Positional Differences in Peak- and Accumulated- Training Load Relative to Match Load in Elite Football

Quantification of training and match load is an important method to personalize the training stimulus' prescription to players according to their match demands. The present study used time-motion analysis and triaxial-accelerometer to quantify and compare: a) The most demanding passages of play in training sessions and matches (5-min peaks); b) and the accumulated load of typical microcycles and official matches, by playing position. Players performance data in 15 official home matches and 11 in-season microcycles were collected for analysis. Players were divided into four different playing positions: Centre-backs, wing-backs, centre midfielders, and centre forwards. The results show that match demands were overperformed for acceleration counts (acc_counts) (131%-166%) and deceleration counts (dec_counts) (108%-134%), by all positions. However, relative to match values, training values for sprint distance (sprint_dist) and high-intensity run distance (HIR_dist) were considerably lower (36%-61% and 57%-71%) than for accelerations and decelerations. The most pronounced difference on the 5-min peaks was observed in sprints (sprint_peak), with wing-backs achieving during the microcycle only 64% of the sprint_peak in matches, while centre backs, centre midfielders, and centre forwards levelled and overperformed the match values (107%, 100%, and 107%, respectively). Differences observed across playing positions in matches and microcycles underline the lack of position specificity of common training drills/sessions adopted by coaches in elite football.

Virtual sports deserve real sports medical attention

In recent years, virtual sports or ‘eSports’ have grown exponentially both recreationally and at the professional level. eSports comprise several regulated video games played competitively, using electronic platforms. Some eSports competitions present a structure comparable to traditional sports, and eSports players, even with major skills and mental focus, need preparation and training to thrive. However, little is known about the demands of eSports competitions and continuous training. As the popularity and stakes rise, concerns about the health and emerging risks of eSports participation might arise. Indeed, in the absence of proper descriptive data about the specific characteristics of the eSports population (including factors such as screen time, physical activity, overuse injuries or training environment), effective prevention and care cannot be developed nor provided. Therefore, quality healthcare and prevention strategies are needed. In the current viewpoint, we argue that those involved with Sports Science and Medicine should lead the discussion and reflect on the health effects of eSports participation, providing scientifically-based arguments to better answer to the current eSports professionalism.

The 400-m Front Crawl Test: Energetic and 3D Kinematical Analyses

The aim of the study was to verify the relative contributions of energetic and kinematic parameters to the performance in 400-m front crawl test. Fourteen middle-distance swimmers participated in the study. Oxygen consumption was measured directly and blood samples were collected to assay lactate concentration. Both oxygen consumption and lactate concentration were used to calculate the: (i) overall energy expenditure, (ii) anaerobic (alactic and lactic) and (iii) aerobic contributions. The mean centre of mass speed and intracycle velocity variation were determined through three-dimensional kinematic analysis. Mean completion time was 315.64±26.91s. Energetic contributions were as follows: 6.1±0.28% from alactic anaerobic metabolism, 5.9±0.63% from anaerobic lactic and 87.8±0.88% from aerobic. Mean intracycle velocity variation was 0.14±0.03. The results indicated that performance of 400-m test relies predominantly on aerobic power. Parameters such as lactate, mean speed, anaerobic lactic and alactic (kW) correlated with performance of 400-m test (p <0.05). Multiple linear regressions indicated that mean centre of mass speed and anaerobic alactic (kW) determined the 400-m test performance (R²=0.92). Even though the T400 is characterized by aerobic metabolism, the anaerobic alactic component cannot be negligible at this competition level.

Methods to collect and interpret external training load using microtechnology incorporating GPS in professional football: a systematic review

The aim of this article was to systematically review the methods adopted to collect and interpret external training load (ETL) using microtechnology incorporating global positioning system (GPS). The main deficiencies identified concerned the non-collection of match ETL, and the non-consideration of potential confounders (e.g. playing position, fitness level, starting status or session content). Also, complementary training (individual/reconditioning) and pre-match warm-up were rarely quantified. To provide a full picture of the training demands, ETL was commonly complemented by internal training load monitoring with the rating of perceived exertion predominantly adopted instead of heart rate recordings. Continuous data collection and interpretation of ETL data in professional football vary widely between observational studies, possibly reflecting the actual procedures adopted in practical settings. Evidence about continuous ETL monitoring in female players, and female as well as male goalkeepers is lacking.

