bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.