Browsing by Author "Barnes M"

Now showing 1 - 9 of 9
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    An experimental model of contusion injury in humans
    (Public Library of Science, 17/11/2022) Barnes M; Lomiwes D; Parry DAD; Stephen M
    Introduction Contusion injuries are common in sport, but our knowledge of the responses to injury primarily come from animal studies and research using eccentric exercise. Therefore, the aim of this study was to develop a model of contusion injury in human participants and, additionally, investigate and compare physiological responses to four impact loads. Methods Thirty-two males were exposed to a single impact of either 4.2, 5.2, 6.2 or 7.2kg, dropped from 67 cm, on to the vastus lateralis of one leg. Maximum voluntary and electrically induced quadriceps force, and pressure pain threshold were measured, and blood sampling carried out, prior to and 30min, 24, 48 and 72h post-impact. Magnetic resonance imaging was carried out 24h post-impact to quantify oedema. Results Despite impact force with 7.2kg (1681.4 ± 235.6 N) not being different to 6.2kg (1690.7 ± 117.6 N), 7.2kg resulted in greater volume of oedema, voluntary force loss, pain and elevations in creatine kinase than the other loads. Although electrically induced force changed over time, post-hoc analysis failed to identify any changes. Interleukin-6 and prostaglandin-E2 did not change over time for any of the loads. Significant correlations were found between oedema volume, pressure pain threshold and maximum voluntary contraction force. Conclusions This is the first experimental study to investigate traumatic loading of skeletal muscle and the subsequent physiological responses associated with contusion injuries in humans. The absence of immediate elevations in creatine kinase and changes in electrically induced force suggest impact, with forces similar to those experienced in contact sport, does not cause significant, direct damage to skeletal muscle. However, the relationship between oedema volume, changes in pressure pain threshold and maximum voluntary contraction force suggests central inhibition plays a role in contusion-related muscle dysfunction.
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    Characterising the Cytokine and Circulating Immune Cell Response After a Single Bout of Eccentric Stepping Exercise in Healthy Untrained Males
    (Springer Nature, 2023-05-15) Lomiwes D; Barnes M; Shaw O; Ngametua N; Sawyer GM; Burr NS; Miller MR
    Purpose The mechanisms that underpin exercise-induced muscle damage and recovery are believed to be mediated, in part, by immune cells recruited to the site of injury. The aim of this study was to characterise the effects of muscle damage from bench-stepping on circulating cytokine and immune cell populations post-exercise and during recovery. Methods Ten untrained, healthy male volunteers completed 30 min of bench-stepping exercise to induce muscle damage to the eccentrically exercised leg. Muscle function, muscle pain and soreness were measured before, immediately after and 24, 48 and 72 h after exercise. Plasma creatine kinase, cartilage oligomeric matrix protein, cytokines and circulating immune cell phenotyping were also measured at these timepoints. Results Significant decreases occurred in eccentric, isometric and concentric (P = 0.018, 0.047 and 0.003, respectively) muscle function in eccentrically, but not concentrically, exercised quadriceps post-exercise. Plasma monocyte chemoattractant protein (MCP)-1 concentrations significantly increased immediately after exercise (69.0 ± 5.8 to 89.5 ± 10.0 pg/mL), then declined to below pre-exercise concentrations (58.8 ± 6.3 pg/mL) 72 h after exercise. These changes corresponded with the significant decrease of circulating CD45+ CD16− CD14+ monocytes (5.8% ± 1.5% to 1.9% ± 0.5%; Pre-exercise vs. 48 h) and increase of CD45+ CD3+ CD56− T-cells (60.5% ± 2.2% to 66.1% ± 2.1%; Pre-exercise vs. 72 h) during recovery. Conclusion Bench-stepping induced muscle damage to the quadriceps, which mediated systemic changes in MCP-1, monocytes and T-cells immediately post-exercise and during recovery. Further research is needed to clarify how modulations in immune subpopulations facilitate muscle recovery and adaptation following muscle damage.
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    Chronic carbohydrate restriction improves endurance capacity and body composition in men and women
    (Cycling Research Center, 2022-06-06) O'Connor W; O'Connor E; Barnes M; Miller M; Gardener H; Stannard S; Zabala M
    This study was designed to test whether adaptation to a CHO-restricted diet affects physical capacity during prolonged exercise. It is hypothesised that chronically reducing an individual’s dietary carbohydrate intake during training will increase their maximal rate of fatty acid oxidation during subsequent exercise compared to a chronic high carbohydrate diet. Thirteen highly trained endurance athletes (eight males, VO2max 66.0 ± 9.5 ml/kg/min, five females VO2max 50.6 ± 8.4 ml/kg/min) consumed a high (>5 g CHO/kg/day) or low (<2 g CHO/kg/day) carbohydrate training diet for four weeks in a randomized cross-over design. Performance was measured after a 24 h high carbohydrate “loading” regime, through a self-paced time trial to complete a fixed workload equivalent to five hours at a workload calculated to elicit 55% VO2max. Although time to completion was not significantly different between diets, the average absolute (watts) and relative (W/kg) power outputs were significantly better on the carbohydrate restricted diet (p = 0.03 and 0.02 respectively). Both sexes responded similarly in terms of performance whilst only women significantly improved body composition when carbohydrate was restricted (p = 0.02). Results from this study highlight that when carbohydrate is restricted during training, trained endurance athletes show improved ultra-endurance performance relative to their body mass.
