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1.
EMBO J ; 42(24): e113590, 2023 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-38073509

RESUMEN

Cells secrete extracellular vesicles (EVs) and non-vesicular extracellular (nano)particles (NVEPs or ENPs) that may play a role in intercellular communication. Tumor-derived EVs have been proposed to induce immune priming of antigen presenting cells or to be immuno-suppressive agents. We suspect that such disparate functions are due to variable compositions in EV subtypes and ENPs. We aimed to characterize the array of secreted EVs and ENPs of murine tumor cell lines. Unexpectedly, we identified virus-like particles (VLPs) from endogenous murine leukemia virus in preparations of EVs produced by many tumor cells. We established a protocol to separate small EVs from VLPs and ENPs. We compared their protein composition and analyzed their functional interaction with target dendritic cells. ENPs were poorly captured and did not affect dendritic cells. Small EVs specifically induced dendritic cell death. A mixed large/dense EV/VLP preparation was most efficient to induce dendritic cell maturation and antigen presentation. Our results call for systematic re-evaluation of the respective proportions and functions of non-viral EVs and VLPs produced by murine tumors and their contribution to tumor progression.


Asunto(s)
Retrovirus Endógenos , Vesículas Extracelulares , Neoplasias , Animales , Ratones , Vesículas Extracelulares/metabolismo , Línea Celular Tumoral , Diferenciación Celular , Células Dendríticas , Neoplasias/metabolismo
2.
EMBO J ; 40(6): e104683, 2021 03 15.
Artículo en Inglés | MEDLINE | ID: mdl-33620739

RESUMEN

Regulatory switches are wide spread in many biological systems. Uniquely among them, the switch of the bacterial flagellar motor is not an on/off switch but rather controls the motor's direction of rotation in response to binding of the signaling protein CheY. Despite its extensive study, the molecular mechanism underlying this switch has remained largely unclear. Here, we resolved the functions of each of the three CheY-binding sites at the switch in E. coli, as well as their different dependencies on phosphorylation and acetylation of CheY. Based on this, we propose that CheY motor switching activity is potentiated upon binding to the first site. Binding of potentiated CheY to the second site produces unstable switching and at the same time enables CheY binding to the third site, an event that stabilizes the switched state. Thereby, this mechanism exemplifies a unique combination of tight motor regulation with inherent switching flexibility.


Asunto(s)
Escherichia coli/fisiología , Flagelos/metabolismo , Locomoción/fisiología , Proteínas Quimiotácticas Aceptoras de Metilo/metabolismo , Proteínas Motoras Moleculares/metabolismo , Proteínas Bacterianas , Proteínas de Escherichia coli , Unión Proteica/fisiología
3.
Clin Anat ; 37(2): 210-217, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38058252

RESUMEN

OBJECTIVE: We challenge the paradigm that a simplistic approach evaluating anatomic regions (e.g., medial femur or tibia) is ideal for assessing articular cartilage loss on magnetic resonance (MR) imaging. We used a data-driven approach to explore whether specific topographical locations of knee cartilage loss may identify novel patterns of cartilage loss over time that current assessment strategies miss. DESIGN: We assessed 60 location-specific measures of articular cartilage on a sample of 99 knees with baseline and 24-month MR images from the Osteoarthritis Initiative, selected as a group with a high likelihood to change. We performed factor analyses of the change in these measures in two ways: (1) summing the measures to create one measure for each of the six anatomically regional-based summary (anatomic regions; e.g., medial tibia) and (2) treating each location separately for a total of 60 measures (location-specific measures). RESULTS: The first analysis produced three factors accounting for 66% of the variation in the articular cartilage changes that occur over 24 months of follow-up: (1) medial tibiofemoral, (2) medial and lateral patellar, and (3) lateral tibiofemoral. The second produced 20 factors accounting for 75% of the variance in cartilage changes. Twelve factors only involved one anatomic region. Five factors included locations from adjoining regions (defined by the first analysis; e.g., medial tibiofemoral). Three factors included articular cartilage loss from disparate locations. CONCLUSIONS: Novel patterns of cartilage loss occur within each anatomic region and across these regions, including in disparate regions. The traditional anatomic regional approach is simpler to implement and interpret but may obscure meaningful patterns of change.


