bluuebunny/crossref_metadata_2025 huggingface dataset:
Kunst als Rückzug
Authors: Umathum Sandra
Published: November 2017

Dieser Beitrag beschäftigt sich mit verschiedenen Arbeiten, die sich als Rückzug aus einer fremdbestimmten Wiederkehr des Immergleichen in Szene setzen. Rückzug wird mithin zur Bedingung für eine selbst gewählte Reorganisation von Alltag und Alltäglichem und somit wiederum zur Bedingung für ein abseitiges Dasein bzw. eine Lebensweise, deren Abseitigkeit sich gerade dem temporären Ausstieg aus bestimmten Zusammenhängen und Gesetzmäßigkeiten verdankt, die künstlerische Praxis mit der permanenten Verpflichtung auf Kreativität verschalten. Die entsprechenden Arbeiten verfolgen unterschiedliche Interessen und Ziele; ihnen allen ist aber gemein, dass sie den Kreativitätsimperativ durch ihre Rückzüge im selben Maß reflexiv werden lassen wie die Vergeblichkeit, ihm konsequent zu entkommen.
The neurophysiology of working memory development: from childhood to adolescence and young adulthood
Authors: Gómez Carlos M. , Barriga-Paulino Catarina Isabel , Rodríguez-Martínez Elena Isabel , Rojas-Benjumea Ma Ángeles , Arjona Antonio , Gómez-González Jaime
Published: November 2017

Working memory (WM) is an important cognitive function that is necessary to perform our daily activities. The present review briefly describes the most accepted models underlying WM and the neural networks involved in its processing. The review focuses on how the neurophysiological mechanisms develop with age in the periods from childhood to adolescence and young adulthood. Studies using behavioral, neuroimaging, and electrophysiological techniques showed the progress of WM throughout the development. The present review focuses on the neurophysiology of the basic processes underlying WM operations, as indicated by electroencephalogram-derived signals, in order to take advantage of the excellent time resolution of this technique. Children and adults use similar cerebral mechanisms and areas to encode, recognize, and keep the stimuli in memory and update the WM contents, although adults rely more on anterior sites. The possibility that a functional reorganization of WM brain processing occurs around the adolescent period is suggested, and would partly justify the high prevalence of the emergence of mental pathology in the adolescent period.
Patientenselbstbestimmung als Ernstfall moderner praktischer Autonomie im Islam
Authors: Hibaoui Abdelmalek
Published: November 2017

Der Artikel beschreibt vor dem Hintergrund der Spannung zwischen Autonomie und Theonomie im Menschenbild des Islam, wie mit Fragen der Selbstbestimmung bei muslimischen Patientinnen und Patienten angesichts des Sterbens in einem westlichen, durch die moderne Medizin beeinflussten Kontext umgegangen werden kann. Auf der Grundlage eines islamischen Verständnisses des Todes als Erlösung und des Todeszeitpunkts als von Gott bestimmt, wird für eine größtmögliche Selbstbestimmung des sterbenden Menschen gegenüber einer drohenden Fremdbestimmung durch das Machbarkeitsdenken mancher Ausprägung der modernen Medizin plädiert. In diesem Zusammenhang wird sowohl zum Verfassen einer Patientenverfügung geraten als auch ein eigenständiges Beenden des Lebens durch einen ärztlich assistierten Suizid für Muslime ausgeschlossen.
Türkischstämmige Gesundheitspersonen in Deutschland: Der Diaspora-Effekt
Authors: Kuseyri Can
Published: November 2017

Hintergrund: Diese Studie untersucht erstmals, welche Einstellungen das türkischstämmige Medizinpersonal in Deutschland gegenüber Spiritualität und Religiosität in der Medizin hat, und welchen Einfluss diese Einstellungen auf die praktische medizinische Tätigkeit haben.Methode: 124 türkischstämmige medizinische Mitarbeiter (66 % Frauen, 72 % Ärzte, Pflegende, Medizinstudenten u. a.) füllten den Fragebogen NERSH aus, der deutschlandweit mit einem Weblink versendet wurde (Rücklaufrate 22,5 %). Ergebnisse: Es zeigte sich ein signifikanter Zusammenhang zwischen der selbsteingeschätzten Religiosität und dem Geburtsland (Deutschland oder Türkei) (p=.043). Die in Deutschland geborenen Befragten schätzten sich religiöser ein als ihre in der Türkei geborenen Kollegen. 84,4 % des türkischstämmigen Medizinpersonals fragte selten oder nie in proaktiver Weise nach spirituellen/religiösen Belangen eines Patienten/Angehörigen. Diese Zurückhaltung war unabhängig von selbsteingeschätzter Spiritualität, Religiosität und dem Geburtsland. Ein signifikanter Zusammenhang bestand zwischen dem Geburtsland und dem Einfluss eigener religiöser Überzeugungen auf die praktische medizinische Tätigkeit (n=66, p=.037). Während die Mehrheit (66,7 %) des Gesamtkollektivs einen solchen Einfluss verneinte, waren die in Deutschland geborenen Befragten eher dazu geneigt, diesem zuzustimmen. Diskussion: Diese Ergebnisse deuten auf die Auswirkungen der Minderheitensituation türkischstämmiger Gesundheitspersonen in Deutschland (Diaspora-Effekt) hin.
Shake the Tree or Rock the Boat: The Not Nice Protest and Radical Democracy in Israel
Authors: Levy Gal
Published: November 2017

What has remained of Israel’s tent encampments protest; what mark has it left on Israeli society and politics? This paper seeks to answer these two questions and to reflect on the “post-protest” protest. In reviewing the different accounts of the 2011 protest I propose to identify two political actors – the “hegemonic” and the “subaltern” – taking part in an agonic game which destabilized the neoliberal order. Central to the analysis is an activist group – The Not Nice

Trans.: The Not Nice invokes an utterance attributed to the then Israeli Prime Minister Golda Meir labeling the Mizrahi social protest leaders of the early 1970s as “Not Nice.” There is however a distinction in the Hebrew language between Female and Male voice and the activist group here was self-labeled Lo Nekhmadim-Lo Nekhmadot, i.e. The Not Nice (m) – The Not Nice (f). To distinguish between the two we will use hereafter ‘Not-Nice’ to refer to the female-led splinter group and ‘The Not Nice’ to the group as a whole. (I am using The Not Nice and Not-Nice in their chronological content; Not-Nice became more prevalent since the split in the group leading to greater female predominance).

