Top-class women's soccer performance: peak demands and distribution of the match activities relative to maximal intensities during official matches.

The aims of the current study were to determine the most demanding passages of match play (MDP) and the distribution of match activities relative to maximum intensities during official matches in top-class women soccer players. Twenty-eight women players competing in European championship and international UEFA competitions were monitored during 38 official matches (277 individual samples). Maximum relative (m · min-1) total distance (TD), high-speed running (HSRD), very high-speed running (VHSRD), sprint, acceleration and deceleration distances were calculated across different durations (1-5, 10, 15, 90 min) using a rolling average analysis. Maximum intensities (1-minpeak) were used as the reference value to determine the distribution of relative intensity across the whole-match demands (90-minavg). Time and distance higher than 90-minavg (> 90-minavg) were also calculated. MDP showed moderate to very large [effect size (ES): 0.63/5.20] differences between 1-minpeak vs all durations for each parameter. The relative (m · min-1) 1-minpeak was greater than 90-minavg of about +63% for TD, +358% for HSRD, +969% for VHSRD, +2785% for sprint, +1216% for acceleration, and +768% for deceleration. The total distance covered > 90-minavg was ~66.6% of the total distance covered during the 90-minavg for TD, ~84.8% for HSRD, ~97.4% for VHSRD, ~100% for sprint, ~99.1% for acceleration and ~98.2% for deceleration. The relative distance > 90-minavg was higher (P < 0.05) than the 90-minavg for each metric (ES: 2.22 to 7.58; very large). The present results may help coaches and sport scientists to replicate the peak demands during training routine in top-class women soccer players.

Isolated distal grade III lateral collateral ligament injury: what is the real clinical impact in professional athletes?

The isolated III grade lateral collateral ligament injuries are rare, and there is limited literature available on their management. We report 3 cases of professional soccer players with isolated distal lateral collateral ligament III grade injury, confirmed by MRI studies. After undergoing MRI examinations, all three players resumed competitive activity without resting and experienced no consequences regarding joint stability. We assessed the significance of the lateral collateral ligament in providing lateral stabilization to the knee joint in professional footballers with clinical tears of the lateral collateral ligament. The other structures of posterolateral area that remain intact contribute to joint stability, and the lateral collateral ligament's extra-articular position appears to expedite the ligament's healing process. Therefore, we propose a possible conservative treatment approach, mostly for professional athletes and adolescent patients, involving a rehabilitation plan without the need for surgery.

Are Football Players More Prone to Muscle Injury after COVID-19 Infection? The "Italian Injury Study" during the Serie a Championship.

INTRODUCTION: Football was the first sport to resume competitions after the coronavirus disease 2019 (COVID-19) lockdown and promptly the hypothesis was raised of a potential relationship between the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and musculoskeletal injuries in athletes. This study aimed to confirm the association between SARS-CoV-2 infection and muscle strain injury in a large population of elite football players and to investigate if the COVID-19 severity level could affect the risk of injury. METHODS: A retrospective cohort study involving 15 Italian professional male football teams was performed during the Italian Serie A 2020-2021 season. Injuries and SARS-CoV-2 positivity data were collected by team doctors through an online database. RESULTS: Of the 433 included players, we observed 173 SARS-CoV-2 infections and 332 indirect muscle strains. COVID-19 episodes mostly belonged to severity level I and II. The injury risk significantly increased after a COVID-19 event, by 36% (HR = 1.36, CI95% 1.05; 1.77, p-value = 0.02). The injury burden demonstrated an 86% increase (ratio = 1.86, CI95% 1.21; 2.86, p-value = 0.005) in the COVID-19 severity level II/III versus players without a previous SARS-CoV-2 infection, while level I (asymptomatic) patients showed a similar average burden (ratio = 0.92, CI95% 0.54; 1.58, p-value = 0.77). A significantly higher proportion of muscle-tendon junction injuries (40.6% vs. 27.1%, difference = 13.5%, CI95% 0.002%; 26.9%, p-value = 0.047) was found when comparing level II/III versus Non-COVID-19. CONCLUSIONS: This study confirms the correlation between SARS-CoV-2 infection and indirect muscle injuries and highlights how the severity of the infection would represent an additional risk factor.

Indirect Rectus Femoris Injury Mechanisms in Professional Soccer Players: Video Analysis and Magnetic Resonance Imaging Findings.

