Innovations in the Assessment of Skeletal Muscle Health: A Glimpse into the Future.

Skeletal muscle is the largest organ system in the human body and plays critical roles in athletic performance, mobility, and disease pathogenesis. Despite growing recognition of its importance by major health organizations, significant knowledge gaps remain regarding skeletal muscle health and its crosstalk with nearly every physiological system. Relevant public health challenges like pain, injury, obesity, and sarcopenia underscore the need to accurately assess skeletal muscle health and function. Feasible, non-invasive techniques that reliably evaluate metrics including muscle pain, dynamic structure, contractility, circulatory function, body composition, and emerging biomarkers are imperative to unraveling the complexities of skeletal muscle. Our concise review highlights innovative or overlooked approaches for comprehensively assessing skeletal muscle in vivo. We summarize recent advances in leveraging dynamic ultrasound imaging, muscle echogenicity, tensiomyography, blood flow restriction protocols, molecular techniques, body composition, and pain assessments to gain novel insight into muscle physiology from cellular to whole-body perspectives. Continued development of precise, non-invasive tools to investigate skeletal muscle are critical in informing impactful discoveries in exercise and rehabilitation science.

Incidence of hydrocephalus following decompressive craniectomy for ischaemic stroke: A systematic review and meta-analysis.

OBJECTIVE: Decompressive craniectomy (DC) following malignant ischaemic stroke is a potentially life-saving procedure. Event rates of ventriculomegaly following DC performed in this setting remain poorly defined. Accordingly, we performed a systematic review to determine the incidence of hydrocephalus and the need for cerebrospinal fluid (CSF) diversion following DC for malignant stroke. METHODS: MEDLINE, EMBASE and Cochrane libraries were searched from database inception to 17 July 2021. Our search strategy consisted of "Decompressive Craniectomy", AND "Ischaemic stroke", AND "Hydrocephalus", along with synonyms. Through screening abstracts and then full texts, studies reporting on rates of ventriculomegaly following DC to treat ischaemic stroke were included for analysis. Event rates were calculated for both of these outcomes. A risk of bias assessment was performed to determine the quality of the included studies. RESULTS: From an initial 1117 articles, 12 were included following full-text screening. All were of retrospective design. The 12 included studies reported on 677 patients, with the proportion experiencing hydrocephalus/ventriculomegaly being 0.38 (95% CI: 0.24, 0.53). Ten studies incorporating 523 patients provided data on the need for permanent CSF diversion, with 0.10 (95% CI: 0.07, 0.13) requiring a shunt. The included studies were overall of high methodological quality and rigour. CONCLUSION: Though hydrocephalus is relatively common following DC in this clinical setting, only a minority of patients are deemed to require permanent CSF diversion. Clinicians should be aware of the incidence of this complication and counsel patients and families appropriately.

Time of Day Effects on Anaerobic Performance Using a Nonmotorized Treadmill.

ABSTRACT: Renziehausen, JM, Bergquist, AM, Park, J-H, Hill, EC, Wells, AJ, Stout, JR, and Fukuda, DH. Time of day effects on anaerobic performance using a nonmotorized treadmill. J Strength Cond Res 37(10): 2002-2007, 2023-The purpose of this study was to determine the effects of time of day on performance during a maximal effort sprinting assessment (30nmt) and determine potential differences based on chronotype and sex. Twenty-six recreationally active men (n = 12) and women (n = 14) between the ages of 18 and 35 years old (21.5 ± 2.4 years) completed the 30nmt at 9:00 am, 2:00 pm, and 7:00 pm in a randomized order over a 24-hour period. Resting heart rate and temperature assessments were taken at each visit. A dietary recall and the Morningness-Eveningness Questionnaire were used to assess kilocalories (kcals) and chronotype, respectively. Two-way (time x sex) repeated measures analyses of variance were conducted to determine differences in peak/mean power, peak/mean velocity, distance, resting heart rate, temperature, and kcals at each time point. Paired sample t tests were used to assess peak and nadir of each performance variable. A significance level was set at p < 0.05. There was a significant main effect for temperature (p < 0.001), resting heart rate (p = 0.007), and pre-exercise caloric intake (p = 0.021) throughout the day. No significant main effects for time were found for peak power (p = 0.766), mean power (p = 0.094), peak velocity (p = 0.497), mean velocity (p = 0.193), or distance (p = 0.262). There were no significant time × sex interactions for any dependent performance variables (p > 0.05). Significant differences were shown between the peak and nadir of each performance variable (p < 0.001). There were no significant differences in performance during maximal effort anaerobic assessments shown throughout the day; however, peak/nadir of performance times may be individualized and differ between morning types and intermediate types.

