bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidencias de validez factorial de la Escala de desesperanza de Beck en español con muestras clínicas y no clínicas
Authors: Hermosillo-de la Torre Alicia Edith , Méndez-Sánchez Cecilia , Gonzalez-Betanzos Fabiola
Published: August 2020

El propósito del presente estudio fue evaluar la estructura interna de la adaptación al español de Escala de Desesperanza de Beck et al. (1974), dada su utilidad y relevancia en la predicción de conductas suicidas. Para esto, se analizaron las respuestas a la escala de 1260 estudiantes universitarios (M = 4.79; DT = 4.29) y de una muestra clínica en la que participaron 150 jóvenes con intento de suicidio de alta letalidad (M = 8.51; DT = 2.38). Se examinó la estructura interna por medio del Análisis factorial confirmatorio (AFC) en tres fases: en la primera, se comparó el modelo original con cuatro modelos encontrados en las diferentes adaptaciones al español; en la segunda, se tomaron en cuenta modelos que analizan la aquiescencia; y en la tercera, se hizo una validación cruzada de esos modelos con población clínica. Los resultados señalan que la escala es unidimensional tanto en el caso de las muestras clínicas (χ2 = 154.84, gl = 135, p < 0.001, CFI = 0.99, TLI = 0.99,RMSEA = 0.03) como en la población universitaria; sin embargo, a esta última se le añadió un factor de método para el tratamiento de la aquiescencia (χ2 = 252.14, gl = 134, p < 0.001, CFI = 0.95, TLI = 0.94, RMSEA = 0.03). Los resultados muestran la importancia de utilizar análisis y modelos que consideren la naturaleza de los datos y las características de la muestra para aportar evidencias más sólidas para la validez de constructo.
Vítimas de bullying, sintomas depressivos, ansiedade, estresse e ideação suicida em adolescentes
Authors: Pimentel Fernanda de Oliveira , Cristina Cristina Pilla Della Méa , Dapieve Patias Naiana
Published: August 2020

Objetivou-se verificar a correlação entre ser vítima de bullying, ter sintomas depressivos, de ansiedade, de estresse e ideação suicida em adolescentes. Além disso, foi identificado se havia diferença nos construtos investigados, por gênero e idade. Estudo quantitativo transversal, do qual participaram 117 adolescentes. Utilizaram-se os instrumentos: questionário sociodemográfico, Escala Califórnia de Vitimização do Bullying, Escala de Depressão, Ansiedade e Estresse, e Escala Beck de Suicídio. As análises foram realizadas por meio de estatística descritiva, correlação de Spearman e teste U de MannWhitney. Os resultados indicam que 48,71 % da amostra apresenta ideação suicida. Houve correlação positiva entre ser vítima de bullying e ter sintomas depressivos, ansiedade e estresse, e ser vítima e ter ideação suicida. As meninas apresentam mais sintomas de estresse do que os meninos, e adolescentes mais novos são mais vítimas de bullying do que os mais velhos. Destaca-se, assim, a relevância da discussão desse tema, tanto nas escolas quanto nas famílias, a fim de diminuir o sofrimento psíquico das vítimas.
Variáveis pessoais e contextuais preditoras de perpetração de violência no namoro na adolescência
Authors: Lessinger Borges Jeane , Assumpção Heine Julia , Dell'Aglio Débora D.
Published: August 2020

Estudos prévios indicam que ser vítima de maus-tratos na infância e testemunhar a violência conjugal dos pais são preditores da violência no namoro na adolescência. A influência do grupo de pares, o uso de álcool e ser do sexo feminino igualmente aumentam o risco para a violência no namoro, embora ainda sejam variáveis pouco investigadas. Dessa forma, este estudo transversal descritivo investigou variáveis pessoais e contextuais associadas à perpetração de violência no namoro em 403 adolescentes, de 14 a 19 anos, de escolas públicas e privadas da Região Metropolitana de Porto Alegre, Brasil. Uma análise de regressão logística multivariada indicou que ter sofrido maus-tratos psicológicos na infância aumenta em 5,37 (IC 95 % = 2,30-12,57) a probabilidade de um adolescente ser perpetrador de violência verbal ou emocional no namoro. Demais variáveis preditoras (testemunhar violência parental, influência do grupo de pares, uso de álcool e ser do sexo feminino) não se mostraram significativas. Este estudo reúne evidências de aspectos intergeracionais da violência no namoro e indica a necessidade de programas de prevenção com adolescentes.
Egalitarian men: stereotypes and discrimination in the labor market
Authors: Viana Hyalle Abreu , Torres Ana Raquel Rosas , Álvaro Estriamana José Luis
Published: August 2020

This article aimed to analyze the stereotypes attributed to "egalitarian men", understood here as men who support gender equality in relation to domestic and family responsibilities as well as inclusion in the workforce. To do so, two studies were carried out. The first study investigated the attribution of stereotypes to egalitarian men through a single open question. A total of 250 university students participated in this study, of which 51.1% were male, and their average age was 21.5 years (SD = 4.39). The second study analyzed the attribution of stereotypes to egalitarian or traditional men and women in a work context considered masculine. Participants included 221 university students with a mean age of 21.9 years (SD = 4.19), the majority (54.3%) being male. Taken together, the results of the two studies indicate that the egalitarian man is perceived as fragile and possibly homosexual. On the other hand, he is also seen as being more competent than traditional men.
The hemostatic activity of Manilkara zapota (L.) P. Royen latex associated with fibrinogenolytic activity
Authors: Kusuma C G , Gubbiveeranna Vinod , Sumachirayu C K , Bhavana S , Ravikumar H , Nagaraju S
Published: August 2020

