Early Life Androgen Administration Attenuates Aging Related Declines in Muscle Protein Synthesis

PURPOSE

This study examined the acute and long-term effects of nandrolone decanoate (ND) on fractional synthetic rates (FSR).

METHODS

Male C57BL/6 mice were randomized into ND (n = 20) or sham (n = 20) groups. ND injections (10 g·kg-1·wk-1) started at 7-month of ages and continued for 6-weeks. Ten animals from each group were randomly separated and examined 1-week following drug cessation. The remaining animals were examined at 16-months of age. Animals were injected IP with 1.5 ml of deuterated water 24-h prior to euthanasia. The kidney, liver, heart, gastrocnemius, and soleus were extracted. Samples were analyzed for deuterated alanine enrichment in the bound protein and intracellular fraction by LC-MS/MS to measure estimated FSR (fraction/day [F/D]) of mixed tissue PS.

RESULTS

One-way analysis of variance, with treatment and age as fixed factors, indicated that kidney FSR was (p = 0.027) greater in ND (0.41 ± 0.02 F/D) than sham (0.36 ± 0.014F/D) and higher (p = 0.003) in young (0.42 ± 0.2 F/D) than old (0.35 ± 0.01 F/D). Liver and heart FSR were greater (p's ≤ 0.001) in young (0.79 ± 0.06 F/D, and 0.13 ± 0.01 F/D, respectively) compared to old (0.40 ± 0.01 F/D and 0.09 ± 0.01 F/D, respectively), but not between ND and sham. Gastrocnemius FSR was (p ≤ 0.001) greater in young (0.06 ± 0.01 F/D) compared to old (0.03 ± 0.002 F/D), and greater (p = 0.006) in ND (0.05 ± 0.01 F/D) compared to sham (0.04 ± 0.003 F/D). Soleus FSR rates were greater (p = 0.050) in young (0.13 ± 0.01 F/D) compared to old (0.11 ± 0.003 F/D) but, not between ND (0.12 ± 0.01 F/D) and sham (0.12 ± 0.01 F/D). Old animals who had received ND displayed elevated FSR in the gastrocnemius (p = 0.054) and soleus (p = 0.024).

CONCLUSIONS

ND use in young adult animals appeared to maintain long-term elevations in FSR in muscle during aging.

Exercise combined with electrical stimulation for the treatment of chronic ankle instability - A randomized controlled trial

PURPOSE

To compare the short, medium, and long-term effects of balance exercises combined with either peroneal neuromuscular electrical stimulation (NMES) or peroneal transcutaneous electrical nerve stimulation (TENS) on dynamic postural control and patient reported outcome measures (PROMs) in patients with chronic ankle instability (CAI).

METHODS

Thirty-four participants with CAI were randomly assigned to a 12-session home based exercise program combined with NMES (Ex-NMES) or TENS (Ex- TENS). Baseline postural control was tested with the modified Star Excursion Balance Test (mSEBT) and time to stabilization (TTS) after a single-leg drop-jump. The self-reported function was measured using the Cumberland Ankle Instability Tool (CAIT), the Identification of Functional Ankle Instability (IdFAI), and the Sports subscale of the Foot and Ankle Ability Measure (FAAMSport).

RESULTS

Both groups showed significant improvements in all self-reported outcome measures at the 12-month follow-up. Subjects in the Ex-NMES group had significantly better IdFAI (-4.2 [95% CI -8.1, -0.2]) and FAAMSport (13.7 [95% CI 2.2, 25.2]) scores at 6- and 12-month follow-up, respectively, compared to the Ex-TENS group. Medium to large between-group effect sizes were observed in self-reported functional outcomes and the mSEBT.

CONCLUSION

The consistent trend of improvement in self-reported functional outcomes when training is combined with NMES compared with training with TENS may indicate a potential benefit that should be further investigated as a treatment for patients with CAI.

Comparison of Force Measures Between Start Position, Transition Phase, and Midthigh Pull With Weightlifting Performance During Israel National Competition

ABSTRACT

Ben-Zeev, T, Sadres, E, and Hoffman, JR. Comparison of force measures between start position, transition phase, and midthigh pull with weightlifting performance during Israel National Competition. J Strength Cond Res 37(11): 2200-2205, 2023-This study compared the relationship between peak force (PKF) and rate of force development (RFD) at isometric start position pull (ISPP), isometric transition position pull (ITPP), and isometric midthigh pull (IMTP) with the snatch (SN), clean and jerk (C&J), and total score (TOT) in 30 national and international Israeli weightlifters (18 men and 12 women). All measures were collected either 1 week before or 1 week after the Israel weightlifting championship. A significant correlation was observed between peak force at all pull positions and performance in the SN, C&J, and TOT for men, women, and both sexes combined ( p < 0.001). The correlations were all very strong (e.g., r values all above 0.90) for both ISPP and ITPP, and all weightlifting performance variables, whereas the correlation between IMTP and weightlifting performance ranged from moderate ( r = 0.69) to strong ( r = 0.89). In addition, significant differences were observed between the correlation coefficient value in ISPP and ITPP with the TOT score compared with the correlations observed in IMTP ( z = 0.7, p = 0.046, and z = 1.7, p = 0.049, respectively). Significant differences were also observed in the women group for ISPP for the SN and TOT score compared with the correlation in IMTP ( z = 1.72, p = 0.043, and z = 1.75, p = 0.040, respectively). Rate of force development at 250 milliseconds significantly ( p values <0.05) correlated with the SN, C&J, and TOT in women ( r 's = 0.65, 0.68, and 0.67, respectively), and when both sexes were combined ( r 's = 0.59, 0.61, and 0.60, respectively), but not for the men. Results of this investigation indicated the importance of isometric force capabilities at ISPP and ITPP for weightlifting performance.

The effect of supraphysiological dose of nandrolone decanoate administration on the inflammatory, neurotrophin and behavioral response in adult and old male mice

This study examined the effect of 6 weeks of supraphysiological nandrolone decanoate (ND) administration in adult mice (7 months) on cognitive function and neuroinflammation during aging. Male C57BL/6 mice were randomized into ND (10 mg·kg-1·wk-1) or control (CTL) groups. Half of the mice were tested at a young (Y) age (ND-Y and CTL-Y), 1 week following final ND administration, while the remaining mice were tested at 16 months (O) (ND-O and CTL-O). Learning and memory were better in young mice compared to older mice, regardless of treatment. ND-O displayed decreased anxiety as compared to all other groups. TNFα and IL1β expression were higher in older mice, regardless of treatment. ND administration in young mice appeared to attenuate the neuroinflammatory response in aging mice as evidenced by decreased COX2, IL-4 and increased IL-10 expression in ND-O compared to CTL-O. BDNF AR and ER expression increased in ND-O compared to CTL-O. Results of the study indicated that supraphysiological ND administration had no negative effect on learning and memory but may attenuate anxiety in older mice. In addition, ND administration in young adult mice may attenuate the inflammatory response during aging, which may be related to elevations in both AR and ER expression.