Asunto(s)
Cartílago Articular , Osteoartritis de la Rodilla , Humanos , Osteoartritis de la Rodilla/diagnóstico por imagen , Osteoartritis de la Rodilla/patología , Fémur , Articulación de la Rodilla/diagnóstico por imagen , Articulación de la Rodilla/patología , Imagen por Resonancia Magnética/métodos , Tibia/patología , Cartílago Articular/diagnóstico por imagen , Cartílago Articular/patología , Espectroscopía de Resonancia Magnética
4.
J Strength Cond Res ; 38(6): 1063-1071, 2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38349345

RESUMEN

ABSTRACT: Finlay, MJ, Greig, M, Bridge, CA, and Page, RM. Post-activation performance enhancement of punch force and neuromuscular performance in amateur boxing: Toward a more individualized and "real-world" approach. J Strength Cond Res 38(6): 1063-1071, 2024-Previous research on post-activation performance enhancement has been applied in several sporting settings, although this is lacking in a boxing setting. This study explored the effectiveness of 2 upper-body conditioning activities in improving punch-specific performance during an amateur boxing-simulated bout. On 3 separate occasions, 10 male senior elite amateur boxers performed the following conditioning activities before a boxing-specific simulation protocol: isometric (ISO) punch, elastic resistance (ER) punch, and a control trial. Boxers performed maximal punches against a vertically mounted force plate, and countermovement jumps (CMJ) at baseline, before round 1, after each round, and 4 minutes after the simulation. Both conditioning activities, but not the control trial, produced small worthwhile increases (effect size ≥ 0.20; equal to or greater than the smallest worthwhile change) in punch force, although worthwhile increases in rate of force development were limited to the cross during the ISO trial. No group-based improvements in CMJ performance were observed. Individual analysis revealed that 6 boxers improved punch-specific performance to the greatest extent in the ISO trial; in contrast, only 1 boxer did so in the ER trial. Three boxers exhibited similar performance increases across trials. In conclusion, both conditioning activities may be applied to an amateur boxer's warm-up to acutely enhance punch-specific performance. The ISO conditioning activity seems most effective; however, the interindividual variability suggests a need for protocols to be individualized to each athlete. The conditioning activities in the present study may be applied to sparring, competitive bouts, or to other combat sports.


Asunto(s)
Rendimiento Atlético , Boxeo , Fuerza Muscular , Humanos , Masculino , Rendimiento Atlético/fisiología , Boxeo/fisiología , Adulto Joven , Fuerza Muscular/fisiología , Entrenamiento de Fuerza/métodos , Entrenamiento de Fuerza/instrumentación , Contracción Isométrica/fisiología , Adulto , Acondicionamiento Físico Humano/métodos , Acondicionamiento Físico Humano/fisiología , Músculo Esquelético/fisiología
5.
Res Sports Med ; 31(4): 491-505, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-34747292

RESUMEN

This study sought to examine differences in measures of intense periods of physical performance during competitive match-play, between one-match (1 match weeks) and two-match microcycles (2 match week). 1, 3 and 5 min "peak" and mean averages for total distance (TD), high-speed running (HSR) and metabolic power (MP) were analysed for each 15 min period of match-play. Linear mixed models were employed to examine the differences in dependent variables for each method of measurement between the 1 and 2 game microcycles. No differences were reported for "peak" values for all epoch lengths, however, results revealed significantly reduced "average" values, during periods of fixture congestion, for 1, 3 and 5 min epochs for average TD, and 3 min epochs for average HSR towards the end of the match (75-90 min split). There was, however, a trend for the opposite response to occur in the 60-75-min period. The current data suggests that players potentially display altered pacing strategies during periods of fixture congestion, with these observed responses being dependent on sampling method and epoch length.