– studied in consideration of its relations to the mainstream of the protest movement. The group’s activities and position challenge the conventional patterns of Israeli political discourse and its boundaries. It thus offers an opportunity to extend the discussion on citizenship and democracy beyond the liberal discourse and adopt the Radical Democracy theory as a conceptual framework to grasp present-day political reality.
Bioactive chemical constituents from the resin of Aloe vera
Authors: Rehman Najeeb Ur , Hussain Hidayat , Khiat Muhammaed , Khan Husain Yar , Abbas Ghulam , Green Ivan R. , Al-Harrasi Ahmed
Published: November 2017

Bioassay-guided fractionation of Aloe vera (L.) Burm.f. resulted in the isolation and characterization of one new C-glucosyl chromone, 7-methoxy-6′-O-coumaroylaloesin (1), along with the known dihydroisocoumarin feralolide (2). The structure of 1 was elucidated on the basis of 1D, 2D-NMR, and mass spectrometry. Both compounds 1 and 2 were tested for their effects on the growth of cancer cells in culture and it was observed that unlike compound 1, compound 2 displayed concentration-dependent antiproliferative effects on breast cancer cells (MDA-MB-231) and ovarian cancer cells (SKOV-3). Additionally, only feralolide (2) demonstrated good urease, weak α-glucosidase enzyme inhibition, and weak antioxidant effects.
Barriers to the Prescription of Psychological Strategies by Strength and Conditioning Specialists
Authors: Radcliffe Jon N. , Comfort Paul , Fawcett Tom
Published: November 2017

Radcliffe, JN, Comfort, P, and Fawcett, T. Barriers to the prescription of psychological strategies by strength and conditioning specialists. J Strength Cond Res 32(7): 1948–1959, 2018—The purpose of this article was to explore the barriers to strength and conditioning coaches integrating psychological strategies within the strength and conditioning practice. The sample of accredited strength and conditioning coaches comprised 10 subjects working within the United Kingdom, 3 within the United Sates, and 5 within Australia offering a cross section of experience from a range sporting disciplines and educational backgrounds. Subjects were interviewed using semistructured interviews and thematic clustering was used using interpretative phenomenological analysis to identify common themes. It was evident that not incorporating psychological strategies into strength and conditioning practice could be attributed to either internal, personally governed beliefs, or external, environmentally governed situations. Internal sources consisted of insufficient knowledge either regarding the value of psychological strategies or methods of implementing such techniques; in addition, the implementation of psychological techniques was outside the remit of the coach and difficulty existed in demonstrating the effectiveness of interventions. External causes consisted of a lack of time, insufficient control and authority of training session content, and athletes' negative perceptions. Recommendations are made on the basis of eliminating the observed barriers to the inclusion of psychological strategies. This included the use of education programs for both strength and conditioning coaches and organizational gatekeepers and the suggestion for increased collaboration with qualified psychologists.
Sex-Related Differences in the Accuracy of Estimating Target Force Using Percentages of Maximal Voluntary Isometric Contractions vs. Ratings of Perceived Exertion During Isometric Muscle Actions
Authors: Keller Joshua L. , Housh Terry J. , Smith Cory M. , Hill Ethan C. , Schmidt Richard J. , Johnson Glen O.
Published: November 2017

Keller, JL, Housh, TJ, Smith, CM, Hill, EC, Schmidt, RJ, and Johnson, GO. Sex-related differences in the accuracy of estimating target force using percentages of maximal voluntary isometric contractions vs. ratings of perceived exertion during isometric muscle actions. J Strength Cond Res 32(11): 3294–3300, 2018—The purpose of this study was to examine sex-related differences in the accuracy of estimating actual target force and to compare the accuracy of estimating actual target force using percentages of maximal voluntary isometric contraction (MVIC) or ratings of perceived exertion (RPE) values during isometric leg flexion and leg extension muscle actions. Twenty adults, 10 women and 10 men, (mean ± SD age: 22.9 ± 2.9 years) completed pretest MVICs to calculate actual target force values at 10, 30, 50, 70, and 90% of MVIC. Additional trials were then randomized for estimating actual target force using percentages of MVIC or RPE values during isometric leg flexion or leg extension. For isometric leg flexion, the women and men overestimated (p ≤ 0.05) the actual target force at 10% for the percentage of MVIC and RPE trials and underestimated the actual target force at 90% for the RPE trial. For isometric leg extension, the women overestimated the actual target force at 10% for the percentage of MVIC trial and RPE trial. The men overestimated actual target force at 10 and 30% for the percentage of MVIC trial and overestimated actual target force at 10% during the RPE trial for isometric leg extension. Also, the men underestimated actual target force at 90% for both the percentage of MVIC trial and RPE trial. Men require more familiarization than women to accurately estimate isometric leg extension force values. Caution should be used when estimating force production as a percentage of MVIC or RPE value for training prescriptions.
Effect of Jump Interval Training on Kinematics of the Lower Limbs and Running Economy
Authors: Ache-Dias Jonathan , Pupo Juliano Dal , Dellagrana Rodolfo A. , Teixeira Anderson S. , Mochizuki Luis , Moro Antônio R.P.
Published: November 2017

