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Patterns of energy allocation during energetic scarcity; evolutionary insights from ultra-endurance events.
Longman, DP, Dolan, E, Wells, JCK, Stock, JT
Comparative biochemistry and physiology. Part A, Molecular & integrative physiology. 2023;:111422
Abstract
Exercise physiologists and evolutionary biologists share a research interest in determining patterns of energy allocation during times of acute or chronic energetic scarcity. Within sport and exercise science, this information has important implications for athlete health and performance. For evolutionary biologists, this would shed new light on our adaptive capabilities as a phenotypically plastic species. In recent years, evolutionary biologists have begun recruiting athletes as study participants and using contemporary sports as a model for studying evolution. This approach, known as human athletic palaeobiology, has identified ultra-endurance events as a valuable experimental model to investigate patterns of energy allocation during conditions of elevated energy demand, which are generally accompanied by an energy deficit. This energetic stress provokes detectable functional trade-offs in energy allocation between physiological processes. Early results from this modelsuggest thatlimited resources are preferentially allocated to processes which could be considered to confer the greatest immediate survival advantage (including immune and cognitive function). This aligns with evolutionary perspectives regarding energetic trade-offs during periods of acute and chronic energetic scarcity. Here, we discuss energy allocation patterns during periods of energetic stress as an area of shared interest between exercise physiology and evolutionary biology. We propose that, by addressing the ultimate "why" questions, namely why certain traits were selected for during the human evolutionary journey, an evolutionary perspective can complement the exercise physiology literature and provide a deeper insight of the reasons underpinning the body's physiological response to conditions of energetic stress.
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The Influence of n-3PUFA Supplementation on Muscle Strength, Mass, and Function: A Systematic Review and Meta-Analysis.
Santo André, HC, Esteves, GP, Barreto, GHC, Longhini, F, Dolan, E, Benatti, FB
Advances in nutrition (Bethesda, Md.). 2023;14(1):115-127
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Plain language summary
Omega 3 polyunsaturated fatty acids (n-3PUFA) are long-chain polyunsaturated fatty acids essential to human health. They play a role in cell membrane integrity, immune and inflammation regulation, cognition and neuromuscular function. As the human body cannot make these fatty acids, they need to be obtained through diet or supplementation. Regarding skeletal muscle, recent research showed that n-3PUFAs may increase the uptake of amino acids by increasing the membrane fluidity in the muscle, and by activating pathways that inhibit protein breakdown. This led to the hypothesis that n-3PUFAs may enhance muscle mass gain and strength. This systematic review sought to gather all available evidence about the impact of n-3PUFA supplementation on muscle mass, strength, and function in healthy young and older adults. The review included 14 studies with a total of 1443 participants. The authors found that n-3PUFA supplementation had no significant effect on muscle mass or muscle function in healthy young and older adults, however, a very small but significant positive effect was noted regarding muscle strength. In the discussion section, the authors explain the challenges of their review and how these findings integrate with the current understanding and other research findings. They concluded more research is needed to get a better insight into the effects of n-3PUFA on muscle function and the variants.
