Changes in Hip Isometric Strength of Female College Soccer Players After High-Workload Training Session.

CONTEXT: The hip adductor and abductor muscles play vital roles as stabilizers in the lower-extremity. Their activation during soccer-specific actions is essential, but local muscular fatigue can hinder athletic performance and increase the risk of injury. DESIGN: This study aimed to observe the variations in frontal plane hip strength in female college soccer players before and after a high-workload soccer-specific training session. Furthermore, the study sought to compare the relative changes in hip strength with the internal and external load measures obtained during that session. METHODS: Twenty female college soccer players participated in a retrospective observational study. Isometric hip adductor and abductor strength were measured before and after a training session in the college spring season. Measurements were taken with a handheld dynamometer (MicroFET 2) while the players were supine. Global positioning system sensors (Catapult Vector S7), commonly worn by players during training sessions and competitive matches, were used to measure external and internal loads. Statistical analyses were performed using paired samples t test to assess hip adductor and abductor strength changes before and after the training session. Spearman rank was used to identify correlation coefficients between global positioning system data and isometric hip strength. RESULTS: The findings revealed significant decreases in the strength of the right hip adduction (P = .012, -7% relative change), right abduction (P = .009, -7.6% relative change), and left abduction (P = .016, -4.9% relative change) after the training session. Furthermore, relative decreases in hip isometric adduction and abduction strength are related to the distance covered at high speeds. CONCLUSION: The results of this study highlight that hip isometric adduction and abduction strength tend to decrease after exposure to high workloads during soccer-specific training.

A single dose multi-ingredient pre-workout supplement enhances upper body resistance exercise performance.

Introduction: Multi-ingredient pre-workout supplements (MIPS) are commonly used by individuals looking to enhance exercise performance and augment adaptations to training. However, the efficacy of commercially available MIPS is largely dependent on the ingredient profile, and new formulations should be investigated to determine their effectiveness. Therefore, the purpose of this study was to examine the effects of a commercially available MIPS product on performance during an upper body resistance exercise protocol. Methods: Twenty resistance-trained participants (10 men, 10 women) volunteered to complete this double-blind, placebo-controlled, crossover study consisting of 3 visits. Visit 1 consisted of body composition, 1-repetition maximum (1RM) testing, and familiarization. Visits 2 and 3 consisted of supplementation with either MIPS or placebo (PLA) 1 h prior to completion of an upper body resistance exercise workout during which power output, repetitions completed, rating of perceived exertion (RPE), and perceived recovery were recorded. Assessments of reaction time, isometric mid-thigh pull, and perceived levels of focus, energy, fatigue, and "muscle pump" were also completed before supplementation, 1 h after supplementation, and immediately after exercise. Results: Statistical analysis revealed significant main effects of trial for reaction time (p < 0.001) and bench press peak power (p = 0.026) indicating better performance during the MIPS trial. Furthermore, total number of repetitions completed significantly increased (p = 0.003) during the MIPS (96.90 ± 21.31 repetitions) trial compared to PLA (89.50 ± 18.37 repetitions). Additionally, overall session RPE was significantly lower (p = 0.002) during the MIPS (7.6 ± 1.2) trial compared to PLA (8.3 ± 0.9). Discussion: These findings suggest that acute supplementation with this MIPS improved upper body resistance exercise performance while reducing participant RPE. Further research should investigate the efficacy of chronic supplementation with this MIPS as the acute response provided an ergogenic benefit.

Utility of Novel Rotational Load-Velocity Profiling Methods in Collegiate Softball Players.

