Serum per- and polyfluoroalkyl substance (PFAS) levels and health-related biomarkers in a pilot study of skiers in New England.

BACKGROUND: Per- and polyfluoroalkyl substances (PFAS), synthetic chemicals with adverse health effects, are used extensively in consumer products. Ski waxes, applied to the base of skis, contain up to 100% PFAS by mass, but exposure and health effects are poorly characterized. OBJECTIVES: Our objectives were to quantify serum PFAS concentrations among skiers and explore associations with reported ski wax use and biomarkers of cardiometabolic, thyroid, and immune health. METHODS: We recruited 30 active adult skiers to provide non-fasting blood samples and complete questionnaires. We quantified 18 PFAS using mass spectrometry, and measured serum lipids, thyroid hormones, and immunoglobulins. We explored associations of individual and aggregate measures of serum PFAS with wax use indicators and health biomarkers using multivariable regression models, adjusted for age and gender identity. RESULTS: Nine PFAS (PFBS, PFHpS, PFHxS, Sm-PFOS, n-PFOS, PFDA, PFNA, PFUnDA, n-PFOA) were detected in 100% of participants, and MeFOSAA in 93%. Compared to NHANES, median serum concentrations (ng/ml) were similar, but higher in coaches (e.g., PFOAall: 1.1, PFOAcoaches: 2.7, PFOANHANES: 1.2; PFNAall: 0.5, PFNAcoaches: 1.7, PFNANHANES: 0.4). Factors reflecting wax exposure were positively associated with PFAS: e.g., >10 years as a snow sport athlete, compared to <10 years, was associated with 3.2 (95% CI: 0.7, 5.6) ng/ml higher aggregate PFAS, as defined by National Academies of Science, Engineering, and Medicine (NASEM). An IQR (6.3 ng/ml) increase in NASEM PFAS was associated with 32.1 (95% CI: 7.0, 57.2), 35.5 (13.5, 57.5), and 12.8 (0.6, 25.1) mg/dl higher total cholesterol, LDL-C, and sdLDL-C, respectively. DISCUSSION: Our study provides early evidence that recreational skiers, particularly coaches, are exposed to PFAS through ski wax. Several PFAS were associated with higher serum lipids among these physically active adults. Interventions to remove PFAS from fluorinated wax could decrease direct exposure to skiers and reduce PFAS release into the environment.

The Transverse Sigmoid Notch Morphology Unravelled.

Background: Several studies have described pathology in relation to transverse sigmoid notch morphology, using the Tolat transverse sigmoid notch classification. It is believed that the entire shape of a sigmoid notch can be described using Tolat sigmoid types. We hypothesised that the determination of the sigmoid notch shape (SNS) depends on the level of the transverse CT plane on the axial axis of the distal radius. The aim of this study was to determine and compare the transverse SNS on different axial CT levels in the same wrist. Methods: The transverse SNS of 53 participants were independently qualitatively classified by two researchers in accordance with the four morphologies described by Tolat et al. The SNS was determined at two levels on the axial axis of the distal radius; at the level of the most prominent part of Lister tubercle, determined on the sagittal plane and at the level of the 'smallest distance between the ulnar head and sigmoid notch' (SDUS). Results: Forty-seven percent of the wrists demonstrated different SNS types according to Tolat classification, depending on the axial level of the CT scan. Interobserver agreement on the transverse sigmoid shape was 87% at Lister tubercle and 85% at SDUS, which can both be interpreted as 'excellent'. Conclusions: Despite an excellent interobserver agreement, 47% of the study population had different transverse sigmoid notch types within the same wrist. We, therefore, conclude that Tolat transverse sigmoid classification may not be useful for the description of potential pathology in relation to the sigmoid notch morphology.

Aerobic capacity and respiratory indices of junior cross-country skiers and biathletes during incremental exercise testing.