Abstract
The effects of omega 3 polyunsaturated fatty acids (n-3PUFA) supplementation on skeletal muscle are currently unclear. The purpose of this systematic review was to synthesize all available evidence regarding the influence of n-3PUFA supplementation on muscle mass, strength, and function in healthy young and older adults. Four databases were searched (Medline, Embase, Cochrane CENTRAL, and SportDiscus). Predefined eligibility criteria were determined according to Population, Intervention, Comparator, Outcomes, and Study Design. Only peer-reviewed studies were included. The Cochrane RoB2 Tool and the NutriGrade approach were used to access risk of bias and certainty in evidence. Effect sizes were calculated using pre-post scores and analyzed using a three-level, random-effects meta-analysis. When sufficient studies were available, subanalyses were performed in the muscle mass, strength, and function outcomes according to participant's age (<60 or ≥60 years), supplementation dosage (<2 or ≥2 g/day), and training intervention ("resistance training" vs. "none or other"). Overall, 14 individual studies were included, total 1443 participants (913 females; 520 males) and 52 outcomes measures. Studies had high overall risk of bias and consideration of all NutriGrade elements resulted in a certainty assessment of moderate meta-evidence for all outcomes. n-3PUFA supplementation had no significant effect on muscle mass (standard mean difference [SMD] = 0.07 [95% CI: -0.02, 0.17], P = 0.11) and muscle function (SMD = 0.03 [95% CI: -0.09, 0.15], P = 0.58), but it showed a very small albeit significant positive effect on muscle strength (SMD = 0.12 [95% CI: 0.006, 0.24], P = 0.04) in participants when compared with placebo. Subgroup analyses showed that age, supplementation dose, or cosupplementation alongside resistance training did not influence these responses. In conclusion, our analyses indicated that n-3PUFA supplementation may lead to very small increases in muscle strength but did not impact muscle mass and function in healthy young and older adults. To our knowledge, this is the first review and meta-analysis investigating whether n-3PUFA supplementation can lead to increases in muscle strength, mass, and function in healthy adults. Registered protocol: doi.org/10.17605/OSF.IO/2FWQT.
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P1NP and β-CTX-1 Responses to a Prolonged, Continuous Running Bout in Young Healthy Adult Males: A Systematic Review with Individual Participant Data Meta-analysis.
Civil, R, Dolan, E, Swinton, PA, Santos, L, Varley, I, Atherton, PJ, Elliott-Sale, KJ, Sale, C
Sports medicine - open. 2023;(1):85
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BACKGROUND Circulating biomarkers of bone formation and resorption are widely used in exercise metabolism research, but their responses to exercise are not clear. This study aimed to quantify group responses and inter-individual variability of P1NP and β-CTX-1 after prolonged, continuous running (60-120 min at 65-75% V̇O2max) in young healthy adult males using individual participant data (IPD) meta-analysis. METHODS The protocol was designed following PRISMA-IPD guidelines and was pre-registered on the Open Science Framework prior to implementation ( https://osf.io/y69nd ). Changes in P1NP and β-CTX-1 relative to baseline were measured during, immediately after, and in the hours and days following exercise. Typical hourly and daily variations were estimated from P1NP and β-CTX-1 changes relative to baseline in non-exercise (control) conditions. Group responses and inter-individual variability were quantified with estimates of the mean and standard deviation of the difference, and the proportion of participants exhibiting an increased response. Models were conducted within a Bayesian framework with random intercepts to account for systematic variation across studies. RESULTS P1NP levels increased during and immediately after running, when the proportion of response was close to 100% (75% CrI: 99 to 100%). P1NP levels returned to baseline levels within 1 h and over the next 4 days, showing comparable mean and standard deviation of the difference with typical hourly (0.1 ± 7.6 ng·mL-1) and daily (- 0.4 ± 5.7 ng·mL-1) variation values. β-CTX-1 levels decreased during and up to 4 h after running with distributions comparable to typical hourly variation (- 0.13 ± 0.11 ng·mL-1). There was no evidence of changes in β-CTX-1 levels during the 4 days after the running bout, when distributions were also similar between the running data and typical daily variation (- 0.03 ± 0.10 ng·mL-1). CONCLUSION Transient increases in P1NP were likely biological artefacts (e.g., connective tissue leakage) and not reflective of bone formation. Comparable small decreases in β-CTX-1 identified in both control and running data, suggested that these changes were due to the markers' circadian rhythm and not the running intervention. Hence, prolonged continuous treadmill running did not elicit bone responses, as determined by P1NP and β-CTX-1, in this population.
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Sodium bicarbonate induces alkalosis, but improves high-intensity cycling performance only when participants expect a beneficial effect: a placebo and nocebo study.
