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Purpose: To investigate the relationship between physical performance tests and on-ice external load from simulated games (scrimmages) in ice hockey. Methods: A total of 14 players completed a physical performance test battery consisting of 30-m sprint test—run and 30-m sprint test—skate (including 10-m split times and maximum speed), countermovement jump, standing long jump, bench press, pull-ups, and trap bar deadlift and participated in 4 scrimmages. External load variables from scrimmages included total distance; peak speed; slow ( 24.0 km/h) speed skating distance; number of sprints; PlayerLoad™; number of high-intensity events (> 2.5 m/s); accelerations; decelerations; and changes of direction. Bayesian pairwise correlation analyses were performed to assess the relationship between physical performance tests and external load performance variables. Results: The results showed strong evidence (Bayes factor > 10) for associations between pull-ups and high-intensity events (τ = .61) and between maximum speed skate and peak speed (τ = .55). There was moderate evidence (Bayes factor >3 to τ = .44) and countermovement jump (τ = .44) with sprint speed skating distance, countermovement jump with number of sprints (τ = .46), pull-ups with changes of direction (τ = .50), trap bar with peak speed (τ = .45), and body mass with total distance (τ = .49). Conclusion: This study found physical performance tests to be associated with some of the external load variables from scrimmages. Nevertheless, the majority of correlations did not display meaningful associations, possibly being influenced by the selection of physical performance tests.

Context: Warming up in very cold climates and maintaining an elevated body temperature prior to a race is challenging for snow-sport athletes. Purpose: To investigate the effects of active (ACT), passive (PAS), and a combination of ACT and PAS (COM) warm-ups on maximal physical performance in a subzero environment among snow-sport athletes. Methods: Ten junior alpine skiers completed 3 experimental trials in −7.2 (0.2)°C. The ACT involved 5 minutes of moderate cycling, 3 × 15-second accelerations, a 6-second sprint, 5 countermovement jumps (CMJs), and a 10-minute passive transition phase, while in PAS, participants wore a lower-body heated garment for 24 minutes. In COM, participants completed the active warm-up, then wore the heated garment during the transition phase. Two maximal CMJs and a 90-second maximal isokinetic cycling test followed the warm-up. Results: CMJ performance was likely (P = .150) and very likely (P = .013) greater in ACT and COM, respectively, versus PAS. Average power output during the cycling test was likely (P = .074) greater in ACT and COM versus PAS. Participants felt likely to almost certainly warmer (P P = .161) during ACT and COM versus PAS. In addition, participants felt likely warmer (P = .136) and very likely more comfortable (P = .161) in COM versus ACT. Conclusions: COM resulted in significantly improved CMJ performance versus PAS while both ACT and COM led to likely improved 90-second cycling performance. Participants felt significantly warmer during ACT and COM versus PAS and likely warmer in COM versus ACT. Therefore, a combined warm-up is recommended for alpine skiers performing in subzero temperatures.

Cadmium (Cd) is non-essential and toxic. Sulfur (S) addition to contaminated soils reduces Cd toxicity in rice and corn. I aimed to determine the underlying mechanisms by which S reduces Cd toxicity in hydroponically- and soil-grown soybean. In the presence of Cd, plant biomass was reduced by ~20%, Cd accumulated up to 45 μg/g in roots and 15 μg/g shoots, and concentrations of Cd chelators increased by more than 10-fold. Addition of S to Cd- treated plants had no effect on plant biomass, concentrations of Cd in roots and shoots, or vacuolar Cd sequestration in the root cortex. While additional S visibly altered Cd localization in the roots, it had no effect on altering Cd concentration in root plaque. Additional S in the presence of Cd resulted in a 0- to 1.5-fold increase in Cd chelator concentrations; however, addition of S to alleviate Cd toxicity has no benefit in soybean.

Purpose: To investigate within-player effect, between-player effect, and individual response of external training load from player tracking devices on session rating of perceived exertion training load (sRPE-TL) in elite football players. Methods: The authors collected sRPE-TL from 18 outfield players in 21 training sessions. Total distance, high-speed running distance (>14.4 m/s), very high-speed running distance (>19.8 m/s), PlayerLoad™, PlayerLoad2D™, and high-intensity events (HIE > 1.5, HIE > 2.5, and HIE > 3.5 m/s) were extracted from the tracking devices. The authors modeled within-player and between-player effects of single external load variables on sRPE-TL, and multiple levels of variability, using a linear mixed model. The effect of 2 SDs of external load on sRPE-TL was evaluated with magnitude-based inferences. Results: Total distance, PlayerLoad™, PlayerLoad2D™, and HIE > 1.5 had most likely substantial within-player effects on sRPE-TL (100%–106%, very large effect sizes). Moreover, the authors observed likely substantial between-player effects (12%–19%, small to moderate effect sizes) from the majority of the external load variables and likely to very likely substantial individual responses of PlayerLoad™, high-speed running distance, very high-speed running distance, and HIE > 1.5 (19%–30% coefficient of variation, moderate to large effect sizes). Finally, sRPE-TL showed large to very large between-session variability with all external load variables. Conclusions: External load variables with low intensity-thresholds had the strongest relationship with sRPE-TL. Furthermore, the between-player effect of external load and the individual response to external load advocate for monitoring sRPE-TL in addition to external load. Finally, the large between-session variability in sRPE-TL demonstrates that substantial amounts of sRPE-TL in training sessions are not explained by single external load variables.

This chapter examines the kinds of agency imputed to machines by the tradition of IT configuration management. While it is rarely examined by social or cultural studies of technology, IT configuration management is of profound importance in the story of cloud computing and recent paradigms of information security. Like infrastructure studies, configuration management took shape in relation to the pragmatics of managing “heterogeneous distributed computing” in the 1990s, and shares with Susan Leigh Star’s early work a concern with the problem of coordination in distributed systems. Given an obsession with figurative imagery in configuration management’s self-descriptions (engines, puppets, conductors, chefs, promises), I ask whether we can detect a shift here in how human-machine relations are figured, from one of control to one of stewardship.

