bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the properties of Permanent Cold Patching (PCP)
Authors: Thanaya, ME., PhD I Nyoman Arya , Jayantara I Wayan Putra , Purbanto I Gusti Raka
Published: August 2020

Patching road pothole can be done using Permanent Cold Patching (PCP). This research main aim was to analyze the characteristic of the PCP. PCP Super Cold Mix Asphalt was used for the experiment. The mixtures were compacted Marshall hummer in lab using, and plate compactor on site. It was obtained that: compaction temperature variation significantly affected the characteristic of the mixture. Compaction at 100°C and 150°C, met stability, porosity and VMA specification, but not for the VFB. It required more compaction energy. The stability of cold compacted mixture at the age of 1 hour gave 844.74 kg (min. 500 kg). Towards this value, at the age of 48 hours; 96 hours; 192 hours; 384 hours, respectively gave increase of stability of 102%; 140%; 183%; 187% and then constant. Cold compaction on site gave less performance with porosity values in a range of 4.585-8.22% (spec. 4% -10%), therefore the VFB is less than minimum 65% of VMA; the stability obtained was 1422.72 kg (>min 500kg) or 58% stability of the samples compacted in lab at the same 16 days of age where stability had become maximum (constant). Cantabro test result of the cold mix gave 100% weight loss (the sample disintegrated), meanwhile the hot mix only lost 7.56% from 16% max loss.
Activity of Alkaline Phosphatase in the Major Salivary Glands of Mice at Various Ages of Postnatal Life, and During Pregnancy and Lactation
Authors: Pospíšilová Blanka , Slížová Dáša , Procházková Olga , Krs Otakar , Bílek Petr
Published: August 2020

Activity of alkaline phosphatase in the major salivary glands of male and female mice at various ages of postnatal life, and in females during pregnancy and lactation was studied histochemically. Enzyme activity was not detected on the day of birth, but was found in the terminal tubules of all major salivary glands during the first postnatal week. Alkaline phosphatase activity was increasing gradually with age and a definitive enzymatic pattern was observed by the age of 6 weeks. No difference in enzyme activity was found among the major salivary glands of young adult and old animals. The parenchyma of fully differentiated submandibular glands showed clear sexually dimorphic patterns of alkaline phosphatase activity. During pregnancy, a significant increase of alkaline phosphatase activity was detected in submandibular gland. From gestation day 15 to the end of pregnancy, enzymic pattern of granular convoluted tubules of pregnant females was the same as in the adult males. Histochemical masculinization of the submandibular gland during pregnancy suggests that besides androgens also progesterone exerts masculinization of the murine submandibular salivary gland.
Hypocholesterolemic Effect of Pravastatin is Associated with Increased Content of Antioxidant Vitamin-E in Cholesterol Fractions
Authors: Bláha Vladimír , Zadák Zdeněk , Solichová Dagmar , Brátová Miluše , Havel Eduard
Published: August 2020

Metabolic studies support the findings that antioxidants inhibit atherosclerosis. Treatment with vitamin E reduced both the susceptibility of low density lipoprotein cholesterol (LDL-C) to in vivo lipid peroxidation and atherosclerosis and smooth muscle proliferation. Thus the aim of present study was to examine metabolic consequences of reduced plasma LDL-C during hypolipidemic therapy and the distribution of antioxidant vitamin E. A group of 10 patients (4 men, 6 women, age 35 - 65y) with familial hypercholesterolaemia was treated using pravastatin (Lipostat® Bristol Myers Squibb, 40mg daily at 6.00 PM). Blood samples were examined before treatment, after 4 and 8 weeks of therapy. After ultracentrifugation, samples were analyzed for lipoprotein fractions and the content of vitamin E and cholesterol. Pravastatin reduced both total cholesterol (9.85±0.74 vs. 6.81±0.51 mmol/l; p<0.01), LDL-C (6.42±0.45 vs. 4.51±0.45 mmol/l; p<0.01), light LDL1-C (4.56±0.50 vs. 3.11±0.34 mmol/l; p<0.05) and dense LDL2-C (1.86±0.27 vs. 1.42±0.17 mmol/l; ns). Serum vitamin E was reduced during hypolipidemic therapy in the fraction of total, LDL1, LDL2 and VLDL-cholesterol. However, the ratio of serum vitamin E/total serum cholesterol (4.57±0.32 vs. 5.12±0.37 mmol/l/mmol/l; p<0.05) and ratio of LDL2-C vitamin E/LDL2-C (3.92±0.07 vs. 4.64±0.37 mmol/l/mmol/l; p=0.08) increased in comparison to pre-treatment values. We conclude that pravastatin therapy may possess anti-atherogenic properties which involve not only its hypocholesterolemic effect, but also its favorable effects on the distribution of LDL subclasses and the content of antioxidant vitamin E in atherogenic lipoproteins.
Psychometric properties of the UWES-9S in Peruvian college students
Authors: Dominguez-Lara Sergio Alexis , Sánchez-Villena Andy Rick , Fernández-Arata Manuel
Published: August 2020

The objective of this study was to evaluate the internal structure dimensionality of the Utrech Work Engagement Scale – Student (UWES–9S) and its association with the academic procrastination reported by 321 psychology students from a private university in Cajamarca (Peru) ranging between 17 and 41 years old (79% women; Mage = 22.50 years; 84% between 17 and 25 years old). The UWES-9S and the Academic Procrastination Scale (APS) were used and both a confirmatory and a bifactor analysis were conducted on the UWES–9S, as well as a structural regression analysis that specified the influence of the general and specific dimensions of engagement on the dimensions of academic procrastination. Regarding the results, the bifactor model is the one that best defines the construct, whereas the general dimension of engagement has a greater influence on the dimensions of academic procrastination than the specific ones. The theoretical and practical implications of the findings are discussed, as well as the need to focus on the students’ positive resources in order to achieve greater involvement in their academic work.
Tipo de parto y sensibilidad materna: Efectos en el desarrollo socioemocional de niños y niñas al año de edad
Authors: Ramos Rodrigo , Yávar Verónica , Del Río Alejandro , Schettino Javiera , Bresciani Valentina , Gómez Diana , Álvarez Carolina , Farkas Chamarrita
Published: August 2020