Zagatto, AM, Lopes, VHF, Dutra, YM, de Poli, RAB, Dolan, E, Rasica, L, Murias, JM, de Azevedo, PHSM
European journal of applied physiology. 2023
Abstract
The study aimed to investigate the effects of sodium bicarbonate (NaHCO3) intake with divergent verbal and visual information on constant load cycling time-to-task failure, conducted within the severe intensity domain. Fifteen recreational cyclists participated in a randomized double-blind, crossover study, ingesting NaHCO3 or placebo (i.e., dextrose), but with divergent information about its likely influence (i.e., likely to induce ergogenic, inert, or harmful effects). Performance was evaluated using constant load cycling time to task failure trial at 115% of peak power output estimated during a ramp incremental exercise test. Data on blood lactate, blood acid-base balance, muscle electrical activity (EMG) through electromyography signal, and the twitch interpolation technique to assess neuromuscular indices were collected. Despite reduced peak force in the isometric maximal voluntary contraction and post-effort peripheral fatigue in all conditions (P < 0.001), neither time to task failure, EMG nor, blood acid-base balance differed between conditions (P > 0.05). Evaluation of effect sizes of all conditions suggested that informing participants that the supplement would be likely to have a positive effect (NaHCO3/Ergogenic: 0.46; 0.15-0.74; Dextrose/Ergogenic: 0.45; 0.04-0.88) resulted in improved performance compared to control. Thus, NaHCO3 ingestion consistently induced alkalosis, indicating that the physiological conditions to improve performance were present. Despite this, NaHCO3 ingestion did not influence performance or indicators of neuromuscular fatigue. In contrast, effect size estimates indicate that participants performed better when informed that they were ingesting an ergogenic supplement. These findings suggest that the apparently ergogenic effect of NaHCO3 may be due, at least in part, to a placebo effect.
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Beta-alanine did not improve high-intensity performance throughout simulated road cycling.
Perim, P, Gobbi, N, Duarte, B, Oliveira, LF, Costa, LAR, Sale, C, Gualano, B, Dolan, E, Saunders, B
European journal of sport science. 2022;(8):1240-1249
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This study investigated the effect of beta-alanine supplementation on short-duration sprints and final 4-km simulated uphill cycling time-trial performance during a comprehensive and novel exercise protocol representative of the demands of road-race cycling, and determined if changes were related to increases in muscle carnosine content. Seventeen cyclists (age 38 ± 9 y, height 1.76 ± 0.07 m, body mass 71.4 ± 8.8 kg, V̇O2max 52.4 ± 8.3 ml·kg-1·min-1) participated in this placebo-controlled, double-blind study. Cyclists undertook a prolonged intermittent cycling protocol lasting 125 min, with a 10-s sprint every 20 min, finishing with a 4-km time-trial at 5% simulated incline. Participants completed two familiarization sessions, and two main sessions, one pre-supplementation and one post-supplementation following 28 days of 6.4 g·day-1 of beta-alanine (N=11) or placebo (N=6; maltodextrin). Muscle biopsies obtained pre- and post-supplementation were analysed for muscle carnosine content. There were no main effects on sprint performance throughout the intermittent cycling test (all P>0.05). There was no group (P=0.69), time (P=0.50) or group x time interaction (P=0.26) on time-to-complete the 4-km time-trial. Time-to-completion did not change from pre- to post-supplementation for BA (-19.2 ± 45.6 s, P=0.43) or PL (+2.8 ± 31.6 s, P=0.99). Beta-alanine supplementation increased muscle carnosine content from pre- to post-supplementation (+9.4 ± 4.0 mmol·kg-1dm; P<0.0001) but was not related to performance changes (r=0.320, P=0.37). Chronic beta-alanine supplementation increased muscle carnosine content but did not improve short-duration sprint performance throughout simulated road race cycling, nor 4-km uphill time-trial performance conducted at the end of this cycling test.HighlightsPerformance during prolonged cycling events often depends on the ability to maintain an increased power output during higher intensity periods. Thus, cyclists are likely heavily dependent on their ability to resist fatigue during these periods of high-intensity activity.Meta-analytical data show beta-alanine to be an effective supplement to improve exercise outcomes, but little work exists on its efficacy during dynamic actions that are common during prolonged cycling.Beta-alanine supplementation increased muscle carnosine content but did not generate improvements in the performance of high-intensity cycling (10-s sprints or 4-km uphill time-trial) during a simulated road race cycling protocol.These data suggest that short duration sprints (≤10 s) and longer duration (>10 min) high-intensity activity throughout endurance cycling may not be improved with beta-alanine supplementation despite increases in muscle carnosine content.
