Is the OUTPUT Sports Unit Reliable and Valid When Estimating Back Squat and Bench Press Concentric Velocity?

ABSTRACT: Merrigan, JJ and Martin, JR. Is the OUTPUT sports unit reliable and valid when estimating back squat and bench press concentric velocity? J Strength Cond Res 36(8): 2069-2076, 2022-This study evaluated the reliability and concurrent validity of the OUTPUT sports inertial unit to measure concentric velocity of free-weight back squat and bench press exercises. Eleven men and women performed back squat and bench press 1 repetition maximum (1RM) testing. One week later, subjects performed 3 repetitions of each exercise with 35, 45, 55, 65, 75, and 85% 1RM (18 total repetitions). The OUTPUT and 4 cable extension transducers (criterion) simultaneously recorded the mean and peak velocity. The OUTPUT had acceptable reliability for all loads except 85% 1RM for back squat and bench press (intraclass correlation coefficient = 0.72-0.96, coefficient of variation = 0.03-0.12). High systematic biases existed for the mean and peak velocity for the back squat and bench press, according to Bland-Altman plot's wide limits of agreement and ordinary least products regressions. According to Bland-Altman plots, OUTPUT tended to overestimate bench press velocity and overestimate back squat velocity at slower velocities. Least products regression analyses determined proportional bias existed for the mean and peak velocity of the back squat and peak velocity of the bench press. In conclusion, researchers and practitioners are advised not to compare velocity estimates of the OUTPUT unit with criterion devices because these methods cannot be used interchangeably. However, because of the demonstrated reliability when estimating the mean and peak velocity, strength and conditioning practitioners may find the OUTPUT unit valuable for monitoring performance of the back squat and bench press exercises. Yet, caution should be taken when evaluating loads ≥85% 1RM.

Selective Formation of Porous Pt Nanorods for Highly Electrochemically Efficient Neural Electrode Interfaces.

The enhanced electrochemical activity of nanostructured materials is readily exploited in energy devices, but their utility in scalable and human-compatible implantable neural interfaces can significantly advance the performance of clinical and research electrodes. We utilize low-temperature selective dealloying to develop scalable and biocompatible one-dimensional platinum nanorod (PtNR) arrays that exhibit superb electrochemical properties at various length scales, stability, and biocompatibility for high performance neurotechnologies. PtNR arrays record brain activity with cellular resolution from the cortical surfaces in birds and nonhuman primates. Significantly, strong modulation of surface recorded single unit activity by auditory stimuli is demonstrated in European Starling birds as well as the modulation of local field potentials in the visual cortex by light stimuli in a nonhuman primate and responses to electrical stimulation in mice. PtNRs record behaviorally and physiologically relevant neuronal dynamics from the surface of the brain with high spatiotemporal resolution, which paves the way for less invasive brain-machine interfaces.

What do Firefighting Ability Tests Tell Us About Firefighter Physical Fitness? A Systematic Review of the Current Evidence.

Fyock-Martin, MB, Erickson, EK, Hautz, AH, Sell, KM, Turnbaugh, BL, Caswell, SV, and Martin, JR. What do firefighting ability tests tell us about firefighter physical fitness? A systematic review of the current evidence. J Strength Cond Res 34(7): 2093-2103, 2020-The firefighting profession is a physiologically demanding occupation. Currently, sudden cardiac deaths account for 40-50% of firefighter job-related deaths, for which, inadequate aerobic fitness (AF) and obesity are established as risk factors. Departments have instituted firefighting physical ability tests (FPATs) as a method of quantifying readiness for occupational-related demands. A systematic review of the current literature examining the correlation between field fitness test performance and FPAT completion times was performed. The search identified 5 studies that met the eligibility criteria. The total number of subjects in the 5 studies was 265 (259 men and 6 women), including 200 professional firefighters (75.5%), 40 volunteer (15.1%), 20 officers (7.5%), and 5 recruits (1.9%). Upper-body strength (UBs) and upper-body endurance (UBe) had the strongest correlation to FPATs (r = -0.31 to -0.66; R = 0.10 to 0.44 and r = -0.27 to -0.61; R = 0.07 to 0.37; p < 0.05, respectively). Two studies suggested that AF has a weak-to-moderate relationship with FPATs (r = 0.38 and r = -0.62). Two studies showed that anaerobic capacity had weak-to-strong correlations with FPATs (r = -0.40 and r = 0.79; R = 0.16 to 0.62; p < 0.05). No studies found a statistically significant correlation between lower-body strength and FPAT performance. Further research is needed to better understand the role of field-based fitness test results on FPAT performance. An annual department-driven multicomponent fitness assessment measuring UBs, UBe, anaerobic capacity, and AF is recommended based on the evidence reviewed.