Asunto(s)
Rendimiento Atlético , Carrera , Fútbol , Humanos , Rendimiento Atlético/fisiología , Fútbol/fisiología , Modelos Lineales , Carrera/fisiología
6.
Mol Biol Rep ; 49(8): 7743-7752, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35715608

RESUMEN

BACKGROUND: Aneuploidy is associated with add or lack of individual chromosomes. The knowledge regarding aneuploidy is still rare in wild and tropical populations. Lippia alba is a tropical polyploid complex naturally formed, with 2x, 3x, 4x, 6x, and aneuploid individuals. The species presents pharmacological and medicinal importance, due to its essential oil compounds, which are related to the ploidal level. Considering the singularity of aneuploids emergence and stability, we proposed to investigate putative cytotypes involved in the aneuploids formation. METHODS AND RESULTS: Molecular, cytogenetic, reproductive, and chemical approaches were adopted. The results showed that the aneuploids possibly have independent origin considering the genetic, chemical and karyotypical profiles. The chemical composition of aneuploids is related to genetic similarity. The aneuploid origin may involve 2x and 3x cytotypes being possible to rise four scenarios of crosses to explain that. CONCLUSIONS: The results, in general, contribute to the comprehension of the origin of aneuploids and highlight the genetic profile of these accessions as a key element on the understanding of the chemical profile of L. alba accessions.


Asunto(s)
Lippia , Aneuploidia , Humanos , Lippia/genética , Poliploidía
7.
Occup Environ Med ; 79(8): 543-549, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35618387

RESUMEN

OBJECTIVE: Occupations involving greater physical activity may increase risk for knee osteoarthritis (OA). Existing studies have not evaluated work-related physical activity before OA onset. Hence, we aimed to evaluate the association between work-related physical activity and knee OA incidence. METHODS: We performed a person-based longitudinal study using Osteoarthritis Initiative (OAI) data among people who volunteered or worked for pay without baseline radiographic knee OA or knee pain. Bilateral knee radiographs were obtained at baseline and annual follow-ups. We defined radiographic OA as Kellgren-Lawrence grade ≥2. Questions from the Physical Activity Scale for the Elderly at baseline and annual OAI visits provided information about work-related physical activity level and hours. We performed logistic regression with work-related physical activity level ( mainly sitting , standing and some walking , walking while handling some materials ) and hours as predictors. The outcome was incident person-based radiographic OA within the ensuing 12 months, over 48 months. RESULTS: Among 951 participants (2819 observations), higher work-related physical activity levels had greater adjusted ORs for incident radiographic OA (people with jobs with standing and some walking : 1.11 (0.60-2.08), and walking while handling some materials : 1.90 (1.03-3.52), when compared with those with mainly sitting work-related activity ). There was no association between number of hours worked and incident radiographic OA. CONCLUSIONS: People performing work that require walking while handling some materials have greater odds of incident knee OA than those with jobs mostly involving sitting. Strategies are needed to mitigate risk factors predisposing them to radiographic OA.


Asunto(s)
Osteoartritis de la Rodilla , Anciano , Ejercicio Físico , Humanos , Articulación de la Rodilla , Estudios Longitudinales , Osteoartritis de la Rodilla/diagnóstico por imagen , Osteoartritis de la Rodilla/epidemiología , Osteoartritis de la Rodilla/etiología , Radiografía , Factores de Riesgo
8.
Photodermatol Photoimmunol Photomed ; 38(5): 409-417, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34967477

RESUMEN

BACKGROUND: Vitiligo may be treated with hospital-based phototherapy, but this requires long-term frequent appointments. Self-treatment using home-based phototherapy is a convenient alternative, which may improve adherence and results, but evidence is limited, and so it is not routinely recommended. This systematic review aims to assess the effectiveness and safety of home-based phototherapy for vitiligo. METHODOLOGY: Searches were conducted on Medline, Scopus and The Cochrane Library for randomised controlled trials comparing home-based phototherapy with institution-based phototherapy or placebo/no phototherapy for vitiligo. The primary outcome was treatment effectiveness. CASP criteria were used for quality assessment. Data were synthesised in a meta-analysis where appropriate. RESULTS: Three studies (195 participants) were included: two compared home-based with institution-based phototherapy, and one compared home-based phototherapy with placebo. Studies were of mixed quality. Therapy regimes varied across studies. Findings on effectiveness were contradictory across studies with variable rates of repigmentation. There was no significant difference in repigmentation rates between the groups, although adherence to treatment schedules was significantly better in home-based groups. Adverse effects were significantly higher in home-based groups. No long-term data were reported on maintenance of treatment benefits. CONCLUSIONS: Although adherence to treatment was significantly better with home-based phototherapy, data were insufficient to form conclusions on effectiveness. Home-based phototherapy had a significantly higher risk of adverse effects, making it difficult to recommend in clinical practice. However, as it offers logistical advantages for patients, its effectiveness alongside additional safety measures should be explored further in large-scale, good-quality RCTs, with standardised outcome measures, including patient-reported outcomes.