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    Editorial: Nutrition and muscle recovery after exercise
    (Frontiers Media S.A., 2024-04-23) Cornish SM; Barnes M
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    Emerging transitions in organic waste infrastructure in Aotearoa New Zealand
    (John Wiley and Sons, Inc., 2023-04-01) Diprose G; Dombroski K; Sharp E; Yates A; Peryman B; Barnes M
    Aotearoa New Zealand is at a critical juncture in reducing and managing organic waste. Research has highlighted the significant proportion of organic waste sent to landfills and associated adverse effects such as greenhouse gas emissions and loss of valuable organic matter. There is current debate about what practices and infrastructure to invest in to better manage and use organic waste. We highlight the diversity of existing organic waste practices and infrastructures, focusing on Auckland, Wellington and Christchurch. We show how debates about organic waste practices and infrastructure connect across three themes: waste subjectivities, collective action in place and language.
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    Incidence of Match Injuries in an Amateur Women’s Rugby Union Team in New Zealand over Two Consecutive Seasons
    (Kosmos Publishers, 28/08/2020) King D; Hume PA; Clark TN; Foskett A; Barnes M
    Background: Rugby Union is played in over 200 countries with over 8.5 million registered players worldwide. Despite increased popularity of the game for women, there is relatively little evidence for incidence, causes or severity of injuries that occur during match participation. Purpose: To determine whether amateur women’s rugby union teams in New Zealand need injury prevention support, by providing evidence as to the incidence, causes and severity of injuries that occur during match participation. Study design: Descriptive epidemiological observational study. Methods: Epidemiology analysis to describe the incidence of match injuries in an amateur women’s rugby union team in New Zealand, over two consecutive seasons. Injury burden was calculated for all injuries by: injury region, reported as frequency of injuries by region; number of days lost; and mean number of days lost, with standard deviation. Results: Over the study, 138 injuries were recorded resulting in an injury incidence of 247.0 per 1,000 match-hrs. A total of 57 resulted in a time-loss injury incidence of 102.0 per 1,000 match-hrs. The hooker recorded a significantly lower mean (4.1 ±2.8 days) injury burden than the blind-side flanker (t(6)=-2.8; p=0.0314), center (t(6)=-2.8; p=0.0313) and fullback (t(6)=-2.7; p=0.0351) for total injuries. Discussion: The principal findings of this study were: (1) total injury incidence was 247.0 per 1,000 match-hrs; (2) time-lost from rugby due to injuries was 102.0 per 1,000 match-hrs; (3) the lower limb sustained the highest injury incidence with the knee having the greatest proportion of these injuries; (4) the tackle recorded the highest injury rate, and being tackled was associated with a notably higher injury incidence than any other match event; (5) sprains and strains recorded the highest injury incidence; and (6) the lower limb body region recorded the most days lost and had the highest mean days lost per injury.
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    Nutrition-Based Strategies to Reduce Exercise-Induced Muscle Damage and Soreness
    (MDPI (Basel, Switzerland), 2023-05-29) Barnes M
    Exercise induced-muscle damage (EIMD) occurs after strenuous and/or novel exercise that involves repeated eccentric contractions [...].
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    Nutritional Compounds to Improve Post-Exercise Recovery
    (MDPI (Basel, Switzerland), 2022-12) O'Connor E; Mundel T; Barnes M
    The metabolic and mechanical stresses associated with muscle-fatiguing exercise result in perturbations to bodily tissues that lead to exercise-induced muscle damage (EIMD), a state of fatigue involving oxidative stress and inflammation that is accompanied by muscle weakness, pain and a reduced ability to perform subsequent training sessions or competitions. This review collates evidence from previous research on a wide range of nutritional compounds that have the potential to speed up post-exercise recovery. We show that of the numerous compounds investigated thus far, only two—tart cherry and omega-3 fatty acids—are supported by substantial research evidence. Further studies are required to clarify the potential effects of other compounds presented here, many of which have been used since ancient times to treat conditions associated with inflammation and disease.
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    The Efficacy of New Zealand Greenshell™ Mussel Powder Supplementation in Supporting Muscle Recovery Following Eccentric Exercise-Induced Muscle Damage in Healthy, Untrained Adult Males
    (MDPI (Basel, Switzerland), 2023-05-15) Lomiwes D; Barnes M; Shaw O; Ngametua N; Sawyer G; Burr N; Hedderley D; Kanon A; Bear T; Carroll A; Bentley_Hewitt K; Tian HS; Miller MR; Nieman DC
    Unaccustomed eccentric exercise results in muscle damage limiting physical performance for several days. This study investigated if Greenshell™ mussel (GSM) powder consumption expedited muscle recovery from eccentric exercise-induced muscle damage (EIMD). Methods: Twenty untrained adult men were recruited into a double-blind, placebo-controlled, cross-over study and were randomly assigned to receive the GSM powder or placebo treatment first. Participants consumed their allocated intervention for four weeks then completed a bench-stepping exercise that induced muscle damage to the eccentrically exercised leg. Muscle function, soreness and biomarkers of muscle damage, oxidative stress and inflammation were measured before exercise, immediately after exercise and 24, 48 and 72 h post exercise. GSM powder promoted muscle function recovery, significantly improving (p < 0.05) isometric and concentric peak torque at 48 h and 72 h post exercise, respectively. Participants on the GSM treatment had faster dissipation of soreness, with significant treatment × time interactions for affective (p = 0.007) and Visual Analogue Scale-assessed pain (p = 0.018). At 72 h, plasma creatine kinase concentrations in the GSM group were lower (p < 0.05) compared with the placebo group. This study provides evidence for GSM powder being effective in supporting muscle recovery from EIMD.