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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]

Harrison, PW, Kelly, VG, Jenkins, DG, McGuigan, MR, Holmberg, PM, and James, LP. Does moderate-load priming activity influence maximal upper-body performance and perceptual state?. J Strength Cond Res 37(11): e581-e587, 2023--The results of previous research indicate that resistance exercise "priming" may improve strength-power measures within 48 hours after their completion. Although researchers have primarily examined performance responses after lower-body priming stimuli, investigations examining the effects of upper-body resistance priming exercises are presently limited. Therefore, the aim of this study was to examine upper-body pushing and pulling performance in addition to perceptual responses 3 and 27 hours after moderate-load (ML) upper-body resistance priming exercise. Fourteen resistance-trained men were assigned to complete ML priming (4 3 3 bench press and bench pull at 65% 1RM [repetition maximum]) and control (rest) protocols in a randomized and counterbalanced order. Peak velocity during the bench throw and bench pull tests involving different loads (25, 50, and 75% 1RM) showed no practical change at 3 and 27 hours after the priming session (p 5 0.216-0.99, Cliff's d520.041 to 0.225). Small effect size increases in perceptual measures ("physical feeling," "physical performance," "aggression" [p 5 0.400-0.553, Cliff's d 5 0.183-0.201], and "muscular heaviness" [p 5 0.178, Cliff's d 5 0.231]) were found at 3 hours postpriming. A moderate practical increase was observed in perceived "physical feeling" compared with control (p 5 0.385, Cliff's d 5 0.349) in addition to small effect size increases in perceived "physical performance" and "aggression" (Cliff's d50.243-0.290) at 27 hours after priming activities. These results indicate that upper-body strength-power changes within 27 hours after ML upper-body resistance exercise priming are not practically meaningful. [ABSTRACT FROM AUTHOR]

"Priming exercises" are gaining popularity as a precompetition strategy to improve subsequent performance. Although priming exercise has been shown to improve various neuromuscular performance measures within 48 hours, a number of studies have also found no change or significant decreases in performance following priming interventions. Inconsistencies in findings are likely due to the many different variables used in the research. In addition, evidence suggests that the potential performance response following a priming stimulus is likely to be influenced by individual characteristics. Therefore, the purpose of this review is to examine the available evidence and identify those variables that most strongly determine whether priming stimuli involving resistance and stretch-shortening cycle exercise tasks are likely to improve performance within 48 hours of that stimulus. In addition to making recommendations based on the evidence to date, directions for future research are also identified. [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]

Purpose: Oral contraceptive (OC) use reduces peak aerobic capacity (...O2peak); however, whether it also influences adaptations to training has yet to be determined. This study aimed to examine the influence of OC use on peak performance (peak power output [PPO]) and physiological adaptations (...O2peak and peak cardiac output [...peak]) after sprint interval training (SIT) in recreationally active women. Methods: Women taking an OC (n = 25) or experiencing natural regular menstrual cycles (MC; n = 16) completed an incremental exercise test to assess ...O2peak, PPO, and ...peak before, immediately after, and 4 wk after 12 sessions of SIT. The SIT consisted ten 1-min efforts at 100% to 120% PPO in a 1:2 work-rest ratio. Results: Though ...O2peak increased in both groups after SIT (both P < 0.001), the MC group showed greater improvement (OC, +8.5%; MC, +13.0%; P = 0.010). Similarly, ...peak increased in both groups, with greater improvement in the MC group (OC, +4.0%; MC, +16.1%; P = 0.013). PPO increased in both groups (OC, +13.1%; MC, +13.8%; NS). All parameters decreased 4 wk after SIT cessation, but remained elevated from pretraining levels; the OC group showed more sustained training effects in ...O2peak (OC, -4.0%; MC, -7.7%; P = 0.010). Conclusion: SIT improved peak exercise responses in recreationally active women. However, OC use dampened ...O2peak and ...peak adaptation. A follow-up period indicated that OC users had spared ...O2peak adaptations, suggesting that OC use may influence the time course of physiological training adaptations. Therefore, OC use should be verified, controlled for, and considered when interpreting physiological adaptations to exercise training in women. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study is to compare the integrated muscle protein synthesis (MPS) rates of masters and younger triathletes over three consecutive days of intense endurance training. Recovery of cycling performance, after muscle-damaging running, was also compared between groups. Methods: Five masters (age, 53 ± yr; ...O2max, 55.7 ± 6.9 mL⋅kg-1⋅min-1) and six younger (age, 27 ± 2 yr; ...O2max, 62.3 ± 1.5 kg-1⋅min-1) trained triathletes volunteered for the study. Baseline skeletal muscle and saliva were initially sampled, after which a 150-mL bolus of deuterium oxide (70%) was consumed. Participants then completed a 30-min downhill run; three 20-km cycling time trials (TT) were completed 10,24, and 48 h after the run. Saliva was collected each morning, and skeletal muscle was again sampled 72 h after the run; both were used for MPS analysis. Diet was controlled throughout the study. Results: Over 3 d, masters triathletes showed a significantly lower myofibrillar fractional synthetic rate (1.49% ± 0.12%-d-1) compared with the younger (1.70% ± 0.09%-d-1) triathletes (P = 0.009, d = 1.98). There was also a trend for masters triathletes to produce a slower cycle TT (-3.0%, d = 0.46) than younger triathletes (-1.4%, d = 0.29) at 10 h postrun in comparison with the baseline performance. The between-group comparison of change was moderate (d = 0.51), suggesting slower acute recovery among masters triathletes. Conclusions: The present data show lower MPS rates in well-trained masters triathletes over 3 d of training, and this likely contributes to poorer muscle protein repair and remodeling. Furthermore, acute recovery of cycle TT performance tended to be poorer in the masters triathletes. [ABSTRACT FROM AUTHOR]

