European Journal of Sport Science最新文献

{"title":"Mechanical power flow from trunk and lower limb joint power to external horizontal power in the track and field block start.","authors":"Natsuki Sado,&nbsp;Shinsuke Yoshioka,&nbsp;Senshi Fukashiro","doi":"10.1080/17461391.2022.2109067","DOIUrl":"10.1080/17461391.2022.2109067","url":null,"abstract":"<p><p>Sprint start performance is measured as the horizontal external power, the time-average rate of horizontal kinetic energy generation. Although joint powers have been examined, not all segment rotations on which positive powers are exerted necessarily contribute to forward propulsion; details regarding horizontal power remain unclear. Here we show the contributions of segment rotations to the forward and upward propulsion. We calculated the joint power exerted on each segment and the contributions from segment rotations to the normalised average horizontal and vertical external powers (<math><mover><msub><mrow><mrow><mover><mi>P</mi><mo>^</mo></mover></mrow></mrow><mrow><mrow><mi>hori</mi></mrow><mi>z</mi></mrow></msub><mo>¯</mo></mover></math> and <math><mover><msub><mrow><mrow><mover><mi>P</mi><mo>^</mo></mover></mrow></mrow><mrow><mrow><mi>vert</mi></mrow></mrow></msub><mo>¯</mo></mover></math>) during the sprint start by 12 male sprinters. Over half <math><mover><msub><mrow><mrow><mover><mi>P</mi><mo>^</mo></mover></mrow></mrow><mrow><mrow><mi>hori</mi></mrow><mi>z</mi></mrow></msub><mo>¯</mo></mover></math> (55 ± 6%) is due to the front thigh rotation (0.30 ± 0.04), on which the hip and knee exert positive power. Pelvic rotation does not contribute to <math><mover><msub><mrow><mrow><mover><mi>P</mi><mo>^</mo></mover></mrow></mrow><mrow><mrow><mi>hori</mi></mrow><mi>z</mi></mrow></msub><mo>¯</mo></mover></math> (0.00 ± 0.01). This highlights the importance of the hip-extensors strength and the need for it accompanied by the lumbar-extensors strength cancelling out the hip-extensors action on the pelvis and promoting hip-extensor-induced thigh rotation. The front thigh rotation decreases <math><mover><msub><mrow><mrow><mover><mi>P</mi><mo>^</mo></mover></mrow></mrow><mrow><mrow><mi>vert</mi></mrow></mrow></msub><mo>¯</mo></mover></math> (-0.08 ± 0.02). <math><mover><msub><mrow><mrow><mover><mi>P</mi><mo>^</mo></mover></mrow></mrow><mrow><mrow><mi>vert</mi></mrow></mrow></msub><mo>¯</mo></mover></math> is primarily induced by rotations of the thorax (0.04 ± 0.01), lumbar region (0.06 ± 0.02), and pelvis (0.04 ± 0.01). Rotations of the lower-limb segments did not contribute to upward propulsion. Therefore, the front thigh induces downward movement, which is counterbalanced by the trunk segments. We bridge the gap in the current understanding from joint power to <math><mover><msub><mrow><mrow><mover><mi>P</mi><mo>^</mo></mover></mrow></mrow><mrow><mrow><mi>hori</mi></mrow><mi>z</mi></mrow></msub><mo>¯</mo></mover></math>. We present a case involving segments on which positive joint powers are exerted similarly but play different roles: forward or upward propulsion, thereby providing insights into directional control mechanisms in explosive initiation of motion. HIGHLIGHTSWe examined the contributions of segment rotations to the normalised average horizontal and vertical external powers (<math><mover><msub><mrow><mrow><mover><mi>P</mi><mo>^</","PeriodicalId":12061,"journal":{"name":"European Journal of Sport Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40673357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultrasound and surface electromyography analyses reveal an intensity dependent active stretch-shortening cycle of the vastus lateralis muscle during ergometer rowing.","authors":"Steffen Held,&nbsp;Brent Raiteri,&nbsp;Ludwig Rappelt,&nbsp;Daniel Hahn,&nbsp;Lars Donath","doi":"10.1080/17461391.2022.2119434","DOIUrl":"10.1080/17461391.2022.2119434","url":null,"abstract":"<p><p>A rowing cycle is characterised by a stretch-shortening cycle (SSC) at the quadriceps femoris muscle-tendon unit (MTU) level. However, due to the associated decoupling between MTU and muscle fascicle length changes, it remains unclear whether a rowing cycle causes active stretch at the muscle level. Fifteen young, sub-elite, male rowers (19.5 ± 1.6 yr; 1.94 ± 0.06 m; 91.9 ± 5.4 kg; rowing experience: 7.5 ± 2.8 yr) performed randomised 60-s rowing intervals using a traditional style at a low (LiR) and high intensity (HiR) and a micro-pause style at a low intensity (MpR). Muscle activity, knee joint angles, and muscle fascicle length changes from the left-sided vastus