Relationships Between Countermovement Jump Ground Reaction Forces and Jump Height, Reactive Strength Index, and Jump Time
In conclusion, jump height correlated with variables derived from the concentric phase only (work, power, and displacement), whereas Fz variables from the unloading, eccentric, amortization, and concentric phases correlated highly with RSI and jump time. These observations demonstrate the importance of countermovement Fz characteristics for time-sensitive CMJ performance measures. Researchers and practitioners should include RSI and jump time with jump height to improve their assessment of jump performance. (Source: Journal of Strength and Conditioning Research)
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Acute Effects of Ammonia Inhalants on Strength and Power Performance in Trained Men
Bartolomei, S, Nigro, F, Luca, G, Gabriele, S, Ciacci, S, Hoffman, JR, and Merni, F. Acute effects of ammonia inhalants on strength and power performance in trained men. J Strength Cond Res 32(1): 244–247, 2018—The aim of the present study was to investigate the influence of ammonia inhalants on lower body power and maximal isometric strength in trained men. Twenty experienced resistance trained men (age = 26.7 ± 3.7 years; body weight = 80.59 ± 9.0 kg; body height = 179.5 ± 5.7 cm) were tested for counter movement jump power (CMJP), maximal force, and peak rate of force development (pRFD20...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Effects of Jaw Clenching and Jaw Alignment Mouthpiece Use on Force Production During Vertical Jump and Isometric Clean Pull
This study examined the effects of jaw clenching, a self-adapted, jaw-repositioning mouthpiece on force production during maximum countermovement vertical jump and maximum isometric midthigh clean pull assessments in an attempt to determine any ergogenic effect attributable to clenching, jaw-repositioning mouthpiece use, or the combination of both. Thirty-six male subjects performed vertical jump and isometric clean pull assessments from a force platform under various mouthpiece and clench conditions. A 3 × 2 (mouthpiece × clench) repeated-measures analysis of variance was conducted to analyze each of the follo...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Effects of Two Different Self-Adapted Occlusal Splints on Electromyographic and Force Parameters During Elbow Flexors Isometric Contraction
Limonta, E, Arienti, C, Rampichini, S, Venturelli, M, Cè, E, Veicsteinas, A, and Esposito, F. Effects of two different self-adapted occlusal splints on electromyographic and force parameters during elbow flexors isometric contraction. J Strength Cond Res 32(1): 230–236, 2018—The study was aimed at determining the acute effects of 2 types of occlusal splints on maximum isometric strength and fatigue of the elbow flexors muscles. The hypothesis was that splint-induced masticatory muscle repositioning might improve primary muscles recruitment by stretching masticatory muscles especially with the thicker spl...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

High-Intensity Interval Exercises' Acute Impact on Heart Rate Variability: Comparison Between Whole-Body and Cycle Ergometer Protocols
Schaun, GZ and Del Vecchio, FB. High-intensity interval exercises' acute impact on heart rate variability: comparison between whole-body and cycle ergometer protocols. J Strength Cond Res 32(1): 223–229, 2018—Study aimed to compare the effects of 2 high-intensity interval training (HIIT) protocols on heart rate variability. Twelve young adult males (23.3 ± 3.9 years, 177.8 ± 7.4 cm, 76.9 ± 12.9 kg) volunteered to participate. In a randomized cross-over design, subjects performed 2 HIIT protocols, 1 on a cycle ergometer (Tabata protocol [TBT]; eight 20-second bouts at 170% Pmax interspersed ...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

The Effects of Nordic Walking and Slope of the Ground on Lower Limb Muscle Activity
Psurny, M, Svoboda, Z, Janura, M, Kubonova, E, Bizovska, L, Martinez Lemos, RI, and Abrantes, J. The effects of Nordic walking and slope of the ground on lower limb muscle activity. J Strength Cond Res 32(1): 217–222, 2018—Nordic walking (NW) has proven to be a simple and safe mode of exercise that can be used in various types of sport, recreation, and rehabilitation activities. The aim of this study was to assess the effect of Nordic walking and slope of the ground on lower limb muscle activity. The experimental group consisted of 22 healthy men (aged 22.8 ± 1.4 years). The subjects walked on a treadmil...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Halftime Rewarm-up With Intermittent Exercise Improves the Subsequent Exercise Performance of Soccer Referees
In conclusion, this study showed that halftime RW with intermittent exercise improves the subsequent exercise performance. (Source: Journal of Strength and Conditioning Research)
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Effects of Fat Grip Training on Muscular Strength and Driving Performance in Division I Male Golfers
Cummings, PM, Waldman, HS, Krings, BM, Smith, JW, and McAllister, MJ. Effects of fat grip training on muscular strength and driving performance in division I male golfers. J Strength Cond Res 32(1): 205–210, 2018—Fat grip (FG) training is implemented into strength and conditioning programs with the overall goal of increasing grip strength. Previous research assessing the effect of training with increased grip diameters compared with standard Olympic bar diameters has mainly been in acute settings. Therefore, the purpose of this study was to examine to effects FG training compared with normal diameter grip (CON)...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

