Effects of Integrative Neuromuscular Training and Detraining on Countermovement Jump Performance in Youth Volleyball Players
Nunes, ACCA, Cattuzzo, MT, Faigenbaum, AD, and Mortatti, AL. Effects of integrative neuromuscular training and detraining on countermovement jump performance in youth volleyball players. J Strength Cond Res 35(8): 2242–2247, 2021—The purpose of this study was to analyze the effect of integrative neuromuscular training (INT) on countermovement vertical jump height (CVJH) performance in youth volleyball players before and after a detraining period. Thirty-two novice volleyball players were cluster randomized into 2 groups: intervention group—INT (age: 13.1 ± 0.4 years; body mass: 55.3 ± 12.1 k...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Neuromuscular Jumping Performance and Upper-Body Horizontal Power of Volleyball Players
Gonçalves, CA, Lopes, TJD, Nunes, C, Marinho, DA, and Neiva, HP. Neuromuscular jumping performance and upper-body horizontal power of volleyball players. J Strength Cond Res 35(8): 2236–2241, 2021—The aim of the current study was to characterize the neuromuscular jumping performance and upper-body horizontal power of elite and subelite volleyball players. In addition, those neuromuscular performances were compared between field positions. One hundred twenty-two male volleyball players participated in the study: 83 elite players (mean ± SD: 24.11 ± 5.57 years) and 39 subelite players (25.38 ...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Plyometric Training Improves Not Only Measures of Linear Speed, Power, and Change-of-Direction Speed But Also Repeated Sprint Ability in Young Female Handball Players
In conclusion, a short-term in-season PT program, in replacement of handball-specific drills, is effective in improving measures of physical fitness (i.e., linear/CoD speed, jumping, and RSA) in young female handball players. (Source: Journal of Strength and Conditioning Research)
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Exercise Response to Real Combat in Elite Taekwondo Athletes Before and After Competition Rule Changes
In conclusion, after competition rule changes, there has been a shift in taekwondo combat profile toward greater body movement dynamics, higher intensity, and greater postexercise fatigue. The values of key indices of exercise response (mechanical activity, HR, EE, and lactate concentration) during tournaments are near or exceeding the maximum attained during progressive exercise until exhaustion. Therefore, more focus is needed on taekwondo-specific high-intensity training and postcombat recovery to adapt athletes to increased competition requirements. (Source: Journal of Strength and Conditioning Research)
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Lactate Concentration Is Related to Skin Temperature Variation After a Specific Incremental Judo Test
This study aimed to analyze the skin temperature (tsk) response in judokas after a specific incremental test and to determine whether anthropometric and physiological measures can be explained by the variation in mean tsk. A total of 23 male judo athletes (age: 20.1 ± 4.7 years; height: 173.1 ± 8.1 cm; and body mass: 71.7 ± 8.1 kg) performed a specific incremental judo test. Skin temperature evaluations were collected in 26 regions of interest (ROIs), and the mean tsk was calculated using an equation including 10 of them. The time points before the test (pre-test), immediately after (0 minutes), and af...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Resisted Sprint Training in Youth: The Effectiveness of Backward vs. Forward Sled Towing on Speed, Jumping, and Leg Compliance Measures in High-School Athletes
We examined the effects of FRS and backward RS (BRS) and compared these with a traditional physical education curriculum (CON). One hundred fifteen boys (age 13–15 years) were matched for maturity and allocated to either an FRS (n = 34), BRS (n = 46), or CON (n = 35) group. Training groups towed progressively overloaded sleds (20–55% body mass) 2 d·wk−1 for 8 weeks. Pre-training and post-training data were collected for sprinting times over 10 and 20 m, countermovement jump (CMJ) height, and leg stiffness (KN). Performance remained unchanged for the CON group (all p> 0.05), whereas all variables...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Effect of the Growth Spurt on Training of Strength and Power During Mid-Adolescence in Boys
