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This systematic review and meta-analysis compared muscle damage markers and physical performance measures between 2 bouts of multiarticular exercises and determined whether intensity and volume of muscle-damaging exercises affected the outcomes. The eligibility criteria consisted of (a) healthy male and female adults; (b) multiarticular exercises to cause muscle damage across 2 bouts; (c) outcome measures were compared at 24-48 hours after the first and second bouts of muscle-damaging exercise; (d) at least one of the following outcome measures: creatine kinase (CK), delayed onset of muscle soreness (DOMS), muscle strength, and running economy. Study appraisal was conducted using the Kmet tool, whereas forest plots were derived to calculate standardized mean differences (SMDs) and statistical significance and alpha set a 0.05. After screening, 20 studies were included. The levels of DOMSand CK were significantly greater during the first bout when compared with the second bout at T24 and T48 (p<0.001;SMD = 0.51-1.23). Muscular strength and vertical jump performance were significantly lower during the first bout compared with the second bout at T24 and T48 (p ≤ 0.05; SMD = -0.27 to -0.40), whereas oxygen consumption and rating of perceived exertion were significantly greater during the first bout at T24 and T48 (p<0.05; SMD=0.28-0.65) during running economy protocols. The meta-analyses were unaffected by changes in intensity and volume of muscle-damaging exercises between bouts. Multiarticular exercises exhibited a repeated bout effect, suggesting that a single bout of commonly performed exercises involving eccentric contractions may provide protection against exercise-induced muscle damage for subsequent bouts. [ABSTRACT FROM AUTHOR]

Quantifying the rate of metabolic energy expenditure (Ṁ) of varied aerobic exercise modalities is important for optimizing fueling and performance and maintaining safety in military personnel operating in extreme conditions. However, although equations exist for estimating oxygen uptake during running, surprisingly, there are no general equations that estimate Ṁ. Our purpose was to generate a general equation for estimating Ṁ during level running in healthy, military-age (18-44 years) women and men. We compiled indirect calorimetry data collected during treadmill running from 3 types of sources: original individual subject data (n=45), published individual subject data (30 studies; n5 421), and published group mean data (20 studies, n 5 619). Linear and quadratic equations were fit on the aggregated data set using a mixed-effects modeling approach. A chi-squared (η²) difference test was conducted to determine whether the more complex quadratic equation was justified (p < 0.05). Our primary indicator of model goodness-of-fit was the root-mean-square deviation (RMSD). We also examined whether individual characteristics (age, height, body mass, and maximal oxygen uptake [VO2max]) could minimize prediction errors. The compiled data set exhibited considerable variability in Ṁ (14.54 ± 3.52 W·kg-1), respiratory exchange ratios (0.8960.06), and running speeds (3.5060.86m·s-1). The quadratic regression equation had reduced residual sum of squares compared with the linear fit (η², 3,484; p, 0.001), with higher combined accuracy and precision (RMSD, 1.31 vs. 1.33 W·kg-1). Age (p 5 0.034), height (p 5 0.026), and body mass (p 5 0.019) were associated with the magnitude of under and overestimation, which was not the case for VO2max (p50.898). The newly derived running energy expenditure estimation (RE3) model accurately predicts level running Ṁ at speeds from 1.78 to 5.70 m·s21 in healthy, military-age women and men. Users can rely on the following equations for improved predictions of running Ṁ as a function of running speed (S, m·s-1) in either watts (W·kg-1 5 4.43 + 1.51·S + 0.37·S²) or kilocalories per minute (kcal·kg-1·min-1 = 308.8 + 105.2·S + 25.58·S²). [ABSTRACT FROM AUTHOR]

The Army Combat Fitness Test (ACFT) became the U.S. Army's mandatory physical fitness test in April of 2022. The purpose of this study was to determine the relationship between ACFT performance and both body composition and velocity profiles and to determine sex differences for these variables. Data were collected at 2 timepoints 4 months apart, from male (n = 55) and female (n = 17) Army Reserve Officers' Training Corps (ROTC) cadets. Body composition was assessed with a bioelectrical impedance spectroscopy device, and cadets completed a hex bar deadlift load-velocity profile (LVP) and ACFT on separate days. Stepwise multiple regressions were used to explain the amount of variance in ACFT total score and individual event performance. Significance for statistical tests was defined as an alpha level of p ≤ 0.05. Muscle mass and body fat percentage accounted for 49% of shared variance of total ACFT score, and deadlift maximal power and maximal velocity accounted for 67% of shared variance of total ACFT score. The 3 repetition maximum deadlift, standing power throw, hand-release push-up, and sprint-drag-carry events favored cadets with more muscle mass, whereas the leg tuck was influenced by the body fat percentage and the 2-mile run was affected by fat mass. Sex had greater predictive capability for the 2-mile run than body composition. Men outperformed women on all individual events, with the greatest differences on standing power throw and sprint-drag-carry. It is recommended that Army ROTC cadets taking the ACFT maximize lower-body power production and increase muscle mass. [ABSTRACT FROM AUTHOR]

Sansone, P, Rago, V, Kellmann, M, and Alcaraz, PE. Relationship between athlete-reported outcome measures and subsequent match performance in teamsports: A systematic review. J Strength Cond Res 37(11): 2302-2313, 2023--Athlete-reported outcome measures (AROMs; e.g., fatigue, stress, readiness, recovery, and sleep quality) are commonly implemented in team sports to monitor the athlete status. However, the relationship between AROMs and match performance indicators is unclear and warrants further investigation. This systematic review examined the relationship between precompetitive AROMs and subsequent match performances of team sport athletes. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, 3 (PubMed, Scopus, and Web of Science) databases were systematically searched to retrieve studies investigating the effects or association of AROMs and match: (a) technical-tactical performance (match-related statistics), (b) physical performance, (c) physiological and (d) perceptual demands, and (e) other measures of performance in adult team sport athletes. Quality assessment of included studies was performed using a modified Black and Downs checklist. Fifteen articles representing 289 team sport athletes were included. Mean quality of included studies was 7.661.0 (of 11). Across the included studies, 22 AROMs parameters were used, and 16 different statistical approaches were identified. Approximately 11 of 15 studies used nonvalidated AROMs. Overall, associations or effects of AROMs were found consistently for match-related statistics (7/9 studies), whereas results were unclear for physical performances (3/7 studies), perceptual demands (1/2 studies), or other measures of performance (2/4 studies). Considering the importance of keymatch-related statistics for success in teamsports, this reviewsuggests thatmonitoring precompetitive AROMs has potential to provide valuable information to coaches. However, it is indispensable to validate AROMs questionnaires and to uniform data collection and statistical procedures before substantiated indications to practitioners can be made. [ABSTRACT FROM AUTHOR]

The time-of-day effect of exercise on human function remains largely equivocal. Hence, this study aimed to further analyze the existing evidence concerning diurnal variations in cardiorespiratory responses and endurance performance using a meta-analytic approach. Literature search was conducted through databases, including PubMed, CINAHL, and Google Scholar. Article selection was made based on inclusion criteria concerning subjects' characteristics, exercise protocols, times of testing, and targeted dependent variables. Results on oxygen uptake (VO2), heart rate (HR), respiratory exchange ratio, and endurance performance in the morning (AM) and late afternoon or evening (PM) were extracted from the chosen studies. Metaanalysis was conducted with the random-effects model. Thirty-one original research studies that met the inclusion criteria were selected. Meta-analysis revealed higher resting VO2 (Hedges' g = -0.574; p = 0.040) and resting HR (Hedges' g= -1.058; p = 0.002) in PM than in AM. During exercise, although VO2 remained indifferent between AM and PM, HR was higher in PM at submaximal (Hedges' g = -0.199; p = 0.046) and maximal (Hedges' g = -0.298; p = 0.001) levels. Endurance performance as measured by time-to-exhaustion or the total work accomplished was higher in PM than in AM (Hedges' g = -0.654; p = 0.001). Diurnal variations in VO2 appear less detectable during aerobic exercise. The finding that exercising HR and endurance performance were greater inPMthan in AMemphasizes the need to consider the effect of circadian rhythm when evaluating athletic performance or using HR as a criterion to assess fitness or monitor training. [ABSTRACT FROM AUTHOR]