Evaluating the effects of PeakATP® supplementation on visuomotor reaction time and cognitive function following high-intensity sprint exercise.

The purpose of this study was to examine the effects of 14-days adenosine 5'-triphosphate (ATP) supplementation (PeakATP®) on reaction time (RT), multiple object tracking speed (MOT), mood and cognition. Twenty adults (22.3 ± 4.4 yrs., 169.9 ± 9.5 cm, 78.7 ± 14.6 kg) completed two experimental trials in a double-blind, counter-balanced, crossover design. Subjects were randomized to either PeakATP® (400 mg) or placebo (PLA) and supplemented for 14-days prior to each trial. During each trial, subjects completed a three-minute all-out test on a cycle ergometer (3MT), with measures of visuomotor RT [Dynavision D2 Proactive (Mode A) and Reactive (Mode B) tasks], MOT (Neurotracker), mood (Profile of Mood States Questionnaire; POMS) and cognition (Automated Neuropsychological Assessment Metrics; ANAM) occurring before (PRE), immediately post (IP) and 60 min post-3MT (60P). Subjects ingested an acute dose of the assigned supplement 30 min prior to completing PRE assessments for each trial. Trials were separated by a 14-day washout period. PeakATP® significantly attenuated declines in hits (p = 0.006, ηp2 = 0.235) and average RT (AvgRT, p = 0.006, ηp2 = 0.236) in Mode A, significantly improved AvgRT (p = 0.039, ηp2 = 0.174) in Mode B, and significantly reduced the total number of misses (p = 0.005, ηp2 = 0.343) in Mode B. No differences between treatments were noted for MOT, POMS or ANAM variables. In conclusion, these results indicate that PeakATP® maintains proactive RT and improves reactive RT following high-intensity sprint exercise suggesting that supplemental ATP may mitigate exercise induced cognitive dysfunction.

Increased distance or time from a major trauma centre in South Australia is not associated with worse outcomes after moderate to severe traumatic brain injury.

OBJECTIVE: Considerations in traumatic brain injury (TBI) management include time to critical interventions and neurosurgical care, which can be influenced by the geographical location of injury. In Australia, these distances can be vast with varying degrees of first-responder experience. The present study aimed to evaluate the association that distance and/or time to a major trauma centre (MTC) had on patient outcomes with moderate to severe TBI. METHODS: A retrospective cohort study was conducted using data from the Royal Adelaide Hospital's (RAH) Trauma Registry over a 3-year period (1 January 2018 to 31 December 2020). All patients with a moderate to severe TBI (Glasgow Coma Scale [GCS] ≤13 and abbreviated injury score head of ≥2) were included. The association of distance and time to the RAH and patient outcomes were compared by calculating the odds ratio utilising a logistic regression model. RESULTS: A total of 378 patients were identified; of these, 226 met inclusion criteria and comprised our study cohort. Most patients were male (79%), injured in a major city (55%), with median age of 38 years old and median injury severity score (ISS) of 25. After controlling for age, ISS, ED GCS on arrival and pre-MTC intubation, increasing distance or time from injury site to the RAH was not shown to be associated with mortality or discharge destination in any of the models investigated. CONCLUSION: Our analysis revealed that increasing distance or time from injury site to a MTC for patients with moderate to severe TBI was not significantly associated with adverse patient outcomes.

Imaging evaluation of a proposed 3D generative model for MRI to CT translation in the lumbar spine.

