bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship Among Repeated Sprint Ability, Chronological Age, and Puberty in Young Soccer Players
Authors: Perroni Fabrizio , Pintus Antonio , Frandino Mattia , Guidetti Laura , Baldari Carlo
Published: February 2017

Perroni, F, Pintus, A, Frandino, M, Guidetti, L, and Baldari, C. Relationship among repeated sprint ability, chronological age, and puberty in young soccer players. J Strength Cond Res 32(2): 364–371, 2018—The aim of this study was to analyzed the relationship of repeated sprint ability (RSA) with chronological age and puberty in 100 young soccer players (age: 13 ± 3 years–160 ± 33 months-; height: 159 ± 16 cm, mass: 49.7 ± 14.1 kg; body mass index [BMI] 19.2 ± 2.5 kg/m2) grouped on “Pulcini” (9–10 years), “Esordienti” (11–12 years), “Giovanissimi” (13–14 years), “Allievi” (15–16 years), and “Juniores” (>17 years) categories. Anthropometric (weight, height, BMI), RSA (7 × 30 m sprint with 25 seconds active rest: total time—TT, the lowest sprinting time, and the fatigue index percentage—%IF), and development (self-administered rating scale for pubertal development PDS; puberty) parameters were measured. ANOVA among categories was applied to asses differences (p ≤ 0.05) in TT and %IF. When a significant effect was found, Bonferroni's post hoc analysis was used. Pearson correlation among all variables was calculated considering all subjects and also within categories. Among categories, statistical analysis showed significant differences (p < 0.001) in TT and a considerable trend toward significance (p = 0.06) in %IF. Significant correlations among variables were found in all subjects and within categories. In particular, TT showed large significant correlation with PDS (r = −0.66) and puberty (r = −0.67) only in “Esordienti.” This study provides useful information for the coach to propose an appropriate training and to obtain the optimal training effect and to minimize the risk of injury and overtraining during the different phases of growth and maturation.
Heart Rate Variability During Exercise: A Comparison of Artefact Correction Methods
Authors: Giles David A. , Draper Nick
Published: February 2017

Giles, DA and Draper, N. Heart rate variability during exercise: a comparison of artefact correction methods. J Strength Cond Res 32(3): 726–735, 2018—There is a need for standard practice in the collection and processing of RR interval data recorded using heart rate monitors (HRMs) in research. This article assessed the validity of RR intervals and heart rate variability (HRV) data obtained using an HRM during incremental exercise and artefact correction methods. Eighteen participants completed an active orthostatic test and incremental running V̇o
2max test, while simultaneous recordings using a Polar V800 HRM and an electrocardiogram were made. Artefacts were corrected by deletion; degree zero, linear, cubic, and spline interpolation; and Kubios HRV software. Agreement was assessed using percentage bias, effect size (ES), intraclass correlation coefficients (ICC), and Bland-Altman limits of agreement (LoA). Artefacts increased relative to exercise intensity, to a peak of 4.46% during 80–100% V̇o
2max. Correction of RR intervals was necessary with unacceptably increased bias, LoA, and ES and reduced ICC in all but resting recordings. All correction methods resulted in data with reduced percentage bias and ES for resting and <60% V̇o
2max recordings. However, at >60% V̇o
2max, even with correction, large amounts of variation were present in HRV measures of root mean square of the successive difference of intervals, low-to-high frequency ratio, Poincaré dispersion perpendicular to the axis (SD1), and sample entropy. Linear interpolation produced RR intervals with the lowest bias and ES. However, caution should be given to HRV parameters at high exercise intensities, as large amounts of variation were still present. Recommendations for minimizing artefacts are discussed, along with guidelines for their identification, correction, and reporting.
Short-Term Training Cessation as a Method of Tapering to Improve Maximal Strength
Authors: Pritchard Hayden J. , Barnes Matthew J. , Stewart Robin J.C. , Keogh Justin W.L. , McGuigan Michael R.
Published: February 2017

Pritchard, HJ, Barnes, MJ, Stewart, RJC, Keogh, JWL, and McGuigan, MR. Short-term training cessation as a method of tapering to improve maximal strength. J Strength Cond Res 32(2): 458–465, 2018—The aim of this study was to determine the effects of 2 different durations of training cessation on upper- and lower-body maximal strength performance and to investigate the mechanisms underlying performance changes following short-term training cessation. Eight resistance trained males (23.8 ± 5.4 years, 79.6 ± 10.2 kg, 1.80 ± 0.06 m, relative deadlift 1 repetition maximum of 1.90 ± 0.30 times bodyweight [BW]) each completed two 4-week strength training periods followed by either 3.5 days (3.68 ± 0.12 days) or 5.5 days (5.71 ± 0.13 days) of training cessation. Testing occurred pretraining (T1), on the final day of training (T2), and after each respective period of training cessation (T3). Participants were tested for salivary testosterone and cortisol, plasma creatine kinase, psychological profiles, and performance tests (countermovement jump [CMJ], isometric midthigh pull, and isometric bench press [IBP]) on a force plate. Participants' BW increased significantly over time (p = 0.022). The CMJ height and IBP peak force showed significant increases over time (p = 0.013, 0.048, and 0.004, respectively). Post hoc testing showed a significant increase between T1 and T3 for both CMJ height and IBP peak force (p = 0.022 and 0.008 with effect sizes of 0.30 and 0.21, respectively). No other significant differences were seen for any other measures. These results suggest that a short period of strength training cessation can have positive effects on maximal strength expression, perhaps because of decreases in neuromuscular fatigue.
Differences by Ending Rounds and Other Rounds in Time-Motion Analysis of Mixed Martial Arts: Implications for Assessment and Training
Authors: Miarka Bianca , Brito Ciro J. , Moreira Danilo G. , Amtmann John
Published: February 2017

