Previous research has investigated the use of music as an ergogenic aid for exercise performance; however, the effect of music on exercise may differ between individuals of varying levels of mental toughness (MT). Purpose: The purpose of this study is to examine the moderating effect of MT on the effect of listening to music during exercise. Methods: The current study used a counter-balanced design, utilizing a mixed-methods approach. Thirty-one recreationally-active individuals (22.13 ± 2.11 yrs, 1.73 ± .10 m, 75.68 ± 14.67 kg, 42.89 ± 5.31 mL·kg·min-1; 65.5% males) were recruited for this study. Participants completed an initial visit to complete a MT questionnaire and create a personalized music playlist of at least 15 songs. Participants completed two familiarization trials and a VO2max test on the treadmill, all on separate days. The experimental trials consisted of two separate conditions: 1) no music (NM); and 2) self-selected music (SSM). For each experimental trial, participants performed a time-to-exhaustion (TTE) run at 80% of their VO2max, separated by at least 48 hours, followed by a post-study interview. Pearson product-moment correlations were used to investigate relationships between performance variables and MT. Moderated regression analysis was used to determine a potential order effect, as well as a potential moderating effect of MT on change in performance between NM and SSM groups. Linear regression analysis was used to determine a potential relationship between MT and change in performance between NM and SSM groups. An alpha level of p ≤ 0.05 was used to determine statistical significance. All qualitative data from post-study interviews was transcribed, coded, and categorized into primary themes. All statistical analyses was conducted via the Statistical Package for Social Science (SPSS) software for Windows version 21 (SPSS Inc., Chicago, IL). Results: Averages were calculated for MT (156.39 ± 9.38), TTE SSM (14.18 ± 4.79 minutes), and TTENM (12.23 ± 5.24 minutes). Correlations were found between VO2max and TTESSM, TTENM, and MT (r = 0.390, p = 0.030; r = 0.519, p = 0.003; r = 0.404, p = 0.024; respectively). Moderated regression analysis revealed a non-significant interaction between MT, music, and order, indicating no order effect (β = -0.416, p = 0.735). Independent samples t-tests revealed no significant difference in MT, performance, or VO2maz between groups of participants who received music first or music second, indicating no effect of order (F = 0.388; p = 0.538; F = 0.537; p = 0.470; F = 0.070; p = 0.794; respectively. Moderated regression analysis, via linear regression, determined no significant moderating effect of MT on the change in performance between trials (ΔTTE) (F (3, 58) = 0.958, r = 0.217, p = 0.498). Linear regression, however, revealed a significant main effect of MT, indicating an inverse relationship between MT and ΔTTE (F (1, 29) = 4.417, r = -0.634, p = 0.044). Discussion: The results from the current study indicate that greater levels of MT were associated with less change between the two performance trials, however, there were no significant relationships between MT or performance with self-selected music. This finding suggests that individuals with greater MT may demonstrate consistent patterns of performance, irrespective of the presence of external factors. Understanding the effects of MT and how external and internal stimuli affect performance may allow exercise professionals to tailor their training or rehabilitation programs to each individual, therefore increasing exercise performance and adherence.

No description available.

No description available.

No description available.

It is a well-documented finding that blood lactate concentrations at any given absolute or relative (% of maximum oxygen uptake; % VO₂ₘₐₓ) workload, are lower following endurance training. The search for the mechanisms responsible for lower blood lactate concentrations after training, however, has led to conflicting results, particularly when the possible causes of this finding have been investigated in humans. In this study, three questions related to the effects of endurance training on lactate metabolism were investigated.

The Army Combat Fitness Test (ACFT) will become the United States Army's mandatory physical fitness test in March 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 was collected in November 2020 (Fall) and March 2021 (Spring) from male (n = 55) and female (n = 17) Army Reserve Officers' Training Corps (ROTC) cadets. Body composition was assessed with a bioelectrical impedance spectroscopy (BIS) device, and cadets completed a squat jump (SJ) force-velocity profile (FVP) and a hex bar deadlift (DL) load-velocity profile (LVP). Stepwise multiple regressions were used to explain the maximal amount of variance in ACFT total score and individual event performance. Results revealed that body composition and lower body power production may have a strong influence on ACFT performance. In terms of accounting for variance in ACFT total score, skeletal muscle mass and body fat percentage were able to account for 49% of shared variance, SJ height (unloaded) and SJ maximal force for 64% of shared variance, and DL maximal power and maximal velocity for 67% of shared variance. The 3-repetition maximum deadlift, standing power throw, hand-release push-up, and sprint-drag-carry events favor cadets with more muscle mass, while the leg tuck is influenced by body fat percentage and the two-mile run is affected by fat mass. Men outperformed women on all individual events and had a higher total ACFT score. Sex had greater predictive capability for the two-mile run than body composition, and for the sprint-drag-carry than any SJ metric. The greatest sex differences were on the standing power throw and sprint-drag-carry. It is recommended that Army ROTC cadets taking the ACFT maximize power production and increase muscle mass.