Asunto(s)
Fototerapia , Vitíligo/terapia , Humanos , Medición de Resultados Informados por el Paciente , Fototerapia/métodos , Ensayos Clínicos Controlados Aleatorios como Asunto , Autocuidado , Resultado del Tratamiento
9.
Rheumatol Int ; 42(6): 1063-1072, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35460352

RESUMEN

To assess the potential of studying offspring of people with and without knee osteoarthritis to understand the risk factors and heritability for knee osteoarthritis. We selected two groups of Osteoarthritis Initiative (OAI) participants from one clinical site: (1) participants with bilateral radiographic medial tibiofemoral osteoarthritis and (2) those without tibiofemoral osteoarthritis. We then invited biological offspring ≥ 18 years old to complete an online survey that inquired about osteoarthritis risk factors and symptoms. Among the survey respondents, we recruited ten offspring of members from each group for a clinic visit with bilateral knee posterior-anterior radiographs and magnetic resonance imaging of the right knee. We established contact with 269/413 (65%) eligible OAI participants. Most (227/269, 84%) had ≥ 1 eligible biological offspring, and 213 (94%) were willing to share information about the new family study with their offspring. Our survey was completed by 188 offspring from 110 OAI participants: mean age of 43.0 (10.4) years, mean body mass index of 23.7 (5.9) kg/m2, 65% female. Offspring obesity (OR = 2.7, 95% CI 1.0-7.3), hypertension (OR = 3.7, 95% CI 1.2-11.3), and Heberden's nodes (OR = 3.6, 95% CI 1.0-13.2) were associated with parental osteoarthritis status; however, adjusted models were not statistically significant. Radiographic tibiofemoral osteoarthritis (16/18 knees vs. 2/20 knees) and meniscal abnormalities (7/9 vs. 2/10 index knees) were more common among offspring with parental osteoarthritis status than not. We established the potential of a novel offspring study design within the OAI, and our results are consistent with bilateral radiographic medial tibiofemoral osteoarthritis being a heritable phenotype of osteoarthritis.


Asunto(s)
Osteoartritis de la Rodilla , Progresión de la Enfermedad , Femenino , Humanos , Articulación de la Rodilla/diagnóstico por imagen , Articulación de la Rodilla/patología , Imagen por Resonancia Magnética/métodos , Masculino , Osteoartritis de la Rodilla/diagnóstico por imagen , Osteoartritis de la Rodilla/genética , Fenotipo , Radiografía
10.
J Sports Sci ; 40(11): 1235-1242, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35389325

RESUMEN

The purpose of this study was to assess whether dynamic torque ratios (DCR) from isokinetic strength assessments of eccentric knee flexors (eccKF) and concentric knee extensors (conKE) display differences when stratified into specific angle-specific DCR (DCRAST) groups. Fifty-two professional female soccer players (age 21.30 ± 4.44 years; height 166.56 ± 5.17 cm; mass 61.55 ± 5.73 kg) from the English Women's Super League completed strength assessments of both lower limbs on an isokinetic dynamometer at 60°âˆ™s-1. Angle-specific torque (AST) were used to calculate DCRAST to create sub-groups using clustering algorithms. The results identified for the dominant side that the Medium DCRAST group elicited significantly higher conKE AST when compared to Low and High DCRAST groups at increased knee extension (P ≤ 0.05). For the non-dominant side, the High DCRAST group had significantly higher and lower eccKF and conKE AST compared to the Low DCRAST group at increased knee extension (P ≤ 0.05). This study highlights that the inclusion of AST data may subsequently help practitioners to prescribe exercise that promotes strength increases at targeted joint angles. In turn, these approaches can be used to help reduce injury risk, identify rehabilitation responses and help inform return to play.


