INTEGRATIVE PHYSIOLOGICAL AND BIOMECHANICAL ASPECTS IN COMPETITIVE CROSS-COUNTRY SKIING

Cross-country skiing involves a large variety of skiing techniques. Among these double poling (DP) has markedly increased in importance during the last decade, accentuated by new racing events with higher racing velocity. The aims with the present studies were to describe DP using an integrative physiological and biomechanical approach

Journal Staff

This study is on how leg utilisation may affect skiing efficiency and performance in double-poling ergometry. Three experiments were conducted, each with a different style of the double-poling technique: traditional with small knee range-of-motion and fixed heels (TRAD); modern with large knee range-of-motion and fixed heels (MOD1) and modern with large knee range-of-motion and free heels (MOD2). For each style, motion data were extracted with automatic marker recognition of reflective markers and applied to a 3D full-body musculoskeletal simulation model. Skiing efficiency (skiing work divided by metabolic muscle work) and performance (forward impulse) were computed from the simulation output. Skiing efficiency was 4.5%, 4.1% and 4.1% for TRAD, MOD1 and MOD2, respectively. Performance was 111, 143 and 149Ns for TRAD, MOD1 and MOD2, respectively. Thus, higher lower body utilisation increased the performance but decreased the skiing efficiency. These results demonstrate the potential of musculoskeletal simulations for skiing efficiency estimations.This study was sponsored in part by the Swedish National Centre for Research in Sports (Grant No. 168/09). The Swedish Winter Sports Research Centre provided laboratory resources.Beräkningsbaserad biomekanik inom längdskidåkning - möjligheter och begränsninga

Läkemedelsdistributionen i Norden. En komparativ studie av aktörer, resurser och aktiviteter.

This paper reports on a preliminary studie of the organising of pharmaceutical goods distribution in the Nordic countries. Based on close descriptions of the four national markets, Sweden, Denmark, Norway and Finland, a comparative analysis is made. The chosen comparative dimensions are: activity structures and actor constellations; vertical and horisontal integration; service levels; and pricing system. Despite their apparent similarities the four national markets display many differences in these dimensions. Further, within each national market, there are considerable differences between how the distribution operations are described in principle and how they appear when observed in practice.pharmaceuticals; goods distribution; market re-regulation; pricing

Antitrust, the Gig Economy, and Labor Market Power

The purpose of the current study was to develop and validate an automatic algorithm for classification of cross-country (XC) ski-skating gears (G) using Smartphone accelerometer data. Eleven XC skiers (seven men, four women) with regional-to-international levels of performance carried out roller skiing trials on a treadmill using fixed gears (G2left, G2right, G3, G4left, G4right) and a 950-m trial using different speeds and inclines, applying gears and sides as they normally would. Gear classification by the Smartphone (on the chest) and based on video recordings were compared. Formachine-learning, a collective database was compared to individual data. The Smartphone application identified the trials with fixed gears correctly in all cases. In the 950-m trial, participants executed 140 ± 22 cycles as assessed by video analysis, with the automatic Smartphone application giving a similar value. Based on collective data, gears were identified correctly 86.0% ± 8.9% of the time, a value that rose to 90.3% ± 4.1% (P < 0.01) with machine learning from individual data. Classification was most often incorrect during transition between gears, especially to or from G3. Identification was most often correct for skiers who made relatively few transitions between gears. The accuracy of the automatic procedure for identifying G2left, G2right, G3, G4left and G4right was 96%, 90%, 81%, 88% and 94%, respectively. The algorithm identified gears correctly 100% of the time when a single gear was used and 90% of the time when different gears were employed during a variable protocol. This algorithm could be improved with respect to identification of transitions between gears or the side employed within a given gear

Instant Biofeedback Provided by Wearable Sensor Technology Can Help to Optimize Exercise and Prevent Injury and Overuse

Source at https://doi.org/10.3389/fphys.2017.00167 With great interest, we have been following the developing variety and popularity of commercially available wearable sensor technologies, as well as the discussion concerning their usefulness for improving fitness and health (Duking et al., 2016; Halson et al., 2016; Sperlich and Holmberg,2016). Although many of these devices may not necessarily fulfill scientific criteria for quality (Sperlich and Holmberg, 2016) or may pose a threat to the security of personal data (Austen, 2015 ), we would like to emphasize here that many individuals who seek to improve their health or physical performance do so on their own, without the guidance of professionals to design their fitness training. Although professional guidance is, of course, important, such individuals and, especially beginners, would find instantaneous (bio)feedback beneficial for optimal adaptation and prevention of overuse or injury. We believe wearable sensor technologies, in conjunction with appropriate (mobile) applications, data mining and machine learning algorithms, can provide biofeedback that is useful in many ways

Modeling Optimal Cadence as a Function of Time during Maximal Sprint Exercises Can Improve Performance by Elite Track Cyclists