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A Life History Perspective on Athletes with Low Energy Availability.
Shirley, MK, Longman, DP, Elliott-Sale, KJ, Hackney, AC, Sale, C, Dolan, E
Sports medicine (Auckland, N.Z.). 2022;(6):1223-1234
Abstract
The energy costs of athletic training can be substantial, and deficits arising from costs unmet by adequate energy intake, leading to a state of low energy availability, may adversely impact athlete health and performance. Life history theory is a branch of evolutionary theory that recognizes that the way the body uses energy-and responds to low energy availability-is an evolved trait. Energy is a finite resource that must be distributed throughout the body to simultaneously fuel all biological processes. When energy availability is low, insufficient energy may be available to equally support all processes. As energy used for one function cannot be used for others, energetic "trade-offs" will arise. Biological processes offering the greatest immediate survival value will be protected, even if this results in energy being diverted away from others, potentially leading to their downregulation. Athletes with low energy availability provide a useful model for anthropologists investigating the biological trade-offs that occur when energy is scarce, while the broader conceptual framework provided by life history theory may be useful to sport and exercise researchers who investigate the influence of low energy availability on athlete health and performance. The goals of this review are: (1) to describe the core tenets of life history theory; (2) consider trade-offs that might occur in athletes with low energy availability in the context of four broad biological areas: reproduction, somatic maintenance, growth, and immunity; and (3) use this evolutionary perspective to consider potential directions for future research.
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Acute and post-acute COVID-19 presentations in athletes: a systematic review and meta-analysis.
Lemes, IR, Smaira, FI, Ribeiro, WJD, Favero, NK, Matos, LDNJ, Pinto, ALS, Dolan, E, Gualano, B, ,
British journal of sports medicine. 2022;(16):941-947
Abstract
OBJECTIVE To describe acute/postacute COVID-19 presentations in athletes. DESIGN Systematic review and meta-analysis. DATA SOURCES The search was conducted in four databases (MEDLINE, EMBASE, SCOPUS, SPORTDiscus) and restricted to studies published from 2019 to 6 January 2022. ELIGIBILITY CRITERIA FOR SELECTING STUDIES Studies were required to (1) include professional, amateur or collegiate/university athletes with COVID-19; (2) present data on acute/postacute COVID-19 symptoms and (3) have an observational design. Risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal tools. RESULTS 43 studies with 11 518 athletes were included. For acute presentation, the pooled event rates for asymptomatic and severe COVID-19 were 25.5% (95% CI: 21.1% to 30.5%) and 1.3% (95% CI: 0.7% to 2.3%), respectively. For postacute presentations, the pooled estimate of persistent symptoms was 8.3% (95% CI: 3.8% to 17.0%). Pooled estimate for myocardial involvement was 5.0% (95% CI: 2.5% to 9.8%) in athletes undergoing any cardiac testing, and 2.5% (95% CI: 1.0% to 5.8%) in athletes undergoing MRI, although clinical symptoms were not characterised. None of the studies with a control group (eg, non-infected athletes) could confirm a causal relationship between COVID-19 and myocardial involvement. CONCLUSION This broad characterisation of COVID-19 presentations in athletes indicates that ~94% exhibited mild or no acute symptoms. The available evidence did not confirm a causal relationship between COVID-19 and myocardial involvement. A small proportion of athletes experienced persistent symptoms while recovering from infection, which were mostly mild in nature, but could affect return-to-play decisions and timing.
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Sodium bicarbonate supplementation and the female athlete: A brief commentary with small scale systematic review and meta-analysis.