Asunto(s)
Fútbol , Adolescente , Adulto , Femenino , Humanos , Rodilla/fisiología , Articulación de la Rodilla , Fuerza Muscular/fisiología , Músculo Esquelético/fisiología , Fútbol/fisiología , Torque , Adulto Joven
11.
J Intellect Disabil ; 26(1): 149-165, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33176550

RESUMEN

In Botswana, Special Needs Education has been implemented for 25 years with some success but there is still a need for evidence-based methods like Frequency Building, behavioural fluency, and Precision Teaching to be used to measure and improve school performance and learning. We explored the impact of these behavioural technologies on reading performances of four children with learning disorders (ADHD, speech impairment and acquired brain disorder) in a special school in Gaborone. At the assessment, two children were unable to read letter sounds and two could not read sight words. Reading performances were measured with frequency and displayed on a standard celeration chart. During the intervention, the length of the tasks was reduced and then augmented. Findings revealed that after 3 months of intervention children significantly increased their score stimulating self-confidence and enthusiasm during activities. This work demonstrates that behavioural technologies can be applied in Africa without using expensive or time-consuming resources.


Asunto(s)
Discapacidad Intelectual , Discapacidades para el Aprendizaje , Logro , Botswana , Niño , Humanos , Lectura
12.
Biol Sport ; 39(1): 171-179, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-35173375

RESUMEN

Research has demonstrated that the extra-time (ET) period of soccer negatively impacts recovery. However, it is not known to what extent recovery practices are being adapted by practitioners following ET and where gaps exist between research and practice. Therefore, this study explored soccer practitioner perceptions of recovery practices following ET matches. A total of 72 practitioners from across different levels of soccer and several countries completed a bespoke online survey. Inductive content analysis of the responses identified five higher-order themes: 'conditioning', 'player monitoring', 'recovery practices', 'training', and 'future research directions'. Mixed responses were received in relation to whether practitioners condition players in preparation for ET, though 72% allowed players to return to training based on fatigue markers following this additional 30-min period. Sixty-three (88%) practitioners believed that ET delays the time-course of recovery, with 82% highlighting that practices should be adapted following ET compared with a typical 90-min match. Forty-nine practitioners (68%) reduce training loads and intensities for up to 48 hr post ET matches, though training mostly recommences as 'normal' at 72 hr. Sixty-three (88%) practitioners believed that more research should be conducted on recovery following ET, with 'tracking players physiological and physical responses', 'nutritional interventions to accelerate recovery' and 'changes in acute injury-risk' being the three areas of research that practitioners ranked as most important. These data suggest practitioners and coaches adjust recovery practices following ET matches compared to 90 min. Further research on the efficacy of recovery strategies following ET matches is required to inform applied practice.

13.
Aust Crit Care ; 34(2): 155-159, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32773357

RESUMEN

BACKGROUND: Coronavirus Disease-19 (COVID-19) is associated with a high rate of thrombosis, the pathophysiology of which is not well defined. Viscoelastic testing may identify and characterise hypercoagulable states which are not apparent using conventional coagulation assays. OBJECTIVES: The objective of this study was to undertake viscoelastic evaluation of the coagulation state in critically ill adults with COVID-19-associated respiratory failure METHODS: This was a single-centre observational point prevalence cohort study of adults with COVID-19-associated respiratory failure requiring respiratory support in the intensive care unit. Coagulation status was evaluated using rotational thromboelastometry (ROTEM®) in conjunction with laboratory markers of coagulation. RESULTS: Six patients fulfilled inclusion criteria. Each patient had one ROTEM® performed. All patients had supranormal clot amplitude at 10 min (A10) and supranormal clot firmness (maximal clot firmness) measured in at least one ROTEM® pathway, and five were supranormal on all pathways. Minimal clot lysis was present on all analyses. Fibrinogen and D-dimer were elevated and routine markers of coagulation within normal ranges in all patients. CONCLUSION: Patients with COVID-19-associated respiratory failure admitted to the intensive care unit exhibit a hypercoagulable state which is not appreciable on conventional tests of coagulation. Supranormal clot firmness, minimal fibrinolysis, and hyperfibrinogenaemia are key findings. Further research is required into the pathophysiology of this hypercoagulable state, as well as the harms and benefits of different anticoagulation strategies.