lateralis (VL) muscle were quantified using surface electromyography, inertial measurement units, and B-mode ultrasound imaging, respectively. All rowing conditions showed active fascicle stretch during late knee flexion (<i>p</i>≤0.001, standardised mean difference (SMD) ≥0.72) and subsequent active fascicle shortening throughout knee extension. Active fascicle stretch duration, amplitude and velocity (rANOVA: <i>p</i>≤0.001, η_p²= 0.49) were not significantly different (<i>p</i>≥0.174; SMD≤0.26) between LiR and MpR, but were significantly increased during HiR (<i>p</i>≤0.001; SMD≥0.70). The percentage of rowing cycles that involved active fascicle stretch (rANOVA: <i>p</i>≤0.001, η_p²= 0.95; post-hoc: <i>p</i>≤0.001, SMD≥0.87) was also significantly higher for HiR (98.3 ±12.9%) compared with both LiR (65.0 ± 48.1%) and MpR (68.3 ± 46.9%). In conclusion, rowing involves SSC at the VL muscle fascicle level, but the amount of active stretch differs between rowing intensities, with the longest, largest, and fastest active stretch occurring during HiR. SSC-based mechanisms may therefore contribute more to rowing performance during HiR than LiR or MpR.<b>Highlights</b>Surface electromyography and ultrasound imaging revealed stretch-shortening cycles (SSCs) of the vastus lateralis muscle fascicles during rowingIncreased active fascicle stretch duration, amplitude and velocity from low- to high-intensity rowing indicate that SSC-based mechanisms likely contribute more to performance during high-intensity rowingThe SSC within the vastus lateralis muscle was independent of the rowing style at the same low rowing intensity.</p>","PeriodicalId":12061,"journal":{"name":"European Journal of Sport Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40332865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of acute manipulation of carbohydrate availability on high intensity running performance, running economy, critical speed, and substrate metabolism in trained Male runners.","authors":"Andrius Ramonas,&nbsp;Paul B Laursen,&nbsp;Micalla Williden,&nbsp;Andrew E Kilding","doi":"10.1080/17461391.2022.2130097","DOIUrl":"10.1080/17461391.2022.2130097","url":null,"abstract":"<p><p>Completing selected training sessions with reduced glycogen availability is associated with greater signalling and improved muscle oxidative capacity, although it may impact the overall quality of the session. We examined the effects of low carbohydrate availability on high intensity exercise performance, running economy, critical speed, and substrate metabolism. On two occasions, nine male runners (V̇O_2peak 60.3 ± 3.3 mL.kg^-1.min^-1) completed a glycogen depletion protocol involving 90-min at 75%vV̇O_2peak followed by 10 × 1-min at 110% vV̇O_2peak. This was followed either by high (HIGH) or low (LOW) carbohydrate intake (>6 g.kg^-1.day^-1 and <50 g.day^-1, respectively) until completion of a performance protocol on day 2 consisting of a series of time-trials (TT) (50m to 3000m) and physiological assessments. There were no differences between LOW and HIGH for any TT distance (mean TT performance times for LOW and HIGH were: 3000m TT 651.7 ± 52.8s and 646.4 ± 52.5s, 1500 m TT 304.0 ± 20.2s and 304.2 ± 22.1s, 400 m TT 67.64 ± 4.2s and 67.3 ± 3.8s, 50 m TT 7.27 ± 0.44s and 7.25 ± 0.45s, respectively, <i>P </i>> 0.05), though some athletes performed better in LOW (n = 5). While fat oxidation in LOW was significantly greater than HIGH (Δ0.32 ± 0.14 g.min^-1; <i>P </i>< 0.001 at 14 km.h^-1 and Δ0.34 ± 0.12 g.min^-1 at 16 km.h^-1; <i>P </i>< 0.01), running economy did not differ between trials (<i>P </i>> 0.05). Acute manipulation of carbohydrate availability showed immediate effects on substrate metabolism evidenced by greater fat oxidation without changes in RE. Acute low carbohydrate availability did not affect high intensity running performance across a range of distances.<b>Highlights</b> Acute manipulation of muscle glycogen availability using an exercise and dietary manipulation protocol did not affect subsequent high intensity running performance across a range of running distances.Reduced muscle glycogen resulted in a marked increase in fat oxidation in low glycogen condition but no changes in running economy or critical speed.Individual factors should be considered when prescribing high intensity sessions with restricted carbohydrate availability.