OBJECTIVE: To describe injury mechanisms and magnetic resonance imaging (MRI) findings in acute rectus femoris (RF) injuries of soccer players using a systematic video analysis. DESIGN: Descriptive case series study of consecutive RF injuries from November 2017 to July 2022. SETTING: Two specialized sports medicine hospitals. PARTICIPANTS: Professional male soccer players aged between 18 and 40 years, referred for injury assessment within 7 days after a RF injury, with an available video footage of the injury and a positive finding on an MRI. INDEPENDENT VARIABLES: Rectus femoris injury mechanisms (specific scoring based on standardized models) in relation to RF muscle injury MRI findings. MAIN OUTCOME MEASURES: Rectus femoris injury mechanism (playing situation, player/opponent behavior, movement, and biomechanics), location of injury in MRI. RESULTS: Twenty videos of RF injuries in 19 professional male soccer players were analyzed. Three different injury mechanisms were seen: kicking (80%), sprinting (10%), and change of direction (10%). Isolated single-tendon injuries were found in 60% of the injuries. Of the kicking injuries, 62.5% included complete tendon ruptures, whereas both running injuries and none of the change of direction injuries were complete ruptures. The direct tendon was involved in 33% of the isolated injuries, and the common tendon was affected in all combined injuries. CONCLUSIONS: Rectus femoris injuries typically occur during kicking among football players. Most of the RF injuries involve a complete rupture of at least one tendon. Kicking injuries can also affect the supporting leg, and sprinting can cause a complete tendon rupture, whereas change of direction seems not to lead to complete ruptures.

Paramagnetic contrast medium in high-level athletes with lower limb muscle injuries: can it make the return to sport safer reducing the recurrence rate?

PURPOSE: The aim is to investigate whether contrast medium can improve accuracy in the assessment of healing muscle injury in high-level professional athletes. MATERIALS AND METHODS: Our series is a retrospective study including the records of 22 players (mean age 28 ± 5 SD) with lower limbs muscle injuries type 3a (Mueller-Wohlfarth). All athletes received two MRIs: the day after the injury and before resuming heavy effort activities. Contrast medium uptake was measured in the second MRI by comparing the mean enhancement at the lesion site (ME) with that of the healthy contralateral muscle (HM). The result is a percentage referred to as muscular contrast index (MC index). The difference between the mean MC index value between athletes with and without re-injury was assessed with both the Mann-Whitney and the Kruskal-Wallis test. RESULTS: Twenty-nine muscle injuries matched the inclusion criteria. The mean MC index values, adjusted for the variable of time elapsed between the last contrast examination and return to the field, were significantly different in the two study groups (p < .001). CONCLUSION: The contrast medium in the follow-up of muscle injuries may be useful in determining the degree of scar stability in a healing injury. Injuries with a high MC index were found to be 'unstable', with a higher rate of recurrence than those with a low MC index. Resumption of competitive activity after achieving not only clinical resolution but also a satisfactory MC index value may increase the safety of return to the field and reduce the recurrence rate.

Management of anterior thigh injuries in soccer players: practical guide.

Most of the anterior thigh injuries are contusions or strains, however, some of these injuries can be career ending. Early diagnosis and correct treatment are key to successful outcome. Analyzing injury mechanism and adding both clinical and imaging findings, clinicians can make the right treatment decisions already often in the acute phase of the injury. Low grade contusions and muscle strains are treated well with planned rehabilitation, but complete tendon injuries or avulsions can require operative treatment. Also, neglected minor injuries could lead to chronic disabilities and time lost from play. Typical clinical presentation of anterior thigh injury is swelling and pain during hip flexion or knee extension. In more severe cases a clear gap can be palpated. Imaging methods used are ultrasound and magnetic resonance imaging (MRI) which are helpful for clinicians to determine more exact the extent of injury. MRI can identify possible tendon retractions which may need surgery. Clinicians should also be aware of other traumatic lesions affecting anterior thigh area such as myositis ossificans formation. Optimal treatment should be coordinated including acute phase treatment with rest, ice, and compression together with designed return-to-play protocol. The anatomical structure involved lines the treatment pathway. This narrative review describes these more common reasons for outpatient clinical visits for anterior thigh pain and injuries among soccer players.

Proximal Adductor Longus Tendon Repair With a Concomitant Distal Fascial Release for Complete Hip Adductor Tendon Tears: Surgical Technique and Outcomes in 40 Male Athletes.