New Perspectives in Resistance Training Periodization: Mixed Session vs. Block Periodized Programs in Trained Men

ABSTRACT

Bartolomei, S, Zaniboni, F, Verzieri, N, and Hoffman, JR. New perspectives in resistance training periodization: mixed session vs. block periodized programs in trained men. J Strength Cond Res 37(3): 537-545, 2023-The purpose of this investigation was to compare the effects of 2 different periodized resistance training programs on maximal strength, power, and muscle architecture, in trained individuals. Twenty-two resistance-trained men were randomly assigned to either a mixed session training group (MSP; n = 11; age = 23.7 ± 2.6 years; body mass = 80.5 ± 9.8 kg; height = 175.5 ± 6.1 cm) or a block periodization group (BP; n = 11; age = 25.7 ± 4.6 years; body mass = 81.1 ± 10.7 kg; height = 176.8 ± 8.4 cm). Both training programs were 10 weeks in duration and were equated in volume. Each training session of the MSP focused on power, maximal strength, and hypertrophy, whereas each mesocycle within the BP focused on one of these components. Subjects were assessed for body composition, muscle architecture, maximal strength, and power. In addition, perceived training load, and training volume were calculated. Subjects in MSP experienced greater improvements in fat free mass ( p = 0.021), muscle thickness of the pectoralis and vastus lateralis ( p < 0.05), and a greater improvement in 1RM bench press ( p < 0.001; +8.6% in MSP and +2% in BP) than in BP. By contrast, BP resulted in greater improvements in vertical jump ( p = 0.022; +7.2%) compared with MSP (+1.2%). No significant differences were noted between the groups for perceived training load ( p = 0.362) nor training volume ( p = 0.169). Results of this study indicated that in a 10-week training study, MSP may enhance muscle hypertrophy and maximal strength to a greater extent than BP, with the same training volume and perceived training load. However, BP may be more effective for vertical jump improvement.

Effects of Concurrent Resistance and Endurance Training Using Continuous or Intermittent Protocols on Muscle Hypertrophy: Systematic Review With Meta-Analysis

ABSTRACT

Monserdà-Vilaró, A, Balsalobre-Fernández, C, Hoffman, JR, Alix-Fages, C, and Jiménez, SL. Effects of concurrent resistance and endurance training using continuous or intermittent protocols on muscle hypertrophy: Systematic review with meta-analysis. J Strength Cond Res 37(3): 688-709, 2023-The purpose of this systematic review with meta-analysis was to explore the effects of concurrent resistance and endurance training (CT) incorporating continuous or intermittent endurance training (ET) on whole-muscle and type I and II muscle fiber hypertrophy compared with resistance training (RT) alone. Randomized and nonrandomized studies reporting changes in cross-sectional area at muscle fiber and whole-muscle levels after RT compared with CT were included. Searches for such studies were performed in Web of Science, PubMed, Scopus, SPORTDiscus, and CINAHL electronic databases. The data reported in the included studies were pooled in a random-effects meta-analysis of standardized mean differences (SMDs). Twenty-five studies were included. At the whole-muscle level, there were no significant differences for any comparison (SMD < 0.03). By contrast, RT induced greater type I and type II muscle fiber hypertrophy than CT when high-intensity interval training (HIIT) was incorporated alone (SMD > 0.33) or combined with continuous ET (SMD > 0.27), but not compared with CT incorporating only continuous ET (SMD < 0.16). The subgroup analyses of this systematic review and meta-analysis showed that RT induces greater muscle fiber hypertrophy than CT when HIIT is included. However, no CT affected whole-muscle hypertrophy compared with RT.

Dynamic postural control in individuals with and without chronic ankle instability-do the modified star-excursion balance test and jump-landing stabilization have the same control mechanism?

OBJECTIVE

To examine the relationship between two dynamic postural tasks in subjects with and without chronic ankle instability (CAI).

DESIGN

Cross-sectional study.

SETTING

Biomechanics lab.

PARTICIPANTS

Thirty subjects with CAI and 30 healthy controls.

MAIN OUTCOME MEASURE

Performance of two dynamic postural control tests: the modified Star-Excursion Balance Test (mSEBT) and an assessment of a single limb jump-landing on a force plate that yielded two outcomes: time to stabilization (TTS) and the absolute average force in the mediolateral plane during the first 0.4 s after landing (AAF_ML).

RESULTS

In the CAI group, a significant correlation was found between the mSEBT score and the AAF_ML (ρ = -0.54, p < 0.01), but not between the mSEBT or TTS or between the AAF_ML and the TTS. However, in the control group, a significant correlation was found between AAF_ML and the TTS (ρ = 0.43, p < 0.05), but not between the mSEBT and TTS or between the mSEBT and AAF_ML.

CONCLUSION

These results suggest that there is no association between the different dynamic balance tasks. The different pattern of association in individuals with CAI may indicate altered central neural control. Clinicians and researchers should therefore not use a single task to assess dynamic postural control.

Role of β-Alanine Supplementation on Cognitive Function, Mood, and Physical Function in Older Adults; Double-Blind Randomized Controlled Study

This study investigated 10 weeks of β-alanine (BA) supplementation on changes in cognitive function, mood, and physical performance in 100 older adults (70.6 ± 8.7 y). Participants were randomized into a BA (2.4 g·d^-1) or placebo (PL) group. Testing occurred prior to supplementation (PRE), at the midpoint (MID), and at week-10 (POST). Participants completed cognitive function assessments, including the Montreal cognitive assessment (MOCA) and the Stroop pattern recognition test, at each testing session. Behavioral questionnaires [i.e., the profile of mood states, geriatric depression scale (GDS), and geriatric anxiety scale (GAS)] and physical function assessments (grip strength and timed sit-to-stand) were also conducted. No difference between groups was noted in MoCA scores (p = 0.19). However, when examining participants whose MOCA scores at PRE were at or below normal (i.e., ≤26), participants in BA experienced significant improvements in MOCA scores at MID (13.6%, p = 0.009) and POST (11.8%, p = 0.016), compared to PL. No differences were noted in mood scores, GAS, or any of the physical performance measures. A significant decrease was observed in the GDS for participants consuming BA but not in PL. Results suggested that BA supplementation can improve cognitive function in older adults whose cognitive function at baseline was at or below normal and possibly reduce depression scores.