Ache-Dias, J, Pupo, JD, Dellagrana, RA, Teixeira, AS, Mochizuki, L, and Moro, ARP. Effect of jump interval training on kinematics of the lower limbs and running economy. J Strength Cond Res 32(2): 416–422, 2017—This study analyzed the effects of the addition of jump interval training (JIT) to continuous endurance training (40-minute running at 70% of peak aerobic velocity, 3 times per week for 4 weeks) on kinematic variables and running economy (RE) during submaximal constant-load running. Eighteen recreational runners, randomized into control group (CG) or experimental group (EG) performed the endurance training. In addition, the EG performed the JIT twice per week, which consisted of 4–6 bouts of continuous vertical jumping (30 seconds) with 5-minute intervals. The oxygen consumption (V̇o
2) during the submaximal test (performed at 9 km·h−1) was similar before (EG: 38.48 ± 2.75 ml·kg−1·min−1; CG: 36.45 ± 2.70 ml·kg−1·min−1) and after training (EG: 37.42 ± 2.54 ml·kg−1·min−1; CG: 35.81 ± 3.10 ml·kg−1·min−1). No effect of training, group, or interaction (p > 0.05) was found for RE. There was no interaction or group effect for the kinematic variables (p > 0.05). Most of the kinematic variables had a training effect for both groups (support time [p ≤ 0.05]; step rate [SR; p ≤ 0.05]; and step length [SL; p ≤ 0.05]). In addition, according to the practical significance analysis (percentage chances of a better/trivial/worse effect), important effects in leg stiffness (73/25/2), vertical stiffness (73/25/2), SR (71/27/2), and SL (64/33/3) were found for the EG. No significant relationship between RE and stiffness were found for EG and CG. In conclusion, the results suggest that JIT induces important changes in the kinematics of the lower limbs of recreational runners, but the changes do not affect RE.
Intracyclic Velocity Variation of the Center of Mass and Hip in Breaststroke Swimming With Maximal Intensity
Authors: Gourgoulis Vassilios , Koulexidis Stylianos , Gketzenis Panagiotis , Tzouras Grigoris
Published: November 2017

Gourgoulis, V, Koulexidis, S, Gketzenis, P, and Tzouras, G. Intra-cyclic velocity variation of the center of mass and hip in breaststroke swimming with maximal intensity. J Strength Cond Res 32(3): 830–840, 2018—The aim of the study was to compare the center of mass (CM) and hip (HIP) intracyclic velocity variation in breaststroke swimming using 3-dimensional kinematic analysis. Nine male breaststrokes, of moderate performance level, swam 25-m breaststroke with maximal intensity, and their movements were recorded, both under and above the water surface, using 8 digital cameras. Their CM and HIP velocities and their intracyclic variations were estimated after manual digitization of 28 selected points on the body in a complete arm and leg breaststroke cycle. Paired sample t-tests or Wilcoxon tests, when the assumption of normality was broken, were used for statistical analyses. In both, CM and HIP velocity-time curves, the results revealed a similar pattern of 2 clear peaks associated with the leg and arm propulsive phases and 2 minimal velocities that corresponded to the arm and leg recovery phase and the lag time between the leg and arm propulsive phases, respectively. However, despite this similar general pattern, the HIP minimum resultant velocity was significantly lower, whereas its maximal value was significantly greater, than the corresponding CM values. Consequently, the HIP intracyclic swimming velocity fluctuation significantly overestimates the actual variation of the swimmer's velocity in breaststroke swimming.
Reliability of Near-Infrared Spectroscopy for Measuring Intermittent Handgrip Contractions in Sport Climbers
Authors: Baláš Jiří , Kodejška Jan , Krupková Dominika , Hannsmann Johan , Fryer Simon
Published: November 2017

Baláš, J, Kodejška, J, Krupková, D, Hannsmann, J, and Fryer, S. Reliability of near-infrared spectroscopy for measuring intermittent handgrip contractions in sport climbers. J Strength Cond Res 32(2): 494–501, 2018—The use of near-infrared spectroscopy (NIRS) to investigate muscle oxygenation changes during physical tasks such as rock climbing has rapidly increased within recent years; yet, there is no known measure of reliability. The current study aimed to determine intersession reliability and minimal detectable change (MDC) of continuous wave NIRS parameters during intermittent handgrip contractions in rock climbers. Thirty-two sport climbers were tested for exhaustive intermittent handgrip exercise (8-second contraction–2-second relief) at 60% of maximal voluntary contraction on 3 separate days. During each visit, continuous wave NIRS was used to determine tissue saturation index (TSI) as the measure of tissue oxygenation in the flexor digitorum profundus. To assess the intersession reliability, the intraclass correlation coefficient (ICC), SEM, coefficient of variation (CV), and MDC were used. Mean deoxygenation during the contractions provided reliable results (∆ TSI; first trial −8.9 ± 2.9%, second trial −8.8 ± 2.7%, and third trial −8.4 ± 2.6%; ICC = 0.692; SEM = 1.5%; CV = 17.2%; MDC = 4.2%). Mean muscle reoxygenation during the relief periods was similarly reliable (∆ TSI; first trial 9.0 ± 3.1%, second trial 8.8 ± 2.9%, and third trial 8.5 ± 2.7%; ICC = 0.672; SEM = 1.7%; CV = 19.0%, MDC = 4.7%). As such, continuous wave NIRS provides a reliable measure of deoxygenation and reoxygenation during intermittent contractions to failure in the forearm flexors of rock climbers. Differences exceeding ∼4.5% for ∆ TSI during contraction and relief periods should be considered meaningful.
Running Performance in Brazilian Professional Football Players During a Congested Match Schedule
Authors: Palucci Vieira Luiz H. , Aquino Rodrigo , Lago-Peñas Carlos , Munhoz Martins Guilherme H. , Puggina Enrico F. , Barbieri Fabio A.
Published: November 2017