Miarka, B, Brito, CJ, Moreira, DG, and Amtmann, J. Differences by ending rounds and other rounds in time-motion analysis of mixed martial arts: implications for assessment and training. J Strength Cond Res 32(2): 534–544, 2018—This study aimed to support training program development through the comparison of performance analysis of professionals mixed martial art (MMA) athletes in the bouts that were not finished by points. Using digital recordings of each bout, we analyzed 1,564 rounds (678 bouts) which were separated by ending and other rounds. Our results indicated that knockout/technical knockout is the main outcome that defines the ending round (≈60%); however, there is a higher frequency of ending by submission on the first and second rounds (>30%). Bouts ending during the first or second rounds had shorter total time and standing combat with low intensity than ending in the third round (91.5 ± 71.4, 93.4 ± 67.5, and 143.2 ± 87.4; for low intensity in the first, second, and third rounds, respectively; p ≤ 0.05), whereas standing combat time with high intensity was longer in the last round in comparison to bouts that finished in the first or second rounds (7.4 ± 9.2, 9.7 ± 18.0, and 17.7 ± 29.1 for high intensity in the first, second, and third rounds, respectively; p ≤ 0.05). The lower time dedicated to low-intensity stand-up combat actions, regardless of round, and forcefulness of the actions in groundwork in the first and second rounds seem to be elements that increase the probability of success in professional MMA bouts; these factors have essential implications related to training program design.
Delayed Effects of a Low-Volume, Power-Type Resistance Exercise Session on Explosive Performance
Authors: Tsoukos Athanasios , Veligekas Panagiotis , Brown Lee E. , Terzis Gerasimos , Bogdanis Gregory C.
Published: February 2017

Tsoukos, A, Veligekas, P, Brown, LE, Terzis, G, and Bogdanis, GC. Delayed effects of a low-volume, power-type resistance exercise session on explosive performance. J Strength Cond Res 32(3): 643–650, 2018—This study examined the delayed effects of a power-type training session on explosive performance. Seventeen well-trained male power and team sport athletes (age: 22.7 ± 5.5 years, height: 181 ± 8 cm, body mass: 80.7 ± 8.6 kg, body fat: 9.2 ± 1.7%, 1 repetition maximum (1RM) half-squat: 163 ± 29 kg) performed 4 sessions (2 experimental and 2 control) 1 week apart in a randomized and counterbalanced order. Explosive performance was assessed before, 24 and 48 hours after a low-volume, power-type training session (5 × 4 jump squats at 40% 1RM with 3 minutes rest), as well as before and after 24 and 48 hours of rest (control). Dependent variables were as follows: countermovement jump (CMJ), reactive strength index (RSI) during a drop jump, leg press maximum isometric force, and rate of force development (RFD) at 3 time windows: 0–100, 0–200, and 0–300 milliseconds. Analysis of variance revealed no changes in the control conditions. In contrast after training, CMJ was improved by 5.1 ± 1.0% and 3.0 ± 1.0% at 24 and 48 hours, respectively, compared with baseline. The RSI improved by 10.7 ± 2.1% only at 24 hours. The RFD increased at all time windows at 24 hours (range of improvement: 9.7 ± 3.4% to 18.3 ± 4.1%, p < 0.01). However, at 48 hours, improvement was only seen in RFD0–100 (9.8 ± 3.1%, p < 0.01). These findings suggest that a low-volume, power-type training session results in delayed enhancement of explosive muscle performance, which is greatest at 24 hours after the activity. Athletes are advised to perform power-type training 1 day before competition or a high-quality training session to improve their performances.
Effect of Barbell Weight on the Structure of the Flat Bench Press
Authors: Król Henryk , Gołaś Artur
Published: February 2017

Król, H and Gołaś, A. Effect of barbell weight on the structure of the flat bench press. J Strength Cond Res 31(5): 1321–1337, 2017—In this study, we have used the multimodular measuring system SMART. The system consisted of 6 infrared cameras and a wireless module to measure muscle bioelectric activity. In addition, the path of the barbell was measured with a special device called the pantograph. Our study concerns the change in the structure of the flat bench press when the weight of the barbell is increased. The research on the bench press technique included both the causes of the motion: the internal structure of the movement and the external kinematic structure showing the effects of the motion, i.e., all the characteristics of the movement. Twenty healthy, male recreational weight trainers with at least 1 year of lifting experience (the mean ± SD = 3.3 ± 1.6 years) were recruited for this study. The subjects had a mean body mass of 80.2 ± 8.6 kg, an average height of 1.77 ± 0.08 m, and their average age was 24.7 ± 0.9 years. In the measuring session, the participants performed consecutive sets of a single repetition of bench pressing with an increasing load (about 70, 80, 90, and 100% of their 1 repetition maximum [1RM]). The results showed a significant change in the phase structure of the bench press, as the barbell weight was increased. While doing the bench press at a 100% 1RM load, the pectoralis major changes from being the prime mover to being the supportive prime mover. At the same time, the role of the prime mover is taken on by the deltoideus anterior. The triceps brachii, in particular, clearly shows a greater involvement.
Different Training Loads Partially Influence Physiological Responses to the Preparation Period in Basketball
Authors: Ferioli Davide , Bosio Andrea , La Torre Antonio , Carlomagno Domenico , Connolly Darragh R. , Rampinini Ermanno
Published: February 2017