Animal studies show that long-lasting stretching training can lead to significant hypertrophy and increases in maximal strength. Accordingly, previous human studies found significant improvements in maximal voluntary contraction (MVC), flexibility, and muscle thickness (MTh) using constant angle long-lasting stretching. It was hypothesized that long-lasting stretching with high intensity will lead to sufficient mechanical tension to induce muscle hypertrophy and maximal strength gains. This study examined muscle cross-sectional area (MCSA) using magnetic resonance imaging (MRI). Therefore, 45 well-trained subjects (f: 17, m: 28, age: 27.7 ± 3.0 years, height: 180.8 ± 4.9 cm, mass: 80.467.2 kg) were assigned to an intervention group (IG) that stretched the plantar flexors 6 x 10 minutes per day for 6 weeks or a control group (CG). Data analysis was performed using 2-way ANOVA. There was a significant Time x Group interaction in MVC (p < 0.001-0.019, η² = 0.158-0.223), flexibility (p < 0.001, η² = 0.338-0.446), MTh (p = 0.002-0.013, η² = 0.125-0.172), and MCSA(p = 0.003-0.014, η² =0.143-0.197). Post hoc analysis showed significant increases inMVC(d = 0.64-0.76), flexibility (d = 0.85-1.12), MTh (d = 0.53-0.6), and MCSA (d = 0.16-0.3) in IG compared with CG, thus confirming previous results in well-trained subjects. Furthermore, this study improved the quality for the morphological examination by investigating both heads of the gastrocnemius with MRI and sonography. Because stretching can be used passively, an application in rehabilitation settings seems plausible, especially if no commonly used alternatives such as strength training are applicable. [ABSTRACT FROM AUTHOR]

The squat is used to enhance performance and rehabilitate the lower body. However, muscle forces and how muscles accelerate the center of mass (CoM) are not well understood. The purpose was to determine how lower extremity muscles contribute to the vertical acceleration of the CoM when squatting to parallel using 85% one-repetition maximum. Thirteen female subjects performed squats in a randomized fashion. Musculoskeletal modeling was used to obtain muscle forces and muscle-induced accelerations. The vasti, soleus, and gluteus maximus generated the largest upward accelerations of the CoM, whereas the muscles that produced the largest downward acceleration about the CoM were the hamstrings, iliopsoas, adductors, and tibialis anterior. Our findings indicate that a muscle's function is task and posture specific. That is, muscle function depends on both joint position and how an individual is interacting with the environment. [ABSTRACT FROM AUTHOR]

This study aimed to investigate if external training load metrics differ between training days and match day (MD) during a period of fixture congestion and to verify if external load metrics vary based on playing positions. Training and MD data were collected in a part of the competition phase of the 2020-2021 season (6 weeks) in the English Football League 2 (N = 20 players, mean ± SDs: age = 24.4 ± 4.7 years). Global Navigation Satellite System units (Catapult S7 Vector 10 Hz) were used to monitor external load metrics. The metrics were duration of training, total distance (TD), high-speed running distance (HSR), sprinting distance, relative intensity (m/min), total accelerations (TotAcc) (>3 m⋅s-2), and total decelerations (TotDec) (<-3 m⋅s-2). This study found that duration, TD, relative intensity, HSR distance, sprint distance, TotAcc, and TotDec were different (p < 0.001, d = small to moderate) between MD and match day minus two (MD-2) or match day minus one (MD-1); however, during match day minus four (MD-4), only relative intensity was significantly lower (p < 0.001) compared with MD output. Therefore, MD-4 was the most demanding training session of the week (after the MD), and during MD-2 and MD-1, coaches decreased players' load to favor players' readiness. Moreover, this study found that MD and MD-1 resulted in statistically different values across several metrics between different playing positions (defenders < midfielders and strikers), whereas metrics in MD-4 and MD-2 were not statistically different, which highlights that in these sessions, players have similar external loads independently from their playing positions. [ABSTRACT FROM AUTHOR]

The effectiveness of offensive ball carrying has been identified as a key determinant in elite rugby union try-scoring success and subsequent match outcome. Despite this, there is limited research evaluating the physical qualities believed to underpin the ball-carrying capability among elite rugby union players. The aim of this review was to critically appraise the scientific literature that has investigated the use of physical characteristics to explain ball-carrying capability in elite rugby union. Measures of sprint performance, specifically acceleration, maximum sprinting speed, and sprint momentum have presented weak-to-strong correlations with the number of tries scored, line breaks, tackle breaks, defenders beaten, and dominant collisions recorded among international rugby union players. In addition, unilateral and bilateral vertical countermovement jump height, peak power output, and drop jump reactive strength index have each demonstrated meaningful associations with the number of tries scored, line breaks, tackle breaks, and dominant collisions. However, various measures of maximal lower-body strength have presented only trivial correlations with the game statistics associated with ball-carrying capability. These trivial correlations are likely a result of the inconsistent and inaccurate methods used to assess maximal lower-body strength, with methods ranging from a box squat-predicted 1 repetition maximum to a maximal isometric mid-thigh pull. Further investigation is required to assess the contribution of maximal lower-body strength, agility, repeated sprint ability, and aerobic capacity to ball-carrying capability in elite rugby union. Such robust, objective data could be used to inform the specificity of physical preparation and maximize the transfer of these physical qualities to on-field performance. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the test-retest reliability, usefulness, and validity of field-based devices, in determining jump height (JH) during a countermovement jump (CMJ). Twenty-one male (22.8 ± 2.4 years; 1.82 ± 0.07 m; 86.0 ± 10.4 kg) and 7 female field sport athletes (20.5 ± 1.5years; 1.65 ± 0.06 m; 65.4 ± 7.2 kg) performed 3 CMJs with data simultaneously recorded using a force plate (criterion measure), Optojump, Output Capture, and Push-Band 2.0. Reliability was determined by intraclass correlation (ICC) and coefficient of variation (CV) analyses. Usefulness was assessed by comparing typical error (TE) with the smallest worthwhile change (SWC), and the validity analyses involved repeated measures analysis of variance with post hoc analysis, Pearson correlation coefficient (r), coefficient of determination, and Bland-Altman 95% limits of agreement analyses. All 3 field-based devices were deemed reliable in assessing CMJ height as the respective ICCs ≥ 0.80 and the CV ≤ 10%. Only the Optojump and Output Capture devices were rated as "good" at detecting the SWC in performance (Optojump SWC: 1.44 > TE: 1.04; Output Capture SWC: 1.47 > TE: 1.05). The Output Capture device demonstrated acceptable validity for CMJ height assessment, whereas the Push-Band 2.0 showed systematic bias when compared with the criterion force plate data. Systematic difference was also evident for the Optojump potentially due to the optical switching-cell position on the Optojump. Although all 3 devices showed excellent reliability, the Optojump and Output Capture devices offer practitioners a cost effective, reliable, and valid method of assessing the smallest worthwhile change in CMJ performance in an applied setting. [ABSTRACT FROM AUTHOR]

The increased participation in trail running (TR) races and the emergence of official international races have increased the performance level of the world best trail runners. The aim of this study was to compare cost of running (Cr) and biomechanical and neuromuscular characteristics of elite trail runners with their lower level counterparts. Twenty elite (10 females; ELITE) and 21 experienced (10 females; EXP) trail runners participated in the study. Cr and running biomechanics were measured at 10 and 14 km·h-1 on flat and at 10 km·h-1 with 10% uphill incline. Subjects also performed maximal isometric voluntary contractions of knee and hip extensors and knee flexors and maximal sprints on a cycle ergometer to assess the power-torque-velocity profile (PTVP). Athletes also reported their training volume during the previous year. Despite no differences in biomechanics, ELITE had a lower Cr than EXP (p < 0.05). Despite nonsignificant difference in maximal lower-limb power between groups, ELITE displayed a greater relative torque (p < 0.01) and lower maximal velocity (p < 0.01) in the PTVP. Females displayed shorter contact times (p < 0.01) compared with males, but no sex differences were observed in Cr (p > 0.05). No sex differences existed for the PTVP slope, whereas females exhibited lower relative torque (p < 0.01) and velocity capacities (p < 0.01) compared with males. Although not comprehensively assessing all determining factors of TR performance, those data evidenced level and sex specificities of trail runners in some factors of performance. Strength training can be suggested to lower level trail runners to improve Cr and thus TR performance. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the effects of different rest interval lengths (RILs) on repetition performance, rating of discomfort, and blood lactate responses during lower-body single-joint and multijoint exercises. This study used a counterbalanced design where each subject performed the Smith machine back squat (BS) and leg extension (LE) using 3 different RIL configurations (1, 2, and 3 minutes) in a randomized fashion. Data collection occurred over the span of 3 separate days. Volunteers were randomly allocated to perform the independent variables (RILs and exercises) in 1 of 12 potential configurations. The initial session was allotted for familiarization with the rating of discomfort scale and 10 repetition maximum testing. The other 2 sessions involved training with the different configurations of RIL length using both the BS and LE. Randomization ensured that the BS was performed first in one of the training sessions and the LE was performed first in the other session. Results indicated that longer RILs had a small positive effect on repetition performance, with longer rest durations allowing for more repetitions compared with shorter durations. The largest difference in repetition performance between RILs was observed between 1 minute and 2-3 minutes rest; there were trivial differences in repetition performance between 2 and 3 minutes rest for both the BS and LE. Blood lactate levels were slightly higher with longer RILs. Overall, BS showed greater increases in blood lactate compared with LE, and these differences were magnified over time. Exercise selection and RIL both influenced rating of discomfort, with LE producing less discomfort than BS and longer RILs reducing perceived discomfort. Our findings suggest that RIL influences the repetition performance, blood lactate, and rating of discomfort responses between single-joint and multijoint exercises. [ABSTRACT FROM AUTHOR]