The BDNF Val66Met Polymorphism is a Relevant, But not Determinant, Risk Factor in the Etiology of Neuropsychiatric Disorders - Current Advances in Human Studies: A Systematic Review

Brain-derived neurotrophic factor (BDNF) is the brain's most-produced neurotrophin during the lifespan, essentially involved in multiple mechanisms of nervous system development and function. The production/release of BDNF requires multi-stage processing that appears to be regulated at various stages in which the presence of a polymorphism "Val66Met" can exert a critical influence.

Aim

To synthesize the knowledge on the BDNF Val66Met polymorphism on intracellular processing and function of BDNF.

Methods

We performed a systematic review and collected all available studies on the post-translation processes of BDNF, regarding the Val66Met polymorphism. Searches were performed up to 21st March 2021.

Results

Out of 129 eligible papers, 18 studies addressed or had findings relating to BDNF post-translation processes and were included in this review.

Discussion

Compilation of experimental findings reveals that the Val66Met polymorphism affects BDNF function by slightly altering the processing, distribution, and regulated release of BDNF. Regarding the critical role of pro-BDNF as a pro-apoptotic factor, such alteration might represent a risk for the development of neuropsychiatric disorders.

Reliability and Validity of Patient-Reported Outcome Measures for Ankle Instability in Hebrew

Background

The International Ankle Consortium has recommended several instruments for assessing and diagnosing chronic ankle instability. These include the Ankle Instability Instrument (AII), Cumberland Ankle Instability Tool (CAIT), Identification of Functional Ankle Instability (IdFAI), and Foot and Ankle Ability Measure (FAAM). This study aimed to translate, culturally adapt, and assess the reliability, validity, discriminative power, and classification agreement of the Hebrew online versions of the AII, CAIT, IdFAI, and FAAM.

Material/Methods

After translation and cross-cultural adaptation of the questionnaires, we recruited 87 participants with self-reported ankle disorders to evaluate the psychometric properties of the questionnaires. To evaluate each questionnaire’s discriminative power, we recruited 75 healthy participants. Reliability was assessed by calculating internal consistency (Cronbach’s alphas) and test-retest intraclass correlation coefficients. Convergent and divergent validity were assessed by Spearman’s correlation between each instrument and the Short-Form-12 (SF-12) score for physical and mental components, respectively.

Results

All instruments had acceptable internal consistency (α>0.7) and good test-retest reliability (ICC_2,1>0.8), except for the IdFAI (ICC_2,1=0.73). All instruments had moderate convergent validity (ρ>0.4 with SF-12 physical component) except for AII (ρ=0.36). No instrument was correlated with the SF-12 mental component score (good divergent validity, ρ<0.3). All instruments had excellent discriminative power (area under the receiver operator characteristic curve >0.9). Strong correlations were found between all instruments.

Conclusions

The Hebrew online versions of the AII, CAIT, IdFAI, and FAAM are valid, consistent, and reliable and may be used in research or clinical settings.

The Effect of Exercise on Neurogenesis in the Brain

The connection between physical exercise and the brain has long been studied. The evidence showing that physical exercise plays a significant role on neurogenesis and cognitive function has primarily been based on research examining aerobic exercise. In this review, we described three exercise modalities: aerobic, anaerobic, and resistance exercise and their impact on brain plasticity and cognitive function. While each of these exercise modalities have been demonstrated to positively influence brain plasticity and cognitive function, the specific mechanism that stimulates these changes appear to differ to some degree between these training modalities. The effect of aerobic and anaerobic exercise appears to be primarily mediated by changes in expression of brain-derived neurotrophic factor (BDNF), lactate, vascular endothelial growth factor (VEGF), and several additional proteins within the brain. However, resistance exercise appears to influence brain plasticity by myokines such as irisin, insulin-growth factor-1 (IGF1), and BDNF that are secreted from skeletal tissue and stimulate neurogenesis within the brain. In addition to the various training modes, manipulation of various acute program variables such as intensity, volume, and rest intervals leads to numerous possible training paradigms that can provide a different stimulus for neurogenesis. This review focuses on the three primary training modes and their connection to neurogenesis and cognitive function.

Heat-Stress Preconditioning Attenuates Behavioral Responses to Psychological Stress: The Role of HSP-70 in Modulating Stress Responses

Exposure to high ambient temperature is a stressor that influences both biological and behavioral functions and has been previously shown to have an extensive impact on brain structure and function. Physiological, cellular and behavioral responses to heat-stress (HS) (40-41 °C, 2 h) were evaluated in adult male Sprague-Dawley rats. The effect of HS exposure before predator-scent stress (PSS) exposure (i.e., HS preconditioning) was examined. Finally, a possible mechanism of HS-preconditioning to PSS was investigated. Immunohistochemical analyses of chosen cellular markers were performed in the hippocampus and in the hypothalamic paraventricular nucleus (PVN). Plasma corticosterone levels were evaluated, and the behavioral assessment included the elevated plus-maze (EPM) and the acoustic startle response (ASR) paradigms. Endogenous levels of heat shock protein (HSP)-70 were manipulated using an amino acid (L-glutamine) and a pharmacological agent (Doxazosin). A single exposure to an acute HS resulted in decreased body mass (BM), increased body temperature and increased corticosterone levels. Additionally, extensive cellular, but not behavioral changes were noted. HS-preconditioning provided behavioral resiliency to anxiety-like behavior associated with PSS, possibly through the induction of HSP-70. Targeting of HSP-70 is an attractive strategy for stress-related psychopathology treatment.

Manipulation of Dietary Intake on Changes in Circulating Testosterone Concentrations

Elevations in the circulating concentration of androgens are thought to have a positive effect on the anabolic processes leading to improved athletic performance. Anabolic-androgenic steroids have often been used by competitive athletes to augment this effect. Although there has been concerted effort on examining how manipulating training variables (e.g., intensity and volume of training) can influence the androgen response to exercise, there has been much less effort directed at understanding how changes in both macronutrient and micronutrient intake can impact the androgen response. Thus, the focus of this review is to examine the effect that manipulating energy and nutrient intake has on circulating concentrations of testosterone and what the potential mechanism is governing these changes.