Palucci Vieira, LH, Aquino, R, Lago-Peñas, C, Munhoz Martins, GH, Puggina, EF, and Barbieri, FA. Running performance in Brazilian professional football players during a congested match schedule. J Strength Cond Res 32(2): 313–325, 2018—The purpose of the study was to examine the influence of playing congested fixtures (2 matches a week) on running performance of Brazilian professional football players, pooled (all performance files regardless players' rotation between games) or individualized data treatment (including only files of athletes' who played pair(s) of noncongested–congested matches which occurred on the same week). Forty participants were observed 1–37 times during 59 official matches over 3 years. Global positioning system devices were used to compute total distance covered, maximal sprinting speed mean speed (VAVERAGE), and high-intensity activities (HIA: ≥15 km·h−1). Independent variables included match status (win, draw, and lose), location (home and away), opponent quality (weak and strong), competitive standard (national and state), team formation (4-4-2 and 4-3-3), and position (defender, midfielder, and forward). Student's t-test, effect sizes (d), and magnitude-based inferences were performed to detect differences between congested and noncongested fixtures for each independent factor. Overall, pooled and individualized data treatment revealed contrasting results. The first showed chances of positive outcomes playing congested matches (possibly to very likely; d = 0.09–0.55), for all variables, as using 4-4-2 and state tournament. Conversely, individualized data analysis revealed that during national leagues (possibly; d = 0.24) or forward position (likely; d = 0.70), the players presented reduced HIA when played congested than noncongested periods (p ≤ 0.05). Using 4-3-3 (d = 0.26) or when draw (d = 0.41), possibly lower HIA was also identified. Coaching staff should be aware of performance oscillations such as detrimental effects on HIA during congested periods.
Performance Differences Among Skilled Soccer Players of Different Playing Positions During Vertical Jumping and Landing
Authors: Harry John R. , Barker Leland A. , James Roger , Dufek Janet S.
Published: November 2017

Harry, JR, Barker, LA, James, CR, and Dufek, JS. Performance differences among skilled soccer players of different playing positions during vertical jumping and landing. J Strength Cond Res 32(2): 304–312, 2018—Both jumping and landing performance of skilled soccer players is diminished when task demands are increased. However, it is unclear if performance changes are specific to players of certain playing positions. Therefore, we assessed jumping and landing performance among skilled soccer players of different playing positions. Twenty-five National Collegiate Athletic Association (NCAA) Division 1 male soccer players (179.5 ± 7.8 cm, 75.5 ± 7.1 kg, 19.7 ± 1.2 years) performed maximum effort vertical jump landings (VJLs), whereas vertical ground reaction force (vGRF) data were obtained. Participants were stratified into goalkeeping (GK), defensive (DEF), midfield (MID), and attacking (ATT) group according to their primary playing position. One-way analyses of variance (α = 0.05) and effect sizes (ESs; large ≥ 0.80) were used to compare differences among groups. The jumping phase variables evaluated were jump height, unloading and amortization vGRF magnitudes, eccentric rate of force development, and the reactive strength index. Landing phase variables included the peak vGRF magnitude, vGRF loading rate, vGRF attenuation rate, and landing time. No statistically significant differences were detected for any jumping or landing variable (p ≥ 0.05). However, a number of large magnitude differences were detected during landing after ES calculations. Specifically, greater peak vGRF magnitudes were detected in DEF vs. both MID (ES = 1.08) and ATT (ES = 0.93), a greater vGRF loading rate occurred in DEF vs. MID (ES = 0.93), and a greater vGRF attenuation rate occurred in DEF vs. both MID (ES = 1.00) and AT (ES = 0.80). It is concluded that highly skilled soccer players possess position-specific abilities with respect to the landing phase of VJL. Skilled soccer players might experience enhanced training outcomes after VJL training regimens tailored to the specific demands of their primary playing position.
Effect of Progressive Calisthenic Push-up Training on Muscle Strength and Thickness
Authors: Kotarsky Christopher J. , Christensen Bryan K. , Miller Jason S. , Hackney Kyle J.
Published: November 2017

Kotarsky, CJ, Christensen, BK, Miller, JS, and Hackney, KJ. Effect of progressive calisthenic push-up training on muscle strength and thickness. J Strength Cond Res 32(3): 651–659, 2018—Calisthenics, a form of resistance training, continue to increase in popularity; however, few studies have examined their effectiveness for muscle strength improvement. The purpose of this study was to determine whether progressive calisthenic push-up training (PUSH) is comparable with traditional bench press training (BENCH) as a technique for increasing muscle strength and thickness. Twenty-three healthy, moderately trained men (mean ± SD: age 23 ± 6.8 years) completed the study. Subjects were randomly assigned to PUSH (n = 14) and BENCH (n = 9) groups and were trained 3 days per week for 4 weeks. Muscle thickness (MT), seated medicine ball put (MBP), 1 repetition maximum (1RM) bench press, and push-up progression (PUP) were measured before and after training. Results revealed significant increases in 1RM (p < 0.001) and PUP (p < 0.001) for both groups after training. The increase in PUP was significantly greater for PUSH (p < 0.001). No significant differences were found within groups for MT and MBP (p > 0.05). This study is the first to demonstrate that calisthenics, using different progressive variations to maintain strength training programming variables, can improve upper-body muscle strength.
Stature, Body Mass, and Body Mass Index in High School American Football Players: Appropriate Determinants of Obesity Prevalence?
Authors: Mendez Alegra I. , Miramonti Amelia A. , Gillen Zachary M. , McKay Brianna D. , Leutzinger Todd J. , Cramer Joel T.
Published: November 2017