La infancia temprana es un periodo de gran relevancia en el desarrollo socioemocional infantil; de hecho, es donde se sientan las bases del desarrollo futuro. En este sentido, las adquisiciones durante el primer año de vida son predictores importantes de las habilidades sociales y emocionales futuras, de modo que la sensibilidad materna, según evidencia respecto a sus efectos en el desarrollo socioemocional del niño, ha demostrado ser un aspecto fundamental durante este periodo. Teniendo esto en cuenta, y considerando la relevancia de dicha competencia, así como el alza mundial y nacional en las tasas de cesárea y los posibles riesgos asociados al tipo de parto vivenciado, el presente estudio tuvo como objetivo analizar la influencia dela sensibilidad materna y del tipo de parto en el desarrollo socioemocional infantil al año de edad. Para ello, se estudió una muestra no probabilística intencionada de 91 madres con sus respectivos hijos o hijas de distinto nivel socioeconómico que asistían a salas cuna públicas o privadas en la ciudad de Santiago, Chile, por medio de dos instrumentos: la escala de sensibilidad del adulto (ESA) y la functional emotional assessment scale (FEAS). En general, los resultados no mostraron diferencias en el desarrollo socioemocional de los niños según el tipo de parto, aunque sí se pudo apreciar una relación entre una mayor sensibilidad materna y un mayor desarrollo socioemocional de los niños al año de edad. Al final se discuten las implicaciones de promover la sensibilidad materna con el fin de apoyar un óptimo desarrollo socioemocional en los infantes.
Evidence of validity and factorial invariance of the Sternberg Love Scale Brief Spanish Version
Authors: Ventura-León José , Caycho-Rodríguez Tomás , Jara-Avalos Stefani , Yañez Jeaniret , Icochea Kelly , Rodas Nikolai
Published: August 2020

This study aims to adapt, provide evidence of validity, analyze the invariance across gender, and estimate the reliability of the reduced version of the Sternberg's Triangular Love Scale (STLS-R). The sample size comprises 988 Peruvians (748 females and 240 males), who had been in a relationship for at least one month, and whose ages ranged from16 to 54 years old (M=21.29; SD=3.91). Before the statistical analysis, the semantic equivalence was tested through the translation-back translation method. The results indicate that the three-dimensional STLS-R model present satisfactory goodness-of-fit in the data (χ2 (87) = 177.14; χ2/df =2.04; CFI =.99; RMSEA=.03 [.02, .04]; SRMR = .03) which is invariant with respect to gender, and show acceptable reliability regarding intimacy (ω = .91), commitment (ω = .93) and passion (ω = .86). The overall results offer sufficient valid evidence and suggest that the scale can be used in further studies. However, its effectiveness should still be tested in different regions of Peru.
The Effects of 6 Weeks Eccentric Training on Speed, Dynamic Balance, Muscle Strength, Power, and Lower Limb Asymmetry in Prepubescent Weightlifters
Authors: Hammami Raouf , Duncan Michael J. , Nebigh Ammar , Werfelli Hanen , Rebai Haithem
Published: August 2020

Hammami, R, Duncan, MJ, Nebigh, A, Werfelli, H, and Rebai, H. The effects of 6 weeks eccentric training on speed, dynamic balance, muscle strength, power and lower limb asymmetry in prepubescent weightlifters. J Strength Cond Res 36(4): 955–962, 2022—This study examined whether 6 weeks of twice-weekly in-season hamstring eccentric training would enhance selected performance-related abilities in prepubescent male weightlifters. Twenty elite weightlifters (11.1 ± 0.8 years) were randomly split into an eccentric training intervention group (INT n = 10) or a control group (CON) that maintained their standard in-season regimen (n = 10). Pre-intervention and postintervention speed, dynamic balance, muscle strength, power, and lower limb (LL) asymmetry were assessed. Analysis of covariance controlling for maturation was used to determine any differences in the performance variables. There were no significant changes in muscle strength, dynamic balance, or LL asymmetry (all p < 0.05) because of the intervention. Both 10-m (p = 0.001) and 30-m (p = 0.007) sprint speed and agility (p = 0.049) improved to a greater extent in INT compared with the CON group. Similar results were evident for the standing long jump (p = 0.015) and 3 hop test (p = 0.004) where performance improved to a greater magnitude in INT compared with CON groups. This study suggests that eccentric training, undertaken twice weekly for 6-weeks results in positive changes in sprint speed, change of direction speed, and power performance, but not muscle strength, dynamic balance, or LL asymmetry in prepubertal weightlifters.
Sweat Characteristics in Individuals With Varying Susceptibilities of Exercise-Associated Muscle Cramps
Authors: Szymanski Michael , Miller Kevin C. , O'Connor Paul , Hildebrandt Leslie , Umberger Leah
Published: August 2020

