bluuebunny/crossref_metadata_2025_split huggingface dataset:
Caffeine Does Not Augment Markers of Muscle Damage or Leukocytosis Following Resistance Exercise
Authors: Machado Marco , Koch Alexander J. , Willardson Jeffrey M. , dos Santos Frederico C. , Curty Victor M. , Pereira Lucas N. 
Published: August 2016

Purpose:The purpose of this study was to evaluate the effects of caffeine ingestion before a resistance exercise session on markers of muscle damage (CK, LDH, ALT, AST) and leukocyte levels.Methods:Fifteen soccer athletes completed two resistance exercise sessions that differed only in the ingestion of caffeine or a placebo preworkout.Results:CK concentration increased significantly following the caffeine session (415.8 ± 62.8 to 542.0 ± 73.5) and the placebo session (411.5 ± 43.3 to 545.8 ± 59.9), with no significant differences between sessions. Similarly, LDH concentration increased significantly following the caffeine session (377.5 ± 18.0 to 580.5 ± 36.1) and the placebo session (384.8 ± 13.9 to 570.4 ± 36.1), with no significant differences between sessions. Both sessions resulted in significant increases in the total leukocyte count (caffeine = 6.24 ± 2.08 to 8.84 ± 3.41; placebo = 6.36 ± 2.34 to 8.77 ± 3.20), neutrophils (caffeine = 3.37 ± 0.13 to 5.15 ± 0.28; placebo = 3.46 ± 0.17 to 5.12 ± 0.24), lymphocytes (caffeine = 2.19 ± 0.091 to 2.78 ± 0.10; placebo = 2.17 ± 0.100 to 2.75 ± 0.11), and monocytes (caffeine = 0.53 ± 0.02 to 0.72 ± 0.06; placebo = 0.56 ± 0.03 to 0.69 ± 0.04), with no significant differences between sessions.Conclusion:Ingestion of caffeine at 4.5 mg⋅kg-1 did not augment markers of muscle damage or leukocyte levels above that which occurs through resistance exercise alone.
The Effect of Prior Endurance Training on Nap Sleep Patterns
Authors: Davies Daniel J. , Graham Kenneth S. , Chow Chin Moi 
Published: August 2016

Purpose:The use of daytime napping as a recovery tool following exercise is virtually unexplored. The objective of this study was to assess the quality of daytime nap sleep following endurance training in an athletic population, and to appraise the optimal circadian timing of the nap and the time interval between training and the nap.Methods:Six physically trained male subjects (22.5 ± 2.4 y) performed four separate standardized 90-min endurance training sessions followed by a 90-min daytime nap either 1 or 2 h after training (time interval), commencing at either 10:30 or 11:30 (circadian timing). During the nap, sleep was monitored using polysomnography. Subjective measurements of sleep quality, alertness and preparedness to train following a nap were recorded using a visual analog scale.Results:The duration of slow wave sleep (SWS) was significantly greater during the 11:30 naps (13.7 ± 9.0 min) compared with the 10:30 naps (6.9 ± 8.8 min) (P = .049). There was no significant difference in SWS duration between a 1-h (10.6 ± 10.2 min) or 2-h (10.0 ± 9.0 min) time interval between training and the nap (P = .82). No other sleep variables differed significantly according to circadian timing or time interval.Conclusion:Recovery naps commenced later in the morning contain more SWS than earlier naps. The data imply that daytime naps have a potential role as a valuable recovery tool following endurance exercise, given the suggested energy restorative functions of SWS.
Effects of the Playing Surface on Plantar Pressures During the First Serve in Tennis
Authors: Girard O. , Micallef J.-P. , Millet G.P. 
Published: August 2016

Purpose:This study aimed at examining the influence of different playing surfaces on in-shoe loading patterns in each foot (back and front) separately during the first serve in tennis.Methods:Ten competitive tennis players completed randomly five frst (ie, fat) serves on two different playing surfaces: clay vs GreenSet. Maximum and mean force, peak and mean pressure, mean area, contact area and relative load were recorded by Pedar insoles divided into 9 areas for analysis.Results:Mean pressure was significantly lower (123 ± 30 vs 98 ± 26 kPa; -18.5%; P < .05) on clay than on GreenSet when examining the entire back foot. GreenSet induced higher mean pressures under the medial forefoot, lateral forefoot and hallux of the back foot (+9.9%, +3.5% and +15.9%, respectively; both P < .01) in conjunction with a trend toward higher maximal forces in the back hallux (+15.1%, P = .08). Peak pressures recorded under the central and lateral forefoot (+21.8% and +25.1%; P < .05) of the front foot but also the mean area values measured on the back medial and lateral midfoot were higher (P < .05) on clay. No significant interaction between foot region and playing surface on relative load was found.Conclusions:It is suggested that in-shoe loading parameters characterizing the first serve in tennis are adjusted according to the ground type surface. A lesser asymmetry in peak (P < .01) and mean (P < .001) pressures between the two feet was found on clay, suggesting a greater need for stability on this surface.
Effects of a New Evaporative Cooling Solution During Rowing in a Warm Environment
Authors: Mujika Iñigo , De Txabarri Rafa González , Pyne David 
Published: August 2016