ObjectiveA limited number of studies have explored the external load experienced in indoor sports such as ice hockey, and few the link between training and match performance. As a paucity exists within this topic, this study explored whether a simulated match design (i.e., scrimmage) could be representative of official match demands and elicit similar external loads as in official matches in a group of elite youth male ice hockey players.MethodsA total of 26 players were monitored during eight official and four simulation matches using a Local Positioning System. Total distance, max velocity, slow (0–10.9 km/h), moderate (11–16.9 km/h), high (17.0–23.9 km/h), and sprint (>24 km/h) speed skating distance, distance per min, PlayerLoadTM, PlayerLoadTM per min, high-intensity events (HIEs) (>2.5 m/s−2), acceleration (ACCs), decelerations (DECs), and change of directions (CODs) were extracted from the tracking devices. A two-level regression analysis was conducted to compare the difference between match types when controlling for time on ice, match day, and position.ResultsBetween match-type results showed a credible difference in all variables except max velocity and ACCs. Distance per min was 27.3% higher during simulation matches and was explained by a 21.3, 24.1, and 14.8% higher distance in sprint-, high-, and moderate speed skating distance, while slow speed-skating distance was 49.2% lower and total distance only trivially different from official to simulation matches. Total PlayerLoadTM was 11.2% lower, while PlayerLoadTM per min was 8.5% higher during simulation matches. HIEs, CODs, and DECs were 10.0, 11.9, and 22.3% higher during simulation matches.ConclusionThe simulated match design is related to official match demands with comparable match-time, playing time, number of shifts, and shift duration. However, simulation matches provoked a higher external load output compared with official matches, possibly explained by a more continuous movement design. A game-based simulation match design can therefore be utilized when match-related actions at high intensity are warranted.

Purpose: To investigate the effects of including repeated sprints in a weekly low-intensity (LIT) session during a 3-week transition period on cycling performance 6 weeks into the subsequent preparatory period (PREP) in elite cyclists. Methods: Eleven elite male cyclists (age = 22.0 [3.8] y, body mass = 73.0 [5.8] kg, height = 186 [7] cm, maximal oxygen uptake [VO2max] = 5469 [384] mL·min−1) reduced their training load by 64% and performed only LIT sessions (CON, n = 6) or included 3 sets of 3 × 30-second maximal sprints in a weekly LIT session (SPR, n = 5) during a 3-week transition period. There was no difference in the reduction in training load during the transition period between groups. Physiological and performance measures were compared between the end of the competitive period and 6 weeks into the PREP. Results: SPR demonstrated a 7.3% (7.2%) improvement in mean power output during a 20-minute all-out test at PREP, which was greater than CON (−1.3% [4.6%]) (P = .048). SPR had a corresponding 7.0% (3.6%) improvement in average VO2 during the 20-minute all-out test, which was larger than the 0.7% (6.0%) change in CON (P = .042). No change in VO2max, gross efficiency, or power output at blood lactate concentration of 4 mmol·L−1 from competitive period to PREP occurred in either group. Conclusion: Including sprints in a weekly LIT session during the transition period of elite cyclists provided a performance advantage 6 weeks into the subsequent PREP, which coincided with a higher performance VO2.

Team handball matches place diverse physical demands on players, which may result in fatigue and decreased activity levels. However, previous speed-based methods of quantifying player activity may not be sensitive for capturing short-lasting team-handball-specific movements.Purpose:To examine activity profiles of a women’s team handball team and individual player profiles, using inertial measurement units.Methods:Match data were obtained from 1 women’s national team in 9 international matches (N = 85 individual player samples), using the Catapult OptimEye S5. PlayerLoad/min was used as a measure of intensity in 5- and 10-min periods. Team profiles were presented as relative to the player’s match means, and individual profiles were presented as relative to the mean of the 5-min periods with >60% field time.Results:A high initial intensity was observed for team profiles and for players with ≥2 consecutive periods of play. Substantial declines in PlayerLoad/min were observed throughout matches for the team and for players with several consecutive periods of field time. These trends were found for all positional categories. Intensity increased substantially in the final 5 min of the first half for team profiles. Activity levels were substantially lower in the 5 min after a player’s most intense period and were partly restored in the subsequent 5-min period.Discussion:Possible explanations for the observed declines in activity profiles for the team and individual players include fatigue, situational factors, and pacing. However, underlying mechanisms were not accounted for, and these assumptions are therefore based on previous team-sport studies.

Background: Player tracking devices are commonly used to monitor external load from training and matches in team sports. Yet, how the derived external load variables relate to fatigue and recovery post-training or post-match is scarcely researched. The objective was, therefore, to investigate how external load variables affect recovery markers up to 72 h post-match. Methods: Semiprofessional players from six teams wore tracking devices during three experimental football matches. External load variables including individual playing duration, total distance, PlayerLoad™, high-intensity running, and high-intensity events were derived from the tracking devices, and blood samples and performance tests from 24–59 players were undertaken post-match. The effect of the external load variables on creatine kinase, myoglobin, and countermovement jump at 1, 24, 48, and 72 h, and 30-m sprint and Yo-Yo intermittent recovery tests level 1 at 72 h post-match, were modeled. Effects were gauged as two standard deviations of the external load and interpreted as the difference between a typical high-load and a typical low-load match. The effects were evaluated with 90% confidence intervals and magnitude-based inferences. Results: High-intensity running had very likely substantial effects on creatine kinase and myoglobin (moderate factor increases of 1.5–2.0 and 1.3–1.6 respectively), while duration, total distance, and HIE showed small, likely substantial effects. PlayerLoad™ and total distance had likely substantial effects on 30-m sprint time (small increases of 2.1–2.6%). Effects on countermovement jump performance were generally non-substantial. Despite these relationships, the uncertainty was too large to predict the recovery of individual players from the external load variables. Conclusions: This study provides evidence that external load variables have an effect on recovery markers up to 72 h post-match. Hence, tracking external load in matches may be helpful for practitioners when managing training load and recovery strategies post-match. However, it is recommended that several different external load variables are monitored. Future research should continue to address the problem of predicting recovery from external load variables.