System for Evaluating Powerlifting and Other Multievent Performances
Bishop, PA, Williams, TD, Heldman, AN, and Vanderburgh, PM. System for evaluating powerlifting and other multievent performances. J Strength Cond Res 32(1): 201–204, 2018—Currently, the sport of powerlifting discriminates against bench press scores and uses an empirical equation which is very difficult to update to determine the best lifter within sex. The purpose of this study was to provide a simple and statistically sound method for evaluating powerlifting performance which could also be used with other multievent sports. Data were collected from a large public database on the top 50 (men) or the top 30 (wom...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Metabolic and Mechanical Effects of Laddermill Graded Exercise Testing
Allerton, TD, Earnest, CP, and Johannsen, NM. Metabolic and mechanical effects of laddermill graded exercise testing. J Strength Cond Res 32(1): 195–200, 2018—The purpose of this study was to compare the metabolic responses and mechanical impact forces during a maximal graded exercise test (GXT) on a laddermill (LM) vs. a standard treadmill (TM). Twenty college-aged men (n = 10) and women completed a GXT on the TM and LM in random order. During the GXT, expired gases (V[Combining Dot Above]O2 and V[Combining Dot Above]CO2), heart rate, accelerometer data, blood lactate (BLa), and rating of perceived exertion (R...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Longer Sleep Durations Are Positively Associated With Finishing Place During a National Multiday Netball Competition
This study objectively evaluated sleep characteristics of athletes during a national netball tournament. Using wrist actigraphy monitors and sleep diaries, 42 netballers from 4 state teams were monitored for the duration of a tournament (6 days) and 12 days before in home environments. Significant differences were found between teams based on final competition standings, suggesting enhanced sleep characteristics in athlete's whose team finished higher in the tournament standings. The top 2 placed teams when compared with the lower 2 placed teams slept longer (8:02 ± 36:43; 7:01 ± 27:33), had greater time in b...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Short-Term Hypoxic Exposure and Training Improve Maximal Anaerobic Running Test Performance
Oriishi, M, Matsubayashi, T, Kawahara, T, and Suzuki, Y. Short-term hypoxic exposure and training improve maximal anaerobic running test performance. J Strength Cond Res 32(1): 181–188, 2018—The purpose of this study was to examine the effectiveness of short-term hypoxic exposure and training in the performance of competitive 400- or 800-m runners. Fifteen female competitive 400- and 800-m runners volunteered to participate and were assigned to either the hypoxic (n = 7) or normoxic (n = 8) group. The subjects completed 6 days of training. The hypoxic group trained and slept in normobaric hypoxia, with oxygen c...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Effects of Hyperventilation on Repeated Pedaling Sprint Performance: Short vs. Long Intervention Duration
Sakamoto, A, Naito, H, and Chow, C-M. Effects of hyperventilation on repeated pedaling sprint performance: short vs. long intervention duration. J Strength Cond Res 32(1): 170–180, 2018—Previously, hyperventilation (HV)-induced respiratory alkalosis, implemented during the last 30 seconds of each 60-second recovery that separated repeated pedaling sprints, has been shown to attenuate performance decrement. The present study investigated whether the ergogenic effects of HV would hold if the HV duration was shortened or extended. Seventeen power-trained athletes performed 10 seconds × 10 sets of standing pe...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Effect of Resistance Training to Muscle Failure vs. Volitional Interruption at High- and Low-Intensities on Muscle Mass and Strength
Nóbrega, SR, Ugrinowitsch, C, Pintanel, L, Barcelos, C, and Libardi, CA. Effect of resistance training to muscle failure vs. volitional interruption at high- and low-intensities on muscle mass and strength. J Strength Cond Res 32(1): 162–169, 2018—The purpose of this study was to investigate the effects of resistance training (RT) at high- and low-intensities performed to muscle failure or volitional interruption on muscle strength, cross-sectional area (CSA), pennation angle (PA), and muscle activation. Thirty-two untrained men participated in the study. Each leg was allocated in 1 of 4 unilateral RT pr...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