BACKGROUND: The optimal treatment for complete avulsions of the proximal adductor longus (AL) is still debatable, and different operative and nonoperative treatment options have been suggested. PURPOSE: To report surgical techniques and functional outcomes of a series of athletes who were treated operatively for proximal AL tears. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A retrospective evaluation of patients who underwent surgical repair of complete proximal AL tear with concomitant distal fascial release with or without lesions of the neighboring soft tissue structures was performed. This included preinjury Tegner score, age, number of tendons involved, time interval from injury to surgery, and postoperative complications. Self-reported outcomes were defined based on the ability to regain sports activities (excellent, good, moderate, fair, or poor). Between-group comparisons were performed to identify factors associated with improved outcomes. The Mann-Whitney nonparametric test was used for comparing continuous variables, and the Fisher exact test was used for comparing nominal variables. RESULTS: A total of 40 male athletes were included in the evaluation, with an average follow-up of 11 months (range, 6 months-8 years). Self-reported outcome was excellent in 23 (57.5%), good in 13 (32.5%), and moderate in 4 (10%) patients. Comparisons between patients with excellent versus good/moderate outcomes revealed nonsignificant differences regarding age at injury and preinjury Tegner score. Athletes with excellent outcomes received surgery sooner after the injury compared with athletes with good/moderate outcomes (2.4 ± 1.8 vs 11.4 ± 11.0 weeks, respectively; P < .01). CONCLUSION: Surgical repair for complete proximal AL tears with a concomitant distal fascial release resulted in outcomes rated as good or excellent in 90% of the cases. This treatment should be considered particularly in high-level athletes with a clear tendon retraction and within the first month after the injury. Further research is nevertheless needed to compare these outcomes with other treatment alternatives to better define criteria advocating surgery.

Role of ultrasound and magnetic resonance imaging in the prognosis and classification of muscle injuries in professional football players: correlation between imaging and return to sport time.

PURPOSE: To study distractive muscle injuries applying US and MRI specific classifications and to find if any correlation exists between the results and the return to sport (RTS) time. The second purpose is to evaluate which classification has the best prognostic value and if the lesions extension correlates with the RTS time. METHODS: A total of 26 male, professional soccer players (age 21.3 ± 5.6), diagnosed with traumatic muscle injury of the lower limbs, received ultrasound and MRI evaluation within 2 days from the trauma. Concordance between US and MRI findings was investigated. The relationships between MRI and US based injury grading scales and RTS time were evaluated. Correlation between injuries' longitudinal extension and RTS time was also investigated. RESULTS: The correlation between US and MRI measurements returned a Spearman value of rs = 0.61 (p = .001). Peetrons and Mueller-Wohlfahrt grading scales correlations with RTS time were r = 0.43 (p = .02) and r = 0.83 (p = < .001). The lesion's extension correlation with RTS time was r = 0.63 (p < .001). The correlation between the site of the lesion and its location with the RTS time were rs = 0.2 and rs = 0.25. CONCLUSIONS: Both US and MRI can be used as prognostic indicators along with the Peetrons (US) and the Mueller-Wohlfahrt (MRI) classifications. MRI is more precise and generates more reproducible results. The lesion craniocaudal extension must be considered as a prognostic indicator, while the injury location inside the muscle or along its major axis has doubtful significance.

Multicolor Immunofluorescence Staining of Paraffin-Embedded Human Bone Marrow Sections.

Immunofluorescence is an indispensable method for the identification, localization and study of the expression of target antigens in formalin-fixed, paraffin-embedded (FFPE) tissue sections of human bone marrow. However, the procedure shows technical limitations because of the chemical and physical treatments required for sample processing before imaging. Here we describe a revisited protocol to obtain high-resolution images of human bone marrow trephine biopsies, improving the antigen-antibody recognition and preserving the morphology and the architecture of the bone marrow microenvironment.

Incidence of injuries in young soccer players: epidemiological study in an Italian elite club.

BACKGROUND: Football is the most popular sport in the world, increasingly played by the youngsters. However, little epidemiological data exists regarding injuries in young players. The aim of this study was to describe the most common types and sites of injury among the different classes of a single professional football club. METHODS: The present perspective study covered a three-season period, including 679 children divided in 9 age classes. All the athletes were managed by the same staff and for each injury, onset date, date of return to training, anatomic site and type of injury were recorded. RESULTS: The mean age of the population was 12.7 years old (Range 7.4-16.9). A total 975 injuries were recorded without significant differences among seasons (P=0.682). The most affected classes were U17 and U16, while the lowest rate of injury was in U11. The most common injury in U9 and U10 affected foot and ankle, while in all the other classes thigh was the most frequently site involved. Focusing on the type of injury, the most common cause was traumatic (40.9%), followed by muscular diseases. The mean value of absence from soccer was 19.7 days (±1.2). The highest rate of injuries occurred in September and August. In January and February, injuries were more frequent during competitions, whereas in the other months the rate was inverted. CONCLUSIONS: This study highlights that preseason and the final phase of the season are more at risk of injury and the type of injury differs between classes.