The objectives of this study were to; quantify positional differences in the activity profiles of Gaelic football players and to evaluate decrements in physical performance during a pre-season competition. Global positioning system (GPS) data was recorded from 36 players from 3 teams across 5 games. The relative distance covered in locomotor activities, peak speed, relative PlayerLoad™ (PL.min -1 )and heart rate responses were evaluated between playing positions and across match periods using a mixed model analysis. The mean relative distance of 92.4 ± 23.3 m.min -1 covered,comprised 28.4 ± 10.2 m.min -1 of high intensity running (m.min -1 ≥4.0 m.s -1 ) and 9.9 ± 3.9 m.min -1 of very high intensity running (m.min -1 ≥5.5 m.s -1 ). High intensity running and relative PlayerLoad™ (PL.min -1 ) was significantly higher in half-backs, midfielders and half-forwards compared to the full-backs, whereas only the half-backs and half-forwards displayed significantly greater values compared to full-forwards. When compared to the first 15 min (P1) of the game, analysis of pooled positional data revealed significant declines in; overall relative distance covered, jogging (≥2.0 - < 4.0 m.s -1 ), running (≥4.0

Fast acceleration is an important performance factor in handball. In addition to traditional sprint training (TST), resisted-sprint training (RST) is a method often used to improve acceleration. However, studies on RST show conflicting results, and underlying mechanisms have not been studied.Purpose:To compare the effects of RST, by sled towing, against TST on sprint performance and muscle architecture.Methods:Participants (n = 18) were assigned to either RST or TST and completed 2 training sessions of RST or TST per week (10 wk), in addition to their normal team training. Sprint tests (10 and 30 m) and measurements of muscle architecture were performed pre- and posttraining.Results:Beneficial effects were found in the 30-m-sprint test for both groups (mean; ±90% CL: TST = −0.31; ±0.19 s, RST = −0.16; ±0.13 s), with unclear differences between the groups. Only TST had a beneficial effect on 10-m time (−0.04; ±0.04 s), with a likely difference between the 2 groups (85%, ES = 0.60). Both groups had a decrease in pennation angle (−6.0; ±3.3% for TST and −2.8; ±2.0% for RST), which had a nearly perfect correlation with percentage change in 10-m-sprint performance (r = .92). A small increase in fascicle length (5.3; ±3.9% and 4.0; ±2.1% for TST and RST, respectively) was found, with unclear differences between groups.Discussion:TST appears to be more effective than RST in enhancing 10-m-sprint time. Both groups showed similar effects in 30-m-sprint time. A similar, yet small, effect of sprint training on muscle architecture was observed in both groups.

To assess the reliability and sensitivity of commercially available inertial measurement units to measure physical activity in team handball.Twenty-two handball players were instrumented with 2 inertial measurement units (OptimEye S5; Catapult Sports, Melbourne, Australia) taped together. They participated in either a laboratory assessment (n = 10) consisting of 7 team handball-specific tasks or field assessment (n = 12) conducted in 12 training sessions. Variables, including PlayerLoad™ and inertial movement analysis (IMA) magnitude and counts, were extracted from the manufacturers' software. IMA counts were divided into intensity bands of low (1.5-2.5 m·sLaboratory assessment: IMA magnitude showed a good reliability (CV = 3.1%) in well-controlled tasks. CV increased (4.4-6.7%) in more-complex tasks. Field assessment: Total IMA counts (CV = 1.8% and SWD = 2.5%), PlayerLoad (CV = 0.9% and SWD = 2.1%), and their associated variables (CV = 0.4-1.7%) showed a good reliability, well below the SWD. However, the CV of IMA increased when categorized into intensity bands (2.9-5.6%).The reliability of IMA counts was good when data were displayed as total, high, or medium/high counts. A good reliability for PlayerLoad and associated variables was evident. The CV of the previously mentioned variables was well below the SWD, suggesting that OptimEye's inertial measurement unit and its software are sensitive for use in team handball.

Game-based training drills are popular in team sports. This study compared two game-based training conditions and official matches in team handball. Thirty-one women players wore inertial measurement units in five training sessions and five official matches. In training, 3vs3 and 6vs6 game-based training conditions were performed with a 5-min duration. PlayerLoad™ and high-intensity events (HIEs; >2.5 m · s−1) were extracted from the raw data. Data were analysed using magnitude-based inferences and reported with effect sizes (ESs). PlayerLoad™ · min−1 from all positions combined was 11.37 ± 0.49 (mean ± 90% confidence limits) and 9.71 ± 0.3 for the 3vs3 and 6vs6 conditions, respectively. Backs (ES: 1.63), wings (ES: 1.91), and pivots (ES: 1.58) had greater PlayerLoad™ in 3vs3 than 6vs6. Substantially greater HIE · min−1 in 3vs3 occurred for all positions. There was substantially greater PlayerLoad™ · min−1 in 3vs3 and 6vs6 than match play for backs, wings, and pivots. Wings (ES: 1.95), pivots (ES:...