ABSTRACT: Herring, CH, Beyer, KS, Redd, MJ, Stout, JR, and Fukuda, DH. Utility of novel rotational load-velocity profiling methods in collegiate softball players. J Strength Cond Res 38(1): 136-145, 2024-The purpose of this study was to determine the reliability of bat swing (BS) and rotational medicine ball throw (RMBT) load-velocity profiling (LVP) methods and explore relationships with batting performance in NCAA Division I softball players. Bat velocity was tracked with a swing sensor during the BS method, whereas an inertial measurement unit (IMU) tracked forearm velocity during the BS and RMBT methods. Intraclass correlation coefficients (ICC) were used for relative reliability, and coefficient of variation (CV) was used for absolute reliability. With the exception of theoretical maximum velocity (V0) using the average of top 2 peak velocities (PVavg) during the RMBT, no LVP variables were found to be reliable during the RMBT or BS method using the IMU (ICC ≤0.7; CV ≥15%). For the BS method with the swing sensor, all bat loads and V0 had acceptable reliability using peak velocity (PV) and PVavg (ICC >0.7; CV <15%), whereas all LVP variables were highly related between the multiple-load and two-load models when using PV and PVavg (r = 0.915-0.988; p < 0.01). There were significant relationships (r = 0.603-0.671; p < 0.05) between PV using the 0.99 Kg bat load and V0, and several in-game batting statistics. Practitioners may use the BS with the swing sensor as a rotational LVP assessment, although they should be cautious of aiming to improve batting performance in collegiate softball players based on the correlations reported until further research is performed.

Effect of Test Sequence on Maximal Anaerobic and Aerobic Power Achievements in Adults.

The purpose of this study was to examine the effect of test sequence on adults' ability to achieve maximal aerobic and anaerobic power during a single assessment visit. Forty-one adults (24 men, 17 women; 22.0 ± 1.8 years) completed two baseline visits in randomized order consisting of either a maximal oxygen consumption (V̇O2max) or Wingate anaerobic test (WAnT). The subsequent experimental visit consisted of both V̇O2max and WAnT in randomized order separated by 20 minutes of rest. Mixed-model ANOVAs compared baseline and experimental performance between and within groups. Chi Squared Goodness of Fit tests determined if test sequence significantly affected V̇O2max criteria achievement. Significant interaction effects were observed for relative V̇O2max (p = 0.005), RER (p < 0.001), and exercise time (p = 0.022). Within WAnT/V̇O2max subjects, these values significantly decreased from baseline to experimental tests. No differences were found for WAnT values. During the experimental session, 50% of subjects who performed WAnt/V̇O2max and 81% of subjects who performed V̇O2max/WAnT achieved a valid V̇O2max. Chi squared analysis found the change to be significant in WAnT/V̇O2max subjects only. Therefore, performing the WAnT before V̇O2max sequence significantly reduced the percent of subjects who achieved V̇O2max criteria. These findings indicate that the sequence of V̇O2max testing before a WAnT allowed maximal results similar to expected baseline values.

Relative Age Effects in Elite Olympic Weightlifters.

ABSTRACT: Kollars, JM, Taber, CB, and Beyer, KS. Relative age effects in elite olympic weightlifters. J Strength Cond Res 35(5): 1223-1228, 2021-The time of year in which an athlete is born may provide an advantage developmentally for competition, known as relative age effects (RAEs). The presence of RAEs in sport may result in athletes participating less or leaving the sport early. To determine if RAEs exist in elite Olympic weightlifting, data were examined from the past 5 Olympic Games. Using retrospective competition data, a total of 953 weightlifters (595 men and 358 women) who competed in the Olympic Games between 2000 and 2016 were included in this study. Athletes were divided into lightweight, middleweight, and heavyweight for analysis. Using the subset weight classes, the observed date of birth distribution vs. the expected worldwide date of birth distribution were compared using multiple chi square tests. Relative age effects were present overall for weightlifters (χ2 = 189.428, p < 0.001), with over-representation in January (z = +12.6, 20.9%) and under-representation in June (z = -2.1, 6.3%), September (z = -3.2, 5.7%), and November (z = -3.0, 5.1%). Relative age effects were also present in men lightweight (χ2 = 74.773, p < 0.001), men middleweight (χ2 = 41.786, p < 0.001), men heavyweight (χ2 = 39.395, p < 0.001), and women lightweight (χ2 = 37.251, p < 0.001). Determining that RAEs are present in weightlifting is important because it will help maintain the amount of opportunity for all athletes regardless of when they were born in the year. Coaches should be aware of the possible advantages of training age and the effect of physical maturation as a result of these RAEs. Coaches may use this information for athlete selection, but the presence of RAEs should not discourage athletes from participating in the sport of weightlifting.