The present study compared the isocapnic buffering phase (ICB), hypocapnic hyperventilation phase, ventilatory threshold (VT), respiratory compensation point (RCP), and maximum oxygen uptake (VO2max) among biathlon and cross-country ski athletes during an incremental exercise test. 37 male and 33 female Turkish National Team athletes volunteered to participate in the research. Body fat percentage, lean mass, and fat mass values of athletes were measured using the bioelectrical impedance analysis method, and oxygen consumption (VO2) was measured with a portable cardiopulmonary exercise test system with a ramp protocol on the treadmill. In VT, RCP, and VO2max phases, male athletes had higher VO2 and speed values than female athletes (p < 0.05). In contrast, they had similar values across different categories of sports (biathlon and cross-country skiing) (p > 0.05). Additionally, XC skiers and males had higher absolute (Abs) VO2 and mass-normalized (Rel) VO2 values than biathletes and females in exhaustion times and ICBs (p < 0.05). In contrast, they had similar Abs VO2 and Rel VO2 values in hypocapnic hyperventilation phases (p > 0.05). In addition, XC skiers and males had higher absolute (Abs) VO2 and relative (Rel) VO2 values than biathletes and females in exhaustion times and ICBs (p < 0.05). In contrast, they had similar Abs VO2 and Rel VO2 values in hypocapnic hyperventilation phases (p > 0.05). These results indicate significant differences in physiological profiles between male and female athletes and between XC skiers and biathletes.

Consuming Beetroot Juice Improves Slalom Performance and Reduces Muscle Soreness in Alpine Skiers under Hypoxic Conditions.

Background: Beetroot juice (BRJ) supplementation has been shown to increase sports performance under hypoxic conditions and to improve athletes' recovery. Objectives: In the present study, we aimed to investigate the effect of acute BRJ supplementation on slalom (SL) run performance and muscle soreness (MS) in Alpine skiers at moderate to high altitudes. Methods: Ten male Alpine skiers received 220 mL of BRJ (8.9 mmol/L nitrate) or placebo (PLA) in 2 sessions with a 7-d wash out interval in a randomized, crossover, PLA-controlled, double-blind study. The 90-s box jump (BJ90), agility hexagonal obstacle jump (Hex Jump), and wall-sit tests were measured before on-hill SL runs in both sessions. After the functional tests, SL run performance was measured by time to complete 2 runs on the SL course; immediately after each SL run, the rating of perceived exertion (RPE) was recorded. In addition, perceived MS was recorded using the visual analog scale at 12, 24, and 48 h after the SL runs. Results: The data were meticulously analyzed using 2-way repeated measures analysis of variance and paired t tests with significance set at P < 0.05. The findings were significant, indicating that compared with PLA, BRJ notably improved wall-sit and BJ90 performances (P < 0.05), while a substantial reduction was observed in RPE, Hex Jump, and MS (P < 0.05). A 1.74% shorter time to complete SL runs was observed in the BRJ group compared with the PLA group; however, there were no significant differences between the PLA and BRJ groups (P > 0.05). Conclusions: These results underscore the potential of BRJ supplementation to enhance sports performance and reduce MS in Alpine skiers under hypoxic conditions.

The Essential Role of Angiogenesis in Adenosine 2A Receptor Deficiency-mediated Impairment of Wound Healing Involving c-Ski via the ERK/CREB Pathways.

Adenosine receptor-mediated signaling, especially adenosine A2A receptor (A2AR) signaling, has been implicated in wound healing. However, the role of endothelial cells (ECs) in A2AR-mediated wound healing and the mechanism underlying this effect are still unclear. Here, we showed that the expression of A2AR substantially increased after wounding and was especially prominent in granulation tissue. The delaying effects of A2AR knockout (KO) on wound healing are due mainly to the effect of A2AR on endothelial cells, as shown with A2AR-KO and EC-A2AR-KO mice. Moreover, the expression of c-Ski, which is especially prominent in CD31-positive cells in granulation tissue, increased after wounding and was decreased by both EC-A2AR KO and A2AR KO. In human microvascular ECs (HMECs), A2AR activation induced EC proliferation, migration, tubule formation and c-Ski expression, whereas c-Ski depletion by RNAi abolished these effects. Mechanistically, A2AR activation promotes the expression of c-Ski through an ERK/CREB-dependent pathway. Thus, A2AR-mediated angiogenesis plays a critical role in wound healing, and c-Ski is involved mainly in the regulation of angiogenesis by A2AR via the ERK/CREB pathway. These findings identify A2AR as a therapeutic target in wound repair and other angiogenesis-dependent tissue repair processes.