Szymanski, M, Miller, KC, O'Connor, P, Hildebrandt, L, and Umberger, L. Sweat characteristics in individuals with varying susceptibilities of exercise-associated muscle cramps. J Strength Cond Res 36(5): 1171–1176, 2022—Many medical professionals believe dehydration and electrolyte losses cause exercise-associated muscle cramping (EAMC). Unlike prior field studies, we compared sweat characteristics in crampers and noncrampers but accounted for numerous factors that affect sweat characteristics including initial hydration status, diet and fluid intake, exercise conditions, and environmental conditions. Sixteen women and 14 men (mean ± SD; age = 21 ± 2 year, body mass = 69.1 ± 11.6 kg, height = 171.4 ± 9.9 cm) self-reported either no EAMC history (n = 8), low EAMC history (n = 10), or high EAMC history (n = 12). We measured V̇o
2max, and subjects recorded their diet. At least 3 days later, subjects ran at 70% of their V̇o
2max for 30 minutes in the heat (39.9 ± 0.6° C, 36 ± 2% relative humidity). Dorsal forearm sweat was collected and analyzed for sweat sodium concentration ([Na+]sw), sweat potassium concentration ([K+]sw), and sweat chloride concentration ([Cl−]sw). Sweat rate (SWR) was estimated from body mass and normalized using body surface area (BSA). Dietary fluid, Na+, and K+ ingestion was estimated from a 3-day diet log. We observed no differences for any variable among the original 3 groups (p = 0.05–p = 0.73). Thus, we combined the high and low cramp groups and reanalyzed the data against the noncramping group. Again, there were no differences for [Na+]sw (p = 0.68), [K+]sw (p = 0.86), [Cl−]sw, (p = 0.69), SWR/BSA (p = 0.11), dietary Na+ (p = 0.14), dietary K+ (p = 0.66), and fluid intake (p = 0.28). Fluid and electrolyte losses may play a more minor role in EAMC genesis than previously thought.
Acute Effects of Squats Using Elastic Bands on Postactivation Potentiation
Authors: Peng Hsien-Te , Zhan Dai-Wei , Song Chen-Yi , Chen Zong-Rong , Gu Chin-Yi , Wang I-Lin , Wang Li-I
Published: August 2020

Peng, H-T, Zhan, D-W, Song, C-Y, Chen, Z-R, Gu, C-Y, Wang, I-L, and Wang, L-I. Acute effects of squats using elastic bands on postactivation potentiation. J Strength Cond Res 35(12): 3334–3340, 2021—The study aimed to investigate the acute effects of squats using elastic bands at different resistance and recovery time points on postactivation potentiation (PAP). Fifteen male collegiate physical education students volunteered to participate in the study. Subjects were assigned to 6 experimental visits, which consisted of repeated factors that were 2 resistance squats (3 repetition maximum [RM] and 5RM) with elastic bands as intervention and 3 performance tests (countermovement jumps [CMJs], 20-m sprints, and change of direction [COD]). The performance test was measured before the resistance squat (pre-test) and at 15 seconds, 4 minutes, and 8 minutes after the resistance squat (post-tests) on each visit. An AMTI force plate and a set of Optojump sensors were used to obtain ground reaction force data during the CMJs and during the 20-m sprints and COD test, respectively. Repeated-measures two-way analyses of variance were performed for the resistance squats and recovery time points for each dependent variable. The 20-m sprint and COD test times at the 4-minute recovery time point after 3RM and 5RM resistance squatting were shorter than the pre-test values (p < 0.05). The rates of force development at the 4- and 8-minute recovery time points after 5RM resistance squatting were higher than the corresponding pre-test values (p < 0.05). All test performance variables significantly decreased at the 15-second recovery time point (p < 0.05). The use of elastic bands in 3RM and 5RM resistance squatting as a warm-up activity may positively affect PAP to improve sprinting, COD ability, and jump explosiveness at the 4-minute recovery time point.
Strength and Conditioning Coaches' Perceptions of Sport Psychology Strategies
Authors: Quartiroli Alessandro , Moore Erin Whitney Grandy , Zakrajsek Rebecca A.
Published: August 2020

Quartiroli, A, Moore, EWG, and Zakrajsek, RA. Strength and conditioning coaches' perceptions of sport psychology strategies. . J Strength Cond Res 36(5): 1327–1334, 2022—Strength and conditioning coaches (SCCs) hold a central role in the development of student-athletes. Although they certainly focus on student-athletes' physical skill development, SCCs are in an ideal position to integrate mental skills into their strength and conditioning sessions. For example, sport psychology (SP) strategies can be used within strength and conditioning sessions to assist in athlete exercise execution by regulating arousal, improving concentration, confidence, as well as improve self-correction through self-talk and imagery. The purpose of this study was to assess collegiate SCCs' use of SP skills/strategies. A total sample of 415 SCCs (19.7% return rate) across the United States participated in an online survey. Although the majority of these coaches reported having less than moderate training in SP (59.9%), they also reported a moderate to high use of certain SP strategies (e.g., goal setting, self-talk). Strength and conditioning coaches' familiarity with, knowledge of, and confidence to use the SP strategies were found to be predictors of SCCs' frequency of SP strategy use. This study aimed to provide an initial exploration of SCCs' understanding and use of specific SP strategies, which was influenced by the SCCs' perceived level of preparation to use these strategies. For SCCs to be able to purposefully and confidently incorporate SP strategies into training sessions, the current study suggests the need for specific training aimed to enhance the SCCs' knowledge of and confidence in using specific SP strategies.
Monitoring Heart Rate Variability and Perceived Well-Being in Brazilian Elite Beach Volleyball Players: A Single-Tournament Pilot Study
Authors: Nakamura Fábio Y. , Torres Vitor Bruno Cavalcanti , da Silva Leopoldo Sindice , Gantois Petrus , Andrade Ana Denise , Ribeiro André Luiz Berzoti , Brasileiro-Santos Maria do Socorro , Batista Gilmário Ricarte
Published: August 2020

