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Purpose: To determine the influence the number of contact efforts during a single bout has on running intensity during game- based activities and assess relationships between physical qualities and distances covered in each game. Methods: Eighteen semiprofessional rugby league players (age 23.6 ± 2.8 y) competed in 3 off-side small-sided games (2 x 10-min halves) with a contact bout performed every 2 min. The rules of each game were identical except for the number of contact efforts performed in each bout. Players performed 1, 2, or 3 x 5-s wrestles in the single-, double-, and triple-contact game, respectively. The movement demands (including distance covered and intensity of exercise) in each game were monitored using global positioning system units. Bench-press and back-squat 1-repetition maximum and the 30-15 Intermittent Fitness Test (30--15IFT) assessed muscle strength and high-intensity-running ability, respectively. Results: There was little change in distance covered during the single- contact game (ES = -0.16 to -0.61), whereas there were larger reductions in the double- (ES = -0.52 to -0.81) and triple-contact (ES = -0.50 to -1.15) games. Significant relationships (P < .05) were observed between 30--15IFT and high-speed running during the single- (r = .72) and double- (r = .75), but not triple-contact (r = .20) game. Conclusions: There is little change in running intensity when only single contacts are performed each bout; however, when multiple contacts are performed, greater reductions in running intensity result. In addition, high-intensity-running ability is only associated with running performance when contact demands are low. [ABSTRACT FROM AUTHOR]

Purpose: This study investigated the satisfaction of elite female cyclists with their body weight (BW) in the context of race performance, the magnitude of BW manipulation, and the association of these variables with menstrual function. Methods: Female competitors in the Australian National Road Cycling Championships (n = 32) and the Oceania Championships (n = 5) completed a questionnaire to identify current BW, BW fluctuations, perceived ideal BW for performance, frequency of weight consciousness, weight-loss techniques used, and menstrual regularity. Results: All but 1 cyclist reported that female cyclists are “a weight-conscious population,” and 54% reported having a desire to change BW at least once weekly; 62% reported that their current BW was not ideal for performance. Their perceived ideal BW was (mean ± SD) 1.6 ± 1.6 kg (2.5% ± 2.5%) less than their current weight (P < .01), and 73% reported that their career-lowest BW was either “beneficial” or “extremely beneficial” for performance. 65% reported successfully reducing BW in the previous 12 months with a mean loss of 2.4 ± 1.0 kg (4.1% ± 1.9%). The most common weight-loss technique was reduced energy intake (76%). Five cyclists (14%) had been previously diagnosed as having an eating disorder by a physician. Of the 18 athletes not using a hormonal contraceptive, 11 reported menstrual dysfunction (oligomenorrhea or amenorrhea). Conclusion: Elite Australian female cyclists are a weight-conscious population who may not be satisfied with their BW leading into a major competition and in some cases are frequently weight conscious. [ABSTRACT FROM AUTHOR]

Some athletes avoid dairy in the meal consumed before exercise due to fears about gastrointestinal discomfort. Regular exclusion of dairy foods may unnecessarily reduce intake of high quality proteins and calcium with possible implications for body composition and bone health. This study compared the effects of meals that included (Dairy) or excluded (Control) dairy foods on gastric comfort and subsequent cycling performance. Well-trained female cyclists (n = 32; mean ± SD; 24.3 ± 4.1 y; VO2peak 57.1 ± 4.9 ml/kg/min) completed two trials (randomized cross-over design) in which they consumed a meal (2 g/kg carbohydrate and 54 kJ/kg) 2 hr before a 90-min cycle session (80 min at 60% maximal aerobic power followed by a 10-min time trial; TT). The dairy meal contained 3 servings of dairy foods providing ~1350 mg calcium. Gut comfort and palatability were measured using questionnaires. Performance was measured as maximum mean power during the TT (MMP10min). There was no statistical or clinical evidence of an effect of meal type on MMP10min with a mean difference (Dairy – Control) of 4 W (95% CI [–2, 9]). There was no evidence of an association between pretrial gut comfort and meal type (p = .15) or between gut comfort delta scores and meal type postmeal (p = .31), preexercise (p = .17) or postexercise (p = .80). There was no statistical or clinical evidence of a difference in palatability between meal types. In summary, substantial amounts of dairy foods can be included in meals consumed before strenuous cycling without impairing either gut comfort or performance. [ABSTRACT FROM AUTHOR]

