bluuebunny/crossref_metadata_2025 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.
What is Best Practice for Training Intensity and Duration Distribution in Endurance Athletes?
Authors: Seiler Stephen
Published: August 2016

Successful endurance training involves the manipulation of training intensity, duration, and frequency, with the implicit goals of maximizing performance, minimizing risk of negative training outcomes, and timing peak fitness and performances to be achieved when they matter most. Numerous descriptive studies of the training characteristics of nationally or internationally competitive endurance athletes training 10 to 13 times per week seem to converge on a typical intensity distribution in which about 80% of training sessions are performed at low intensity (2 mM blood lactate), with about 20% dominated by periods of high-intensity work, such as interval training at approx. 90% VO2max. Endurance athletes appear to self-organize toward a high-volume training approach with careful application of high-intensity training incorporated throughout the training cycle. Training intensification studies performed on already well-trained athletes do not provide any convincing evidence that a greater emphasis on high-intensity interval training in this highly trained athlete population gives long-term performance gains. The predominance of low-intensity, long-duration training, in combination with fewer, highly intensive bouts may be complementary in terms of optimizing adaptive signaling and technical mastery at an acceptable level of stress.
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.
Physical Characteristics, Physiological Attributes, and On-Field Performances of Soccer Goalkeepers
Authors: Ziv Gal , Lidor Ronnie
Published: August 2016

The soccer goalkeeper (GK) is required to perform strenuous actions during practice sessions and actual games. One of the objectives of those professionals who work with GKs is to obtain relevant information on physical characteristics and physiological attributes of GKs, and to use it effectively when planning training programs for them. This article has three purposes: (a) to review a series of studies (n = 23) on physical characteristics, physiological attributes, and on-field performances of soccer GKs; (b) to outline a number of methodological limitations and research concerns associated with these studies; and (c) to suggest several practical recommendations for soccer coaches who work with GKs. Four main fndings emerged from our review: (a) professional adult GKs usually are over 180 cm tall and have a body mass of over 77 kg; (b) studies on agility and speed produced mixed results, with some showing similar values between GKs and field players and others showing reduced performance in GKs; (c) GKs usually have higher vertical jump values when compared with players playing the various field positions; (d) GKs cover approximately 5.5 km during a game, mostly by walking and jogging. Four methodological limitations and research concerns associated with the reviewed studies were discussed, among them the lack of a longitudinal approach and the lack of on-field performance studies. Three practical recommendations are made for coaches, one of which is that coaches should adopt a careful approach when selecting testing protocols and devices for the assessment of GKs’ physiological attributes.
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.
Kenyan and Ethiopian Distance Runners: What Makes Them so Good?
Authors: Wilber Randall L. , Pitsiladis Yannis P.
Published: August 2016

Since the 1968 Mexico City Olympics, Kenyan and Ethiopian runners have dominated the middle- and longdistance events in athletics and have exhibited comparable dominance in international cross-country and roadracing competition. Several factors have been proposed to explain the extraordinary success of the Kenyan and Ethiopian distance runners, including (1) genetic predisposition, (2) development of a high maximal oxygen uptake as a result of extensive walking and running at an early age, (3) relatively high hemoglobin and hematocrit, (4) development of good metabolic “economy/efficiency” based on somatotype and lower limb characteristics, (5) favorable skeletal-muscle-fiber composition and oxidative enzyme profile, (6) traditional Kenyan/Ethiopian diet, (7) living and training at altitude, and (8) motivation to achieve economic success. Some of these factors have been examined objectively in the laboratory and field, whereas others have been evaluated from an observational perspective. The purpose of this article is to present the current data relative to factors that potentially contribute to the unprecedented success of Kenyan and Ethiopian distance runners, including recent studies that examined potential links between Kenyan and Ethiopian genotype characteristics and elite running performance. In general, it appears that Kenyan and Ethiopian distance-running success is not based on a unique genetic or physiological characteristic. Rather, it appears to be the result of favorable somatotypical characteristics lending to exceptional biomechanical and metabolic economy/efficiency; chronic exposure to altitude in combination with moderate-volume, high-intensity training (live high + train high), and a strong psychological motivation to succeed athletically for the purpose of economic and social advancement.
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.
Amateur Boxing: Activity Profile of Winners and Losers
Authors: Davis Philip , Wittekind Anna , Beneke Ralph
Published: August 2016