This study determined if the growth spurt will influence the training of strength and power in boys (N = 86) of differing maturity levels. Based on a 2-group, pretest posttest design within a 2 school-year follow-up period, including 4 time point measurements, an experimental group (EG), who participated in different school sports were subjected to an additional 6 months, strength and power training program, twice a week for 45 minutes over 2 consecutive years (n = 47, 13.67 ± 0.26 years). They were compared with boys (n = 39, 13.68 ± 0.16 years) serving as a control group (CG) for normal growth who did not c...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Ischemic Preconditioning and Muscle Force Capabilities
This study analyzed the effects of ischemic preconditioning (IPC) on muscle force capabilities. Sixteen male subjects participated in this randomized, crossover, sham-controlled study. They were assigned to either IPC (3 × 5 minutes at 220 mm Hg in both arms with 5-minute rests) or a sham intervention (SHAM) (occlusion pressure set at 10 mm Hg). Forty minutes later, their force capabilities on the bench press exercise were assessed (load-velocity relationship with light, moderate, and heavy loads [30, 50, and 70% body mass, respectively]; 1 repetition maximum [1RM]; and number of repetitions to failure in 3 sets with...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Factors Underlying Bench Press Performance in Elite Competitive Powerlifters
Reya, M, Škarabot, J, Cvetičanin, B, and Šarabon, N. Factors underlying bench press performance in elite competitive powerlifters. J Strength Cond Res 35(8): 2179–2186, 2021—Previous investigations of 1 repetition maximum bench press (1RM BP) performance have been either descriptive or have explored a limited number of contributing variables. The purpose of this study was to investigate the interplay between structural, technical, and neuromuscular factors in relation to 1RM BP in competitive powerlifters. Thirteen national and international level male powerlifters (26 ± 9 years, 178 &plus...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Concurrent Validity of Field-Based Diagnostic Technology Monitoring Movement Velocity in Powerlifting Exercises
In conclusion, different technologies should not be used interchangeably. Practitioners who require negligible measurement error in their assessment of movement velocity are advised to use linear position transducers over inertial sensors. (Source: Journal of Strength and Conditioning Research)
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Examining the Accuracy of the Polar A360 Monitor
Rider, BC, Conger, SA, Ditzenberger, GL, Besteman, SS, Bouret, CM, and Coughlin, AM. Examining the accuracy of the Polar A360 monitor. J Strength Cond Res 35(8): 2165–2169, 2021—The purpose of this study was to determine the accuracy of the Polar A360 heart rate (HR) monitor during periods of rest, walking/running, and active/passive recovery from exercise. Thirty collegiate athletes (women n = 15 and men n = 15) wore an A360 monitor and a previously validated chest HR monitor (Polar RS400) that served as the criterion measurement across a range of resting and walking/running intensities. First, subjects rested...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Acute Leg and Trunk Muscle Fatigue Differentially Affect Strength, Sprint, Agility, and Balance in Young Adults
Roth, R, Donath, L, Zahner, L, and Faude, O. Acute leg and trunk muscle fatigue differentially affect strength, sprint, agility, and balance in young adults. J Strength Cond Res 35(8): 2158–2164, 2021—How important leg or trunk muscles are for balance and sprint performance is still unexplored. Therefore, we separately fatigued the leg and trunk musculature and examined their contribution to strength, balance, sprint, and agility performance. Twenty-four healthy adults (12 women; age 22.9 [SD: 2.6] years; body mass 59 [10] kg; height 1.65 [0.09] m; and 12 men; age 22.7 [3.0] years; body mass 78 [9] kg; height 1...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Evaluation of Training Load During Suspension Exercise