The article discusses research which investigated how three contact efforts influence running performance of athletes during small-sided rugby league games. Topics explored include the recruitment and physical evaluation of study participants, the way repeated high-intensity effort (RHIE) can affect physical performance of athletes, and the statistical analyses of data gathered such as relative distance, low-speed activity, and moderate speed running.

The article evaluates repeated high-intensity exercise performance testing for training professional rugby league and rugby union players in Queensland, Australia. The reliability and sensitivity of the test was assessed with the correlation of test performance with sprint speed and intermittent running recovery measurements. Data was analyzed using statistical methods such as analysis of variance, repeated measures statistics, and descriptive statistics.

The article presents the results of a study which investigated the physiological and anthropometric characteristics of rugby league football players who were particularly skilled at tackling. An overview of related previous research is provided, along with details of the experimental protocol, which involved tackling drills and vertical jump tests.

The article presents a study which examines the tackling ability of junior elite and subelite rugby football players, focusing on relationships between tackling ability and specific anthropometric and physiological characteristics. The criteria used for assessing tackling proficiency is reviewed. Results suggest that acceleration and lower body muscular power are the most important variables when predicting tackling ability.

The article presents a study which examined the differences in skill and physiological demands of elite male rugby league players engaged in on-side and off-side games. Results suggest that the cognitive demands of on-side games are greater than those for off-side games, but the physiological and skill demands of off-side games are greater than those for on-side games.

The article presents the results of a study which investigated the relationship between training loads and rates of injury during the professional rugby league preseason. An overview of related previous research is provided, along with details of the research protocol. The early preseason was found to be correlated with a higher rate of player injuries.

The article presents a study on oxidative stress in half and full Ironman triathletes. The study examined and compared pre- and postrace markers of oxidative stress in ultra endurance athletes training for a competion. The half Ironman triathletes had significantly higher erythrocytes glutathione peroxidase (GPX) activity at rest whereas the Ironman triathletes had significantly lower resting plasma malondialdehyde and significantly greater resting activities of GPX and catalese compared with controls.