The origins of weightlifting and feats of strength span back to ancient Egypt, China, and Greece, with the introduction of weightlifting into the Olympic Games in 1896. However, it was not until the 1950s that training based on weightlifting was adopted by strength coaches working with team sports and athletics, with weightlifting research in peerreviewed journals becoming prominent since the 1970s. Over the past few decades, researchers have focused on the use of weightlifting-based training to enhance performance in nonweightlifters because of the biomechanical similarities (e.g., rapid forceful extension of the hips, knees, and ankles) associated with the second pull phase of the clean and snatch, the drive/thrust phase of the jerk and athletic tasks such as jumping and sprinting. The highest force, rate of force development, and power outputs have been reported during such movements, highlighting the potential for such tasks to enhance these key physical qualities in athletes. In addition, the ability to manipulate barbell load across the extensive range of weightlifting exercises and their derivatives permits the strength and conditioning coach the opportunity to emphasize the development of strength-speed and speed-strength, as required for the individual athlete. As such, the results of numerous longitudinal studies and subsequent meta-analyses demonstrate the inclusion of weightlifting exercises into strength and conditioning programs results in greater improvements in force-production characteristics and performance in athletic tasks than general resistance training or plyometric training alone. However, it is essential that such exercises are appropriately programmed adopting a sequential approach across training blocks (including exercise variation, loads, and volumes) to ensure the desired adaptations, whereas strength and conditioning coaches emphasize appropriate technique and skill development of athletes performing such exercises. [ABSTRACT FROM AUTHOR]

Sport climbing was selected to be part of the Summer Olympic Games in Tokyo 2021 with 3 subdisciplines: lead climbing, speed climbing, and bouldering. The nature of physical effort while speed climbing, lead climbing, and bouldering performance is different. This literature review aimed to describe differences between body composition, anthropometric parameters, and upper-limb strength-endurance variables between sport climbers with different ability levels and nonclimbers. The following databases were searched: PubMed and Scopus. The following keywords were used: "sport climbing," "rock climbing," "lead climbing," and "bouldering." Articles were considered from January 2000 to October 2021 if they concerned at least one of the following parameters: body composition (mass, body mass index, body fat, lean muscle mass, bone mineral density), anthropometric parameters (height, ape index), muscle strength (MVC finger strength in half-crimp grip, MVC finger strength to body mass, handgrip strength), and muscle endurance (force time integral, pull-ups). A review shows that body mass and body fat content were lower in the sport climbers compared with controls and in elite sport climbers compared with those less advanced. Sport climbers presented higher values of MVC finger strength in half-crimp grip, MVC finger strength to body mass, handgrip strength, and force time integral parameter than control subjects. Significantly higher MVC values in half-crimp grip were observed in elite sport climbers than in advanced athletes. None of the analyzed work showed differences between sport climber groups in the ape index. The abovementioned parameters may be a key factor in elite sport climbing performance. [ABSTRACT FROM AUTHOR]

This study determined stroke and movement accelerometry metrics from a wearable sensor and compared between court surface (grass vs. hard) and match outcome (win vs. loss) during competitive tennis match-play. Eight junior high-performance tennis players wore a trunk-mounted global positioning system, with in-built accelerometer, magnetometer, and gyroscope during singles matches on hard and grass courts. The manufacturer software calculated accelerometer-derived total player load (tPL). A prototype algorithm classified forehands, backhands, serves, and "other" strokes, thereby calculating stroke PL (sPL) from individual strokes. Movement PL (mPL) was calculated as the difference between tPL and sPL, with all metrics reported as absolute and relative (min-1, %, and ·stroke). Analysis of accelerometer load and stroke count metrics was performed through a two-way (surface [grass vs. hard] × match outcome [win vs. loss]) analysis of variance (p < 0.05) and effect sizes (Cohen's d). No interaction effects for surface and match outcome existed for absolute tPL, mPL, and sPL (p > 0.05). Increased mPL% featured on grass courts, whereas sPL% was increased on hard courts (p = 0.04, d = 1.18[0.31-2.02]). Elevated sPL·min-1 existed on hard courts (p = 0.04, d = 1.19[0.32-2.04]), but no differences in tPL·min-1 and mPL·min-1 were evident for surface or outcome (p > 0.05). Relative forehand sPL (FH-sPL·min-1) was higher on hard courts (p = 0.03, d = 1.18[0.31-2.02]) alongside higher forehand counts (p = 0.01, d = 1.29[0.40-2.14]). Hitting demands are heightened on hard courts from increased sPL and counts. Conversely, increased mPL% on grass courts likely reflects the specific movement demands from point-play. Physical preparation strategies during training blocks can be tailored toward movement or hitting loads to suit competitive surfaces. [ABSTRACT FROM AUTHOR]

The article introduces various reports published within the issue which were submitted by scientists who attended the second International Congress on Soldiers' Physical Performance in Jyväskylä, Finland on May 4-7, 2011.

The aim of this study was to compare the acute cardiovascular and neuromuscular effects of 3 time-matched sessions of high-intensity training. Eighteen moderately active adults (9 women and 9 men [age: 23 ± 2.9 years; maximum oxygen consumption (V̇O2max): 47.6 ± 4.1 ml·kg-1 ·min-1 ]) performed three low-volume (;9 minutes) sessions in a randomized order: sprint interval training (SIT), burpee interval training (BIT) (10 × 5 seconds efforts × 35 seconds recovery), and vigorous intensity continuous training (VICT) (6 minutes 5 seconds of running at ;85% of peak heart rate [HRpeak]). Indices related to heart rate (HR), neuromuscular performance (counter movement jump height [CMJheight] and squat and bench press power), and autonomic balance (heart rate recovery and heart rate variability [HRR and HRV] )were monitored during exercise. Sprint interval training and VICT elicited a higher HRmean (171.3 ± 8.4 and 166.5 ± 7.5 vs. 150.5 ± 13.6 b·min-1, p < 0.001) and time of ≥90%HRpeak (133.3 ± 117.4 and 110 ± 128.9 vs. 10 ± 42.4 seconds, p < 0.01) than BIT. Sprint interval training exhibited a slower HRR and lower HRV than BIT and VICT (p < 0.05) postsession. Moreover, only SIT resulted in a significant decline (p < 0.01) in CMJheight (34.7 ± 7.2 to 33.5 ± 7.2 cm), relative squat mean power (25.5 ± 4.5 to 23.8 ± 4.9 W·kg-1 ), and relative bench press peak power (6.9 ± 2.4 to 6.2 ± 2.5 W·kg-1 ). Results revealed that SIT diminishes the sympathovagal reactivation and neuromuscular performance compared with work-matched BIT and VICT. [ABSTRACT FROM AUTHOR]

Essentrics is a dynamic full-body stretching workout, which has recently earned its popularity in the field of yoga because of its potential for improvement in balance, flexibility, and weight loss while adding enjoyment to the workout without any discomfort and pain. However, the effects of Essentrics on overall health have not been well studied, particularly in a younger, physically healthy population. Thirty-five subjects (27 females and 8 males, age = 20.4 ± 0.2 years, and body mass index 5 22.58 ± 0.55 kg·m-2 ) were assigned to 2 groups—contemporary western yoga (CWY, n = 20) and Essentrics (ESS, n = 15). Each group met 3 times per week for a total of 45–50 minutes per day for 6 weeks. Anthropometric measurements, body composition (dual-energy x-ray absorptiometry), flexibility (sit-and-reach), and balance (lower extremity Y-balance) were assessed before and after the 6-week program. The balance test included 3 reaches (anterior, posteromedial [PM], and posterolateral [PL] and composite reach distance). Each reach was averaged for the right and left sides and then normalized to leg length. Data were analyzed using an analysis of variance with repeated measures (p ≤ 0.05), and a post hoc test was performed for any significant interactions. There were no significant group differences between CWY and ESS in balance and flexibility. Following the 6-week yoga programs, balance was improved as follows: PM (87.13 ± 11.64 cm to 92.25 ± 9.91 cm, p = 0.001), PL (82.88 ± 11.28 to 88.62 ± 9.62 cm, p = 0.002), composite reach distance (CRD) (225.96 ± 27.17 to 238.26 ± 22.98 cm, p = 0.001), normalized PM (98.31 ± 11.68 to 104.27 ± 11.14%, p = 0.001), normalized PL (93.60 ± 11.98 to 100.15 ± 10.70%, p = 0.001), and normalized CRD (255.12 ± 27.89 to 269.21 ± 25.07%, p = 0.001). Flexibility was also improved from 51.42 ± 8.24 to 53.38 ± 7.04 cm (p = 0.010) following the 6-week workout programs. Total body fat percentage was significantly reduced only in the CWY group (24.44 ± 6.73 to 23.51 ± 6.32%, p = 0.002). Regardless of the type of stretching workout, both dynamic and static workouts improved flexibility and balance. Thus, individuals seeking to improve balance and flexibility can benefit from either dynamic or static yoga program. [ABSTRACT FROM AUTHOR]