Mendez, AI, Miramonti, AA, Gillen, ZM, McKay, BD, Leutzinger, TJ, and Cramer, JT. Stature, body mass, and BMI in high school american football players: Appropriate determinants of obesity prevalence? J Strength Cond Res 32(11): 3119–3126, 2018—The purpose of this study was to evaluate stature (HT), mass (BM), body mass index (BMI), and obesity prevalence based on BMI categories in a large sample (n = 7,175) of high school American football players enrolled as freshmen, sophomores, or juniors. Players were categorized by their positions: offensive linemen (OLs), defensive linemen (DLs), tight end, defensive end, linebacker, running back, quarterback, defensive back, and wide receiver. The HT, BM, and BMI increased as grade increased among all positions. Offensive lineman and DL had the greatest HT, BM, and BMI (p ≤ 0.05). Obesity prevalence was greatest in OL and DL. When accounting for age-related increases in BMI, BM increased to a greater degree than HT. If HT is an indirect indicator of skeletal size, although BM is more influenced by soft tissue, then the age-related BMI increases in this study may be largely accounted for by soft-tissue changes rather than skeletal growth. Although obesity prevalence in OL (94.5%) and DL (78.4%) positions was greater than all other positions as determined from BMI, it is impossible to know the allocations of fat-free and fat mass—particularly in American football athletes. If obesity continues to be defined as an unhealthy accumulation of fat, then athletes who may have a greater relative proportion of lean soft tissue should not be classified as obese using BMI (BM ÷ HT2). More sophisticated, reliable, and sensitive measure of body composition, such as skinfolds, may be more appropriate field measurements.
Physical, Anthropometric, and Athletic Movement Qualities Discriminate Development Level in a Rugby League Talent Pathway
Authors: Pearce Leesa A. , Sinclair Wade H. , Leicht Anthony S. , Woods Carl T.
Published: November 2017

Pearce, LA, Sinclair, WH, Leicht, AS, and Woods, CT. Physical, anthropometric, and athletic movement qualities discriminate development level in a rugby league talent pathway. J Strength Cond Res 32(11): 3169–3176, 2018—This study compared the physical, anthropometric, and athletic movement qualities of talent-identified rugby league (RL) players within a development pathway. From a total of 174 players, 3 developmental levels were defined: under 18 (U18; n = 52), under 20 (U20; n = 53), and state league (SL; n = 69). All players performed a test battery that consisted of 5 physical assessments, 2 anthropometric measurements, and an athletic movement assessment. A multivariate analysis of variance modeled the main effect of developmental level (3 levels: U18, U20, and SL) on test criterion variables. Receiver-operating characteristic (ROC) curves were then built for the criterion variables that showed a significant developmental level effect. A significant effect was noted (V = 0.775, F = 5.43, p ≤ 0.05), with the SL players outperforming their U18 and U20 counterparts for measures of body mass, peak and average lower limb power, double lunge (left side), single-leg Romanian deadlift (left and right sides), the push-up, and total athletic ability assessment score (p ≤ 0.05; d = 0.35–1.21). The ROC curves generated an area under the curve of greater than 65% for each test criterion, indicating greater than chance discrimination. These results highlight the physical, anthropometric, and athletic movement qualities discriminant of development level within a RL talent pathway. Practitioners are encouraged to consider the thresholds from the ROC curves as an objective guide to assist with the development of physical performance qualities that may augment player progression in Australian RL.
The Effect of Citrulline Malate Supplementation on Muscle Fatigue Among Healthy Participants
Authors: Farney Tyler M. , Bliss Matthew V. , Hearon Christopher M. , Salazar Dassy A.
Published: November 2017

Farney, TM, Bliss, MV, Hearon, CM, and Salazar, DA. The effect of citrulline malate supplementation on muscle fatigue among healthy participants. J Strength Cond Res 33(9): 2464–2470, 2019—The focus of the investigation was to examine the effects of citrulline malate (CM) on muscular fatigue in healthy, recreationally trained participants. Twelve participants (men = 6 and women = 6) (24.1 ± 3.9 years) visited the laboratory on 3 separate days, all separated by 1 week. Each visit consisted of consuming 1 of 3 treatments: placebo, CM (8 g), and control in which no drink mixture was consumed. For each day of testing, participants consumed assigned treatment and performed 1 high-intensity exercise trial consisting of squats, lunge jumps, squat jumps, and lateral jumps. Participants performed the exercises in the listed order, which was designated as 1 round. Each participant performed 3 rounds, with the work-to-rest ratio being 20 seconds of work and 30 seconds of rest. A 1-minute rest was given between rounds. A pre/post-exercise isokinetic leg extension test was performed to measure for peak power, peak torque, and rate of fatigue. In addition, blood lactate was obtained pre/post-exercise. There were no treatment or interaction effects (p > 0.05) for peak torque, peak power, rate of fatigue, or blood lactate accumulation. However, there was a statistical significant decrease from pre/post-exercise for peak torque (p = 0.003), peak power (p = 0.003), and rate of fatigue (p = 0.001). In addition, lactate accumulation did increase significantly from pre/post-exercise (p = 0.0001). Finally, neither total work nor final heart rate was statistically significant between the treatments (p > 0.05). Citrulline malate was not effective in improving performance or alleviating fatigue after a high-intensity exercise session.
Changes in Energy Demand of Dance Activity and Cardiorespiratory Fitness During 1 Year of Vocational Contemporary Dance Training
Authors: Beck Sarah , Wyon Matthew A. , Redding Emma
Published: November 2017