The 1 Repetition Maximum Mechanics of a High-Handle Hexagonal Bar Deadlift Compared With a Conventional Deadlift as Measured by a Linear Position Transducer
This study compared the mechanics between a 1 repetition maximum (1RM) CD and HHBD. Thirty-one strength-trained subjects (21 men, 10 women) completed a 1RM CD and HHBD. A linear position transducer measured lift distance, duration, and work; and peak and mean power, velocity, and force. The presence of a sticking region (SR) was determined for each lift. A repeated-measures analysis of variance (ANOVA) calculated differences between 1RM CD and HHBD mechanics. A one-way ANOVA compared the mechanics of each lift between subjects who exhibited an SR or not, and the SR between the CD and HHBD. Significance was set at p (Source...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Maturation-Related Differences in Adaptations to Resistance Training in Young Male Swimmers
This study examined the effects of resistance training on muscular strength and jump performances in young male swimmers. It was hypothesized that adaptations would be of a lower magnitude in less mature (prepeak height velocity [PHV]) than in more mature (post-PHV) subjects. Fourteen pre-PHV (−1.8 ± 1.0 years) and 8 post-PHV (1.6 ± 0.5 years) swimmers undertook a 30 minutes, twice-weekly resistance training program for 8 weeks. They were compared with matched control groups (pre-PHV: −2.0 ± 1.1, n = 15; post-PHV: 1.2 ± 1.0, n = 7). The effects on lower-body isometric strength (LBS),...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Neuromuscular and Cardiovascular Adaptations in Response to High-Intensity Interval Power Training
Romero-Arenas, S, Ruiz, R, Vera-Ibáñez, A, Colomer-Poveda, D, Guadalupe-Grau, A, and Márquez, G. Neuromuscular and cardiovascular adaptations in response to high-intensity interval power training. J Strength Cond Res 32(1): 130–138, 2018—The aim of this study was to determine the efficacy of a high-intensity power training (HIPT) program, and to compare the effects of HIPT to traditional power training (TPT) on the aerobic and power performance. For this purpose, 29 healthy men (23.1 ± 2.7 years) were recruited and randomly distributed into 3 different groups. One group performed TPT...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Validity of BMI-Based Body Fat Equations in Men and Women: A 4-Compartment Model Comparison
Nickerson, BS, Esco, MR, Bishop, PA, Fedewa, MV, Snarr, RL, Kliszczewicz, BM, and Park, K-S. Validity of BMI-based body fat equations in men and women: a 4-compartment model comparison. J Strength Cond Res 32(1): 121–129, 2018—The purpose of this study was to compare body mass index (BMI)–based body fat percentage (BF%) equations and skinfolds with a 4-compartment (4C) model in men and women. One hundred thirty adults (63 women and 67 men) volunteered to participate (age = 23 ± 5 years). BMI was calculated as weight (kg) divided by height squared (m2). BF% was predicted with the BMI-based equations...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