Can Heart Rate Variability Determine Recovery Following Distinct Strength Loadings? A Randomized Cross-Over Trial

This study aimed to compare the acute effects of hypertrophic (HYP) and maximum strength (MAX) loadings on heart rate variability (HRV) and to compare possible loading-specific alterations with other markers of recovery. Ten young men with strength training experience performed two leg press loadings (HYP: five times 10 repetitions at 70% of one repetition maximum (1RM) with 2 minutes inter-set rest; MAX: 15 times one repetition at 100% of 1RM with 3 minutes inter-set rest) in a randomized order. The root mean square of successive differences statistically decreased after both protocols (HYP: 65.7 ± 26.6 ms to 23.9 ± 18.7 ms, p = 0.026; MAX: 77.7 ± 37.0 ms to 55.3 ± 22.3 ms, p = 0.049), while the frequency domains of HRV remained statistically unaltered. The low frequency (LF) band statistically increased at 48h post-MAX only (p = 0.033). Maximal isometric voluntary contraction (MVC) statistically decreased after HYP (p = 0.026) and returned to baseline after 24h of recovery. Creatine kinase (CK) statistically increased above baseline at 1h post-loadings (HYP p = 0.028; MAX p = 0.020), returning to baseline at 24h post. Our findings indicate no distinct associations between changes in HRV and MVC or CK.

Internal training load monitoring in professional football: a systematic review of methods using rating of perceived exertion

INTRODUCTION

The rate of perceived exertion (RPE) is widely adopted to quantify internal training load (ITL) in professional football. The aim of this study was to systematically review the use RPE-based methods in professional football.

EVIDENCE ACQUISITION

Observational studies conducted during training routines of professional football players over a minimum of one-week were selected based on the preferred reporting items for systematic reviews and meta-analyses statement.

EVIDENCE SYNTHESIS

Thirty-eight articles met the inclusion criteria (average qualitative score was 6.3 out of 10 [3 to 9]). The main deficiencies identified concerned the poor description of study design (~52% of the studies), and the non-quantification of match load (~44%). Ten studies complemented RPE-based ITL information with time-motion analysis (~26%) and seven studies added HR recordings (~18%). Nine studies collected RPE data after complementary training, separately to field sessions (~3%). Operational questions (e.g. How was your workout? ~71%) were preferred to instructions (e.g. Please rate the intensity of today's session; ~8%). Session-RPE (s-RPE; RPE multiplied by training duration) was more commonly adopted as measure of exercise intensity than isolated RPE (~76 vs. ~8%). RPE-derived variables calculated on weekly values included absolute week-to-week change, acute: chronic workload ratio, monotony and strain and were not frequently used (7 to 15%). Four studies (~11%) divided RPE in two components: respiratory and muscular.

CONCLUSIONS

There is a lack of consensus for the use of RPE in professional football and "good practices" are warranted. This review might help practitioners regarding procedures to adopt in RPE data collection and interpretation.

Enzymatic Polymerization of PCL-PEG Co-polymers for Biomedical Applications

Biodegradable polymers, obtained via chemical synthesis, are currently employed in a wide range of biomedical applications. However, enzymatic polymerization is an attractive alternative because it is more sustainable and safer. Many lipases can be employed in ring-opening polymerization (ROP) of biodegradable polymers. Nevertheless, the harsh conditions required in industrial context are not always compatible with their enzymatic activity. In this work, we have studied a thermophilic carboxylesterase and the commonly used Lipase B from Candida antarctica (CaLB) for tailored synthesis of amphiphilic polyesters for biomedical applications. We have conducted Molecular Dynamics (MD) and Quantum Mechanics/Molecular Mechanics (QM/MM) MD simulations of the synthesis of Polycaprolactone-Polyethylene Glycol (PCL-PEG) model co-polymers. Our insights about the reaction mechanisms are important for the design of customized enzymes capable to synthesize different polyesters for biomedical applications.

Using the Rating of Perceived Exertion and Heart Rate to Quantify Training Intensity in Female Soccer Players: Validity and Utility