Manilkara zapota (L.) P. Royen (Sapotaceae), is widely used in traditional medicine for various ailments like, diarrhea, pulmonary diseases, piles, ulcers and to treat wounds. The present study evaluates the role of M. zapota latex in hemostasis. The processed latex named as M. zapota natant latex (MzNL), has proteins at the concentration of 8 mg/ml and showed protein bands in Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The proteolytic activity of MzNL was evaluated using casein in comparison with trypsin. The phenylmethylsulfonyl fluoride (PMSF) inhibited the protease activity indicating the possible presence of serine protease. The effect of temperature, pH and metal ions on proteolytic activity was evaluated. MzNL exhibited fibrinogenolytic activity by hydrolysing A? and B? subunits of fibrinogen. However, ? subunit remained resistant for hydrolysis. MzNL hydrolyzed all the subunits of collagen type I and IV at the concentration of 8 µg and 25 µg in 20 µl each respectively. MzNL showed procoagulant activity and is devoid of hemolytic activity. Fibrinogenolytic activity and procoagulant nature of MzNL suggests its possible role in blood coagulation that in turn restores hemostasis.
Antibacterial activities of ethanolic extract of four species of Rutaceae family
Authors: Van Hong Thien , Nguyen Dang Gia Man , Quynh Nguyen Tuong An , Le Van Son
Published: August 2020

In this study, the antibacterial activity of ethanolic extract from the leaves of four Rutaceae species, including Acronychia pedunculata, Clausena excavata, Glycosmis pentaphylla and Luvunga scandens, were performed using the agar disk diffusion method for the first time. The ethanolic extracts from the leaves of A. pedunculata and G. pentaphylla were able to resist against all six bacterial strains with zones of inhibition for Bacillus cereus (17.3±2.1 mm, 20.8±1.0 mm) Staphylococcus aureus (8.5±0.5 mm, 17.6±0.3 mm) Escherichia coli (16.7±2.1 mm, 15.3±1.2 mm), Pseudomonas aeruginosa (11.7±0.6 mm, 14.0±1.7 mm), Salmonella enteritidis (22.3±0.6 mm, 24.6±0.5 mm) and Salmonella typhimurium (9.5±0.9 mm, 8.3±0.6 mm). On the other hand, the ethanolic extract of C. excavata leaf was resistant to B. cereus (12.3±0.6 mm), S. aureus (11.6±0.5 mm), E. coli (11.5±2.1 mm), P. aeruginosa (10.6±0.3 mm) while B. cereus (8.2±0.3 mm), S. aureus (9.3±0.6 mm), E. coli (8.5±0.5 mm) and S. typhimurium (8.3±0.6 mm) were inhibited by the ethanolic extract of L. scandens leaf. This study could provide necessary information for further application of these species in medicine.
Agreement Between the Iron Path App and a Linear Position Transducer for Measuring Average Concentric Velocity and Range of Motion of Barbell Exercises
Authors: Kasovic Jovana , Martin Benjamin , Carzoli Joseph P. , Zourdos Michael C. , Fahs Christopher A.
Published: August 2020

Kasovic, J, Martin, B, Carzoli, JP, Zourdos, MC, and Fahs, CA. Agreement between the Iron Path app and a linear position transducer for measuring average concentric velocity and range of motion of barbell exercises. J Strength Cond Res 35(2S): S95–S101, 2021—The purpose of this study was to compare average concentric velocity (ACV) and range of motion (ROM) values measured by the Iron Path (IP) app to the previously validated Open Barbell System (OBS) linear position transducer during the front and back squat and conventional and sumo deadlift. Twenty-seven men and women (21 ± 3 years old; 76.7 ± 14.5 kg; 1.72 ± 0.09 m) with squat and deadlift training experience completed a modified one repetition maximum protocol on 4 separate occasions in a randomized order. The IP app and OBS device recorded ACV and ROM during each protocol. The level of statistical significant was set at p ≤ 0.05. Bland–Altman plots showed fairly large limits of agreement for both ACV and ROM. Furthermore, 95% confidence intervals for the intraclass correlation coefficients indicated the agreement in ACV between the devices for each of the 4 lifts to range from 0.648–0.876 to 0.849–0.930 and for agreement in ROM between devices to range from −0.053–0.480 to 0.545–0.770. Compared with the OBS, the IP app recorded significantly (p < 0.05) lower ACV values for the front squat and back squat and greater ROM values for the sumo deadlift. We suggest the IP app should not be used in place of a validated linear position transducer for measuring ACV or ROM for barbell lifts.
Senior and Junior Rugby League Players Improve Lower-Body Strength and Power Differently During a Rugby League Season
Authors: Wade Jarrod A. , Fuller Joel T. , Devlin Paul J. , Doyle Tim L.A.
Published: August 2020

Wade, JA, Fuller, JT, Devlin, PJ, and Doyle, TLA. Senior and junior rugby league players improve lower-body strength and power differently during a rugby league season. J Strength Cond Res 36(5): 1367–1372, 2022—This investigation evaluated lower-body strength and power changes across a rugby league season in elite junior and senior athletes. Twenty-five senior and 20 junior rugby league players performed an isometric midthigh pull and countermovement jump at 3 time points in a National Rugby League training season (mid-preseason, end-preseason, and in-season). Linear fixed-effects models were used to compare isometric midthigh pull force and countermovement jump power between player experience groups (senior vs. junior) across the season phases (mid-preseason vs. end-preseason vs. and in-season). Cohen's effect sizes (ES) with 95% confidence intervals were calculated for pairwise comparisons. For senior players, absolute and relative strength (ES = 0.38, p < 0.007) and power (ES = 0.64, p < 0.008) increases were observed at end-preseason compared with mid-preseason, but there were no changes in-season (ES = 0.02, p > 0.571). For junior players, strength did not change (ES < 0.01, p > 0.738) and absolute power decreased (ES = 0.29, p < 0.014) at end-preseason compared with mid-preseason; large increases were evident for absolute and relative strength (ES = 1.43, p < 0.001) and power (ES = 0.62, p < 0.001) in-season. This research demonstrates senior and junior rugby league players exhibit unique patterns of improvements in lower-body strength and power across different phases of the season. This highlights the importance for training programs to differ between junior and senior athletes and target different physical qualities for both groups at different times of the season, thus providing guidance for strength and conditioning coaches.
Acute Effects of Progressive Sled Loading on Resisted Sprint Performance and Kinematics
Authors: Pareja-Blanco Fernando , Pereira Lucas A. , Freitas Tomás T. , Alcaraz Pedro E. , Reis Valter P. , Guerriero Aristide , Arruda Ademir F.S. , Zabaloy Santiago , Sáez De Villarreal Eduardo , Loturco Irineu
Published: August 2020