Giancotti, GF, Fusco, A, Varalda, C, Capelli, G, and Cortis, C. Evaluation of training load during suspension exercise. J Strength Cond Res 35(8): 2151–2157, 2021—The aims of this study were to evaluate body inclination and ground reaction force and to predict equations to estimate the training load distribution during suspension training (ST) static back-row at different lengths of the straps. Thirty volunteers (men = 16 and women = 14; age = 23.3 ± 1.7 years; body mass = 63.9 ± 13.3 kg; height = 167.9 ± 9.2 cm; body mass index [BMI] = 22.5 ± 3.4 kg·m−2) performed 14 st...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Downhill Running Impairs Activation and Strength of the Elbow Flexors
Brandenberger, KJ, Warren, GL, Ingalls, CP, Otis, JS, and Doyle, JA. Downhill running impairs activation and strength of the elbow flexors. J Strength Cond Res 35(8): 2145–2150, 2021—The purpose of this study was to determine if knee extensor injury induced by 1 hour of downhill running attenuated force production in the elbow flexors. Subjects completed either downhill running for 1 hour (injured group; n = 6) or sedentary behavior (control group; n = 6). Strength and voluntary activation (%VA) were measured by isometric twitch interpolation of the elbow flexor and knee extensor muscles at the following time p...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Biomechanical Effects of a 6-Week Change-of-Direction Technique Modification Intervention on Anterior Cruciate Ligament Injury Risk
Dos'Santos, T, Thomas, C, Comfort, P, and Jones, PA. Biomechanical effects of a 6-week change-of-direction technique modification intervention on anterior cruciate ligament injury risk. J Strength Cond Res 35(8): 2133–2144, 2021—The aim of this study was to evaluate the biomechanical effects of a 6-week change-of-direction (COD) technique modification intervention on anterior cruciate ligament (ACL) injury risk (i.e., multiplanar knee joint loads) during 45° (CUT45) and 90° (CUT90) side-step cutting. A nonrandomized, controlled 6-week intervention study was administrated. Fifteen male multidirectional s...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Acute Effect of Repeated Sprints on Interlimb Asymmetries During Unilateral Jumping
Bishop, C, McAuley, W, Read, P, Gonzalo-Skok, O, Lake, J, and Turner, A. Acute effect of repeated sprints on interlimb asymmetries during unilateral jumping. J Strength Cond Res 35(8): 2127–2132, 2021—The aim of this study was to investigate the effects of multiple repeated sprints on unilateral jump performance and interlimb asymmetries. Eighteen recreationally active men performed 3 single-leg countermovement jumps (SLCMJ) as baseline data. The repeated sprint protocol was 6 × 40 m with 20 seconds of passive rest between each sprint. This protocol was conducted 4 times, each set separated by 4 minutes o...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Effect of Bench Press Load Knowledge on One Repetition Maximum Strength
Snarr, RL, Adams, K, and Cook, J. Effect of bench press load knowledge on one repetition maximum strength. J Strength Cond Res 35(8): 2121–2126, 2021—Knowledge of a given load and visual feedback are crucial while performing a given task. Although previous literature has examined the consequences of lifting a submaximal weight, the removal of load knowledge has yet to be examined under maximal effort. Therefore, the purpose of this investigation was to examine the differences in 1 repetition maximum (1RM) bench press values between a known and unknown external load. Twenty resistance-trained subjects (10 male s...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Effects of Different Intraset Rest Durations on Lifting Performance and Self-perceived Exertion During Bench Press Exercise
This study compared the number of successful repetitions, failure rates, and ratings of perceived exertion (RPEs) among intraset rest (ISR) protocols (0-, 20-, or 40-second rest between third and fourth repetitions) during bench press exercise with total 3 sets and 6 repetitions per set at 6 repetition maximum (6RM) load. Thirty-four college-aged men performed 6RM loads with ISR 0, 20, and 40 on 3 separate visits in a counterbalanced order while the total rest time and duration of each protocol was equated. Results showed failure rates of 32.4% for ISR0 (11 subjects with failed repetition), 14.7% for ISR20, and 2.9% for IS...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Molecular Differences in Skeletal Muscle After 1 Week of Active vs. Passive Recovery From High-Volume Resistance Training
