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Stretching has long been used in many physical activities to increase range of motion (ROM) around a joint. Stretching also has other acute effects on the neuromuscular system. For instance, significant reductions in maximal voluntary strength, muscle power or evoked contractile properties have been recorded immediately after a single bout of static stretching, raising interest in other stretching modalities. Thus, the effects of dynamic stretching on subsequent muscular performance have been questioned. This review aimed to investigate performance and physiological alterations following dynamic stretching. There is a substantial amount of evidence pointing out the positive effects on ROM and subsequent performance (force, power, sprint and jump). The larger ROM would be mainly attributable to reduced stiffness of the muscle–tendon unit, while the improved muscular performance to temperature and potentiation-related mechanisms caused by the voluntary contraction associated with dynamic stretching. Therefore, if the goal of a warm-up is to increase joint ROM and to enhance muscle force and/or power, dynamic stretching seems to be a suitable alternative to static stretching. Nevertheless, numerous studies reporting no alteration or even performance impairment have highlighted possible mitigating factors (such as stretch duration, amplitude or velocity). Accordingly, ballistic stretching, a form of dynamic stretching with greater velocities, would be less beneficial than controlled dynamic stretching. Notwithstanding, the literature shows that inconsistent description of stretch procedures has been an important deterrent to reaching a clear consensus. In this review, we highlight the need for future studies reporting homogeneous, clearly described stretching protocols, and propose a clarified stretching terminology and methodology.

BRD4, a major tandem-bromodomain-containing transcription regulator, has two isoforms. The long isoform (BRD4L) has an extended C terminus that binds transcription cofactors, while the short isoform (BRD4S) lacks this C-terminal extension. Unlike BRD4L, the role of BRD4S in gene transcription remains unclear. Here, we report that, in human cancer cells, BRD4S forms nuclear puncta that possess liquid-like properties and that colocalize with BRD4L, MED1 and sites of histone H3 lysine 27 acetylation. BRD4 puncta are correlated with BRD4S but not BRD4L expression levels. BRD4S knockdown reduces BRD4S condensation, and ectopic expression promotes puncta formation and target gene transcription. BRD4S nuclear condensation is mediated by its intrinsically disordered regions and binding of its bromodomains to DNA and acetylated chromatin, respectively, and BRD4S phosphorylation diminishes BRD4 condensation. Our study illuminates a previously unappreciated role of BRD4S in organizing chromatin and transcription factors through phase separation to sustain gene transcription in chromatin for cancer cell proliferation.A combination of cellular, in vitro phase separation and functional assays shows that the intrinsically disordered regions and bromodomains of the BRD4 short isoform induce formation of liquid-like condensates in cancer cell nuclei and enhance transcriptional activity.

The aims of this study in elite youth French players were to 1) describe the anthropometric and physical characteristics of international and non-international players from U16 to U20, and 2) compare these characteristics across age categories and playing standard (international or non-international). Altogether, 1423 players from the French Rugby Federation’s academies participated in a physical testing battery, part of its national young player development pathway. From seasons 2010 to 2020, players were assessed for anthropometric (body mass and height), off-field (bench press; isometric squat, vertical jump) and on-field physical characteristics (aerobic capacity: maximal aerobic speed [MAS]; speed: 10-m, 50-m sprint). A 2-way mixed model analysis of variance (ANOVA) was used to compare physical characteristics across age categories and playing standards. Two separate models were used for forwards and backs. A main statistical effect was observed for age category and playing standard (range p < 0.05 –p < 0.001). Pair-wise category comparisons showed that older players were generally taller, heavier, stronger, faster and demonstrated better aerobic qualities than younger peers. The same results were observed for INT compared with NI players while INT forwards were also taller and heavier than NI peers (range p < 0.01 –p < 0.001). Findings revealed a clear progression in anthropometric characteristics and physical qualities throughout the age development pathway in elite young French rugby players. Findings also identified certain physical qualities (strength, power and speed) necessary at younger levels to achieve international standard.