Asunto(s)
Trastornos de la Coagulación Sanguínea/diagnóstico , Trastornos de la Coagulación Sanguínea/virología , COVID-19/sangre , Unidades de Cuidados Intensivos , Neumonía Viral/sangre , Tromboelastografía/métodos , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neumonía Viral/virología , Prevalencia , SARS-CoV-2 , Índice de Severidad de la Enfermedad , Australia del Sur
14.
J Anat ; 237(6): 1177-1184, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32706924

RESUMEN

Macroscopic anatomy has traditionally been taught using cadaveric material, lectures and a variable amount of additional resources such as online modules. Anatomical models have also been used to assist in teaching. Of these, traditional plastic models have been shown to be effective educational tools, yet have significant drawbacks such as a lack of anatomical detail and texturisation. Three-dimensional (3D) printed models stand to solve these problems and widen access to high-quality anatomical teaching. This paper outlines the use of 3D multi-planar imaging (CT and MRI) as a framework to develop an accurate model of the retroperitoneum. CT and MRI scans were used to construct a virtual 3D model of the retroperitoneum. This was printed locally as a full-size colour model for use in medical education. We give a complete account of the processes and software used. This study is amongst the first of a series in which we will document the newly formed Oxford Library of Anatomy. This series will provide the methodology for the production of models from CT and MRI scans, and the Oxford Library of Anatomy will provide a complete series of some of the most complex anatomical areas and ones which degrade quickly when a real cadaver is being used. In our own internal experience, the models are highly accurate, reproducible and durable, as compared to prosected specimens. We hope they will form an important adjunct in the teaching of the subject.


Asunto(s)
Abdomen/anatomía & histología , Imagenología Tridimensional/métodos , Región Lumbosacra/anatomía & histología , Modelos Anatómicos , Pelvis/anatomía & histología , Abdomen/diagnóstico por imagen , Educación de Pregrado en Medicina , Humanos , Región Lumbosacra/diagnóstico por imagen , Imagen por Resonancia Magnética , Pelvis/diagnóstico por imagen , Impresión Tridimensional , Tomografía Computarizada por Rayos X
15.
J Sports Sci ; 38(16): 1877-1885, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32508286

RESUMEN

With potential implications for recovery and conditioning practices, the aim of this study was to assess the cumulative and residual response of angle specific eccentric knee flexor (eccKF) strength indices following soccer-specific activity. Thirteen semi-professional soccer players were therefore required to complete a 90-minute soccer-specific treadmill running. with eccKF isokinetic strength assessments completed pre-trial, immediately post-trial, and 48 hours post-trial. The strength assessments comprised the completion of 5 repetitions at angular velocities of 60 and 300 deg·s-1. Isokinetic data was analysed for measures of peak torque (PT), angle of peak torque (APT), functional range (FR), and angle specific torque (AST). Significant post-trial impairments were observed for measures of slow velocity PT60 (6.6%) and AST300 (12.5%). Further significant differences were observed 48 hours post-trial for PT300 (10.7%) and PT60 (12.8%) PT, APT60 (~15°), and AST300 (>13.6%). These data have implications for post exercise recovery monitoring and the prescription of recovery modalities and conditioning practices in the 2 days following match-play. The AST and APT responses highlight the importance of analysis of the entire strength-angle curve and at a range of angular velocities.


Asunto(s)
Rodilla/fisiología , Fuerza Muscular/fisiología , Carrera/fisiología , Fútbol/fisiología , Adulto , Humanos , Masculino , Fatiga Muscular/fisiología , Dinamómetro de Fuerza Muscular , Músculo Esquelético/fisiología , Factores de Tiempo , Torque , Adulto Joven
16.
J Sports Sci ; 38(2): 140-149, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31680636