Relative Age Effects as Evidence of Selection Bias in Major League Baseball Draftees (2013-2018).

ABSTRACT: Herring, CH, Beyer, KS, and Fukuda, DH. Relative age effects as evidence of selection bias in major league baseball draftees (2013-2018). J Strength Cond Res 35(3): 644-651, 2021-The purpose of this study was to examine if relative age effects (RAEs) or the unequal birth-date distribution among a cohort group of individuals exist in Major League Baseball (MLB) draftees. This study comprised 7,078 men drafted in the MLB first-year player draft from 2013 to 2018. Data collected for each draftee included birth date, year drafted, academic-level classification, position, round drafted, batting side, and throwing arm. Draftee's birth dates were categorized into quarters based on the calendar year for baseball in the United States (Q1: August-October; Q2: November-January; Q3: February-April; Q4: May-July). Player birth-date distributions were compared with average expected birth-date distributions and evaluated with the χ2 goodness of fit statistic. Significant χ2 tests were followed up by calculating the standardized residual for each quarter. Differences from the expected frequencies were found for the overall group (p < 0.001) with standardized residuals for baseball athletes born in Q1 (z = +4.45) and Q3 (z = -4.15) exceeding ±2.0. Similar patterns were noted for high schoolers (Q1: z = +3.30; Q3: z = -3.28), pitchers (Q1: z = +2.78; Q3: z = -3.12), early middle rounders (Q1: z = +3.08; Q3: z = -2.67), late rounders (Q1: z = +2.70; Q3: z = -2.61), right-side hitters (Q1: z = +3.23; Q3: z = -2.26), left-handed pitchers (Q1: z = + 2.12; Q3: z = -2.59), and right-handed positional players (Q1: z = +3.12; Q3: z = -2.12). Consistent with the majority of previous research, RAEs are apparent in MLB draftees, with specific patterns of unequal distribution among subsets of athletes.

Effect of somatic maturity on the aerobic and anaerobic adaptations to sprint interval training.

The purpose of this study was to assess the maturity-related differences in the aerobic and anaerobic adaptations to sprint interval training (SIT) among youth male athletes. Twenty-seven youth male athletes were assessed for years from peak height velocity (PHV) and classified into prepubescent (PRE, n = 7, years from PHV = -2.21 ± 0.47 years), peripubescent (PERI, n = 10, years from PHV = 0.25 ± 0.88 years), and postpubescent (POST, n = 10, years from PHV = 2.81 ± 0.50 years) groups based on their years from estimated peak height velocity. Participants completed a ramp exercise protocol on a cycle ergometer to determine maximal aerobic power, maximal oxygen consumption (VO2peak ), and fatigue thresholds. Following baseline, all participants completed a 4-week SIT program that consisted of eight total training sessions. During each session, participants completed repeated 20-s sprints on a cycle ergometer against a resistance of 7.5% of body mass. The number of sprints per sessions increased from four in session 1 to seven in session 7, with four sprints in session 8. Peak and mean power from sessions 1 and 8 were recorded. All participants completed a post-testing ramp exercise protocol that mirrored baseline. Maximal aerobic power increased (p < .001) across all groups from baseline (212.61 ± 57.45 W) to post-testing (223.24 ± 58.90 W); however, VO2peak only increased in POST (3.31 ± 0.43 to 3.54 ± 0.43 L min-1 , p = .003). Similarly, GET, VT, and RCP increased in POST, with no changes in PRE or PERI. In terms of anaerobic performance, PERI and POST had significant increases in peak and mean power. POST improved aerobic and anaerobic performance following SIT, while PERI only experienced improvements in anaerobic performance. Conversely, PRE had no changes in aerobic or anaerobic performance. The adaptations to SIT appear to be influenced by the somatic maturity status.

Relative Age Effect in Collegiate Soccer: Influence of Nationality, Playing Position, and Class.