Energicer is a new solution which purportedly increases evaporative cooling during exercise in the heat.Purpose:To evaluate the effect of Energicer on performance during indoor rowing in a warm environment.Methods:Eighteen highly trained rowers (age 23.3 ± 6.7 y, height 181.3 ± 6.0 cm, mass 76.7 ± 5.0 kg, peak aerobic power (PAP) 322.1 ± 24.3 W; mean ± SD) performed two indoor rowing trials at 25.0°C and 65.0% relative humidity. Each trial consisted of 10 min at 55% PAP, 5 min of rest, 10 min at 70% PAP, 10 min of rest, and 2000 m time trial. Subjects were randomly assigned to an experimental (COOL) or a placebo (PLA) condition, using a double-blind, crossover design. During COOL, subjects wore sweatbands soaked in Energicer on both forearms; during PLA, they wore identical sweatbands soaked in cool water. Physiological measures and rowing performance were analyzed in a post-test-only crossover design. Magnitude of the difference between treatments was interpreted using the Cohen’s effect statistic.Results:No substantial differences were observed in heart rate, blood lactate and RPE between treatments during the submaximal row (COOL 163 ± 10 bpm, 4.3 ± 1.0 mM, 14.5 ± 1.8; PLA 165 ± 11 bpm, 4.8 ± 1.4 mM, 14.6 ± 1.6) and the time trial (COOL 179 ± 9 bpm, 10.7 ± 2.3 mM, 20 ± 0; PLA 179 ± 10 bpm, 11.1 ± 2.2 mM, 20 ± 0). Time (419 ± 11 vs 420 ± 12 s), mean power (305 ± 24 vs 304 ± 26 W), sweat loss (1013 ± 186 vs 981 ± 161 mL) and pacing strategy during the time trial were similar in COOL and PLA. The magnitude of differences between treatments was trivial for all measured variables.Conclusion:Energicer failed to provide a substantial benefit during indoor rowing in a warm environment. Whether Energicer is beneficial during more prolonged exercise and/or under more stressful environmental conditions remains to be elucidated.
An Attempt to Quantify the Placebo Effect From a Three-Week Simulated Altitude Training Camp in Elite Race Walkers
Authors: Saunders Philo U. , Ahlgrim Christoph , Vallance Brent , Green Daniel J. , Robertson Eileen Y. , Clark Sally A. , Schumacher Yorck O. , Gore Christopher J. 
Published: August 2016

Purpose:To quantify physiological and performance effects of hypoxic exposure, a training camp, the placebo effect, and a combination of these factors.Methods:Elite Australian and International race walkers (n= 17) were recruited, including men and women. Three groups were assigned: 1) Live High:Train Low (LHTL,n= 6) of 14 h/d at 3000 m simulated altitude; 2) Placebo (n= 6) of 14 h/d of normoxic exposure (600 m); and 3) Nocebo (n= 5) living in normoxia. All groups undertook similar training during the intervention. Physiological and performance measures included 10-min maximal treadmill distance, peak oxygen uptake (VO2peak), walking economy, and hemoglobin mass (Hbmass).Results:Blinding failed, so the Placebo group was a second control group aware of the treatment. All three groups improved treadmill performance by approx. 4%. Compared with Placebo, LHTL increased Hbmassby 8.6% (90% CI: 3.5 to 14.0%;P= .01, very likely), VO2peak by 2.7% (-2.2 to 7.9%;P= .34, possibly), but had no additional improvement in treadmill distance (-0.8%, -4.6 to 3.8%;P= .75, unlikely) or economy (-8.2%, -24.1 to 5.7%;P= .31, unlikely). Compared with Nocebo, LHTL increased Hbmassby 5.5% (2.5 to 8.7%;P= .01, very likely), VO2peak by 5.8% (2.3 to 9.4%;P= .02, very likely), but had no additional improvement in treadmill distance (0.3%, -1.9 to 2.5%;P= .75, possibly) and had a decrease in walking economy (-16.5%, -30.5 to 3.9%;P= .04, very likely).Conclusion:Overall, 3-wk LHTL simulated altitude training for 14 h/d increased Hbmassand VO2peak, but the improvement in treadmill performance was not greater than the training camp effect.
The Match Demands of Australian Rules Football Umpires in a State-Base Competition
Authors: Elsworthy Nathan , Dascombe Ben J. 
Published: August 2016