The efficacy of high-intensity interval training (HIIT) to elicit physiological and performance adaptations in endurance athletes has been established in men and to a lesser extent in women. This study compared lactate threshold (LT2) and performance adaptations to HIIT between men and women. Nine male and eight female cyclists and triathletes completed trials to determine their LT2 and 40 km cycling performance before, and after 10 HIIT sessions. Each HIIT session consisted of 10 × 90 s at peak power output, separated by 60 s active recovery. Main effects showed that HIIT improved peak power output (p = 0.05; ES: 0.2); relative peak power output (W.kg−1; p = 0.04; ES: 0.3 and W.kg−0.32; p = 0.04; ES: 0.3); incremental time to fatigue (p = 0.01; ES: 0.4), time trial time (p < 0.001; ES: 0.7) and time trial power output (p < 0.001; ES: 0.7) equally in both sexes. Although LT2 power output explained 77% of the performance improvement in women, no variable explained the performance improvement in men, suggesting another mechanism(s) was involved. Although HIIT improved cycling performance in men and women, it might not be appropriate to evaluate the effectiveness of HIIT using the same variables for both sexes. [ABSTRACT FROM AUTHOR]

Purpose: Repeated sprinting incorporating tackles leads to greater reductions in sprint performance than repeated sprinting alone. However, the influence of physical contact on the running demands of game-based activities is unknown. The aim of this study was to determine whether the addition of physical contact altered pacing strategies during game-based activities. Methods: Twenty-three elite youth rugby league players were divided into 2 groups. Group 1 played the contact game on day 1 while group 2 played the noncontact game; 72 h later they played the alternate game. Each game consisted of offside touch on a 30 x 70-m field, played over two 8-min halves. Rules were identical between games except the contact game included a 10-s wrestle bout every 50 s. Microtechnology devices were used to analyze player movements. Results: There were greater average reductions during the contact game for distance (25%, 38 m/min, vs 10%, 20 m/min; effect size [ES] = 1 78 ± 1 02) and low-speed distance (21%, 24 m/min, vs 0%, 2 m/s; ES - 1.38 ± 1.02) compared with the noncontact game. There were similar reductions in high-speed running (41%, 18 m/min, vs 45%, 15 m/min; ES = 0.15 ± 0.95). Conclusions: The addition of contact to game-based activities causes players to reduce low-speed activity in an attempt to maintain high-intensity activities. Despite this, players were unable to maintain high-speed running while performing contact efforts. Improving a player’s ability to perform contact efforts while maintaining running performance should be a focus in rugby league training. [ABSTRACT FROM AUTHOR]

The second lactate threshold (LT2) has previously been associated with endurance performance; however, comparisons between sexes are lacking regarding its efficacy. The aim of this study was to compare LT2 between men and women, specifically regarding its (a) relationship with endurance performance and (b) capacity to establish training and competition intensities. Competitive male (mean ± SD: age, 27.7 ± 4.7 years; ...O2max, 59.7 ± 5.2 ml•kg•min-1; n = 10) and female (mean ± SD: age, 27.3 6 6.2 years; ...O2max, 54.5 ± 5.3 ml•kg•min-1; n = 12) cyclists and triathletes completed an incremental cycle trial to volitional fatigue (for determination of ...O2max and LT2 via the modified D-max method), a constant load (65%) exercise trial of 30 minutes at LT2 power output, and a 40-km cycle time trial. The LT2 significantly correlated with 40-km cycling performance in both men (r = -0.69 to -0.77; p < 0.01-0.05) and women (r = -0.63 to -0.75; p < 0.01-0.05). All men sustained LT2 power output for 30 minutes, compared with 82% of women. Despite LT2 reflecting a similar heart rate, ...O2, and [La-] to those elicited during a 40-km time trial in both men and women, power output at LT2 was 6% higher (p < 0.05) than mean time trial power output in women, with no significant difference in men. Based on these findings, sexspecific recommendations have been suggested in regard to the use of LT2 for establishing performance potential, prescribing endurance training intensities and setting 40-km performance intensity. [ABSTRACT FROM AUTHOR]