Weekly training loads are typically reported using absolute values and are not individualized according to competition positional demands (relative values). The aim of this study was to evaluate absolute and relative training loads and compare across playing positions during a full in-season in an elite soccer academy. 24 elite academy soccer players, categorized into five positions (CD: central defender [n = 4]; FB: full back [n = 5]; CM: central midfielder [n = 6]; WM: wide midfielder [n = 5]; FW: forward [n = 4]), were monitored using a global positioning system. Absolute training load was calculated using the total distance, the distance at moderate-speed ([15-20[ km·h-1), high-speed ([20-25[ km·h-1), sprint (> 25 km·h-1), the total number of accelerations (> 3 m·s-2) and decelerations (< -3 m·s-2). Relative training load was calculated by dividing absolute training loads by mean values from the competitive matches. Training loads were determined daily according to their distance from match day (MD). One-way ANOVAs were performed to evaluate differences between playing positions. Absolute moderate-speed distance was greater for WM compared to CD (p = 0.015, and p = 0.017), while the opposite was shown for relative values (p = 0.014, and p < 0.001) on MD-4 and MD-3, respectively. The absolute moderate-speed distance was not different between CD, FB, CM, and FW, whereas relative values were greater for CD on MD+2 and MD-4 (p < 0.05). FB and WM performed greater absolute high-speed distance than CD on MD-4 and MD-3 (p < 0.05) while no difference was highlighted for relative values.Our results demonstrated that in the present academy players, training load for CD was underestimated using absolute training loads for moderate and high-speed distances. In contrast, relative training loads highlighted WM as an underloaded position. Therefore, relative training loads are recommended as they contextualize training loads according to competitive demands and favor training individualization.

Our study aimed to combine psychological and physical factors to explore the impact of the menstrual cycle on performance in elite academy women soccer players through weekly monitoring. Eighteen elite academy women soccer players were monitored. Players reported daily through an online anonymous survey if they were in menstruation. Players answered the Hooper Questionnaire daily, performed an Illinois Agility Test (IAT) twice a week, and rated their perceived exertion (RPE) after every training session. Tests were associated with a complete menstrual cycle reported through the online anonymous survey to determine the two weeks of the follicular phase and the two weeks of the luteal phase. Of the 18 players, 10 completed all requirements and were retained for analyses. IAT did not show significant differences throughout the menstrual cycle (p = 0.633). Fatigue (p = 0.444), Stress (p = 0.868), Sleep (p = 0.398), DOMS (delayed onset muscle soreness; p = 0.725), and Hooper Index (p = 0.403) did not show significant differences either. RPE was also comparable across the cycle (p = 0.846). Our results failed to demonstrate that hormonal variation during the menstrual cycle influenced psychological and physical markers of performance.

This study aimed to compare the effects of passive and active warm-up protocols combined with static or neurodynamic stretching on hamstring muscle function. Sixteen individuals (7 men and 9 women) performed three experimental sessions in a randomized order: 1) passive warm-up and static stretching, 2) passive warm-up and neurodynamic stretching, 3) active warm-up and static stretching (control condition). Passive warm- up consisted of 20 minutes in a 45°C hot-room. Active warm-up included 10 minutes of cycling and 10 minutes of sub-maximal contractions. Following warm-up, the participants were engaged in six sets of 30-second stretches, either performed using static or neurodynamic modalities. Testing involved two maximal voluntary contractions (MVC), a passive knee extension test (to evaluate range of motion and hamstring stiffness), and a stand-and-reach test (used for flexibility assessment) conducted before, after warm-up, and after stretching. Electromyography from the biceps femoris and semitendinosus were recorded during MVC. Results revealed a significant time effect for flexibility (p < 0.001). Flexibility enhancements were obtained following active and passive warm-ups and further increased after the stretch, independently of the stretch intervention. The electromyographic activity of the semitendinosus muscle was affected by the time (p = 0.004). It revealed a decrease after stretching as compared to a post-warm-up measurement. No other differences were observed between conditions and time for maximal torque and stiffness indexes. It is concluded that both the active and passive warm-up methods are efficient to increase flexibility. Irrespective of the modality, stretching further improved flexibility without any alteration in muscle viscoelastic properties.

This study aimed to apply different complexity-based methods to surface electromyography (EMG) in order to detect neuromuscular changes after realistic warm-up procedures that included stretching exercises. Sixteen volunteers conducted two experimental sessions. They were tested before, after a standardized warm-up, and after a stretching exercise (static or neuromuscular nerve gliding technique). Tests included measurements of the knee flexion torque and EMG of biceps femoris (BF) and semitendinosus (ST) muscles. EMG was analyzed using the root mean square (RMS), sample entropy (SampEn), percentage of recurrence and determinism following a recurrence quantification analysis (%Rec and %Det) and a scaling parameter from a detrended fluctuation analysis. Torque was significantly greater after warm-up as compared to baseline and after stretching. RMS was not affected by the experimental procedure. In contrast, SampEn was significantly greater after warm-up and stretching as compared to baseline values. %Rec was not modified but %Det for BF muscle was significantly greater after stretching as compared to baseline. The a scaling parameter was significantly lower after warm-up as compared to baseline for ST muscle. From the present results, complexity-based methods applied to the EMG give additional information than linear-based methods. They appeared sensitive to detect EMG complexity increases following warm-up.