An activity profile of competitive 3 × 2-min novice-level amateur boxing was created based on video footage and postbout blood [La] in 32 male boxers (mean ± SD) age 19.3 ± 1.4 y, body mass 62.6 ± 4.1 kg. Winners landed 18 ± 11 more punches than losers by applying more lead-hand punches in round 1 (34.2 ± 10.9 vs 26.5 ± 9.4), total punches to the head (121.3 ± 10.2 vs 96.0 ± 9.8), and block and counterpunch combinations (2.8 ± 1.1 vs. 0.1 ± 0.2) over all 3 rounds and punching combinations (44.3 ± 6.4 vs 28.8 ± 6.7) in rounds 1 and 3 (all P < .05). In 16 boxers, peak postbout blood [La] was 11.8 ± 1.6 mmol/L irrespective of winning or losing. The results suggest that landing punches requires the ability to maintain a high frequency of attacking movements, in particular the lead-hand straight punch to the head together with punching combinations. Defensive movements must initiate a counterattack. Postbout blood [La] suggests that boxers must be able to tolerate a lactate production rate of 1.8 mmol · L−1 · min−1 and maintain skillful techniques at a sufficient activity rate.
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.
Do Physical Capacity and Interchange Rest Periods Influence Match Exercise-Intensity Profile in Australian Football?
Authors: Mooney Mitchell , Cormack Stuart , O’Brien Brendan , Coutts Aaron J
Published: August 2016

Purpose:

The purpose of this study was to determine if Yo-Yo Intermittent Recovery level 2 (Yo-Yo IR2) and the number of interchange rotations affected the match activity profile of elite Australian footballers.

Method:

Fifteen elite Australian footballers completed the Yo-Yo IR2 before the beginning of the season and played across 22 matches in which match activity profiles were measured via microtechnology devices containing a global positioning system (GPS) and accelerometer. An interchange rotation was counted when a player left the field and was replaced with another player. Yo-Yo IR2 results were further split into high and low groups.

Results:

Players match speed decreased from 1st to 4th quarter, while average-speed (m/min: P = .05) and low-speed activity (LSA, <15 km/h) per minute (LSA m/min; P = .06) significantly decreased in the 2nd half. Yo-Yo IR2 influenced the amount of m/min, high-speed running (HSR, >15 km/h) per minute (HSR m/min) and accelerometer load/min throughout the entire match. The number of interchanges significantly influenced the HSR m/min and m/min throughout the match except in the 2nd quarter. Furthermore, the low Yo-Yo IR2 group had significantly less LSA m/min in the 4th quarter than the high Yo-Yo IR2 group (92.2 vs 96.7 m/min, P = .06).

Conclusions:

Both the Yo-Yo IR2 and number of interchanges contribute to m/min and HSR m/min produced by elite Australian footballers, affecting their match activity. However, while it appears that improved Yo-Yo IR2 performance prevents reductions in LSA m/min during a match, higher-speed activities (HSR m/min) and overall physical activity (m/min and load/min) are still reduced in the 4th quarter compared with the 1st quarter.
Effects of Ramadan on the Diurnal Variations of Repeated-Sprint Performance
Authors: Aloui Asma , Chaouachi Anis , Chtourou Hamdi , Wong Del P. , Haddad Monoem , Chamari Karim , Souissi Nizar
Published: August 2016

Purpose:

This study examined the effects of Ramadan on cycling repeated-sprint ability (RSA) and corresponding diurnal variations.

Methods:

Twelve active men performed an RSA test (5 × 6-s maximal sprints interspersed with 24 s passive recovery) during morning and afternoon sessions 1 wk before Ramadan (BR), during the second (R2) and the fourth (R4) weeks of Ramadan, and 2 wk after Ramadan (AR). Maximal voluntary contraction was assessed before (MVCpre), immediately after (MVCpost), and 5 min after the RSA test (MVCpost5). Moreover, hematocrit, hemoglobin, and plasma sodium and potassium (K+) concentrations were measured at rest and after the RSA test and MVCpost.

Results:

Overall, peak power (Ppeak) during the RSA test decreased throughout the 5 sprints. Ppeak measured in the first sprint and MVCpre were lower during Ramadan than BR in the afternoon (P < .05) and higher in the afternoon than the morning BR and AR (P < .05). However, this diurnal rhythmicity was not found for the last 4 sprints’ Ppeak, MVCpost, and MVCpost5 in all testing periods. Furthermore, the last 4 sprints’ Ppeak, MVCpost, MVCpost5, and morning MVCpre were not affected by Ramadan. [K+] measured at rest and after the RSA test and MVCpost were higher during Ramadan than BR in the afternoon (P < .05) and higher in the afternoon than the morning during Ramadan (P < .05).