</p>","PeriodicalId":12061,"journal":{"name":"European Journal of Sport Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40378663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Longitudinal haematological responses to training load and heat acclimation preceding a male team pursuit cycling world record.","authors":"Samuel T Tebeck,&nbsp;Jonathan D Buckley,&nbsp;Jamie Stanley","doi":"10.1080/17461391.2022.2150896","DOIUrl":"10.1080/17461391.2022.2150896","url":null,"abstract":"ABSTRACT This study evaluated relationships between changes in training load, haematological responses, and endurance exercise performance during temperate and heat acclimation (HA) training preceding a male team cycling pursuit world record (WR). Haemoglobin mass (Hbmass) and concentration ([Hb]), plasma volume (PV) and blood volume (BV) were assessed in nine male track endurance cyclists (∼3 occasions per month) training in temperate conditions (247–142 days prior to the WR) to establish responses to differing acute (ATL) and chronic (CTL) training loads. Testing was performed again pre- and post-HA (22–28 days prior to the WR). Endurance performance (V̇O₂max, 4MMP, lactate threshold 1 and 2) was assessed on three occasions (238–231, 189–182 and 133–126 days prior to the WR). In temperate conditions, CTL was associated with Hbmass (B = 0.62, P = 0.02), PV (B = 4.49, P = 0.01) and BV (B = 6.51, P = 0.04) but not [Hb] (B = −0.01, P = 0.17). ATL was associated with PV (B = 2.28, P < 0.01), BV (B = 2.63, P = 0.04) and [Hb] (B = −0.01, P = 0.04) but not Hbmass (B = 0.10, P = 0.41). During HA, PV increased 8.2% (P < 0.01), while Hbmass, CTL and ATL were unchanged. Hbmass and [Hb] were associated with all performance outcomes (P < 0.05), except V̇O2max. PV and BV were not associated with performance outcomes. During temperate training, changes in Hbmass were most strongly associated with changes in CTL. Both CTL and ATL were associated with changes in PV, but HA was associated with increased PV and maintenance of Hbmass without increasing ATL or CTL. In practical terms, maintaining high CTL and high Hbmass might be beneficial for improving endurance performance. HIGHLIGHTS Changes in haemoglobin mass were associated with endurance exercise performance and changes in chronic training load in temperate conditions. Heat acclimation increased plasma volume and maintained haemoglobin mass independently of chronic training load. Chronic training loads and haemoglobin mass should be increased to improve endurance exercise performance. Heat acclimation may optimise haematological adaptations when training load is reduced","PeriodicalId":12061,"journal":{"name":"European Journal of Sport Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10801761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interdisciplinary practice in performance sport: A scoping review of evidence of collaboration.","authors":"Andrew Burns,&nbsp;Dave Collins","doi":"10.1080/17461391.2023.2201812","DOIUrl":"10.1080/17461391.2023.2201812","url":null,"abstract":"<p><p>Performance support teams are increasingly comprised of sub-disciplines, bringing varied expertise to support an athlete or team in achieving the desired result. With more voices in the room, however, there is a need to investigate how these individuals can effectively work together collaboratively. Accordingly, the present study reviewed empirical articles that have examined interdisciplinary practice in performance sport. In total, 22 articles met the full inclusion criteria. We discuss the four key themes that emerged from the literature linked to these contexts: namely, <i>Theoretical frameworks, Facilitative leadership and culture, Organisational and logistical structure and processes, and Personal and interpersonal qualities</i>. To deepen the understanding in this intricate field, conducting future research such as longitudinal studies that follow team working practices over time and delve into the lived experiences of teams, as well as the perspectives of various stakeholders, would be beneficial.</p>","PeriodicalId":12061,"journal":{"name":"European Journal of Sport Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9457652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sport specialization in Swedish football players: Investigating a model of antecedents and outcomes.","authors":"Tor Söderström,&nbsp;Alex C Garn","doi":"10.1080/17461391.2022.2153084","DOIUrl":"10.1080/17461391.2022.2153084","url":null,"abstract":"<p><p>Drawing on data from the present and former football players (<i>N </i>= 1026) selected to a national football talent programme at the age of 15, this study explores a model of sport specialisation. We examined three specific aspects of sport specialisation