Beck, S, Wyon, MA, and Redding, E. Changes in energy demand of dance activity and cardiorespiratory fitness during 1 year of vocational contemporary dance training. J Strength Cond Res 32(3): 841–848, 2018—Previous literature has demonstrated that the intensity of dance class as well as its discontinuous nature is not sufficient to elicit an aerobic training response and that the aerobic capacity of dancers is relatively low. These findings have raised questions on the suitability of training, through class and rehearsal, as adequate preparation for the physical demands of performance and a sustained, successful career in dance. The aim of this study was to describe changes in aerobic fitness and energy cost of dance movement occurring throughout 1 year of training. Subjects were 13 female dance students; 7 first-year undergraduate (UG) students, and 6 postgraduate (PG) students. At 3 time points (TP1, TP2, and TP3) during 1 academic year, each subject completed a treadmill test to determine V̇o
2peak (ml·kg−1·min−1) and lactate threshold (LT) (ml·kg−1·min−1 and %V̇o
2peak) and a standardized 4-minute dance sequence, where the mean demand was expressed as V̇o
2 (ml·kg−1·min−1), heart rate (b·min−1), %V̇o
2peak, and %LT. Both groups displayed an overall decrease in mean V̇o
2peak throughout the year, despite a peak in fitness at TP2 in the PG students. No significant changes in LT were noted over time for either group. A significant reduction in the relative intensity of the dance sequence, particularly in relation to mean Vo
2 (ml·kg−1·min−1) and %LT data, was observed over time in both groups, although the degree of change was less in the UG group than the PG group. Apparent adaptations during a rehearsal period in the PG group are presented in contrast to previous research findings. Recommendations for future research include further investigation into the energy demand of rehearsal and cardiorespiratory adaptation during rehearsal periods as well as further reporting of measures related to LT and movement economy.
Repeated Linear and Quadrangular Sprint as a Function of Anaerobic Power
Authors: Almansba Ramdane , Boucher Vincent G. , Parent Andrée-Anne , Comtois Alain S.
Published: November 2017

Almansba, R, Boucher, VG, Parent, AA, and Comtois, AS. Repeated linear and quadrangular sprint as a function of anaerobic power. J Strength Cond Res 33(8): 2177–2184, 2019—This investigation aims to study in U17 soccer players the relationships among performance indices of linear or quadrangular (square shape) repeated-sprint bouts (RSBs) and leg muscular power measured with the Wingate test and the squat jump. Seventeen athletes were recruited. Participants were 16 ± 0.35 years old and had a body mass of 66.5 ± 8.69 kg and a height of 175 ± 0.05 cm. All participants performed linear or quadrangular RSBs, the Wingate test, and a vertical jump test. The mean fast linear sprint time was strongly correlated (p < 0.01) with the force and power measured with the vertical jump test (r = −0.68 and −0.75, respectively), whereas the mean linear RSB was weakly correlated with the peak power and fatigue index measured by the Wingate test (r = −0.54 and −0.56, respectively). There was a correlation between quadrangular RSBs performance indices and both Wingate and vertical jump parameters. In addition, there were no correlations (p > 0.05) between indices of the linear RSBs (decrement index, average, and fastest times) and quadrangular RSBs. Moreover, physiological and perceptual responses were significantly higher (p < 0.01) with quadrangular RSBs compared with linear RSBs. These results indicate that the Wingate test and the vertical jump test can be used as a substitute for repeated-sprint performance time. Finally, however, the repeated sprints with or without direction changes are 2 different motor abilities that should be trained independently of one another.
The Relationship Between Multidirectional Jumping and Performance in Change of Direction Tasks
Authors: Bourgeois Frank A. , Gamble Paul , Gill Nic D. , McGuigan Mike R.
Published: November 2017

Bourgeois, FA II, Gamble, P, Gill, ND, and McGuigan, MR. The relationship between multidirectional jumping and performance in change of direction tasks. J Strength Cond Res 32(3): 690–699, 2018—This study investigated the test-retest reliability of 2 change of direction (COD; 180 and 45° COD) sprints and 3 multidirectional jump (MDJ) tests. Variables examined were approach time (sprint before plant-step), exit time (sprint after plant-step), total time (time to completion) and MDJ approach time, and distance, respectively. Second, the ability of MDJ tests to predict performance in COD tests was examined. Twenty men (age: 27.5 ± 5.9 years; height: 1.79 ± 0.1 m; and body mass: 79.1 ± 12.0 kg) performed 5 trials for each assessment, executing left plant-leg (LT) and right plant-leg (RT) steps, on 2 testing occasions separated by 7 days. Between-session and within-session intraclass correlation coefficients (ICCs) and coefficients of variation (CVs) for all measurements were calculated. Usefulness of COD and MDJ tests was assessed using typical error and smallest worthwhile change (SWC) comparison. Results showed only one MDJ measurement generated unstable between-session reliability. Within-session reliability of approach and exit COD times, and MDJ approach times possessed confidence limits (90% CL) that extended below 0.75 ICC. All COD total times and MDJ distances presented high reliability (ICC = 0.87–0.99) with low CV (0.9–4.1%). Right-leg MDJ distances were predictors of RT COD performances (r = 0.50–0.68, p = 0.001–0.024), whereas LT MDJ distances were predictors of LT180 COD performance (r = 0.67–0.71, p = 0.001). All measurements were useful in detecting SWC in performance. These findings suggest the COD tests and MDJ distances are reliable for assessing and monitoring COD performance in similar cohorts.
Independent and Combined Effects of Weight Status and Maturation on Aerobic Fitness in Adolescent School-Aged Males
Authors: Batista Mariana B. , Valente-dos-Santos João , Duarte João P. , Sousa-e-Silva Paulo , Coelho-e-Silva Manuel J. , Werneck André O. , Ohara David , Cyrino Edilson S. , Ronque Enio R.V.
Published: November 2017