Hurley, E, Comstock, BA, Haile, L, and Beyer, KS. Relative age effect in collegiate soccer: influence of nationality, playing position, and class. J Strength Cond Res 33(12): 3295-3301, 2019-The purpose of this study was to evaluate the existence of relative age effects (RAEs) in collegiate soccer. In addition, the impact of nationality, position, class, and National Collegiate Athletic Association (NCAA) tournament qualification status on the prevalence of RAEs was assessed. Birth dates from male NCAA Division I soccer athletes (n = 4,082) from the 2017/2018 season were categorized into quarters based on calendar and scholastic quarters. All athlete birth-date distributions were compared with the expected birth-date distributions for the United States. International-born athletes (INT) displayed a significant difference in birth-date distribution when assessed with calendar quarters, whereas American-born athletes (USA) showed a significant difference in birth-date distributions when assessed with scholastic quarters. Furthermore, INT showed significant RAEs for midfielders and defenders, whereas USA showed significant RAEs midfielders and goalkeepers. In terms of class, INT had significant RAEs for all classes, whereas USA had significant RAEs only for freshmen and sophomores. All INT had significant RAEs regardless of tournament qualification status; however, USA had significant RAEs only for nontournament teams. In summary, significant RAEs exist in male Division I college soccer; however, the presence of RAEs is influenced by nationality, position, class, and NCAA tournament qualification status. Coaches should be aware of RAEs during the recruitment process to avoid potential selection bias.

Maturity-Related Differences in Systemic Pulmonary and Localized Fatigue Threshold Among Youth Male Athletes.

PURPOSE: To examine the reliability and the maturity-related differences of fatigue thresholds (FTs) among youth males. METHODS: Twenty-nine youth males (11-17 y) completed 2 ramp exercise tests on a cycle ergometer. Systemic FTs were calculated from gas exchange and ventilation variables. Localized FTs were calculated from electromyography and near-infrared spectroscopy of the vastus lateralis. All FTs were determined using the maximal distance method and expressed relative to maximal oxygen consumption. All participants were grouped according to the number of years from peak height velocity into PRE- (< -1.5 y), PERI- (-1.5 to +1.5 y) and POST- (> +1.5 y) peak height velocity. Reliability was assessed with intraclass correlation coefficients, and differences between groups were assessed with analysis of variance and Cohen's d coefficients. RESULTS: Analysis of variance revealed significant group differences with PRE having significantly greater systemic pulmonary FTs than POST, while localized muscular FTs were significantly greater in PRE when compared with PERI and POST. All FTs exhibited excellent reliability (intraclass correlation coefficient > .75) in all maturity groups. CONCLUSION: Maturity status appears to influence the onset of FTs among youth male athletes, with FTs occurring later in younger athletes. Furthermore, all FTs were reliable measures regardless of maturity.

Resistance training does not induce uniform adaptations to quadriceps.

Resistance training may differentially affect morphological adaptations along the length of uni-articular and bi-articular muscles. The purpose of this study was to compare changes in muscle morphology along the length of the rectus femoris (RF) and vastus lateralis (VL) in response to resistance training. Following a 2-wk preparatory phase, 15 resistance-trained men (24.0 ± 3.0 y, 90.0 ± 13.8 kg, 174.9 ± 20.7 cm) completed pre-training (PRE) assessments of muscle thickness (MT), pennation angle (PA), cross-sectional area (CSA), and echo-intensity in the RF and VL at 30, 50, and 70% of each muscle's length; fascicle length (FL) was estimated from respective measurements of MT and PA within each muscle and region. Participants then began a high intensity, low volume (4 x 3-5 repetitions, 3min rest) lower-body resistance training program, and repeated all PRE-assessments after 8 weeks (2 d ∙ wk-1) of training (POST). Although three-way (muscle [RF, VL] x region [30, 50, 70%] x time [PRE, POST]) repeated measures analysis of variance did not reveal significant interactions for any assessment of morphology, significant simple (muscle x time) effects were observed for CSA (p = 0.002) and FL (p = 0.016). Specifically, average CSA changes favored the VL (2.96 ± 0.69 cm2, p < 0.001) over the RF (0.59 ± 0.20 cm2, p = 0.011), while significant decreases in average FL were noted for the RF (-1.03 ± 0.30 cm, p = 0.004) but not the VL (-0.05 ± 0.36 cm, p = 0.901). No other significant differences were observed. The findings of this study demonstrate the occurrence of non-homogenous adaptations in RF and VL muscle size and architecture following 8 weeks of high-intensity resistance training in resistance-trained men. However, training does not appear to influence region-specific adaptations in either muscle.