Pareja-Blanco, F, Pereira, LA, Freitas, TT, Alcaraz, PE, Reis, VP, Guerriero, A, Arruda, AFS, Zabaloy, S, De Villarreal, ES, and Loturco, I. Acute effects of progressive sled loading on resisted sprint performance and kinematics. J Strength Cond Res 36(6): 1524–1531, 2022—We examined the effects of 5 loading conditions (0, 20, 40, 60, and 80% of body-mass [BM]) on resisted sprint performance and kinematics in male rugby players over different distances. Ten players from the Brazilian National Team (20.1 ± 3.3 years; 88.7 ± 18.8 kg; 178.3 ± 6.2 cm) performed 20-m sprints under the 5 loading conditions. Sprint times in 5, 10, and 20 m were recorded. Stride length (SL), and hip, knee, and ankle angles were measured using an eight-sensor motion analysis system. The kinematic parameters were calculated over the different distances. Heavier loads led to significantly greater velocity loss (p < 0.001–0.05). Significant reductions in SL were also observed when comparing 0% BM and all resisted sprints in all assessed distances (p < 0.001–0.05, effect size [ES]: 1.35–4.99). Very heavy (80% BM) sled load provoked significantly greater decreases in SL than the rest of loading conditions (p < 0.01–0.05). Important kinematic alterations were observed for all loading conditions and sprint distances when compared with 0% BM (ES: 0.76–1.79, for hip-angle; 0.20–1.40, for knee-angle; and 0.73–1.88, for ankle-angle). Moreover, 80% BM induced significantly higher hip flexion, lower knee flexion, and higher ankle dorsiflexion than 20% BM condition at 5–10 and 10–20 m distances (p < 0.05). Lighter sled loads (<40% BM) seem to be more adequate to improve speed ability without provoking drastic changes in the unloaded sprinting technique, whereas heavier loads may be more suitable for optimizing horizontal force production and thus, acceleration performance.
Mechanical and Contractile Properties of Knee Joint Muscles Measured by the Method of Tensiomyography in Differently Trained Men and Women
Authors: Toskić Lazar D. , Dopsaj Milivoj J. , Marković Milan R. , Toskić Dragan R. , Ignjatović Aleksandar M.
Published: August 2020

Toskić, LD, Dopsaj, MJ, Marković, MR, Toskić, DR, Ignjatović, AM. Mechanical and contractile properties of knee joint muscles measured by the method of tensiomyography in differently trained men and women. J Strength Cond Res 36(6): 1532–1539, 2022—The aim of this study was to investigate the differences in mechanical and contractile properties of knee joint flexor and extensor muscles between differently trained men and women, using tensiomyography (TMG). The sample consisted of 159 subjects (84 men and 75 women), who were assigned to one of 5 groups according to the following levels and types of their physical activity: physically inactive, physically active nonathletes, strength and power athletes, endurance athletes, and team sports athletes. Measurements were performed on the following knee flexor and extensor muscles of the dominant leg: rectus femoris, vastus medialis, vastus lateralis, biceps femoris, and semitendinosus. The results showed significant differences in contraction time—Tc (F = 1.911, p = 0.010) and delay time—Td (F = 1.989, p = 0.007) parameters between differently trained men and women, whereas in other TMG parameters, there were no differences between groups. It is indicated that physical activities characteristic of strength and power sports (combat sports and sprint disciplines) could lead to an increased speed of twitch force generation and fast twitch muscle fibers, and that almost any regular, systematic, and planned physical activity leads to increased muscle responsiveness. Obtained results also indicated that TMG parameters do not have enough specific discriminatory power for detecting differences between differently trained young adults.
Accentuated Eccentric Loading and Cluster Set Configurations in the Bench Press
Authors: Lates Alexandra D. , Greer Beau K. , Wagle John P. , Taber Christopher B.
Published: August 2020

Lates, AD, Greer, BK, Wagle, JP, and Taber, CB. Accentuated eccentric loading and cluster set configurations in the bench press. J Strength Cond Res 36(6): 1485–1489, 2022—This study was designed to examine the kinetic and kinematic differences between an Accentuated eccentric loading (AEL), traditional loading, and cluster sets in trained male subjects (age: 23.7 ± 4.0 years, height: 176.4 ± 2.8 cm, mass: 93.6 ± 7.0 kg) with lifting experience (training age: 7.2 ± 2.4 years, 1-repetition maximum (1RM) bench press: 125.0 ± 14.8 kg, relative strength ratio: 1.3 ± 0.1) in the bench press. Subjects reported for a total of 5 sessions which consisted of a 1RM testing session and 4 experimental trials. The 4 experimental conditions consisted of a traditional load (TRAD), traditional load with inter-repetition rest (TRDC), accentuated eccentric loading with inter-repetition rest (AELC), and Accentuated eccentric loading for the first repetition only (AEL1). Concentric load was 80% of subjects' 1RM for all conditions. An eccentric overload of 105% of 1RM was applied using weight-releasing hooks during the AEL conditions. TRDC demonstrated superior concentric outputs for mean velocity and mean power compared with TRAD, AELC, and AEL1 (p < 0.001). In addition, AEL1 produced significantly greater effects for rate of force development compared with TRDC (p < 0.001). These findings suggest that inter-repetition rest had an influence on concentric performance, specifically mean power and mean velocity, and may be favorable when using higher loads and when sustained power outputs are desired. In addition, AEL1 may provide a unique eccentric stimulus that alters loading parameters compared with traditional loading conditions.
Effects of Different Resistance Training Loads on the Muscle Quality Index in Older Women
Authors: Ribeiro Alex S. , Picoloto Alexandre , Nunes João Pedro , Bezerra Ewertton S. , Schoenfeld Brad J. , Cyrino Edilson S.
Published: August 2020

