. If repeated habitually, attenuations in these cardiometabolic risk factors would be conducive to disease prevention, reducing the greenhouse gas emissions associated with disease diagnosis and treatment. To progress current understanding with high public health and planetary relevance, research among samples of ‘at risk’ young people that span cellular-level responses to ecologically valid settings and address human and planetary health co-benefits is needed. Indeed, certain physical activity opportunities, such as active travel to school, offer important direct co-benefits to human and planetary health.

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