Resistance Exercise Selectively Mobilizes Monocyte Subsets: Role of Polyphenols.

PURPOSE: To examine the impact of polyphenol supplementation on the recruitment, mobilization, and activation of monocyte subsets after resistance exercise. METHODS: Thirty-eight recreationally active males (22.1 ± 3.1 yr; 173.9 ± 7.9 cm; 77.8 ± 14.5 kg) were assigned to 28 d of polyphenol blend (PPB) supplementation, placebo (PL), or control (CON). Blood samples were obtained before (PRE) postresistance exercise, immediately (IP) postresistance exercise, 1 h (1H) postresistance exercise, 5 h (5H) postresistance exercise, 24 h (24H) postresistance exercise, and 48 h (48H) postresistance exercise (PPB/PL) or rest (CON). Fine-needle biopsies were obtained from the vastus lateralis at PRE, 1H, 5H, and 48H. Circulating concentrations of macrophage chemoattractant protein-1 (MCP-1) and fractalkine, as well as intramuscular MCP-1 were analyzed via multiplex assay. Changes in the proportions and expression of CD11b on monocyte subsets were assessed via flow cytometry. RESULTS: Circulating MCP-1 increased in PPB and PL at IP with further increases at 5H. Intramuscular MCP-1 was increased at 1H, 5H, and 48H in all groups. Classical monocyte proportions were reduced in PPB and PL at IP, and increased at 1H. Nonclassical monocytes were increased in PPB and PL at IP, whereas intermediate monocytes were increased at IP, and reduced at 1H. Intermediate monocytes were increased in PPB at 24H and 48H. CD11b expression was reduced on PPB compared with PL and CON at PRE on intermediate and nonclassical monocytes. CONCLUSIONS: Resistance exercise may elicit selective mobilization of intermediate monocytes at 24H and 48H, which may be mediated by tissue damage. Additionally, polyphenol supplementation may suppress CD11b expression on monocyte subsets at rest.

Influence of Baseline Muscle Strength and Size Measures on Training Adaptations in Resistance-trained Men.

The influence of baseline strength or muscle size on adaptations to training is not well-understood. Comparisons between novice and advanced lifters, and between stronger and weaker experienced-lifters, have produced conflicting results. This study examined the effect of baseline muscle strength and size on subsequent adaptations in resistance-trained individuals following a traditional high-volume, short-rest resistance training protocol. Fourteen resistance-trained men (24.0±2.7 y; 90.1±11.7 kg; 169.9±29.0 cm) completed pre-training (PRE) ultrasound measurements of muscle cross-sectional area (CSA) in the rectus femoris (RF), vastus lateralis (VL), pectoralis major, and triceps brachii (TRI) prior to strength assessments (e.g., one-repetition maximum strength bench press and back-squat). Post-training (POST) assessments were completed following 8-wks (4 d·wk-1) of resistance training. Comparisons were made between stronger (STR) and weaker (WKR) participants, and between larger (LGR) and smaller (SMR) participants, based upon PRE-muscle strength and size, respectively. When groups were based on upper-body strength, repeated measures analysis of variance indicated a significant group × time interaction where greater improvements in bench press strength were observed in WKR (12.5±8.6%, p = 0.013) compared to STR (1.3±5.4%, p=0.546). Within this comparison, STR also possessed more resistance training experience than WKR (mean difference=3.1 y, p=0.002). No other differences in experience or adaptations to training were observed. These data suggest that following a short-duration training program (8-weeks), baseline size and strength have little impact on performance gains in resistance-trained individuals who possess similar years of experience. However, when training experience is different, baseline strength may affect adaptations.

No Observable Relative Age Effects in Professional Surfers: a Constraints-Based Evaluation.