Spatial and temporal assessment of China's skiing climate resources.

This study introduces an improved Ski Climate Index (SCI) designed to assess skiing suitability in China by applying fuzzy logic. Using daily meteorological data from 733 weather stations for the periods 1961-1990 and 1991-2020, the study identifies significant changes in SCI distribution over time. Additionally, a coupled analysis is performed, integrating the SCI results with the distribution and spatial vitality of 389 ski resorts in China. This analysis provides a comprehensive understanding of the interplay between actual ski resources and the ongoing evolution of the skiing industry in China and three significant results:1) The snow module has a major impact on SCI distribution, while other non-snow natural elements, such as sunshine duration, wind speed, and thermal comfort, influence the overall SCI assessment less; 2) High SCI values are concentrated in Northwestern and Northeastern China, with increased ski climate resources being observed in Shaanxi-Gansu-Ningxia, Southwest Tibet, and Sichuan due to climate change and noticeable declines in the Southern regions of Northeast China.; 3) In terms of the distribution and vitality of ski resorts, the SCI also partially reflects the development of ski resorts. This skiing suitability model uses climate resources to offer valuable insights for key decision-making in resort development and operation, thereby supporting advancement of the ice-snow economy.

A Smart Ski Pole for Skiing Pattern Recognition and Quantification Application.

In cross-country skiing, ski poles play a crucial role in technique, propulsion, and overall performance. The kinematic parameters of ski poles can provide valuable information about the skier's technique, which is of great significance for coaches and athletes seeking to improve their skiing performance. In this work, a new smart ski pole is proposed, which combines the uniaxial load cell and the inertial measurement unit (IMU), aiming to provide comprehensive data measurement functions more easily and to play an auxiliary role in training. The ski pole can collect data directly related to skiing technical actions, such as the skier's pole force, pole angle, inertia data, etc., and the system's design, based on wireless transmission, makes the system more convenient to provide comprehensive data acquisition functions, in order to achieve a more simple and efficient use experience. In this experiment, the characteristic data obtained from the ski poles during the Double Poling of three skiers were extracted and the sample t-test was conducted. The results showed that the three skiers had significant differences in pole force, pole angle, and pole time. Spearman correlation analysis was used to analyze the sports data of the people with good performance, and the results showed that the pole force and speed (r = 0.71) and pole support angle (r = 0.76) were significantly correlated. In addition, this study adopted the commonly used inertial sensor data for action recognition, combined with the load cell data as the input of the ski technical action recognition algorithm, and the recognition accuracy of five kinds of cross-country skiing technical actions (Diagonal Stride (DS), Double Poling (DP), Kick Double Poling (KDP), Two-stroke Glide (G2) and Five-stroke Glide (G5)) reached 99.5%, and the accuracy was significantly improved compared with similar recognition systems. Therefore, the equipment is expected to be a valuable training tool for coaches and athletes, helping them to better understand and improve their ski maneuver technique.

Negative legacy effects of past forest use on native plant diversity in semi-natural grasslands on ski slopes.

Over the past century, grassland and forest ecosystems globally have been heavily influenced by land-use changes driven by diverse socioeconomic activities. Ski resorts are a modern land-use type associated with biodiversity loss in mountain ecosystems worldwide. Below the treeline, by contrast, some ski slopes have been shown to provide suboptimal semi-natural habitats for native grassland plants and animals, depending on specific construction and management practices. We compared environmental factors and grassland vegetation between two types of ski slopes in central Japan with different land-use histories: slopes constructed on old pastures (pasture slopes) and slopes constructed by clearing secondary forests or larch plantations established on abandoned pastures during the 1940s-1990s (forest slopes). We examined the effects of land-use history and machine grading as well as other environmental factors on ski slope vegetation, including total species richness and the richness of native, endangered, and exotic plants, using a total of 108 plots of 2 m × 10 m. Compared to pasture slopes, forest slopes exhibited significantly lower richness of native grassland species, including endangered species. Forest slopes were more graded than pasture slopes, resulting in lower native and higher exotic grassland species richness. A significantly lower duration of direct sunlight on forest slopes than on pasture slopes likely decreased endangered species richness. The lower species richness on forest slopes may be also caused by seed dispersal limitations. Our findings demonstrate that ski slopes have good potential to support numerous native grassland plant species, including endangered species, but this potential is significantly and negatively affected by forest use history and concomitant environmental changes. The conservation of semi-natural conditions on pasture slopes as habitats for native grassland species can be promoted through the maintenance of annual mowing practices, avoidance of machine grading, and wider ski courses.

