Are physical performance and injury risk in a professional soccer team in match-play affected over a prolonged period of fixture congestion?

In this study, the effects of a prolonged period of fixture congestion (8 successive official matches in 26-days) on physical performance and injury risk and severity in a professional soccer team were investigated. Computerised motion-analysis was used to analyse the overall distance covered and that run at light- (0.0-11.0 km•h-1); low- (11.1-14.0 km•h-1); moderate- (14.1-19.7 km•h-1) and high-intensities (≥19.8 km•h-1) for the team as a whole. Distances were measured in metres per minute. Information on match injuries was recorded prospectively. The overall distance covered varied across successive matches (p<0.001) as more distance was run in games 4 and 7 compared to 2 and 3 respectively (126.6±12.3 m•min-1 and 125.0±13.2 m•min-1 vs. 116.0±8.0 m•min-1 and 115.5±11.0 m•min-1). Distance run in light-intensity exercise also varied (p<0.001) as more distance was covered in game 4 versus 1, 2, 3, 5 and 6 (75.5±3.8 m•min-1 vs. 70.6±2.4 m•min-1, 71.8±3.4 m•min-1, 69.3±2.6 m•min-1, 71.5±3.1 m•min-1, and 70.3±2.8 m•min-1) and in game 8 versus game 3 (73.1±3.8 vs. 69.3±2.6 m•min-1) respectively. When comparing match halves, there were no differences across games in overall or high-intensity distance covered and performance in these measures was similar for matches played before, during and after this period. Globally, no difference over the 8 games combined was observed between the reference team and opponents in any of the performance measures whereas the overall distance covered and that in low- (both p<0.001) and high-intensity running (p=0.040) differed in individual games. The incidence of match injury during the congested fixture period was similar to rates reported outside this period but the mean layoff duration of injuries was substantially shorter during the former (p<0.05). In summary, while the overall distance run and that covered at lower intensities varied across games, high-intensity running performance and injury risk were generally unaffected during a prolonged period of fixture congestion. These results might be linked to squad rotation and post-match recovery strategies in place at the present club

Are aerobic fitness and repeated sprint ability linked to fatigue in professional soccer match-play? A pilot study

This investigation examined the association between aerobic fitness and repeated sprint ability and match-related fatigue in 9 professional outfield soccer players. Aerobic fitness using maximal aerobic speed (MAS) was determined via a continuous progressive incremental running test conducted on a motorised treadmill. A repeated sprint ability test (6 successive 6 s sprints separated by 20 s passive recovery) was performed on a non-motorised treadmill to determine mean and best sprint times and a percentage decrement score (%PD). A total of 114 observations of physical performance derived using computerised time motion analyses were collected from 33 matches. Correlations between fitness test and match-play measures were examined for 1) accumulated fatigue: percentage difference between halves for total distance covered per minute, distance run at high-intensities (HIR, actions for 1s duration, >19.1 km/h) per minute, mean recovery time between high-intensity runs, and percentage difference between the distance covered in HIR in the first 5- and 15-minute periods versus the final 5- and 15-minute periods respectively in normal time; and for 2) transient fatigue: percentage difference between the distance covered in HIR in a peak 5-minute period and the subsequent 5-minute period and for the latter compared to the mean for all other 5-minute periods. No significant relationships were observed between MAS and fatigue scores (magnitude of associations: trivial to large). For mean and best sprint times and %PD, the only reported significant correlation (r=0.77, magnitude of association: very large, p<0.05) was between %PD and the % difference across halves for mean recovery time between high-intensity runs (magnitude of other associations: small to large). Criterion measures from tests of aerobic fitness and repeated sprint ability might not accurately depict a player’s capacity to resist fatigue during professional soccer competition

Squad management, injury and match performance in a professional soccer team over a Championship-winning season

Squad management, injury and physical, tactical and technical match performance were investigated in a professional soccer team across five consecutive league seasons (2008–2013, 190 league games) with specific focus on a championship-winning season (2010/11). For each player, match participation and time-loss injuries were recorded, the latter prospectively diagnosed by the team's physician. Defending and attacking tactical and technical performance indicators investigated included ball possession and possession in opponents' half, passes, forward passes, completed passes and forward passes, crosses and completed crosses, goal attempts and goal attempts on target, successful final third entries, free-kicks and 50/50 duels won/lost. Physical performance measures included total distance and distance covered at high-speeds (≥19.1 km/h). Results showed that during the 2010/11 season, squad utilisation was lowest potentially owing to the observed lower match injury occurrence and working days lost to injury thereby increasing player availability. In 2010/11, the team won both its highest number of points and conceded its lowest number of goals especially over the second half of this season. The team also won its highest number of games directly via a goal from a substitute and scored and conceded a goal first on the highest and lowest number of occasions, respectively. While multivariate analysis of variance (MANOVA) detected a significant difference in some attacking and defensive performance indicators across the five seasons, these were generally not distinguishing factors in 2010/11. Similarly, univariate ANOVAs showed a significant difference in running distances covered across seasons, but the trend was for less activity in 2010/11