Conclusions:

Fatigability is higher in the afternoon during Ramadan, and, therefore, training and competition should be scheduled at the time of day when physical performance is less affected.
Cardiac Autonomic Adaptations in Elite Spanish Soccer Players During Preseason
Authors: Boullosa Daniel A. , Abreu Laurinda , Nakamura Fábio Y. , Muñoz Víctor E. , Domínguez Eduardo , Leicht Anthony S.
Published: August 2016

Purpose:

The purpose of this study was to evaluate changes in autonomic control of heart rate (HR) and fitness in a group of elite soccer players during the preseason.

Methods:

Eight professional male soccer players competing in the Spanish First Division were evaluated in July (wk 1) and September (wk 8) with night-time HR variability (HRV) over 4 different days, ultra-short-term HR recovery (HRR) during a small-sided-games session, Yo-Yo Intermittent Recovery test level 1 (Yo-Yo IR1), and a field test for determination of maximum aerobic speed.

Results:

Players exhibited a greater HRV and a faster ultra-short-term HRR at wk 8, with the players with a lower HRV at wk 1 exhibiting the greatest improvements at wk 8. However, there were unclear improvements in performance parameters, with maximum HR (HRmax) being reduced over the preseason period. This change in HRmax was correlated with the change in short-term HRV parameters (ρ = 0.829, P = .042). Large correlations were observed among HRV, ultra-short-term HRR, and field performance parameters only at wk 8. Furthermore, the variation (%) of the root-mean-square of successive differences between R-R intervals was increased during the preseason (12.95% ± 15.14% to 29.39% ± 21.93%, P = .013) and significantly correlated (r = .898, P = .006) with Yo-Yo IR1 performance (~2600 ± 786 m) at wk 8.

Conclusions:

The current results support the appropriateness and practicality of night-time HRV and ultra-short-term HRR for evaluation of autonomic adaptations in professional soccer players, despite the unclear improvements in specific field performance parameters.
The Effect of Time of Day on Cold Water Ingestion by High-Level Swimmers in a Tropical Climate
Authors: Hue Olivier , Monjo Roland , Lazzaro Marc , Baillot Michelle , Hellard Philippe , Marlin Laurent , Jean-Etienne A.
Published: August 2016

The authors tested the effect of cold water ingestion during high-intensity training in the morning vs the evening on both core temperature (TC) and thermal perceptions of internationally ranked long-distance swimmers during a training period in a tropical climate. Nine internationally ranked long-distance swimmers (5 men and 4 women) performed 4 randomized training sessions (2 in the evening and 2 in the morning) with 2 randomized beverages with different temperatures for 3 consecutive days. After a standardized warm-up of 1000 m, the subjects performed a standardized training session that consisted of 10 × 100 m (start every 1′20″) at a fixed velocity. The swimmers were then followed for the next 3000 m of the training schedule. Heart rate (HR) was continuously monitored during the 10 × 100 m, whereas TC, thermal comfort, and thermal sensation (TS) were measured before and after each 1000-m session. Before and after each 1000 m, the swimmers were asked to drink 190 mL of neutral (26.5 ± 2.5°C) or cold (1.3 ± 0.3°C) water packaged in standardized bottles. Results demonstrated that cold water ingestion induced a significant effect on TC, with a pronounced decrease in the evening, resulting in significantly lower mean TC and lower mean delta TC in evening cold (EC) than in evening neutral (EN), concomitant with significantly lower TS in EC than in EN and a significant effect on exercise HR. Moreover, although TC increased significantly with time in MN, MC, and EN, TC was stabilized during exercise in EC. To conclude, we demonstrate that a cold beverage had a significant effect on TC, TS, and HR during training in high-level swimmers in a tropical climate, especially during evening training.
The Alphabet of Sport Science Research Starts With Q
Authors: Mujika Iñigo
Published: August 2016

The training stimulus in competitive sports is usually described as a combination of training intensity, volume and frequency. It is generally believed that these three factors produce an adaptive response in the body that should lead to improved performance.1,p395
Determining Anaerobic Capacity in Sporting Activities
Authors: Noordhof Dionne A. , Skiba Philip F. , de Koning Jos J.
Published: August 2016