The purposes of this study were to determine the reliability of the bat swing (BS) and rotational medicine ball throw (RMBT) load-velocity profiling (LVP) methods and the relationships between LVP variables and batting performance in NCAA Division I softball players. Current NCAA Division I softball athletes participated in this study. Bat velocity was tracked with a swing sensor during the BS method. An inertial measurement unit (IMU) tracked forearm velocity during the BS and RMBT methods. Two-way intraclass correlation coefficients (ICC) were used for relative reliability and coefficient of variation (CV) was used for absolute reliability. For the BS method with the swing sensor, relationships between the multiple- and two-load models and between LVP variables and batting variables were examined using Pearson's correlation coefficients. During the RMBT method and BS method using the IMU, no LVP variables were reliable (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 average peak velocity (PVavg) (ICC > 0.7; CV < 15%). All LVP variables were highly related between the multiple- and two-load models when utilizing 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 slugging percentage and on-base plus slugging, and between V0 and doubles, runs batted in, and total bases. Neither the RMBT method nor the BS method using the IMU provided reliable LVP variables. All bat velocities were highly reliable during the BS method using the swing sensor, while only V0 provided acceptable reliability. Practitioners may utilize the two-load model when utilizing the BS method using the swing sensor, although further research is needed to examine the relationship between LVP variables and batting performance.

Resistance exercise eliciting muscle damage results in an immune response, leading to increases in circulating cytokines, and immune cell mobilization. Classical monocytes respond to muscle damage, however, little is known about the intermediate or nonclassical monocyte response to resistance exercise. Moreover, the impact of polyphenol supplementation in conjunction with resistance exercise on the innate immune response is unknown. The purpose of this study was to examine the immune response following resistance exercise with (PPB) and without (PL) polyphenol supplementation. Thirty-nine untrained men were randomized into three groups: PPB (n=13, 21.8±2.5yrs, 171.2±5.5cm, 71.2±8.2kg), PL (n=15, 21.6±2.5yrs, 176.5±4.9cm, 84.0±15.7kg) or a control group (CON) (23.3±4.1yrs, 173.6±12.0cm, 77.8±15.6kg). Blood samples were obtained pre- (PRE), immediately- (IP), 1- (1H), 5- (5H), 24- (24H), 48- (48H) and 96- (96H) hours postexercise (PPB/PL). CON rested for one hour between PRE and IP blood draws. Changes in granulocyte and monocyte subset proportions and adhesion characteristics (CD11b) were assessed via flow cytometry, while plasma cytokine concentrations and markers of muscle damage were analyzed via multiplex and spectrophotometric assays, respectively. Creatine Kinase and myoglobin were elevated at each time point for PPB and PL (p < 0.050). Monocyte chemoattractant protein-1 was significantly elevated at IP in PPB (p = 0.005) and PL (p = 0.006) and significantly greater than CON at 5H (PPB: p < 0.001; PL: p = 0.006). Granulocyte proportions were elevated at 1H (p < 0.001), 5H (p < 0.001) and 24H (p = 0.005; p = 0.006) in PPB and PL, respectively. Classical monocyte proportions were lower in PPB (p = 0.008) and PL (p = 0.003) than CON at IP, and significantly greater than CON at 1H (PPB: p = 0.002; PL: p = 0.006). Nonclassical monocyte proportions were significantly greater in PPB (p = 0.020) and PL (p = 0.028) than CON at IP. Intermediate monocyte proportions were significantly greater in PPB (p = 0.034) and PL (p = 0.001) than CON at IP, and significantly lower than CON at 1H (PPB: p = 0.003; PL: p = 0.008). Intermediate monocyte proportions were also significantly greater in PPB than CON at 24H (p = 0.016) and 48H (p = 0.007). At PRE, CD11b expression was significantly lower in the PPB group than CON and PL for intermediate (p = 0.017; p = 0.045) and nonclassical (p < 0.001, p = 0.019) monocytes, respectively. When groups were combined, CD11b expression was significantly elevated from PRE at IP (p < 0.001) and 1H (p = 0.015) on granulocytes. CD11b expression on classical monocytes was significantly elevated compared to PRE at 1H (p < 0.001), 5H (p = 0.033) and 24H (p = 0.004) when groups were combined. CD11b expression on intermediate monocytes was significantly elevated compared to PRE at 1H (p < 0.001) when groups were combined. Intermediate and nonclassical monocyte proportions also showed significant positive correlations with markers of muscle damage (r = 0.361 to 0.775, p < 0.05). Results indicated that resistance exercise in novice lifters may elicit a selective mobilization of intermediate monocytes at 24h and 48H, and that muscle damage may be related to increases in intermediate and nonclassical monocytes. In addition, polyphenol supplementation appeared to suppress CD11b expression on monocytes to resistance exercise.