Batista, MB, Valente-dos-Santos, J, Duarte, JP, Sousa-e-Silva, P, Coelho-e-Silva, MJ, Werneck, AO, Ohara, D, Cyrino, ES, and Ronque, ERV. Independent and combined effects of weight status and maturation on aerobic fitness in adolescent school-aged males. J Strength Cond Res 34(9): 2663–2671, 2020—This study aimed to examine the independent and combined effects of pubertal and weight status on concurrent measurements of peak oxygen (V̇o
2peak) in school-aged adolescent males. The final sample included 49 boys (12.3 ± 0.8 years). V̇o
2peak was derived from an incremental progressive maximal protocol using a motorized treadmill. In addition, maximal oxygen uptake was estimated from a 20-m shuttle run test. Static allometric models were obtained as an alternative to performance output per unit of size descriptors. Weight status had a significant effect on V̇o
2peak using simple ratio standards per unit of body mass (BM) with adolescents classified as overweight and obese (OWOB) attaining lower values of V̇o
2peak. A similar trend was noted for the allometric models adopting body mass (ml·kgBM
−0.542·min−1), stature (L·m−2.602·min), and fat-free mass (FFM; ml·kgFFM
−0.907·min−1). Findings also suggest the influence and interaction of pubertal and weight status on absolute values of V̇o
2peak. Considering the data obtained, linear equations to estimate V̇o
2peak from the 20-m shuttle run test should not be applied to boys who are OWOB because it will produce inaccurate assessments of cardiorespiratory fitness and penalize those who are heavier. Equations for V̇o
2peak prediction need to be specific for pubertal status and preferably consider FFM as a body size descriptor.
Energy Cost of Continuous Shuttle Running: Comparison of 4 Measurement Methods
Authors: Ciprandi Daniela , Lovecchio Nicola , Piacenza Marco , Limonta Eloisa , Esposito Fabio , Sforza Chiarella , Zago Matteo
Published: November 2017

Ciprandi, D, Lovecchio, N, Piacenza, M, Limonta, E, Esposito, F, Sforza, C, Zago, M. Energy cost of continuous shuttle running: Comparison of 4 measurement methods. J Strength Cond Res 32(8): 2265–2272, 2018—Assessing runs with frequent turns (shuttle run) is a viable option to evaluate the energy cost associated with sport-specific high-intensity intermittent activities. To date, no study investigated the extent to which the computation of energy cost of exercise is affected by the following factors: procedure and duration of oxygen uptake measurement during exercise, oxygen uptake measurement during recovery, estimation of the anaerobic alactic contribution, consideration of respiratory exchange ratio (RER) in the computation, and exercise intensity. Therefore, the aim of the current study was to determine whether these factors may lead to different estimations of the energy cost of locomotion. Twenty-six healthy young men participated in two 5-m shuttle-run trials at an average speed of 50 and 75% of their maximal aerobic velocity, respectively. Oxygen uptake and lactate concentration were measured before, during, and after the trials. Results revealed that different methods of computing the energy cost of 5-m shuttle run returned significantly different results, in particular at high intensity levels. The largest significant difference found between methods was lower than 10%. This suggests that for the most accurate computation of the workload, the contribution of the anaerobic alactic mechanisms and the influence of the RER cannot be neglected. These findings might help sport scientists and conditioning trainers in identifying the exercise conditions in which including all the metabolic components are required for an accurate computation of athletes' energy expenditure. In turn, exercise conditions would be defined where the computation could be conveniently simplified without worsening results reliability.
Importance of Speed and Power in Elite Youth Soccer Depends on Maturation Status
Authors: Murtagh Conall F. , Brownlee Thomas E. , O'Boyle Andrew , Morgans Ryland , Drust Barry , Erskine Robert M.
Published: November 2017

Murtagh, CF, Brownlee, TE, O'Boyle, A, Morgans, R, Drust, B, and Erskine, RM. Importance of speed and power in elite youth soccer depends on maturation status. J Strength Cond Res 32(2): 297–303, 2018—Maturation status is a confounding factor when identifying talent in elite youth soccer players (ESP). By comparing performance of ESP and control participants (CON) matched for maturation status, the aims of our study were to establish the importance of acceleration, sprint, horizontal-forward jump, and vertical jump capabilities for determining elite soccer playing status at different stages of maturation. Elite youth soccer players (n = 213; age, 14.0 ± 3.5 years) and CON (n = 113; age, 15.0 ± 4.4 years) were grouped using years from/to predicted peak height velocity (PHV) to determine maturation status (ESP: pre-PHV, n = 100; mid-PHV, n = 25; post-PHV, n = 88; CON: pre-PHV, n = 44; mid-PHV, n = 15; post-PHV, n = 54). Participants performed 3 reps of 10- and 20-m sprint, bilateral vertical countermovement jump (BV CMJ), and bilateral horizontal-forward CMJ (BH CMJ). Elite youth soccer players demonstrated faster 10-m (p < 0.001) and 20-m sprint (p < 0.001) performance than CON at all stages of maturation. Mid-PHV and post-PHV ESP achieved greater BV CMJ height (p < 0.001) and BH CMJ distance (ESP vs. CON; mid-PHV: 164.32 ± 12.75 vs. 136.53 ± 21.96 cm; post-PHV: 197.57 ± 17.05 vs. 168.06 ± 18.50 cm; p < 0.001) compared with CON, but there was no difference in BV or BH CMJ between pre-PHV ESP and CON. Although 10 and 20 m and sprint performance may be determinants of elite soccer playing status at all stages of maturation, horizontal-forward and vertical jumping capabilities only discriminate ESP from CON participants at mid- and post-PHV. Our data therefore suggest that soccer talent identification protocols should include sprint, but not jump assessments in pre-PHV players.
Validity and Reliability of the Load-Velocity Relationship to Predict the One-Repetition Maximum in Deadlift
Authors: Ruf Ludwig , Chéry Clément , Taylor Kristie-Lee
Published: November 2017