Sex-Based Performance Responses to an Acute Sprint Interval Cycling Training Session in Collegiate Athletes

There are limited data pertaining to the effects of sex on sprint interval cycling (SIC) training session performance. Purpose: We investigated sex-based differences on sprint interval cycling (SIC) performance in collegiate soccer players. Methods: Twelve men and twelve women completed two identical lab trials, 7-14 days apart. The first lab session served as familiarization, "dry run," trial. Reported data were collected and analyzed during the second, "testing" SIC training trial. Each SIC training session was comprised of a warm-up, at 50 revolutions per min (RPM) with no resistance, and six repeated 30-s Wingate Anaerobic Tests (WAnT) separated by a 4-min recovery period between each sprint. Results: Significant (P ≤ .05) sex differences were observed in peak power (PP), peak power relative to body mass (RPP), mean power (MP), mean power relative to body mass (RMP) but not in peak power relative to fat free mass (FFMPP). When WAnT bouts 2-6 were expressed as %Δ of WAnT1, there were no significant (P > .05) differences between the sexes across all performance variables. Further, Cohen's d statistics demonstrated only trivial and small effect size between the groups. Average HR and RPE were not significantly (P > .05) different between the sexes. Correlational analysis revealed a significant (P ≤ .05) relationship between FFM, and PP and MP. Conclusion: Although overall performance may be affected by a number of physiological mechanisms, the results of the current study indicate that differences between men and women soccer players performing SIC training, are likely attributed to differences in body composition.

Anabolic-Androgenic Steroid Use in Sports, Health, and Society

This consensus statement is an update of the 1987 American College of Sports Medicine (ACSM) position stand on the use of anabolic-androgenic steroids (AAS). Substantial data have been collected since the previous position stand, and AAS use patterns have changed significantly. The ACSM acknowledges that lawful and ethical therapeutic use of AAS is now an accepted mainstream treatment for several clinical disorders; however, there is increased recognition that AAS are commonly used illicitly to enhance performance and appearance in several segments of the population, including competitive athletes. The illicit use of AAS by competitive athletes is contrary to the rules and ethics of many sport governing bodies. Thus, the ACSM deplores the illicit use of AAS for athletic and recreational purposes. This consensus statement provides a brief history of AAS use, an update on the science of how we now understand AAS to be working metabolically/biochemically, potential side effects, the prevalence of use among athletes, and the use of AAS in clinical scenarios.

The Val66 and Met66 Alleles-Specific Expression of BDNF in Human Muscle and Their Metabolic Responsivity

Brain-derived neurotrophic factor (BDNF) plays an essential role in nervous system formation and functioning, including metabolism. Present only in humans, the “Val66Met” polymorphism of the BDNF gene (BDNF) is suggested to have a negative influence on the etiology of neurological diseases. However, this polymorphism has only been addressed, at the molecular level, in nonhuman models. Knowledge about Val66- and Met66-variant differences, to date, has been achieved at the protein level using either cell culture or animal models. Thus, the purpose of our study was to analyze the impact of the Val66Met polymorphism on BDNF expression in healthy humans and compare the allele-specific responses to metabolic stress. Muscle biopsies from 13 male recreational athletes (34 ± 9 years, 1.80 ± 0.08 m, 76.4 ± 10.5 kg) were obtained before and immediately following a VO₂max test. Allele-specific BDNF mRNA concentrations were quantified by droplet digital PCR (ddPCR) in heterozygous and homozygous subjects. The results indicated that BDNF expression levels were influenced by the genotype according to the presence of the polymorphism. BDNF expression from the Met66-coding alleles, in heterozygotes, was 1.3-fold lower than that from the Val66-coding alleles. Total BDNF mRNA levels in these heterozygotes remained below the whole sample’s mean. A partial dominance was detected for the Val66-coding variant on the Met66-coding’s. BDNF expression levels decreased by an average of 1.8-fold following the VO₂max test, independent of the individual’s genotype. The results of this study indicate that metabolic stress downregulates BDNF expression but not plasma BDNF concentrations. No correlation between expression level and plasma BDNF concentrations was found.

β-Alanine Supplementation Attenuates the Neurophysiological Response in Animals Exposed to an Acute Heat Stress

The effect of 30 days of β-alanine supplementation on neurophysiological responses of animals exposed to an acute heat stress (HS) was examined. Animals were randomized to one of three groups; exposed to HS (120 min at 40-41 °C) and fed a normal diet (EXP; n = 12); EXP and supplemented with β-alanine (EXP + BA; n = 10); or not exposed (CTL; n = 10). Hippocampal (CA1, CA3 and DG) and hypothalamic (PVN) immunoreactive (ir) cell numbers of COX2, IBA-1, BDNF, NPY and HSP70 were analyzed. Three animals in EXP and one in EXP-BA did not survive the HS, however no significant difference (p = 0.146) was noted in survival rate in EXP + BA. The % change in rectal temperature was significantly lower (p = 0.04) in EXP + BA than EXP. Elevations (p's < 0.05) in COX-2, IBA-1 and HSP70 ir-cell numbers were noted in animals exposed to HS in all subregions. COX-2 ir-cell numbers were attenuated for EXP + BA in CA1 (p = 0.02) and PVN (p = 0.015) compared to EXP. No difference in COX-2 ir-cell numbers was noted between CTL and EXP + BA at CA1. BDNF-ir cell numbers in CA1, DG and PVN were reduced (p's < 0.05) during HS compared to CTL. No difference in BDNF-ir cell numbers was noted between EXP + BA and CTL in CA3 and PVN. NPY-ir density was reduced in exposed animals in all subregions, but NPY-ir density for EXP-BA was greater than EXP in CA3 (p < 0.001) and PVN (p = 0.04). β-Alanine supplementation attenuated the thermoregulatory and inflammatory responses and maintained neurotrophin and neuropeptide levels during acute HS. Further research is necessary to determine whether β-alanine supplementation can increase survival rate during a heat stress.

Continuous and interval training attenuate encephalomyelitis by separate immunomodulatory mechanisms

BACKGROUND

Studies have reported beneficial effects of exercise training on autoimmunity, and specifically on multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE). However, it is unknown whether different training paradigms affect disease course via shared or separate mechanisms.