including early football specialisation, participation in youth elite football training environments (i.e. academies) and enrolment in upper secondary football specialisation schools. Antecedents of these sport specialisation factors included gender (i.e. sociocultural), grit (i.e. personality) and perceptions of family finances (i.e. social). Outcomes focused on adult football participation at the age of 21 including elite skill acquisition (i.e. playing elite football) and personal development (i.e. participation in non-elite football). Findings revealed that females were less likely to gain access to elite football training or school specialisation environments. There was also a positive association between grit and participation in elite training environments. In terms of outcomes, players, who got trained in elite training environments during adolescence, were twice as likely to play elite football at the age of 21, while those who attended football specialisation schools were more likely to participate in non-elite football at the age of 21. Early specialisation was not associated with either adult participation outcome. This is one of the few studies to date addressing diverse antecedents and outcomes of sport specialisation factors. Understanding how sport specialisation practices relate to future skill acquisition and personal development can provide guidance for maximising the benefits of youth sport programming.<b>Highlights</b>Girls had less opportunity to participate in elite training environments and school football classes.Early specialisation was unrelated to elite football participation at the age of 21.Participation in youth elite training increased the likelihood of elite status as an adult.Need for closer examination of sport specialisation disparities for female players.</p>","PeriodicalId":12061,"journal":{"name":"European Journal of Sport Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10444297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring interindividual differences in fasting and postprandial insulin sensitivity adaptations in response to sprint interval exercise training.","authors":"Richard S Metcalfe,&nbsp;Brendon J Gurd,&nbsp;Niels B J Vollaard","doi":"10.1080/17461391.2022.2124385","DOIUrl":"10.1080/17461391.2022.2124385","url":null,"abstract":"<p><p>Previous studies have concluded that wide variance in changes in insulin sensitivity markers following exercise training demonstrates heterogeneity in individual trainability. However, these studies frequently don't account for technical, biological, and random within-subject measurement error. We used the standard deviation of individual responses (SD_IR) to determine whether interindividual variability in trainability exists for fasting and postprandial insulin sensitivity outcomes following low-volume sprint interval training (SIT). We pooled data from 63 untrained participants who completed 6 weeks of SIT (<i>n </i>= 49; VO₂max: 35 (7) mL⋅kg^-1⋅min^-1) or acted as no-intervention controls (<i>n </i>= 14; VO₂max: 34 (6) mL⋅kg^-1⋅min^-1). Fasting and oral glucose tolerance test (OGTT)-derived measures of insulin sensitivity were measured pre- and post-intervention. SD_IR values were positive and exceeded a small effect size threshold for changes in fasting glucose (SD_IR= 0.27 [95%CI 0.07,0.38] mmol⋅L^-1), 2-h OGTT glucose (SD_IR= 0.89 [0.22,1.23] mmol⋅L^-1), glucose area-under-the-curve (SD_IR= 66.4 [-81.5,124.3] mmol⋅L^-1⋅120min^-1) and The Cederholm Index (SD_IR= 7.2 [-16.0,19.0] mg⋅l²⋅mmol^-1⋅mU^-1⋅min^-1), suggesting meaningful individual responses to SIT, whilst SD_IR values were negative for fasting insulin, fasting insulin resistance and insulin AUC. For all variables, the 95% CIs were wide and/or crossed zero, highlighting uncertainty about the existence of true interindividual differences in exercise trainability. Only 2-22% of participants could be classified as responders or non-responders with more than 95% certainty. Our findings demonstrate it cannot be assumed that variation in changes in insulin sensitivity following SIT is attributable to inherent differences in trainability, and reiterate the importance of accounting for technical, biological, and random error when examining heterogeneity in health-related training adaptations.