RESUMEN

The aim of this study was to assess the influence of a half-time (HT) re-warm up (RWU) strategy on measures of performance and the physical and perceptual response to soccer-specific activity. Ten male soccer players completed a control (CON) and RWU trial, in which participants completed 60 min (4 x 15-min periods with a 15-min HT interspersing the third and fourth periods) of a soccer-specific exercise protocol. The CON trial comprised a passive 15-min HT, whilst the RWU trial comprised a passive 12-min period, followed by a 3-min RWU. The RWU elicited an improvement in 20 m sprint times (d= 0.6; CON: 3.42 ± 0.20 s; RWU: 3.32 ± 0.12 s), and both squat (d= 0.6; CON: 26.96 ± 5.00 cm; RWU: 30.17 ± 5.13 cm) and countermovement jump height (d= 0.7; CON: 28.15 ± 4.72 cm; RWU: 31.53 ± 5.43 cm) following the RWU and during the initial stages of the second half. No significant changes were identified for 5 m or 10 m sprint performance, perceived muscle soreness, or PlayerLoadTM. Ratings of perceived exertion were however higher (~2 a.u) following the RWU. These data support the use of a HT RWU intervention to elicit acute changes in performance.


Asunto(s)
Rendimiento Atlético/fisiología , Rendimiento Atlético/psicología , Fútbol/fisiología , Ejercicio de Calentamiento/fisiología , Adulto , Estudios Cruzados , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Mialgia/psicología , Percepción/fisiología , Esfuerzo Físico/fisiología , Proyectos Piloto , Ejercicio Pliométrico/psicología , Adulto Joven
17.
J Sports Sci ; 38(5): 568-575, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32019482

RESUMEN

This study aimed to assess the effect of playing surface (Natural [NT] and Artificial [AT] Turf) on the fatigue response to a soccer-specific exercise protocol (SSEP). Eighteen male soccer players completed the SSEP on NT and AT with pre-, post-, and 48 h post-assessments of eccentric knee flexor (eccKF) and concentric knee extensor peak torque (PT), peak countermovement (CMJ) and squat jump (SJ) height, and Nordic hamstring break angle. No significant main effects for surface or any surface and time interactions were observed for any of the outcome measures, except for eccKF PT recorded at 3.14 rad·s-1, which was significantly lower 48 h post-trial in the AT condition (AT = 146.3 ± 20.4 Nm; NT = 158.8 ± 24.7 Nm). Main effects for time were observed between pre- and post-trial measures for eccKF PT at all angular velocities, Nordic break angle, CMJ and SJ height. Nordic break angle, and both CMJ and SJ height were significantly impaired 48 h post-trial when compared to pre-trial. The findings of the current study suggest surface dependent changes in eccKF PT which may have implications for recovery and subsequent performance after competition on AT.


Asunto(s)
Planificación Ambiental , Ejercicio Físico/fisiología , Articulación de la Rodilla/fisiología , Fatiga Muscular/fisiología , Músculo Esquelético/fisiología , Fútbol/fisiología , Adulto , Rendimiento Atlético/fisiología , Estudios Cruzados , Músculos Isquiosurales/fisiología , Humanos , Masculino , Fenómenos Fisiológicos Musculoesqueléticos , Rendimiento Físico Funcional , Rango del Movimiento Articular , Fútbol/lesiones , Torque , Adulto Joven
18.
Skin Res Technol ; 25(5): 743-749, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31127665

RESUMEN

BACKGROUND: Increased tissue stiffness (also termed modulus) has been shown to be a characteristic of potential tumor metastasis. Measured values of the stiffness of tumors and cancer cells are reported in the literature to increase compared to neighboring normal tissues. Yet the relationship between the mechanical properties of cells and the extracellular matrix has yet to be correlated with the histopathology of cancerous lesions. MATERIALS AND METHODS: We have developed a technique to do virtual biopsies of skin lesions by combining images made using optical coherence tomography with stiffness measurements made simultaneously using vibrational analysis. The technique is termed vibrational optical coherence tomography (VOCT). RESULTS: In this paper, we report that precancerous and cancerous lesions are characterized by changes in both the morphology and stiffness of the cellular components of the skin. The ratio of the peak heights that correspond to the epidermal (40-60Hz) and dermal (140-160 Hz) resonant frequencies appear to be different for benign and cancerous or precancerous lesions compared with normal skin and scar. CONCLUSIONS: Cell-to-cell and epidermal-to-dermal interactions may be very important in evaluating the potential of skin lesions to become malignant. These interactions can be evaluated using VOCT, a new technique for performing "virtual biopsies" of skin lesions.