Ribeiro, AS, Picoloto, A, Nunes, JP, Bezerra, ES, Schoenfeld, BJ, and Cyrino, ES. Effects of different resistance training loads on the muscle quality index in older women. J Strength Cond Res 36(5): 1445–1449, 2022—The purpose of this study was to investigate the effects of resistance training (RT) performed using low vs. moderate loads on muscular strength, muscle mass, and muscle quality index (MQI) in older women. Twenty-seven older women (71.5 ± 5 years, 65.2 ± 11 kg, 154.2 ± 5 cm, and 27.4 ± 4 kg·m−2) were randomized into 2 groups: one that performed RT with a low load (LOW, n = 13) and another that performed RT with a moderate load (MOD, n = 14). An 8-week RT program was performed 3 d·wk−1. Outcomes included 1-repetition maximum (1RM) tests and assessment of body composition by dual-energy X-ray absorptiometry. The LOW load consisted of a relative load at 15RM, whereas the MOD load consisted of a relative load at 10RM. Both groups presented significant changes from pre-training to post-training for chest press 1RM (LOW = 10.3%, and MOD = 11.1%), knee extension 1RM (LOW = 14.4%, and MOD = 16.6%), preacher curl 1RM (LOW = 12.4%, and MOD = 12.0%), fat-free mass (LOW = 2.1%, and MOD = 1.9%), body fat (LOW = −3.2%, and MOD = −2.7%), and MQI (LOW = 10.6%, and MOD = 11.3%). Results were similar (p > 0.05) between groups. These findings suggest that LOW and MOD loads are equally effective for promoting improvements in muscular strength and muscle growth as well as the MQI in older women.
Positional Analysis of Body Composition Using Dual-Energy X-Ray Absorptiometry in National Collegiate Athletic Association Division I Football and Men's Lacrosse
Authors: Zabriskie Hannah A. , Dobrosielski Devon A. , Leppert Kyle M. , Droege Aaron J. , Knuth Nicolas D. , Lisman Peter J.
Published: August 2020

Zabriskie, HA, Dobrosielski, DA, Leppert, KM, Droege, AJ, Knuth, ND, and Lisman, PJ. Positional analysis of body composition using dual-energy X-ray absorptiometry in National Collegiate Athletic Association Division I football and men's lacrosse. J Strength Cond Res 36(6): 1699–1707, 2022—Despite the widespread use of dual-energy X-ray absorptiometry (DXA), few studies have examined differences in body composition between positions within sports and none have reported DXA-derived body composition reference values for men's lacrosse. The purpose of this study was to examine differences in measures of total and regional body composition and bone mineral density (BMD) using DXA across sport positions in a large cohort of National Collegiate Athletic Association Division I male lacrosse and football players. A total of 294 male athletes (football, n = 196; lacrosse, n = 98) underwent DXA. One-way analysis of variance or Kruskal-Wallis tests were used to examine whether body composition variables differed by sports position. In football, position was a significant determinant for every compositional variable in football athletes (all, p < 0.05; effect size range = 0.24–0.79). Offensive linemen had the highest total body fat percentage (30.1 ± 2.9%), followed by fullbacks (26.7 ± 3.3%) and defensive linemen (24.6 ± 5.7%); wide receivers had the lowest (14.5 ± 2.1%). For total body BMD, defensive linemen had the highest (1.70 ± 0.09 g·cm−3), followed by linebackers (1.67 ± 0.09 g·cm−3) and offensive linemen (1.65 ± 0.09 g·cm−3); kickers had the lowest (1.45 ± 0.11 g·cm−3) BMD. In lacrosse, no differences were found between positions for any total or regional body composition and BMD measure (all, p > 0.05). Our data confirm that total and regional measures of body composition and BMD vary across positions in football but not in men's lacrosse. Unlike football, similarities in body composition among lacrosse players may indicate that the uniformity of training demands or preferred player attributes in team selection outweigh the unique positional demands in gameplay.
Rate of Force Development Adaptations After Weightlifting-Style Training: The Influence of Power Clean Ability
Authors: James Lachlan P. , Suchomel Timothy J. , Comfort Paul , Haff G. Gregory , Connick Mark J.
Published: August 2020

James, LP, Suchomel, TJ, Comfort, P, Haff, GG, and Connick, M. Rate of force development adaptations after weightlifting-style training: the influence of power clean ability. J Strength Cond Res 36(6): 1560–1567, 2022—This experiment examined changes to the rate of force development (RFD) expressed under loaded jump conditions between individuals with a higher (stronger) and lower (weaker) weightlifting performance (as assessed by the 1 repetition maximum [RM] power clean) after training with the weightlifting derivatives. Two groups of markedly different weightlifting ability undertook 10 weeks of training with the power clean variants, snatch pulls, and jump squats across heavy and light conditions. Testing was performed at baseline, after 5 weeks of training (mid-test) and after training (post-test). During testing, RFD was assessed under a series of loads (20–80% squat 1RM) through the jump squat. Furthermore, the force-velocity relationship, and unloaded jump strategy (through the force-time curve waveform), were also examined. Very large change (Hedge's g, 95% confidence interval [g] = 2.10, 1.24 to 4.16) in RFD at 20% 1RM at mid-test occurred within the stronger group. Conversely, a small increase (g = 0.27, 0.53–1.91) among the weaker subjects existed in this measure at mid-test, reaching a moderate increase at post-test (g = 0.71, −0.18 to 2.15). Limited improvements were seen by the stronger subjects in RFD at 60 and 80% 1RM at either mid-test (60%: g = 0.27, −0.75 to 1.33; 80% = 0.02, −1.01 to 1.00) or post-test (60%: g = 0.52, −0.38 to 1.80; 80% = −0.26, −1.23 to 0.77). The stronger group experienced a shift throughout the force-velocity relationship while a more force-dominant adaptation occurred in weaker subjects. Differences in jump strategy between groups were also noted. Such training will elicit practically different adaptations in rapid force production depending on the individual's baseline weightlifting ability.
Daily Undulating Periodization Is More Effective Than Nonperiodized Training on Maximal Strength, Aerobic Capacity, and TCD4+ Cell Count in People Living With HIV
Authors: Soares Vitor Lopes , Soares Weverton Fonseca , Zanetti Hugo Ribeiro , Neves Fernando Freitas , Silva-Vergara Mário Leon , Mendes Edmar Lacerda
Published: August 2020