BACKGROUND CONTEXT: A computed tomography (CT) and magnetic resonance imaging (MRI) are used routinely in the radiologic evaluation and surgical planning of patients with lumbar spine pathology, with the modalities being complimentary. We have developed a deep learning algorithm which can produce 3D lumbar spine CT images from MRI data alone. This has the potential to reduce radiation to the patient as well as burden on the health care system. PURPOSE: The purpose of this study is to evaluate the accuracy of the synthetic lumbar spine CT images produced using our deep learning model. STUDY DESIGN: A training set of 400 unpaired CTs and 400 unpaired MRI scans of the lumbar spine was used to train a supervised 3D cycle-Gan model. Evaluators performed a set of clinically relevant measurements on 20 matched synthetic CTs and true CTs. These measurements were then compared to assess the accuracy of the synthetic CTs. PATIENT SAMPLE: The evaluation data set consisted of 20 patients who had CT and MRI scans performed within a 30-day period of each other. All patient data was deidentified. Notable exclusions included artefact from patient motion, metallic implants or any intervention performed in the 30 day intervening period. OUTCOME MEASURES: The outcome measured was the mean difference in measurements performed by the group of evaluators between real CT and synthetic CTs in terms of absolute and relative error. METHODS: Data from the 20 MRI scans was supplied to our deep learning model which produced 20 "synthetic CT" scans. This formed the evaluation data set. Four clinical evaluators consisting of neurosurgeons and radiologists performed a set of 24 clinically relevant measurements on matched synthetic CT and true CTs in 20 patients. A test set of measurements were performed prior to commencing data collection to identify any significant interobserver variation in measurement technique. RESULTS: The measurements performed in the sagittal plane were all within 10% relative error with the majority within 5% relative error. The pedicle measurements performed in the axial plane were considerably less accurate with a relative error of up to 34%. CONCLUSIONS: The computer generated synthetic CTs demonstrated a high level of accuracy for the measurements performed in-plane to the original MRIs used for synthesis. The measurements performed on the axial reconstructed images were less accurate, attributable to the images being synthesized from nonvolumetric routine sagittal T1-weighted MRI sequences. It is hypothesized that if axial sequences or volumetric data were input into the algorithm these measurements would have improved accuracy.

The Effects of Two Weeks of Oral PeakATP® Supplementation on Performance during a Three-Minute All out Test.

Exogenous ATP has been shown to increase total weight lifted during resistance training interventions and attenuate fatigue during repeated Wingate assessments. However, the influence of exogenous ATP on single bout maximal effort performance has yet to be examined. The purpose of this study was to investigate the effects of PeakATP® supplementation on performance during a 3-min all-out test (3MT). Twenty adults (22.3 ± 4.4 years, 169.9 ± 9.5 cm, 78.7 ± 14.6 kg) completed two identical 3MT protocols in a double-blind, counter-balanced, crossover design. Participants were randomized to either PeakATP® (400 mg·day-1) or placebo (PLA) treatments and consumed their assigned supplement for 14 days and ingested an acute dose 30 min before each 3MT. A 14-day wash-out period was completed between each supplementation period and subsequent 3MT. Peak power, time to peak power, work above end power, end power, and fatigue index were assessed during each 3MT. Dependent t-tests and Hedge's g effect sizes were used to assess differences between treatments. No significant differences were observed between treatments for 3MT performance (p > 0.05). These findings indicate that 3MT performance was not significantly impacted by PeakATP® supplementation. This may be due in part to the continuous nature of the 3MT as disodium ATP has been shown to be beneficial for repeated bout activities.

Carbohydrate-Protein drink is effective for restoring endurance capacity in masters class athletes after a two-Hour recovery.

BACKGROUND: Carbohydrate (CHO) and carbohydrate-protein co-ingestion (CHO-P) have been shown to be equally effective for enhancing glycogen resynthesis and subsequent same-day performance when CHO intake is suboptimal (≤0.8 g/kg). Few studies have specifically examined the effect of isocaloric CHO vs CHO-P consumption on subsequent high-intensity aerobic performance with limited time to recover (≤2 hours) in masters class endurance athletes. METHODS: This was a randomized, double-blind between-subject design. Twenty-two male masters class endurance athletes (age 49.1 ± 6.9 years; height 175.8 ± 4.8 cm; body mass 80.7 ± 8.6 kg; body fat (%) 19.1 ± 5.8; VO2peak 48.6 ± 6.7 ml·kg·min-1) were assigned to consume one of three beverages during a 2-hour recovery period: Placebo (PLA; electrolytes and water), CHO (1.2 g/kg bm), or CHO-P (0.8 g/kg bm CHO + 0.4 g/kg bm PRO). All beverages were standardized to one liter (~32 oz.) of total fluid volume regardless of the treatment group. During Visit #1, participants completed graded exercise testing on a cycle ergometer to determine VO2peak and peak power output (PPO, watts). Visit #2 consisted of familiarization with the high-intensity protocol including 5 × 4 min intervals at 70-80% of PPO with 2 min of active recovery at 50 W, followed by a time to exhaustion (TTE) test at 90% PPO. During Visit#3, the same high-intensity interval protocol with TTE was conducted pre-and post-beverage consumption. RESULTS: A one-way ANCOVA indicated a significant difference among the group means for the posttest TTE (F2,18 = 6.702, p = .007, ƞ2 = .427) values after adjusting for the pretest differences. TTE performance in the second exercise bout improved for the CHO (295.48 ± 24.90) and CHO-P (255.08 ± 25.07 sec) groups. The water and electrolyte solution was not effective in restoring TTE performance in the PLA group (171.13 ± 23.71 sec). CONCLUSIONS: Both CHO and CHO-P effectively promoted an increase in TTE performance with limited time to recover in this sample of masters class endurance athletes. Water and electrolytes alone were not effective for restoring endurance capacity during the second bout of exhaustive exercise.