RNA-protein interactions (RPIs) are promising targets for developing new molecules of therapeutic interest. Nevertheless, challenges arise from the lack of methods and feedback between computational and experimental techniques during the drug discovery process. Here, we tackle these challenges by developing a drug screening approach that integrates chemical, structural and cellular data from both advanced computational techniques and a method to score RPIs in cells for the development of small RPI inhibitors; and we demonstrate its robustness by targeting Y-box binding protein 1 (YB-1), a messenger RNA-binding protein involved in cancer progression and resistance to chemotherapy. This approach led to the identification of 22 hits validated by molecular dynamics (MD) simulations and nuclear magnetic resonance (NMR) spectroscopy of which 11 were found to significantly interfere with the binding of messenger RNA (mRNA) to YB-1 in cells. One of our leads is an FDA-approved poly(ADP-ribose) polymerase 1 (PARP-1) inhibitor. This work shows the potential of our integrative approach and paves the way for the rational development of RPI inhibitors.

Even though the acute effects of pre-exercise static stretching and dynamic muscle activity on muscular and functional performance have been largely investigated, their effects on the corticospinal pathway are still unclear. For that reason, this study examined the acute effects of 5×20 s of static stretching, dynamic muscle activity and a control condition on spinal excitability, corticospinal excitability and plantar flexor neuromuscular properties. Fifteen volunteers were randomly tested on separate days. Transcranial magnetic stimulation was applied to investigate corticospinal excitability by recording the amplitude of the motor-evoked potential (MEP) and the duration of the cortical silent period (cSP). Peripheral nerve stimulation was applied to investigate (i) spinal excitability using the Hoffmann reflex (Hmax), and (ii) neuromuscular properties using the amplitude of the maximal M-wave (Mmax) and corresponding peak twitch torque. These measurements were performed with a background 30% of maximal voluntary isometric contraction. Finally, the maximal voluntary isometric contraction torque and the corresponding electromyography (EMG) from soleus, gastrocnemius medialis and gastrocnemius lateralis were recorded. These parameters were measured immediately before and 10 s after each conditioning activity of plantar flexors. Corticospinal excitability (MEP/Mmax) was significantly enhanced after static stretching in soleus (P = 0.001; ES = 0.54) and gastrocnemius lateralis (P<0.001; ES = 0.64), and after dynamic muscle activity in gastrocnemius lateralis (P = 0.003; ES = 0.53) only. On the other hand, spinal excitability (Hmax/Mmax), cSP duration, muscle activation (EMG/Mmax) as well as maximal voluntary and evoked torque remained unaltered after all pre-exercise interventions. These findings indicate the presence of facilitation of the corticospinal pathway without change in muscle function after both static stretching (particularly) and dynamic muscle activity.

Warm-up routines include various tasks focused on the peripheral contractile properties and nervous motor command. This present study was aimed at investigating the acute effects of different warm-up routines, emphasizing either peripheral (post-activation performance enhancement, PAPE) or central (motor imagery, MI) contributions on sport-specific tasks. Eleven young female athletes took part in this cross-over, randomized, controlled trial. They underwent three experimental sessions composed of a standardized warm-up followed by 10 min of (1) rest (CONTROL), (2) maximal concentric leg press (PAPE), or (3) mental repetitions of sprint tasks (MI). Post-tests consisted of reaction time, arrowhead agility test, 20 m sprint, repeated sprint ability, and NASA-TLX fatigue questionnaire. PAPE and MI significantly enhanced the arrowhead agility test (p < 0.001 and p = 0.012, respectively) and repeated sprint ability (p = 0.002 and p = 0.035, respectively) compared to CONTROL, without any difference between PAPE and MI. The 20 m sprint time was better after PAPE as compared to MI (p = 0.005) and CONTROL (p < 0.001), without any difference between MI and CONTROL. Reaction time and the NASA-TLX questionnaire were not affected by the warm-up modalities (p > 0.05). PAPE was the most efficient to optimize warm-up due to its greater peripheral contribution that would improve muscle contractility. MI specifically improved the imagined tasks mostly by central contribution.