Costa, JA, Brito, J, Nakamura, FY, Figueiredo, P, and Rebelo, A. Using the rating of perceived exertion and heart rate to quantify training intensity in female soccer players: validity and utility. J Strength Cond Res XX(X): 000-000, 2019-The aims of this study were as follows: (a) to analyze associations between session rating of perceived exertion (sRPE) and training impulse (TRIMP); (b) to verify whether significantly different ranges of percentage of heart rate peak (%HRpeak) would be reached in each discrete RPE category; and (c) to investigate the amount of time spent >90% of HRpeak and associated intraplayer and interplayer variability during soccer technical training sessions with similar contents and duration. This was a single-group observational study that measured the internal training load during 6 weeks of the competitive period in 17 high-level female soccer players. All training sessions started around 9 PM. and lasted on average 94 ± 5 minutes. During each training session, RPE, sRPE, TRIMP, HRex (%HRpeak), and time spent at >90% of HRpeak were assessed. A very large correlation was found between sRPE and TRIMP (r = 0.78; 95% confidence interval: [0.74-0.82]). Significant differences were observed between %HRpeak associated with each RPE value (i.e., RPE = 2 arbitrary unit [68%; 65-69% of %HRpeak]; RPE 3 [72%; 69-75%]; RPE 4 [79%; 76-82%]; RPE 5 [84; 81-87%]; χ = 73.34; df = 3; P < 0.001). Intraplayer and interplayer coefficients of variation for the time spent >90% of HRpeak (∼8% of training time, ∼7 minutes per session) during training sessions were 73 and 92%, respectively. In conclusion, it was confirmed that sRPE and TRIMP displayed good convergent validity, and different %HRpeak were observed for each discrete RPE. However, because of the high variability in the time >90% of HRpeak, careful monitoring of individual exercises should be performed to ensure the desired training stimulus for each player.

Task Constraints and Coordination Flexibility in Young Swimmers

This study aimed to examine young swimmers' behavioral flexibility when facing different task constraints, such as swimming speed and stroke frequency. Eighteen (five boys and 13 girls) 13- to 15-year-old swimmers performed a 15 × 50-m front crawl with five trials, at 100%, 90%, and 70% each of their 50 m maximal swimming speed and randomly at 90%, 95%, 100%, 105%, and 110% of their preferred stroke frequency. Seven aerial and six underwater cameras were used to assess kinematics (one cycle), with upper-limb coordination computed through a continuous relative phase and index of coordination. A cluster analysis identified six patterns of coordination used by swimmers when facing various speed and stroke frequency constraints. The patterns' nature and the way the swimmers shifted between them are more important than getting the highest number of patterns (range of repertoire), that is, a change in the motor pattern in order to adapt correctly is more important than being able to execute a great number of patterns.

Associations of Quadriceps Torque Properties with Muscle Size, Attenuation, and Intramuscular Adipose Tissue in Older Adults

Background

Atrophy and fatty infiltration of muscle with aging are associated with fractures and falls, however, their direct associations with muscle function are not well described. It was hypothesized that participants with lower quadriceps muscle attenuation, area, and greater intramuscular adipose tissue (IMAT) will exhibit slower rates of torque development (RTD) and lower peak knee extension torques.

Methods

Data from 4,842 participants (2,041 men, 2,801 women) from the Age Gene/Environment Susceptibility Reykjavik Study (mean age 76 ± 0.1 years) with complete thigh computed tomography and isometric knee testing. Regression models were adjusted for health, behavior, and comorbidities. Muscle attenuation was further adjusted for muscle area and IMAT; muscle area adjusted for IMAT and attenuation; and IMAT adjusted for muscle area and attenuation. Standardized betas (β) indicate association effect sizes.

Results

In the fully-adjusted models, attenuation (men β = 0.06, 95% CI: 0.01, 0.11; women β = 0.07, 95% CI: 0.03, 0.11) and muscle area (men β = 0.13, 95% CI: 0.07, 0.19; women β = 0.10, 95% CI: 0.06, 0.15) were associated with knee RTD. Attenuation (men β = 0.12, 95% CI: 0.08, 0.16; women β = 0.12, 95% CI: 0.09, 0.16) and muscle area (men β = 0.38, 95% CI: 0.33, 0.43; women β = 0.33, 95% CI: 0.29, 0.37) were associated with peak torque.

Conclusions

These data suggest that muscle attenuation and area are independently associated with RTD and peak torque; and that area and attenuation demonstrate similar contributions to RTD.