Ferioli, D, Bosio, A, La Torre, A, Carlomagno, D, Connolly, DR, and Rampinini, E. Different training loads partially influence physiological responses to preparation period in basketball. J Strength Cond Res 32(3): 790–797, 2018—The aim of this study was to compare the session rating of perceived exertion training load (sRPE-TL), training volume (TV), and the changes in physical fitness between professional (n = 14) and semiprofessional (n = 18) basketball players during the preparation period. Furthermore, relationships between sRPE-TL and TV with changes in physical fitness level were investigated. The players performed the Yo-Yo intermittent recovery test—level 1 (Yo-Yo IR1) before and after the preparation period. In addition, physiological responses to a standardized 6-minute continuous running test (Mognoni's test) and to a standardized 5-minute high-intensity intermittent running test (HIT) were measured. Session rating of perceived exertion–TL and TV were greater for professional (5,241 ± 1787 AU; 914 ± 122 minutes) compared with semiprofessional players (2,408 ± 487 AU; 583 ± 65 minutes). Despite these differences, Yo-Yo IR1 performance improvements (∼30%) and physiological adaptations to the Mognoni's test were similar between the 2 groups. Furthermore, physiological adaptations to HIT were slightly greater for professional compared with semiprofessional players; however, the magnitude of these effects was only small/moderate. No clear relationships were found between sRPE-TL and changes in Yo-Yo IR1 performance and Mognoni's test (r
s ± 90% confidence interval [CI]: Yo-Yo IR1, 0.18 ± 0.30; Mognoni's test, −0.14 ± 0.29). Only moderate relationships were found between sRPE-TL and changes in HIT (r
s ± 90% CI: [La−], −0.48 ± 0.23; [H+], −0.42 ± 0.25). These results raise doubts on the effectiveness of using high sRPE-TL and TV during the preparation period to improve the physical fitness level of players. The Yo-Yo IR1 seems to be sensitive to monitor changes induced by the preparation period; however, its use is not recommended to discriminate between adult basketball players of different competitive level.
Acute Effects of Eccentric Overload on Concentric Front Squat Performance
Authors: Munger Cameron N. , Archer David C. , Leyva Whitney D. , Wong Megan A. , Coburn Jared W. , Costa Pablo B. , Brown Lee E.
Published: February 2017

Munger, CN, Archer, DC, Leyva, WD, Wong, MA, Coburn, JW, Costa, PB, and Brown, LE. Acute effects of eccentric overload on concentric front squat performance. J Strength Cond Res 31(5): 1192–1197, 2017—Eccentric overload is used to enhance performance. The purpose of this study was to investigate the acute effects of eccentric overload on concentric front squat performance. Twenty resistance-trained men (age = 23.80 ± 1.82 years, height = 176.95 ± 5.21 cm, mass = 83.49 ± 10.43 kg, 1 repetition maximum [1RM] front squat = 131.02 ± 21.32 kg) volunteered. A dynamic warm-up and warm-up sets of front squat were performed. Eccentric hooks were added to the barbell. They descended for 3 seconds, until eccentric hooks released, and performed the concentric phase as fast as possible. There were 3 randomly ordered conditions with the concentric phase always at 90% 1RM and the eccentric phase at 105, 110, and 120% of 1RM. Two repetitions were performed for each condition. A repeated measures analysis of variance was used to determine differences. For peak velocity, there were main effects for time and condition (p < 0.05), where post (1.01 ± 0.10 m·s−1) was greater than pre (0.96 ± 0.11 m·s−1) and 120% (1.03 ± 1.11 m·s−1) was greater than 105% (0.99 ± 0.13 m·s−1). For peak power, there was a main effect for condition where 120% (2,225.00 ± 432.37 W) was greater than 105% (2,021.84 ± 563.53 W). For peak ground reaction force, there were main effects for time and condition, where post was greater than pre and 120% was greater than 105%. For the rate of force development, there was no interaction or main effects. Eccentric overload enhanced concentric velocity and power; therefore, it can be used by strength coaches and athletes during the power phase of a training program. It can also be used to prescribe supramaximal loads and could be a tool to supplement the clean exercise because the front squat is a precursor.
Relationship Between Training Load, Fitness, and Injury Over an Australian Rules Football Preseason
Authors: Harrison Peter W. , Johnston Rich D.
Published: February 2017

Harrison, PW and Johnston, RD. Relationship between training load, fitness, and injury over an Australian rules football preseason. J Strength Cond Res 31(10): 2686–2693, 2017—Recent research identifies that certain training load (TL) patterns increase the injury risk to athletes. However, physical fitness must also be considered to establish optimal TL patterns. The aim of this study was to identify TL patterns optimal for injury and aerobic fitness by exploring the TL-injury and TL-fitness relationship concurrently over an Australian rules football (ARF) preseason. Individual TL, aerobic fitness, and injury data were collected over a 14-week preseason in 60 subelite ARF players (age = 21.3 ± 2.9 years). Individual TL, assessed through session rating of perceived exertion (sRPE), was compared with noncontact, lower limb soft tissue injury to examine the TL-injury relationship. A 2-km time trial was used as the measure of aerobic fitness to examine the optimal TL for aerobic fitness improvement. Aerobic fitness improved by 4.10 ± 2.20% (range = −7.35–19.05%) over the preseason. Training load between 1,600 and 2,000 AU per week was associated with the greatest aerobic fitness improvement (effect size [ES] = 0.47–1.01). Players with preseason TL <1,250 AU per week had the highest injury rate (ES = 0.52–0.62). Large 2-week TL (>4,000 AU, odds ratio [OR] = 2.80) and spikes in weekly TL (15–49%, OR = 3.76) significantly increased injury risk the following week. Performing small amounts of training seems to be the most detrimental to changes in aerobic fitness and injury rate. High TL is not responsible for injuries and is required to maximize improvements in aerobic fitness. However, TL exceeding 2,000 AU over several weeks may attenuate aerobic fitness improvements and increase injury risk. In addition, large increments in weekly TL increase injury risk.
Heat Exposure and Hypohydration Exacerbate Physiological Strain During Load Carrying
Authors: Adams Elizabeth L. , Casa Douglas J. , Huggins Robert A. , DeMartini-Nolan Julie K. , Stearns Rebecca L. , Kennedy Rachel M. , Bosworth Megan M. , DiStefano Lindsay J. , Armstrong Lawrence E. , Maresh Carl M.
Published: February 2017