Asunto(s)
Nevo Pigmentado/patología , Neoplasias Cutáneas/patología , Piel/patología , Biopsia/métodos , Cicatriz/diagnóstico por imagen , Cicatriz/patología , Dermis/diagnóstico por imagen , Dermis/patología , Módulo de Elasticidad/fisiología , Epidermis/diagnóstico por imagen , Epidermis/patología , Humanos , Nevo Pigmentado/diagnóstico por imagen , Lesiones Precancerosas/diagnóstico por imagen , Lesiones Precancerosas/patología , Piel/diagnóstico por imagen , Neoplasias Cutáneas/diagnóstico por imagen , Tomografía de Coherencia Óptica/métodos , Interfaz Usuario-Computador , Vibración
19.
J Sports Sci ; 37(8): 911-920, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30369285

RESUMEN

This randomised controlled trial investigated changes in eccentric hamstring strength, 10m sprint speed, and change-of-direction (COD) performance immediately post Nordic hamstring curl (NHC) intervention and following a 3-week detraining period. Fourteen male team sports athletes were randomised to a do-as-usual control group (CG; n = 7) or to a NHC intervention group (NHC; n = 7). Isokinetic dynamometry at 180°/s evaluated eccentric hamstring strength immediately post-intervention as the primary outcome measure. Secondary outcomes included 10 m sprint time and COD. Each outcome was measured, pre, immediately post-intervention and following a 3-week detraining period. Immediately post-intervention significant group differences were observed in the NHC group for eccentric hamstring strength (31.81 Nm-1 vs. 6.44 Nm-1, P = 0.001), COD (-0.12 s vs. 0.20 s; P = 0.003) and sprint (- 0.06 s vs. 0.05 s; P = 0.024) performance. Performance improvements were maintained following a detraining period for COD (-0.11 s vs. 0.20 s; P = 0.014) and sprint (-0.05 s vs. 0.03 s, P = 0.031) but not eccentric hamstring strength (15.67 Nm-1 vs. 6.44 Nm-1, P = 0.145) These findings have important implications for training programmes designed to reduce hamstring injury incidence, whilst enhancing physical qualities critical to sport.


Asunto(s)
Adaptación Fisiológica , Rendimiento Atlético/fisiología , Músculos Isquiosurales/fisiología , Fuerza Muscular , Entrenamiento de Fuerza/métodos , Carrera/fisiología , Adolescente , Adulto , Músculos Isquiosurales/lesiones , Humanos , Masculino , Destreza Motora/fisiología , Acondicionamiento Físico Humano , Método Simple Ciego , Esguinces y Distensiones/prevención & control , Adulto Joven
20.
J Sports Sci ; 37(12): 1338-1346, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30563419

RESUMEN

The aim of the current study was to investigate positional specific physical performance and external load responses to short term fixture congestion in English professional soccer. A total of 515 match observations were categorised as G1: the first game in a week with >4 days following a previous game, G2: the second game in a week played <4 days since G1, and G3: the third game in a week played with <4 days between each of the previous games. Global positioning system and accelerometer-based metrics were partitioned into fifteen-minute epochs. These data were then analysed using a linear mixed model to assess both the within and between game positional differences. Total, low-intensity (<4.0 m·s-1), medium-intensity (MID; 4.0-5.5 m·s-1), and sprint distance (>7.0 m·s-1) were significantly different across games. No between game positional differences were identified; however, within match position specific differences were observed for measures of MID and HID. No significant differences were evident for accelerometer derived metrics between games or across positions. The current data suggests that the use of fifteen minute within game epochs enables the detection of alterations in physical output during congested schedules. The observed within game positional differences has implications for player specific conditioning and squad rotation strategies.


Asunto(s)
Rendimiento Atlético/fisiología , Carrera/fisiología , Fútbol/fisiología , Adulto , Conducta Competitiva , Inglaterra , Sistemas de Información Geográfica , Humanos , Modelos Lineales , Masculino , Adulto Joven
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