The Effects of Muscle Strength Responsiveness to Periodized Resistance Training on Resistin, Leptin, and Cytokine in Elderly Postmenopausal Women
Prestes, J, Nascimento, DdC, Neto, IVS, Tibana, RA, Shiguemoto, GE, Perez, SEA, Botero, JP, Schoenfeld, BJ, and Pereira, GB. The effects of muscle strength responsiveness to periodized resistance training on resistin, leptin, and cytokine in elderly postmenopausal women. J Strength Cond Res 32(1): 113–120, 2018—The aim of this study was to evaluate muscle strength responsiveness and to determine whether interleukin 4 (IL-4), leptin, and resistin would be affected by the individual pattern of response to a resistance training (RT) periodization program. Twenty-six elderly postmenopausal women participated in the...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Fitness Profiles of Elite Adolescent Irish Rugby Union Players
Wood, DJ, Coughlan, GF, and Delahunt, E. Fitness profiles of elite adolescent Irish rugby union players. J Strength Cond Res 32(1): 105–112, 2018—Rugby unions throughout the world are implementing player development models to prepare young players to meet the demands of professional rugby union. An example of this is the Irish Rugby Football Union Long Term Player Development model. The purpose of this study was to provide normative data relating to the physical fitness of elite adolescent Irish rugby union players and determine the differences in the physical capacities between players in the forward and back ...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Differential Effects of Continuous Versus Discontinuous Aerobic Training on Blood Pressure and Hemodynamics
Landram, MJ, Utter, AC, Baldari, C, Guidetti, L, McAnulty, SR, and Collier, SR. Differential effects of continuous versus discontinuous aerobic training on blood pressure and hemodynamics. J Strength Cond Res 32(1): 97–104, 2018—The purpose of this study was to compare the hemodynamic, arterial stiffness, and blood flow changes after 4 weeks of either continuous or discontinuous aerobic exercise in adults. Forty-seven subjects between the ages of 18 and 57 were recruited for 1 month of either continuous aerobic treadmill work for 30 minutes at 70% max heart rate or 3 bouts of 10 minutes of exercise at 70% of ma...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Reliability and Sensitivity of the Power Push-up Test for Upper-Body Strength and Power in 6–15-Year-Old Male Athletes
Gillen, ZM, Miramonti, AA, McKay, BD, Jenkins, NDM, Leutzinger, TJ, and Cramer, JT. Reliability and sensitivity of the power push-up test for upper-body strength and power in 6–15-year-old male athletes. J Strength Cond Res 32(1): 83–96, 2018—The power push-up (PPU) test is an explosive upper-body test performed on a force plate and is currently being used in high school football combines throughout the United States. The purpose of this study was to quantify the reliability of the PPU test based on age and starting position (knees vs. toes) in young athletes. Sixty-eight boys (mean ± SD; age = 10....
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Adding Resistance Training to the Standard of Care for Inpatient Substance Abuse Treatment in Men With Human Immunodeficiency Virus Improves Skeletal Muscle Health Without Altering Cytokine Concentrations
Vingren, JL, Curtis, JH, Levitt, DE, Duplanty, AA, Lee, EC, McFarlin, BK, and Hill, DW. Adding resistance training to the standard of care for inpatient substance abuse treatment in men with human immunodeficiency virus improves skeletal muscle health without altering cytokine concentrations. J Strength Cond Res 32(1): 76–82, 2018—Substance abuse and human immunodeficiency virus (HIV) infection can independently lead to myopathy and related inflammatory alterations; importantly, these effects seem to be additive. Resistance training (RT) can improve muscle health in people living with HIV (PLWH), but the effica...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Long-Term Changes in Jump Performance and Maximum Strength in a Cohort of National Collegiate Athletic Association Division I Women's Volleyball Athletes
Kavanaugh, AA, Mizuguchi, S, Sands, WA, Ramsey, MW, and Stone, MH. Long-term changes in jump performance and maximum strength in a cohort of NCAA division I women's volleyball Athletes. J Strength Cond Res 32(1): 66–75, 2018—The purpose of this investigation was to quantify the magnitude of change in maximal strength and jumping abilities over approximately 1, 2, and 3 years of supervised sport and resistance training in National Collegiate Athletic Association (NCAA) division I women's volleyball athletes. This was an exploratory study on a cohort of women's volleyball athletes (n = 29) split into 3 groups bas...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Asymmetries of Maximum Trunk, Hand, and Leg Strength in Comparison to Volleyball and Fitness Athletes
Mattes, K, Wollesen, B, and Manzer, S. Asymmetries of maximum trunk, hand, and leg strength in comparison to volleyball and fitness athletes. J Strength Cond Res 32(1): 57–65, 2018—Playing volleyball and corresponding training loads lead to specific strains and might result in asymmetric muscle pattern. The study aimed to identify volleyball-specific maximum bilateral strength asymmetries in comparison to fitness athletes. The cross-sectional study design compared an age-matched male volleyball group (n = 23; 27.9 ± 5 years) with a fitness group (n = 30; 26.3 ± 3 years). The participants performed...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Effect of Body Position on Force Production During the Isometric Midthigh Pull
Beckham, GK, Sato, K, Santana, HAP, Mizuguchi, S, Haff, GG, and Stone, MH. Effect of body position on force production during the isometric midthigh pull. J Strength Cond Res 32(1): 48–56, 2018—Various body positions have been used in the scientific literature when performing the isometric midthigh pull resulting in divergent results. We evaluated force production in the isometric midthigh pull in bent (125° knee and 125° hip angles) and upright (125° knee, 145° hip angle) positions in subjects with (>6 months) and without ( (Source: Journal of Strength and Conditioning Research)
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Effects of Lower-Limb Strength Training on Agility, Repeated Sprinting With Changes of Direction, Leg Peak Power, and Neuromuscular Adaptations of Soccer Players
We examined the effects on explosive muscular performance of incorporating 8 weeks strength training into the preparation of junior male soccer players, allocating subjects between an experimental group (E, n = 19) and a matched control group (C, n = 12). Controls maintained their regular training program, but the experimental group replaced a part of this schedule by strength training. Performance was assessed using running times (5, 10, 20, 30 and 40 m), a sprint test with 180° turns (S180°), a 9-3-6-3-9 m sprint with backward and forward running (SBF), a 4 × 5 m sprint test with turns, repeated shuttle spr...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Hypertrophy and Explosive-Reactive Functioning in Sedentary Men After 10 Weeks of Whole-Body Vibration
The objective of this study was to determine the impact of vertical (Power-plate; POW) and side-alternating (Galileo; GAL) whole-body vibration exercise on muscle mass and lower-limb neuromuscular function. Forty-three sedentary male subjects (18–30 year) randomized into 3 groups underwent 2 upper-body exercise sessions per week for 10 weeks. Two groups of subjects underwent additional squat exercises on the GAL (N = 15) or POW (N = 14) devices. The third group was control. On magnetic resonance imaging, volume of the thigh muscles was measured. Countermovement jump, multiple one-leg hopping, drop jump, landing test,...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