A comparison of match-physical demands between different tactical systems: 1-4-5-1 vs 1-3-5-2

The team tactical system and distribution of the football players on the pitch is considered fundamental in team performance. The present study used time-motion analysis and triaxial-accelerometers to obtain new insights about the impact of different tactical systems (1-4-5-1 and 1-3-5-2) on physical performance, across different playing positions, in a professional football team. Player performance data in fifteen official home matches was collected for analysis. The sample included twenty-two players from five playing positions (centre backs: n = 4; full-back/wide midfielder/ wing-back: n = 9; centre midfielder: n = 6 and centre forward: n = 3), making a total of 108 match observations. A novel finding was that general match physical demands do not differ considerably between these tactical formations, probably because match-to-match variability (variation of players’ running profile from match-to-match) might be higher than the differences in physical performance between tactical systems. However, change of formation had a different impact across playing positions, with centre backs playing in 1-4-5-1 performing significant more HIRcounts than in 1-3-5-2 (p = 0.031). Furthermore, a medium effect size (r = 0.33) was observed in HIRdist, with wide players covering higher distances when playing in 1-3-5-2 than in 1-4-5-1. These findings may help coaches to develop individualised training programs to meet the demands of each playing position according to the tactical system adopted.

Comparison of different histological indexes in the assessment of UC activity and their accuracy regarding endoscopic outcomes and faecal calprotectin levels

OBJECTIVE

Histological remission is being increasingly acknowledged as a therapeutic endpoint in patients with UC. The work hereafter described aimed to evaluate the concordance between three histological classification systems-Geboes Score (GS), Nancy Index (NI) and RobartsHistopathologyIndex (RHI), as well as to evaluate their association with the endoscopic outcomes and the faecal calprotectin (FC) levels.

DESIGN

Biopsy samples from 377 patients with UC were blindly evaluated using GS, NI and RHI. The results were compared with the patients' Mayo Endoscopic Score and FC levels.

RESULT

GS, NI and RHI have a good concordance concerning the distinction between patients in histological remission or activity. RHI was particularly close to NI, with 100% of all patients classified as being in remission with NI being identified as such with RHI and 100% of all patients classified as having activity with RHI being identified as such with NI. These scores could also predict the Mayo Endoscopic Score and the FC levels, with their sensitivity and specificity levels depending on the chosen cut-offs. Moreover, higher FC levels were statistically associated with the presence of neutrophils in the epithelium, as well as with ulceration or erosion of the intestinal mucosa.

CONCLUSIONS

GS, NI and RHI histopathological scoring systems are comparable in what concerns patients' stratification into histological remission/activity. Additionally, FC levels are increased when neutrophils are present in the epithelium and the intestinal mucosa has erosions or ulcers. The presence of neutrophils in the epithelium is, indeed, the main marker of histological activity.

Relationship between External Load and Perceptual Responses to Training in Professional Football: Effects of Quantification Method

We examined the within-player correlation between external training load (ETL) and perceptual responses to training in a professional male football team (n = 13 outfield players) over an eight-week competitive period. ETL was collected using 10-Hz GPS, whereas perceptual responses were accessed through rating of perceived exertion (RPE) questionnaires. Moderate-speed running (MSR), high-speed running (HSR) and sprinting were defined using arbitrary (fixed) and individualised speed zones (based on maximal aerobic speed and maximal sprinting speed). When ETL was expressed as actual distance covered within the training session, perceptual responses were moderately correlated to MSR and HSR quantified using the arbitrary method (p < 0.05; r = 0.53 to 0.59). However, the magnitude of correlations tended to increase when the individualised method was used (p < 0.05; r = 0.58 to 0.67). Distance covered by sprinting was moderately correlated to perceptual responses only when the individualised method was used (p < 0.05; 0.55 [0.05; 0.83] and 0.53 [0.02; 0.82]). Perceptual responses were largely correlated to the sum of distance covered within all three speed running zones, irrespective of the quantification method (p < 0.05; r = 0.58 to 0.68). When ETL was expressed as percentage of total distance covered within the training session, no significant correlations were observed (p > 0.05). Perceptual responses to training load seem to be better associated with ETL, when the latter is adjusted to individual fitness capacities. Moreover, reporting ETL as actual values of distance covered within the training session instead of percentual values inform better about players’ perceptual responses to training load.

Abstract P3-13-05: Comparing conventional breast conserving surgery with the minimally invasive approach technique to treat early breast cancer - a retrospective case control study

Background/Objective: The objective of the study was to compare the oncological safety and aesthetical results between the minimally invasive technique and the conventional breast conserving surgery. Breast conserving surgery was developed to avoid mastectomy and has become the standard of care in early stage breast cancer. Patient concerns with aesthetics have led to the development of oncoplastic surgical approaches. It has been demonstrated that the aesthetic success in breast cancer surgical treatment leads to improved sexual and social recovery. In patients that have no desire or no need for associated mammoplasty, minimally invasive treatments allow the maintenance of the breast pre-surgical appearance. The mínimally invasive technique is an oncoplastic surgery aimed to remove both the breast tumor and the sentinel lymph node through one incision, thus providing better aesthetic results than the conventional breast conservative two incision technique.