Nakamura, FY, Torres, VBC, da Silva, LS, Gantois, P, Andrade, AD, Ribeiro, ALB, Brasileiro-Santos, MdS, and Batista, GR. Monitoring heart rate variability and perceived well-being in Brazilian elite beach volleyball players: A single-tournament pilot study. J Strength Cond Res 36(6): 1708–1714, 2022—The aim of this study was to monitor the changes in heart rate variability (HRV) and perceptual well-being status after a beach volleyball (BV) tournament day in high-level U17 and senior players. Seventeen BV players (U17 [15–16 years]: n = 08; and senior [19–41 years]: n = 09) competing at national and/or international BV level participated in this study. Resting HRV and perceptual well-being measures were recorded across 4 moments: night 1 (prematches night), morning 1 (prematches morning), night 2 (postmatches night), and morning 2 (postmatches morning). Session rating of perceived exertion was assessed 10 minutes after each match, and accumulated match loads were used for analysis. Senior players presented higher values of natural logarithm of square root of the mean squared differences of successive RR intervals (lnRMSSD) at the 4 observation moments than U17 players (p = 0.006). Within-subjects analysis showed a larger mean difference regarding both lnRMSSD and natural logarithm SD of normal R-R intervals (lnSDNN) between night 1 vs. night 2 in U17 players (effect size = 1.11 and, 0.96, respectively) compared with senior (effect size = 0.40 and 0.32, respectively). Accumulated match loads were negatively correlated with percentage change in lnRMSSD (r = −0.54; p = 0.037). U17 players showed higher well-being variation than senior (group × time; p = 0.02). In conclusion, the lnRMSSD index was able to discriminate the U17 and senior BV players, and maintaining high vagally related HRV indices is an important response to BV training and competition.
Long-Term Strength Adaptation: A 15-Year Analysis of Powerlifting Athletes
Authors: Latella Christopher , Teo Wei-Peng , Spathis Jemima , van den Hoek Daniel
Published: August 2020

Latella, C, Teo, W-P, Spathis, J, and van den Hoek, D. Long-term strength adaptation: A 15-year analysis of powerlifting athletes. J Strength Cond Res 34(9): 2412–2418, 2020—Strength is a fundamental component of athletic performance and development. This investigation examined the long-term strength development of powerlifting (PL) athletes. The rate of strength gain/day was assessed in 1897 PL athletes (F = 626, M = 1,271) over a 15-year period (2003–2018). Independent T-tests explored sex differences in baseline absolute (kg) and relative strength (kg·body mass−1 [bm]) recorded from the first competition, and strength gain/day (kg·d−1). Analyses based on initial strength quartiles were conducted using one-way analysis of variances with significance set at p < 0.05. Bivariate correlational analysis tested for relationships between strength gain/day and baseline strength, the number of competitions, and mean days between competitions. Males had greater absolute (M: 513.3 ± 99.8 kg, F: 289.4 ± 55.7 kg, p < 0.001) and relative (M: 5.89 ± 1.04 kg·bm−1, F: 4.27 ± 0.85 kg·bm−1, p < 0.001) strength at baseline. Overall, strength gain/day (F: 0.12 ± 0.69 kg·d−1, M: 0.15 ± 0.44 kg·d−1, p = 0.318) was similar between sexes. However, the strongest males showed a lower rate of strength improvement (0.102 kg·d−1) compared with least strong males (0.211 kg·d−1), p = 0.010. No differences were observed across quartiles for females. Correlational analyses revealed significant but weak negative relationships between strength gain/day and the mean days between competitions for females (r
2 = −0.120, p = 0.003) and males (r
2 = −0.190, p < 0.001). Similar relationships were observed for baseline strength (r
2 = −0.073, p = 0.009) and the number of competitions (r
2 = −0.111, p < 0.001) for males. The results suggest similar strength adaptation between sexes. The strongest males improve more slowly, possibly due to a ceiling effect. Collectively, the findings provide novel evidence of real-world long-term strength adaptations that may be particularly useful to understand athlete development, to aid periodized programming, and to benchmark strength over time.
Effect of Traditional, Cluster, and Rest Redistribution Set Configurations on Neuromuscular and Perceptual Responses During Strength-Oriented Resistance Training
Authors: Cuevas-Aburto Jesualdo , Jukic Ivan , Chirosa-Ríos Luis Javier , González-Hernández Jorge Miguel , Janicijevic Danica , Barboza-González Paola , Guede-Rojas Francisco , García-Ramos Amador
Published: August 2020

Cuevas-Aburto, J, Jukic, I, Chirosa-Ríos, LJ, González-Hernández, JM, Janicijevic, D, Barboza-González, P, Guede-Rojas, F, and García-Ramos, A. Effect of traditional, cluster, and rest redistribution set configurations on neuromuscular and perceptual responses during strength-oriented resistance training. J Strength Cond Res 36(6): 1490–1497, 2022—This study aimed to compare the acute effect of traditional (TR), cluster (CL), and rest redistribution (RR) set configurations on neuromuscular and perceptual measures of fatigue. Thirty-one resistance-trained men randomly performed a Control session and 3 experimental sessions consisting of the squat (SQ) and bench press (BP) exercises performed against the 10 repetition maximum load using TR (3 sets of 6 repetitions; 3 minutes of interset rest), CL (3 sets of 6 repetitions; 30 seconds of intraset rest every 2 repetitions; 3 minutes of interset rest), and RR (9 sets of 2 repetitions; 45 seconds of interset rest) set configurations. A significant effect of “set configuration” (p = 0.002) was observed for barbell velocity. The average velocity of the training session was lower for TR compared with CL (% difference = 5.09% in SQ and 5.68% in BP) and RR (% difference = 5.92% in SQ and 2.71% in BP). The 3 set configurations induced comparable decrements in countermovement jump height (% difference from −6.0% to −8.1%) and throwing velocity (% difference from −0.6% to −1.2%). Ratings of perceived exertion (RPE-10) values collected after the sets were higher for TR (SQ: 6.9 ± 0.7 a.u.; BP: 6.8 ± 0.8 a.u.) compared with CL (SQ: 6.2 ± 0.8 a.u.; BP: 6.4 ± 0.7 a.u.) and RR (SQ: 6.2 ± 0.8 a.u.; BP: 6.6 ± 0.9 a.u.), while the session RPE did not differ between the set configurations (p = 0.595). CL and RR set configurations allow for higher velocities and lower RPE values during resistance training sessions not performed to failure in comparison with a TR set configuration.
Effects of Multi-ingredient Preworkout Supplements on Physical Performance, Cognitive Performance, Mood State, and Hormone Concentrations in Recreationally Active Men and Women
Authors: Beckner Meaghan E. , Pihoker Alexis A. , Darnell Matthew E. , Beals Kim , Lovalekar Mita , Proessl Felix , Flanagan Shawn D. , Arciero Paul J. , Nindl Bradley C. , Martin Brian J.
Published: August 2020