β-Hydroxy β-Methylbutyrate (HMB) Supplementation Effects on Body Mass and Performance in Elite Male Rugby Union Players
McIntosh, ND, Love, TD, Haszard, J, Osborne, H, and Black, KE. β-hydroxy β-methylbutyrate (HMB) supplementation effects on body mass and performance in elite male rugby union players. J Strength Cond Res 32(1): 19–26, 2018—Preseason is characterized by high training volumes with short recovery periods β-hydroxy β-methylbutyrate (HMB) has been postulated to assist with recovery. β-hydroxy β-methylbutyrate has been shown to improve strength and body composition among untrained groups; the benefits of HMB among trained populations are unclear because of the methodologies employed. Thi...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Effect of Lower-Body Resistance Training on Upper-Body Strength Adaptation in Trained Men
Bartolomei, S, Hoffman, JR, Stout, JR, and Merni, F. Effect of lower-body resistance training on upper-body strength adaptation in trained men. J Strength Cond Res 32(1): 13–18, 2018—The aim of this study was to examine the effect of 2 different lower-body strength training schemes on upper-body adaptations to resistance training. Twenty resistance-trained men (4.25 ± 1.6 years of experience) were randomly assigned to either a high intensity (HI; n = 9; age = 24.9 ± 2.9 years; body mass = 88.7 ± 17.2 kg; height = 177.0 ± 5.6 cm) or a mixed high volume and HI resistance training progr...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

A Hydrothermally Processed Maize Starch and Its Effects on Blood Glucose Levels During High-Intensity Interval Exercise
Hetrick, MM, Naquin, MR, Gillan, WW, Williams, BM, and Kraemer, RR. A hydrothermally processed maize starch and its effects on blood glucose levels during high-intensity interval exercise. J Strength Cond Res 32(1): 3–12, 2018—A hydrothermally processed maize starch (HPMS) has been shown to blunt initial blood glucose and insulin response during endurance activity at 70% maximal oxygen uptake (V[Combining Dot Above]O2max). High-intensity interval training (HIIT) is a form of exercise that has many health benefits although it is only performed for short periods of time with interspersed rest periods. The purpose...
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Original Research Source Type: research

Chasing the Mission for 30 Years: Bridging the Gap
No abstract available (Source: Journal of Strength and Conditioning Research)
Source: Journal of Strength and Conditioning Research - January 1, 2018 Category: Sports Medicine Tags: Editorial Source Type: research