In track cycling sprint events, optimal cadence PRopt is a dynamic aspect of fatigue. It is currently unclear what cadence is optimal for an athlete’s performance in sprint races and how it can be calculated. We examined fatigue-induced changes in optimal cadence during a maximal sprint using a mathematical approach. Nine elite track cyclists completed a 6-s high-frequency pedaling test and a 60-s isokinetic all-out sprint on a bicycle ergometer with continuous monitoring of crank force and cadence. Fatigue-free force-velocity (F/v) and power-velocity (P/v) profiles were derived from both tests. The development of fatigue during the 60-s sprint was assessed by fixing the slope of the fatigue-free F/v profile. Fatigue-induced alterations in PRopt were determined by non-linear regression analysis using a mono-exponential equation at constant slope. The study revealed that PRopt at any instant during a 60-s maximal sprint can be estimated accurately using a mono-exponential equation. In an isokinetic mode, a mean PRopt can be identified that enables the athlete to generate the highest mean power output over the course of the effort. Adding the time domain to the fatigue-free F/v and P/v profiles allows time-dependent cycling power to be modelled independent of cadence

Private Equity Firms as Gatekeepers

Notwithstanding the considerable attention private equity receives, there continues to be substantial confusion about what private equity does and whether this creates value. Calls for more aggressive regulation of the industry reflect a skeptical view of private equity as—at best—a zero-sum game, in which profits are generated only at the expense of other constituencies. The standard defense of private equity points to its corporate governance advantages as a source of value. This Article identifies an overlooked and increasingly important way in which private equity creates value: private equity firms act as gatekeepers in the debt markets. As repeat players, private equity firms use their reputations with creditors to mitigate the problems of borrower adverse selection and moral hazard in the companies that they manage, thereby reducing creditors’ costs of lending to these companies. Private equity-owned companies are thus able to borrow money on more favorable terms than standalone companies, all else being equal. By acting as gatekeepers, private equity firms render the debt markets more efficient and provide their portfolio companies with an increasingly valuable borrowing advantage. Ironically, then, debt may well be private equity’s greatest asset

Influence of Course Type on Upper Body Muscle Activity in Elite Cross-Country and Downhill Mountain Bikers During Off Road Downhill Cycling

This study aimed to investigate upper body muscle activity using surface electromyography (sEMG) in elite cross-country (XCO) and downhill (DH) cyclists during off road descending and the influence of man-made (MM) and natural terrain (NT) descents on muscle activity. Twelve male elite mountain bikers (n=6 XCO; age 23 ± 4 yrs; stature 180.5 ± 5.6 cm; body mass 70.0 ± 6.4 kg and n=6 DH; age 20 ± 2 yrs; stature 178.8 ± 3.1 cm; body mass 75.0 ± 3.0 kg) took part in this study. sEMG were recorded from the left biceps brachii, triceps brachii, latissimus dorsi and brachioradialis muscles and expressed as a percentage of maximal voluntary isometric contraction (% MVIC). Both groups performed single runs on different MM and NT courses specific to their cycling modality. Significant differences in mean % MVIC were found between biceps brachii and triceps brachii (p=.016) and triceps brachii and latissimus dorsi (p=.046) during MM descents and between biceps brachii and triceps brachii (p=.008) and triceps brachii and latissimus dorsi (p=.031) during NT descents within the DH group. Significant differences in mean % MVIC were found between biceps brachii and brachioradialis (p=.022) for MM runs and between biceps brachii and brachioradialis (p=.013) for NT runs within the XCO group. Upper body muscle activity differs according to the type of downhill terrain, and appears to be specific to DH and XCO riders. Therefore, the discipline specific impact on muscle activation and the type of course terrain ridden should be considered when mountain bikers engage in upper body conditioning programmes

Production of tumor necrosis factor-α and interleukin-6 in whole blood stimulated by live Gram-negative and Gram-positive bacteria

ObjectiveTo investigate the production of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) induced by live Gram-negative and Gram-positive bacteria in whole blood in vitro.MethodsIn all, 49 different isolates were studied. Each of the 49 different isolates was incubated for 4 h with whole blood at a ratio of one monocyte per 1-5 bacteria. Plasma was then separated and frozen, and the concentrations of TNF-α and IL-6 were measured by enzyme immunoassays.ResultsThere was a positive correlation between TNF-α and IL-6 values, r= 0.9. Gram-negative bacteria induced higher levels of both TNF-α and IL-6 than Gram-positive bacteria. Group G streptococci (GGS) induced higher levels of TNF-α than Streptococcus pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis and group A streptococci (GAS). Klebsiella pneumoniae induced higher levels of TNF-α than Haemophilus influenzae, Escherichia coli and Neisseria meningitidis. GGS induced higher levels of IL-6 than Staphylococcus epidermidis, Staphylococcus aureus and GAS. When the relative amounts of cytokine induced by the strains were compared to serum concentrations measured on admission in patients with bacteremia caused by the same bacterial isolates there was no significant correlation.ConclusionSpecies- and strain-related differences in cytokine-inducing properties were found which may have significance in clinical infections