High NESTIN Expression Marks the Endosteal Capillary Network in Human Bone Marrow.

Hematopoiesis is hosted, supported and regulated by a special bone marrow (BM) microenvironment known as "niche." BM niches have been classified based on micro-anatomic distance from the bone surface into "endosteal" and "central" niches. Whilst different blood vessels have been found in both BM niches in mice, our knowledge of the human BM architecture is much more limited. Here, we have used a combination of markers including NESTIN, CD146, and αSMA labeling different blood vessels in benign human BM. Applying immunohistochemical/immunofluorescence techniques on BM trephines and performing image analysis on almost 300 microphotographs, we detected high NESTIN expression in BM endothelial cells (BMECs) of small arteries (A) and endosteal arterioles (EA), and also in very small vessels we named NESTIN+ capillary-like tubes (NCLTs), not surrounded by sub-endothelial perivascular cells that occasionally reported low levels of NESTIN expression. Statistically, NCLTs were detected within 40 µm from bone trabecula, frequently found in direct contact to the bone line and spatially correlated with hematopoietic stem/progenitor cells. Our results support the expression of NESTIN in human BMECs of EA and A in accordance with the updated classification of murine BM micro-vessels. NCLTs for their peculiar characteristics and micro-anatomical localization have been here proposed as transitional vessels possibly involved in regulating human hematopoiesis.

Evaluation of muscle tears in professional athletes using diffusion-weighted imaging and apparent diffusion coefficient: preliminary results.

PURPOSE: Many studies have evaluated the role of DWI in musculoskeletal diseases but less is known on muscle tears. Especially for professional athletes, muscle injuries are responsible for large time lost. The aim of this study was to investigate on potential relationship between the muscle tear degree and the diffusion characteristics. METHODS: In this retrospective study, patients signed a comprehensive consent form according to Good Clinical Practice guidelines before proceeding with all examinations. It satisfied all the requirements of the Declaration of Helsinki and the Italian national law for the protection of personal data. We have analyzed 38 professional athletes (36 males; mean age±standard deviation 27±8 years) with a muscle tear. They were 26 football and 12 athletics players, with clinically suspected injuries of the lower limbs muscles. All of patients underwent a 1.5-T MRI with standard protocol (STIR, TSE T2, SE T1, PD T2, PD fat sat T2) plus the DWI sequences with 0, 400 and 800 B-values (s/mm2). Per each B value, an experienced radiologist measured the signal intensity (SI, in arbitrary units [au]) using a region of interest (ROI) placed within the tear on DWI images. SI drop off at the third B value was calculated referred to the first B value. Similarly, ADC was measured using the ADC map in a small ROI within the tear. Bivariate associations were evaluated using the Student t test. Logistic regression was performed using the tear degree as dependent variable. Data were given as mean±standard deviation. RESULTS: According the Muller-Wohlfarth classification, the 38 muscle tears were classified in type 3a in 22/38 cases and 3b in 16/38 cases. At bivariate analysis, 3a-tears had a SI at the third B value (24±9 au) lower (P=0.003) than that of 3b-tears (34±9 au). Similarly, 3a-tears had a SI drop off (73±10%) lower (P=0.008) than that of 3b-tears (82±9%). ADC was not significantly associated to tear degree (P=0.093). At regression analysis, SI at the third B value was the only independent predictor of the tear degree (P=0.032), while the SI drop off was borderline significant (P=0.070). CONCLUSION: This preliminary data showed a positive correlation between the degree of muscle tears and the SI at the third B-value. Compared to 3a- tears, 3b-tears tend to show higher SI and a higher SI drop off.

Increased level of DNA damage in some organs of obese Zucker rats by γ-H2AX analysis.

