Changes in power assessed by the Wingate anaerobic test following downhill running

Few studies have examined the effects of eccentric exercise-induced muscle damage on power despite power being a key performance variable in a number of sporting events. The aim of this study was to examine changes in anaerobic power (30-second Wingate Test), isometric strength of the knee extensors and flexors, muscle soreness, and plasma creatine kinase (CK) activity following downhill running. Eight men performed a 40-minute downhill (-7%) run on a treadmill, and measurements were taken on 6 occasions (2 baseline and 0.5, 24, 72, and 120 hours postrun). A second group of men (n = 5) had the measurements taken on 6 occasions without downhill running and served as a control group. A repeated measures analysis of variance revealed no significant changes in any measures across time for the control group. Following downhill running, significant (p < 0.05) decreases in strength (0.5–24 hours), and significant increases in muscle soreness (0.5–72 hours) and plasma CK activity (0.5–120 hours) were observed. A significant decrease in peak and average power (~5%) was evident only 0.5 hours postrun, and the decrease was smaller in magnitude than that of strength (~15%). These results suggest that power is less affected than strength after eccentric exercise, and the effect of reduced power on sport performance seems negligible

Delayed onset muscle soreness at one day after one-leg eccentric cycling in relation to decreases in muscle function immediately post-exercise

This study investigated the relationship between muscle function decrease at immediately post-exercise and DOMS at 24h after eccentric cycling..

Upstream activation element of the PH03 gene encoding for thiamine-repressible acid phosphatase in Saccharomyces cerevisiae

AbstractThe PH03 gene of Saccharomyces cerevisiae encodes thiamine-repressible acid phosphatase and requires the positively acting regulatory protein TH12 for its expression. Deletion analysis of the 5′-flanking region of PH03 gene revealed that an activating region located at nucleotide position −234 to −215 relative to the translation initiation codon is required for the expression and sensitivity to thiamine. A chemically synthesized DNA fragment covering −234 to −215 showed a significant level of expression when inserted in front of the PH03 promoter lacking the activating region. Electrophoretic mobility shift assay demonstrated the presence of proteins that bound to the above DNA fragment in the nuclear extract from cells grown in thiamine-free medium. These findings suggested that this region between −234 and −215 acts as an upstream activation element of the PH03 gene that can interact with regulatory proteins

Exercise-induced mechanical hypoalgesia in musculotendinous tissues of the lateral elbow

The aim of this study was to investigate mechanical sensitivity responses at the lateral elbow to repeated weekly bouts of low load exercise in healthy subjects. Thirteen young men (n = 6) and women participated in 4 weeks of exercise. Arms were randomly allocated to an eccentric-only exercise protocol (ECC: 5 sets of 20 contractions) or to a concentric–eccentric protocol (CON-ECC: 5 sets of 10 eccentric/10 concentric contractions) performed at 30% maximal wrist extension force. Arms were exercised consecutively within each supervised weekly session. Quantitative measures of pressure pain threshold (PPT) recorded at three sites and maximal force for grip and wrist extension were assessed at baseline, and immediately pre/post exercise at each session. Muscle endurance during 100 maximal grip contractions force was assessed at baseline and one week following the final exercise session. Results showed that regardless of protocol, repeated low load exercise resulted in a time-dependent increase in PPT at all sites post exercise Weeks 3 and 4 and persisting at follow up Week 5 (P \u3c 0.02). No significant difference between protocols was evident for any measure. Muscle force and endurance were not significantly augmented compared with baseline. In conclusion mechanical hypoalgesia is induced by repeated low load exercises regardless of exercise mode, and this may prove beneficial if replicated clinically

Influence of age and sex on pacing during Sprint, Olympic, Half-Ironman and Ironman triathlons: Part B