The topological structure of scaling limits of large planar maps

We discuss scaling limits of large bipartite planar maps. If p is a fixed integer strictly greater than 1, we consider a random planar map M(n) which is uniformly distributed over the set of all 2p-angulations with n faces. Then, at least along a suitable subsequence, the metric space M(n) equipped with the graph distance rescaled by the factor n to the power -1/4 converges in distribution as n tends to infinity towards a limiting random compact metric space, in the sense of the Gromov-Hausdorff distance. We prove that the topology of the limiting space is uniquely determined independently of p, and that this space can be obtained as the quotient of the Continuum Random Tree for an equivalence relation which is defined from Brownian labels attached to the vertices. We also verify that the Hausdorff dimension of the limit is almost surely equal to 4.Comment: 45 pages Second version with minor modification

Clinique de l'équilibration Occlusale

Occlusion fonctionnelle Tome

Confluence of geodesic paths and separating loops in large planar quadrangulations

We consider planar quadrangulations with three marked vertices and discuss the geometry of triangles made of three geodesic paths joining them. We also study the geometry of minimal separating loops, i.e. paths of minimal length among all closed paths passing by one of the three vertices and separating the two others in the quadrangulation. We concentrate on the universal scaling limit of large quadrangulations, also known as the Brownian map, where pairs of geodesic paths or minimal separating loops have common parts of non-zero macroscopic length. This is the phenomenon of confluence, which distinguishes the geometry of random quadrangulations from that of smooth surfaces. We characterize the universal probability distribution for the lengths of these common parts.Comment: 48 pages, 33 color figures. Final version, with one concluding paragraph and one reference added, and several other small correction

Packing and Hausdorff measures of stable trees

In this paper we discuss Hausdorff and packing measures of random continuous trees called stable trees. Stable trees form a specific class of L\'evy trees (introduced by Le Gall and Le Jan in 1998) that contains Aldous's continuum random tree (1991) which corresponds to the Brownian case. We provide results for the whole stable trees and for their level sets that are the sets of points situated at a given distance from the root. We first show that there is no exact packing measure for levels sets. We also prove that non-Brownian stable trees and their level sets have no exact Hausdorff measure with regularly varying gauge function, which continues previous results from a joint work with J-F Le Gall (2006).Comment: 40 page

Lithospheric mantle evolution monitored by overlapping large igneous provinces: case study in southern Africa

Most of the studies on the large igneous provinces (LIPs) focus on Phanerozoic times, and in particular, thoserelated to the disruption of Pangea (e.g. CAMP, Karoo, Parana–Etendeka) while Precambrian LIPs (e.g.Ventersdorpf, Fortescue) remain less studied. Although the investigation of Precambrian LIPs is difficultbecause they are relatively poorly preserved, assessment of their geochemical characteristics in parallel withyounger overlapping LIP is fundamental for monitoring the evolution of the mantle composition through time.Recent 40Ar/39Ar dating of the Okavango giant dyke swarm (and related sills) in southern Africa showed that~90% of the dykes were emplaced at 179±1Ma and belong to the Karoo large igneous province whereas ~10% ofdykes yielded Proterozoic ages (~1–1.1 Ga). Here,weprovide newmajor, trace and rare earth elements analysesof the low-Ti Proterozoic Okavango dyke swarm (PODS) that suggest, combined with age data, a cognate originwith the 1.1 Ga Umkondo large igneous province (UIP), southern Africa.The geochemical characteristics of the PODS and UIP basalts are comparable to those of overlapping low-TiKaroo basalts, and suggest that both LIPs were derived from similar enriched mantle sources. A mantle plumeorigin for these LIPs is not easily reconciled with the geochemical dataset and the coincidence of twocompositionally similar mantle plumes acting 900 Myr apart is unlikely. Instead,we propose that the Umkondoand Karoo large igneous provinces monitored the slight evolution of a shallow enriched lithospheric mantlefrom Proterozoic to Jurassic