Vann, CG, Haun, CT, Osburn, SC, Romero, MA, Roberson, PA, Mumford, PW, Mobley, CB, Holmes, HM, Fox, CD, Young, KC, and Roberts, MD. Molecular differences in skeletal muscle after 1 week of active vs. passive recovery from high-volume resistance training. J Strength Cond Res 35(8): 2102–2113, 2021—Numerous studies have evaluated how deloading after resistance training (RT) affects strength and power outcomes. However, the molecular adaptations that occur after deload periods remain understudied. Trained, college-aged men (n = 30) performed 6 weeks of whole-body RT starting at 10 sets of 10 repetitions per exerci...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Effects of Interlimb Asymmetries on Acceleration and Change of Direction Speed: A Between-Sport Comparison of Professional Soccer and Cricket Athletes
Bishop, C, Read, P, Brazier, J, Jarvis, P, Chavda, S, Bromley, T, and Turner, A. Effects of interlimb asymmetries on acceleration and change of direction speed: a between-sport comparison of professional soccer and cricket athletes. J Strength Cond Res 35(8): 2095–2101, 2021—The first aim of this study was to quantify and compare asymmetries among professional soccer and cricket athletes. The second aim was to examine the association between asymmetries and performance within both groups. Professional soccer (n = 18) and cricket (n = 23) athletes performed single-leg countermovement jumps, single-leg drop jumps...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Influence of High- and Low-Frequency Resistance Training on Lean Body Mass and Muscle Strength Gains in Untrained Men
Franco, CMC, Carneiro, MAS, de Sousa, JFR, Gomes, GK, and Orsatti, FL. Influence of high- and low-frequency resistance training on lean body mass and muscle strength gains in untrained men. J Strength Cond Res 35(8): 2089–2094, 2021—The aim of this study was to investigate whether high-frequency resistance training (HFRT) performs better in lean body mass (LBM) and muscle strength gains when compared with low-frequency resistance training (LFRT). Eighteen untrained males (height: 1.76 ± 0.05 m, body mass: 78.3 ± 13.5 kg, and age: 22.1 ± 2.2 years) were randomly allocated into HFRT (n = 9) a...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Blood Flow Restriction Does Not Attenuate Short-Term Detraining-Induced Muscle Size and Strength Losses After Resistance Training With Blood Flow Restriction
Teixeira, EL, de Salles Painelli, V, Silva-Batista, C, de Souza Barros, T, Longo, AR, Lasevicius, T, Schoenfeld, BJ, Aihara, AY, and de Almeida Peres, B. Blood flow restriction does not attenuate short-term detraining-induced muscle size and strength losses after resistance training with blood flow restriction. J Strength Cond Res 35(8): 2082–2088, 2021—After a short-term resistance training with blood flow restriction (BFR), we investigated the effects of 12 days of detraining (DET), without an exercise stimulus, on quadriceps cross-sectional area (QCSA) and muscle strength (1 repetition maximum [1RM]), with 1...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Predicting Loading Intensity Measuring Velocity in Barbell Hip Thrust Exercise
This study aimed to assess the relationship between mean velocity (MV) and mean propulsive velocity (MPV) at different relative training loads (%1RM) in the barbell hip thrust exercise. One hundred two male sport science students performed an incremental 1RM testing protocol for the barbell hip thrust exercise, and a linear position transducer measured MV and MPV of the barbell. The 1RM was reached at 0.25 ± 0.03 m·s−1, and the regression model generated to estimate a relative load showed an acceptable standard error of estimate (7.01 ± 1.05% 1RM and 7.36 ± 1.05% 1RM for MV and MPV, respec...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Endocrine and Body Composition Changes Across a Competitive Season in Collegiate Speed-Power Track and Field Athletes
Mangine, GT, Eggerth, A, Gough, J, Stratton, MT, Feito, Y, and VanDusseldorp, TA. Endocrine and body composition changes across a competitive season in collegiate speed-power track and field athletes. J Strength Cond Res 35(8): 2067–2074, 2021—Maintaining lean mass is important for track and field (TF) athletes who compete in speed-power events, but little is known about how lean mass and related hormones might change over an 8- to 10-month collegiate season. Therefore, to monitor changes in free testosterone (T), cortisol (C), and body composition in TF athletes across their entire competitive season, 9 female...