In a recent study, we showed that lymphocytes of obese Italian children/adolescents displayed levels of double strand breaks (DSB), assayed as serine 139-phosphorylated histone H2AX (γ-H2AX), about eightfold higher than normal weight controls, and that 30% of this damage-generated micronuclei. These findings suggested that obese children could be at increased risk of obesity-mediated cancer later in life. We therefore aimed to assess the level of γ-H2AX in a genetic animal model of obesity (Zucker rat) to identify a genotoxic/carcinogenic risk in some organs. The DSB marker was studied in 3- to 4-week-old rats and in 9- to 13-week-old rats. Paraffin-embedded sections of heart, thyroid, liver, pancreas, lung, kidney, esophagus, and gut from the fa-/fa- (obese) and the fa+/fa- (lean) control animals were processed for immunohistochemistry detection of γ-H2AX. Pancreas (0.0624 ± 0.0195), lung (0.1197 ± 0.0217), esophagus (0.1230 ± 0.0351), kidney (0.1546 ± 0.0149), and gut (0.1724 ± 0.0352) of 9- to 13-week-old obese rats showed a higher proportion of γ-H2AX-positive nuclei, than their lean counterparts (0.0092 ± 0.0033, 0.0416 ± 0.0185, 0.0368 ± 0.0088, 0.0686 ± 0.0318, and 0.0703 ± 0.0239, respectively). No difference was seen in the 3- to 4-week-old age group with regard to obesity, indicating that the DNA damage increased with older age of the rats. We hypothesize that the organs of the obese animals showing high levels of DSB could represent target tissues for the development of obesity-related cancers. Environ. Mol. Mutagen. 58:477-484, 2017. © 2017 Wiley Periodicals, Inc.

Human adult mesangiogenic progenitor cells reveal an early angiogenic potential, which is lost after mesengenic differentiation.

BACKGROUND: Mesangiogenic progenitor cells (MPCs) have shown the ability to differentiate in-vitro toward mesenchymal stromal cells (MSCs) as well as angiogenic potential. MPCs have so far been described in detail as progenitors of the mesodermal lineage and appear to be of great significance in tissue regeneration and in hemopoietic niche regulation. On the contrary, information regarding the MPC angiogenic process is still incomplete and requires further clarification. In particular, genuine MPC angiogenic potential should be confirmed in-vivo. METHODS: In the present article, markers and functions associated with angiogenic cells have been dissected. MPCs freshly isolated from human bone marrow have been induced to differentiate into exponentially growing MSCs (P2-MSCs). Cells have been characterized and angiogenesis-related gene expression was evaluated before and after mesengenic differentiation. Moreover, angiogenic potential has been tested by in-vitro and in-vivo functional assays. RESULTS: MPCs showed a distinctive gene expression profile, acetylated-low density lipoprotein uptake, and transendothelial migration capacity. However, mature endothelial markers and functions of endothelial cells, including the ability to form new capillaries, were absent, thus suggesting MPCs to be very immature endothelial progenitors. MPCs showed marked 3D spheroid sprouting activating the related molecular machinery, a clear in-vitro indication of early angiogenesis. Indeed, MPCs applied to chicken chorioallantoic membrane induced and participated in neovessel formation. All of these features were lost in mesengenic terminally differentiated P2-MSCs, showing definite separation of the two differentiation lineages. CONCLUSION: Our results confirm the bona-fide angiogenic potential of MPCs and suggest that the high variability reported for MSC cultures, responsible for the controversies regarding MSC angiogenic potential, could be correlated to variable percentages of co-isolated MPCs in the different culture conditions so far used.

Transcriptional alterations of ET-1 axis and DNA damage in lung tissue of a rat obesity model.

Obesity has been implicated in the development of many cancers. This can lead to genome damage, especially in the form of double-strand break, the presence of which is now easily detected through nuclear phosphorylation of histone H2AX (γ-H2AX) focus assay. Recently, the endothelin (ET) axis has also been shown to have a role in the growth and progression of several tumors, including lung cancer. The aim of this study was to evaluate the ET-1 system transcriptional alterations and γ-H2AX in lung tissue of Zucker rats subdivided into obese (O, n=22) and controls (CO, n=18) rats: under either fasting conditions (CO(fc)-O(fc)) or acute hyperglycemia (CO(AH)-O(AH)). Significantly higher prepro-ET-1 (p=0.05) and ET-converting enzyme (ECE)-2 mRNA expression was observed in O with respect to CO. A significant positive association was observed between prepro-ET-1 and ET-A in the whole rat population (p=0.009) or in the obese group alone (p=0.007). The levels of γ-H2AX in O and in O(AH) rats were significantly higher (p=0.019) than in the corresponding CO and CO(AH) rats (p=0.038). The study shows an inappropriate secretion of ET-1 in O animals with a parallel DNA damage in their lungs, providing novel mechanisms by which ET receptor antagonist may exert organ protection.