Purpose:The main purpose of the present study was to quantify the match running demands and physiological intensities of AF field and boundary umpires during match play.Methods:Thirty-five AF umpires [20 field (age: 24.7 ± 7.7 y, body mass: 74.3 ± 7.1 kg, Σ7 skinfolds: 67.8 ± 18.8 mm); 15 boundary (age: 29.6 ± 13.6 y, body mass: 71.9 ± 3.1 kg, Σ7 skinfolds: 65.6 ± 8.8 mm)] volunteered to participate in the study. Movement characteristics [total distance (TD), average running speed, high-intensity activity (HIA; >14.4 km·h–1) distance] and physiological measures [heart rate, blood lactate concentration ([BLa–]), and rating of perceived exertion] were collected during 20 state-based AF matches.Results:The mean (± SD) TD covered by field umpires was 11,492 ± 1,729 m, with boundary umpires covering 15,061 ± 1,749 m. The average running speed in field umpires was 103 ± 14 m·min-1, and was 134 ± 14 m·min-1 in boundary umpires. Field and boundary umpires covered 3,095 ± 752 m and 5,875 ± 1,590 m, during HIA, respectively. In the first quarter, HIA distance (field: P = .004, η2 = 0.071, boundary: P < .001, η2 = 0.180) and average running speed (field: P = .002, η2 = 0.078, boundary: P < .001, η2 = 0.191) were significantly greater than in subsequent quarters.Conclusions:The results demonstrate that both AF field and boundary umpires complete similar running demands to elite AF players and are subject to physical fatigue. Further research is warranted to see if this physical fatigue impacts on the cognitive function of AF umpires during match play.
Toe and Earlobe Capillary Blood Sampling for Lactate Threshold Determination in Rowing
Authors: Forsyth Jacky J. , Mann Chris , Felix James 
Published: August 2016

Purpose:In rowing ergometry, blood for determining lactate concentration can be removed from the toe tip without the rower having to stop. The purpose of the study was to examine whether sampling blood from the toe versus the earlobe would affect lactate threshold (Tlac) determination.Methods:Ten physically active males (mean ± age 21.2 ± 2.3 y; stature 179.2 ± 7.5 cm; body mass 81.7 ± 12.7 kg) completed a multistage, 3 min incremental protocol on the Concept II rowing ergometer. Blood was sampled simultaneously from the toe tip and earlobe between stages. Three different methods were used to determine Tlac.Results:There were wider variations due to the method of Tlac determination than due to the sample site; for example, ANOVA results for power output were F(1.25, 11.25) = 11.385, P = .004 for method and F(1, 9) = 0.633, P = .45 for site. The greatest differences in Tlac due to sample site in rowing occurred when Tlac was determined using an increase in blood lactate concentration by >1 mmol/L from baseline (TlacΔ1).Conclusions:The toe tip can be used as a suitable sample site for blood collection during rowing ergometry, but caution is needed when using the earlobe and toe tip interchangeably to prescribe training intensities based on Tlac, especially when using TlacΔ1 or at lower concentrations of lactate.
Tissue Oxygenation in Men and Women During Repeated-Sprint Exercise
Authors: Smith Kurt J. , Billaut François 
Published: August 2016