Source: Journal of Strength and Conditioning Research - August 1, 2021 Category: Sports Medicine Tags: Research Notes Source Type: research

Effects of Plyometric Jump Training on Electromyographic Activity and Its Relationship to Strength and Jump Performance in Healthy Trained and Untrained Populations: A Systematic Review of Randomized Controlled Trials
In conclusion, PJT may improve muscle activation during the performance of strength and jumping tasks. However, conflicting results were observed probably arising from (a) studies that incorporated a large number of outcomes with reduced sensitivity to PJT, (b) methodological limitations associated to muscle activation measurement during strength and jumping tasks, and (c) limitations associated with PJT prescription. Future studies in this field should strive to solve these methodological shortcomings. (Source: Journal of Strength and Conditioning Research)
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Brief Review Source Type: research

Individualized and Fixed Thresholds to Demarcate PlayerLoad Intensity Zones Produce Different Outcomes
Scanlan, AT, Fox, JL, Milanović, Z, Stojanović, E, Stanton, R, and Dalbo, VJ. Individualized and fixed thresholds to demarcate PlayerLoad intensity zones produce different outcomes. J Strength Cond Res 35(7): 2046–2052, 2021—Individualized approaches to derive intensity zones are yet to be examined using microsensor metrics in basketball. The purpose of this study was to quantify and compare the time spent in different PlayerLoad intensity zones using individualized and fixed approaches during basketball training. Thirteen semiprofessional, male basketball players were monitored across the preparatory trainin...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Research Note Source Type: research

Dribble Deficit Enables Measurement of Dribbling Speed Independent of Sprinting Speed in Collegiate, Male, Basketball Players
Ramirez-Campillo, R, Gentil, P, Moran, J, Dalbo, VJ, and Scanlan, AT. Dribble Deficit enables measurement of dribbling speed independent of sprinting speed in collegiate, male, basketball players. J Strength Cond Res 35(7): 2040–2045, 2021—The aim of this study was to determine the relationships between sprinting and dribbling speed in basketball during linear and change-of-direction (COD) sprints using total dribbling time and Dribble Deficit. Collegiate, male, basketball players (n = 10; 21.0 ± 1.6 years) performed linear and COD sprints with and without dribbling a ball. Linear dribbling sprints were ...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Effects of Different Periodization Strategies of Combined Aerobic and Strength Training on Heart Rate Variability in Older Women
Rodrigues, JAL, Santos, BC, Medeiros, LH, Gonçalves, TCP, and Júnior, CRB. Effects of different periodization strategies of combined aerobic and strength training on heart rate variability in older women. J Strength Cond Res 35(7): 2033–2039, 2021—The preservation of autonomic function has been proposed to be a key determinant of health and longevity. Periodization in combined training (CT) (strength plus aerobic exercise in the same session) might improve autonomic modulation. However, the specific influences of nonperiodized (NP), flexible nonlinear periodized (FNLP), and nonlinear periodized (N...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Training Experience and Maturational, Morphological, and Fitness Attributes as Individual Performance Predictors in Male and Female Under-14 Portuguese Elite Basketball Players
In conclusion, the results of this study indicate that around puberty, physical fitness attributes of elite basketball players of both sexes are associated with game performance parameters. Two regression models have been estimated to predict the performance of youth basketball players of both genders. (Source: Journal of Strength and Conditioning Research)
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Differences in Acceleration and High-Intensity Activities Between Small-Sided Games and Peak Periods of Official Matches in Elite Soccer Players
Dalen, T, Sandmæl, S, Stevens, TGA, Hjelde, GH, Kjøsnes, TN, and Wisløff, U. Differences in acceleration and high-intensity activities between small-sided games and peak periods of official matches in elite soccer players. J Strength Cond Res 35(7): 2018–2024, 2021—The purpose of this study was to compare whether the physical performance of players during 4 vs. 4 + goalkeeper (4 vs. 4) and 6 vs. 6 + goalkeeper (6 vs. 6) small-sided games (SSGs) is equivalent to those experienced during the most intense 5-minute period of soccer match play. Twenty-six male soccer players from an elite Norwegi...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Compression Stockings Used During Two Soccer Matches Improve Perceived Muscle Soreness and High-Intensity Performance