Authors' Response
No abstract available (Source: Journal of Strength and Conditioning Research)
Source: Journal of Strength and Conditioning Research - December 21, 2017 Category: Sports Medicine Tags: Manuscript Clarification Source Type: research

Inappropriate Methods and Flawed Conclusion in: Can Resistance Training Enhance the Rapid Force Development in Unloaded Dynamic Isoinertial Multijoint Movements? A Systematic Review
No abstract available (Source: Journal of Strength and Conditioning Research)
Source: Journal of Strength and Conditioning Research - December 21, 2017 Category: Sports Medicine Tags: Manuscript Clarification Source Type: research

Effects of Two Different Training Periodization Models on Physical and Physiological Aspects of Elite Female Team Handball Players
Abstract: Manchado, C, Cortell-Tormo, JM, and Tortosa-Martínez, J. Effects of two different training periodization models on physical and physiological aspects of elite female team handball players. J Strength Cond Res 32(1): 280–287, 2018—The aim of this study was to compare training-induced changes in selected physiological and physical team handball performance factors after 2 training periodization models: traditional periodization (TP) vs. block periodization (BP). Eleven female team handball players who played over 2 consecutive seasons for a Spanish first league team were assessed twice per season...
Source: Journal of Strength and Conditioning Research - December 21, 2017 Category: Sports Medicine Tags: Original Research Source Type: research

Resistance Training Is Associated With Higher Lumbar Spine and Hip Bone Mineral Density in Competitive Male Cyclists
Abstract: Mathis, SL, and Caputo, JL. Resistance training is associated with higher lumbar spine and hip bone mineral density in competitive male cyclists. J Strength Cond Res 32(1): 274–279, 2018—In contrast to other athletic activities, competitive cycling is associated with low areal bone mineral density (BMD). This investigation evaluated training and dietary factors associated with BMD in a sample of competitive male cyclists. Lumbar spine, total hip, femoral neck, and femoral trochanter BMD were measured with dual X-ray absorptiometry in 40 cyclists at the start of a cycling season. Participants reported ...
Source: Journal of Strength and Conditioning Research - December 21, 2017 Category: Sports Medicine Tags: Original Research Source Type: research

Factors Influencing Spike Jump Height in Female College Volleyball Players
Abstract: Ikeda, Y, Sasaki, Y, and Hamano, R. Factors influencing spike jump height in female college volleyball players. J Strength Cond Res 32(1): 267–273, 2018—The purpose of this study was to examine factors influencing spike jump (SPJ) performance by female competitive volleyball players through comparisons of the kinematic data of SPJ with those of the standing long jump (SLJ) and vertical jump (VJ). Seventeen female competitive volleyball players were asked to perform SPJ, SLJ, and VJ. Motion data of SPJ including the approach phase were recorded. Regarding SLJ and VJ, jumping motion and ground reaction ...
Source: Journal of Strength and Conditioning Research - December 21, 2017 Category: Sports Medicine Tags: Original Research Source Type: research

The Relationship Between Trunk Rotation, Upper Quarter Dynamic Stability, and Pitch Velocity
Abstract: Bullock, GS, Schmitt, AC, Chasse, PM, Little, BA, Diehl, LH, and Butler, RJ. The relationship between trunk rotation, upper quarter dynamic stability, and pitch velocity. J Strength Cond Res 32(1): 261–266, 2018—Understanding the relationship between upper quarter mobility, dynamic stability, and pitching velocity may be beneficial in elucidating underlying factors that affect pitching performance. The purpose of this study was to investigate upper trunk rotation mobility and upper quarter dynamic stability and their correlation to pitch velocity in NCAA Division I collegiate pitchers. We hypothesized...
Source: Journal of Strength and Conditioning Research - December 21, 2017 Category: Sports Medicine Tags: Original Research Source Type: research

Relationships Between Concentric and Eccentric Strength and Countermovement Jump Performance in Resistance Trained Men
Abstract: Bridgeman, LA, McGuigan, MR, Gill, ND, and Dulson, DK. Relationships between concentric and eccentric strength and countermovement jump performance in resistance trained men. J Strength Cond Res 32(1): 255–260, 2018—The purpose of this study was to investigate the relationships between concentric and eccentric peak force (PF) and countermovement jump (CMJ) performance in resistance trained men. Subjects were 12 men (mean ± SD; age: 25.4 ± 3.5 years; height: 177.2 ± 4.5 cm; mass: 84.0 ± 10.1 kg). The men were tested for concentric and eccentric PF using the Exerbotics squat ...
Source: Journal of Strength and Conditioning Research - December 21, 2017 Category: Sports Medicine Tags: Short Research Report Source Type: research