Adams, EL, Casa, DJ, Huggins, RA, DeMartini-Nolan, JK, Stearns, RL, Kennedy, RM, Bosworth, MM, DiStefano, LJ, Armstrong, LE, and Maresh, CM. Heat exposure and hypohydration exacerbate physiological strain during load carrying. J Strength Cond Res 33(3): 727–735, 2019—Heat exposure and hypohydration induce physiological and psychological strain during exercise; however, it is unknown if the separate effects of heat exposure and hypohydration are synergistic when co-occurring during loaded exercise. This study compared separate and combined effects of heat exposure and hypohydration on physiological strain, mood state, and visual vigilance during loaded exercise. Twelve men (mean ± SD; age, 20 ± 2 years; body mass, 74.0 ± 8.2 kg; maximal oxygen uptake, 57.0 ± 6.0 ml·kg−1·min−1) completed 4 trials under the following conditions: euhydrated temperate (EUT), hypohydrated temperate (HYT), euhydrated hot (EUH), and hypohydrated hot (HYH). Exercise was 90 minutes of treadmill walking (∼50% V̇o
2max, 5% grade) while carrying a 45-lb rucksack. Profile of Mood States and the Scanning Visual Vigilance Test were completed before and after exercise. The separate effects of heat exposure (EUH) and hypohydration (HYT) on post-exercise rectal temperature (Tre) were similar (38.25 ± 0.63°C vs. 38.22 ± 0.29°C, respectively, p > 0.05), whereas in combination (HYH), post-exercise Tre was far greater (39.32 ± 0.43°C). Increase in Tre per 1% body mass loss (BML) for HYH (vs. EUH) was greater than HYT (vs. EUT) (0.32 vs. 0.04°C, respectively, p = 0.02); heart rate increase per 1% BML for HYH (vs. EUH) was 7 b·min−1 compared with HYT (vs. EUT) at 3 b·min−1 (p = 0.30). Hypohydrated hot induced greater mood disturbance (post-exercise ‐ pre-exercise) (35 ± 21 units) compared with other conditions (EUT = 3 ± 9 units; HYT = 3 ± 16 units; EUH = 16 ± 26 units; p < 0.001). No differences occurred in visual vigilance (p > 0.05). Independently, heat exposure and hypohydration induced similar physiological strain during loaded exercise; when combined, heat exposure with hypohydration, synergistically exacerbated physiological strain and mood disturbance.
Evaluating Upper-Body Strength and Power From a Single Test: The Ballistic Push-up
Authors: Wang Ran , Hoffman Jay R. , Sadres Eliahu , Bartolomei Sandro , Muddle Tyler W.D. , Fukuda David H. , Stout Jeffrey R.
Published: February 2017

Wang, R, Hoffman, JR, Sadres, E, Bartolomei, S, Muddle, TWD, Fukuda, DH, and Stout, JR. Evaluating upper-body strength and power from a single test: the ballistic push-up. J Strength Cond Res 31(5): 1338–1345, 2017—The purpose of this study was to examine the reliability of the ballistic push-up (BPU) exercise and to develop a prediction model for both maximal strength (1 repetition maximum [1RM]) in the bench press exercise and upper-body power. Sixty recreationally active men completed a 1RM bench press and 2 BPU assessments in 3 separate testing sessions. Peak and mean force, peak and mean rate of force development, net impulse, peak velocity, flight time, and peak and mean power were determined. Intraclass correlation coefficients were used to examine the reliability of the BPU. Stepwise linear regression was used to develop 1RM bench press and power prediction equations. Intraclass correlation coefficient's ranged from 0.849 to 0.971 for the BPU measurements. Multiple regression analysis provided the following 1RM bench press prediction equation: 1RM = 0.31 × Mean Force − 1.64 × Body Mass + 0.70 (R
2 = 0.837, standard error of the estimate [SEE] = 11 kg); time-based power prediction equation: Peak Power = 11.0 × Body Mass + 2012.3 × Flight Time − 338.0 (R
2 = 0.658, SEE = 150 W), Mean Power = 6.7 × Body Mass + 1004.4 × Flight Time − 224.6 (R
2 = 0.664, SEE = 82 W); and velocity-based power prediction equation: Peak Power = 8.1 × Body Mass + 818.6 × Peak Velocity − 762.0 (R
2 = 0.797, SEE = 115 W); Mean Power = 5.2 × Body Mass + 435.9 × Peak Velocity − 467.7 (R
2 = 0.838, SEE = 57 W). The BPU is a reliable test for both upper-body strength and power. Results indicate that the mean force generated from the BPU can be used to predict 1RM bench press, whereas peak velocity and flight time measured during the BPU can be used to predict upper-body power. These findings support the potential use of the BPU as a valid method to evaluate upper-body strength and power.
The High-Bar and Low-Bar Back-Squats: A Biomechanical Analysis
Authors: Glassbrook Daniel J. , Brown Scott R. , Helms Eric R. , Duncan Scott , Storey Adam G.
Published: February 2017