With the recent inclusion of surfing in the 2020 Olympic Games in Japan, there will be a number of surfing athletes vying for one of the twenty total available spots for their respective gender. The purpose was to evaluate relative age effects (RAEs) in surfing with consideration for specific developmental constraints. Elite competitive male surfers (n = 1590) were examined by birth month and subcategorized by competitive level, age groups, and geographical regions. The observed quarterly distribution was not significantly different (using χ2; p>0.05) from expected for the overall group or any of the subcategories. However, an odds ratio of 1.85 (90% confidence interval: 1.08-3.14) was calculated for being born in the first semester of the year compared to being born in the second semester between top 34 athletes and the rest of the field. Despite consideration for individual, environmental, and task constraints in this study, the sport of surfing does not appear to have any observable RAEs at the professional level. Thus, surfing appears to be one of the few sporting activities included in the Olympic Programme with limited RAEs.

Polyphenol supplementation alters intramuscular apoptotic signaling following acute resistance exercise.

The purpose of this study was to examine the effects of 28-days of supplementation with an aqueous proprietary polyphenol blend (PPB) sourced from Camellia sinensis on intramuscular apoptotic signaling following an acute lower-body resistance exercise protocol and subsequent recovery. Untrained males (n = 38, 21.8 ± 2.7 years, 173.4 ± 7.9 cm, 77.6 ± 14.6 kg) were randomized to PPB (n = 14), placebo (PL; n = 14) or control (CON; n = 10). Participants completed a lower-body resistance exercise protocol comprised of the squat, leg press, and leg extension exercises. Skeletal muscle microbiopsies were obtained from the vastus lateralis preexercise (PRE), 1-h (1HR), 5-h (5HR), and 48-h (48HR) post-resistance exercise. Apoptotic signaling pathways were quantified using multiplex signaling assay kits to quantify total proteins (Caspase 3, 8, 9) and markers of phosphorylation status (JNK, FADD, p53, BAD, Bcl-2). Changes in markers of muscle damage and intramuscular signaling were analyzed via separate repeated measures analysis of variance (ANOVA). Change in Bcl-2 phosphorylation at 1H was significantly greater in PL compared to CON (P = 0.001). BAD phosphorylation was significantly elevated at 5H in PL compared to PPB (P = 0.015) and CON (P = 0.006). The change in JNK phosphorylation was significantly greater in PPB (P = 0.009), and PL (P = 0.017) compared to CON at 1H, while the change for PL was elevated compared to CON at 5H (P = 0.002). A main effect was observed (P < 0.05) at 1H, 5H, and 48H for p53 and Caspase 8, with Caspase 3 and Caspase 9 elevated at 48H. These data indicate that chronic supplementation with PPB alters apoptotic signaling in skeletal muscle following acute muscle-damaging resistance exercise.

Effects of supine rest duration on ultrasound measures of the vastus lateralis.

INTRODUCTION: Due to the potential for intramuscular fluid shifts from changing body position, researchers often utilize a 10- to 15-min period of supine rest as a standardizing procedure prior to ultrasound assessment of the lower limbs. However, no previous research has observed the changes in muscle morphological characteristics via ultrasonography of the lower limbs depending on the length of time of supine rest to determine whether 10-15 min of supine rest is necessary. The aim of this study was to examine changes in muscle morphology of the vastus lateralis (VL) at various time-points over the course of 15 min of supine rest. METHODS: Muscle thickness (MT), cross-sectional area (CSA) and echo intensity (EI) of the VL were assessed in 24 adults at four time-points including the following: immediately upon moving from a standing to supine position (T0), after 5 (T5), 10 (T10) and 15 min (T15) of lying in a supine position. RESULTS: CSA significantly decreased from T0 to T10 (P = 0·001) and T15 (P<0·001), with no difference between any other time-points (P = 0·055-0·666). However, the reported changes in CSA did not exceed the standard error of the measurement for this procedure. No significant differences between any time-points for MT (P = 0·726-0·966) or EI (P = 0·061-0·783) were observed. DISCUSSION: These findings suggest extended periods of supine rest may not be needed to obtain consistent muscle morphological measurements of the VL using ultrasonography.