The purpose of the present study was to examine the influence of 3 different high-intensity interval training regimens on the first and second ventilatory thresholds (VT1 and VT2), anaerobic capacity (ANC), and plasma volume (PV) in well-trained endurance cyclists. Before and after 2 and 4 weeks of training, 38 well-trained cyclists (VO2peak = 64.5 ± 5.2 ml·kg-1·min-1) performed (a) a progressive cycle test to measure VO2peak, peak power output (PPO), VT1, and VT2; (b) a time to exhaustion test (Tmax) at their VO2peak power output (Pmax); and (c) a 40-km time-trial (TT40). Subjects were assigned to 1 of 4 training groups (group 1: n = 8, 8 3 60% Tmax at Pmax, 1:2 work-recovery ratio; group 2: n = 9, 8 × 60% Tmax at Pmax, recovery at 65% maximum heart rate; group 3: n = 10, 12 × 30 seconds at 175% PPO, 4.5-minute recovery; control group: n = 11). The TT40 performance, VO2peak, VT1,VT2, and ANC were all significantly increased in groups 1, 2, and 3 (p < 0.05) but not in the control group. However, PV did not change in response to the 4-week training program. Changes in TT40 performance were modestly related to the changes in VO2peak, VT1, VT2, and ANC (r = 0.41, 0.34, 0.42, and 0.40, respectively; all p < 0.05). In conclusion, the improvements in TT40 performance were related to significant increases in VO2peak, VT1,VT2, and ANC but were not accompanied by significant changes in PV. Thus, peripheral adaptations rather than central adaptations are likely responsible for the improved performances witnessed in well-trained endurance athletes following various forms of high-intensity interval training programs. [ABSTRACT FROM AUTHOR]

Purpose: To determine whether a dose-response relationship exists between caffeine and 2000-m rowing performance., Methods: In this randomized, placebo-controlled, double-blind crossover study, 10 competitive male rowers (mean +/- SD: age = 20.6 +/- 1.4 yr, body mass = 87.7 +/- 10.5 kg, height = 186.8 +/- 6.8 cm, (.)VO2peak = 5.1 +/- 0.6 L x min(-1)) consumed 2, 4, or 6 mg x kg(-1) caffeine or a placebo 60 min before completing a 2000-m time trial on a rowing ergometer. The trials were preceded by a 24-h standardized diet (including a light preexercise meal of 2 g x kg(-1) CHO), and subjects were tested preexercise for hydration, caffeine abstinence, and blood glucose concentrations., Results: Time trial performance was not significantly different across the three caffeine doses or placebo (P = 0.249). After the three caffeine trials, postexercise plasma glucose and lactate concentrations were higher compared with the placebo trial (P < 0.05). Plasma caffeine concentrations after 60 min of ingestion were lower than the values reported previously by others following the same dose, and there was considerable interindividual variation in plasma caffeine concentrations in response to the various caffeine doses., Conclusions: The large interindividual response to the caffeine doses suggests that individual characteristics need to be considered when administering caffeine for performance enhancement. In addition, preexercise feeding may significantly affect plasma caffeine concentrations and the potential for caffeine to improve performance.

Purpose: The purpose of this study was to examine the influence of three different high-intensity interval training (HIT) regimens on endurance performance in highly trained endurance athletes., Methods: Before, and after 2 and 4 wk of training, 38 cyclists and triathletes (mean +/- SD; age = 25 +/- 6 yr; mass = 75 +/- 7 kg; VO(2peak) = 64.5 +/- 5.2 mL x kg(-1) min(-1)) performed: 1) a progressive cycle test to measure peak oxygen consumption (VO(2peak)) and peak aerobic power output (PPO), 2) a time to exhaustion test (T(max)) at their VO(2peak) power output (P(max)), as well as 3) a 40-km time-trial (TT(40)). Subjects were matched and assigned to one of four training groups (G(2), N = 8, 8 x 60% T(max) at P(max), 1:2 work:recovery ratio; G(2), N = 9, 8 x 60% T(max) at P(max), recovery at 65% HR(max); G(3), N = 10, 12 x 30 s at 175% PPO, 4.5-min recovery; G(CON), N = 11). In addition to G(1), G(2), and G(3) performing HIT twice per week, all athletes maintained their regular low-intensity training throughout the experimental period., Results: All HIT groups improved TT(40) performance (+4.4 to +5.8%) and PPO (+3.0 to +6.2%) significantly more than G(CON) (-0.9 to +1.1%; P < 0.05). Furthermore, G(1) (+5.4%) and G(2) (+8.1%) improved their VO(2peak) significantly more than G(CON) (+1.0%; P < 0.05)., Conclusion: The present study has shown that when HIT incorporates P(max) as the interval intensity and 60% of T(max) as the interval duration, already highly trained cyclists can significantly improve their 40-km time trial performance. Moreover, the present data confirm prior research, in that repeated supramaximal HIT can significantly improve 40-km time trial performance.