Differences in performance between winning and losing were examined in 1 elite Gaelic football team in 20 games across 2 complete competitive seasons. Possession was codified using Dartfish TeamPro software and distance covered; walking, jogging, running, and running at high and maximum speeds, was evaluated using Catapult Optimeye S5 player tracking devices. Distance covered in low intensity activity (LIA, ˂4.0 m.s-1 ), high intensity running (HIR, ≥4.0 m·s-1 ) and very high intensity running (VHIR, ≥5.5 m·s-1 ) was also examined along with PlayerLoad™, which represented a composite of all accelerations. Data from 53 players (n=405 files) was collated into specific match periods to facilitate a temporal analysis between the first and second halves and from quarter 1 (Q1) to quarter 4 (Q4), with significance accepted at p ≤ 0.05. Total distance and running was higher in games lost, whereas total distance, walking and LIA was higher in halves lost. Only walking was higher in quarters lost. The percentage of possession declined in halves and quarters lost. In games lost, high speed running declined in the second half. From Q1 to Q4; PlayerLoad™, total distance, jogging, high speed running, HIR and VHIR, decreased in all games combined and in games lost. Possession frequency declined in Q4 in all games and in games won. Overall, total distance was higher in games lost and physical performance declines were more pronounced when examined by match quarter compared to half and were only apparent in games lost. Similarly, reductions in possession frequency and percentage were more evident when examined by quarter or period lost, respectively. These findings can inform the prescription of conditioning and field-training strategies to mitigate the reductions in performance observed in losing and towards the end of games.

Long-term effects of training are important information for athletes, coaches, and scientists when associating changes in physiological indices with changes in performance. Therefore, this study monitored changes in aerobic and anaerobic capacities and performance in a group of elite cross-country skiers during a full sport season. Thirteen men (age, 23 ± 2 years; height, 182 ± 6 cm; body mass, 76 ± 8 kg; V2 roller ski skating VO2max, 79.3 ± 4.4 ml·kg·min or 6.0 ± 0.5 L·min) were tested during the early, middle, and late preparation phase: June (T1), August (T2), and October (T3); during the competition phase: January/February (T4); and after early precompetition phase: June (T5). O2-cost during submaximal efforts, V[Combining Dot Above]O2peak, accumulated oxygen deficit (ΣO2-deficit), and performance during a 1,000-m test were determined in the V2 ski skating technique on a roller ski treadmill. Subjects performed their training on an individual basis, and detailed training logs were categorized into different intensity zones and exercise modes. Total training volume was highest during the summer months (early preseason) and decreased toward and through the winter season, whereas the volume of high-intensity training increased (all p < 0.05). There was a significant main effect among testing sessions for 1,000 m time, O2-cost, and ΣO2-deficit (Cohen's d effect size; ES = 0.63-1.37, moderate to large, all p < 0.05). In general, the changes occurred between T1 and T3 with minor changes in the competitive season (T3 to T4). No significant changes were found in V[Combining Dot Above]O2peak across the year (ES = 0.17, trivial). In conclusion, the training performed by elite cross-country skiers induced no significant changes in V[Combining Dot Above]O2peak but improved performance, O2-cost, and ΣO2-deficit.

Matt Spencer poster presentation for BD2K event 11/29/16.

Purpose:International women’s team handball is a physically demanding sport and is intermittent in nature. The aim of the study was to profile high-intensity events (HIEs) in international women’s team handball matches with regard to playing positions.Methods:Twenty female national-team handball players were equipped with inertial movement units (OptimEye S5, Catapult Sports, Australia) in 9 official international matches. Players were categorized in 4 different playing positions: backs, wings, pivots, and goalkeepers (GKs). PlayerLoad™, accelerations (Acc), changes of direction (CoD), decelerations (Dec), and the sum of the latter 3, HIEs, were extracted from raw-data files using the manufacturer’s software. All Acc, Dec, CoD, and HIEs >2.5 m/s were included. Data were log-transformed and differences were standardized for interpretation of magnitudes and reported with effect-size statistics.Results:Mean numbers of events were 0.7 ± 0.4 Acc/min, 2.3 ± 0.9 Dec/min, and 1.0 ± 0.4 CoD/min. Substantial differences between playing positions, ranging from small to very large, were found in the 3 parameters. Backs showed a most likely greater frequency for HIE/min (5.0 ± 1.1 HIE/min) than all other playing positions. Differences between playing positions were also apparent in PlayerLoad/min.Conclusion:HIEs in international women’s team handball are position specific, and the overall intensity depends on the positional role within a team. Specific HIE and intensity profiles from match play provide useful information for a better understanding of the overall game demands and for each playing position.

Variations in rates of growth and development in young football players can influence relationships among various fitness qualities.Purpose:To investigate the relationships between repeated-sprint ability and other fundamental fitness qualities of acceleration, agility, explosive leg power, and aerobic conditioning through the age groups of U1 1 to U18 in highly trained junior football players.Methods:Male players (n = 119) across the age groups completed a fitness assessment battery over two testing sessions. The first session consisted of countermovement jumps without and with arm swing, 15-m sprint run, 15-m agility run, and the 20-m Shuttle Run (U11 to U15) or the Yo-Yo Intermittent Recovery Test, Level 1 (U16 to U18). The players were tested for repeated-sprint ability in the second testing session using a protocol of 6 × 30-m sprints on 30 s with an active recovery.Results:The correlations of repeated-sprint ability with the assorted fitness tests varied considerably between the age groups, especially for agility (r = .02 to .92) and explosive leg power (r = .04 to .84). Correlations of repeated sprint ability with acceleration (r = .48 to .93) and aerobic conditioning (r = .28 to .68) were less variable with age.Conclusion:Repeated-sprint ability associates differently with other fundamental fitness tests throughout the teenage years in highly trained football players, although stabilization of these relationships occurs by the age of 18 y. Coaches in junior football should prescribe physical training accounting for variations in short-term disruptions or impairment of physical performance during this developmental period.