Colloidal aggregation in microgravity by critical Casimir forces.

By using the critical Casimir force, we study the attractive strength dependent aggregation of colloids with and without gravity by means of near field scattering. Significant differences were seen between microgravity and ground experiments, both in the structure of the formed fractal aggregates as well as in the kinetics of growth. In microgravity purely diffusive aggregation is observed. By using the continuously variable particle interaction potential we can for the first time experimentally relate the strength of attraction between the particles and the structure of the aggregates.

Thermal fluctuations in a layer of liquid CS2 subjected to temperature gradients with and without the influence of gravity.

We report data for nonequilibrium density fluctuations in a layer of liquid CS(2) subjected to temperature gradients on Earth and in a satellite. The structure factor S(q) was measured using a calibrated shadowgraph. Upon removing gravity, S(q) increased dramatically at small wave vector, until the fluctuations generated by thermal noise were limited only by the 3 mm sample thickness. The results agree with theory to within a few percent on Earth and are ∼14% below theory in microgravity, demonstrating that the use of equilibrium Langevin forces is appropriate in this nonequilibrium situation.

Fractal fronts of diffusion in microgravity.

Spatial scale invariance represents a remarkable feature of natural phenomena. A ubiquitous example is represented by miscible liquid phases undergoing diffusion. Theory and simulations predict that in the absence of gravity diffusion is characterized by long-ranged algebraic correlations. Experimental evidence of scale invariance generated by diffusion has been limited, because on Earth the development of long-range correlations is suppressed by gravity. Here we report experimental results obtained in microgravity during the flight of the FOTON M3 satellite. We find that during a diffusion process a dilute polymer solution exhibits scale-invariant concentration fluctuations with sizes ranging up to millimetres, and relaxation times as large as 1,000 s. The scale invariance is limited only by the finite size of the sample, in agreement with recent theoretical predictions. The presence of such fluctuations could possibly impact the growth of materials in microgravity.

Repeated-sprint ability in professional and amateur soccer players.

This study investigated the repeated-sprint ability (RSA) physiological responses to a standardized, high-intensity, intermittent running test (HIT), maximal oxygen uptake (VO(2) (max)) and oxygen uptake (VO(2)) kinetics in male soccer players (professional (N = 12) and amateur (N = 11)) of different playing standards. The relationships between each of these factors and RSA performance were determined. Mean RSA time (RSA(mean)) and RSA decrement were related to the physiological responses to HIT (blood lactate concentration ([La(-)]), r = 0.66 and 0.77; blood bicarbonate concentration ([HCO(3)-]), r = -0.71 and -0.75; and blood hydrogen ion concentration ([H(+)]), r = 0.61 and 0.73; all p < 0.05), VO(2) (max) (r = -0.45 and -0.65, p < 0.05), and time constant (tau) in VO(2) kinetics (r = 0.62 and 0.62, p < 0.05). VO(2) (max) was not different between playing standards (58.5 +/- 4.0 vs. 56.3 +/- 4.5 mL.kg(-1).min(-1); p = 0.227); however, the professional players demonstrated better RSA(mean) (7.17 +/- 0.09 vs. 7.41 +/- 0.19 s; p = 0.001), lower [La-] (5.7 +/- 1.5 vs. 8.2 +/- 2.2 mmol.L(-1); p = 0.004), lower [H+] (46.5 +/- 5.3 vs. 52.2 +/- 3.4 mmol.L(-1); p = 0.007), and higher [HCO3-] (20.1 +/- 2.1 vs. 17.7 +/- 1.7 mmol.L(-1); p = 0.006) after the HIT, and a shorter in VO2 kinetics (27.2 +/- 3.5 vs. 32.3 +/- 6.0 s; p = 0.019). These results show that RSA performance, the physiological response to the HIT, and differentiate between professional- and amateur-standard soccer players. Our results also show that RSA performance is related to VO(2) max, tau, and selected physiological responses to a standardized, high-intensity, intermittent exercise.

Mutual Voronoi tessellation in spoke pattern convection.

Planar cellular networks are made of polygonal cells usually having an average of six sides and trivalent vertices. We analyze the topological properties of spoke patterns observed in the convection of highly viscous fluids. The competition between ascending and descending columns of fluid generates dual networks where on average cells are four sided and vertices tetravalent. This observation identifies a new class of dual networks satisfying a mutual Voronoi relation. The metric of the pattern is dominated by the distance between nearest neighbors vertices of opposite species.