This project examined the differences between a single set (SS) compared to multiple sets (MS) of resistance exercise on the Akt/protein kinase B (PKB) signaling pathway, the expression of insulin-like growth factor-1 (IGF-1), and the receptor for IGF-1 (IGF-1R) to better understand the types of resistance training protocols that are most beneficial in stimulating the muscle hypertrophic response. Sixteen healthy men were randomly selected into 2 groups of 8. Subjects in each group received 3 biopsies: (a) before exercise, (b) 15 minutes postexercise, and (c) 180 minutes postexercise. Subjects in the SS group performed 1 set of leg press to failure at 80% of their predetermined 1 repetition maximum (1RM). Subjects in the MS group performed 2 sets of 10 repetitions and 1 set to failure at 80% of their predetermined 1RM, with 3 minutes of rest between each set. Our results indicated no group 3 time interactions in the concentration of Akt signaling proteins. Furthermore, there were no group 3 time interactions in IGF-1 or IGF-1R expression. However, phosphorylated 4E-binding protein 1 levels increased 150% from pre to 180 minutes post (p = 0.005). In addition, there was a significantly greater increase in IGF-1R expression in the SS group compared with the MS group (7.99±10.07 vs. 4.41 ± 6.28; p = 0.026). Collectively, we found that a SS of resistance training evokes a similar acute Akt/PKB pathway response as MS in recreationally active men. [ABSTRACT FROM AUTHOR]

Youth sport is associated with the identification and promotion of athletes within talent development pathways, with anthropometric and physical performance measures being key assessment and monitoring tools. To adequately evaluate performance within a population, normative reference data are needed; however, currently, there is limited normative values of talent-identified youth athletes. The aim of the current study is to present normative values of talent-identified youth sport academy athletes in relation to gender, age, and sport. Over a 5-year period, a total of 794 talent-identified youth athletes who attended a specialized school sports academy were assessed using anthropometric (i.e., heigh,; body mass) and physical performance (i.e., vertical jump, 20-m sprint, Yo-Yo intermittent recovery test 1) measures. In total, 451 male and 343 female athletes (grade 7: 12-13 years; grade 8: 13-14 years; grade 9: 14-15 years; grade 10: 15-16 years) were tested annually. The result demonstrates that for each gender, as age increases, there is a general increase in anthropometric measures (i.e., height and body mass). Furthermore, with increasing age, athletes generally have a higher vertical jump, faster sprint performance, and improved physical endurance. The results highlight sport-specific differences for each measure. Overall, the results of the study provides age-, gender-, and sport-specific normative data of talent-identified youth athletes. These findings provide representative performance profiles of talent-identified high school athletes, with the values potentially being used by coaching staff (i.e., head coaches, strength and conditioning coaches, rehabilitation staff) for comparison purposes. [ABSTRACT FROM AUTHOR]

The aim of this brief narrative review is to summarize the present evidence, provide recommendations for data analysis, and provide appropriate training methods to reduce strength and power asymmetries within athlete populations. Present evidence shows that a strong interest in the assessment of asymmetry exists. Despite the perceived associated relationship between asymmetry and injury and performance, a clear link is still missing. Practitioners need to be aware of this when they decide to assess asymmetries and later design training interventions. Several bilateral and unilateral tests could be used to assess asymmetries, such as isokinetic dynamometry, the isometric mid-thigh pull, squat, and Nordic hamstring exercise. Based on the current evidence, future investigations require further standardization of methodology and analysis to optimize interpretation (e.g., within session and between session), adoption, and implementation of interlimb asymmetry testing and appropriate interventions. In this review, 3 training interventions have been proposed to reduce existing lower limb asymmetries in sport populations: traditional resistance training, flywheel resistance training, and combined training interventions, with some evidence suggesting that such interventions can reduce lower limb asymmetries. Nonetheless, the number and quality of articles currently available are too limited to draw firm conclusions; therefore, further research is needed to verify whether training interventions can achieve these aims. To develop an understanding and application of interventions addressing interlimb asymmetries within the sport, greater methodological rigor should be applied toward study design, data analysis, and interpretation of future investigations and when appraising the current literature. [ABSTRACT FROM AUTHOR]

This study compared the movement- and stroke-related accelerometer profiles and stroke counts between common on-court tennis training drills. Ten, junior-elite, male tennis players wore a cervical-mounted global positioning systems, with in-built accelerometer, gyroscope, and magnetometer during hard court training sessions (n = 189). Individual training drills were classified into 8 categories based on previous research descriptions. Manufacturer software calculated total player load (tPL), while a prototype algorithm detected forehand (FH), backhands (BH), and serves and then calculated a stroke player load (sPL) from individual strokes. Movement player load (mPL) was calculated as the difference between tPL and sPL. Drill categories were compared for relative (.min-1) tPL, sPL, mPL, and stroke counts via a 1-way analysis of variance with effect sizes (Cohen's d) and 95% confidence intervals. Highest tPL.min-1 existed in accuracy and recovery or defensive drills (p < 0.05), with lowest tPL·min-1 values observed in match-play simulation (p < 0.05). For sPL·min-1, accuracy drills elicited greater values compared with all other drill types (p < 0.05), partly via greater FH-sPL·min-1 (p < 0.05), with lowest sPL·min-1 existing for match-play (p < 0.05). Accuracy, open, and recovery or defensive drills result in greater BH-sPL·min-1 and BH.min-1 (p < 0.05). Serve-sPL·min-1 is highest in technical and match-play drills (p < 0.05). Higher mPL·min-1 existed in accuracy, recovery or defensive, 2v1 net, open, and 2v1 baseline (p < 0.05). Furthermore, mPL·min-1 in points drills was greater than technical and match-play simulation drills (p < 0.05). Higher hitting-based accelerometer loads (sPL·min-1) exist in accuracy drills, whereas technical and match-play drills show the lowest movement demands (mPL·min-1). These findings can aid individual drill prescription for targeting movement or hitting load. [ABSTRACT FROM AUTHOR]

Carson, F, Blakey, M, Foulds, SJ, Hinck, K, and Hoffmann, SM. Behaviors and actions of the strength and conditioning coach in fostering a positive coach-athlete relationship. J Strength Cond Res 36(11): 3256–3263, 2022—A number of models have been developed to explain the various factors that affect coach-athlete interactions; however, they have had limited application to strength and conditioning (S&C). A systematic review of the literature was completed using the databases SPORTDiscus Full Text, MEDLINE, Global Health, Academic Search Complete, and PsychINFO, sourcing articles related to S&C coach-athlete relationships. An initial search yielded 1,364 articles, which when screened against the inclusion criteria was narrowed to 8 articles relating specifically to the S&C coach-athlete relationship. Four major themes were identified throughout the included articles: leadership styles; perceptions of leadership; coach knowledge, experience, and training; and building relationships. These themes highlighted that positive coach-athlete interactions are fostered through a mutual understanding of the S&C coach's responsibility to improve performance and reduce injury through scientific methods, with an awareness of different psychosocial behaviors of both the coach and the athlete. This will create a mutual interconnectedness whereby both parties can participate in a functional dyad. Three practical applications deduced from the findings identified the importance of building an autonomy-supportive environment, keeping knowledge and expertise at a high standard, and embracing the whole person rather than just the athlete. These teachings aim to guide S&C coaches through the necessary actions and behaviors recommended to successfully build and foster positive S&C coach-athlete relationships. [ABSTRACT FROM AUTHOR]

Lambrianides, Y, Epro, G, Smith, K, Mileva, K, James, D, and Karamanidis, K. Impact of different mechanical and metabolic stimuli on the temporal dynamics of muscle strength adaptation. J Strength Cond Res 36(11): 3246–3255, 2022—A fundamental task in exercise physiology is to determine and ultimately improve the adaptations that take place in the human body, an integrated network of various physiological systems, for example, muscle, tendon, and bone. Investigating the temporal dynamics (time course) of adaptations in these diverse systems may help us gain new knowledge about the functioning of the neuromotor system in healthy and pathological conditions. The aim of this review was to explore the temporal dynamics of muscular strength adaptations in studies implementing a resistance training intervention. In addition, we categorized these studies under mechanical or metabolic stimuli to identify whether certain stimuli cause faster muscle strength gains. Searches were performed using PubMed and Google Scholar databases. The review comprised 708 subjects from 57 training groups within 40 studies that met the inclusion criteria. The results revealed that the mean time point of first significant increase in muscle strength of all studies was 4.3 weeks, and the corresponding increase was on average about 17%. A plateau in muscle strength increase (∼25%) was found to occur between weeks 8 and 12. Categorization into stimuli groups revealed that performing training in a hypoxic environment is likely to produce a leftward shift (∼25% increase at ∼2.8 weeks) in the dose-response relationship compared with blood flow restriction and supplementation. However, stimuli that cause faster muscle strength gains may also induce imbalanced adaptation between the muscle and the surrounding biological structures, potentially triggering a degradation in some parts of the network (i.e., leading to an increased risk of injury). [ABSTRACT FROM AUTHOR]