Methods: We retrospectively evaluated 2 cohorts of 60 consecutive early breast cancer patients ( invasive breast cancer measuring no more than 25mm and clinically axillary negative lymph nodes ) operated by either conventional breast conserving surgery (N=26) or one incision surgery (N=34). We selected patients that have no desire or no need for associated mammoplasty. We compared the mammary volume tissue removed; surgical time; number of dissected lymph nodes; surgical complications such as seroma, infection, and dehiscence of the surgical wound; and deformities, retractions, and subsequent aesthetic sequelae.

Results: In the minimally invasive technique group the breast volume removed was significantly lower than in the conventional surgery technique group as well as was the surgical time and the number of dissected lymph nodes.

Demographics and surgical results Minimally invasive surgery ( n=34)Conventional surgery (n=26)P valueAge  0.241Medium53.9(11.4)57.4(11.3) Range33 - 7634 - 85 Disease Stage  0.482I30(88.2)21(80.8) II4(11.8)5(19.2) Incision  &gt;0.99Axilla1 (3.1)0 (0.0) Periareolar21(65.6)17(65.4) Sulcus10(31.3)9(34.6) Breast dissected volume  &lt;0.001Medium16.3(8.5; 26.7)42.4(14.4; 112.2) Range2 - 905 - 270 Dissected lymph nodes  &lt;0.001Medium (IIQ)2(1-5)4(1-13) Range1 - 181 - 31 Surgical time (min)  0.010Medium130(105; 170)180(110; 240) Range30 - 22050 - 275 

No cases required enlargement of the margins and aesthetical results were better in theminimally invasive technique with only incision group.

Conclusions: The minimally invasive approach to treat early breast cancer was shown to be similar to the conventional breast conserving surgery in terms of oncologic outcomes but providing better cosmetic result.

Citation Format: Bromberg S, Figueiredo P, Ades F. Comparing conventional breast conserving surgery with the minimally invasive approach technique to treat early breast cancer - a retrospective case control study [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-13-05.

The Role of the CLIF-C OF and the 2016 MELD in Prognosis of Cirrhosis with and without Acute-on-Chronic Liver Failure

INTRODUCTION AND AIM

Acute-on-chronic liver failure (ACLF) is defined by the development of acute deterioration of liver function associated with failure of other organs and high short-term mortality in patients with chronic liver disease (CLD). There is no consensus on the diagnostic criteria, and its independence from ordinary decompensation of CLD has frequently been questioned. This study aimed to identify and characterize this condition and to test the CLIF-C OF score comparing it to the 2016-MELD (with sodium) and the Child-Pugh.

MATERIAL AND METHODS

18-month prospective observational study with systematic inclusion of admitted patients with CLD decompensation.

RESULTS

39 patients had ACLF (33.1%). These patients experienced higher 28-day and 90-day mortality, when compared to patients without ACLF (43.6% and 64.1% vs. 2.5% and 7.6% respectively, p < 0.0001). ACLF was linked with a higher acute infection rate (74.4%). For all patients (N = 118), the scores 2016-MELD, CLIF-C OF and Child-Pugh showed an area under the curve (AUC) for 28-day mortality of 0.908, 0.844, 0.753 and for 90-day of 0.902, 0.814, 0.724 respectively, p < 0.0001 for all scores. The 90-day mortality 2016-MELD AUC was greater than the CLIF-C OF AUC, p = 0.021. Within ACLF patients, the 2016-MELD, CLIF-C ACLF and Child-Pugh scores showed an AUC of 0.774, 0.734, 0.584 (28-day) and 0.880, 0.771, 0.603 (90-day); for 2016-MELD p = 0.004 (28-day) and p < 0.0001 (90-day).

CONCLUSION

ACLF is a frequent and relevant condition, associated with high mortality. The CLIF-C OF score revealed good accuracy and diagnoses ACLF when it is present. However, the 2016-MELD performed better for 90-day mortality prediction.