Ab initio protein secondary structure (SS) predictions are utilized to generate tertiary structure predictions, which are increasingly demanded due to the rapid discovery of proteins. Although recent developments have slightly exceeded previous methods of SS prediction, accuracy has stagnated around 80 percent and many wonder if prediction cannot be advanced beyond this ceiling. Disciplines that have traditionally employed neural networks are experimenting with novel deep learning techniques in attempts to stimulate progress. Since neural networks have historically played an important role in SS prediction, we wanted to determine whether deep learning could contribute to the advancement of this field as well. We developed an SS predictor that makes use of the position-specific scoring matrix generated by PSI-BLAST and deep learning network architectures, which we call DNSS. Graphical processing units and CUDA software optimize the deep network architecture and efficiently train the deep networks. Optimal parameters for the training process were determined, and a workflow comprising three separately trained deep networks was constructed in order to make refined predictions. This deep learning network approach was used to predict SS for a fully independent test dataset of 198 proteins, achieving a Q3 accuracy of 80.7 percent and a Sov accuracy of 74.2 percent.

Repeated-sprint ability is thought to be an important fitness component of team sports. However, little is known about the effect sport-specific training has on this fitness component. Therefore, the purpose of this study was to investigate the effects of field-hockey specific training on repeated-sprint ability, plasma hypoxanthine (Hx) concentration and other blood parameters in 18 elite female field-hockey players. All subjects performed a repeated-sprint ability test on a cycle ergometer (5 x 6-sec maximal sprints every 30 secs) before and after seven weeks of training, designed to improve repeated-sprint ability. Following training, there was a significant (P0.05) increase in absolute total work (20.73+/-2.00 to 21.15+/-2.07 kJ, mean+/-SD). However, there was no significant change in total work when expressed per kg of body mass (341.3+/-16.4 to 345.5+/-18.8 J x kg(-1)). In addition, training resulted in a significant (P0.05) decrease in change values (peak-rest values) for Hx (8.2+/-3.8 to 5.5+/-2.7 micromol x L(-1)) and hydrogen ion concentration (22.8+/-5.2 to 19.1+/-5.1 nmol x L(-1)). The significant increase in absolute total work following seven weeks of field-hockey specific training was most likely due to an increase in lean muscle mass. The significant decrease in plasma Hx concentration (post-test minus rest values) following seven weeks of field hockey-specific training provides evidence that Hx production and/or efflux from the muscle are reduced. Therefore, one adaptation of sport-specific repeated-sprint training may be to conserve the purine nucleotide pool.

The antifungal phenazines produced by certain root colonizing pseudomonads are credited with contributing to the biocontrol activity of these isolates. However, the phenazine producer Pseudomonas chlororaphis O6 also induces systemic resistance in tobacco. Protection against two foliar bacterial pathogens, the wild fire pathogen, Pseudomonas syringae pv. tabaci, and Erwinia carotovora subsp. carotovora that causes a soft rot, was observed. A mutation in the bacterial global regulator gacS gene eliminated certain secondary traits, including phenazine production, but did not prevent induction of resistance in tobacco to P. syringae pv. tabaci. However, induction of resistance to E. carotovora subsp. carotovora was impaired in plants colonized by the GacS mutant compared to the level of protection in plants colonized by wild-type P. chlororaphis O6. Colonization by both the wild-type and the GacS mutant caused increased accumulation for transcripts of plant defense genes regulated by ethylene. Tobacco transformed with a mutant etr1 gene to reduce ethylene sensitivity did not display induced resistance to E. carotovora when colonized by P. chlororaphis O6. We conclude that inducers other than phenazines appear to initiate the pathways for systemic resistance induced by P. chlororaphis O6. q 2003 Elsevier Ltd. All rights reserved.

The ability to maintain maximal power over a series of sprints may depend, in part, on the resynthesis of PCr and the buffering of hydrogen ions (H+). As a result, repeated-sprint ability may be related to VO2peak and changes in plasma pH. Fourteen elite female field-hockey players (Mean +/- SD body mass: 61.1 +/- 5.9 kg and VO2pea: 55.7 +/- 3.2 mL x kg(-1) x min(-1)) participated in this investigation. Tests consisted of a repeated-sprint ability test (5 x 6-s all-out sprints every 30 s) and a VO2peak test. Capillary and venous blood was sampled before and after the 5 x 6-s cycle test for the determination of lactate concentration and pH. There were no significant correlations between VO2peak (mL x kg(-1) x min(-1)) and total work (J.kg(-1); r = 0.35), or power decrement (r = 0.30) during the repeated-sprint ability test. There was, however, a significant correlation between power decrement and change in plasma [H+] (r = 0.66; P < 0.05). The results of this study show that in a homogenous group of elite, team-sport athletes, VO2peak (mL x kg(-1) x min(-1)) is not a strong predictor of repeated-sprint ability. However, in this group, there is a significant correlation between change in plasma [H+] and repeated-sprint ability.

It has previously been shown that the metabolic acidaemia induced by a continuous warm-up at the 'lactate threshold' is associated with a reduced accumulated oxygen deficit and decreased supramaximal performance. The aim of this study was to determine if an intermittent, high-intensity warm-up could increase oxygen uptake (VO2) without reducing the accumulated oxygen deficit, and thus improve supramaximal performance. Seven male 500 m kayak paddlers, who had represented their state, volunteered for this study. Each performed a graded exercise test to determine VO2max and threshold parameters. On subsequent days and in a random, counterbalanced order, the participants then performed a continuous or intermittent, high-intensity warm-up followed by a 2 min, all-out kayak ergometer test. The continuous warm-up consisted of 15 min of exercise at approximately 65% VO2max. The intermittent, high-intensity warm-up was similar, except that the last 5 min was replaced with five 10 s sprints at 200% VO2max, separated by 50 s of recovery at approximately 55% VO2max. Significantly greater (P0.05) peak power (intermittent vs continuous: 629 +/- 199 vs 601 +/- 204 W) and average power (intermittent vs continuous: 328 +/- 39.0 vs 321 +/- 42.4 W) were recorded after the intermittent warm-up. There was no significant difference between conditions for peak VO2, total VO2 or the accumulated oxygen deficit. The results of this study indicate that 2 min all-out kayak ergometer performance is significantly better after an intermittent rather than a continuous warm-up.