Immunosuppressive mechanisms for stem cell transplant survival in spinal cord injury.

Spinal cord injury (SCI) has been associated with a dismal prognosis-recovery is not expected, and the most standard interventions have been temporizing measures that do little to mitigate the extent of damage. While advances in surgical and medical techniques have certainly improved this outlook, limitations in functional recovery continue to impede clinically significant improvements. These limitations are dependent on evolving immunological mechanisms that shape the cellular environment at the site of SCI. In this review, we examine these mechanisms, identify relevant cellular components, and discuss emerging treatments in stem cell grafts and adjuvant immunosuppressants that target these pathways. As the field advances, we expect that stem cell grafts and these adjuvant treatments will significantly shift therapeutic approaches to acute SCI with the potential for more promising outcomes.

Effect of Direct Whole-Body Vibration on Upper-Body Muscular Power in Recreational, Resistance-Trained Men.

Jones, MT, Martin, JR, Jagim, AR, and Oliver, JM. Effect of direct whole-body vibration on upper-body muscular power in recreational, resistance-trained men. J Strength Cond Res 31(5): 1371-1377, 2017-To determine the acute effect of whole-body vibration (WBV) on upper-body power, 15 men (mean ± SD; age 21.5 ± 2.3 years; height 173.1 ± 6.5 cm; and weight 77.2 ± 13.8 kg) with ≥1-year resistance training experience and a bench press (BP): body mass ratio ≥1.25 participated in a repeated-measures crossover design. Session 1 included body composition ([Bod Pod] 15.76 ± 6.7% body fat), 3 repetition maximum BP, and familiarization with: seated medicine ball throw (SMBT), plyometric push-up (PPU) on a force plate, and vertical WBV platform. Sessions 2-5 were randomly ordered across condition and test, separated by 24 hours, and consisted of a warm-up followed by 4 × 30-second push-up holds (2 × elbows at 90° and 2 × arms extended) performed on the vibration platform with WBV (frequency: 30 Hz, amplitude: 2-4 mm, 1:1 work: relief ratio) or no WBV. Seated medicine ball throw and PPU were tested immediately, 1, 5, and 10 minutes post. Standardized magnitude-based inferences were used to define outcomes. A likely positive effect of WBV was observed for SMBT at 10 minutes post. A likely negative effect of WBV resulted at 1 minute in time-to-peak force. A possibly positive effect was observed 10 minutes post. A possibly negative effect was observed 10 minutes post for peak power, and a likely negative effect of WBV was observed on time-to-peak power immediate post. Incorporating a 10-minute rest period is recommended when implementing power exercises after upper-body static-hold exercises during WBV exposure.

Physical fitness profile of a large urban fire department: Exploring age and rank dynamics.

BACKGROUND: Firefighter physical fitness (PF) plays a crucial role in mitigating health issues and supporting occupational performance. The influence of rank on firefighter PF remains understudied and previous research is often limited by small sample sizes of firefighters volunteering for research studies, potentially biasing results towards fitter firefighters not representative of entire departments. OBJECTIVE: To examine the PF profile of firefighters in a large urban fire department and the influence of age and rank on PF. METHODS: Data, including muscular fitness, estimated aerobic capacity (VO2max), and body fat percentage (BF%) measures from 1361 firefighters (90% male; age: 37.4±10.1yrs; 60 recruits, 973 firefighters, 290 lieutenants/captains, 38 chiefs) were analyzed. Correlation and ANCOVAs were conducted to examine the impact of rank on PF while controlling for age. Score distributions were scrutinized to profile the PF of the department. RESULTS: Age was negatively associated with pull-ups (r = - 0.39), sit-ups (r = - 0.39), and push-ups (r = - 0.32), but positively associated with relative VO2max (r = 0.17) and BF% (r = 0.39). Rank had a statistically significant, but trivial effect size, on pull-ups (p = 0.028, η2 = 0.007) and sit-ups (p = 0.034, η2 = 0.005). Firefighters with lower PF levels were older, had higher BF%, lower fat-free mass, and were a greater proportion of females. CONCLUSIONS: Firefighters exhibited diverse levels of PF. Age, not rank, appeared to influence firefighters' PF. The findings that firefighters who were older, female, with poorer body composition are more likely to have lower PF levels highlights the need for individualized PF training to enhance occupational performance and health across the fire department.