OBJECTIVE

To compare the effects and mechanism of immune modulation of high intensity continuous training (HICT) versus high intensity interval training (HIIT) on systemic autoimmunity in EAE.

METHODS

We used the proteolipid protein (PLP)-induced transfer EAE model to examine training effects on the systemic autoimmune response. Healthy mice performed HICT or HIIT by running on a treadmill. Lymph-node (LN)-T cells from PLP-immunized trained- versus sedentary donor mice were transferred to naïve recipients and EAE clinical and pathological severity were assessed. LN cells derived from donor trained and sedentary PLP-immunized mice were analyzed in vitro for T-cell activation and proliferation, immune cell profiling, and cytokine mRNA levels and cytokine secretion measurements.

RESULTS

Both HICT and HIIT attenuated the encephalitogenicity of PLP-reactive T cells, as indicated by reduced EAE clinical severity and inflammation and tissue pathology in the central nervous system, following their transfer into recipient mice. HICT caused a marked inhibition of PLP-induced T-cell proliferation without affecting the T-cell profile. In contrast, HIIT did not alter T-cell proliferation, but rather inhibited polarization of T cells into T-helper 1 and T-helper 17 autoreactive populations.

INTERPRETATION

HICT and HIIT attenuate systemic autoimmunity and T cell encephalitogenicity by distinct immunomodulatory mechanisms.

Effect of β-Alanine Supplementation on Monocyte Recruitment and Cognition During a 24-Hour Simulated Military Operation

Wells, AJ, Varanoske, AN, Coker, NA, Kozlowski, GJ, Frosti, CL, Boffey, D, Harat, I, Jahani, S, Gepner, Y, and Hoffman, JR. Effect of β-alanine supplementation on monocyte recruitment and cognition during a 24-hour simulated military operation. J Strength Cond Res 34(11): 3042-3054, 2020-Sustained military operations (SUSOPs) result in psychological stress and cognitive dysfunction, which may be related to the recruitment of classical monocytes into the brain. This study examined the effect of beta-alanine (BA) on cognition and monocyte recruitment during a simulated 24-hour SUSOP. Nineteen healthy men ingested 12-g/d BA or placebo for 14 days before an SUSOP. Monocyte chemoattractant protein-1 (MCP-1), C-C chemokine receptor-2 (CCR2), and macrophage-1-antigen (CD11b) expression were assessed through multiplex assay and flow cytometry. Psychological stress and cognition were assessed through Automated Neuropsychological Assessment Metrics (ANAM). A composite measure of cognition (COGcomp) was generated from throughput scores extracted from 7 ANAM cognitive tests. Assessments occurred at baseline (0H), 12 hours (12H), 18 hours (18H), and 24 hours (24H). Significance was accepted at p ≤ 0.05. No significant effect of BA was noted for any variable (p's > 0.05). The frequency and severity of symptoms of psychological stress increased significantly at 18 and 24H compared with 0 and 12H (p's < 0.05). COGcomp decreased significantly at 18 and 24H compared with 0 and 12H (p's ≤ 0.001). MCP-1 peaked at 18H was significantly lower at 24H compared with 18H but remained elevated at 24H compared with 0H (p's < 0.001). CCR2 expression was significantly lower at 12 (p = 0.031), 18, and 24H (p's < 0.001). CD11b expression was significantly higher at 12H (p = 0.039) and 24H (p's = 0.003). MCP-1 was negatively associated with COGcomp (β = -0.395, p = 0.002, r2 = 0.174). Neither CCR2 or CD11b was related to COGcomp (p's > 0.05). Cognitive dysfunction during SUSOPs is related to serum concentrations of MCP-1 but is not influenced by BA supplementation.

Evaluation of a Reactive Agility Assessment Device in Youth Football Players

Hoffman, JR. Evaluation of a reactive agility assessment device in youth football players. J Strength Cond Res 34(12): 3311-3315, 2020-The purpose of this study was to examine the reliability and validity of the Blazepod reactive agility device on sport-specific movements in competitive youth football players. Thirty-one male athletes (16.7 ± 1.5 years; 179.4 ± 7.0 cm; 75.0 ± 21.0 kg), all members of a youth tackle football team, volunteered to participate in this study. Subjects performed 3 reactive agility drills (side shuffle reactive agility, 1-m reactive agility, and 3-m reactive agility) at least 72 hours apart. In addition, all subjects also performed 3 traditional agility exercises: proagility, T drill, and L drill. These sessions were part of the offseason conditioning program for the football team that involved sport-specific drills. All assessments occurred following a warm-up and conducted in the same order on each occasion. To assess the validity of the reactive agility drills, the head coach was asked to rank the football playing and agility ability of the players participating in the study. The intraclass correlation coefficient values indicated that all 3 reactive agility drills displayed excellent reliability (r's ranging from 0.833 to 0.884). The measurement error was smaller than the individual variability, indicating that measurement error had a very limited effect on the results. Subjective rankings for agility significantly correlated with each of the agility and reactive agility measurements. Results of this study indicate that the Blazepod reactive agility device is a reliable measure of reactive agility performance and are consistent with the coach's perception of the athlete's agility performance, thus demonstrating construct validity.

Changes in Hippocampal Androgen Receptor Density and Behavior in Sprague-Dawley Male Rats Exposed to a Low-Pressure Blast Wave

Objective

The purpose of this study was to examine the effect of exposure of a low-intensity blast wave on androgen receptor (AR) density in the hippocampus and the potential influence on behavioral and cognitive responses.

Methods

Sprague-Dawley rats were randomly assigned to either a blast exposed group (n = 27) or an unexposed (control) group (n = 10). Animals were treated identically, except that rats within the control group were not exposed to any of the characteristics of the blast wave. Behavior measures were conducted on day seven post-exposure. The rats were initially assessed in the elevated plus maze followed by the acoustic startle response paradigm. Spatial memory performance using the Morris water-maze test was assessed at 8-days post-exposure, for seven consecutive days. Following all behavioral tests AR immunofluorescence staining was performed in different hippocampal subregions.

Results

A significant elevation in anxiety index (p < 0.001) and impaired learning (p < 0.015) and spatial memory (p < 0.0015) were noted in exposed rats. In addition, a significant attenuation of the AR was noted in the CA1 (p = 0.006) and dentate gyrus (p = 0.031) subregions of the hippocampus in blast exposed animals. Correlational analyses revealed significant associations between AR and both anxiety index (r = -.36, p = 0.031) and memory (r = -0.38, p = 0.019).