Saunders, B, Oliveira, LF, Dolan, E, Durkalec-Michalski, K, McNaughton, L, Artioli, GG, Swinton, PA
European journal of sport science. 2022;(5):745-754
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ABSTRACTSodium bicarbonate (SB) is considered an effective ergogenic supplement for improving high-intensity exercise capacity and performance, although recent data suggests that women may be less amenable to its ergogenic effects than men. Currently, an apparent paucity of data on women means no consensus exists on whether women benefit from SB supplementation. The aim of the current study was to quantify the proportion of the published literature on SB supplementation that includes women, and to synthesise the evidence regarding its effects on blood bicarbonate and exercise performance in women by performing a systematic review and meta-analysis. Electronic searches of the literature were undertaken using three databases (MEDLINE, Embase, SPORTDiscus) to identify relevant articles. All meta-analyses were performed within a Bayesian framework. A total of 149 SB articles were identified, 11 of which contained individual group data for women. Results indicated a pooled blood bicarbonate increase of 7.4 [95%CrI: 4.2-10.4 mmol·L-1] following supplementation and a pooled standardised exercise effect size of 0.37 [95%CrI: -0.06-0.92]. The SB literature is skewed, with only 20% (30 studies) of studies employing female participants, of which only 11 studies (7.4%) provided group analyses exclusively in women. Despite the small amount of available data, results are consistent in showing that SB supplementation in women leads to large changes in blood bicarbonate and that there is strong evidence for a positive ergogenic effect on exercise performance that is likely to be small to medium in magnitude.HighlightsThis study aimed to quantify the proportion of the published literature on sodium bicarbonate supplementation that includes women and to synthesise the evidence regarding its ergogenic effect on women, using a systematic review and meta-analytic approach.The sodium bicarbonate literature is skewed, with only 30 studies (20%) employing female participants, of which only 11 studies (7.4%) provided group analyses exclusively in women.Despite the small amount of available data, results are consistent in showing that sodium bicarbonate supplementation in women leads to large changes in blood bicarbonate and that there is strong evidence for a positive ergogenic effect on exercise performance that is likely small to medium in magnitude.Based on these findings, we do not believe there is any evidence to support sex-specific sodium bicarbonate dosing recommendations and that current recommendations of 0.2-0.3 g·kg-1BM of SB taken 60-180 min prior to high-intensity exercise appear appropriate for the female athlete.
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The Bone Biomarker Response to an Acute Bout of Exercise: A Systematic Review with Meta-Analysis.
Dolan, E, Dumas, A, Keane, KM, Bestetti, G, Freitas, LHM, Gualano, B, Kohrt, WM, Kelley, GA, Pereira, RMR, Sale, C, et al
Sports medicine (Auckland, N.Z.). 2022;(12):2889-2908
Abstract
BACKGROUND Circulating biomarkers are often used to investigate the bone response to an acute bout of exercise, but heterogeneity in factors such as study design, quality, selected biomarkers, and exercise and participant characteristics render it difficult to synthesize and evaluate available evidence. OBJECTIVE The aim of this study was to quantify the effects of an acute exercise bout on bone biomarkers, along with the influence of potential moderators such as participant, exercise, and design characteristics, using a systematic review and meta-analytic approach. METHODS The protocol was designed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) guidelines and prospectively published. Seven databases were systematically searched in accordance with predefined eligibility criteria. Bayesian three-level hierarchical meta-analysis models were used to explore the main effects of acute exercise on bone biomarkers, as well as potential moderating factors. Modelled effect sizes were interpreted according to three metrics, namely (1) evidence of an effect (defined by whether, or how much of, the credible interval [CrI] included zero); (b) the size of that effect (threshold values of 0.01, 0.2, 0.5 and 0.8 were used to describe effect sizes as very small, small, medium and large, respectively); and (c) the level of certainty in the estimated effect (defined using the GRADE framework). RESULTS Pooling of outcomes across all designs and categories indicated that an acute bout of