<b>Highlights</b> This study tested whether true interindividual variability exists for changes in insulin sensitivity and glyceamic control following 6-weeks of low volume sprint interval training (SIT).The high level of technical, biological, and random error associated with repeated measurements of insulin sensitivity and glycaemic control, means we can neither confidently conclude that there is evidence of true interindividual differences in the trainability of these outcomes following SIT, nor confidently identify responders or non-responders for such parameters.Researchers contrasting responders vs. non-responders for a given parameter, either to understand mechanisms of adaptation and/or develop physiological/genetic/epigenetic predictors of response, need to be aware that iden","PeriodicalId":12061,"journal":{"name":"European Journal of Sport Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33468169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ischaemic preconditioning improves upper-body endurance performance without altering V̇O₂ kinetics.","authors":"D Bellini,&nbsp;C Chapman,&nbsp;D Peden,&nbsp;S P Hoekstra,&nbsp;R A Ferguson,&nbsp;C A Leicht","doi":"10.1080/17461391.2022.2103741","DOIUrl":"https://doi.org/10.1080/17461391.2022.2103741","url":null,"abstract":"<p><strong>Purpose: </strong>Whilst pre-exercise ischaemic preconditioning (IPC) can improve lower-body exercise performance, its impact on upper-limb performance has received little attention. This study examines the influence of IPC on upper-body exercise performance and oxygen uptake (V̇O₂) kinetics.</p><p><strong>Methods: </strong>Eleven recreationally-active males (24 ± 2 years) completed an arm-crank graded exercise test to exhaustion to determine the power outputs at the ventilatory thresholds (VT1 and VT2) and V̇O_2peak (40.0 ± 7.4 ml·kg^-1·min^-1). Four main trials were conducted, two following IPC (4 × 5-min, 220 mmHg contralateral upper-limb occlusion), the other two following SHAM (4 × 5-min, 20 mmHg). The first two trials consisted of a 15-minute constant work rate and the last two time-to-exhaustion (TTE) arm-crank tests at the power equivalents of 95% VT1 (LOW) and VT2 (HIGH), respectively. Pulmonary V̇O₂ kinetics, heart rate, blood-lactate concentration, and rating of perceived exertion were recorded throughout exercise.</p><p><strong>Results: </strong>TTE during HIGH was longer following IPC than SHAM (459 ± 115 vs 395 ± 102 s, <i>p </i>= .004). Mean response time and change in V̇O₂ between 2-min and end exercise (ΔV̇O₂) were not different between IPC and SHAM for arm-cranking at both LOW (80.3 ± 19.0 vs 90.3 ± 23.5 s [<i>p </i>= .06], 457 ± 184 vs 443 ± 245 ml [<i>p </i>= .83]) and HIGH (96.6 ± 31.2 vs 92.1 ± 24.4 s [<i>p </i>= .65], 617 ± 321 vs 649 ± 230 ml [<i>p </i>= .74]). Heart rate, blood-lactate concentration, and rating of perceived exertion did not differ between conditions (all <i>p</i> ≥ .05).</p><p><strong>Conclusion: </strong>TTE was longer following IPC during upper-body exercise despite unchanged V̇O₂ kinetics.<b>Highlights</b>Whilst pre-exercise ischaemic preconditioning can improve lower-body exercise performance and alter V̇O₂ kinetics, its impact on upper-limb performance has received little attention.An acute bout of ischaemic preconditioning prior to arm-crank ergometry exercise significantly improved time to exhaustion compared to a sham control condition.V̇O₂ kinetics in response to ischaemic preconditioning remained unchanged, suggesting alternative mechanisms may explain performance improvements.</p>","PeriodicalId":12061,"journal":{"name":"European Journal of Sport Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9944948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Blood flow restricted walking alters gait kinematics.","authors":"Thomas P Walden,&nbsp;Timothy Fairchild,&nbsp;Olivier Girard,&nbsp;Jeremiah J Peiffer,&nbsp;Andrew M Jonson,&nbsp;Alasdair R Dempsey","doi":"10.1080/17461391.2023.2194274","DOIUrl":"https://doi.org/10.1080/17461391.2023.2194274","url":null,"abstract":"<p><p>This study investigated the impact of blood flow restriction (BFR) during treadmill walking on gait kinematics. Twenty-one participants completed one familiarisation and four experimental sessions, including two walking speeds (moderate [5.0 ± 0.3km·h^-1] and fast [6.4 ± 0.4km·h^-1]) and two occlusion conditions (BFR [60% of arterial occlusion pressure] and unrestricted). For each exercise intensity, the BFR session was performed first. Participants were instructed to walk as long as possible, with sessions capped at 20 min. Unrestricted sessions were time-matched, and the order of exercise intensity was randomised. Kinematics were collected over 10s every minute using retro-reflective markers affixed to specific body landmarks. Ratings of perceived exertion