Force-Velocity Relationship in Cycling and Arm Cranking: A Comparison of Men and Women.

This study was aimed at comparing the force-velocity relationship during cycling and arm cranking in males and females. Thirty-two male and twenty-two female healthy volunteers performed a force-velocity test on a cycle ergometer and a cranking ergometer in a randomly selected order. The theoretical values of the maximum force at zero speed (F0) and the maximum velocity at zero braking force (v0) for the lower and upper limbs were determined, and the maximum anaerobic power (Pmax) was calculated from the individual force-velocity relationship. The Pmax and F0 of the upper limbs related to the lower limbs correspond to 78.2 ± 14.3% and 80.1 ± 17.3% in men and 65.5 ± 12.5% and 74.5 ± 6.5% in women, respectively. The theoretical maximum velocity v0 of the upper limbs to the lower limbs attained 129.1 ± 29.0% in men and 127.4 ± 26.4% in women. The results of the study can serve as reference data for the force-velocity characteristics of the upper and lower limbs of male and female athletes. The results can be used both in training and rehabilitation programs, where the starting point is the objectification of possible strength deficits in various areas of the force-velocity characteristic spectrum of the muscles of the upper and lower limbs.

Effects of soccer training in muscular strength: a comparative study in trained youth soccer players and untrained boys of the same biological age.

BACKGROUND: It is not clear if soccer training affected the development of muscle strength positively in children. We hypothesize that soccer training could positively affect the isokinetic concentric muscle strength and anthropometric characteristics in different ages of adolescents of the same biological age. METHODS: A total of 126 young soccer players (N.=66) and untrained boys (N.=60) throughout the developmental ages of 12, 14 and 16 years volunteered to participate in the study. Sexual maturation was classified according to Tanner's stages. Soccer players, except from their school's physical education program, participate also in a soccer training program. All participants underwent anthropometric measurements. The isokinetic-concentric peak torque values of the hamstrings (H) and quadriceps (Q), as well as the conventional strength ratios of H:Q, were measured on an isokinetic dynamometer at angular velocities of 60, 180, and 300°·s-1. RESULTS: Anthropometric differences in the same age group, between trained and untrained, were presented only for 12-year-olds (height, P<0.001 and BMI, P<0.01). Between groups, differences were observed in almost all anthropometric measurements, probably as result of development. The absolute isokinetic-concentric muscle strength was significantly higher (P<0.001) in the 12- and 16-year-old trained group, compared to untrained, for the knee-flexors and knee-extensors. However, no significant differences were found between the trained and untrained 14-year-olds, for the muscle groups of Q and H. The H:Q strength ratios did not differ between groups at all angular velocities. CONCLUSIONS: The results of this study showed that systematic soccer training has a positive effect in the peripheral system, expressed as an increased lower limb muscle strength; specifically, Q and H.

The effects of soccer training in aerobic capacity between trained and untrained adolescent boys of the same biological age.

BACKROUND: The purpose of this study was to examine the effects of soccer training on maximal oxygen uptake and anthropometric characteristics in different ages of soccer players and untrained adolescents of the same biological age. METHODS: A total of one hundred and twenty-six (N.=126) young soccer players and untrained boys throughout the developmental ages of 12 (soccer players N.=22; untrained boys = 22) 14 (soccer players N.=20; untrained boys = 18) and 16 (soccer players N.=22; untrained boys = 22) volunteered to participate in the study. Sexual maturation was classified according to Tanner's stages. Soccer players participated both in their school's physical education program and in a soccer training program, while the untrained participated only in their school's physical education program. All participants underwent anthropometric measurements and performed a maximal exercise test on a motor driven treadmill to determine maximal oxygen uptake (V̇O2max) and cardiorespiratory indices. Blood lactate (BL) concentration was determined in the 5th minute of recovery using a lactate photometer. RESULTS: The trained group showed significantly higher V̇O2max, in absolute and relative values (P<0.001), BLmax (P<0.05) and maximal respiratory exchange ratio (RERmax) (P<0.05) compared to the untrained group. Resting heart rate (HR) and systolic blood pressure were significantly lower (P<0.05) for the trained compared to untrained. CONCLUSIONS: The results of this study showed that systematic soccer training has a positive effect in the central cardiovascular system expressed as V̇O2max, HR and blood pressure.