Glassbrook, DJ, Brown, SR, Helms, ER, Duncan, S, and Storey, AG. The high-bar and low-bar back-squats: a biomechanical analysis. J Strength Cond Res 33(7S): S1–S18, 2019—No previous study has compared the joint angle and ground reaction force (vertical force [Fv]) differences between the high-bar back-squat (HBBS) and low-bar back-squat (LBBS) above 90% 1 repetition maximum (1RM). Six male powerlifters (POW) (height: 179.2 ± 7.8 cm; mass: 87.1 ± 8.0 kg; age: 21–33 years) of international level, 6 male Olympic weightlifters (OLY) (height: 176.7 ± 7.7 cm; mass: 83.1 ± 13 kg; age: 22–30 years) of national level, and 6 recreationally trained male athletes (height: 181.9 ± 8.7 cm; mass: 87.9 ± 15.3 kg; age: 23–33 years) performed the LBBS, HBBS, and both LBBS and HBBS (respectively) up to and including 100% 1RM. Small to moderate (d = 0.2–0.5) effect size differences were observed between the POW and OLY in joint angles and Fv, although none were statistically significant. However, significant joint angle results were observed between the experienced POW/OLY and the recreationally trained group. Our findings suggest that practitioners seeking to place emphasis on the stronger hip musculature should consider the LBBS. Also, when the goal is to lift the greatest load possible, the LBBS may be preferable. Conversely, the HBBS is more suited to replicate movements that exhibit a more upright torso position, such as the snatch and clean, or to place more emphasis on the associated musculature of the knee joint.
Reduction of Physiological Strain Under a Hot and Humid Environment by a Hybrid Cooling Vest
Authors: Chan Albert P.C. , Yang Yang , Wong Francis K.W. , Yam Michael C.H. , Wong Del P. , Song Wen-Fang
Published: February 2017

Chan, APC, Yang, Y, Wong, FKW, Yam, MCH, Wong, DP, and Song, W-F. Reduction of physiological strain under a hot and humid environment by a hybrid cooling vest. J Strength Cond Res 33(5): 1429–1436, 2019—Cooling treatment is regarded as one of good practices to provide safe training conditions to athletic trainers in the hot environment. The present study aimed to investigate whether wearing a commercial lightweight and portable hybrid cooling vest that combines air ventilation fans with frozen gel packs was an effective means to reduce participants' body heat strain. In this within-subject repeated measures study, 10 male volunteers participated in 2 heat-stress trials (one with the cooling vest—COOL condition, and another without—CON condition, in a randomized order) inside a climatic chamber with a controlled ambient temperature 33° C and relative humidity (RH) 75% on an experimental day. Each trial included a progressively incremental running test, followed by a 40-minute postexercise recovery. Core temperature (Tc), heart rate (HR), sweat rate (SR), rating of perceived exertion (RPE), exercise duration, running distance, and power output were measured. When comparing the 2 conditions, a nonstatistically significant moderate cooling effect in rate of increase in Tc (0.03 ± 0.02° C·min−1 for COOL vs. 0.04 ± 0.02° C·min−1 for CON, p = 0.054, d = 0.57), HR (3 ± 1 b·min–1·min−1 for COOL vs. 4 ± 1 b·min–1·min−1 for CON, p = 0.229, d = 0.40), and physiological strain index (PSI) (0.20 ± 0.06 unit·min−1 for COOL vs. 0.23 ± 0.06 unit·min−1 for CON, p = 0.072, d = 0.50) was found in the COOL condition during exercise. A nonstatistically significant (p > 0.05) trivial cooling effect (d < 0.2) was observed between the COOL and CON conditions for measures of exercise duration, running distance, power output, SR, and RPE. It is concluded that the use of the hybrid cooling vest achieved a moderate cooling effect in lowering the rate of increase in physiological strain without impeding the performance of progressively incremental exercise in the heat.
Repetition Performance and Blood Lactate Responses Adopting Different Recovery Periods Between Training Sessions in Trained Men
Authors: Miranda Humberto , Maia Marianna F. , Paz Gabriel A. , de Souza João A.A.A. , Simão Roberto , Farias Déborah A. , Willardson Jeffrey M.
Published: February 2017

Miranda, H, Maia, MF, Paz, GA, de Souza, JAAA, Simão, R, Farias, DA, and Willardson, JM. Repetition performance and blood lactate responses adopting different recovery periods between training sessions in trained men. J Strength Cond Res 32(12): 3340–3347, 2018—The purpose of this study was to examine the effect of different recovery periods (24, 48, and 72 hours) between repeated resistance training (RT) sessions for the upper-body muscles on repetition performance and blood lactate responses in trained men. Sixteen recreationally trained men (age: 26.1 ± 3.1 years; height: 179 ± 4.5 cm; body mass: 82.6 ± 4.0 kg, 4.5 ± 2.2 years of RT experience) participated in this study. Eight repetition maximum (8RM) loads were determined for the bench press (BP), 30° incline bench press (BP30), and 45° incline bench press (BP45) exercises. To assess the effects of different recovery periods between repeated training sessions, 3 protocols were performed in randomized order, including 24 hours (P24), 48 hours (P48), and 72 hours (P72). Each RT session consisted of performing 4 repetition maximum sets of the BP, BP30, and BP45 with 8RM loads and 2-minute rest intervals between sets. Blood lactate levels were measured presession (PRE), immediately postsession (POST), 3 minutes postsession (P3), and 5 minutes postsession (P5). For the P24 protocol, significant decreases in repetition performance were found between sessions for the BP, BP30, and BP45 exercises, respectively. When considering session 2 only, the total work (repetition × sets) was significantly higher under P48 and P72 compared with P24 for the BP30 and BP45 exercises. Blood lactate levels (i.e., POST, P3, and P5) significantly increased for session 2 under the P24 compared with the P48 and P72 protocols, respectively. Therefore, coaches and practitioners who need to accomplish a higher training volume for the upper-body muscles should adopt recovery periods longer than 24 hours between sessions that train the same or similar muscle groups.
Effects of Fat Grip Training on Muscular Strength and Driving Performance in Division I Male Golfers
Authors: Cummings Patrick M. , Waldman Hunter S. , Krings Ben M. , Smith JohnEric W. , McAllister Matthew J.
Published: February 2017