Gimenes, SV, Marocolo, M, Pavin, LN, Pagoto Spigolon, LM, Neto, OB, Côrrea da Silva, BV, Duffield, R, and Ribeiro da Mota, G. Compression stockings used during two soccer matches improve perceived muscle soreness and high-intensity performance. J Strength Cond Res 35(7): 2010–2017, 2021—Evidence on the use of compression stockings (CS) during soccer matches is limited. Thus, we evaluated the acute effects of CS on match-based physical performance indicators and perceptual responses during 2 consecutive soccer matches with 72-hour recovery. Twenty outfield players were randomly allocated to the CS group (2...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Ecological and Construct Validity of a Repeated Sprint Test in Male Youth Soccer Players
This study aimed to examine the relationship between a repeated sprint ability (RSA) test (5 bouts of 30-m sprints interspersed by 30 seconds of recovery) and match-related physical performance in male youth soccer players. Although 60 outfield players were evaluated, only data from players who participated in the full matches (n = 39) were retained (8 central defenders, 7 external defenders, 8 central midfielders, 8 external midfielders, and 8 forwards). To verify the ecological validity of this RSA protocol, the association between the best (RSAbest) and mean (RSAmean) sprint time in the 5 × 30-m and physical match...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Sex-Related Hip Strength Measures Among Professional Soccer Players
Hedt, CA, Pearson, JM, Lambert, BS, McCulloch, PC, and Harris, JD. Sex-related hip strength measures among professional soccer players. J Strength Cond Res 35(7): 1992–1999, 2021—Lower-extremity musculoskeletal injuries in soccer are common among sexes. However, it remains unknown whether differences between sexes exist with regard to absolute or relative hip strength and how these differences may relate to injury. In the current study, we performed a retrospective cross-sectional analysis of pre-season data from male (♂n = 21) and female (♀n = 19) professional United States soccer organizations. Two years ...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Physiological Responses During Female Judo Combats: Impact of Combat Area Size and Effort to Pause Ratio Variations
This study investigated the effect of area size (4 × 4, 6 × 6, and 8 × 8 m) and effort-pause ratio (free combat, 2:1 and 3:1) on the physiological and perceptive responses during female judo combats. Twelve female judo athletes (mean ± SD: age: 17.1 ± 0.4 years; height: 160 ± 7 cm; body mass: 59.8 ± 11.5 kg; body fat: 25.7 ± 5.5%; and judo experience: 8.4 ± 0.5 years) volunteered to perform nine 4-minute randoris randomly determined. Blood lactate [La] before and after combats, heart rate before combat (HRpre), mean HR (HRmean), peak HR (HRpeak), and rating of per...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Passive Heat Maintenance After an Initial Warm-up Improves High-Intensity Activity During an Interchange Rugby League Movement Simulation Protocol
This study examined using passive heat maintenance (PHM) to maintain core temperature after a warm-up and its effect on simulated first half running performance in rugby players. Thirteen male rugby players completed this randomized crossover study. Tympanic temperature was taken before a warm-up and then after a further 15 minutes of passive recovery either with (PHM) or without (CON) a PHM garment. Subjects then completed 23 minutes of the rugby league movement simulation protocol (RLMSP-i). Differences in tympanic temperature were unclear between CON and PHM before (35.7 ± 1.3 cf. 36.0 ± 1.1° C; effect...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Effects of a Rugby League Match Simulation on Decision-Making in Elite Junior Rugby League
Redman, K, Steel, K, Kelly, V, and Siegler, J. Effects of a rugby league match simulation on decision-making in elite junior rugby league. J Strength Cond Res 35(7): 1972–1980, 2021—The paucity of research on decision-making in Rugby league within the context of a match, and the potential for age and playing experience to influence decision-making ability, warrants further investigation. Therefore, the aim of this study was to determine the effects of a simulated rugby league match on decision-making in elite junior rugby league players. Twenty male junior rugby league players (age 15.9 ± 0.9 years, body...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

The Duration-specific Peak Average Running Speeds of European Super League Academy Rugby League Match Play
This study aimed to quantify the duration-specific peak average running speeds of Academy-level rugby league match play, and compare between playing positions. Global positioning system data were collected from 149 players competing across 9 teams during 21 professional Academy (under-19) matches. Players were split into 6 positions: hookers (n = 40), fullbacks (n = 24), halves (n = 47), outside backs (n = 104), middles (n = 118), and backrow forwards (n = 104). Data were extracted and the 10-Hz raw velocity files exported to determine the peak average running speeds, via moving averages of speed (m·min−1), fo...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Validity of an Interval Taekwondo-Specific Cardiopulmonary Exercise Test