Myosin heavy chain isoform composition in the deltoid and vastus lateralis muscles of elite handball players.

The purpose of the present study was to compare the myosin heavy chain (MHC) isoform composition of the deltoid and vastus lateralis muscles of the dominant and non-dominant limbs in handball players. Eleven male Greek elite handball players (age 22.6 ± 1.9 yrs, training experience 10.6 ± 2.1 yrs, height 184.1 ± 4.1 cm, and weight 81.0 ± 12.5 kg) participated in the study. Four muscle biopsies were obtained from the dominant and non-dominant deltoid and vastus lateralis muscles during the in-season period. The MHC composition was determined using SDS-PAGE. No significant difference was found between the dominant and non-dominant muscles; Deltoid muscle: MHC I [(95%CI = -1.22, 0.33), P = 0.228], MHC ΙΙa [(95%CI = -0.32, 1.59), P = 0.168] and MHC IIx [(95%CI = -1.49, 1.10), P = 0.749]; Vastus lateralis muscle: MHC I [(95%CI = -0.38, 0.63), P = 0.586], MHC ΙΙa [(95%CI = -0.50, 0.65), P = 0.783] and MHC IIx [(95%CI = -1.08, 0.42), P = 0.355]. The findings of the present study indicate that the greater use of the dominant limbs for throwing actions and body movements in handball do not lead to altered MHC isoform composition compared to the non-dominant limbs.

The Russians Are the Fastest in Marathon Cross-Country Skiing: The "Engadin Ski Marathon".

It is well known that athletes from a specific region or country are dominating certain sports disciplines such as marathon running or Ironman triathlon; however, little relevant information exists on cross-country skiing. Therefore, the aim of the present study was to investigate the aspect of region and nationality in one of the largest cross-country skiing marathons in Europe, the "Engadin Ski Marathon." All athletes (n = 197,125) who finished the "Engadin Ski Marathon" between 1998 and 2016 were considered. More than two-thirds of the finishers (72.5% in women and 69.6% in men) were Swiss skiers, followed by German, Italian, and French athletes in both sexes. Most of the Swiss finishers were from Canton of Zurich (20.5%), Grisons (19.2%), and Berne (10.3%). Regarding performance, the Russians were the fastest and the British the slowest. Considering local athletes, finishers from Canton of Uri and Glarus were the fastest and those from Canton of Geneva and Basel the slowest. Based on the findings of the present study, it was concluded that local athletes were not the fastest in the "Engadin Ski Marathon." Future studies need to investigate other cross-country skiing races in order to find the nationalities and regions of the fastest cross-country skiers.

Globally Optimal Hand-Eye Calibration Using Branch-and-Bound.

This paper introduces a novel solution to the hand-eye calibration problem. It uses camera measurements directly and, at the same time, requires neither prior knowledge of the external camera calibrations nor a known calibration target. Our algorithm uses branch-and-bound approach to minimize an objective function based on the epipolar constraint. Further, it employs Linear Programming to decide the bounding step of the algorithm.Our technique is able to recover both the unknown rotation and translation simultaneously and the solution is guaranteed to be globally optimal with respect to the L∞-norm.

Effect of a Six-Week Preparation Period on Acute Physiological Responses to a Simulated Combat in Young National-Level Taekwondo Athletes.

The aim of this study was to examine changes in physical attributes, physiological characteristics and responses that occurred in a simulated combat during a six-week preparatory period in young taekwondo athletes. Seven athletes (age 12.17 ± 1.11 years) were examined before (pre-intervention) and after (post-intervention) a preparatory period for physical fitness and physiological responses to a 2×90 s simulated bout with a 30 s rest period. The heart rate (HR) was monitored during the simulated combat, and handgrip muscle strength (HMS) along with the countermovement jump (CMJ) were recorded before and after the combat. When compared with pre-intervention values, in post-intervention we observed a decrease in body mass, body fat percentage, and the HR at rest and during recovery after a 3 min step test, and an increase in maximal velocity of the cycle ergometer force-velocity test, the CMJ and mean power during the 30 s continuous jumping test (p<0.05). Furthermore, HR responses to a simulated combat were lower in the post-intervention session (p<0.05). CMJ values increased after the bout in both pre and post-intervention, with higher absolute values in the latter case (p<0.05), whereas there was no difference in HMS. Based on these findings, it can be concluded that the acute physiological responses to a simulated taekwondo combat vary during a season, which might be explained by changes in physical fitness.