To study performance, physiological and biomechanical responses during repeated upper-body sprint exercise. Twelve male elite cross-country skiers performed eight 8-s maximal poling sprints with a 22-s recovery while sitting on a modified SkiErg poling ergometer. Force, movement velocity, cycle rate, work per cycle, oxygen saturation in working muscles and pulmonary oxygen uptake were measured continuously. A 3-min all-out ergometer poling test determined VO2peak, and 1 repetition maximum (1RM) strength was determined in a movement-specific pull-down. Average sprint power was 281 ± 48 W, with the highest power on the first sprint, a progressive decline in power output over the following four sprints, and a sprint decrement of 11.7 ± 4.1 %. Cycle rate remained unchanged, whereas work per cycle progressively decreased (P

Purpose: Performance improvements after caffeine (CAF) ingestion are well documented when using a 1-d protocol. In numerous competitions such as the Tour de France, Tour de Ski, world championships, and National College Athletic Association championships, athletes compete for several days in a row. To date, no studies have investigated the effects of CAF when competing for consecutive days in a row. This study aimed to investigate the effects of placebo (PLA) and two different CAF doses (3 and 4.5 mg·kg-1 body mass) on performance in a 10-min all-out, cross-country, double poling ergometer test (C-PT) 2 d in a row. Method: Eight highly trained male cross-country skiers (V·O2max-run, 78.5 ± 1.6 mL·kg-1·min-1) participated in the study, which was a randomized, double-blind, PLA-controlled, crossover design. Performance was assessed as distance covered during a 10-min all-out C-PT. Oral ingestion of CAF or PLA was consumed 75 min before the all-out C-PT. Results: Poling distance was improved after CAF ingestions compared with that after PLA on both days. The improvements on day 1 were 4.0% (90% confidence limits, ±3.3) and 4.0% ± 2.9% for both CAF doses, respectively (P < 0.05), whereas improvements on day 2 were 5.0% ± 3.6% and 5.1% ± 2.8% for CAF3 and CAF4.5, respectively, compared with those for PLA. Improved performance was associated with increased HR, adrenaline concentration, blood lactate concentration, and V·O2 consumption after CAF ingestion. Furthermore, performance was elevated despite higher creatine kinase concentration and muscular pain at arrival on day 2 for both CAF doses. Conclusions: Both CAF doses improved performance in the 10-min all-out C-PT compared with PLA over two consecutive days. Therefore, CAF seems useful for athletes competing over consecutive days despite higher muscle damage occurring after enhanced performance on the first day.

More and more 2D graphics engines are extended with GPU accelerated code paths to share the workload between the CPU and GPU. This becomes even more important on embedded systems which are resource constrained. In the following, we present the GL2D engine, which is optimized for GPUs with OpenGL ES 2.0 support.

Many team sports require participants to repeatedly produce maximal or near maximal sprints of short duration (1-7s) with brief recovery periods, over an extended period of time (60-90 min). Therefore, an important fitness component for these sports is what is often termed repeated sprint ability (RSA). A variety of tests have been devised to assess RSA. However, while the reliability of some of these tests has been reported, there has been no published attempt to assess the validity of RSA tests. The purpose of the present paper was to assess the validity of a popular RSA test--the 5 x 6 s cycle test. Ten moderately-trained males (Mean+/-SD age: 23.6+/-3.0 yrs, mass: 71.8+/-7.4 kg, peak VO2: 46.32+/-4.16 ml.kg(-1)min(-1)) participated in the investigation. Following familiarisation, subjects reported to the laboratory at the same time of day, on three occasions, each separated by at least 48 hours. Testing consisted of a 5 x 6 s cycle test (5 x 6 s maximal sprints every 30 s), a graded exercise test (GXT) and a simulated game (3 x 15 min periods separated by five min). The simulated game consisted of a 1-min circuit that was repeated 15 times in each period. The circuit replicated typical movement patterns observed during motion analysis of field hockey games. Each circuit commenced with a 15-m maximum sprint through timing gates. Time to run 5, 10 and 15 m was recorded. Oxygen consumption was measured during both the GXT and the simulated game with a portable gas analysis system (Cosmed K4 b2, Italy). Correlation coefficients between dependent variables were calculated using Pearson's Product Moment (r). There was a significant correlation between power decrement during the 5 x 6 s cycle test and decrement in 15-m time across the three periods (r = 0.76, P0.05), but not decrement in 10-m time (r = 0.54) or 5-m time (r = 0.42). These results suggest that the 5 x 6 s cycle test is valid for assessing the decrement in 15-m time, but not the decrement in 5 or 10m time. Thus, one measure of RSA (sprint decrement) appears to be specific to the test protocol, rather than a general quality. The most likely explanation is that the energy requirements of the 5 x 6 s cycle test more closely match those required to repeatedly run 15 m (mean time = 2.74 s) than to repeatedly run 10 m (mean time = 1.97 s) or 5 m (mean time = 1.13 s). It is therefore suggested that, while the 5 x 6 s cycle test is often used to assess RSA ability in a wide range of sports, it may need to be modified to reflect the common sprint distances found in specific sports.