Anaerobic capacity/anaerobically attributable power is an important parameter for athletic performance, not only for short high-intensity activities but also for breakaway efforts and end spurts during endurance events. Unlike aerobic capacity, anaerobic capacity cannot be easily quantified. The 3 most commonly used methodologies to quantify anaerobic capacity are the maximal accumulated oxygen deficit method, the critical power concept, and the gross efficiency method. This review describes these methods, evaluates if they result in similar estimates of anaerobic capacity, and highlights how anaerobic capacity is used during sporting activities. All 3 methods have their own strengths and weaknesses and result in more or less similar estimates of anaerobic capacity but cannot be used interchangeably. The method of choice depends on the research question or practical goal.
Contemporary Nutrition Approaches to Optimize Elite Marathon Performance
Authors: Stellingwerff Trent
Published: August 2016

The professionalization of any sport must include an appreciation for how and where nutrition can positively affect training adaptation and/or competition performance. Furthermore, there is an ever-increasing importance of nutrition in sports that feature very high training volumes and are of a long enough duration that both glycogen and fluid balance can limit performance. Indeed, modern marathon training programs and racing satisfy these criteria and are uniquely suited to benefit from nutritional interventions. Given that muscle glycogen is limiting during a 2-h marathon, optimizing carbohydrate (CHO) intake and delivery is of maximal importance. Furthermore, the last 60 y of marathon performance have seen lighter and smaller marathoners, which enhances running economy and heat dissipation and increases CHO delivery per kg body mass. Finally, periodically training under conditions of low CHO availability (eg, low muscle glycogen) or periods of mild fluid restriction may actually further enhance the adaptive responses to training. Accordingly, this commentary highlights these key nutrition and hydration interventions that have emerged over the last several years and explores how they may assist in world-class marathon performance.
High-Intensity Intermittent Exercise: Methodological and Physiological Aspects
Authors: Tschakert Gerhard , Hofmann Peter
Published: August 2016

High-intensity intermittent exercise (HIIE) has been applied in competitive sports for more than 100 years. In the last decades, interval studies revealed a multitude of beneficial effects in various subjects despite a large variety of exercise prescriptions. Therefore, one could assume that an accurate prescription of HIIE is not relevant. However, the manipulation of HIIE variables (peak workload and peak-workload duration, mean workload, intensity and duration of recovery, number of intervals) directly affects the acute physiological responses during exercise leading to specific medium- and long-term training adaptations. The diversity of intermittent-exercise regimens applied in different studies may suggest that the acute physiological mechanisms during HIIE forced by particular exercise prescriptions are not clear in detail or not taken into consideration. A standardized and consistent approach to the prescription and classification of HIIE is still missing. An optimal and individual setting of the HIIE variables requires the consideration of the physiological responses elicited by the HIIE regimen. In this regard, particularly the intensities and durations of the peak-workload phases are highly relevant since these variables are primarily responsible for the metabolic processes during HIIE in the working muscle (eg, lactate metabolism). In addition, the way of prescribing exercise intensity also markedly influences acute metabolic and cardiorespiratory responses. Turn-point or threshold models are suggested to be more appropriate and accurate to prescribe HIIE intensity than using percentages of maximal heart rate or maximal oxygen uptake.
Stress and Recovery Balance in Amateur Basketball Players: Differences by Gender and Preparation Phase
Authors: di Fronso Selenia , Nakamura Fabio Y. , Bortoli Laura , Robazza Claudio , Bertollo Maurizio
Published: August 2016

The aim of the study was to examine differences in stress and recovery across gender and time (preseason and play-offs) in a sample of amateur basketball players of the Italian league (C division). Fifty amateur basketball players (33 men and 17 women) age 17–30 y (23.5 ± 9.19 y) participated in the study. Twenty-eight athletes (16 men and 12 women) completed the Recovery-Stress Questionnaire for Sport (RESTQ-Sport) in the preseason phase, after a training period of 21 days, and in the competition phase during the play-off period. Repeated-measures MANOVA showed significant differences by gender and preparation phase. Univariate follow-up ANOVA highlighted differences by gender on physical recovery, sleep quality, and self-efficacy, with higher scores in men. Moreover, differences between preseason and competition phases were shown on emotional stress and fatigue, with higher scores on emotional stress and lower scores on fatigue in the competition phase. These findings suggest that RESTQ-Sport could be a useful tool for coaches to monitor stress/recovery balance in male and female team-sport athletes during different periods of the season.
Morphological and Physiological Profile of Elite Basketball Players in Belgium
Authors: Boone Jan , Bourgois Jan
Published: August 2016

Purpose:

The current study aimed to gain insight into the physiological profile of elite basketball players in Belgium in relation to their position on the field.