Beckner, ME, Pihoker, AA, Darnell, ME, Beals, K, Lovalekar, M, Proessl, F, Flanagan, SD, Arciero, PJ, Nindl, BC, and Martin, BJ. Effects of multi-ingredient preworkout supplements on physical performance, cognitive performance, mood state, and hormone concentrations in recreationally active men and women. J Strength Cond Res 36(9): 2493–2501, 2022—Performance enhancement supplement research has primarily focused on the effectiveness of individual ingredients, rather than the combination. This study investigated the acute effects of 2 multi-ingredient preworkout supplements (MIPS), with beta-alanine and caffeine (BAC) and without (NBAC), compared with placebo (PLA) on anaerobic performance, endurance capacity, mood state, cognitive function, vascular function, and anabolic hormones. Thirty exercise-trained individuals (24.4 ± 4.9 years, 15 men and 15 women) completed a fatiguing exercise protocol on 3 separate occasions, 30 minutes after ingestion of BAC, NBAC, or PLA. Outcomes were analyzed using one-way or two-way repeated-measures analysis of variance, as appropriate (alpha = 0.05). Anaerobic power was greater when supplementing with NBAC (10.7 ± 1.2 W·kg−1) and BAC (10.8 ± 1.4 W·kg−1) compared with PLA (10.4 ± 1.2 W·kg−1) (p = 0.014 and p = 0.022, respectively). BAC improved V̇o
2peak time to exhaustion (p = 0.006), accompanied by an increase in blood lactate accumulation (p < 0.001), compared with PLA. Both NBAC and BAC demonstrated improved brachial artery diameter after workout (p = 0.041 and p = 0.005, respectively), but PLA did not. L-arginine concentrations increased from baseline to postsupplement consumption of BAC (p = 0.017). Reaction time significantly decreased after exercise for all supplements. There was no effect of supplement on mood states. Exercise-trained individuals looking to achieve modest improvements in power and endurance may benefit from consuming MIPS before exercise.
Assisted Jumping in Healthy Older Adults: Optimizing High-Velocity Training Prescription
Authors: Tufano James J. , Vetrovsky Tomas , Stastny Petr , Steffl Michal , Malecek Jan , Omcirk Dan
Published: August 2020

Tufano, JJ, Vetrovsky, T, Stastny, P, Steffl, M, Malecek, J, and Omcirk, D. Assisted jumping in healthy older adults: optimizing high-velocity training prescription. J Strength Cond Res 36(6): 1518–1523, 2022—Because older adults benefit from power training, training strategies for athletes such as supramaximal velocity–assisted jumping could also be useful for older adults. However, optimizing-assisted exercise prescription in older adults remains uninvestigated. Therefore, the purpose of this study was to determine the effects of different bodyweight (BW) assistance levels on jumping force and velocity in healthy older adults. Twenty-three healthy older adults (67.6 ± 7.6 years, 167.0 ± 8.8 cm, 72.7 ± 14.3 kg, and 27.1 ± 6.9% body fat) performed 5 individual countermovement jumps at BW, 90, 80, 70, and 60% of BW. Jumps were performed on a force plate, which provided peak take-off force (TOF), flight time, and peak impact force. A linear position transducer measured peak concentric velocity (PV). The rating of perceived exertion (RPE) was also assessed after each condition. Take-off force was greater during BW than all other conditions, 90 and 80% were greater than 70 and 60%, but there were no differences between 80 and 90% or between 70 and 60%. The FT progressively increased at all assistance levels, and PV was faster for all assistance levels than BW, with no differences between assistance levels. Impact force was greater during BW than 80, 70, and 60% and was greater during 90% than 60%. The RPE was less than BW during all assistance conditions but was the least during 70%. Implementing assisted jumping between 70 and 80% of BW in older adults likely provides the ideal combination of force, velocity, and RPE.
The Relationship Between the National Football League Scouting Combine and Game Performance Over a 5-Year Period
Authors: Cook Jordan , Ryan Greg A. , Snarr Ronald L. , Rossi Stephen
Published: August 2020