Analgesic Effect of SKI306X on Chronic Postischemic Pain and Spinal Nerve Ligation-Induced Neuropathic Pain in Mice.

Neuropathic pain (NP) results from lesions or diseases affecting the peripheral or central somatosensory system. However, there are currently no drugs that are particularly effective in treating this condition. SKI306X is a blend of purified extracts of three oriental herbs (Clematis mandshurica, Trichosanthes kirilowii, and Prunella vulgaris) commonly used to treat osteoarthritis for their chondroprotective effects. Chronic postischemic pain (CPIP) and spinal nerve ligation (SNL) models were created by binding the upper left ankle of mice with an O-ring for 3 h and ligating the L5 spinal nerve, respectively. Mice with allodynia were injected intraperitoneally with 0.9% normal saline (NS group) or different doses (25, 50, or 100 mg/kg) of SKI306X (SKI groups). We assessed allodynia using von Frey filaments before injection and 30, 60, 90, 120, 180, and 240 min and 24 h after injection to confirm the antiallodynic effect of SKI306X. We also measured glial fibrillary acidic protein (GFAP) levels in the spinal cord and dorsal root ganglia to confirm the change of SKI306X administration. Both models exhibited significant mechanical allodynia. The intraperitoneal injection of SKI306X significantly increased the paw withdrawal threshold in a dose-dependent manner, as the paw withdrawal threshold was significantly increased after SKI306X administration compared with at baseline or after NS administration. GFAP levels in the SKI group decreased significantly (p < 0.05). Intraperitoneal administration of SKI306X dose-dependently attenuated mechanical allodynia and decreased GFAP levels, suggesting that GFAP is involved in the antiallodynic effect of SKI306X in mice with CPIP and SNL-induced NP.

WDR61 ablation triggers R-loop accumulation and suppresses breast cancer progression.

Although, superkiller complex protein 8 (SKI8), previously known as WDR61 has been identified and mapped in breast tumor, little is currently known about its function. This study aims to elucidate the role of WDR61 in breast tumor development and its potential as a therapeutic target. Here, we show that tamoxifen-induced knockout of Wdr61 reduces the risk of breast tumors, resulting in smaller tumor size and weight, and improved overall survival. Furthermore, we show that knockdown of WDR61 compromises the proliferation of breast tumor cells with reduced colony-forming capacity. Further investigations demonstrate that the protective effect of WDR61 loss on breast tumor development is due to genomic instability. Mechanistic studies reveal that WDR61 interacts with the R-loop, and loss of WDR61 leads to R-loops accumulation in breast tumor cells, causing DNA damage and subsequent inhibition of cell proliferation. In summary, this study highlights the critical dependence of breast tumors on WDR61, which suppresses R-loop and counteracts endogenous DNA damage in tumor cells.

Fatal injury of a skier during school training - case report.

The authors present the case of a fatal accident of a 16-year-old skier who crashed into a tree during a downhill skiing lesson at school. Although the skier was wearing a protective helmet at the time of the accident and his condition did not appear to be too serious immediately after the accident, he later died in hospital as a result of a craniocerebral injury with cerebral contusion and intracranial haemorrhage. His life could not be saved even by immediate neurosurgery, during which fragments of the broken protective helmet were removed from his cranial cavity. By analysing the international literature, the authors identify head and brain injuries as the most common immediate cause of death in downhill skiing and provide insights into the possibilities of preventing these injuries by simple technical means on the part of ski area operators. These means are in particular protective covers for lift columns and protective nets placed in front of fixed, non-movable obstacles on the track.

Performance and jump-to-jump development in the first female ski flying competition in history.