Kiely, M, Warrington, G, McGoldrick, A, and Cullen, S. Physical preparation strategies of professional jockeys. J Strength Cond Res 36(11): 3184–3189, 2022—Professional horse racing is a physically demanding sport. The aim of the study was to examine the physical preparation strategies of jockeys for racing. A questionnaire was developed and validated which comprised of 4 sections; (a) background information, (b) making weight and current associated exercise habits, (c) current physical activity practices, and (d) jockey perceptions of strength and conditioning (S&C) and current practices. Eighty-five jockeys (n = 38 professional flat, n = 47 professional jump) completed the questionnaire in race course weighing rooms representing 80% of the professional athlete population. In total, 77.6% of jockeys participate in physical activity outside of riding. Jockeys that participated in S&C (42.4%) reported their most frequent type of S&C practice; cardio (52.8%), high-intensity interval training (33.3%), flexibility and mobility training (8.3%), resistance training (5.6%). There was no significant difference in S&C participation between total flat and total jump licenses (p = 0.530; [PHI] = 0.068). Difficulty making weight was reported by 55.3% of jockeys. Exercise alone was used by 29.4% of jockeys to rapidly reduce weight. There was no significant difference (p = 0.201, [PHI] = 0.357) between the frequency of rapid weight loss per month for total flat (1.7 ± 1.7) and total jump jockeys (1.6 ± 0.5). This study represents the only published data on the physical preparation strategies of jockeys. Jockeys do not partake in physical activity, which mimics the repeated high-intensity demands of racing. Future research is required to examine the effects of specific S&C interventions on riding performance. [ABSTRACT FROM AUTHOR]

Supplemental Digital Content is Available in the Text. Rodriguez, C, Harty, PS, Stratton, MT, Siedler, MR, Smith, RW, Johnson, BA, Dellinger, JR, Williams, AD, White, SJ, Benavides, ML, and Tinsley, GM. Comparison of indirect calorimetry and common prediction equations for evaluating changes in resting metabolic rate induced by resistance training and a hypercaloric diet. J Strength Cond Res 36(11): 3093–3104, 2022—The ability to accurately identify resting metabolic rate (RMR) changes over time allows practitioners to prescribe appropriate adjustments to nutritional intake. However, there is a lack of data concerning the longitudinal utility of commonly used RMR prediction equations. The purpose of this study was to evaluate the validity of several commonly used prediction equations to track RMR changes during a hypercaloric nutritional intervention and supervised resistance exercise training program. Twenty resistance-trained men completed the study. The protocol lasted 6 weeks, and subjects underwent RMR assessments by indirect calorimetry (IC) preintervention and postintervention to obtain reference values. Existing RMR prediction equations based on body mass (BM) or dual-energy X-ray absorptiometry fat-free mass (FFM) were also evaluated. Equivalence testing was used to evaluate whether each prediction equation demonstrated equivalence with IC. Null hypothesis significance testing was also performed, and Bland-Altman analysis was used alongside linear regression to assess the degree of proportional bias. Body mass and FFM increased by 3.6 ± 1.7 kg and 2.4 ± 1.6 kg, respectively. Indirect calorimetry RMR increased by 165 ± 97 kcal·d−1, and RMR:FFM increased by 5.6 ± 5.2%. All prediction equations underestimated mean RMR changes relative to IC, with magnitudes ranging from 75 to 155 kcal·d−1, while also displaying unacceptable levels of negative proportional bias. In addition, no equation demonstrated equivalence with IC. Common RMR prediction equations based on BM or FFM did not fully detect the increase in RMR observed with resistance training plus a hypercaloric diet. Overall, the evaluated prediction equations are unsuitable for estimating RMR changes in the context of this study. [ABSTRACT FROM AUTHOR]

Dünnwald, T, Morawetz, D, Faulhaber, M, Gatterer, H, Birklbauer, C, Koller, A, Weiss, G, and Schobersberger, W. Supplemental O2 during recovery does not improve repeated maximal concentric-eccentric strength-endurance performance in hypoxia. J Strength Cond Res 36(11): 3065–3073, 2022—An alpine ski racing training session typically includes repeated bouts of maximal exercise at high altitude. We evaluated whether hyperoxic recovery between 5 sets of high-intensity strength-endurance exercises, which resembled ski racing activity and were performed in hypoxia, has beneficial effects on performance and acid-base status. In this randomized, single blinded crossover study, 15 highly skilled ski athletes (4 f/11 m; 29.7 ± 5.7 years) performed 5 90 seconds flywheel sets (S) in a normobaric hypoxic chamber (3,500 m). The flywheel sets were separated by 4 15-minute recovery periods. During recovery, subjects received either 100% O2 (hyperoxic setting [HS]) or hypoxic air (nonhyperoxic setting [NHS]; FiO2: 0.146). Performance outcomes (e.g., power output [PO], concentric peak power [Conpeak], and eccentric peak power [Eccpeak]) and physiological parameters (e.g., heart rate, blood gases, and blood lactate) were evaluated. Mean PO, Conpeak, and Eccpeak from S1 to S5 did not differ between settings (146.9 ± 45 W and 144.3 ± 44 W, 266.9 ± 80 W and 271.2 ± 78 W, and 271.0 ± 93 W and 274.1 ± 74 W for HS and NHS, respectively; p ≥ 0.05). SpO2, PaO2, and CaO2 were higher during recovery in HS than in NHS (p ≤ 0.001). Lactate levels were significantly lower in the last recovery phase in HS than in NHS (p = 0.016). Hyperoxic recovery has no impact on performance in a setting resembling alpine ski racing training. Positive effects on arterial oxygen content and cellular metabolism, as indicated by reduced blood lactate levels during recovery in the hyperoxic setting, seem to be insufficient to generate a direct effect on performance. [ABSTRACT FROM AUTHOR]

Martínez-Gómez, MG and Roberts, BM. Metabolic adaptations to weight loss: A brief review. J Strength Cond Res 36(10): 2970–2981, 2022—As the scientific literature has continuously shown, body mass loss attempts do not always follow a linear fashion nor always go as expected even when the intervention is calculated with precise tools. One of the main reasons why this tends to happen relies on our body's biological drive to regain the body mass we lose to survive. This phenomenon has been referred to as "metabolic adaptation" many times in the literature and plays a very relevant role in the management of obesity and human weight loss. This review will provide insights into some of the theoretical models for the etiology of metabolic adaptation as well as a quick look into the physiological and endocrine mechanisms that underlie it. Nutritional strategies and dietetic tools are thus necessary to confront these so-called adaptations to body mass loss. Among some of these strategies, we can highlight increasing protein needs, opting for high-fiber foods or programming-controlled diet refeeds, and diet breaks over a large body mass loss phase. Outside the nutritional aspects, it might be wise to increase the physical activity and thus the energy flux of an individual when possible to maintain diet-induced body mass loss in the long term. This review will examine these protocols and their viability in the context of adherence and sustainability for the individual toward successful body mass loss. [ABSTRACT FROM AUTHOR]

Supplemental Digital Content is Available in the Text. Chang, C-C, Chang, C-M, and Shih, Y-F. Kinetic chain exercise intervention improved spiking consistency and kinematics in volleyball players with Scapular Dyskinesis. J Strength Cond Res 36(10): 2844–2852, 2022—Scapular dyskinesis (SD) is a common problem among volleyball players with chronic shoulder pain. This randomized controlled study examined the effectiveness of kinetic chain (KC) training on neuromuscular performance of the scapula and trunk during volleyball spikes. Forty volleyball players with SD and chronic shoulder pain received 4 weeks of KC training or the conventional shoulder exercise training (CT). Shoulder pain was assessed using the visual analogue scale (VAS) every week. The kinematics and muscle activation of the shoulder and upper trunk, and proprioceptive feedback magnitude (PFM) for scapular movement consistency, were recorded at the maximum shoulder flexion (T1) and ball contact (T2) during spiking tasks. The two-way repeated measures analysis of variances was used to assess the between-group differences before and after the intervention. The results showed a significant time by group interaction for the upper trunk rotation (p < 0.001) and PFM (p = 0.03) at T2. The post-hoc test indicated that the KC group significantly increased contralateral rotation of the upper trunk (9.63 ± 4.19° vs. −4.25 ± 10.05°), and improved movement consistency (error: 8.88 ± 11.52° vs. 19.73 ± 12.79°) at T2 compared with the CT group. Significant time effects were also identified for VAS, scapular upward rotation (T1 and T2), upper trunk contralateral side-bending and PFM at T1, and upper trunk contralateral rotation at T2. In conclusion, both KC and CT training would relieve shoulder pain and improve scapular and trunk movement, whereas the KC program was more effective for increasing scapular movement consistency and upper trunk rotation during volleyball spikes. [ABSTRACT FROM AUTHOR]