Cook, J, Ryan, GA, Snarr, RL, and Rossi, S. The relationship between the National Football League scouting Combine and game performance over a 5-year period. J Strength Cond Res 34(8): 2492–2499, 2020—There has been doubt on the ability of the National Football League (NFL) Scouting Combine to predict successful future game performance. This study analyzed data from athletes who participated in the Combine between 2013 and 2017 (n = 1,537) and their subsequent year's performance in the NFL. Data from 6 athletic measures were normalized for each athlete when compared with all other athletes (avgCZ) and athletes of the same position (avgPZ). Correlational analysis was used to ascertain whether the physical performance tests were associated with subsequent year's game performance (avgS). A multiple linear regression was performed to examine whether individual event Combine performance could predict the subsequent year's avgS in the NFL. Of the 35 correlations found when examining relationships, only 2 correlations were found to be moderately strong, avgCZ—avgS2 (r = 0.320), avgPZ—avgS2 (r = 0.332), whereas most were found to be weak (r < 0.3). Furthermore, data analysis suggests that Combine measures can only explain approximately 2.6% of the variance in avgS 1 year after the Combine when using 3 (vertical jump, bench press, and PRO) performance tests as predictors. The primary results of this study suggest that the NFL Combine lacks predictive ability when examining first year game performance. Furthermore, it also lacks correlational strength when examining relationships between performance and subsequent 5-year performance in the NFL. Caution should be used if coaches, general managers, and other front office staff are considering the use of Combine data as a possible selection for the upcoming NFL Draft.
Relative Age Effect in Russian Elite Hockey
Authors: Bezuglov Eduard , Shvets Evgeny , Lyubushkina Anastasiya , Lazarev Artemii , Valova Yulia , Zholinsky Andrey , Waśkiewicz Zbigniew
Published: August 2020

Bezuglov, E, Shvets, E, Lyubushkina, A, Lazarev, A, Valova, Y, Zholinsky, A, and Waśkiewicz, Z. Relative age effect in Russian elite hockey. J Strength Cond Res 34(9): 2522–2527, 2020—A considerable amount of literature has been published on relative age effect (RAE) in many sports; however, only a few studies have investigated this phenomenon in European elite ice hockey. The objective of this research was to study RAE prevalence in Russian elite ice hockey, which for years has been holding leading positions in global ice hockey. To estimate RAE prevalence, birthdates of recruits of leading ice hockey academies, players of the leading junior and adult teams, and most successful Russian-born National Hockey League (worlds' strongest ice hockey league) players were identified (n = 2,285). A high prevalence of RAE was identified. The number of players born in the first half of the year was higher than those born later in the year—65.5 and 34.5%, respectively. The RAE prevalence was high among all age groups of recruits of the leading Russian hockey academies and junior teams. In contrast to junior hockey, more players born in the fourth quarter of the year were identified in elite adult teams. The high prevalence of RAE in Russian hockey might be explained by the fact of a high level of competition among young players during recruitment to hockey academies. Moreover, the coaches aim to achieve immediate progress, thus selecting more mature players who are better physically developed. However, “later-born” are widely present in elite adult ice hockey leagues.
Muscle Forces During the Squat, Split Squat, and Step-Up Across a Range of External Loads in College-Aged Men
Authors: Kipp Kristof , Kim Hoon , Wolf William I.
Published: August 2020

Kipp, K, Kim, H, and Wolf, WI. Muscle forces during the squat, split squat, and step-up across a range of external loads in college-aged men. J Strength Cond Res 36(2): 314–323, 2022—Knowledge about the load-dependent demand placed on muscles during resistance training exercises is important for injury prevention and sports performance training programs. The purpose of this study was to investigate the effect of external load on lower extremity muscle forces during 3 common resistance training exercises. Nine healthy subjects performed 4 sets of the squat (SQ), split squat (SS), and step-up (SU) exercises each with 0, 25, 50, and 75% of body mass as additional load. Motion capture and force plate data were used to estimate individual muscle forces of 11 lower extremity muscles through static optimization. The results suggest load-dependent increases in muscle forces for the m. gluteus maximus, m. gluteus medius, vastus lateralis, m. vastus medius, m. vastus intermedius, m. semitendinosus, m. semimembranosus, m. biceps femoris long head, m. soleus, m. gastrocnemius lateralis, and m. gastrocnemius medialis during the execution of all 3 exercises. In addition, load-dependent increases in m. gluteus maximus, vastus lateralis, m. vastus medius, m. vastus intermedius, and m. biceps femoris long head forces were often more pronounced during the SS and SU than the SQ across the range of loads used in this study. These results suggest that the mechanical demands imposed by resistance training exercises scale with external load and that the extent of that scaling depends on the specific exercise.
The Effect of Blood Flow Restriction Therapy on Recovery After Experimentally Induced Muscle Weakness and Pain
Authors: Wong Vickie , Dankel Scott J. , Spitz Robert W. , Bell Zachary W. , Viana Ricardo B. , Chatakondi Raksha N. , Abe Takashi , Loenneke Jeremy P.
Published: August 2020

Wong, V, Dankel, SJ, Spitz, RW, Bell, ZW, Viana, RB, Chatakondi, RN, Abe, T, and Loenneke, JP. The effect of blood flow restriction therapy on recovery after experimentally induced muscle weakness and pain. J Strength Cond Res 36(4): 1147–1152, 2022—The purpose was to determine if blood flow restriction with no external load could be used as a means of active therapy after experimentally induced fatigue and soreness. Twelve women and 7 men (aged 18–35 years) participated in a randomized controlled trial using a within-subject design. The study intervention was 3 consecutive visits. Visit 1 included the fatiguing/soreness-inducing protocol for the elbow flexors, which was performed only once during the study. Torque was measured before/after to confirm individuals began in a weakened state. Subjects then completed blood flow restriction therapy on one arm and the sham therapy on the other. Subjects performed elbow flexion/contraction with no external load on both arms. Torque was measured once more 10 minutes after the fatiguing/soreness-inducing protocol. Twenty-four hours later, soreness and torque were assessed in each arm, followed by another bout of therapy. Forty-eight hours after the initial visit, soreness and torque were measured again. There were no differences (median difference [95% credible interval]) in the recovery of torque between the blood flow restriction and sham therapy conditions at 10 minutes (0.5 [−2.7, 3.8] N·m), 24 hours (−2.34 [−6, 1.14] N·m), or 48 hours (−1.94 [−5.45, 1.33] N·m). There were also no differences in ratings of soreness at 24 hours (−2.48 [−10.05, 5.05]) or 48 hours (2.58 [−4.96, 10.09]). Our results indicate that this specific model of blood flow restriction therapy did not enhance the recovery of the muscle compared with a sham condition without the application of pressure.
Validity, Reliability, and Sensitivity to Exercise-Induced Fatigue of a Customer-Friendly Device for the Measurement of the Brain's Direct Current Potential
Authors: Valenzuela Pedro L. , Sánchez-Martínez Guillermo , Torrontegi Elaia , Vázquez-Carrión Javier , Montalvo Zigor , Kara Olga
Published: August 2020