Purpose:To understand the role of O2 utilization in the sex differences of fatigue during intermittent activity, we compared the cerebral (prefrontal lobe) and muscle (vastus lateralis) oxygenation of men and women during repeated-sprint exercise (RSE).Methods:Ten men and 10 women matched for initial-sprint mechanical work performed ten, 10 s cycle sprints (with 30 s of rest) under normoxic (NM: 21% FIO2) and acute hypoxic (HY: 13% FIO2) conditions in a randomized single-blind and crossover design. Mechanical work was calculated and arterial O2 saturation (SpO2) was estimated via pulse oximetry during every sprint. Cerebral and muscle oxy- (O2Hb) and deoxy-hemoglobin (HHb) were monitored continuously by near-infrared spectroscopy.Results:Compared with NM, work decrement was accentuated (P = 0.01) in HY for both men (–16.4 ± 10.3%) and women (–16.8 ± 9.0%). This was associated with lower SpO2 and lower cerebral Δ[O2Hb] in both sexes (–13.6 ± 7.5%, P = .008, and –134.5 ± 73.8%, P = .003, respectively). These HY-induced changes were nearly identical in these men and women matched for initial-sprint work. Muscle Δ[HHb] increased 9-fold (P = .009) and 5-fold (P = .02) in men and women, respectively, and plateaued. This muscle deoxygenation was not exacerbated in HY.Conclusions:Results indicate that men and women matched for initial-sprint work experience similar levels of fatigue and systemic, cerebral, and peripheral adjustments during RSE performed in NM and HY. These data suggest that cerebral deoxygenation imposes a limitation to repeated-sprint performance.
Physiological Versus Psychological Evaluation in Taekwondo Elite Athletes
Authors: Casolino Erika , Cortis Cristina , Lupo Corrado , Chiodo Salvatore , Minganti Carlo , Capranica Laura 
Published: August 2016

Purpose:To anticipate outstanding athletic outcomes, the selection process of elite athletes simultaneously considers psychophysiological and technical parameters. This study aimed to investigate whether selected and nonselected athletes for the Italian national taekwondo team could be discriminated by means of sportspecific performances and psychophysiological responses to training.Participants:5 established Italian national athletes and 20 elite Italian taekwondo black belt athletes (9 women, 16 men; age 23.0 ± 3.1 y; body mass 67.0 ± 12.1 kg).Methods:To update the Italian national-team roster, the 20 elite athletes participated in a 1-wk selection camp (7 training sessions). Selected athletes (n = 10) joined established national athletes during the following 3-wk national training period (7 training sessions/wk). During the 1-wk selection camp, differences (P < .05) between selected and nonselected athletes in performances, heart-rate responses, blood lactate accumulation [La], subjective ratings of perceived exertion (session RPE), and mood were examined. During the 3-wk national training period, differences (P < .05) in mood between selected and established national athletes were investigated.Results:With respect to nonselected athletes, selected athletes responded better to training in terms of session RPE (P = .047) and [La] (P = .046). No difference in performance and mood between subgroups emerged. After the 3-wk national training period, differences (P = .035) emerged for confusion, with decreases in the established national athletes and increases for recently selected athletes.Conclusions:Session RPE and [La] seem to be more effective than psychological measures in discriminating between elite taekwondo athletes. Evaluation of mood could be effective in monitoring athletes’ response to national training.
Effects of Water Immersion on Posttraining Recovery in Australian Footballers
Authors: Elias George P. , Varley Matthew C. , Wyckelsma Victoria L. , McKenna Michael J. , Minahan Clare L. , Aughey Robert J. 
Published: August 2016

Purpose:The authors investigated the efficacy of a single exposure to 14 min of cold-water immersion (COLD) and contrast water therapy (CWT) on posttraining recovery in Australian football (AF).Method:Fourteen AF players participated in 3 wk of standardized training. After week 1 training, all players completed a passive recovery (PAS). During week 2, COLD or CWT was randomly assigned. Players undertook the opposing intervention in week 3. Repeat-sprint ability (6 × 20 m), countermovement and squat jumps, perceived muscle soreness, and fatigue were measured pretraining and over 48 h posttraining.Results:Immediately posttraining, groups exhibited similar performance and psychometric declines. At 24 h, repeat-sprint time had deteriorated by 4.1% for PAS and 1.0% for CWT but was fully restored by COLD (0.0%). At 24 and 48 h, both COLD and CWT attenuated changes in mean muscle soreness, with COLD (0.6 ± 0.6 and 0.0 ± 0.4) more effective than CWT (1.9 ± 0.7 and 1.0 ± 0.7) and PAS having minimal effect (5.5 ± 0.6 and 4.0 ± 0.5). Similarly, after 24 and 48 h, COLD and CWT both effectively reduced changes in perceived fatigue, with COLD (0.6 ± 0.6 and 0.0 ± 0.6) being more successful than CWT (0.8 ± 0.6 and 0.7 ± 0.6) and PAS having the smallest effect (2.2 ± 0.8 and 2.4 ± 0.6).Conclusions:AF training can result in prolonged physical and psychometric deficits persisting for up to 48 h. For restoring physical-performance and psychometric measures, COLD was more effective than CWT, with PAS being the least effective. Based on these results the authors recommend that 14 min of COLD be used after AF training.
Electrostimulation’s Enhancement of Recovery During a Rugby Preseason
Authors: Beaven C. Martyn , Cook Christian , Gray David , Downes Paul , Murphy Ian , Drawer Scott , Ingram John R. , Kilduff Liam P. , Gill Nicholas 
Published: August 2016