Effects of a Multi-Ingredient Oral Supplement on Multiple Object Tracking, Reaction Time, and Reactive Agility.

Background: The demands of typical daily activities require a constant level of alertness and attention. Multi-ingredient, caffeine-containing supplements have been shown to improve measures of cognitive performance. As many of these supplements become readily available, efficacy of each should be evaluated. Therefore, the purpose of this study is to examine the effects of the 4D dietary supplement on cognition, reaction time, and reactive agility. Methods: Seventeen healthy males (n = 8) and females (n = 9) between the ages of 18-40 years old (22.8 ± 2.9 years; 167.3 ± 9.6 cm; 65.4 ± 10.9 kg) participated in this double-blind, randomized crossover study. Participants completed three baseline reaction time assessments on the Dynavision and one baseline multiple object tracking assessment on the Neurotracker. Participants then consumed the oral multi-ingredient supplement containing 150 mg of caffeine or non-caffeinated placebo, mixed with 24 ounces of water, and rested for 45 minutes. Following the rest period, participants completed an additional three reaction time assessments and one multiple object tracking (MOT) assessment, as well as 6-12 trials of the Y-reactive agility test. Repeated measures ANOVAs were used to evaluate YRA performance and change values for Dynavision RT, Dynavision score, and MOT speed with either 4D dietary supplement or placebo. Results: A significant time × supplement interaction was shown for MOT speed (p = .040, d = .543). Change scores in MOT speed were significantly different from zero following 4D (mean: 0.224 au; 95% confidence interval: 0.050 to 0.398 au) but not placebo supplementation (mean: -0.046 au; 95% confidence interval: -0.220 to 0.127 au). No time × supplement interaction was shown for Dynavision RT (p = .056, d = -.499) or Dynavision score (p = .093, d = .434). No differences were shown for YRA scores following supplementation for the right side (p = .241, d = -.295) or left side (p = .378, d = -.220). Conclusion: The 4D dietary supplement appears to improve measures of cognition, specifically attention/spatial awareness, but not reaction time or reactive agility. Future research should examine the effects of this supplement with a larger, less heterogeneous sample and/or in conjunction with an exercise intervention.

Symptomatic cerebral vasospasm following posterior fossa hemangioblastoma resection: illustrative case.

BACKGROUND: Symptomatic cerebral vasospasm following posterior fossa intra-axial tumor resection is a rare phenomenon with only seven cases previously reported in the literature. The condition appears distinct to vasospasm following supratentorial tumor resection and extra-axial tumor resection of the posterior fossa. It shares, however, similarities with vasospasm following aneurysmal subarachnoid hemorrhage. OBSERVATIONS: The authors describe their experience with a 23-year-old female who developed delayed symptomatic vasospasm following resection of a left parapontine cerebellar hemangioblastoma. Tumor resection was complicated by rupture of a fragile arterialized vein, resulting in significant hemorrhage. The patient developed several episodes of focal and variably reversible neurological deficit. These clinical signs corresponded with angiographically confirmed vasospasm, which responded to standard therapies for vasospasm post aneurysmal subarachnoid hemorrhage. LESSONS: This case and literature review highlight that symptomatic vasospasm is a rare, potentially highly morbid complication of posterior fossa intra-axial tumor resection. This phenomenon may be related to significant intraoperative or postoperative hemorrhage. Postoperative radiological findings such as high risk modified Fisher scale hemorrhage could alert clinicians to this condition.