Valenzuela, PL, Sánchez-Martínez, G, Torrontegi, E, Vázquez-Carrión, J, Montalvo, Z, and Kara, O. Validity, reliability, and sensitivity to exercise-induced fatigue of a customer-friendly device for the measurement of the brain's direct current potential. J Strength Cond Res 36(6): 1605–1609, 2022—This study aimed to determine the validity, reliability, and sensitivity to exercise-induced fatigue of the brain's direct current (DC) potential measured with a commercially available and customer-friendly electroencephalography (EEG) device and Omegawave (OW). The study was composed of 3 different experiments as follows: (a) we compared the DC potential values obtained simultaneously in 31 subjects with both OW and a research-quality EEG system; (b) 3 consecutive DC potential measurements with OW were taken at rest on the same day in 25 subjects for reliability analyses; and (c) sensitivity to fatigue was assessed in 9 elite badminton players through the measurement of the DC potential with OW—as well as other fatigue-related measures (e.g., Hooper's index, heart rate variability, jump ability, and simple and complex reaction times)—24 hours after both a day of rest and of strenuous exercise, which were performed in a crossover and randomized design. The DC potential measured with OW was reliable (intraclass correlation coefficient = 0.97) and significantly correlated to that of EEG (r = 0.55, p = 0.001), although significant differences were observed between systems (p < 0.001). Compared with the rest day, strenuous exercise resulted in an impaired Hooper's index (p = 0.010) and jump ability (p = 0.008), longer simple (p = 0.038) and complex reaction times (p = 0.011), and a trend toward sympathetic dominance (standard deviation of normal to normal R-R intervals, p = 0.042; root mean square of differences between consecutive R-R intervals, p = 0.068). In turn, no significant differences were found between sessions for the DC potential (p = 0.173). In summary, the DC potential measured with OW was reliable and modestly correlated to that measured with EEG, but no differences were observed in response to the delayed fatigue (after 24 hours) elicited by strenuous exercise in elite athletes.
Relationship Between Strength and Conditioning Assessments and Rowing Performance in Female Collegiate Athletes
Authors: Folk Amanda L. , Garcia Christina A. , Whitney Samuel H. , Kovacs Sara J.
Published: August 2020

Folk, AL, Garcia, CA, Whitney, SH, and Kovacs, SJ. Relationship between strength and conditioning assessments and rowing performance in female collegiate athletes. J Strength Cond Res 36(6): 1618–1621, 2022—The purpose of this study was to examine the relationship between strength and conditioning variables and rowing performance, as measured by a 2000 m ergometer time, in female collegiate rowers. Twenty-four female collegiate rowers qualified for this study by completing both types of assessments and a demographic questionnaire. Pearson correlation coefficients (r) were used to determine the association between the total 2000 m ergometer time and each strength and conditioning assessment. The assessments included a 1 repetition maximum (1RM) squat and a 1RM hang clean. After this, all significant correlations were placed in a stepwise linear regression analysis to predict the total 2000 m ergometer time. The 1RM squat and 1RM hang clean correlated with 2000 m ergometer performance (p = 0.034 and p = 0.002, respectively). Only the 1RM squat emerged as a predictor of 2000 m ergometer performance. This study highlights that the 1RM squat may be a way to predict rowing performance and build successful female collegiate rowing teams.
A Congested Match Schedule Alters Internal Match Load and Affects Salivary Immunoglobulin A Concentration in Youth Soccer Players
Authors: Mortatti Arnaldo Luis , Oliveira Romerito Sóstenes Canuto de , Pinto Júlio Cesar Barbosa de Lima , Galvão-Coelho Nicole Leite , de Almeida Raíssa Nóbrega , Aoki Marcelo S. , Moreira Alexandre
Published: August 2020

Mortatti, AL, Oliveira, RSCd, Pinto, JCBdL, Galvão-Coelho, NL, Almeida, RN, Aoki, MS, and Moreira, A. A congested match schedule alters internal match load and affects salivary immunoglobulin A concentration in youth soccer players. J Strength Cond Res 36(6): 1655–1659, 2022—The aim of this study was to analyze the effects of a congested match schedule (CMS) undertaken after a tapering week, on internal match load (IML) and salivary immunoglobulin A (SIgA) concentration in 12 youth soccer players (16.6 ± 0.5 years; 175 ± 8 cm; 65 ± 8 kg) who performed 4 official matches within a 4-day period. Internal match load was determined using the session-rating of perceived exertion method and the competitive strain (CS) and monotony index (MI) were also determined. Saliva sampling was conducted, before the last training day of a tapering week (training) preceding the CMS, 60 minutes before the first match (match-1), and 22 hours after match 4 (postmatch 4). Salivary immunoglobulin A was analyzed by ELISA. The results of the analysis of variance with repeated measures showed a significant difference for IML across the matches (p < 0.001). A significant reduction in SIgA was observed from prematch 1 to postmatch 4 (p = 0.019). Regarding the change in SIgA (ΔSIgA), 58.3% of the players presented values equal/higher than the minimal detectable change. A large within-individual correlation was observed between ΔSIgA and MI and CS (r = 0.71 and r = 0.72: p < 0.01, respectively). The current findings suggest that youth players participating in a CMS may present a decrease in mucosal immunity function. In addition, data suggest that the MI and CS may be used as valuable markers for monitoring competition load during CMS in youth soccer players.
Psychophysiological Stress Markers During Preseason Among Elite Female Soccer Players
Authors: Botelho Renata , Abad Cesar C.C. , Spadari Regina C. , Winckler Ciro , Garcia Márcia C. , Guerra Ricardo L.F.
Published: August 2020