Soares, VL, Soares, WF, Zanetti, HR, Neves, FF, Silva-Vergara, ML, and Mendes, EL. Daily undulating periodization is more effective than nonperiodized training on maximal strength, aerobic capacity, and TCD4+ cell count in people living with HIV. J Strength Cond Res 36(6): 1738–1748, 2022—The aim of this study was to evaluate the effects of daily undulating periodization (DUP) and nonperiodized training (NPT) programs on maximal muscle strength, body composition, aerobic capacity, muscle power, and immune markers in people living with HIV (PLWHIV). A total of 41 PLWHIV were randomly assigned to control (CON [n = 15]), DUP (n = 13), and NPT (n = 13) groups. The DUP and NPT groups performed combined training 3 times a week on nonconsecutive days during 12 weeks, whereas the CON group was asked to maintain their current level of activity. After the 12-week training program, DUP produced greater gains in muscle strength (except for bench press), V̇o
2peak, and muscle power than NPT (p < 0.05). Compared to CON, the training groups showed significantly (p < 0.05) increased muscle strength (DUP = 31.0 ± 13.9 kg; NPT = 17.7 ± 9.2 kg; CON = −0.3 ± 1.5 kg), fat-free mass (DUP = 1.9 ± 1.5 kg; NPT = 1.4 ± 1.9 kg; CON = −0.1 ± 1.2 kg), and metabolic equivalent (DUP = 2.3 ± 1.3; NPT = 1.8 ± 1.9), and decreased body fat mass (DUP = −2.1 ± 1.6 kg; NPT = −1.4 ± 1.5 kg; CON = 0.1 ± 0.2) and functional aerobic impairment (DUP = −35.9 ± 17.0%; NPT = −25.8 ± 22.0%; CON = 0.8 ± 3.0%). There was an increase in TCD4+ cells only in the DUP group (p < 0.05). The training effect generally provided a positive correlation between change in leg press strength (r = 0.393, p < 0.05), triceps pulley strength (r = 0.417, p < 0.05), lat pull-down strength (r = 0.459, p < 0.05), and muscle power (r = 0.324, p < 0.05) with changing CD4 + lymphocyte count. Daily undulating periodization protocol showed to be safe, applicable, and more efficient for increasing strength, aerobic capacity, and TCD4+ cells compared to NPT in PLWHIV.
Investigating the Use of an Intermittent Sequential Pneumatic Compression Arm Sleeve for Recovery After Upper-Body Exercise
Authors: Cranston Adam W. , Driller Matthew W.
Published: August 2020

Cranston, AW and Driller, MW. Investigating the use of an intermittent sequential pneumatic compression arm sleeve for recovery after upper-body exercise. J Strength Cond Res 36(6): 1548–1553, 2022—The current study aimed to investigate the efficacy of an intermittent sequential pneumatic compression (ISPC) device placed on the arm after a fatiguing upper-body exercise circuit. Fifty resistance-trained athletes (37 males/13 females, mean ± SD; age = 27 ± 4 years) performed 3 physical performance tests (grip strength dynamometer, single-arm medicine ball throw, and preacher bench bicep curls to failure) before and after exercise, following a 30-minute recovery period. During the recovery period, subjects were randomly assigned an experimental arm, which was placed in the ISPC device, and a control arm (no device). Subjects completed a perceptual muscle soreness rating through palpation of 4 muscle groups in the upper body at the same time points and also 24 hours after recovery. There was a statistically significant interaction between conditions for the single-arm medicine ball throw (p < 0.01) in favor of the ISPC after the recovery period; however, the effect size was deemed trivial. There was a small but not statistically significant effect (d = 0.22, p > 0.05) for the bicep curls in favor of the ISPC and no significant difference for the grip strength (d = 0.09, p > 0.05). The perceptual muscle soreness scales resulted in significant differences between conditions immediately after and 24 hours after exercise across all muscle groups (p < 0.05), all in favor of the ISPC condition. This study supports the use of an upper-body ISPC device to reduce perceived muscle soreness for up to 24 hours after exercise, with negligible effects on physical performance when compared with a control trial.
Mechanical Differences Between Adolescents and Adults During Two Landing Phases of a Drop Jump Task
Authors: Moir Gavin L. , Munford Shawn N. , Snyder Brandon W. , Davis Shala E.
Published: August 2020

Moir, GL, Munford, SN, Snyder, BW, and Davis, SE. Mechanical differences between adolescents and adults during two landing phases of a drop jump task. J Strength Cond Res 36(4): 1090–1098, 2022—The mechanical differences between the first and second landing phases of a drop jump (DJ) task performed by adolescent and adult male players were investigated. Eleven adolescent basketball players (age: 16.5 ± 0.7 years) and 11 resistance-trained adults (age: 22.3 ± 1.9 years) performed DJs from a height of 0.40 m. Force plates and a 3-dimensional motion analysis system were used to determine mechanical variables, including landing velocity, normalized vertical stiffness, normalized peak impact force, and work as well as mechanical characteristics of the hip, knee, and ankle joints during the absorption phase of each landing. The adolescents produced greater peak impact forces (mean difference [