High-Risk Environmental Conditions Attenuates Performance Efficiency Index in NCAA DI Female Soccer Players.

The purpose of this study was to evaluate the effects of environmental conditions on running performance and performance efficiency index (Effindex). Performance data recorded using Polar Team Pro sensors from eight collegiate female soccer players in nine matches were analyzed during the 2019 competitive season. Effindex and running performance, including total distance covered (TDREL) and distance covered in five speed thresholds relative to minutes played, were examined for indications of fatigue with respect to environmental conditions, including ambient temperature and relative humidity. Matches were separated into three groups based on environmental conditions: Low-Risk (n = 2 matches), Moderate-Risk (n = 3 matches), or High-Risk (n = 4 matches). Speed thresholds were grouped as follows: walking (WALKREL), jogging (JOGREL), low-speed running (LSRREL), high-speed running (HSRREL), and sprinting (SPRINTREL). A significant effect was observed for TDREL in all environmental conditions (η2 = 0.614). TDREL was significantly lower in the High-Risk (p = 0.002; 95.32 ± 12.04 m/min) and Moderate-Risk conditions (p = 0.004; 94.85 ± 9.94 m/min) when compared to Low-Risk (105.61 ± 9.95 m/min). WALKREL (p = 0.005), JOGREL (p = 0.005) LSRREL (p = 0.001), HSRREL (p = 0.035), SPRINTREL (p = 0.017), and Effindex (p = 0.0004) were significantly greater in Low-Risk conditions when compared to Moderate-Risk conditions. WALKREL (p = 0.005), HSRREL (p = 0.029), SPRINTREL (p = 0.005), and Effindex (p = 0.0004) were significantly greater in Low-Risk conditions when compared to High-Risk conditions. High-Risk environmental conditions may result in adverse performance in female collegiate soccer players.

Test-Retest Reliability, Training, and Detraining Effects Associated With the Dynavision D2™ Mode A Visuomotor Reaction Time Test.

CONTEXT: The Dynavision D2™ Mode A test (ModeA) is a 1-minute reaction time (RT) test commonly used in sports science research and clinical rehabilitation. However, there is limited data regarding the effect of repeated testing (ie, training) or subsequent periods of no testing (ie, detraining) on test-retest reliability and RT performance. Therefore, the purpose of this study was to examine the test-retest reliability, training, and detraining effects associated with the D2™ ModeA test. DESIGN: Repeated measures/reliability. METHODS: Twenty-four recreationally active men and women completed 15 training sessions consisting of 2 ModeA tests per session (30 tests). The participants were then randomized to either 1 or 2 weeks of detraining prior to completing 15 retraining sessions (30 tests). The training and retraining periods were separated into 10 blocks for analysis (3 tests per block). The number of hits (hits) and the average RT per hit (AvgRT) within each block were used to determine RT performance. Intraclass correlation coefficients, SEM, and minimum difference were used to determine reliability. Repeated-measures analysis of variance/analysis of covariance were used to determine training and detraining effects, respectively. RESULTS: The ModeA variables demonstrated excellent test-retest reliability (intraclass correlation coefficient2,3 > .93). Significant improvements in hits and AvgRT were noted within training blocks 1 to 5 (P < .05). No further improvements in RT performance were noted between training blocks 6 through 10. There was no effect of detraining period on RT. The RT performance was not different between blocks during retraining. CONCLUSIONS: It appears that 15 tests are necessary to overcome the training effect and establish reliable baseline performance for the ModeA test. Detraining for 1 to 2 weeks did not impact RT performance. The authors recommend that investigators and clinicians utilize the average of 3 tests when assessing RT performance using the D2 ModeA test.

Emergency Neurosurgery Performed by General Surgeons: A Systematic Review.