Impact of Polyphenol Supplementation on Acute and Chronic Response to Resistance Training.

Beyer, KS, Stout, JR, Fukuda, DH, Jajtner, AR, Townsend, JR, Church, DD, Wang, R, Riffe, JJ, Muddle, TWD, Herrlinger, KA, and Hoffman, JR. Impact of polyphenol supplementation on acute and chronic response to resistance training. J Strength Cond Res 31(11): 2945-2954, 2017-This study investigated the effect of a proprietary polyphenol blend (PPB) on acute and chronic adaptations to resistance exercise. Forty untrained men were assigned to control, PPB, or placebo. Participants in PPB or placebo groups completed a 4-week supplementation period (phase I), an acute high-volume exercise bout (phase II), and a 6-week resistance training program (phase III); whereas control completed only testing during phase II. Blood draws were completed during phases I and II. Maximal strength in squat, leg press, and leg extension were assessed before and after phase III. The exercise protocol during phase II consisted of squat, leg press, and leg extension exercises using 70% of the participant's strength. The resistance training program consisted of full-body exercises performed 3 d·wk. After phase I, PPB (1.56 ± 0.48 mM) had greater total antioxidant capacity than placebo (1.00 ± 0.90 mM). Changes in strength from phase III were similar between PPB and placebo. Polyphenol blend supplementation may be an effective strategy to increase antioxidant capacity without limiting strength gains from training.

Comparison of Two ß-Alanine Dosing Protocols on Muscle Carnosine Elevations.

OBJECTIVE: ß-alanine (BA) is a nonproteogenic amino acid that combines with histidine to form carnosine. The amount taken orally in individual doses, however, is limited due to symptoms of paresthesia that are associated with higher doses. The use of a sustained-release formulation has been reported to reduce the symptoms of paresthesia, suggesting that a greater daily dose may be possible. The purpose of the present study was to determine whether increasing the daily dose of BA can result in a similar increase in muscle carnosine in a reduced time. METHODS: Eighteen men and twelve women were randomized into either a placebo (PLC), 6-g BA (6G), or 12-g BA (12G) groups. PLC and 6G were supplemented for 4 weeks, while 12G was supplemented for 2 weeks. A resting blood draw and muscle biopsy were obtained prior to (PRE) and following (POST) supplementation. Plasma and muscle metabolites were measured by high-performance liquid chromatography. The loss in peak torque (ΔPT) was calculated from maximal isometric contractions before and after 250 isokinetic kicks at 180°·sec-1 PRE and POST. RESULTS: Both 12G (p = 0.026) and 6G (p = 0.004) increased muscle carnosine compared to PLC. Plasma histidine was decreased from PRE to POST in 12G compared to PLC (p = 0.002) and 6G (p = 0.001), but no group x time interaction (p = 0.662) was observed for muscle histidine. No differences were observed for any hematological measure (e.g., complete blood counts) or in symptoms of paresthesia among the groups. Although no interaction was noted in ΔPT, a trend (p = 0.073) was observed. CONCLUSION: Results of this investigation indicate that a BA supplementation protocol of 12 g/d-1, using a sustained-release formulation, can accelerate the increase in carnosine content in skeletal muscle while attenuating paresthesia.

Mathematical Modeling and Expression of Heart Rate Deflection Point using Heart Rate and Oxygen Consumption.

Heart rate deflection point (HRDP) can be determined through different mathematical-modeling procedures, such as bi-segmental linear regression (2SEG) or maximal distance model (Dmax). The purpose was to compare heart rate (HR) and oxygen consumption (VO2) at HRDP when using 2SEG and Dmax, and to examine their relationships with respiratory compensation point (RCP) and running performance. Nineteen participants completed a graded exercise test (GXT), to determine HRDP and RCP, and a 5km treadmill time trial (5Ktime). No differences were found in HR or VO2 when comparing HRDP2SEG, HRDPDmax, and RCP. Strong correlations were found between HRDP2SEG, HRDPDmax, and RCP when using HR and VO2. No relationships were found between 5Ktime and HR at HRDP or RCP; however, strong relationships were found with VO2. While 2SEG and Dmax may be interchangeable in determining HRDP, VO2 at HRDP and RCP yielded stronger relationships to 5Ktime than HR. Therefore, VO2 at HRDP may be a better predictor of running performance than HR.