The aim of this study was to investigate the influence of biological sex and age on the pacing strategies adopted by non-drafting top triathletes during the cycle and run disciplines of a Sprint, Olympic, half-Ironman and Ironman triathlon. Split times of the top 20% non-elite males (n=468) and females (n=146) were determined using official race transponders and a video capture system for pre-determined sections of the cycle and run disciplines of four triathlon distances. Indices of pacing were calculated to compare between sexes and age-groups. Results of this study indicated that different pacing strategies were adopted between athletes of different age and sex over the various triathlon disciplines and distances. Females were more aggressive during the initial stages of the cycling discipline across all distances (sprint - 2.1% p=0.024; Olympic - 1.6%, p=0.011; half-Ironman- 1.5%, p<0.001; Ironman - 1.7%, p<0.001 higher relative to mean) compare with males. Younger athletes (20-29 y) tend to begin the run faster (2.0 to 3.0% faster than other age-groups, p<0.029) during the sprint, Olympic and half-Ironman triathlons. These results indicate that different pacing strategies are adopted by non-drafting top athletes of different age and sex. Optimal pacing strategies may differ between sex and ages; therefore individuals may need to trial different strategies to develop their own optimal pacing profile for triathlon events of varying distances

Influence of race distance and biological sex on age-related declines in triathlon performance: Part A

This study examined the effect of biological sex and race distance on the age-related declines in swimming, cycling, running and overall performances of the sprint, Olympic, Half-Ironman and Ironman triathlons. Individual discipline and overall performance time of the top 20% non-elite males (n=468) and females (n=146) were compared by categorizing into four 10-year age-groups (20-29, 30-39, 40-49, 50+ years) and normalising to the mean performance time of the fastest age-group for each race. An earlier, larger and faster rate of decline (p=0.01) in performance with ageing was observed in females (≥30 years, 9.3%, 3.0% per decade respectively) and males (≥40 years, 5.9%, 2.2% per decade, respectively) for the longer events (half-Ironman and Ironman) compared with the shorter distances (sprint and Olympic, ≥50 years for both sexes). A greater magnitude of decline was observed in swimming for both sexes, especially in the longer events, when compared with cycling and running (12.8%, 5.6%, 9.3% for females, 9.4%, 3.7%, 7.3% for males, in the swim, cycle and run disciplines, respectively). These results indicate that both race distance and biological sex influence the age-related decline in triathlon performance and could aid athletes in optimising training programs to attenuate the age-related declines in performance across different disciplines and distances. Specifically, older athletes may benefit from greater emphasis on swim training and factors that may influence performance during longer distance triathlons

Effects of isometric quadriceps strength training at different muscle lengths on dynamic torque production

This study aims to (1) determine whether isometric training at a short vs. long quadriceps muscle length affects concentric torque production; (2) examine the relationship between muscle hypertrophy and concentric torque; and (3) determine whether changes in fascicle length are associated with changes in concentric torque. Sixteen men performed isometric training at a short (SL, n = 8) or a long muscle length (LL, n = 8). Changes in maximal concentric torque were measured at 30, 60, 90, 120, 180, 240 and 300 rad · s−1. The relationships between the changes in concentric torque, cross-sectional area, volume and fascicle length were tested. Concentric torque increased significantly after training only in LL and at angular velocities of 30 and 120 rad · s−1 by 12–13% (P < 0.05). Muscle size increased in LL only, the changes were correlated (r = 0.73–0.93, P < 0.05) with the changes in concentric torque. Vastus lateralis (VL) fascicle length increased in both groups (5.4 ± 4.9%, P = 0.001) but the change was not correlated with changes in concentric torque in either group. Isometric training-induced increases in muscle size and concentric torque were best elicited by training at long muscle lengths. These results highlight a clear muscle length dependence of isometric training on dynamic torque production

Hyperthermic fatigue precedes a rapid reduction of serum sodium and cramping in an ironman triathlete

We present two original observations. First, we document the attainment of a critically high internal body temperature in a triathlete performing in an Ironman triathlon that we believe directly influenced his ability to run fast. Second, this athlete experienced an unusually rapid reduction in blood sodium (Na+) that preceded cramping, despite presenting signs of dehydration

Comparison between high- and low-intensity eccentric cycling of equal mechanical work for muscle damage and the repeated bout effect