The RIP1-kinase inhibitor necrostatin-1 prevents osmotic nephrosis and contrast-induced AKI in mice.

The pathophysiology of contrast-induced AKI (CIAKI) is incompletely understood due to the lack of an appropriate in vivo model that demonstrates reduced kidney function before administration of radiocontrast media (RCM). Here, we examine the effects of CIAKI in vitro and introduce a murine ischemia/reperfusion injury (IRI)-based approach that allows induction of CIAKI by a single intravenous application of standard RCM after injury for in vivo studies. Whereas murine renal tubular cells and freshly isolated renal tubules rapidly absorbed RCM, plasma membrane integrity and cell viability remained preserved in vitro and ex vivo, indicating that RCM do not induce apoptosis or regulated necrosis of renal tubular cells. In vivo, the IRI-based CIAKI model exhibited typical features of clinical CIAKI, including RCM-induced osmotic nephrosis and increased serum levels of urea and creatinine that were not altered by inhibition of apoptosis. Direct evaluation of renal morphology by intravital microscopy revealed dilation of renal tubules and peritubular capillaries within 20 minutes of RCM application in uninjured mice and similar, but less dramatic, responses after IRI pretreatment. Necrostatin-1 (Nec-1), a specific inhibitor of the receptor-interacting protein 1 (RIP1) kinase domain, prevented osmotic nephrosis and CIAKI, whereas an inactive Nec-1 derivate (Nec-1i) or the pan-caspase inhibitor zVAD did not. In addition, Nec-1 prevented RCM-induced dilation of peritubular capillaries, suggesting a novel role unrelated to cell death for the RIP1 kinase domain in the regulation of microvascular hemodynamics and pathophysiology of CIAKI.

Two independent pathways of regulated necrosis mediate ischemia-reperfusion injury.

Regulated necrosis (RN) may result from cyclophilin (Cyp)D-mediated mitochondrial permeability transition (MPT) and receptor-interacting protein kinase (RIPK)1-mediated necroptosis, but it is currently unclear whether there is one common pathway in which CypD and RIPK1 act in or whether separate RN pathways exist. Here, we demonstrate that necroptosis in ischemia-reperfusion injury (IRI) in mice occurs as primary organ damage, independent of the immune system, and that mice deficient for RIPK3, the essential downstream partner of RIPK1 in necroptosis, are protected from IRI. Protection of RIPK3-knockout mice was significantly stronger than of CypD-deficient mice. Mechanistically, in vivo analysis of cisplatin-induced acute kidney injury and hyperacute TNF-shock models in mice suggested the distinctness of CypD-mediated MPT from RIPK1/RIPK3-mediated necroptosis. We, therefore, generated CypD-RIPK3 double-deficient mice that are viable and fertile without an overt phenotype and that survived prolonged IRI, which was lethal to each single knockout. Combined application of the RIPK1 inhibitor necrostatin-1 and the MPT inhibitor sanglifehrin A confirmed the results with mutant mice. The data demonstrate the pathophysiological coexistence and corelevance of two separate pathways of RN in IRI and suggest that combination therapy targeting distinct RN pathways can be beneficial in the treatment of ischemic injury.

Medical professionalism, revenue enhancement, and self-interest: an ethically ambiguous association.

This article explores the association between medical professionalism, revenue enhancement, and self-interest. Utilizing the sociological literature, I begin by characterizing professionalism generally and medical professionalism particularly. I then consider "pay for performance" mechanisms as an example of one way physicians might be incentivized to improve their professionalism and, at the same time, enhance their revenue. I suggest that the concern discussed in much of the medical professionalism literature that physicians might act on the basis of self-interest is over-generalized, and that instead we ought to argue about ways to distinguish permissible and impermissible self-interested actions. Also, I argue that financial incentives for medical professionals ought to be permissible but considered as "by-products" of doing what physicians are expected to do as professionals in any case. Nevertheless, I conclude that, even if a positive association between increasing professionalism and revenue enhancement can be established, in the long term it may not be an unambiguous good for physicians as professionals in that this association may tend to reduce their professional discretion.