exercise increased bone resorption (ES0.5 0.10, 95% CrI 0.00-0.20) and formation (ES0.5 0.05, 95% CrI 0.01-0.08) markers but the effects were very small and highly variable. Furthermore, moderator analyses revealed the source of some of this variability and indicated that exercise type and impact loading influenced the bone resorptive response. A moderate increase in C-terminal telopeptide of type 1 collagen (CTX-1) was observed in response to cycling (ES0.5 0.65, 95% CrI 0.20-0.99), with greater durations and more work leading to larger CTX-1 increases. CTX-1 response peaked within 15 min and 2 h after the exercise bout. Other exercise types did not influence CTX-1. Changes to all bone formation markers were very small and transient, with the very small increases returning to baseline within 15 min of exercise cessation. No major trends for bone formation markers were identified across any of the moderating categories investigated. Certainty of evidence in most outcomes was deemed to be low or very low. CONCLUSION The large influence of an acute bout of prolonged cycling on the bone resorption marker CTX-1, alongside the lack of a response of any biomarker to resistance or high-impact exercise types, indicate that these biomarkers may be more useful at investigating potentially osteolytic aspects of exercise, and raises questions about their suitability to investigate the osteogenic potential of different exercise types, at least in the short term and in response to a single exercise bout. Certainty in all outcomes was low or very low, due to factors including risk of bias, lack of non-exercise controls, inconsistency, imprecision and small-study effects. PROTOCOL REGISTRATION AND PUBLICATION This investigation was prospectively registered on the Open Science Framework Registry ( https://osf.io/6f8dz ) and the full protocol underwent peer review prior to conducting the investigation.
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Extracellular Buffering Supplements to Improve Exercise Capacity and Performance: A Comprehensive Systematic Review and Meta-analysis.
de Oliveira, LF, Dolan, E, Swinton, PA, Durkalec-Michalski, K, Artioli, GG, McNaughton, LR, Saunders, B
Sports medicine (Auckland, N.Z.). 2022;(3):505-526
Abstract
BACKGROUND Extracellular buffering supplements [sodium bicarbonate (SB), sodium citrate (SC), sodium/calcium lactate (SL/CL)] are ergogenic supplements, although questions remain about factors which may modify their effect. OBJECTIVE To quantify the main effect of extracellular buffering agents on exercise outcomes, and to investigate the influence of potential moderators on this effect using a systematic review and meta-analytic approach. METHODS This study was designed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Three databases were searched for articles that were screened according to inclusion/exclusion criteria. Bayesian hierarchical meta-analysis and meta-regression models were used to investigate pooled effects of supplementation and moderating effects of a range of factors on exercise and biomarker responses. RESULTS 189 articles with 2019 participants were included, 158 involving SB supplementation, 30 with SC, and seven with CL/SL; four studies provided a combination of buffering supplements together. Supplementation led to a mean estimated increase in blood bicarbonate of + 5.2 mmol L-1 (95% credible interval (CrI) 4.7-5.7). The meta-analysis models identified a positive overall effect of supplementation on exercise capacity and performance compared to placebo [ES0.5 = 0.17 (95% CrI 0.12-0.21)] with potential moderating effects of exercise type and duration, training status and when the exercise test was performed following prior exercise. The greatest ergogenic effects were shown for exercise durations of 0.5-10 min [ES0.5 = 0.18 (0.13-0.24)] and > 10 min [ES0.5 = 0.22 (0.10-0.33)]. Evidence of greater effects on exercise were obtained when blood bicarbonate increases were medium (4-6 mmol L-1) and large (> 6 mmol L-1) compared with small (≤ 4 mmol L-1) [βSmall:Medium = 0.16 (95% CrI 0.02-0.32), βSmall:Large = 0.13 (95% CrI - 0.03 to 0.29)]. SB (192 outcomes) was more effective for performance compared to SC (39 outcomes) [βSC:SB = 0.10 (95% CrI - 0.02 to 0.22)]. CONCLUSIONS Extracellular buffering supplements generate large increases in blood bicarbonate concentration leading to positive overall effects on exercise, with sodium bicarbonate being most effective. Evidence for several group-level moderating factors were identified. These data can guide an athlete's decision as to whether supplementation with buffering agents might be beneficial for their specific aims.