Analyses of elite competitive performance provide useful information for research and practical applications.Purpose:Here the authors analyze performance times of cross-country skiers at international competitions (World Cup, World Championship, and Olympics) in classical and free styles of women’s and men’s distance and sprint events, each with a total of 410–569 athletes competing in 1–44 races at 15–25 venues from seasons 2002 to 2011.Methods:A linear mixed model of race times for each event provided estimates of within-athlete race-to-race variability expressed as a coefficient of variation (CV) after adjustment for fixed or random effects of snow conditions, altitude, race length, and competition terrain.Results:Within-athlete variability was similar for men and women over various events for all athletes (CV of 1.5–1.8%) and for the annual top-10 athletes (1.1–1.4%). Observed effects of snow conditions and altitude on mean time were substantial (~2%) but mostly unclear, owing to large effects of terrain (CV of 4–10% in top-10 analyses). Predictability of performance was extremely high for all athletes (intraclass correlations of .90–.96) but only trivial to poor for top-10 athletes (men .00–.03, women .03–.35).Conclusion:The race-to-race variability of top-ranked skiers is similar to that of other elite endurance athletes. Estimates of the smallest worthwhile performance enhancement (0.3× within-athlete variability) will help researchers and practitioners evaluate strategies affecting performance of elite skiers.

This study investigated the relationship between performance measures of the lower-limb and repeated shuttle-sprint ability (RSSA) in elite adolescent handball players. Twenty-two male handball players (age: 17.7 ± 0.3 years) participated in the study. Subjects underwent measurements of lower-limb maximal strength (1-RM half back squat), explosive power (force-velocity test), jumping ability (squat and counter-movement jumps), sprinting velocities over the first step (VS) and the first 5 m (V5) of a 15 m sprint, and Yo-Yo Intermittent Recovery Test, Level 1. The players were tested for RSSA using a protocol of 6 repetitions of maximal 2 × 15-m shuttle sprints with 180° turns (∼6 s) departing every 20 s. RSSA results were evaluated in three ways: best time in a single trial (RSSAbest), decrement (RSSAdec) and total time (RSSATT). The correlations of RSSA with the assorted fitness measures varied considerably. The RSSATT and RSSAdec were positively associated with 1-RM half back squat ( r = 0.78 and r = 0.68 respectively; pTT and RSSAbest and absolute peak power of the lower limb ( r = −0.81 and −0.66, respectively; pTT ( r = −0.71; p< 0.01). The RSSA test score has a moderate to large association with other explosive power measurements in elite adolescent handball players. RSSA may provide a useful composite index on responses to training or rehabilitation, and is very suitable for monitoring athletic performance of the lower-limbs of elite adolescent handball players.

One of the challenges for sports scientists working in football is to balance the needs for routine fitness testing with daily fatigue and well-being monitoring to best manage the physical preparation of players. In this commentary, the authors examine contemporary issues of fitness testing in football to identify ways of improving the value of routine testing and monitoring. A testing program must be well planned and organized to ensure that the results are useful. Different tests can be employed for younger and older players. A rigorous approach to analysis and interpretation of results is desirable, and database management must address both short- and long-term requirements of players, staff, and programs.

Purpose:To investigate performance and the associated physiological and biomechanical responses during upper-body repeated-sprint work.Methods:Twelve male ice sledge hockey players from the Norwegian national team performed eight 30-m sprints with start every 30 s and an active recovery between sprints. Time was captured every 10 m by photocells, cycle length and rate were determined by video analyses, and heart rate and blood lactate concentration were measured by conventional methods.Results:The percentage sprint decrement was 7% over the 8 trials, with significant reductions in performance from the previous trial already on the second trial (all P < .05). Furthermore, cycle rate was reduced by 9% over the 8 trials (P < .05). Similar changes in performance and kinematic patterns were evident for all 10-m phases of the sprints. Heart rate gradually increased to 94% of maximal (178 ± 10 beats/min) over the 8 trials, and the mean reduction in heart rate was 7 ± 2 beats/min during the 22–24 s of active recovery for all trials (all P < .05). The blood lactate concentration increased to the athletes’ maximal levels over the 8 sprints (P < .05).Conclusions:This is the first study to investigate performance, physiological, and biomechanical aspects of self-propelled upperbody repeated-sprint work. The observed sprint decrement over the 8 trials was associated with reductions in cycle rates and high physiological demands. However, no kinematic and physiological characteristics were significantly correlated to repeated-sprint ability or the sprint decrement.

Background:To the authors’ knowledge, no study has investigated the concurrent repeated, high-intensity (RHIA) and repeated-sprint activity (RSA) of intermittent team-sport competition.Purpose:In this study, they report on the RSA of elite women’s football competition. In addition, they describe the nature of RHIA (eg, striding and sprinting activities) that involve a high energy cost and are associated with short (ie, ≤20 s) recovery periods.Methods:Thirteen elite women soccer players underwent video-based time–motion analysis on 34 occasions during national and international standard matches. RSA and RHIA were defined as successive (ie, 2) sprints or striding and sprinting efforts that occurred with ≤20 s between efforts.Results:The number of RSA and RHIA bouts performed was similar between the first and second halves of matches. Sprinting and striding/sprinting durations tended to remain relatively stable irrespective of the number of efforts in an RSA or RHIA bout or the period of play. However, recovery duration between efforts increased in the second half, when a greater number of efforts were performed per bout.Conclusion:These findings suggest that first- to second-half reductions in RHIA and RSA do not occur in elite women’s soccer competition. However, players increase the amount of low-intensity recovery undertaken between RHIA and RSA efforts, most likely in an attempt to maintain RHIA and RSA performance. These findings emphasize the importance of RSA and RHIA to elite women’s soccer and highlight the importance of training this quality to prevent reductions in performance during competitive match play.