Conclusions

The results of this study demonstrate that exposure to a low-pressure blast wave resulted in a decrease in AR density, which was associated with significant behavioral and cognitive changes.

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.

BDNF Val66Met Polymorphism, the Allele-Specific Analysis by qRT-PCR - a Novel Protocol

Background: Alteration in brain-derived neurotrophic factor (BDNF) production is a marker of neuropathological conditions, which has led to the investigation of Val66Met polymorphism occurring in the human BDNF gene (BDNF). Presently, there are no reported methods available for the analysis of Val66Met impact on human BDNF functioning. Purpose: To develop a qRT-PCR protocol for the allele-specific expression evaluation of the Val66Met polymorphism in BDNF. Methods: Using RNA extracted from muscle samples of 9 healthy volunteers (32.9 ± 10.3 y) at rest and following a maximal effort aerobic capacity exercise test, a protocol was developed for the detection of Val66/Met66 allele-specific BDNF expression in Real-Time Quantitative Reverse Transcription PCR (qRT-PCR) - relative to housekeeping genes - and validated by absolute quantification in Droplet Digital Polymerase Chain Reaction (ddPCR). Results: Differences in the relative values of BDNF mRNA were confirmed by ddPCR analysis. HPRT1 and B2M were the most stable genes expressed in muscle tissue among different metabolic conditions, while GAPDH revealed to be metabolic responsive. Conclusion: Our qRT-PCR protocol successfully determines the allele-specific detection and changes in BDNF expression regarding the Val66Met polymorphism.

The Effect of 2 Weeks of Inactivated Probiotic Bacillus coagulans on Endocrine, Inflammatory, and Performance Responses During Self-Defense Training in Soldiers

Hoffman, JR, Hoffman, MW, Zelicha, H, Gepner, Y, Willoughby, DS, Feinstein, U, and Ostfeld, I. The Effect of 2-Weeks of Inactivated Probiotic Bacillus coagulans on Endocrine, Inflammatory and Performance Responses During Self-Defense Training in Soldiers. J Strength Cond Res 33(9): 2330-2337, 2019-The effect of 2 weeks of inactivated Bacillus coagulans (iBC) ingestion on performance and inflammatory cytokines was examined during a self-defense course in soldiers. Sixteen male soldiers were randomly assigned to either iBC (n = 8) or placebo (PL; n = 8) in this double-blind study. Participants were garrisoned on base and participated in the same training tasks. Assessments were conducted in a single day before (PRE) and after the supplementation period (POST). During each testing session, participants were assessed for vertical jump power (VJP), muscle endurance, simulated casualty drag, and 2 100-m shuttle runs. Resting blood measures for testosterone, cortisol, creatine kinase, and inflammatory cytokines were also assessed. Mann-Whitney analysis of change (Δ) scores indicated no significant change (p's > 0.05) in any of the performance or blood variables. However, a trend (p = 0.089) was noted in the Δ score for VJP in iBC compared with PL. In addition, trends were observed in the change in IL-10 (p = 0.057) and IFNγ (p = 0.057). Magnitude based inferential analysis indicated that changes in VJP and simulated casualty drag were likely beneficial (90.7 and 80.4% likelihood effect, respectively) for iBC. In addition, iBC supplementation very likely augmented IL-10 concentrations, but was possibly negative for changes in IL-6, and likely negative for changes in TNFα and IFNγ. Changes in all other performance and blood markers were unclear. Results indicated that 2 weeks of iBC supplementation appeared to be beneficial for maintaining power and short-term speed performance, while attenuating the inflammatory response during intense training in a military self-defense course.

Effect of β-alanine supplementation on carnosine and histidine content in the hippocampus of 14-month-old rats

Carnosine and histidine content in the hippocampus of 14-month-old male rats was examined following 30 days of β-alanine supplementation. All animals were provided identical diets; however, 100 mg of β-alanine was mixed with glucomannan (80:20 blend) in the water of β-alanine supplemented animals. Hippocampal carnosine content was significantly greater (p = 0.005) for β-alanine compared with control, while no differences (p = 0.438) were noted in histidine content between groups. Results provide initial evidence that β-alanine supplementation increases carnosine content in the hippocampus of middle-aged rats, without compromising histidine content. β-Alanine supplementation increases hippocampal carnosine content without compromising histidine content in middle-aged rats.

Effect of Spearmint Extract Containing Rosmarinic Acid on Physical and Executive Functioning After a Tactical Operation

We examined the effect of a proprietary spearmint extract containing rosmarinic acid (PSE) on physical, cognitive, and executive functioning of study participants after a high-risk tactical operation while sleep deprived for 24 hours. Ten Operators (mean ± standard deviation: age, 35.1 ± 5.2 years; height, 177.6 ± 5.3cm; weight, 81.3 ± 9.3kg) from an elite counterterrorism unit volunteered to participate in this randomized, double-blind, parallel-design study. Participants were randomly assigned into either the PSE or placebo (PL) group and ingested 900mg/day PSE or an equivalent amount of PL for 17 days. Physical, cognitive, and executive functioning was tested before PST supplementation (PRE) and within 1 hour of the operation's conclusion (POST). Magnitude-based inferences indicated that differences between PSE and PL in jump power, reactive agility, eye-hand coordination, and cognition were unclear. However, subjective feelings of energy, alertness, and focus were very likely, likely, and possibly better for PSE than PL, respectively. There was no difference (ρ = .64) between groups in identifying the correct target; however, all participants in the PSE group correctly identified the target, whereas 60% of participants in the PL group correctly identified the target at POST. Although the results of this study do not provide conclusive evidence regarding the efficacy of PSE, they do suggest additional research is warranted in a larger sample of participants.

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.

Examining work-to-rest ratios to optimize upper body sprint interval training

The objective was to compare the metabolic influence of varying work-to-rest ratios during upper body sprint interval training (SIT). Forty-two recreationally-trained men were randomized into a training group [10 s work - 2 min of rest (10:2) or 4 min of rest (10:4), or 30 s work - 4 min of rest (30:4)] or a control group (CON). Participants underwent six training sessions over two weeks. Assessments consisted of a graded exercise test [maximal oxygen consumption (VO₂peak) and peak power output (PPO)], four constant-work rate trials [critical power, anaerobic working capacity, and electromyographic fatigue threshold], and an upper body Wingate test (mean/peak power and total work). Post-training absolute and relative VO₂peak was greater than pre-training for 30:4 (p = .005 and p = .009, respectively), but lower for CON (p = .001 and p = .006, respectively). Post-training PPO was greater in 30:4 (p < .001). No differences were observed during the constant-work rate trials or Wingate test. Traditional SIT appears to have enhanced VO₂peak in the upper body over a short-term two-week intervention.