and discomfort were collected every two minutes. Blood samples were collected from the fingertip pre-exercise and the finger and toe post-exercise, and were analysed for lactate, electrolytes, and markers of cell-membrane damage. During the BFR sessions the cuffs remained inflated while the blood samples were collected. Fast-walk BFR sessions exhibited higher anterior trunk flexion (<i>p </i>= 0.001) and knee flexion during stance (<i>p </i>= 0.001) compared to all other sessions. Step width was increased during BFR sessions (<i>p </i>= 0.001), but no difference in step length (<i>p </i>= 0.300) or cadence (<i>p </i>= 0.922) were observed. The time required to elicit change in anterior trunk flexion and plantar-flexion angle at toe-off was shorter during BFR sessions (<i>p </i>= 0.024). The BFR sessions elicited the highest ratings of perceived exertion and discomfort, as well as blood lactate concentration (<i>p</i> ≤ 0.001). Application of BFR during moderate and fast treadmill walking modifies gait kinematics and exacerbates exercise-related sensations as well as blood lactate concentration.</p>","PeriodicalId":12061,"journal":{"name":"European Journal of Sport Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9996949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interindividual variability in metabolic adaptation of non-exercise activity thermogenesis after a 1-year weight loss intervention in former elite athletes.","authors":"Catarina L Nunes,&nbsp;Gil B Rosa,&nbsp;Filipe Jesus,&nbsp;Steven B Heymsfield,&nbsp;Cláudia S Minderico,&nbsp;Paulo Martins,&nbsp;Luis B Sardinha,&nbsp;Analiza M Silva","doi":"10.1080/17461391.2022.2147020","DOIUrl":"https://doi.org/10.1080/17461391.2022.2147020","url":null,"abstract":"<p><p>Lack of efficacy of weight loss(WL) interventions is attributed in-part to low adherence to dietary/physical activity(PA) recommendations. However, some compensation may occur in PA as a response to energy restriction such as a decrease in non-exercise PA(NEPA) or non-exercise activity thermogenesis(NEAT). The current study aim was (1) to investigate whether adaptive thermogenesis(AT) in NEAT occurs after WL, and (2) to understand the associations of these compensations with WL. Ninety-four former athletes [mean±SD, age: 43.0±9.4y, BMI: 31.1±4.3 kg/m², 34.0% female] were recruited and randomly assigned to intervention or control groups (IG, CG). The IG underwent a one-year lifestyle WL-intervention; no treatments were administered to the CG. PA was measured using accelerometery and NEAT was predicted with a model including sample baseline characteristics. AT was calculated as _measuredNEAT^4mo/12mo_(kcal/d)-_predictedNEAT^4mo/12mo_(kcal/d)-_measuredNEAT^baseline_(kcal/d)-_predictedNEAT^baseline_(kcal/d). Dual-energy x-ray absorptiometry was used to assess fat-free mass and fat mass. No differences were found in the IG for NEAT or NEPA after WL. Considering mean values, AT was not found for either group. The SD of individual response (SD_IR) for AT was -2(4-months) and 24(12-months) (smallest worthwhile change = 87kcal/d), suggesting that the interindividual variability regarding AT in NEAT is not relevant and the variability in this outcome might reflect a large within-subject variability and/or a large degree of random measurement error. No associations were found between AT in NEAT and changes in body composition. Further studies are needed to clarify the mechanisms behind the large variability in AT observed in NEAT and related changes in NEPA to better implement lifestyle-induced WL interventions.<b>Highlights</b>No significant differences were found for non-exercise activity thermogenesis (NEAT) or non-exercise physical activity (NEPA) after the weight loss (WL) intervention;Although a large variability was found for NEAT and NEPA, the interindividual variability regarding these outcomes is not relevant. The variability in these outcomes might reflect a large within-subject variability and/or a large degree of random measurement error;Although no energy conservation was observed in NEAT after moderate WL (mean values), further studies are needed to clarify the mechanisms behind the large variability in adaptive thermogenesis observed in NEAT and related changes in NEPA to better implement lifestyle-induced WL interventions.<b>Trial registration:</b> ClinicalTrials.gov identifier: NCT03031951.</p>","PeriodicalId":12061,"journal":{"name":"European Journal of Sport Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9933060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}