Long-term effects of training are important information for athletes, coaches, and scientists when associating changes in physiological indices with changes in performance. Therefore, this study monitored changes in aerobic and anaerobic capacities and performance in a group of elite cross-country skiers during a full sport season. Thirteen men (age, 23 ± 2 years; height, 182 ± 6 cm; body mass, 76 ± 8 kg; V2 roller ski skating VO2max, 79.3 ± 4.4 ml·kg·min or 6.0 ± 0.5 L·min) were tested during the early, middle, and late preparation phase: June (T1), August (T2), and October (T3); during the competition phase: January/February (T4); and after early precompetition phase: June (T5). O2-cost during submaximal efforts, V[Combining Dot Above]O2peak, accumulated oxygen deficit (ΣO2-deficit), and performance during a 1,000-m test were determined in the V2 ski skating technique on a roller ski treadmill. Subjects performed their training on an individual basis, and detailed training logs were categorized into different intensity zones and exercise modes. Total training volume was highest during the summer months (early preseason) and decreased toward and through the winter season, whereas the volume of high-intensity training increased (all p0.05). There was a significant main effect among testing sessions for 1,000 m time, O2-cost, and ΣO2-deficit (Cohen's d effect size; ES = 0.63-1.37, moderate to large, all p0.05). In general, the changes occurred between T1 and T3 with minor changes in the competitive season (T3 to T4). No significant changes were found in V[Combining Dot Above]O2peak across the year (ES = 0.17, trivial). In conclusion, the training performed by elite cross-country skiers induced no significant changes in V[Combining Dot Above]O2peak but improved performance, O2-cost, and ΣO2-deficit.

Purpose:Two studies involving 122 handball players were conducted to assess the reliability, usefulness, and validity of a repeated shuttle-sprint and jump ability (RSSJA) test. The test consisted of 6 × (2 × 12.5-m) sprints departing on 25 s, with a countermovement jump performed during recovery between sprints.Methods:For the reliability and usefulness study, 14 well-trained male handball players performed the RSSJA test 7 d apart. Reliability of the test variables was assessed by the typical error of measurement, expressed as a coefficient of variation (CV). The minimal changes likely to be “real” in sprint time and jump power were also calculated. For the validity study, players of seven teams (national to international levels, women and men) performed the RSSJA test.Results:CV values for best and mean sprint time were 1.0% (90% CL, 0.7 to 1.6) and 1.0% (90% CL, 0.7 to 1.4). CV values for best and mean jump peak power were 1.7% (90% CL, 1.2 to 2.7) and 1.5% (90% CL, 1.1 to 2.5). The percent sprint and jump decrements were less reliable, with CVs of 22.3% (90% CL, 15.7 to 38.3) and 34.8% (90% CL, 24.2 to 61.8). Minimal changes likely to be “real” for mean sprint time and jumping peak power were -2.6% and 4.8%. Qualitative analysis revealed that the majority of between-team differences were rated as “almost certain” (ie, 100% probability that the true differences were meaningful) for mean sprint and jump performances.Conclusion:The RSSJA test is reliable and valid to assess repeated explosive effort sequences in team sports such as handball. Test results are likely to be representative of gender and competition level; thus the test could be used to discriminate across playing standards and monitor fitness levels.

In this study, we investigated the age-related differences in repeated-sprint ability and blood lactate responses in 134 youth football players. Players from the development programme of a professional club were grouped according to their respective under-age team (U-11 to U-18). Following familiarization, the participants performed a repeated-sprint ability test [6 x 30-m sprints 30 s apart, with active recovery (2.0-2.2 m . s(-1)) between sprints]. The test variables were total time, percent sprint decrement, and post-test peak lactate concentration. Total time improved from the U-11 to U-15 age groups (range 33.15 +/- 1.84 vs. 27.25 +/- 0.82 s), whereas no further significant improvements were evident from U-15 to U-18. No significant differences in percent sprint decrement were reported among groups (range 4.0 +/- 1.0% to 5.5 +/- 2.1%). Post-test peak lactate increased from one age group to the next (range 7.3 +/- 1.8 to 12.6 +/- 1.6 mmol . l(-1)), but remained constant when adjusted for age-related difference in body mass. Peak lactate concentration was moderately correlated with sprint time (r = 0.70, P0.001). Our results suggest that performance in repeated-sprint ability improves during maturation of highly trained youth football players, although a plateau occurs from 15 years of age. In contrast to expectations based on previous suggestions, percent sprint decrement during repeated sprints did not deteriorate with age.

This study investigated the effects of a moderate (MI) and a low intensity (LI) active recovery (both compared to a passive recovery) on repeated-sprint performance and muscle metabolism. Nine, male, subjects performed three repeated-sprint cycle tests (6 x 4 s sprints, every 25 s) in a semi-randomized, counter-balanced order. Recovery after each sprint for the MI and LI trials, respectively, was 60 W (approximately 35% VO(2max)) and 20 W (approximately 20% VO(2max). Biopsies were taken from the vastus lateralis pre- and immediately post-test during the MI and LI trials to determine adenosine triphosphate (ATP), phosphocreatine (PCr) and lactate (MLa(-)) content. Compared to passive, significant reductions in peak power of 3.4-6.0% were recorded in the MI trial (4 of 6 sprints; P < 0.05) and reductions of 3.5-3.7% in the LI trial (2 of 6 sprints; P < 0.05), with no differences between the two active trials. No significant differences were evident in ATP, PCr and MLa(-) between the two active recovery trials. In summary, peak power indices during the repeated-sprint test were inferior in the MI and LI active recovery trials, compared to passive. The minimal differences in performance and muscle metabolites between the MI and LI trials suggest that any low-to-moderate level of muscle activation will attenuate the resynthesis of PCr and the recovery of power output during repeated short-sprint exercise.