Purpose: We compared high- and low-intensity eccentric cycling (ECC) with the same mechanical work for changes in muscle function and muscle soreness, and examined the changes after subsequent high-intensity ECC. Methods: Twenty men performed either high-intensity ECC (1 min × 5 at 20% of peak power output: PPO) for two bouts separated by 2 weeks (H–H, n = 11), or low-intensity (4 min × 5 at 5% PPO) for the first and high-intensity ECC for the second bout (L–H, n = 9). Changes in indirect muscle damage markers were compared between groups and bouts. Results: At 24 h after the first bout, both groups showed similar decreases in maximal isometric (70° knee angle, − 10.6 ± 11.8%) and isokinetic (− 11.0 ± 8.2%) contraction torque of the knee extensors (KE), squat (− 7.7 ± 10.4%) and counter-movement jump (− 5.9 ± 8.4%) heights (p \u3c 0.05). Changes in KE torque and jump height were smaller after the second than the first bout for both the groups (p \u3c 0.05). Increases in plasma creatine kinase activity were small, and no significant changes in vastus lateralis or intermedius thickness nor ultrasound echo-intensity were observed. KE soreness with palpation was greater (p \u3c 0.01) in H–H (peak: 4.2 ± 1.0) than L–H (1.4 ± 0.6) after the first bout, but greater in L–H (3.6 ± 0.9) than H–H (1.5 ± 0.5) after the second bout. This was also found for muscle soreness with squat, KE stretch and gluteal palpation. Conclusion: The high- and low-intensity ECC with matched mechanical work induced similar decreases in muscle function, but DOMS was greater after high-intensity ECC, which may be due to greater extracellular matrix damage and inflammation. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature

Piccole capitali creative

Nel secolo urbano che abbiamo di fronte, la citt\ue0 sar\ue0 lo scenario della competizione delle energie, delle risorse umane, delle intelligenze collettive e della creativit\ue0 per la costruzione di un\u2019evoluzione pi\uf9 compatibile con le identit\ue0 e le vocazioni e pi\uf9 sostenibile rispetto alle risorse ed alle sensibilit\ue0 del territorio. I segnali delle sue forme, delle sue relazioni e delle sue identit\ue0 sono gi\ue0 evidenti in alcune citt\ue0 del presente ed ad essi sono dedicate numerose ricerche urbanistiche, sociologiche ed economiche. Ma i segnali sono evidenti e trasmettono ispirazioni e stimoli anche a chi osserva la citt\ue0 per mestiere di progettista, di pianificatore, di stratega dello sviluppo. Il XXI secolo sar\ue0 l\u2019era indiscussa delle citt\ue0 e su di esse si misurer\ue0 lo sviluppo delle nazioni. Per la prima volta, pi\uf9 della met\ue0 della popolazione mondiale vivr\ue0 nelle citt\ue0, in Europa oggi la cifra \ue8 gi\ue0 di oltre il 75%, e nei paesi in via di sviluppo raggiunger\ue0 velocemente il 50%. Il mondo si svilupper\ue0 sia attorno a grandi megalopoli da decine di milioni di abitanti, ma anche attorno a citt\ue0 metropolitane, a conurbazioni diffuse e ad armature di micropoli: all\u2019armatura urbana delle citt\ue0 globali si annoder\ue0, soprattutto in Europa, l\u2019armatura delle citt\ue0 di secondo livello, produttrici di visioni alternative rispetto all\u2019esplosione delle megalopoli. L\u2019armatura urbana europea di secondo livello \u2013 le piccole capitali, sempre pi\uf9 citt\ue0-porta \u2013 si delinea come annodata attorno a \u201ccitt\ue0 della cultura\u201d, nel senso di citt\ue0 non solo detentrici di risorse culturali profonde lasciate dal palinsesto della storia, ma anche produttrici di nuova cultura: le culture-based competition cities saranno, infatti, quelle citt\ue0 in grado di competere nel panorama internazionale attraverso la valorizzazione e la promozione della propria identit\ue0 culturale, sia consolidata che in evoluzione