Processos de amostragem e cálculo para determinação do tamanho da amostra: critérios e métodos adotados em teses e dissertações em Ciências do Movimento Humano - um estudo descritivo

Trabalhos monográficos quantitativos utilizam, sistematicamente, procedimentos estatísticos inferenciais para testar hipóteses. Para tanto, é necessário que os procedimentos de amostragem e os tamanhos amostrais estejam adequados aos procedimentos propostos. Objetivou-se identificar os métodos de seleção amostral, bem como a realização e os tipos de cálculo para determinação do tamanho amostral adotados em teses e dissertações desenvolvidas em um programa de pós-graduação no campo da Educação Física. As teses e dissertações, defendidas entre 2003 e 2013, foram obtidas via repositório digital. Foram incluídos apenas estudos de caráter quantitativo, nos quais analisou-se: (1) critério para seleção amostral; (2) presença de cálculo amostral; (3) tipo de cálculo para estimativa do tamanho amostral. Foram incluídos 199 trabalhos. Dentre estes, 6% (n=11) usaram métodos probabilísticos para seleção amostral e 3% (n=6) usaram amostra animal. Quanto à realização de cálculo amostral 36% (n=72) dos trabalhos relatam ter adotado. Dos estudos que citam ter realizado cálculos, 25% (n=18) usaram equações preditivas, 67% (n=48) consideraram métodos com o poder estatístico como base, 3% (n=2) usaram o intervalo de confiança, 4% (n=3) não citam o método e 1% (n=1) baseou-se no tipo de teste estatístico a ser usado posteriormente. Os métodos de amostragem não-probabilísticos predominam para a seleção dos sujeitos; grande parte dos estudos não relata adotar cálculos para a estimativa do tamanho amostral e dentre aqueles que citam utilizar, os modelos que consideram o poder estatístico como principal critério são predominantes.

Top 50 most-cited articles in medicine and science in football

Objectives

To conduct a comprehensive mapping analysis to the scientific literature published in football aiming to identify the areas of bigger interest and potential for further exploration.

Methods

The data were obtained by a search conducted on the Web of Science. Articles were listed based on citation frequency. We used an open-source bibliometrix R-package for the comprehensive bibliometric analyses.

Results

The number of citations per article ranged from 251 to 869 (median 323; IQR 125). The yearly number of citations ranged from 8 to 54 (median 26; IQR 11). Most of the articles (76%) were of level III of evidence, 10% were level II and 14% were level IV. Within the top 50 most-cited articles, 40 articles were original research (37 observational and 3 experimental studies), 9 were review articles and 1 was a thesis. From the 40 original research articles, 50% involved elite players, 73% were exclusive to male players and 80% involved adult players only. The topic area with the highest number of articles was sports medicine (44%), followed by training and testing (32%), performance analysis (14%) and physiology (10%). No study within the top 50 was devoted to biomechanics, nutrition, sport psychology, coaching or social sciences.

Conclusions

The lack of experimental studies within the top 50 most-cited articles in football clearly underpins how far we still are from establishing the theoretical and methodological guidelines for the applied science and medicine in football.

InP-based quantum cascade lasers monolithically integrated onto silicon

Lasing is reported for ridge-waveguide devices processed from a 40-stage InP-based quantum cascade laser structure grown on a 6-inch silicon substrate with a metamorphic buffer. The structure used in the proof-of-concept experiment had a typical design, including an Al_0.78In_0.22As/In_0.73Ga_0.27As strain-balanced composition, with high strain both in quantum wells and barriers relative to InP, and an all-InP waveguide with a total thickness of 8 µm. Devices of size 3 mm x 40 µm, with a high-reflection back facet coating, emitted at 4.35 µm and had a threshold current of approximately 2.2 A at 78 K. Lasing was observed up to 170 K. Compared to earlier demonstrated InP-based quantum cascade lasers monolithically integrated onto GaAs, the same laser structure integrated on silicon had a lower yield and reliability. Surface morphology analysis suggests that both can be significantly improved by reducing strain for the active region layers relative to InP bulk waveguide layers surrounding the laser core.

Rehabilitation of simultaneous bilateral epiphysial fracture of proximal tibia in adolescent

Simultaneous and bilateral epiphysial fracture of the proximal tibia is an extremely rare injury, with only 23 cases reported in the literature. In this paper, we present a 15-year-old adolescent with a simultaneous and bilateral epiphysial fracture of the proximal tibia in sport context (trampoline jump). He underwentsurgical repair with bilateral closed reduction and internal fixation, followed by outpatient rehabilitation programme during 4 months. There was a good functional outcome, without limitation in activities of daily living and with resumption of amateur sports activity. Since there are no guidelines described for this pathology, the authors suggest a rehabilitation protocol for bilateral epiphysial fractures of the proximal tibia that underwent surgical treatment previously and in which there were no complications in the acute phase.