The aim of the current study was to investigate the effect of 180 mg of pseudoephedrine (PSE) on cycling time-trial (TT) performance. Six well-trained male cyclists and triathletes (age 33 ± 2 yr, mass 81 ± 8 kg, height 182.0 ± 6.7 cm, VO2max 56.8 ± 6.8 ml · kg-1 · min-1; M ± SD) underwent 2 performance trials in which they completed a 25-min variable-intensity (50-90% maximal aerobic power) warm-up, followed by a cycling TT in which they completed a fixed amount of work (7 kJ/kg body mass) in the shortest possible time. Sixty minutes before the start of exercise, they orally ingested 180 mg of PSE or a cornstarch placebo (PLA) in a randomized, crossover, double-blind manner. Venous blood was sampled immediately pre- and postexercise for the analysis of pH plus lactate, glucose, and norepinephrine (NE). PSE improved cycling TT performance by 5.1% (95% CI 0-10%) compared with PLA (28:58.9 ± 4:26.5 and 30:31.7 ± 4:36.7 min, respectively). There was a significant Treatment × Time interaction (p = .04) for NE, with NE increasing during the PSE trial only. Similarly, blood glucose also showed a trend (p = .06) for increased levels postexercise in the PSE trial. The ingestion of 180 mg of PSE 60 min before the onset of high-intensity exercise improved cycling TT performance in well-trained athletes. It is possible that changes in metabolism or an increase in central nervous system stimulation is responsible for the observed ergogenic effect of PSE. [ABSTRACT FROM AUTHOR]

The cells of two bacterial spacecraft contaminants, Escherichia coli and Serratia liquefaciens in liquid medium were evaluated for 7 days under low temperatures with increasing concentrations of three salts to gain insight into their growth and survival under simulated Mars conditions. The reduced survival and failure of E. coli cell density to increase under simulated Mars conditions indicated that E. coli might be able to survive but not grow in surficial soils of Mars.

The Crustacean communities are studied for 3 years in a set of extant ephemeral wetlands in Illinois to examine the effects of habitat fragmentation on the genetic structure of extant crustacean metapopulations. It is concluded that the conversion of former wet prairie to agriculture may have reduced the metapopulations and that the conservation programs can preserve much of the historical biodiversity of ephemeral wetlands.

Physical profile data from elite, sub-elite, regional, under 21s (U21), under 19s (U19) and under 17s (U17) (n = 845) players from a state netball association in Australia were analysed. Within season changes were examined for the elite and sub-elite players. Longitudinal changes were examined for the elite across four consecutive netball seasons. Elite were significantly older (24.3 ± 3.4years), taller (182.4 ± 7.2cm) and heavier (73.42 ± 6.95kg) than other playing levels (p < 0.001, ES 0.49–3.26) and had higher vertical jump (VJ) data compared to all groups (p < 0.001, ES 0.47–0.93). U17's were significantly faster than elite, sub-elite and U19 players over 5m (p < 0.05, ES 0.36–0.58) while elite were faster over 20m compared to all groups (p < 0.01, ES 0.45–0.72). Elite achieved a greater distance (1350.8m; p < 0.05, ES 0.32–0.50) in the Yo-YoIRT1 compared to the sub-elite, regional, U19 and U17. VJ height significantly increased from the 2014 (51.6 ± 4.8cm) to the 2017 season (59.6 ± 6.3cm) for the elite players (p < 0.01, ES 1.18). Yo-YoIRT1 test scores increased significantly between the pre-season and in-season phases (p < 0.05, ES 0.17). [ABSTRACT FROM AUTHOR]