Hackett, DA. Influence of movement velocity on accuracy of estimated repetitions to failure in resistance-trained men. J Strength Cond Res 36(10): 2701–2708, 2022—This study explored the accuracy in estimated repetitions to failure (ERF) and changes in mean concentric velocity (MCV) during resistance exercise. Twenty male resistance trainers (age, 26.3 ± 6.9 years; body mass, 82.0 ± 6.0 kg; stature, 178.0 ± 5.5 cm) completed 5 sets of 10 repetitions for the bench press and squat at 70% one-repetition maximum. Subjects' reported their rating of perceived exertion (RPE) and ERF after the 10th repetition of each set and then continued repetitions to momentary muscle failure (5-minute recovery between sets). Barbell velocity was assessed using a linear position transducer. For the bench press, MCV at repetitions 9–10 decreased as sets progressed (p ≤ 0.005) with a greater loss of MCV for sets 3–5 vs. set 1 (p ≤ 0.005). No significant changes in MCV variables were found across sets for the squat. Error in ERF was greater in set 1 for the bench press (p ≤ 0.005) with no differences for the remaining sets. There were no differences between sets for error in ERF for the squat. Moderate to strong relationships were found between most MCV variables and RPE and ERF, for the bench press (r s = −049 to 0.73; p ≤ 0.005). For the squat only, MCV at repetitions 9–10 was moderately related with RPE (r s = −0.33; p ≤ 0.003) and actual repetitions to failure (r s = 0.31; p ≤ 0.003). No significant relationships were found for error in ERF for either the bench press or squat. Changes in MCV across sets may influence perception of effort and performance for the bench press; however, it does not influence the accuracy in ERF for either exercise. [ABSTRACT FROM AUTHOR]

Fazio, C, Elder, CL, and Harris, MM. Efficacy of alternative forms of creatine supplementation on improving performance and body composition in healthy subjects: a systematic review. J Strength Cond Res 36(9): 2663–2670, 2022—Novel forms of creatine have appeared in the marketplace with substantial claims of improved efficacy compared to creatine monohydrate (CrM). The purpose of this study was to conduct a systematic review on alternative forms of creatine to determine (a) whether they are effective ergogenic aids and (b) whether they outperform CrM. A separate comparison was conducted to determine average cost of various forms of creatine. Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Medline, and Google Scholar were systematically reviewed according to PRISMA guidelines. The design of the review was set to answer the PICOS model (subjects, interventions, comparators, outcomes, and study design). Seventeen randomized placebo controlled clinical trials examining exercise performance outcomes and body composition were included in the analysis. Magnesium-creatine chelate and creatine citrate, malate, ethyl ester, nitrate, and pyruvate were the only forms researched in the literature. Of these studies, only 3 studies compared the alternative creatine form to CrM, making it difficult to compare efficacy to CrM. There were no consistent findings of performance enhancement among alternative forms of creatine when compared to placebo. A review of the marketplace shows that CrM is the lowest cost form of creatine. Due to the paucity of studies on alternative forms of creatine as well as high prices on the market of these alternative forms, CrM remains as the most extensively studied form of creatine that shows efficacy, safety, and lowest cost to consumer. [ABSTRACT FROM AUTHOR]

Štefan, L, Kasović, M, and Culej, M. Normative values for health-related physical fitness in first-year police officers. J Strength Cond Res 36(9): 2530–2535, 2022—The main aim of the study was to develop normative values for health-related physical fitness tests in first-year police officers. In this cross-sectional study, we recruited 773 police officers aged 19–28 years old (mean age ± SD = 22 ± 3 years, 34% women). Health-related physical fitness included: (a) polygon backwards (agility), (b) standing broad jump (explosive power of lower extremities), (c) sit-and-reach test (flexibility), and (d) 2.4 km run (aerobic capacity). In addition, maximal oxygen uptake (V̇ o 2max) was calculated. Sex- and age-specific centile smoothed curves for the 20th, 40th, 60th, and 80th percentiles using Cole's LMS method were created. The results showed that men performed better in all health-related physical fitness tests (p < 0.001), compared with women. The median values for polygon backwards, standing broad jump, sit-and-reach test, 2.4 km run and V̇ o 2max were 8 seconds, 210, 15 cm, 721 seconds and 49 mlO2·kg−1·min−1 in men and 10 seconds, 165, 10 cm, 915 seconds and 39 mlO2·kg−1·min−1 in women. No significant interaction between age and health-related physical fitness was observed. This study provides sex- and age-specific normative values for health-related physical fitness in police officers. Findings from this study may be used in detecting a group of police officers who have lower levels of physical fitness. Thus, policies aiming to enhance the level of physical fitness could be implemented within the system. [ABSTRACT FROM AUTHOR]

McAllister, MJ, Gonzalez, AE, and Waldman, HS. Impact of time restricted feeding on markers of cardiometabolic health and oxidative stress in resistance-trained firefighters. J Strength Cond Res 36(9): 2515–2522, 2022—Firefighters are often exposed to numerous occupational stressors that cause inflammation, oxidative stress (OS), and elevated risk for developing cardiometabolic disease. Time-restricted feeding (TRF) has been shown to result in favorable changes in markers of inflammation and cardiometabolic health. This study investigated the impact of a 6-week TRF intervention (14:10; fasting:feeding) in resistance-trained firefighters. Blood was analyzed for several markers of inflammation, OS, and cardiometabolic health: insulin, ghrelin, leptin, glucagon, adiponectin, resistin, advanced glycated end products (AGE), advanced oxidation protein products, total nitrite-nitrate levels, tumor necrosis factor-α, interleukin (IL)-6, IL-8, IL-10, as well as glucose and lipid levels. A graded exercise test was also conducted before and after the TRF intervention, and substrate oxidation rates were calculated and compared before and after the intervention. Comparisons pre and post TRF were determined with dependent t -tests. Time-restricted feeding resulted in significant reductions in advanced oxidation protein products (∼31%) and AGEs (∼25%); however, no other changes were found. These findings suggest that TRF may be a nutrition intervention aimed at improving some select markers of cardiometabolic health in firefighters, namely, by the reductions in advanced oxidation protein products and AGEs. [ABSTRACT FROM AUTHOR]

The article discusses the research papers that were presented at the National Strength and Conditioning Association (NSCA) 2014 Annual Meeting that was held on July 10, 2014. Topics discussed include relationship between lower limb stiffness and medial gastrocnemius (MG) tendon stiffness in unilateral hopping, effect of aerobic exercise on oxygen uptake and lower body strength and potential of basketball players.

Keiner, M, Kadlubowski, B, Sander, A, Hartmann, H, and Wirth, K. Effects of 10 months of speed, functional, and traditional strength training on strength, linear sprint, change of direction, and jump performance in trained adolescent soccer players. J Strength Cond Res 36(8): 2236–2246, 2022—The current study aimed to compare the effects of plyometric and sprint vs. functional vs. strength training on linear sprint (LS 20 m), change of direction (COD; i.e., turning right and left), jump (squat jump [SJ]), and maximum strength (1 repetition maximum [1RM] for a squat) performance in elite adolescent soccer players. A longitudinal design was chosen, and 48 elite male youth were recruited. The athletes were divided into 4 groups (a traditional strength training group [STG], a plyometric and sprint training group [PSTG], a functional training group [FTG], and a control group [CG]). The intervention groups trained for 10 months with additional sessions added to their regular soccer training (4–5 sessions per week); the additional training (2 sessions a week [each about 60 minutes]) consisted of plyometric and sprint training, functional training, and traditional strength training for the PSTG, FTG, and STG, respectively. Data were analyzed using analysis of variance with repeated measurements. The effect sizes were calculated using Hedges g. This study showed significantly superior performance increases with traditional strength training compared with sprint and jump training and functional training for maximum strength (compared with all other groups g = 0.98–1.61), SJ (g = 0.52–0.87 compared with FGT and CG; not significantly different from PSTG), COD (direction of rotation right: compared with all other groups g = 1.58–2.12; direction of rotation left: no significant differences), and 20-m LS (compared with all other groups g = 0.86–1.39) performance over time. Traditional strength training is recommended to increase strength and speed-strength variables and should therefore be given high priority in athletic training programs for elite youth soccer players. [ABSTRACT FROM AUTHOR]