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.

Effect of High-Dose, Short-Duration β-Alanine Supplementation on Circulating IL-10 Concentrations During Intense Military Training

Hoffman, JR, Gepner, Y, Hoffman, M, Zelicha, H, Shapira, S, and Ostfeld, I. Effect of high dose, short-duration β-alanine supplementation on circulating IL-10 concentrations during intense military training. J Strength Cond Res 32(10): 2978-2981, 2018-This study examined the effect of β-alanine as a potential anti-inflammatory agent during intense military training. Twenty soldiers (20.1 ± 0.6 years) from an elite combat unit were randomly assigned to either a β-Alanine (BA) or placebo (PL) group. Soldiers were provided with 12 g·d of either BA or PL for 7 days between 2 intensive periods of navigational training and restricted sleep. During the initial training period, soldiers navigated on average 27.8 km·d with ∼50% of their body mass in their packs for 5 days. Soldiers returned to base and began a 7-day supplementation program before departing for an additional period of intense field training. During the second period of field training, soldiers navigated 10 km·d for an additional 5 days, carrying similar loading as the initial week, performed tactical missions, and slept approximately 5 hours per day. Blood samples were obtained after the initial training period and after the second training period and analyzed for IL-10. Magnitude-based inferences that were used to provide inferences on the true effect BA may have had on IL-10 concentrations compared with PL, calculated from 90% confidence intervals. Data analysis indicated that changes in circulating IL-10 concentrations (mean difference 0.86 pg·ml) were possibly greater (57%) for BA than PL. Results of this study suggest that 1 week of high-dose BA ingestion may enhance the anti-inflammatory response during intense military training, suggesting a potential therapeutic role of BA during intense training.

Differences in muscle oxygenation between young and middle-aged recreationally active men during high-volume resistance exercise

The aim of this study was to compare muscle oxygenation of the vastus lateralis during a high-volume isokinetic resistance exercise protocol (HVP) between young adult (YA) and middle-aged adult (MA) men. Twenty recreationally trained men were assigned to either the YA (age 21.8±2.0 years, body mass 90.7±11.6 kg, body height 179±4.7 cm) or MA (age 47.0±4.4 years, body mass 96.1±21.6 kg, body height 177±7.7 cm) group. The HVP consisted of eight sets of 10 repetitions of unilateral isokinetic concentric knee extension and eccentric knee flexion at 60°·s-1. Changes in tissue hemoglobin saturation index (TSI), tissue oxygenated hemoglobin concentration (O2Hb), deoxygenated hemoglobin (HHb), and muscle oxidation index (O2Hb-HHb) were measured during the exercise session using the near-infrared spectroscopy (NIRS). Data were analyzed using two-way mix factorial analyses of variance. Prior to exercise, TSI was significantly greater (p=.024) for YA compared to MA. Significant decreases in O2Hb and O2Hb-HHb and increases in HHb were observed during each of the eight sets relative to the rest periods (p&lt;.05) for both groups. The average change during the eight sets of the HVP revealed a significantly higher (p=.036) level of HHb and a lower (p=.029) level of O2Hb-HHb for MA compared to YA. A significant negative correlation was also noted at baseline between O2Hb-HHb index and the cross-sectional area of the vastus lateralis muscle (r=-.45, p=.045). During a high- volume resistance exercise, MA experienced reduced muscle oxygen saturation levels compared to YA. These results may be attributed to reductions in local tissue oxidative capacity and reduced blood delivery occurring during middle-age, and possibly due to group differences in muscle morphology.

Association between circulating inflammatory markers and marksmanship following intense military training

Introduction

Intense military operations during deployment or training are associated with elevations in inflammatory cytokine markers. However, the influence of an inflammatory response on military-specific skills is unclear. This study examined the association between brain-derived neurotrophic factor (BDNF), glial fibrillar acidic protein, markers of inflammation, marksmanship and cognitive function following a week of intense military field training.

Methods

Twenty male soldiers (20.1±0.6 years; 1.78±0.05m; 74.1±7.9kg) from the same elite combat unit of the Israel Defense Forces volunteered to participate in this study. Soldiers completed a five-day period of intense field training including navigation of 27.8km/day with load carriages of ~50% of their body mass. Soldiers slept approximately fivehours per day and were provided with military field rations. Following the final navigational exercise, soldiers returned to their base and provided a blood sample. In addition, cognitive function assessment and both dynamic and static shooting (15 shots each) were performed following a 200 m gauntlet, in which soldiers had to use hand-to-hand combat skills to reach the shooting range.

Results

Results revealed that tumour necrosis factor-α (TNF-α) concentrations were inversely correlated with dynamic shooting (r=−0.646, p=0.005). In addition, a trend (r=0.415, p=0.098) was noted between TNF-α concentrations and target engagement speed (ie, time to complete the shooting protocol). BDNF concentrations were significantly correlated with the Serial Sevens Test performance (r=0.672, p=0.012).

Conclusion

The results of this investigation indicate that elevated TNF-α concentrations and lower BDNF concentrations in soldiers following intense military training were associated with decreases in marksmanship and cognitive function, respectively.

Effects of β-alanine supplementation on physical performance, cognition, endocrine function, and inflammation during a 24 h simulated military operation

Sustained military operations (SUSOPs) are associated with performance decrements and cognitive dysfunction. β-Alanine (BA) supplementation may have a role in increasing soldier resiliency by enhancing muscle-buffering capacity and reducing oxidative stress. The purpose of this study was to examine the effects of BA on physical performance, cognition, endocrine function, and inflammation during a 24 h simulated SUSOP. Nineteen males were randomized into one of two groups: BA (n = 10) or placebo (n = 9; PLA) (12 g/day) for 14 days preceding the 24 h SUSOP. Assessments were performed at 0 h (0H), 12 h (12H), and 24 h (24H) during the SUSOP. No changes in visual tracking ability, jump power, or upper-body muscular endurance were observed between groups or time points (P's > 0.05). Increases in subjective feelings of soreness and fatigue were noted at 12H compared to 0H (P < 0.05) in PLA, but not in BA. Visual reaction time for PLA was slower at 24H compared to 0H (P = 0.035), and PLA made more errors on reaction time testing at 12H compared to BA (P = 0.048), but motor reaction time was faster (P = 0.016) for PLA. Simulated litter carry and 1 km run completion times increased at 24H compared to 0H in both groups (P < 0.05), however, PLA had a longer 1 km time compared to BA at 24H (P = 0.050). Increases in inflammatory and endocrine markers were observed over the SUSOP, with no differences between groups. BA supplementation appears to maintain some aspects of cognition and physical performance during a 24 h SUSOP, with no effects on endocrine function or inflammation.