Cardiorespiratory and metabolic alterations during exercise and passive recovery after three modes of exercise.

The objective of this study was to investigate the potential variations in cardiorespiratory and metabolic parameters and running performance among 3 modes of exercise of the same duration, namely, intermittent running with active recovery (AR) or passive recovery (PR) and continuous running (CR) and whether these variations could affect passive recovery time (PRT). Fifteen male physical education students with a subspecialty in soccer were studied (mean age 22.3 ± 2.5 years, training experience 12.3 ± 2.5 years) in the middle of the playing season. The results showed that during exercise, the highest heart rate (HR) and VO2 values were observed in CR, whereas the lowest values in PR followed by AR. Blood lactate (BLa) concentration was higher in PR by 38% compared to that in AR (p < 0.05). The exercise duration was similar between PR and AR tests and longer than in CR. With regard to PRT, the highest HR (186 ± 9 b · min(-1)), VO2 (55.5 ± 5.2 ml · kg(-1) · min(-1)), and BLa (5.1 ± 1.7 mmol · L(-1)) values were found in CR. No differences in HR and VO2 between PR and AR were detected. However, despite the differences in BLa concentration between AR and PR during exercise, the PRT BLa values between these 2 exercise modes were not different. Among the 3 running protocols, only CR appeared to have fully challenged the cardiorespiratory system inducing maximal HR and VO2 responses during exercise and high BLa values in PRT, yet these responses were not associated with better exercise performance compared to intermittent running. Therefore, intermittent exercise, regardless of implementing passive or active interval, might be the preferable exercise mode particularly in activities extended over 30 minutes.

The effect of different exercise-testing protocols on atrial natriuretic peptide.

The aim of this study was to examine and to compare alterations in the secretion of atrial natriuretic peptide (ANP) during different exercise-testing protocols in moderately trained men. Fifteen healthy male physical education students were studied (mean age 22·3 ± 2·5 years, training experience 12·3 ± 2·5 years, height 1·80 ± 0·06 m, weight 77·4 ± 8·2 kg). Participants performed an initial graded maximal exercise testing on a treadmill for the determination of VO(2max) (duration 7·45-9·3 min and VO(2max) 55·05 ± 3·13 ml kg(-1) min(-1) ) and were examined with active recovery (AR), passive recovery (PR) and continuous running (CR) in random order. Blood samples for plasma ANP concentration were taken at rest (baseline measurement), immediately after the end of exercise as well as after 30 min in passive recovery time (PRT). The plasma ANP concentration was determined by radioimmunoassay (RIA). The results showed that ANP plasma values increased significantly from the rest period to maximal values. In the short-term graded maximal exercise testing the ANP plasma values increased by 56·2% (44·8 ± 10·4 pg ml(-1) versus 102·3 ± 31·3 pg ml(-1) , P<0.001) and in the CR testing the ANP levels increased by 29·2% (44·8 ± 10·4 pg ml(-1) versus 63·3 ± 19·8 pg ml(-1) , P<0.001) compared to the baseline measurement. Moreover, the values of ANP decreased significantly (range 46·4-51·2%, P<0.001) in PRT after the end of the four different exercise modes. However, no significant difference was evident when ANP values at rest and after AR and PR were compared. It is concluded that the exercise testing protocol may affect the plasma ANP concentrations. Particularly, short-term maximal exercise significantly increases ANP values, while the intermittent exercise form of active and passive recovery decreases ANP concentrations.

Discussing the theological grounds of moral principles.

Discussing the theological beliefs that ground Catholic moral principles can make some people uncomfortable, even while others will appreciate it. But these reactions will sometimes be revealed not as the emotions they are, but as objections to the relative independence or dependence of morality on foundational beliefs. In the end, context should dictate whether one displays the theological beliefs that ground Catholic moral principles.