In 2023, for the first time in history, the international ski and snowboard federation (FIS) arranged an official ski flying competition where the 15 highest ranked women were allowed to participate. This study investigated jump-to-jump performance development in female ski flying, with men's results used as reference data. Official FIS data from all six jumps of women were evaluated together with the eight jumps by men. Performance was evaluated by a score, where the distance points compensated by wind were divided by take-off speed, enabling performance to be evaluated across jumps and sexes. Women improved performance by 96% from the first to the sixth jump, with two major leaps; from the first to the second jump and from the first to the second day. In contrast, men mainly improved from training to competition. The best women had performance scores equivalent to the 10-20 best ranked men and the sex-difference between the top 3 athletes was 26.2%. This difference was thereafter compared to similar results in the normal and large hill World championship in Planica 2023, in which sex-differences between the top 3 were 8.6% and 14.6% in normal and large hill. This historical competition showed the importance of gaining practical experience with ski flying on performance, exemplified by the large improvement of female athletes. This, together with the enlarge sex-differences in large compared to normal hills, indicates that female ski jumpers have a particularly large improvement-potential in ski flying and must gain specific experience on this through traning and competitions.

Investigation of the effects of an 8-week cross-country skiing exercise program on various reaction time parameters, selective attention and academic achievement in adolescents.

Exercise slows or helps reverse the shrinkage of key cognitive brain regions such as the hippocampus, which is important for information processing, learning, reasoning and planning. For this reason, it is thought that regular exercise of individuals, especially during adolescence, which is considered one of the most important processes of development, can increase their performance in areas where cognitive activities are at the forefront. Cross-country skiing, one of the leading branches of winter sports, has a much more complex structure, unlike the branches that are widely preferred today (football, basketball, volleyball, etc.) and is a branch where many motor skills are exhibited at the same time For this reason, the effect of cross-country skiing, which is defined as more complex and difficult in terms of biomotor than other branches, on cognitive activities is a matter of curiosity. Therefore, the aim of the research is; to examine the cognitive effects of cross-country skiing exercise. The study involved 54 (26 male, 28 female) adolescents who had no prior experience in any licensed sports. The average age of the participants was determined as 12.61 ± 1.32. The participants were divided in experimental and control groups. Reaction performances were determined using the ÇAGIN Hand and Foot Reaction Tests, selective attention performances were evaluated using the Flanker Test and academic achievement was determined using the e-Okul system. Two-way ANOVA revealed significant group × time interactions for hand and foot simple, selective, discriminative reaction time, selective attention and academic achievement (p < 0.05) due to improved values at post-test for the experimental group but not for the control groups. No significant group × time interactions were observed for correct reaction rate for all reaction parameters (p > 0.05). The study concludes that the cross-country skiing exercise, which was applied to adolescents for eight weeks, had a positive impact on the parameters of reaction, selective attention and academic achievement. Therefore, parents are suggested to encourage their children to exercise and engage in sports practices like cross-country skiing to improve cognitive and academic performance during adolescence.

Combination of high anti-SKI and low anti-TMED5 antibody levels is preferable prognostic factor in esophageal carcinoma.

Given that esophageal cancer is highly malignant, the discovery of novel prognostic markers is eagerly awaited. We performed serological identification of antigens by recombinant cDNA expression cloning (SEREX) and identified SKI proto-oncogene protein and transmembrane p24 trafficking protein 5 (TMED5) as antigens recognized by serum IgG antibodies in patients with esophageal carcinoma. SKI and TMED5 proteins were expressed in Escherichia coli, purified by affinity chromatography, and used as antigens. The serum anti-SKI antibody (s-SKI-Ab) and anti-TMED5 antibody (s-TMED5-Ab) levels were significantly higher in 192 patients with esophageal carcinoma than in 96 healthy donors. The presence of s-SKI-Abs and s-TMED5-Abs in the patients' sera was confirmed by western blotting. Immunohistochemical staining showed that the TMED5 protein was highly expressed in the cytoplasm and nuclear compartments of the esophageal squamous cell carcinoma tissues, whereas the SKI protein was localized predominantly in the nuclei. Regarding the overall survival in 91 patients who underwent radical surgery, the s-SKI-Ab-positive and s-TMED5-Ab-negative statuses were significantly associated with a favorable prognosis. Additionally, the combination of s-SKI-Ab-positive and s-TMED5-Ab-negative cases showed an even clearer difference in overall survival as compared with that of s-SKI-Ab-negative and s-TMED5-Ab-positive cases. The s-SKI-Ab and s-TMED5-Ab biomarkers are useful for diagnosing esophageal carcinoma and distinguishing between favorable and poor prognoses.