The objective of this study is to propose and validate an interval taekwondo-specific cardiopulmonary exercise test (ITKDtest) and compare it with running cardiopulmonary exercise test (CPET) and a continuous taekwondo-specific cardiopulmonary exercise test (CTKDtest). Fifteen athletes (age 22 ± 4 years; body mass 71.1 ± 10.2 kg; height 178.14 ± 8.3 cm; and body mass index 22.4 ± 2.4 kg·m−2) performed CPET, CTKDtest, and ITKDtest on a counterbalanced order. Oxygen uptake (V̇o2), heart rate (HR), and ventilatory thresholds (VTs 1 and 2) were measured during the 3 tests. ITKDtest sta...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Is What You See What You Get? Perceptions of Personal Trainers' Competence, Knowledge, and Preferred Sex of Personal Trainer Relative to Physique
Boerner, PR, Polasek, KM, True, L, Lind, E, and Hendrick, JL. Is what you see what you get? Perceptions of personal trainers' competence, knowledge, and preferred sex of personal trainer relative to physique. J Strength Cond Res 35(7): 1949–1955, 2021—The role that a personal trainer's (PT) physique plays in how potential clients perceive the PT is an understudied, yet potentially powerful, area of inquiry that has important professional implications. The purpose of this study was to investigate how a PT's physique could influence perceptions of his/her (a) PT competence, (b) level of personal training knowledg...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Resistance Training Practices of Sprint Coaches
This study describes the results of a survey of resistance training practices of sprint coaches. This study investigated why sprint coaches prescribe resistance training to their athletes, what exercises they select, and what factors are involved with their selection. Forty-one of 73 (56%) sprint coaches with mean ± SD coaching experience of 8.4 ± 6.4 years were included in this study. Coaches completed an online questionnaire consisting of 5 sections: (a) informed consent, (b) coach background information, (c) coach education and qualifications, (d) coaches' views on resistance training, and (e) exercise sel...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Association of Functional Movement Screen and Y-Balance Test Scores With Injury in High School Athletes
Lisman, P, Hildebrand, E, Nadelen, M, and Leppert, K. Association of functional movement screen and Y-Balance Test scores with injury in high school athletes. J Strength Cond Res 35(7): 1930–1938, 2021—The purpose of this study was to determine the association between functional movement screen (FMS) and Y-Balance Test (YBT) performance and lower extremity injury in a sample of male high school athletes. A total of 124 high school football (n = 89), lacrosse (n = 25), and baseball (n = 10) players underwent FMS and YBT before the start of their competitive seasons. Time loss lower extremity injury incidence dat...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Chronic Effects of a Static Stretching Program on Hamstring Strength
This study investigated the effects of a 4-week static stretching (SS) program on isokinetic and isometric knee flexor peak torque and angle of peak torque. Thirty healthy men (age, 22.7 ± 2.2 years) were randomized to receive either of the following: (a) a 4-week stretch intervention for the hamstrings (SS intervention group; n = 15) or (b) no intervention (control group; n = 15). The maximum pain-free knee angle, passive stiffness, which was determined by a slope of torque-angle curve, isometric and isokinetic (at 60°·s−1 and 180°·s−1) peak torque, and angle of peak torque for kne...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Effects of Equal Volume But Different Plyometric Jump Training Intensities on Components of Physical Fitness in Physically Active Young Males
Ramirez-Campillo, R, Moran, J, Drury, B, Williams, M, Keogh, JW, Chaabene, H, and Granacher, U. Effects of equal volume but different plyometric jump training intensities on components of physical fitness in physically active young males. J Strength Cond Res 35(7): 1916–1923, 2021—An 8-week single-blind randomized controlled trial was conducted to compare the effects of separate programs of equal volume, but different intensity, plyometric jump training (PJT), on physical fitness in healthy adults. Thirty-eight physically active males (mean age: 21.8 ± 2.5 years) participated. Subjects were randomly assi...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Effects of Resistance Training on Physical Performance in High-Level 800-Meter Athletes: A Comparison Between High-Speed Resistance Training and Circuit Training