Benefits of β-hydroxy-β-methylbutyrate supplementation in trained and untrained individuals

β-Hydroxy-β-Methylbutyrate (HMB) is a metabolite of the branched-chain amino acid leucine and its ketoacid α-ketoisocaproate. HMB has been widely used as an ergogenic supplement to increase muscle strength, muscle hypertrophy and enhance recovery. The physiological mechanisms that underlie these benefits are related to HMB's ability to stimulate muscle protein synthesis and minimize muscle breakdown. Although evidence supporting the benefits of HMB supplementation is not conclusive, many of these studies have suffered from methodological flaws including different formulations, supplement duration and population studied. HMB in its free acid formulation is suggestive of having a greater potential for efficacy in both trained and untrained populations than its calcium-salt form. However, the evidence regarding HMB's role in limiting muscle degradation and increasing muscle protein synthesis has created an exciting interest in examining its efficacy among untrained individuals. Recent investigations examining intense training have demonstrated efficacy in maintaining muscle mass and attenuating the inflammatory response.

Comparison Between Bench Press Throw and Ballistic Push-up Tests to Assess Upper-Body Power in Trained Individuals

Bartolomei, S, Nigro, F, Ruggeri, S, Malagoli Lanzoni, I, Ciacci, S, Merni, F, Sadres, E, Hoffman, JR, and Semprini, G. Comparison between bench press throw and ballistic push-up tests to assess upper-body power in trained individuals. J Strength Cond Res 32(6): 1503-1510, 2018-The purpose of this study was to validate the ballistic push-up (BPU) test performed with hands on a force plate as a method to measure upper-body power. Twenty-eight experienced resistance-trained men (age = 25.4 ± 5.2 years; body mass = 78.5 ± 9.0 kg; body height = 179.6 ± 7.8 cm) performed, 2 days apart, a bench press 1 repetition maximum (1RM) test and upper-body power tests. Mean power (MP) and peak power (PP) were assessed using the bench press throw (BT) test and the BPU test performed in randomized order. The area under the force/power curve (AUC) obtained at BT was also calculated. Power expressed at BPU was estimated using a time-based prediction equation. Mean force and the participant's body weight were used to predict the bench press 1RM. Pearson product-moment correlations were used to examine relationships between the power assessment methods and between the predicted 1RM bench and the actual value. Large correlations (0.79; p < 0.001) were found between AUC and MP expressed at BPU. Large correlations were also detected between MP and PP expressed at BT and BPU (0.75; p < 0.001 and 0.74; p < 0.001, respectively). Very large correlations (0.87; p < 0.001) were found between the 1RM bench and the 1RM predicted by the BPU. Results of this study indicate that BPU represents a valid and reliable method to estimate the upper-body power in resistance-trained individuals.

Role of Endogenous and Exogenous Corticosterone on Behavioral and Cognitive Responses to Low-Pressure Blast Wave Exposure

The complex interactions and overlapping symptoms of comorbid post-traumatic stress disorder (PTSD) and mild traumatic brain injury (mTBI) induced by an explosive blast wave have become a focus of attention in recent years, making clinical distinction and effective intervention difficult. Because dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is thought to underlie trauma-related (psycho)pathology, we evaluated both the endogenous corticosterone response and the efficacy of exogenous hydrocortisone treatment provided shortly after blast exposure. We employed a controlled experimental blast-wave paradigm in which unanesthetized animals were exposed to visual, auditory, olfactory, and tactile effects of an explosive blast wave produced by exploding a thin copper wire. Endogenous corticosterone concentrations were evaluated at different time points (before, and 3 h, 5 h and 17 days) after blast exposure. Subsequently, the efficacy of exogenous hydrocortisone (25 mg/kg^-1 or 125 mg/kg^-1) injected intraperitoneally 1 h after exposure was compared with that of a similarly timed saline injection. Validated cognitive and behavioral tests were used to assess both PTSD and mTBI phenotypes on days 7-14 following the blast. Retrospective analysis revealed that animals demonstrating the PTSD phenotype exhibited a significantly blunted endogenous corticosterone response to the blast compared with all other groups. Moreover, a single 125 mg/kg^-1 dose of hydrocortisone administered 1 h after exposure significantly reduced the occurrence of the PTSD phenotype. Hydrocortisone treatment did not have a similar effect on the mTBI phenotype. Results of this study indicate that an inadequate corticosteroid response following blast exposure increases risk for PTSD phenotype, and corticosteroid treatment is a potential clinical intervention for attenuating PTSD. The differences in patterns of physiological and therapeutic response between PTSD and mTBI phenotypes lend credence to the retrospective behavioral and cognitive classification criteria we designed, and is in keeping with the assumption that mTBI and PTSD phenotypes may reflect distinct underlying biological and clinical profiles.

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.

Differential effects of speed on two-dimensional foot strike pattern during barefoot and shod running in recreationally active men

The majority of barefoot running studies have not considered speed as an influential factor on foot strike pattern. The aim of this study was to investigate differences in foot strike pattern and spatiotemporal characteristics between barefoot and shod overground running at varying speeds. We first determined maximal running speed (Vm) over 50 m in 15 recreationally active men who self-reported as habitual rearfoot strikers. Participants then completed shod and barefoot running trials at different speeds equivalent to approximately 90%, 80%, 70% and 60% of Vm. Sagittal plane two-dimensional (2D) foot-ground contact angle, ankle plantar-dorsi flexion angle, contact time, flight time, step length and step rate variables for each trial were recorded. A significant interaction effect of running speed and footwear condition (p < 0.05) on foot-ground contact angle, ankle plantar-dorsi flexion angle and contact time was observed. There was a main effect of running speed (p < 0.01) on flight time, step length and step rate. There was a main effect of footwear condition on step length (p < 0.01). Participants were more inclined to plantarflex the ankle and contact the ground with the forefoot at higher percentages of Vm, especially when running barefoot.