Diff] = 42 N·kg0.67; effect size [ES] = 1.15) and vertical stiffness (

Diff = 126 N·kg0.67·m−1; ES = 1.28) during shorter absorption phases (

Diff = 0.09 seconds; ES = 2.67) compared with the adults, despite their lower landing velocities (

Diff = 0.21 m·s−1; ES = 1.37). Furthermore, the adolescents generated greater peak extensor joint moments at the lower-body joints compared with the adults (

Diff = 2.3 N·m·kg0.67; ES = 1.17), but they did not effectively modulate the energy absorbed by the joint moments in response to the changing demands of the landing tasks. The assessment of the biomechanical characteristics of the 2 landing phases associated with a DJ task revealed that adolescent male basketball players adopt neuromuscular strategies that may increase the risk of incurring musculoskeletal injuries compared with resistance-trained adults.
Ergogenic Effects of 8 Days of Sceletium Tortuosum Supplementation on Mood, Visual Tracking, and Reaction in Recreationally Trained Men and Women
Authors: Hoffman Jay R. , Markus Irit , Dubnov-Raz Gal , Gepner Yftach
Published: August 2020

Hoffman, JR, Marcus, I, Dubnov-Raz, G, and Gepner, Y. Ergogenic effects of 8 days of Sceletium tortuosum supplementation on mood, visual tracking, and reaction in recreationally trained men and women. J Strength Cond Res 34(9): 2476–2481, 2020—Sceletium tortuosum (ST) is a South African plant that has been reported to promote a sense of well-being in healthy individuals and used in treating people with anxiety, stress, or depression. These studies have been conducted in middle-aged and older adults, but no investigations have been performed in a healthy, young adult population. Thus, the purpose of this study was to examine the effect of 8 days of ST extract (25-mg) supplementation on changes in reactive agility, visual tracking, and mood. Sixty recreationally trained men (n = 48) and women (n = 12), between 20 and 35 years, were randomly assigned to 1 of 2 groups: ST or placebo (PL). Subjects were tested on 2 occasions: before supplementation and 2-hours after supplementation on day 8. Subjects completed a subjective questionnaire to assess alertness and energy using a visual analog scale (VAS). In addition, subjects completed the Profile of Mood States questionnaire and performed reactive agility and visual tracking assessments. Significant improvements were noted for ST in complex reactive performance that required subjects to respond to repeated visual stimuli with a cognitive load compared with PL. However, no significant changes were noted between the groups in either VAS or total mood score. In addition, no differences were observed in simple reaction assessments. The results of this study demonstrate an ergogenic benefit in complex reactive tasks that include a cognitive load. However, in this subject population studied, no benefits in mood were observed.
Countermovement Jump Standards in Rugby League: What is a “Good” Performance?
Authors: McMahon John J. , Lake Jason P. , Dos'Santos Thomas , Jones Paul A. , Thomasson Michael L. , Comfort Paul
Published: August 2020

McMahon, JJ, Lake, JP, Dos'Santos, T, Jones, PA, Thomasson, ML, and Comfort, P. Countermovement jump standards in rugby league: what is a “good” performance? J Strength Cond Res 36(6): 1691–1698, 2022—The countermovement jump (CMJ) is considered an important test in rugby league, and the force platform is the recommended tool for assessing CMJ performance in this cohort. Because of inconsistent methods applied across previous studies, there is currently a lack of understanding of what constitutes a “good” CMJ performance, with respect to the typical CMJ metrics that are reported for rugby league players. The purpose of this study was, therefore, to produce a scale of reference values for the jump height (JH), reactive strength index modified (RSImod), and mean (PPmean) and peak (PPpeak) propulsion power (relative to body mass) for top-level senior rugby league players competing in the global “forward” and “back” positional groups. One hundred four players (55 forwards and 49 backs) from the top 2 tiers of English rugby league performed 3 CMJs on a force platform at the beginning of pre-season training. The JH, RSImod, PPmean, and PPpeak were calculated using criterion methods, and a scale of norm-referenced values (percentiles) was produced for each positional group. The backs outperformed the forwards for each CMJ metric reported, thus supporting the production of position-specific norm-referenced values. When each positional group was separated into quartile subgroups, the respective JH, RSImod, PPmean, and PPpeak values were mostly largely and significantly different both within and between positions. The presented scale of reference values can, therefore, be used to determine the performance standards of rugby league forwards and backs with respect to the most commonly reported CMJ-derived variables for this cohort.
Effect of Divergent Solar Radiation Exposure With Outdoor Versus Indoor Training in the Heat: Implications for Performance
Authors: O'Connor Fergus K. , Doering Thomas M. , Minett Geoffrey M. , Reaburn Peter R. , Bartlett Jonathan D. , Coffey Vernon G.
Published: August 2020