Methods:

The group consisted of 144 players, divided into 5 groups according to position (point guards [PGs], shooting guards [SGs], small forwards [SFs], power forwards [PFs], and centers [Cs]). The anthropometrics were measured and the subjects underwent fitness tests (incremental running test, 10-m sprint, 5 ×-10 m, squat and countermovement jump, isokinetic test) to obtain insight into endurance, speed, agility, and power. The parameters of these tests were compared among the different positions by means of 1-way variance analysis (MANOVA). Tukey post hoc tests were performed in case of a significant MANOVA.

Results:

It was observed that Cs were taller and heavier and had a higher percentage body fat than PGs and SGs. For the anaerobic sprint test Cs were slower than the other positions. For the 5 × 10-m the PGs and SGs were faster than SFs and PFs. For the jump test Cs displayed a significantly lower absolute performance than the other positions. PGs and SGs had a higher VO2peak and speed at the anaerobic threshold than PFs and Cs. The isokinetic strength test showed that the quadriceps muscle group of Cs could exert a higher torque during knee extension than the other positions.

Conclusions:

The current study showed that the physiological profile of elite players in the Belgian first division differs by player position. More specifically, guards were characterized by high endurance, speed, and agility, whereas centers and power forwards had higher muscle strength than the other positions.
Body Segment Contributions to Javelin Throwing during Final Thrust Phases
Authors: Antti Mero , Komi Paavo V. , Korjus Tapio , Navarro Enrique , Gregor Robert J.
Published: August 2016

This study investigated body segment contributions to javelin throwing during the last thrust phases. A 3-D analysis was performed on male and female javelin throwers during the finals of the 1992 Olympic Games in Barcelona. The subjects were videotaped from the right sight of the throwing area by two NAC high-speed cameras operating at 100 frames per second. Both men’s and women’s grip of javelin and body center of mass displayed a curved pathway to the right from the left (bracing) foot during the final foot contact. The position of the body center of mass decreased at the beginning of the final foot contact, but after the decrease period it began to increase. Simultaneously with the increase, the peak joint center speeds occurred in a proper sequence from proximal to distal segments and finally to the javelin at release. Release speed correlated significantly with throwing distance in both male and females.
A Profile of Ground Reaction Forces in Professional Basketball
Authors: McClay Irene S. , Robinson John R. , Andriacchi Thomas P. , Frederick Edward C , Gross Ted , Martin Philip , Valiant Gordon , Williams Keith R. , Cavanagh Peter R.
Published: August 2016

Basketball is a sport that involves multiple impacts with the ground through a variety of moves such as running Jumping, and cutting. Repetitive impacts have been associated with stress-related injuries in other sports such as running. The purpose of this investigation was to gain an understanding of the typical stresses the body experiences during common basketball moves. To this end, the ground reaction forces from 24 players from five professional basketball teams were studied. In addition, a game analysis was performed to determine the frequency of selected moves. These data indicated that certain common movements, such as jump landings and shuffling, resulted in absolute and relative forces much greater than many of those reported previously in studies of other sports. These movements were also identified in a companion paper as being associated with large angular excursions and velocities. Findings are discussed with respect to injury risks, and suggestions for future study are made.
Segment Interactions of the Arm during the Practice of a Novel, Multijoint Throwing Skill
Authors: Heise Gary D.
Published: August 2016

The purpose of this investigation was to determine, for a planar, multijoint throwing skill, if the interactions of segment energetics change over the course of practice. Eighteen men threw a weighted ball with their dominant arm at a target while the motion was restrained to a horizontal plane. From video data and body segment inertia! estimations, the energy transferred by the net joint force and the mechanical work attributed to the net joint moment were calculated for selected practice trials. Performance scores showed an expected improvement over trial blocks. An energetics analysis indicated that, for the throw, the mechanical work generated by muscle and transferred through muscle (i.e., via the net joint moment) across the elbow joint and the energy transferred by the net joint force across the wrist joint increased early in practice; however, no changes were observed in the relative contributions made by these components. The results indicated that, although performance increased significantly, the movement strategy used by subjects was intact throughout practice.