Relationships Between Countermovement Jump Ground Reaction Forces and Jump Height, Reactive Strength Index, and Jump Time
In conclusion, jump height correlated with variables derived from the concentric phase only (work, power, and displacement), whereas Fz variables from the unloading, eccentric, amortization, and concentric phases correlated highly with RSI and jump time. These observations demonstrate the importance of countermovement Fz characteristics for time-sensitive CMJ performance measures. Researchers and practitioners should include RSI and jump time with jump height to improve their assessment of jump performance. (Source: Journal of Strength and Conditioning Research)
Source: Journal of Strength and Conditioning Research - December 21, 2017 Category: Sports Medicine Tags: Original Research Source Type: research

Acute Effects of Ammonia Inhalants on Strength and Power Performance in Trained Men
Abstract: Bartolomei, S, Nigro, F, Luca, G, Gabriele, S, Ciacci, S, Hoffman, JR, and Merni, F. Acute effects of ammonia inhalants on strength and power performance in trained men. J Strength Cond Res 32(1): 244–247, 2018—The aim of the present study was to investigate the influence of ammonia inhalants on lower body power and maximal isometric strength in trained men. Twenty experienced resistance trained men (age = 26.7 ± 3.7 years; body weight = 80.59 ± 9.0 kg; body height = 179.5 ± 5.7 cm) were tested for counter movement jump power (CMJP), maximal force, and peak rate of force developme...
Source: Journal of Strength and Conditioning Research - December 21, 2017 Category: Sports Medicine Tags: Original Research Source Type: research

Effects of Jaw Clenching and Jaw Alignment Mouthpiece Use on Force Production During Vertical Jump and Isometric Clean Pull
This study examined the effects of jaw clenching, a self-adapted, jaw-repositioning mouthpiece on force production during maximum countermovement vertical jump and maximum isometric midthigh clean pull assessments in an attempt to determine any ergogenic effect attributable to clenching, jaw-repositioning mouthpiece use, or the combination of both. Thirty-six male subjects performed vertical jump and isometric clean pull assessments from a force platform under various mouthpiece and clench conditions. A 3 × 2 (mouthpiece × clench) repeated-measures analysis of variance was conducted to analyze each of the follo...
Source: Journal of Strength and Conditioning Research - December 21, 2017 Category: Sports Medicine Tags: Original Research Source Type: research

Effects of Two Different Self-Adapted Occlusal Splints on Electromyographic and Force Parameters During Elbow Flexors Isometric Contraction
Abstract: Limonta, E, Arienti, C, Rampichini, S, Venturelli, M, Cè, E, Veicsteinas, A, and Esposito, F. Effects of two different self-adapted occlusal splints on electromyographic and force parameters during elbow flexors isometric contraction. J Strength Cond Res 32(1): 230–236, 2018—The study was aimed at determining the acute effects of 2 types of occlusal splints on maximum isometric strength and fatigue of the elbow flexors muscles. The hypothesis was that splint-induced masticatory muscle repositioning might improve primary muscles recruitment by stretching masticatory muscles especially with the t...
Source: Journal of Strength and Conditioning Research - December 21, 2017 Category: Sports Medicine Tags: Original Research Source Type: research

High-Intensity Interval Exercises' Acute Impact on Heart Rate Variability: Comparison Between Whole-Body and Cycle Ergometer Protocols
Abstract: Schaun, GZ and Del Vecchio, FB. High-intensity interval exercises' acute impact on heart rate variability: comparison between whole-body and cycle ergometer protocols. J Strength Cond Res 32(1): 223–229, 2018—Study aimed to compare the effects of 2 high-intensity interval training (HIIT) protocols on heart rate variability. Twelve young adult males (23.3 ± 3.9 years, 177.8 ± 7.4 cm, 76.9 ± 12.9 kg) volunteered to participate. In a randomized cross-over design, subjects performed 2 HIIT protocols, 1 on a cycle ergometer (Tabata protocol [TBT]; eight 20-second bouts at 170% Pmax int...
Source: Journal of Strength and Conditioning Research - December 21, 2017 Category: Sports Medicine Tags: Original Research Source Type: research