Post-resistance exercise ingestion of milk protein attenuates plasma TNFα and TNFr1 expression on monocyte subpopulations.

Attenuating TNFα/TNFr1 signaling in monocytes has been proposed as a means of mitigating inflammation. The purpose of this study was to examine the effects of a milk protein supplement on TNFα and monocyte TNFr1 expression. Ten resistance-trained men (24.7 ± 3.4 years; 90.1 ± 11.3 kg; 176.0 ± 4.9 cm) ingested supplement (SUPP) or placebo (PL) immediately post-exercise in a randomized, cross-over design. Blood samples were obtained at baseline (BL), immediately (IP), 30-min (30P), 1-h (1H), 2-h (2H), and 5-h (5H) post-exercise to assess plasma concentrations of myoglobin; tumor necrosis factor-alpha (TNFα); and expression of tumor necrosis factor receptor 1 (TNFr1) on classical, intermediate, and non-classical monocytes. Magnitude-based inferences were used to provide inferences on the true effects of SUPP compared to PL. Plasma TNFα concentrations were "likely attenuated" (91.6% likelihood effect) from BL to 30P in the SUPP group compared with PL (d = 0.87; mean effect: 2.3 ± 2.4 pg mL-1). TNFr1 expressions on classical (75.9% likelihood effect) and intermediate (93.0% likelihood effect) monocytes were "likely attenuated" from BL to 2H in the SUPP group compared with PL (d = 0.67; mean effect: 510 ± 670 RFU, and d = 1.05; mean effect: 2500 ± 2300 RFU, respectively). TNFr1 expression on non-classical monocytes was "likely attenuated" (77.6% likelihood effect) from BL to 1H in the SUPP group compared with PL (d = 0.69; mean effect: 330 ± 430 RFU). Ingestion of a milk protein supplement immediately post-exercise appears to attenuate both plasma TNFα concentrations and TNFr1 expression on monocyte subpopulations in resistance-trained men.

Comparison of the recovery response from high-intensity and high-volume resistance exercise in trained men.

PURPOSE: The purpose of this study was to compare the physiological responses of a high-volume (HV; 8 sets of 10 repetitions) versus high-intensity (HI; 8 sets of 3 repetitions) exercise protocol in resistance-trained men. METHODS: Twelve men (24.5 ± 4.2 years; 82.3 ± 8.4 kg; 175.2 ± 5.5 cm) with 6.3 ± 3.4 years of resistance training experience performed each protocol in a counterbalanced, randomized order. Performance [counter movement jump peak power (CMJP), isokinetic (ISOK) and isometric leg extension (MVIC), isometric mid-thigh pull (IMTP), and isometric squat (ISQ)] and muscle morphological [cross-sectional area (CSA) of vastus lateralis] assessments were performed at baseline (BL), 30-min (P-30 min), 24-h (P-24 h), 48-h (P-48 h), and 72-h (P-72 h) post-exercise for each testing session. In addition, endocrine (testosterone and cortisol), inflammatory [interleukin-6 (IL-6) and C-reactive protein (CRP)], and markers of muscle damage [creatine kinase (CK), lactate dehydrogenase (LDH), and myoglobin (Mb)] were assessed at the same time points. RESULTS: Significantly greater reductions in CMJP (p < 0.001), and peak torque during both ISOK (p = 0.003) and MVIC (p = 0.008) at P-30 min were detected in HV compared to HI protocol. MVIC was still impaired at P-72 h following the HV protocol, while no differences were noted following HI. Markers of muscle damage (LDH, CK, and Mb) were significantly elevated following both HV and HI (p < 0.05), while cortisol and IL-6 concentrations were significantly elevated at P-30 min following HV only (p < 0.001 and p < 0.05, respectively). CONCLUSIONS: Results indicate that high-volume resistance exercise results in greater performance deficits, and a greater extent of muscle damage, than a bout of high-intensity resistance exercise.