Ruf, L, Chéry, C, Taylor, KL. Validity and reliability of the load-velocity relationship to predict the 1RM in deadlift. J Strength Cond Res 32(3): 681–689, 2018—The aim of this study was to verify the reliability and validity of using submaximal loads from the load-velocity relationship to predict the actual 1 repetition maximum (1RM) in the deadlift. Data from 11 resistance-trained athletes were analyzed performing three 1RM assessments separated by at least 3 days. Reliability was assessed by comparing predicted 1RMs of sessions 2 and 3, whereas for validity purposes, predicted 1RMs of session 3 were compared with actual 1RMs of session 2. Mean concentric velocity at 1RM (v at 1RM) was entered in individualized linear regression equations, derived from the load-velocity relationship for 3 (20–60%, 40–80%, and 60–90% of 1RM), 4 (20–80% and 40–90% of 1RM), and 5 (20–90% of 1RM) incremental loads to predict 1RMs. There were trivial changes for all predicted 1RMs between sessions with 20–90% of 1RM being the most reliable model. Similarly, the actual 1RM was very stable (effect size [ES] = 0.04, 90% confidence limit [CL] [−0.03 to 0.12], typical error of measurement [TE] = 3.4 kg [2.5–5.4], intraclass coefficient [ICC] = 0.99 [0.96–0.996], and coefficient of variation [CV] = 1.9% [1.4–3.0]), whereas the v at 1RM was unreliable between trials (ES = −0.30, 90% CL [−0.78 to 0.17], TE = 0.029 m·s−1 [0.022–0.047], ICC = 0.63 [0.19–0.86], and CV = 15.7% [11.7–26.1]). However, predicted 1RMs computed from all submaximal load ranges substantially overestimated the actual 1RM with considerable differences between athletes. Although 1RM predictions showed high reliability, they all overestimated the actual 1RM, which was stable between sessions. Therefore, it is not recommended to apply the prediction models used in this study to compute daily 1RMs.
Effects of Plyometric and Directional Training on Speed and Jump Performance in Elite Youth Soccer Players
Authors: Beato Marco , Bianchi Mattia , Coratella Giuseppe , Merlini Michele , Drust Barry
Published: November 2017

Beato, M, Bianchi, M, Coratella, G, Merlini, M, and Drust, B. Effects of plyometric and directional training on speed and jump performance in elite youth soccer players. J Strength Cond Res 32(2): 289–296, 2018—Soccer players perform approximately 1,350 activities (every 4–6 seconds), such as accelerations/decelerations and changes of direction (CODs) during matches. It is well established that COD and plyometric training have a positive impact on fitness parameters in football players. This study analyzed the effect of a complex COD and plyometric protocol (CODJ-G) compared with an isolated COD protocol (COD-G) training on elite football players. A randomized pre-post parallel group trial was used in this study. Twenty-one youth players were enrolled in this study (mean ± SD; age 17 ± 0.8 years, mass 70.1 ± 6.4 kg, and height 177.4 ± 6.2 cm). Players were randomized into 2 different groups: CODJ-G (n = 11) and COD-G (n = 10), training frequency of 2 times a week more than 6 weeks. Sprint 10, 30, and 40 m, long jump, triple hop jump, and 505 COD test were considered. Exercise-induced within-group changes in performance for both CODJ-G and COD-G: long jump (effect size [ES] = 0.32 and ES = 0.26, respectively) and sprint 10 m (ES = −0.51 and ES = −0.22, respectively), after 6 weeks of training. Moreover, CODJ-G reported substantially better results (between-group changes) in long jump test (ES = 0.32). In conclusion, this study showed that short-term protocols (CODJ-G and COD-G) are important and able to give meaningful improvements on power and speed parameters in a specific soccer population. CODJ-G showed a larger effect in sprint and jump parameters compared with COD-G after the training protocol. This study offers important implications for designing COD and jumps training in elite soccer.
Impact of Weekly Swimming Training Distance on the Ergogenicity of Inspiratory Muscle Training in Well-Trained Youth Swimmers
Authors: Lomax Mitch , Kapus Jernej , Brown Peter I. , Faghy Mark
Published: November 2017

Lomax, M, Kapus, J, Brown, PI, and Faghy, M. Impact of weekly swimming training distance on the ergogenicity of inspiratory muscle training in well-trained youth swimmers. J Strength Cond Res 33(8): 2185–2193, 2019—The aim of this study was to examine the impact of weekly swimming training distance on the ergogenicity of inspiratory muscle training (IMT). Thirty-three youth swimmers were recruited and separated into a LOW and HIGH group based on weekly training distance (≤31 km·wk−1 and >41 km·wk−1, respectively). The LOW and HIGH groups were further subdivided into control and IMT groups for a 6-week IMT intervention giving a total of 4 groups: LOWcon, LOWIMT, HIGHcon, and HIGHIMT. Before and after the intervention period, swimmers completed maximal effort 100- and 200-m front crawl swims, with maximal inspiratory and expiratory mouth pressures (PImax and PEmax, respectively) assessed before and after each swim. Inspiratory muscle training increased PImax (but not PEmax) by 36% in LOWIMT and HIGHIMT groups (p ≤ 0.05), but 100- and 200-m swims were faster only in the LOWIMT group (3 and 7% respectively, p ≤ 0.05). Performance benefits only occurred in those training up to 31 km·wk−1 and indicate that the ergogenicity of IMT is affected by weekly training distance. Consequently, training distances are important considerations, among others, when deciding whether or not to supplement swimming training with IMT.