Cummings, PM, Waldman, HS, Krings, BM, Smith, JW, and McAllister, MJ. Effects of fat grip training on muscular strength and driving performance in division I male golfers. J Strength Cond Res 32(1): 205–210, 2018—Fat grip (FG) training is implemented into strength and conditioning programs with the overall goal of increasing grip strength. Previous research assessing the effect of training with increased grip diameters compared with standard Olympic bar diameters has mainly been in acute settings. Therefore, the purpose of this study was to examine to effects FG training compared with normal diameter grip (CON) training during an 8-week periodized resistance training (RT) program in division I male golfers. Subjects (n = 10) were randomly assigned into 2 groups: the FG group (n = 5, scoring average: 75.4 ± 2.0) and CON group (n = 5, scoring average: 75.0 ± 0.5). Both groups participated in 8 weeks of RT (3 d·wk−1). The FG group completed every lift and repetition using FG, compared with the CON training group which used normal diameter bars. Pretraining and posttraining performance variables included swing speed, ball speed, driving distance, driving carry, maximum pull-ups to failure, right and left hand grip strength, and 1 repetition max trap-bar deadlift. The FG group demonstrated significant increases (p ≤ 0.05) in ball speed, carry, drive distance, and left hand grip strength after 8 weeks of RT. In a population, such as low-handicap division I male golfers, FG training may allow for athletes to increase golf-specific performance after 8 weeks of periodized RT. Strength and conditioning coaches may use FG training over the course of a training program with athletes who require adequate grip strength to further elicit training adaptations.
Prognostic significance of diffuse sclerosing variant papillary thyroid carcinoma: a systematic review and meta-analysis
Authors: Vuong Huy Gia , Kondo Tetsuo , Pham Thong Quang , Oishi Naoki , Mochizuki Kunio , Nakazawa Tadao , Hassell Lewis , Katoh Ryohei
Published: February 2017

Objective

Diffuse sclerosing variant papillary thyroid carcinoma (DSVPTC) is an uncommon variant of papillary thyroid carcinoma (PTC). The biological behaviors and prognostic outcomes of this variant, however, are still controversial. The aim of this systematic review and meta-analysis is to investigate the prognostic significance and outcomes of DSVPTCs in comparison with classical PTCs (cPTCs).

Methods

An electronic search was performed in five libraries: PubMed, Scopus, ISI, World Health Organization Global Health Library (WHO GHL) and Virtual Health Library (VHL) in June 2016. Published data were extracted and were pooled into odds ratios (OR), mean differences and corresponding 95% confidence intervals (CI) using random-effect model. Publication bias was analyzed using Egger’s regression test and funnel plot observation.

Results

From 315 articles, we included 16 articles comprising 732 DSVPTCs for meta-analysis. Overall, DSVPTC manifested more aggressive clinicopathological behaviors than cPTC such as higher rate of vascular invasion (OR: 5.33; 95% CI: 3.08–9.23), extrathyroidal extension (OR: 2.96; 95% CI: 2.04–4.30), lymph node metastasis (OR: 5.40; 95% CI: 2.82–10.35), distant metastasis (OR: 3.61; 95% CI: 1.89–6.88) and were more likely to relapse (OR: 2.83; 95% CI: 1.59–5.05). DSVPTC patients were associated with a worsened overall survival (HR: 1.89; 95% CI: 1.36–2.62).

Conclusion

DSVPTCs should be considered high-risk PTCs because of high propensity for tumor invasion, metastasis, relapse and mortality. Aggressiveness of DSVPTCs might be related to a different molecular pathway than that in cPTCs.
IGFBP-4 regulates adult skeletal growth in a sex-specific manner
Authors: Maridas David E , DeMambro Victoria E , Le Phuong T , Nagano Kenichi , Baron Roland , Mohan Subburaman , Rosen Clifford J
Published: February 2017

Insulin-like growth factor-1 (IGF-1) and its binding proteins are critical mediators of skeletal growth. Insulin-like growth factor-binding protein 4 (IGFBP-4) is highly expressed in osteoblasts and inhibits IGF-1 actions in vitro. Yet, in vivo studies suggest that it could potentiate IGF-1 and IGF-2 actions. In this study, we hypothesized that IGFBP-4 might potentiate the actions of IGF-1 on the skeleton. To test this, we comprehensively studied 8- and 16-week-old Igfbp4−/− mice. Both male and female adult Igfbp4−/− mice had marked growth retardation with reductions in body weight, body and femur lengths, fat proportion and lean mass at 8 and 16 weeks. Marked reductions in aBMD and aBMC were observed in 16-week-old Igfbp4−/− females, but not in males. Femoral trabecular BV/TV and thickness, cortical fraction and thickness in 16-week-old Igfbp4−/− females were significantly reduced. However, surprisingly, males had significantly more trabeculae with higher connectivity density than controls. Concordantly, histomorphometry revealed higher bone resorption and lower bone formation in Igfbp4−/− females. In contrast, Igfbp4−/− males had lower mineralized surface/bone surface. Femoral expression of Sost and circulating levels of sclerostin were reduced but only in Igfbp4−/− males. Bone marrow stromal cultures from mutants showed increased osteogenesis, whereas osteoclastogenesis was markedly increased in cells from Igfbp4−/− females but decreased in males. In sum, our results indicate that loss of Igfbp4 affects mesenchymal stromal cell differentiation, regulates osteoclastogenesis and influences both skeletal development and adult bone maintenance. Thus, IGFBP-4 modulates the skeleton in a gender-specific manner, acting as both a cell autonomous and cell non-autonomous factor.
Influence of Poisson's ratio uncertainty on calculations of the bowing parameter for strained InGaN layers
Authors: Stepanov S. , Wang W.N. , Yavich B.S. , Bougrov V. , Rebane Y.T. , Shreter Y.G.
Published: February 2017