Changes in roller skiing economy among Nordic combined athletes leading up to the competition season.

The purpose of this study was to compare roller skiing economy during different training phases in Nordic combined (NC) athletes and determine the aerobic and anaerobic factors responsible for changes in skiing economy. Seven elite NC athletes underwent incremental load tests on a large buried treadmill in both spring and autumn using roller skis. Measurements included oxygen uptake, respiratory exchange ratio, and blood lactate concentration. Roller skiing economy was calculated from aerobic and anaerobic energy system contributions, and overall roller skiing economy was determined by combining the two. Comparisons were made between the skiing economies obtained in the two measurement sessions. Physical characteristics and incremental test performance remained consistent between the two measurement sessions. The overall skiing economy at each speed significantly improved toward the competition season (p < 0.05). Similarly, the contribution of anaerobic energy system at each speed showed significant improvement (p < 0.05). In contrast, the contribution of aerobic energy system did not change between the two measurement sessions. This study reveals that NC athletes enhance their skiing economy at the same speed during submaximal efforts in preparation for the competition season. This improvement is predominantly associated with an improvement in the contribution of anaerobic energy system.

Distributed IMU Sensors for In-Field Dynamic Measurements on an Alpine Ski.

Modern ski design is an inherently time-consuming process that involves an iterative feedback loop comprised of design, manufacturing and in-field qualitative evaluations. Additionally consumers can only rely on qualitative evaluation for selecting the ideal ski, and due to the variation in skier styles and ability levels, consumers can find it to be an inconsistent and expensive experience. We propose supplementing the design and evaluation process with data from in-field prototype testing, using a modular sensor array that can be ported to nearly any ski. This paper discusses a new distributed Inertial Measurement Unit (IMU) suite, including details regarding the design and operation, sensor validation experiments, and outdoor in-field testing results. Data are collected from a set of spatially distributed IMUs located on the upper surface of the ski. We demonstrate that this system and associated post-processing algorithms provide accurate data at a high rate (>700 Hz), enabling the measurement of both structural and rigid ski characteristics, and are robust to repetitive testing in outdoor winter conditions.

Bilateral Dorsal Nail Curvature of the Thumb Distal Phalanx - A Case Report.

Congenital dorsal curvature of the distal phalanx has been previously described as 'reverse Kirner' or 'ski-jump' deformity. This report describes bilateral occurrence in the thumbs. A 13-year-old male presented with difficulty caring for his thumbnails and in picking up small objects. Examination showed dorsal curvature of the distal phalanges of both thumbs, with greater curvature of the right side. Radiographs showed wedge-shaped epiphyses and dorsal curvature without coronal plane deviation of the distal phalanges. There was objective and subjective decrease in function associated with lateral pinch and tripod grasp. The reported aetiopathogenesis for Kirner deformity cannot explain the observed dorsal curvature. The bilateral nature makes a secondary physeal cause unlikely and suggests an embryologic basis. Due to the noticeable deficits in function, operative intervention may be warranted. Level of Evidence: Level V (Therapeutic).

TDG generation in a ski-jump spillway with a fully or partial-flip bucket.

Ski-jump spillways are frequently used as discharge structures for high dams during floods with high energy heads. The selection of bucket types at the end of spillways has a pronounced effect on the hydraulics of jet characteristics, such as trajectories and entrained air features. However, there is no literature reporting how changes in the bucket types influence TDG generation. This study compares the hydraulic characteristics and TDG mass transfer properties of a hydraulic project under construction using both the traditional fully-flip bucket and the partial-flip bucket configurations. The results indicate that, the use of the partial-flip bucket at the end of the spillway significantly disperses the water flow and yields better energy dissipation effects. At low flow rates (lower than 400 m3/s for the dam in this study), there is little difference in the downstream TDG saturation between the traditional fully-flip bucket and the partial-flip bucket, the average difference is 1.6 % in three cases with a low flow rate. However, at high flow rates (higher than 400 m3/s), the partial-flip bucket generates more TDG compared to the traditional fully-flip bucket, reaching up to 6.2 % at the maximum flow rate. This phenomenon stems from significant changes in the hydrodynamics of the stilling basin at high flow rates due to variations in the flip bucket type. When strict control of TDG generation is necessary downstream of dams, the use of the partial-flip bucket should be carefully considered. This is because, at high flow rates, the partial-flip bucket might result in higher TDG saturation than the fully-flip bucket.