O'Connor, FK, Doering, TM, Minett, GM, Reaburn, PR, Bartlett, JD and Coffey, VG. Effect of divergent solar radiation exposure with outdoor versus indoor training in the heat: implications for performance. J Strength Cond Res 36(6): 1622–1628, 2022—The aim of this study was to determine physiological and perceptual responses and performance outcomes when completing high-intensity exercise in outdoor and indoor hot environments with contrasting solar radiation exposure. Seven cyclists and 9 Australian Football League (AFL) players undertook cycling trials in hot conditions (≥30 °C) outdoors and indoors. Cyclists completed 5 × 4 minutes intervals (∼80% peak power output [PPO]) with 2 minutes recovery (∼40% PPO) before a 20-km self-paced ride. Australian Football League players completed a standardized 20 minutes warm-up (∼65% mean 4-minute power output) then 5 × 2 minutes maximal effort intervals. Heart rate (HR), PO, ratings of perceived exertion (RPE), thermal comfort (TC), and thermal sensation (TS) were recorded. Core (Tc) and skin temperature (Tsk) were monitored in cyclists alone. In both studies, ambient temperature, relative humidity, and solar radiation were monitored outdoors and matched for ambient temperature and relative humidity indoors, generating different wet bulb globe temperature (WBGT) for cyclists, but the similar WBGT for AFL players through higher relative humidity indoors. The statistical significance was set at p ≤ 0.05. Cyclists' HR (p = 0.05), Tc (p = 0.03), and Tsk (p = 0.03) were higher outdoors with variable effects for increased RPE, TS, and TC (d = 0.2–1.3). Power output during intervals was not different between trials, but there were small-moderate improvements in cyclists' PO and 20-km time indoors (d = 0.3–0.6). There was a small effect (d = 0.2) for AFL players' mean PO to increase outdoors for interval 4 alone (p = 0.04); however, overall there were small-moderate effects for lower RPE and TS indoors (d = 0.2–0.5). Indoor training in hot conditions without solar radiation may promote modest reductions in physiological strain and improve performance capacity in well-trained athletes.
Anaerobic Threshold in Stand-up Paddle: Comparison Between Direct and Alternative Methods
Authors: Balikian Pedro , Marinho Alisson H. , Gomes de Araujo Gustavo , Prado Eduardo S. , Mendes Eduardo V. , Ryan Geraldes Amândio A.
Published: August 2020

Balikian, P, Gomes de Araujo, G, Prado, ES, Ryan Geraldes, AA, Marinho de Lima, AH, and Mendes, EV. Anaerobic threshold in stand-up paddle: comparison between direct and alternative methods. J Strength Cond Res 36(7): 1896–1900, 2022—The purpose of this study was to test the validity of alternative protocols, mean velocity during 30 minutes of continuous effort (V30min) and critical velocity (CV), to estimate the anaerobic threshold in stand-up paddle (SUP). Eight athletes performed: 3 maximal efforts at 400-, 500-, and 800-m distances to determine CV values, using the distance-time relationship; 3 efforts at 85, 90, and 100% of maximal 500-m effort to determine the velocity related to 3.5 mmol·L−1 of lactate, assumed as the onset of blood lactate accumulation (OBLA) and; a 30-minute continuous effort to determine the V30min. All evaluations were separated by 48 hours, with the athletes using their own boards and paddles in the water. No differences were observed between the OBLA (2.35 ± 0.13 m·s−1) and alternative methods (CV: 2.42 ± 0.20 m·s−1; p = 0.10 and V30min: 2.32 ± 0.13 m·s−1; p = 0.63). Although strong correlations were observed between the OBLA and alternative methods (CV: r = 0.84 and V30min: r = 0.94), the limits of agreement were higher in CV (±0.23 m·s−1) than V30min (±0.08 m·s−1). These results demonstrate that both the CV and V30min are valid to estimate the OBLA. In view of the specificity of SUP and the high levels of agreement, the use of the V30min is recommended to prescribe training intensities.
Muscle Activity, Leg Stiffness, and Kinematics During Unresisted and Resisted Sprinting Conditions
Authors: Zabaloy Santiago , Carlos-Vivas Jorge , Freitas Tomás T. , Pareja-Blanco Fernando , Loturco Irineu , Comyns Thomas , Gálvez-González Javier , Alcaraz Pedro E.
Published: August 2020

Zabaloy, S, Carlos-Vivas, J, Freitas, TT, Pareja-Blanco, F, Loturco, I, Comyns, T, Gálvez-González, J, and Alcaraz, PE. Muscle activity, leg stiffness and kinematics during unresisted and resisted sprinting conditions. J Strength Cond Res 36(7): 1839–1846, 2022—This study aimed to compare muscle activity, leg stiffness, and kinematics (contact and flight time [FT], stride length and frequency, and trunk angle [TA]) of unloaded sprinting to resisted sprint (RST) using different loads. Twelve male rugby players (age: 23.5 ± 5.1 years; height: 1.79 ± 0.04 m; body mass 82.5 ± 13.1 kg) performed 30-m sprints using different loading conditions (0, 10, 30 and 50% of velocity loss—Vloss—from the maximum velocity reached under unloaded condition). Muscle activity from 4 muscles (biceps femoris long head, rectus femoris [RF], gluteus medius and gastrocnemius), leg stiffness (Kleg), and kinematics were measured during the acceleration and maximum velocity (Vmax) phases of each sprint. Heavier loads led to significantly lower biceps femoris long head activation and higher rectus femoris activity (p < 0.01–0.05). Significant reductions in Kleg were observed as loading increased (p < 0.001–0.05). Kinematic variables showed substantial changes with higher loads during the acceleration and Vmax phase. In conclusion, the heavier the sled load, the higher the disruptions in muscle activity, Kleg, and kinematics. When coaches and practitioners intend to conduct resisted sprint training sessions without provoking great disruptions in sprint technique, very-heavy sled loads (greater than 30% Vloss) should be avoided. However, heavy sled loads may allow athletes to keep specific positions of the early acceleration phase for longer time intervals (i.e., first 2–3 strides during unresisted sprints).
Isometric Mid-thigh Pull Kinetics: Sex Differences and Response to Whole-Body Vibration
Authors: Merrigan Justin J. , Dabbs Nicole C. , Jones Margaret T.
Published: August 2020