Botelho, R, Abad, CCC, Spadari, RC, Winckler, C, Garcia, MC, and Guerra, RLF. Psychophysiological stress markers during preseason among elite female soccer players. J Strength Cond Res 36(6): 1648–1654, 2022—This study aimed to investigate changes and correlations between mood states and various physiological stress markers after a 7-week preseason period among elite female soccer players. Twenty-four elite female soccer players participated in this study (26.4 ± 3.7 years). Their internal training load, mood states, day and evening salivary testosterone and cortisol concentrations, blood creatine kinase concentration (CK), and heart rate variability (HRV) were assessed during the first week of preseason (PRE), and again 7 weeks after a systematic training period (END). After the preseason, there were significant increases in subject negative mood scales (p ≤ 0.03; Effect Size [ES] > 0.60), total mood scores (p = 0.01; QI = 100/0/0; ES = 1.32), day and evening testosterone and cortisol concentrations (p ≤ 0.03; ES > 0.54), and CK concentrations (p = 0.01; QI = 100/0/0; ES = 1.54). Correlations were found between cortisol and tension (r = 0.53 and 0.60; p ≤ 0.02), cortisol and confusion (r = 0.75; p = 0.01), and cortisol and the LF/HF index of HRV (r = −0.52; p = 0.04). Mood states (except vigor), salivary testosterone, and cortisol concentrations, as well as CK, showed significant changes after a 7-week systematic training system. The cortisol was the factor most highly related to various mood states (including tension and confusion), and with the HRV indices. Coaches and researchers can use these data to design, monitor, and control soccer training programs, in particular throughout the preseason period.
Greater Fitness Is Associated With Improved Functional Movement Characteristics in Explosive Ordnance Disposal Technicians
Authors: Hernández Lisa M. , Coffin Stephanie D. , Taylor Marcus K.
Published: August 2020

Hernández, LM, Coffin, SD, and Taylor, MK. Greater fitness is associated with improved functional movement characteristics in explosive ordnance disposal technicians. J Strength Cond Res 36(6): 1731–1737, 2022—Low fitness and poor functional movement (FM) have been linked to higher musculoskeletal injury risk. The FM Screen (FMS) and Y-Balance Test (YBT) are useful indicators of potential injury risk in military personnel. U.S. Navy Explosive Ordnance Disposal (EOD) technicians are the premier combat force for countering explosive hazards and must operate in austere environments. To safeguard health and mission success, it is critical to assess factors related to injury risk in this specialized military population. This study evaluated the relationship between fitness and FM characteristics in 64 male EOD technicians (mean age ± SD = 34.2 ± 7.0 years). Body fat percentage (BF%), maximum volume of oxygen uptake (V̇o
2max), muscular strength, and FM (i.e., FMS, YBT) were assessed. Body fat percentage and V̇o
2max were associated with FMS and YBT scores (all p < 0.05). A nonlinear model further revealed that the group with the lowest V̇o
2max values had the bottommost FMS and YBT scores (all p < 0.01), but FM scores did not differ among those with a higher V̇o
2max, implying a “threshold” effect. No correlations were observed with muscular strength. By characterizing the unique and shared contributions of BF% and V̇o
2max, and exploring the nonlinear relationship between V̇o
2max and FM, this study expands on accruing data that indicate individuals who are more physically fit have better FM and lower injury risk. Although muscular strength is a critical element of overall fitness, body composition and cardiorespiratory fitness may more strongly influence FM and injury risk.
The Effects of Physical Fitness on Postactivation Potentiation in Professional Soccer Athletes
Authors: Guerra Mauro A. , Caldas Leonardo C. , Souza Helder L. , Tallis Jason , Duncan Michael J. , Guimarães-Ferreira Lucas
Published: August 2020

Guerra, MA Jr, Caldas, LA, Souza, HL, Tallis, J, Duncan, MJ, and Guimarães-Ferreira, L. The effects of physical fitness on postactivation potentiation in professional soccer athletes. J Strength Cond Res 36(6): 1643–1647, 2022—To investigate the relationship of the response to postactivation potentiation (PAP) with scores of physical fitness. Twenty-four professional male soccer players undertook tests of agility, muscular power, aerobic capacity, and body composition. Conditioning activities (CAs) were performed consisting of plyometrics exercises and sprints with sled towing. In the first and second sessions, body composition, agility, power, and aerobic capacity were assessed. At the third session, countermovement jumps (CMJ) were performed with 1, 3, and 5 minutes after the execution of the CA. Significant differences were found for CMJ height 1, 3, and 5 minutes after the CA compared with baseline values (3.58, 5.10, 5.48%, respectively). There was a significant positive correlation between the level of general physical fitness and PAP (CMJ height increase) 5 minutes after (r = 0.73). When the athletes were divided into groups with higher and lower physical fitness, the CA caused a significant increase in CMJ height in both groups, but a significant difference (p < 0.05) was observed at all times after PAP induction, with better performance in higher versus lower fitness level. The results suggest that plyometrics exercises associated with sled towing sprints as a CA result in an increase in CMJ performance in athletes and that physical fitness directly influences the PAP occurrence, with higher fit players demonstrating an enhanced PAP response.