Rugby preseason training involves high-volume strength and conditioning training, necessitating effective management of the recovery-stress state to avoid overtraining and maximize adaptive gains.Purpose:Compression garments and an electrostimulation device have been proposed to improve recovery by increasing venous blood flow. These devices were assessed using salivary testosterone and cortisol, plasma creatine kinase, and player questionnaires to determine sleep quality, energy level, mood, and enthusiasm.Methods:Twenty-five professional rugby players were assigned to 1 of 2 treatments (compression garment or a concurrent combination of electrostimulation and compression) in a crossover design over 2 × 2-wk training blocks.Results:Substantial benefits were observed in self-assessed energy levels (effect size [ES] 0.86), and enthusiasm (ES 0.80) as a result of the combined treatment when compared with compression-garment use. The combination treatment had no discernable effect on salivary hormones, with no treatment effect observed. The electrostimulation device did tend to accelerate the return of creatine kinase to baseline levels after 2 preseason rugby games when compared with the compression-garment intervention (ES 0.61; P = .08).Conclusions:Electrostimulation elicited psychometric and physiological benefits reflective of an improved recovery-stress state in professional male rugby players when combined with a lower-body compression garment.
Comparison of Step-Wise and Ramp-Wise Incremental Rowing Exercise Tests and 2000-m Rowing Ergometer Performance
Authors: Ingham Stephen A. , Pringle Jamie S. , Hardman Sarah L. , Fudge Barry W. , Richmond Victoria L. 
Published: August 2016

Purpose:This study examined parameters derived from both an incremental step-wise and a ramp-wise graded rowing exercise test in relation to rowing performance.Methods:Discontinuous step-wise incremental rowing to exhaustion established lactate threshold (LT), maximum oxygen consumption (VO2maxSTEP), and power associated with VO2max (W VO2max). A further continuous ramp-wise test was undertaken to derive ventilatory threshold (VT), maximum oxygen consumption (VO2maxRAMP), and maximum minute power (MMW). Results were compared with maximal 2000-m ergometer time-trial power.Results:The strongest correlation with 2000-m power was observed for MMW (r = .98, P < .001), followed by W VO2max (r = .96; P < .001). The difference between MMW and W VO2max compared with the mean of MMW/W VO2max showed a widening bias with a greater difference coincident with greater power. However, this bias was reduced when expressed as a ratio term and when a baseline VO2 was accounted for. There were no differences (P = .85) between measures of VO2maxSTEP and VO2maxRAMP; rather, the measures showed strong association (r = .97, P < .001, limits of agreement = −0.43 to 0.33 L/min). The power at LT and VT did not differ (P = .6), and a significant association was observed (r = .73, P = .001, limits of agreement = −54.3 to 20.2 W, SEE = 26.1).Conclusions:This study indicates that MMW demonstrates a strong association with ergometer rowing performance and thus may have potential as an influential monitoring tool for rowing athletes.
Preliminary Evidence of Transient Fatigue and Pacing During Interchanges in Rugby League
Authors: Waldron Mark , Highton Jamie , Daniels Matthew , Twist Craig 
Published: August 2016

Purpose:This study aimed to quantify changes in heart rate (HR) and movement speeds in interchanged and whole-match players during 35 elite rugby league performances.Methods:Performances were separated into whole match, interchange bout 1, and interchange bout 2 and further subdivided into match quartiles. Mean percentages of peak HR (%HRpeak) and total and high-intensity running (> 14 km/h) meters per minute (m/min) were recorded.Results:For whole-match players, a decline in high-intensity m/min and %HRpeak was observed between successive quartiles (P < .05). High-intensity m/min during interchange 1 also progressively declined, although initial m/min was higher than whole match (24.2 ± 7.9 m/min vs 18.3 ± 4.7 m/min, P = .018), and %HRpeak did not change over match quartiles (P > .05). During interchange 2, there was a decline in high-intensity m/min from quartile 1 to quartile 3 (18 ± 4.1 vs 13.4 ± 5 m/min, P = .048) before increasing in quartile 4. Quartiles 1 and 2 also showed an increase in %HRpeak (85.2 ± 6.5 vs 87.3 ± 4.2%, P = .022).Conclusions:Replacement players adopted a high initial intensity in their first match quartile before a severe decline thereafter. However, in a second bout, lower exercise intensity at the outset enabled a higher physiological exertion for later periods. These findings inform interchange strategy and conditioning for coaches while also providing preliminary evidence of pacing in team sport.