The composition dependence of emission energy of pseudomorphically strained InGaN layers with In content up to 0.2 is obtained. It is found that the main reason of “scatter” in published values of the InGaN bowing parameter is the uncertainty of the Poisson's ratio determination. It is shown that after recalculation to the same Poisson's ratio, most published data yield essentially the same results as compared to experimental uncertainty.
On the origin of the 2.8 eV blue emission in p-type GaN:Mg : A time-resolved photoluminescence investigation
Authors: Shahedipour F. , Wessels B.W.
Published: February 2017

The decay dynamics of the 2.8 eV emission band in p-type GaN was investigated using time-resolved photoluminescence spectroscopy. The luminescence intensity decays non-exponentially. The decay dynamics were consistent with donor-acceptor pair recombination for a random distribution of pair distances. Calculations using the Thomas-Hopfield model indicated that recombination involves deep donors and shallow acceptors.
Review of Structure of Bare and Adsorbate-Covered GaN(0001) Surfaces
Authors: Feenstra R. M. , Northrup J. E. , Neugebauer Jörg
Published: February 2017

A review of surface structures of bare and adsorbate-covered GaN (0001) and (000) surfaces is presented, including results for In, Mg, Si, and H adsorbates. Emphasis is given to direct determination of surface structure employing experimental techniques such as scanning tunneling microscopy, electron diffraction, and Auger electron spectroscopy, and utilizing first principles computations of the total energy of various structural models. Different surface stoichiometries are studied experimentally by varying the surface preparation conditions (e.g. Ga-rich compared to N-rich), and the stoichiometry is included in the theory by performing calculations for various chemical potentials of the constituent atoms. Based on the work reviewed here, surface reconstructions for plasma-assisted molecular beam epitaxy growth of GaN (0001) and (000) surfaces are fairly well understood, but reconstructions for reactive molecular beam epitaxy or for metal-organic vapor phase epitaxy (both involving H, at moderate and high temperatures, respectively) are less well understood at present.
Hardness of bulk single-crystal GaN and AlN
Authors: Yonenaga Ichiro
Published: February 2017

The hardness of single-crystal GaN and AlN of 0.5-mm-thickness was measured by the Vickers indentation method in the temperature range 20 - 1400°C. The hardness of GaN and AlN is 10.2 and 17.7 GPa, respectively, at room temperature. The nano-indentation hardness of single-crystal AlN was measured at room temperature as 18 GPa, harder than GaN and InN. Up to about 1100°C, GaN and AlN maintain its hardness similar to that of SiC and thus, a high mechanical stability for GaN and AlN at elevated temperatures is deduced. Yield strength of nitrides is discussed.
High-Performance Solar-Blind AlGaN Schottky Photodiodes
Authors: Biyikli Necmi , Kartaloglu Tolga , Aytur Orhan , Kimukin Ibrahim , Ozbay Ekmel
Published: February 2017

High-performance solar-blind AlGaN-based Schottky photodiodes have been demonstrated. The detectors were fabricated on MOCVD-grown AlGaN/GaN hetero-structures using a microwave-compatible fabrication process. Current-voltage, spectral responsivity, noise, and high-speed characteristics of the detectors were measured and analyzed. Dark currents lower than 1 pA at bias voltages as high as 30 V were obtained. True solar-blind detection was achieved with a cut-off wavelength lower than 266 nm. A peak device responsivity of 78 mA/W at 250 nm was measured under 15 V reverse bias. A visible rejection of more than 4 orders of magnitude was observed. The solar-blind photodiodes exhibited noise densities below the measurement setup noise floor of 3×10−29 A2/Hz around 10 KHz. High-speed measurements at the solar-blind wavelength of 267 nm resulted in 3-dB bandwidths as high as 870 MHz.
Growth of Semi-insulating GaN Layer by Controlling Size of Nucleation Sites for SAW Device Applications
Authors: Lee Jae-Hoon , Lee Myoung-Bok , Hahm Sung-Ho , Lee Yong-Hyun , Lee Jung-Hee , Young-HoBa  , Cho Hyun Kyung
Published: February 2017

Semi-insulating undoped GaN films were grown based on controlling the size of the nucleation sites through a special two-step growth method: First, 16 nm LT-GaN was annealed at 950 ° with a ramping time of 4 min, then the GaN was grown at this temperature for 1 min. Second, the growth temperature was increased to 1020° with a ramping time of 2 min and the GaN layer finally grown at 1020 ° for 40 min. The film grown by this sequence exhibited sheet resistance of up to 109 Ω/sq with mirror-like surface morphology. By slow ramping to 950° in the initial phase of growth, smaller grain sizes and higher nuclei densities were formed and the columnar growth mode along the c direction was dominant. The observation of higher resistance in two-step growth is believed due to the increased misorientation of nuclei when the growth proceeds during temperature ramping to 1020°. The fabricated saw filter on semi-insulating GaN exhibited a high velocity of 5342 m/s at center frequencies of 133.57 MHz and an electromechanical coupling coefficient(k2) of about 0.763 %, which was enhanced due to the improvement of surface morphology with high sheet resistance by the two- step ramping technique.
P- and N-type Doping of Non-Polar A-plane GaN Grown by Molecular-Beam Epitaxy on R-plane Sapphire
Authors: Armitage R. , Yang Qing , Weber Eicke R.
Published: February 2017

Non-polar a-plane GaN films doped with Si or Mg were grown by plasma-assisted molecular-beam epitaxy on r-plane sapphire substrates. The (110) orientation of the GaN epilayers was confirmed by x-ray diffraction. The layers were further characterized by atomic force microscopy, Hall effect, and photoluminescence measurements. The Mg-doped layers showed p-type conductivity, with a maximum hole concentration of 6×1017 cm−3 (μ = 2 cm2/Vs). Comparison with Mg-doping of N-polar c-plane GaN suggests the Mg sticking coefficient may be higher on the GaN (110) surface compared to the GaN (000) surface. The electron mobility obtained for a-plane GaN:Si (18 cm2/Vs for n = 1×1018 cm−3) was low compared to that of typical c-plane epilayers. The lower electron mobility is attributed to the higher density of structural defects in a-plane GaN.
PENGARUH INTENSITAS CAHAYA TERHADAP KETERTARIKAN GEROMBOLAN IKAN PELAGIS KECIL PADA MINI PURSE SEINE DI PERAIRAN PEMALANG JAWA TENGAH
Authors: Nurdin Erfind , Natsir Mohammad , Hufiadi Hufiadi
Published: February 2017