Chaouachi, A, Ben Othman, A, Chaouachi, M, Hechmi, A, Farthing, JP, Granacher, U, and Behm, DG. Comparison of cross-education and global training effects in adults and youth after unilateral strength training. J Strength Cond Res 36(8): 2121–2131, 2022—Youth strength training research examining contralateral, homologous (cross-education), and heterologous (global training) effects after unilateral training have provided mixed results and the relationship to adults has not been compared. The objective was to compare adult and youth cross-education and global training effects on dominant and nondominant limb testing. Initially, 15 men and 15 prepubertal boys volunteered for each unilateral chest press (CP), handgrip training, and control groups (n = 89). Individuals trained their dominant limb 3 times per week for 8 weeks and had their dominant and nondominant limbs tested for CP and leg press 1 repetition maximum (1RM), handgrip, knee extension and flexion, and elbow extension and flexion maximum voluntary isometric contractions (MVICs). Adult CP training gains were significantly greater than youth with lower-body testing (p = 0.002–0.06), whereas youth CP training gains exceeded adults with upper-body tests (p = 0.03–0.07). Training specificity was evident with greater CP 1RM increases with CP vs. handgrip training for both youth (p < 0.0001) and adults (p < 0.0001). Handgrip training elicited greater gains in handgrip MVICs compared with other strength tests (p < 0.0001). In conclusion, only contralateral CP 1RM showed a training advantage for unilateral CP over unilateral handgrip training. Adults showed greater gains with lower-body testing, whereas youth showed greater gains with upper-body testing. [ABSTRACT FROM AUTHOR]

Yepes, MM, Feliu, GM, Bishop, C, and Gonzalo-Skok, O. Assessing the reliability and validity of agility testing in team sports: A systematic review. J Strength Cond Res 36(7): 2035–2049, 2022—The aims of this systematic review were to (a) examine the reliability of the reactive agility tests and (b) analyze the discriminatory validity of the agility tests. A literature search was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We explored PubMed, SPORTDiscus, and Cochrane Plus databases looking for articles about agility in team sports. After filtering for article relevance, only 42 studies met the inclusion criteria; 37 of which assessed the reliability of agility tests and 22 assessing their validity. Reliability showed a high intraclass correlation coefficient (ICC) in almost all studies (range 0.79–0.99) with the exception of 2 studies. In addition, other studies also assessed the reliability of decision time (ICC = 0.95), movement time (ICC = 0.92), and decision accuracy (ICC = 0.74–0.93), all of which exhibited acceptable reliability. Furthermore, these data show high discriminatory validity, with higher performance level players being faster than lower performance level players (mean = 6.4%, range = 2.1–25.3%), with a faster decision time (mean = 23.2%, range = 10.2–48.0%) with the exception of 1 study, and better decision accuracy (mean = 9.3%, range = 2.5–21.0%). Thus, it can be concluded that reactive agility tests show good reliability and discriminatory validity. However, most agility tests occur in simple contexts whereby only 2 possible responses are possible. Therefore, future research should consider creating more specific and complex environments that challenge the cognitive process of high-level athletes. [ABSTRACT FROM AUTHOR]

Fernández-Galván, LM, Casado, A, García-Ramos, A, and Haff, GG. Effects of vest and sled resisted sprint training on sprint performance in young soccer players: A systematic review and meta-analysis. J Strength Cond Res 36(7): 2023–2034, 2022—The aim of the meta-analysis was to determine the effect of resisted sprint training (RST) on sprint performance in young (<20 years) soccer players and to analyze whether the training equipment (sled or vest) and magnitude of the resistive load (above or below 20% of body mass [BM]) influences the long-term adaptations in sprint performance. Resisted sprint training reduced the acceleration phase time [standardized mean difference (SMD) = −0.41], with greater reduction in sprint time occurring in response to applying resistance with a vest (SMD = −0.70) when compared with a sled (SMD = −0.27). Similar reductions were determined for resistive loads <20% (SMD = −0.55) and ≥20% of BM (SMD = −0.31). Full sprint time showed a small reduction after RST (SMD = −0.36), regardless of the training equipment (sled: SMD = −0.44; vest: SMD = −0.26) and resistive load (<20% of BM: SMD = −0.40 ≥ 20% of BM: SMD = −0.21). There was a small and nonsignificant reduction in the maximum-velocity phase after RST (SMD = −0.25), which was comparable when the training was performed with vest (SMD = −0.34) or sled (SMD = −0.22). No significant differences in the changes of the acceleration phase time (SMD = 0.05) or full sprint time (SMD = 0.08) were observed between the experimental (sled or vest RST) and control groups (only soccer or unresisted sprint training). In conclusion, RST is effective to improve sprint performance in young soccer players, but the improvements are not superior to unresisted sprint training. [ABSTRACT FROM AUTHOR]

Hosseini Kakhak, SA, Kianigul, M, Haghighi, AH, Nooghabi, MJ, and Scott, BR. Performing soccer-specific training with blood flow restriction enhances physical capacities in youth soccer players. J Strength Cond Res 36(7): 1972–1977, 2022—This study investigated the effect of soccer training with blood flow restriction (BFR) on physical performance in youth athletes. Nineteen semiprofessional soccer players were randomly assigned to either normal soccer training (ST; n = 9) or soccer training with BFR (STBFR; n = 10). Both groups performed identical activities during a 6-week preseason training phase, either with or without lower limb BFR. Training included soccer-specific drills, small-sided games, plyometrics, and continuous running. Before and after the intervention, players were assessed for leg extension strength and endurance, countermovement jump performance, 40-yd sprint time, change-of-direction (COD) ability, aerobic endurance, and soccer-specific endurance (while dribbling a ball). Significantly larger improvements were observed in the STBFR compared with the ST group for tests of muscular endurance (74.8 ± 34.1% vs. 4.0 ± 14.6%), COD (8.1 ± 3.7% vs. 2.8 ± 4.7%), and aerobic (54.1 ± 19.6% vs. 24.7 ± 27.2%) and soccer-specific endurance (58.4 ± 19.6% vs. 22.7 ± 10.2%). Main effects for time were observed for maximal strength, jumping, and sprinting performance (p < 0.001) but with no group and time interaction. These findings demonstrate that team sport training with BFR can enhance physical qualities that are related to performance in youth soccer players. This application of BFR may improve the adaptive responses of muscles, without having to dedicate additional training time to muscular qualities. [ABSTRACT FROM AUTHOR]

Douglas, AS, Rotondi, MA, Baker, J, Jamnik, VK, and Macpherson, AK. A comparison of on-ice external load measures between subelite and elite female ice hockey players. J Strength Cond Res 36(7): 1978–1983, 2022—This study quantified and examined differences in measures of on-ice external load for subelite and elite female ice hockey players. External load variables were collected from subelite (N = 21) and elite (N = 24) athletes using Catapult S5 monitors during the preseason. A total of 574 data files were analyzed from training and competition during the training camp. Significant differences between groups were found across all variables. Differences in training between the 2 groups ranged from trivial (forwards PlayerLoad, p = 0.03, effect-size [ES] = 0.18) to large (forwards Explosive Efforts [EEs], p < 0.001, ES = 1.64; defense EEs, p < 0.001, ES = 1.40). Match comparisons yielded similar results, with differences ranging from small (defense Low Skating Load [SL], p = 0.05, ES = 0.49; Medium SL, p = 0.04, ES = 0.52) to very large (forwards PlayerLoad, p < 0.001. ES = 2.25; PlayerLoad·min−1, p < 0.001, ES = 2.66; EEs, p < 0.001, ES = 2.03; Medium SL, p < 0.001, ES = 2.31; SL·min−1, p < 0.001, ES = 2.67), respectively. The differences in external load measures of intensity demonstrate the need to alter training programs of subelite ice athletes to ensure they can meet the demands of elite ice hockey. As athletes advance along the development pathway, considerable focus of their off-ice training should be to improve qualities that enhance their ability to perform high-intensity on-ice movements. [ABSTRACT FROM AUTHOR]

Supplemental Digital Content is Available in the Text. Leech RD, Grunseit A, and Edwards KL. Self-report and contemporaneously recorded running agreement in recreational athletes. J Strength Cond Res 36(7): 1922–1929, 2022—Accurate assessment of running exposure in research or clinical practice relies on the ability to measure the behavior validly and reliably. Self-reported physical activity (PA) (including running), although commonly used, is subject to bias. User-owned wearable technological devices provide a potential contemporaneously collected data source for validating retrospective running-specific questionnaires. This study assesses agreement between self-reported running and contemporaneously collected running data. Self-reported running and corresponding contemporaneously recorded for current (at the time of questionnaire completion) and historical (6 months prior) was collected. Concordance Correlations and Bland-Altman Limits of Agreement measured extent of agreement. Categories for Metabolic Equivalent Task (MET) hours per week were calculated from total running distance. Unweighted and weighted Kappas were used to compare classification of levels of running by the 2 data sources. Running data were collected from 139 subjects (mean age 51.1 years). Self-report data were higher than contemporaneous data. Average estimated pace from both sources were similar, with high variance in some individuals. Differences of 43.5–57.1% were reported for current mean weekly running distances for 7-day, 4-week, and 12-week running periods. The level of agreement in classification between self-report and contemporaneous running data MET/HR categories was fair (unweighted K = 0.24–0.33) to moderate (weighted K = 0.46–0.63). Compared with contemporaneous running data, runners over-estimate the frequency, distance, and duration of running in self-report. Runners tend to discount nonrunning periods and unusual runs when estimating current and historical "average" running. The opportunities and limitations of different contemporaneous running data collection methods as a PA comparator must be acknowledged. [ABSTRACT FROM AUTHOR]