BACKGROUND: In under-resourced settings, general surgeons may be called upon to perform emergency operations within other specialties. Accordingly, we aimed to characterise patient outcomes after emergency neurosurgery performed by a general surgeon or general surgery trainee. METHODS: PubMed, Embase and the Cochrane Library were searched to 30 May 2021 for observational studies reporting outcomes after emergency neurosurgery performed by a general surgeon. Study screening, data extraction, and risk of bias using the Downs and Black checklist were performed in duplicate. Data on setting, operation undertaken, mortality rates and complications were extracted. Meta-analysis was planned but not possible due to heterogeneity. This study is registered with PROSPERO, CRD42021258097. RESULTS: From 632 records, 14 retrospective observational studies were included, covering a total sample of 1,988 operations. Four studies were from Australia, and the remaining 10 were, respectively, from 10 other countries. Most common operations performed were decompressive surgery with burr holes or craniectomy for head trauma and insertion of intracranial pressure monitors. Rural hospitals were the most common settings. Mortality rates for procedures performed by general surgeons at latest follow-up were heterogenous, ranging from 5% for evacuation of chronic subdural haematoma in Kenya to 81% in head injured patients in a Hong Kong study. CONCLUSIONS: This is the first systematic review that synthesises the literature to characterise patient outcomes after neurosurgical operations performed by a general surgeon. Findings from this study may benefit global surgery performed in rural, remote, military or humanitarian settings.

Absence of small study effects in neurosurgical meta-analyses: A meta-epidemiological study.

BACKGROUND: Small studies are prone to lower methodological quality and publication bias, and are more likely to report greater beneficial effects. A meta-epidemiological study was undertaken to investigate and quantify the impact of small study effects on meta-analyses in the neurosurgical literature. METHODS: A PubMed search was used to procure meta-analyses from Journal of Neurosurgery, Neurosurgery, Spine, Acta Neurochirurgica and Journal of Neurotrauma. Outcome data were extracted from meta-analyses the effect of study size was estimated by calculating the ratio of odds ratios (RORs) between small and large studies. RESULTS: 16 meta-analyses of 229 primary studies and 90,629 patients were included. All but two included pooled outcomes were significantly different from 1. On average small studies did not demonstrate greater beneficial effects, with an estimated pooled ROR of 1.32 (95% CI, 0.89 to 1.75). Stratification by meta-analysis effect size and heterogeneity yielded similar findings. CONCLUSIONS: The absence of small study effects in meta-analyses of neurosurgical studies may reflect widespread poor quality of the neurosurgical literature affecting both large and small studies, rather than an absence of publication bias.

Tensiomyographic Responses to Warm-Up Protocols in Collegiate Male Soccer Athletes.

The mechanical properties of knee flexors and extensors in 15 collegiate male soccer players following different warm-up protocols [small-sided games (SSG), dynamic (DYN), and plyometric (PLY)] were evaluated. Tensiomyography (TMG) was used to assess contraction time (Tc), delay time (Td) and maximal displacement (Dm) of the rectus femoris (RF) and biceps femoris (BF) of both legs before and after each warm-up, while countermovement jump height variables, 20 m sprint, t-test and sit-and-reach were measured following the warm-ups. TMG was analyzed using a three-way [condition × time × leg] ANOVA, while performance variables were analyzed with a repeated measures ANOVA. Main effects of time were observed for BF-Tc (p = 0.035), RF-Td (p < 0.001), and BF-Td, (p = 0.008), and a main effect of condition was seen for RF-Tc (p = 0.038). Moreover, participants' 20 m sprint improved following SSG (p = 0.021) compared to DYN and PLY. Sit-and-reach was greater following PLY (p = 0.021). No significant interactions were noted for the measured TMG variables. Warm-up-specific improvements were demonstrated in sprint speed and flexibility following SSG and PLY, respectively. The present study revealed changes in certain TMG measures following the warm-ups that suggest enhanced response of lower leg muscles regardless of specific activities used.

Effects of High-Dose, Short-Duration ß-Alanine Supplementation on Cognitive Function, Mood, and Circulating Brain-Derived Neurotropic Factor (BDNF) in Recreationally-Active Males Before Simulated Military Operational Stress.