Ski ameliorates synovial cell inflammation in monosodium iodoacetate-induced knee osteoarthritis.

Knee osteoarthritis (KOA) is one of the most common degenerative diseases and is characterized by cartilage degeneration, synovial inflammation, joint stiffness and even loss of motor function. In the clinical treatment of arthritis, conventional analgesic and anti-inflammatory drugs have great side effects. We have evaluated the possibility of the endogenous transcription regulator Ski as an anti-inflammatory alternative in OA through experimental studies in animal models and in vivo and in vitro. Male Sprague‒Dawley rats were injected with monosodium iodoacetate (MIA) into the knee joints to induce symptoms identical to those of human OA. We isolated knee synovial tissue under sterile conditions and cultured primary synovial cells. In vitro, Ski inhibits the proinflammatory factors IL-1ß, IL-6 and TNF-α mRNA and protein expression in lipopolysaccharide (LPS)-stimulated fibroblast-like synoviocytes (FLSs) and U-937 cells. In addition, Ski attenuates or inhibits OA-induced synovial inflammation by upregulating the protein expression of the anti-inflammatory factor IL-4 and downregulating the protein expression of downstream molecules related to the NF-κB inflammatory signaling pathway. In vivo, Ski downregulated proinflammatory factors and p-NF-κB p65 in KOA synovial tissue and alleviated pain-related behaviors in KOA rats. These experimental data show that Ski has strong anti-inflammatory activity. Ski is an endogenous factor, and if used in the clinical treatment of OA, the side effects are small. However, the anti-inflammatory mechanism of Ski must be further studied.

Anterior cruciate ligament injuries in elite ski jumping reliably allow return to competition but severely affect future top performance.

PURPOSE: In recent years, anterior cruciate ligament (ACL) injuries have been frequently observed in ski jumping. However, available data in this discipline are very scarce. Therefore, the purpose of this study was to investigate whether an ACL injury in elite-level ski jumping limits the performance level after ACL reconstruction (ACLR). METHODS: Both male and female elite-level ski jumpers from five national A-teams who suffered an ACL injury were identified retrospectively by searching available media reports and Fédération Internationale de Ski (FIS) database. World Cup (WC) results and time-out-of-competition before ACL injury and after ACLR were compared. Only athletes who suffered the injury during or after the 2009-2010 season and who participated in at least one WC competition before the injury were included in this study. The level of athletes' performance from two full seasons before until three seasons after the injury was compared. RESULTS: Eighteen elite-level ski jumpers (11 males/seven females) were eligible for the study. All male and four female athletes returned to professional competition after ACLR. One female athlete ended her career due to prolonged recovery and two have not yet recovered due to a recent injury. The mean return-to-competition (RTC) time was 14.6 months in males and 13.5 months in females. The mean WC placement decreased after the ACL injury: two seasons before injury the mean position was 17.9 ± 11.0 (n = 12), one season before it was 22.4 ± 12.8 (n = 15). After recovery, the mean placement in seasons 1-3 was: 26.4 ± 8.9 (n = 7), 25.7 ± 10.3 (n = 13), 33.6 ± 12.2 (n = 10) (p = 0.008). Among the athletes returning to competition, only six males and three females reached their preinjury level and only one male and one female (compared to seven males and three females preinjury) reached an individual top-3 placement after ACLR, accounting for less than 10% of podiums compared to preinjury. CONCLUSION: Only 60% of the professional ski jumpers reached the preinjury level and less than 15% reached a top-3 placement after the ACL injury. These results support the fact that ACL tear during a ski jumping career may be a significant factor limiting high-level performance. In terms of clinical relevance, the findings implicate the need to analyse the reasons of these very low rates of return to elite-level performance, to analyse ACL injury and RTC rates at lower levels of performance and to develop specific prevention strategies in order to reduce the number of ACL injuries in this sport. LEVEL OF EVIDENCE: Level IV.