Sharp, DW, Swain, JC, Boy, TG, Killen, LG, Green, JM, and O'Neal, EK. Effects of 2.4 kg of proximal external loading on 5-km running performance. J Strength Cond Res 36(7): 1833–1838, 2022—Racing weight is a popular topic in the running community. This study examined effects of modest loading via a ∼2.4-kg soft and malleable weighted compression garment on overground running performance. Former and current collegiate cross-country runners (5 women and 6 men) completed 2 outdoor, solo road course runs 7 days apart on a familiar training route. During the first run (CON) subjects ran as closely as possible to their goal pace for a "hard speed day" workout based on predetermined paces according to current training level. During a subsequent run, subjects attempted to match their pace with aid from global positioning system watches and splits verbally announced on the course while wearing the weighted compression garment (LOAD). Metabolic data was later assessed during 5-minute running bouts on a treadmill with CON and LOAD conditions at subject's CON run pace. LOAD was slower (p < 0.01) at the 1.6-km mark (6:03 ± 0:37 vs. 6:13 ± 0:40) and finish (18:29 ± 2:06 vs. 19:15 ± 2:16). There was no differentiation (p > 0.05) between V̇ o 2 (CON 3.47 ± 0.86; LOAD 3.56 ± 0.77 L·min−1) or respiratory exchange ratio (CON 1.05 ± 0.06; LOAD 1.06 ± 0.04) during the 5-minute running economy bouts. There was an inverse (r = −0.42) but nonsignificant (p = 0.22) relationship between percent difference in body mass and percent difference in performance. Metabolic variable differentiation was not detectable at race pace, but 2.4 kg of proximal loading resulted in an approximately 4% acute performance impairment. [ABSTRACT FROM AUTHOR]

Helme, M, Emmonds, S, and Low, C. Is the rear foot elevated split squat unilateral? An investigation into the kinetic and kinematic demands. J Strength Cond Res 36(7): 1781–1787, 2022—The purpose of the study was to determine the unilateral nature of the rear foot elevated split squat (RFESS). Specifically, the production of force by the rear leg was examined to better understand its role, if any, toward successful completion of the exercise. Male volunteers were recruited (n = 26, age = 23.8 ± 4.6 years, body mass = 88.1 ± 10.7 kg, and height = 1.79 ± 0.1 m), who were recreationally trained and engaged in a structured strength and conditioning program, including both bilateral and unilateral exercises, and had at least 2 years supervised training experience. Subjects participated in an incremental 5 repetition maximum protocol after familiarization. Kinetic data were recorded through 2 independent force plates, 1 integral to the floor and the second mounted on top of solid weightlifting blocks. Kinematic data were captured through 3-dimensional motion analysis. A total of 715 repetitions were analyzed, and the mean contribution of the lead foot to total vertical force production was 84.36 ± 3.6%. An almost certainly small positive correlation (rho = 0.25, confidence interval [CI] 0.18–0.33) was found between the percentage of force produced by the lead foot, with increasing exercise intensity. A most likely trivial, nonsignificant correlation (rho = −0.01, CI −0.09 to 0.06) with rear foot force production, representing the mass of the rear leg. Data from this study do not indicate that the rear foot contributes to the kinetic demands of the exercise and therefore suggests that the RFESS is a valid unilateral exercise. [ABSTRACT FROM AUTHOR]

Supplemental Digital Content is Available in the Text. Kassiano, W, Nunes, JP, Costa, B, Ribeiro, AS, Schoenfeld, BJ, and Cyrino, ES. Does varying resistance exercises promote superior muscle hypertrophy and strength gains? A systematic review. J Strength Cond Res 36(6): 1753–1762, 2022—Fitness professionals routinely employ a variety of resistance training exercises in program design as a strategy to enhance muscular adaptations. However, it remains uncertain whether such an approach offers advantages over a fixed-exercise selection. The objective of this review was to review the effects of exercise variation on muscle hypertrophy and strength. A search of the literature was conducted using PubMed/MEDLINE, Scopus, and Web of Science databases. Eight studies were identified as meeting inclusion criteria. The combined total sample of the studies was N = 241, comprising all young men. The methodological quality of included studies was considered "good" and "excellent" based on the Physiotherapy Evidence Database Scale. The available studies indicate that varying exercise selection can influence muscle hypertrophy and strength gains. Some degree of systematic variation seems to enhance regional hypertrophic adaptations and maximize dynamic strength, whereas excessive, random variation may compromise muscular gains. We conclude that exercise variation should be approached systematically with a focus on applied anatomical and biomechanical constructs; on the contrary, employing different exercises that provide a redundant stimulus, as well as excessive rotation of different exercises (i.e., high frequency of change), may actually hinder muscular adaptations. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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

Kristiansen, M, Thomsen, MJ, Nørgaard, J, Aaes, J, Knudsen, D, and Voigt, M. The effect of anodal transcranial direct current stimulation on quadriceps maximal voluntary contraction, corticospinal excitability, and voluntary activation levels. J Strength Cond Res 36(6): 1540–1547, 2022—Anodal transcranial direct current stimulation (a-tDCS) has previously been shown to improve maximal isometric voluntary contraction (MVIC), possibly through an upregulation of corticospinal excitability. Because muscle strength is an essential part of the performance of many sports, any ergogenic effect of a-tDCS on this parameter could potentially increase performance outcomes. The purpose of this study was to investigate the effect of a-tDCS on MVIC, voluntary activation levels (VALs), and corticospinal excitability, assessed by eliciting motor-evoked potentials (MEPs), in untrained subjects. Thirteen subjects completed 2 test sessions in which they received either a-tDCS or sham stimulation for 3 consecutive intervals of 10 minutes, separated by 5-minute breaks. Before and after each stimulation session, transcranial magnetic stimulation was used to elicit MEPs, and femoral nerve stimulation was used to assess VAL by measuring twitch torque during an MVIC test and in a relaxed state. Two-way analyses of variance with statistical significance set at p ≤ 0.05 were used to test for differences. A significant main effect was identified, as the MVIC pre-test (271.2 ± 56.6 Nm) was on average 4.1% higher compared to the post-test (260.6 ± 61.4 Nm) (p = 0.05). No significant differences were found in MEP, MVIC, or VAL as a result of stimulation type or time. In healthy subjects, the potential for improvement in corticospinal excitability may be negligible, which may in turn explain the lack of improvements in MEP, MVIC, and VAL after a-tDCS. The small decrease in MVIC for both conditions and nonsignificant changes in MEP and VAL do not justify the use of a-tDCS in combination with sporting performance in which the intent is to increase maximal isometric strength performance in the quadriceps muscle of healthy subjects. [ABSTRACT FROM AUTHOR]

Martínez-Navarro, I, Montoya-Vieco, A, Collado, E, Hernando, B, Panizo, N, and Hernando, C. Muscle Cramping in the marathon: Dehydration and electrolyte depletion vs. muscle damage. J Strength Cond Res 36(6): 1629–1635, 2022—Our aim was to compare dehydration variables, serum electrolytes, and muscle damage serum markers between runners who suffered exercise-associated muscle cramps (EAMC) and runners who did not suffer EAMC in a road marathon. We were also interested in analyzing race pacing and training background. Nighty-eight marathoners took part in the study. Subjects were subjected to a cardiopulmonary exercise test. Before and after the race, blood and urine samples were collected and body mass (BM) was measured. Immediately after the race EAMC were diagnosed. Eighty-eight runners finished the marathon, and 20 of them developed EAMC (24%) during or immediately after the race. Body mass change, post-race urine specific gravity, and serum sodium and potassium concentrations were not different between crampers and noncrampers. Conversely, runners who suffered EAMC exhibited significantly greater post-race creatine kinase (464.17 ± 220.47 vs. 383.04 ± 253.41 UI/L, p = 0.034) and lactate dehydrogenase (LDH) (362.27 ± 72.10 vs. 307.87 ± 52.42 UI/L, p = 0.002). Twenty-four hours post-race also values of both biomarkers were higher among crampers (CK: 2,438.59 ± 2,625.24 vs. 1,166.66 ± 910.71 UI/L, p = 0.014; LDH: 277.05 ± 89.74 vs. 227.07 ± 37.15 UI/L, p = 0.021). The difference in the percentage of runners who included strength conditioning in their race training approached statistical significance (EAMC: 25%, non-EAMC: 47.6%; p = 0.074). Eventually, relative speed between crampers and noncrampers only differed from the 25th km onward (p < 0.05). Therefore, runners who suffered EAMC did not exhibit a greater degree of dehydration and electrolyte depletion after the marathon but displayed significantly higher concentrations of muscle damage biomarkers. [ABSTRACT FROM AUTHOR]

The article presents information on a research paper which discusses a technical-didactic program, developed by a water polo coach for players to help them in talent development. It used an individual discriminant analysis to identify improvements in players who were divided in two subgroups, one with higher learning rates and the other with lower learning rates.