This study compared the effects of 2 resistance training programs during 25 weeks on physical performance and hormonal response in high-level 800 m athletes. Thirteen male athletes (800-m personal best: 1:43–1:58 minutes:ss) were divided into 2 groups: high-speed resistance training group (RTG) (n = 6) and circuit training group (CTG) (n = 7). Three tests (T1, T2, and T3) including sprint and 800 m running, strength exercises, and blood hormones samples were performed. Both groups showed improvements in 800 m performance (RTG: likely positive, 80/20/0%; CTG: very likely positive, 98/2/0%); however, RTG showed an addi...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Oxygenation Responses While Wearing the Elevation Training Mask During an Incremental Cycling Test
Romero-Arenas, S, López-Pérez, E, Colomer-Poveda, D, and Márquez, G. Oxygenation responses while wearing the elevation training mask during an incremental cycling test. J Strength Cond Res 35(7): 1897–1904, 2021—The Elevation Training Mask 2.0 (ETM) is a commercial training mask that purportedly simulates altitude training, although their effects have not been conclusively demonstrated. Therefore, the purpose of this study was to evaluate the influence of wearing the ETM on muscle and brain oxygenation responses during a maximal incremental cycling test, as well as the influence of this dev...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Genetic Basis for the Dominance of Israeli Long-Distance Runners of Ethiopian Origin
Ben-Zaken, S, Meckel, Y, Nemet, D, Kassem, E, and Eliakim, A. Genetic basis for the dominance of Israeli long-distance runners of Ethiopian origin. J Strength Cond Res 35(7): 1885–1896, 2021—Israeli long-distance runners of Ethiopian origin have a major influence on the track and field long-distance record table. The aim of this study was to determine whether genetic characteristics contribute to this long-distance dominance. We assessed polymorphisms in genes related to endurance (PPARD T/C), endurance trainability (ACSL A/G), speed (ACTN3 R/X), strength (AGT T/C), and the recovery from training (MTC1 A/T and ...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Effects of a Soccer Tournament on the Psychohormonal States of Collegiate Female Players
This study evaluates the effects of a week-long tournament on the psychohormonal states of collegiate female soccer players. Eight players' cortisol (saliva sample), mood states (Incredibly Short Profile of Mood States [ISP]), and state-anxiety (state subscale of the State-Trait Anxiety Inventory) were assessed 1 hour before and 15 minutes after every game. Cortisol increased significantly after most matches, with intramatch differences observed (p 1.2). Match intensity influenced cortisol secretion, with greater secretion as intensity increased. The ISP demonstrated intramatch differences for the subscales' fatigue, depre...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Predictors of Fat Oxidation and Caloric Expenditure With and Without Weighted Vest Running
This study evaluated the effect of weighted vest running (WVR) on fatty acid oxidation (FAox) and caloric expenditure at predesignated steady-state exercise intensities. Seventeen recreationally trained runners (9 men and 8 women) performed 4 separate graded exercise tests (GXTs) separated by at least 24 hours. The first GXT was a V̇o2max test to establish running velocities (percentage of max) at the prespecified exercise intensities (60, 65, 70, 75, and 80% V̇o2max). The following randomized WVR trials included a control (no vest), 5% body mass (BM) vest, and 10% BM vest using 3-minute incrementally increasing steady-s...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Acute Kinematic Effects of Sprinting With Motorized Assistance
Clark, K, Cahill, M, Korfist, C, and Whitacre, T. Acute kinematic effects of sprinting with motorized assistance. J Strength Cond Res 35(7): 1856–1864, 2021—Although assisted sprinting has become popular for training maximum velocity, the acute effects are not fully understood. To examine this modality, 14 developmental male sprinters (age: 18.0 ± 2.5 years, 100-m personal best: 10.80 ± 0.31 seconds) performed maximal trials, both unassisted and assisted with a motorized towing device using a load of 7 kg (9.9 ± 0.9% body mass). Significant increases in maximum velocity (+9.4%, p ≤ 0.001...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research

Principal Component Analysis of the Associations Between Kinetic Variables in Cutting and Jumping, and Cutting Performance Outcome
Welch, N, Richter, C, Moran, K, and Franklyn-Miller, A. Principal component analysis of the associations between kinetic variables in cutting and jumping, and cutting performance outcome. J Strength Cond Res 35(7): 1848–1855, 2021—The primary aim of this study was to determine which features within the ground reaction force (GRF) trace during cutting are related to performance outcome in different angled cuts. The secondary aim was to understand the relationship between GRF features in a series of maximum strength, explosive strength, and reactive strength tests, and cutting performance outcome. Twenty-five mal...
Source: Journal of Strength and Conditioning Research - July 1, 2021 Category: Sports Medicine Tags: Original Research Source Type: research