Penggunaan intensitas cahaya pada unit penangkapan light fishing cenderung meningkat. Hal ini, didasari atas persepsi bahwa intensitas cahaya yang tinggi akan meningkatkan hasil tangkapan. Fenomena ini dijadikan suatu penelitian yang dilakukan selama 3 minggu pada bulan September 2004 di perairan Pemalang Jawa Tengah. Alat tangkap pukat cincin mini (mini purse seine) di pantai utara Jawa pada operasi penangkapan selain menggunakan rumpon juga mengggunakan cahaya sebagai alat bantu penangkapan. Pengukuran nilai intensitas lampu dilakukan dengan meggunakan LI COR 250 quantum meter (μmol sÉ¹ mÉ²) pada jumlah lampu yang berbeda, dan digunakan pula akustik EY 500 untuk memperoleh data sebaran dan gerombolan ikan yang berada dalam pengaruh cahaya lampu. Pada deteksi awal (A) ikan cenderung mengelompok pada lahan intensitas tinggi, deteksi ke 2 (B) pengelompokkan mulai terkonsentrasi dekat kapal, deteksi ke-3 (C) pengelompokkan ikan bertambah banyak, dan deteksi ke-4 (D) kelompok ikan berada pada lahan yang sangat memungkinkan untuk ditangkap. Dari hasil penelitian diperoleh laju tangkap (catch rate) 125,7 kg per tawur. Perbedaan jumlah lampu yang sedikit tidak menunjukkan pengaruh yang terlalu besar terhadap hasil tangkapan. The influence of light intensity to the light fishing practices commonly tends to increase. Fishermen believe that with the higher intensity of light the bigger catch they have. This phenomenon stimulated us to a research that during was done three weeks on September 2004 in Pemalang West Java. Mini purse seine is conduct at north coast of Java use payaos and light artificial for fish attractive. LI COR 250 quantum metre (μmol sÉ¹ mÉ²) was used for light intencity at different lamps amount and EY 500 acoustic to obtain the data of fish school in influence of lamp light. At the first detecting (A) fish school was concentrated in high intensity area, the second detecting (B) the concentration was closer to the ship, the third detecting (C) fish school increased, and the forth detecting (D) fish school was consentrated in catchable area. The results show that the cath rate was 125.7 kg per setting. The difference of lamps amount with a small intensity did not show significant influence to the catch haul.
Understanding the revolutionary character of L2 development in the ZPD
Authors: Lantolf James P. , Kurtz Lindsey , Kisselev Olesya
Published: February 2017

The Zone of Proximal Development has been one of the most misunderstood features of Sociocultural Theory. It has been inappropriately equated with Krashen’s i+1 and with the concept of ‘scaffolding’. Based on an empirical study where learners seemed to require the same degree of explicit mediation at two different points in time, Erlam, et al. (2013) have questioned Aljaafreh and Lantolf’s (1994) regulatory scale and have instead supported a one-size-fits-all use of explicit mediation. This article provides a theoretical and empirical counter argument to Erlam, et al.’s (2013) proposal. Given Vygotsky’s (1987) claim that development is revolutionary, on theoretical grounds alone, we would not expect that because at time 1 a learner required explicit mediation at time 2 that same learner would require less explicit (or more implicit) mediation to recognize and correct use of an inappropriate L2 feature. We also present empirical evidence from a close analysis of Aljaafreh’s (1992) dissertation that supplements the data considered in Lantolf and Aljaafreh (1995), which showed that even when mediation regresses from more implicit to more explicit levels on the regulatory scale, it does not regress to the beginning of the process where mediation is maximally explicit. Progress, overall, is forward, even if it requires some backtracking.
Gender and Assigned Role Influences Medical Students´ Learning Experience in Interprofessional Team Training Simulations
Authors: Tamás Éva , Edelbring Samuel , Hjelm Carina , Hult Håkan , Gimm Oliver
Published: February 2017

This article was migrated. The article was marked as recommended. The advantages of providing standardized education avoiding exposure of real patients to interventions by novices are appealing both from patient safety and teaching aspects, thus medical simulation has become an integrated part of the healthcare curriculum.We explored the impact of gender and an acting vs. an observing role in simulation on students' perceptions of learning outcomes, and of simulation as a learning activity.A prospective survey for graduating medical students participating in a full day simulated team training session was conducted over three terms. The questionnaire addressed issues related to the session, teamwork and simulation training in general. Participation was voluntary and the study was approved by the regional ethics committee.The overall response rate was 90.8 %. Authenticity and relevance were considered to be high, though male students scored significantly higher both for authenticity and for relevance. Communication and teamwork were considered to be different, depending on gender and assigned role. Female students and students in an acting role were more ready to discuss knowledge gaps, experienced "good" communication significantly more often, and defined their work as teamwork more frequently. The scenarios were found to be more stimulating and motivating by female students and acting individuals. Self-confidence and self-awareness were declared to be more enhanced for male students and for those who were acting during the simulation sessions. Observers and female students scored significantly lower as regards satisfaction with both the extent of the reflection and the individual feedback.The perceptions of authenticity and relevance of simulation sessions and students' readiness to discuss knowledge gaps differed between genders. Furthermore, perceived changes in self-confidence and self-awareness seemed to be different. The observing role implies a different kind of learning process, which is not necessarily inferior to learning by acting.