Introduction: ß-alanine (BA) supplementation may improve cognition and mitigate symptoms of anxiety and depression associated with aging, neurological disorders, and physical exertion, which has been attributed to increases in brain carnosine and/or brain-derived neurotropic factor (BDNF). BA also provides beneficial effects on cognition, mood, and physical performance during military operations; however, whether BA can attenuate mood disruptions and cognitive dysfunction associated with the anticipatory stress prior to simulated military operations is unknown.Purpose: The present study examined the effects of 14 days of BA (12 g·day-1) supplementation on cognitive function, mood, and circulating BDNF concentrations in recreationally-active, healthy males with limited inflammation and oxidative stress prior to a 24h simulated military operation.Methods: Participants were randomized into BA (n = 10) or placebo (n = 9; PL) for 14 days. Cognitive function, mood, and circulating BDNF were assessed before (PRE) and after (POST) supplementation. Cognition was assessed via multiple object tracking (Neurotracker™), visuomotor reaction time (Dynavision™), mathematical processing (Serial Subtraction Test), and neuropsychological assessments (ANAM™). Mood was assessed using the Profile of Mood States (POMS) questionnaire. After POST testing, subjects underwent a 24h simulated military operation.Results: No change in measures of cognitive function or BDNF concentrations were observed (p > 0.05). However, BA experienced significant reductions (p = 0.046) in subjective feelings of depression, while PL experienced significant reductions (p = 0.021) in feelings of vigor from PRE to POST.Conclusions: High-dose, short-duration BA supplementation does not appear to affect cognitive function or circulating BDNF, but may mitigate the onset of negative mood states in healthy, recreationally-active males prior to a simulated military operation.

Influence of muscle depth and thickness on ultrasound echo intensity of the vastus lateralis.

BACKGROUND: Ultrasonography is used to evaluate muscle quality (i.e. echo intensity [EI]), but an attenuation of ultrasound waves occurs in deeper tissues, potentially affecting these measures. PURPOSE: To determine whether muscle thickness (MT) affects EI and if EI varies between the superficial and deep portions of the muscle. MATERIALS AND METHODS: MT, EI, subcutaneous adipose tissue thickness (SAT), tissue depth (DISDEEP), and EI of the overall (EIFULL) as well as deep (EIDEEP) and superficial (EISUPF) portions of the vastus lateralis (VL) were assessed in 33 resistance-trained males using ultrasonography. The difference (EIDIFF) between EISUPF and EIDEEP was calculated. Mean differences between EIFULL, EISUPF, and EIDEEP were analyzed using a repeated-measures analysis of variance (ANOVA). Relationships between measures of muscle depth/ thickness and EI were examined using Pearson's r. RESULTS: EISUPF was greater than EIDEEP (P < 0.001) and EIFULL (P < 0.001). MT was negatively correlated with EIFULL (P < 0.001) and positively correlated with EIDIFF (P < 0.001). SAT was not correlated with any EI measure, but DISDEEP was positively correlated with EIDIFF (P < 0.001). CONCLUSION: EI of the VL is heterogeneous, as the deeper portion produces lower values than the superficial portion. Thicker muscles present lower EI but have greater discrepancies in EI between the superficial and deep portions. Although SAT was not correlated with EI, DISDEEP was related to EIDIFF, demonstrating that the combination of MT and SAT should be considered when evaluating muscle quality. Future research is necessary to determine if changes in EI following resistance training are driven by increases in MT.

Effect of ß-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 ß-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 (ß = -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.

Heart Rate Variability Behavior during Exercise and Short-Term Recovery Following Energy Drink Consumption in Men and Women.

This study examined the cardiac autonomic responses, as measured by heart rate variability (HRV), during cycling exercise and short-term rest after energy drink consumption. Seventeen participants (seven males and 10 females; age: 22.8 ± 3.5 years; BMI: 24.3 ± 3.3 kg/m2) completed this double-blind, placebo-controlled, counterbalanced crossover design study. Participants received an energy drink formula containing 140 mg of caffeine and a placebo in a randomized order before completing a 10-min steady-state warm up (WUP) and a graded exercise test to exhaustion (GXT) followed by a 15-min short-term rest (STR) period. Heartbeat intervals were recorded using a heart rate monitor. Data were divided into WUP, GXT, and STR phases, and HRV parameters were averaged within each phase. Additionally, root mean square of the standard deviation of R-R intervals (RMSSD) during GXT was analyzed to determine the HRV threshold. Separate two-way (sex (male vs. female) x drink (energy drink vs. placebo)) repeated measures ANOVA were utilized. Significant increases in high frequency (HF) and RMSSD were shown during WUP after energy drink consumption, while interactions between drink and sex were observed for HRV threshold parameters (initial RMSSD and rate of RMSSD decline). No significant differences were noted during STR. Energy drink consumption may influence cardiac autonomic responses during low-intensity exercise, and sex-based differences in response to graded exercise to exhaustion may exist.