Merrigan, JJ, Dabbs, NC, and Jones, MT. Isometric mid-thigh pull kinetics: Sex differences and response to whole-body vibration. J Strength Cond Res 34(9): 2407–2411, 2020—The purpose was to investigate whether whole-body vibration's (WBV's) effect on force-time characteristics is dependent on time and sex. Subjects (men, n = 18; women, n = 18) performed a static quarter squat with WBV (frequency: 30 Hz; amplitude: 2–4 mm) and without for 5 × 30 seconds repetitions (1:1, WBV:rest). Next, they performed 2 sets of 3 repetitions of the isometric mid-thigh pull (IMTP) with 3 minutes of intraset rest and 5 minutes of interset rest. Peak force (PF) and rate of force development (RFD) from 0 to 50, 0 to 150, and 0 to 250 milliseconds (RFD50, RFD150, and RFD250) were analyzed (p < 0.05). A significant effect of condition existed for PF (p = 0.019) and RFD from 0 to 250 seconds (p = 0.031). In women, RFD was moderately affected immediately post-WBV (p = 0.070; d = 0.49). Yet in men, the effect of WBV on RFD existed 15 minutes after exposure (p = 0.017; d = 0.36). In absolute terms men produced more PF than women (1,008.6 ± 289.7 N; p < 0.001). All RFD bands were greater in men than those of women (RFD50, 5,519.3 ± 2,927.2 N·s−1; RFD150, 3,361.4 ± 1,385.3 N·s−1; RFD250, 2,505.7 ± 867.1 N·s−1; p < 0.05). However, relative to fat-free mass, PF in men (40.1 ± 7.2 N·kg−1) was not different from women (37.7 ± 6.4 N·kg−1; p = 0.284). The same was true for RFD150 (21.1 ± 24.1 N·kg−1·s−1; p = 0.084) and RFD250 (10.9 ± 14.1 N·kg−1·s−1; p = 0.128). Yet, RFD50 remained greater in men (139.1 ± 33.6 N·kg−1·s−1) than that of women (86.8 ± 34.5 N·kg−1·s−1; p = 0.034). Current WBV protocols resulted in trivial to moderate effects on IMTP forces, which may be dependent on sex and time. Finally, it is recommended that women complete movements with the intent to move weight quickly to improve early RFD.
Effectiveness of a 2-Week Strength Training Learning Intervention on Self-selected Weight-Training Intensity
Authors: Glass Stephen C. , Ahmad Sabrina , Gabler Taylor
Published: August 2020

Glass, SC, Ahmad, S, and Gabler, T. Effectiveness of a 2-week strength training learning intervention on self-selected weight-training intensity. J Strength Cond Res 34(9): 2443–2448, 2020—The purpose of this study was to determine the effectiveness of an imposed (IM) vs. self-selected (SS) 2-week strength training intervention on SS resistance training intensity. Subjects 18–40 years (SS n = 10 and IM n = 10) were provided resistance training orientation (chest press, leg press, triceps extension, bicep curl, and shoulder press). On 6 different training days, subjects completed 2 sets on each machine while blinded to the load. The SS group SS loads without any intensity or effort feedback. Load, repetitions, and ratings of perceived exertion (RPE) were recorded. The IM group was encouraged to lift to fatigue, and if they exceeded 12 repetitions, subsequent load was increased (goal-attain 70% one repetition maximum [1RM]). After training, SS and IM SS loads and repetitions for all lifts, plus 3 novel lifts (pec fly, leg extension, and shoulder raise). One repetition maximum was assessed last. Comparisons between groups were made using 2-way analysis of variance. There were significant main effects for % 1RM for the condition and day (day 1 IM = 57.2 ± 12.0%, SS = 47.2 ± 13.7% and day 6 IM = 74.7 ± 10.8%, SS = 66.2 ± 13.4%). There were significant effects across days for reps (day 1 IM = 10.8 ± 4.8, SS = 12.3 ± 4.0 and day 6 IM = 9.3 ± 3.6, SS = 10.0 ± 3.0) and RPE (day 1 = 15.4 ± 2.0 and day 6 = 16.5 ± 1.9). For both SS and IM post-training SS loads exceeded 60% 1RM. However, among the novel lifts, only the pec fly was greater than 60% 1RM (pec fly 63.0 ± 11.0%, leg extension 39.8 ± 12.5%, and shoulder raise 53.1 ± 12.8%). Two weeks of supervised resistance training resulted in both IM and SS self-selecting loads greater than 60% 1RM. There were no differences after 2-weeks of training between IM load and SS load groups.
Performance Differences Between the Arched and Flat Bench Press in Beginner and Experienced Paralympic Powerlifters
Authors: Ribeiro Neto Frederico , Dorneles Jefferson R. , Luna Rafael M. , Spina Murilo A. , Gonçalves Carlos W. , Gomes Costa Rodrigo R.
Published: August 2020

Neto, FR, Dorneles, JR, Luna, RM, Spina, MA, Gonçalves, CW, and Gomes Costa, RR. Performance differences between the arched and flat bench press in beginner and experienced Paralympic powerlifters. J Strength Cond Res 36(7): 1936–1943, 2022—The present study aimed to verify the differences of the total load, trajectory of the barbell in the sagittal plane, and mean velocity of the barbell between the arched and flat techniques of the bench press in beginner (BG) and experienced (EG) Paralympic powerlifters. Twenty beginners (age: 34.4 years; experience: 3.3 months) and 23 experienced (age: 35.5 years; experience: 9.8 months) Paralympic powerlifters were selected from a Rehabilitation Hospital Network and a Paralympic sports center. Subjects were assessed in the one-maximum repetition test of the bench press exercise using the flat and arched bench press techniques (48–72-hour interval between sessions). Maximum strength, trajectory of the barbell in the sagittal plane, and mean velocity of the barbell were measured to compare the techniques and the groups. The total load corrected with the Haleczko formula was significantly higher in EG compared with BG (∆ = 21.1%; effect sizes [ES] = 0.39, p ≤ 0.05). There were no significant differences for all analyzed outcomes comparing the arched and flat techniques. During the eccentric phase of the bench press, all assessed differences ranged from −16.6 to 23.1% and presented ES of trivial to moderate. On the concentric phase, the assessed differences ranged from −20.7 to 13.9% and presented ES of trivial to moderate. The total load, trajectory of the barbell in the sagittal plane, and mean velocity of the barbell were not significantly different between the arched and flat techniques for experienced and beginner powerlifting athletes during both the eccentric and concentric phase of the movement. However, further analyses are essential to determine the best technique for athletes.