Objectives: We examined: (1) relationships among sub-maximal heart rate (sub-maxHR) following 4 minutes of the Yo-Yo intermittent recovery test level 1 (IR1) and maximal-effort performance (distance covered at volitional exhaustion), (2) test re-test reliability of sub-maxHR, and (3) whether changes in maximal-effort Yo-Yo performance are related with changes in sub-maxHR in professional rugby league players. Methods: Yo-Yo IR1 performances of 32 players were assessed before and after 28.5 ± 6.8 days of pre-season training. Relationships between sub-maxHR and maximal-effort Yo-Yo performance, and changes in maximal-effort performance and sub-maxHR were compared. Results: Maximal-effort Yo-Yo IR1 performance and sub-maxHR correlated negatively (r = −0.73, CI −0.85 to −0.55, very large). Coefficient of variation (CV) of sub-maxHR was 2.4% (CI 2.0−3.3%), worthwhile changes of small (0.7 [CI 0.5−1.0%]), moderate (2.1 [CI 1.6−3.0%]) and large (4.3 [CI 3.3−6.1%]) were identified. Training-induced changes in sub-maxHR and Yo-Yo IR1 performance displayed a negative correlation (r = −0.57, CI −0.74 to −0.33, large). Conclusions: sub-maxHR has a very large negative relationship with maximal-effort Yo-Yo IR1 performance. Training-induced changes in sub-maxHR demonstrated a large negative relationship with changes in Yo-Yo IR1 performance. The CV and worthwhile changes can determine meaningful variations in sub-maxHR in professional rugby league players. [ABSTRACT FROM AUTHOR]

The aim of this brief study was to investigate the effects of repeated jump testing on performance over 2 consecutive days while considering the possibility of diurnal changes. Fourteenmale subjects and 14 recreationally active female subjects completed countermovement jump (CMJ) and squat jump (SJ) testing on 5 occasions (baseline [0,800], 5 minutes [0,820], 8 hours [1,600], 24 hours [0,800], and 32 hours [1,600]) over 32 hours. An additional rested baseline test was conducted on a separate day in the afternoon (1,600) to compare jump performance between morning and afternoon baseline values. Excluding small decreases in CMJ height at 24 hours (p50.292, Cliff's delta520.225) in male subjects and similar decreases in CMJ height at 5 minutes (p 5 0.034, Cliff's delta 5 20.245) in addition to SJ height:contraction time at 32 hours (p 5 0.126, Cliff's delta5 0.153) in female subjects, findings generally showed no changes in jump performance over multiple assessments. Squat jumpmetrics may have showed small improvements betweenmorning and afternoon baseline values inmale subjects (SJ height:contraction time [p50.030, Cliff's delta50.225]) and female subjects (SJ height [p50.013, Cliff's delta50.173] and SJ height:contraction time [p50.091, Cliff's delta50.163)]. As jump performance was largely unaffected by repeated jump testing, the present findings support the use ofmonitoring practices and research designs that require multiple jump assessments within acute periods (;32 hours). [ABSTRACT FROM AUTHOR]

The aim of this study was to examine responses at 3 and 27 hours after low-load jump squat (LL) and maximal isometric half-squat (ISO) priming stimuli. Fifteen resistance-trained males performed LL (4 3 3 at 20% 1 repetition maximum [1RM]), ISO (4 3 3 seconds), and control (CON) activities (standardized warm-up) in a randomized and counterbalanced order. Countermovement jump (CMJ) and isometric midthigh pull tests were conducted to assess performance changes after priming and CON activities. No clear changes in CMJ measures were found after priming activities compared with CON. However, small effect size improvements were found after priming stimuli completed on the same day. A 2.9% decrease in concentric phase duration (CI 5 0.3-5.9, p 5 0.333, Cliff's delta520.156) and a 9.1% increase in RSImod (CI 50.2-12.3, p50.151, Cliff's delta520.218) occurred at 3 hours after LL compared with CON. Braking phase duration (CI 5 0.8-10.6, p 5 0.333, Cliff's delta520.213) was 2.9% shorter at 3 hours after ISO compared with CON. No clear changes in isometric peak force occurred after priming activities compared with CON. Additionally, questionnaires were completed to assess perceptual state and perceived effectiveness of the priming stimulus to influence performance. An increase in the "effect of activity" was perceived at 3 hours after LL and ISO (p 5 0.013-0.044, Cliff's delta 5 0.578-0.6) and at 27 hours after ISO (p 5 0.99, Cliff's delta 5 0.173) compared with CON. An increase in "muscular heaviness" was also reported at 3 hours after ISO compared with CON (p 5 0.199, Cliff's delta 5 0.320). The collective findings suggest limited benefits over the day after LL and ISO priming stimuli. However, as there was substantial variation in individual responses, the relative nature of priming responses should be considered when prescribing similar strategies in practical environments. [ABSTRACT FROM AUTHOR]