The Effects of Nordic Walking and Slope of the Ground on Lower Limb Muscle Activity
Abstract: Psurny, M, Svoboda, Z, Janura, M, Kubonova, E, Bizovska, L, Martinez Lemos, RI, and Abrantes, J. The effects of Nordic walking and slope of the ground on lower limb muscle activity. J Strength Cond Res 32(1): 217–222, 2018—Nordic walking (NW) has proven to be a simple and safe mode of exercise that can be used in various types of sport, recreation, and rehabilitation activities. The aim of this study was to assess the effect of Nordic walking and slope of the ground on lower limb muscle activity. The experimental group consisted of 22 healthy men (aged 22.8 ± 1.4 years). The subjects walked on ...
Source: Journal of Strength and Conditioning Research - December 21, 2017 Category: Sports Medicine Tags: Original Research Source Type: research

Halftime Rewarm-up With Intermittent Exercise Improves the Subsequent Exercise Performance of Soccer Referees
In conclusion, this study showed that halftime RW with intermittent exercise improves the subsequent exercise performance. (Source: Journal of Strength and Conditioning Research)
Source: Journal of Strength and Conditioning Research - December 21, 2017 Category: Sports Medicine Tags: Original Research Source Type: research

Effects of Fat Grip Training on Muscular Strength and Driving Performance in Division I Male Golfers
Abstract: Cummings, PM, Waldman, HS, Krings, BM, Smith, JW, and McAllister, MJ. Effects of fat grip training on muscular strength and driving performance in division I male golfers. J Strength Cond Res 32(1): 205–210, 2018—Fat grip (FG) training is implemented into strength and conditioning programs with the overall goal of increasing grip strength. Previous research assessing the effect of training with increased grip diameters compared with standard Olympic bar diameters has mainly been in acute settings. Therefore, the purpose of this study was to examine to effects FG training compared with normal diameter ...
Source: Journal of Strength and Conditioning Research - December 21, 2017 Category: Sports Medicine Tags: Original Research Source Type: research

System for Evaluating Powerlifting and Other Multievent Performances
Abstract: Bishop, PA, Williams, TD, Heldman, AN, and Vanderburgh, PM. System for evaluating powerlifting and other multievent performances. J Strength Cond Res 32(1): 201–204, 2018—Currently, the sport of powerlifting discriminates against bench press scores and uses an empirical equation which is very difficult to update to determine the best lifter within sex. The purpose of this study was to provide a simple and statistically sound method for evaluating powerlifting performance which could also be used with other multievent sports. Data were collected from a large public database on the top 50 (men) or the t...
Source: Journal of Strength and Conditioning Research - December 21, 2017 Category: Sports Medicine Tags: Original Research Source Type: research

Metabolic and Mechanical Effects of Laddermill Graded Exercise Testing
Abstract: Allerton, TD, Earnest, CP, and Johannsen, NM. Metabolic and mechanical effects of laddermill graded exercise testing. J Strength Cond Res 32(1): 195–200, 2018—The purpose of this study was to compare the metabolic responses and mechanical impact forces during a maximal graded exercise test (GXT) on a laddermill (LM) vs. a standard treadmill (TM). Twenty college-aged men (n = 10) and women completed a GXT on the TM and LM in random order. During the GXT, expired gases (V[Combining Dot Above]O2 and V[Combining Dot Above]CO2), heart rate, accelerometer data, blood lactate (BLa), and rating of perceived e...
Source: Journal of Strength and Conditioning Research - December 21, 2017 Category: Sports Medicine Tags: Original Research Source Type: research

Longer Sleep Durations Are Positively Associated With Finishing Place During a National Multiday Netball Competition
This study objectively evaluated sleep characteristics of athletes during a national netball tournament. Using wrist actigraphy monitors and sleep diaries, 42 netballers from 4 state teams were monitored for the duration of a tournament (6 days) and 12 days before in home environments. Significant differences were found between teams based on final competition standings, suggesting enhanced sleep characteristics in athlete's whose team finished higher in the tournament standings. The top 2 placed teams when compared with the lower 2 placed teams slept longer (8:02 ± 36:43; 7:01 ± 27:33), had greater time in b...
Source: Journal of Strength and Conditioning Research - December 21, 2017 Category: Sports Medicine Tags: Original Research Source Type: research