INTRODUCTION: The nuclear factor kappa B (NF-κβ) signaling cascade is responsible for mediating stress-activated catabolic effects of Tumor Necrosis Factor Alpha (TNF-α) downstream of the TNF receptor (TNFR1). NF-κβ transcription factor remains inhibited in the cytosol of the muscle and can be stimulated for translocation and transcription by a variety of external stimuli, most notably by pro-inflammatory cytokines and oxidative stress. Nevertheless, currently there is a gap in the literature with regard to the time course effect of NF-κβ signaling following acute resistance exercise in humans. PURPOSE: To observe the effects of an acute lower-body resistance exercise protocol and subsequent recovery on intramuscular NF- κβ signaling. METHODS: Twenty-eight untrained males were assigned to either a control (CON; n=11) or exercise group (EX; n=17) and completed a lower-body resistance exercise protocol consisting of the back squat, leg press, and leg extension exercises. Skeletal muscle microbiopsies were obtained from the vastus lateralis pre-exercise (PRE), 1-hour (1HR), 5-hour (5HR), and 48-hours (48HR) post-resistance exercise. Multiplex signaling assay kits (EMD Millipore, Billerica, MA, USA) were used to quantify the total protein (TNFR1, c-Myc) or phosphorylation status of proteins (IKKa/b, NF- κβ, IkB) specific to apoptotic signaling pathways using MAGPIX® (Luminex, Austin, TX, USA). Repeated measures ANOVA analysis was used to determine the effects of the exercise bout on intramuscular signaling at each timepoint. Additionally, change scores were analyzed by magnitude based inferences to determine a mechanistic interpretation. RESULTS: Repeated measures ANOVA indicated a trend for a two way interaction between the EX and CON Group (p=0.064). Magnitude based inferences revealed a "Very Likely" increase in total c-Myc from PRE-5H and a "Likely" increase in IkB phosphorylation from PRE-5H. CONCLUSION: Results indicate that c-Myc transcription factor and phosphorylation of IkB are elevated following acute intense resistance exercise in untrained males. These data suggest that NF- κβ signaling plays a role in ribosome biogenesis and skeletal muscle regeneration following resistance exercise in young untrained males.

The immune system has been implicated in recovery and muscle regeneration following exercise. In response to muscle damage, the immune system responds with an increase in circulating pro-inflammatory cytokines with the goal of recruiting leukocytes to the damaged area. Tumor Necrosis Factor-alpha (TNF-α), in particular, has been shown to be implicated in both muscle regeneration and muscle wasting. However, it remains unclear whether TNF-α is responsible for the age-related losses in muscle size and function. Also, due to the high clearance rate of TNF-α from circulation, analyzing the circulating levels of soluble TNF-α receptors 1 and 2 (STNFR1 and STNFR2) may provide a better indication of inflammatory events. Therefore, the purpose of this study was to compare changes in circulating levels of TNF-α, STNFR1, and STNFR2 following an acute muscle damaging intervention in young age (YA) and middle-aged (MA) males. Recreationally active young (YA; N=9, 21.8 ± 2.2 y, 179.5 ± 4.9 cm, 91.2 ± 12.2 kg, 21.8 ± 4.3% BF) and middle-aged (MA; N=10, 47.0 ± 4.4 y, 176.8 ± 7.6 cm; 96.0 ± 21.5 kg, 25.4 ± 5.3% BF) males completed an acute muscle damaging protocol (MDP). Blood samples were obtained at baseline (BL), immediately (IP), 30 minutes (30P), 60 minutes (60P), 120 minutes (120P), 24 hours (24H), and 48 hours (48H) post-MDP. Lower body performance was analyzed via isokinetic dynamometer at BL, IP, 120P, 24H, and 48H. No significant group x time interactions or main group effects were observed for TNF-α, STNFR1, STNFR2 or any marker of muscle damage. When collapsed across groups, plasma lactate was significantly elevated at IP (p < 0.001) and 30P (p = 0.003); serum myoglobin was increased at 30P (p = 0.002), 60P (p = 0.001), and 120P (p = 0.007); creatine kinase was elevated at 24H (p = 0.001) and 48H (p = 0.005). Plasma concentrations of TNF-α were unchanged following MDP. With both groups combined, serum STNFR1 was decreased at 30P (p = 0.001) and increased at 48H (p = 0.028). Serum STNFR2 was decreased at 30P (p = 0.008), 60P (p = 0.003), and 120P (p = 0.002). The results of this study indicate that the TNF-α and STNFRs response to exercise is similar between young and middle-aged males. Measuring STNFRs may be a more appropriate method of assessing the acute inflammatory response to muscle damage. In addition, an acute bout of exercise may attenuate ectodomain shedding of TNFR1 and TNFR2.