Flexible, scalable, high channel count stereo-electrode for recording in the human brain.

Over the past decade, stereotactically placed electrodes have become the gold standard for deep brain recording and stimulation for a wide variety of neurological and psychiatric diseases. Current electrodes, however, are limited in their spatial resolution and ability to record from small populations of neurons, let alone individual neurons. Here, we report on an innovative, customizable, monolithically integrated human-grade flexible depth electrode capable of recording from up to 128 channels and able to record at a depth of 10 cm in brain tissue. This thin, stylet-guided depth electrode is capable of recording local field potentials and single unit neuronal activity (action potentials), validated across species. This device represents an advance in manufacturing and design approaches which extends the capabilities of a mainstay technology in clinical neurology.

Comparison of interfinger connection matrix computation techniques.

A hypothesis was proposed that the central nervous system controls force production by the fingers through hypothetical neural commands. The neural commands are scaled between values of 0 to 1, indicating no intentional force production or maximal voluntary contraction (MVC) force production, respectively. A matrix of interfinger connections transforms neural commands into finger forces. Two methods have been proposed to compute the interfinger connection matrix. The first method uses only single finger MVC trials and multiplies the interfinger connection matrix by a gain factor. The second method uses a neural network model based on experimental data. The performance of the two methods was compared on the MVC data and on a data set of submaximal forces, collected over a range of total forces and moments of force. The methods were compared in terms of (1) ability to predict finger forces, (2) accuracy of neural command reconstruction, and (3) preserved planarity of force data for submaximal force production task. Both methods did a reasonable job of predicting the total force in multifinger MVC trials; however, the neural network model performed better in regards to all other criteria. Overall, the results indicate that for modeling multifinger interaction the neural network method is preferable.

Common law enforcement load carriage systems have limited acute effects on postural stability and muscle activity.

Law enforcement officers are inherently at a high risk of injury and the loads they must carry during their occupational duties further increase their injury risk. It is unknown how different methods of carrying a law enforcement officer's load influence factors related to injury risk. This study assessed the effects of common law enforcement load carriage systems on muscular activity and postural stability while standing. Twenty-four participants performed single and dual-task (i.e. concurrent performance of cognitive tasks) standing while wearing a duty belt, tactical vest, and no load. The postural stability and muscle activity were measured and effects of condition and task examined. Dual task standing decreased postural stability and increased muscular activity. The belt and vest (7.2 kg each) increased muscle activity compared to control for the right abdominals, low back, right thigh. The duty belt resulted in less muscle activity in the right abdominals but more muscle activity in the left multifidus compared to the control. The findings indicate that common law enforcement load carriage systems increase muscular activity but do not affect postural stability. However, the lack of differences between the duty belt and tactical vest did not provide clear support for one load carriage system versus the other.

Effect of the Law Enforcement Duty Belt on Muscle Activation during Hip Hinging Movements in Young, Healthy Adults.

Sixty percent of all law enforcement officers (LEOs) experience low back pain (LBP), with the LEO duty belt (LEODB) commonly reported to be a contributing factor. The primary purpose of the study was to investigate the LEODB's effect on muscular activity and compare it to a tactical vest, which is a commonly used alternative to an LEODB. In total, 24 participants (13 male, 11 female; mass, 73.0 ± 11.1 kg; height, 169.0 ± 10.0 cm; age, 24.0 ± 5.8 years) completed a progressive series of hip hinge tasks in a single testing session. All participants completed four conditions (no belt, leather belt, nylon belt, and weight VEST) in a randomized order. Surface electromyography (sEMG) sensors were placed bilaterally on the rectus abdominus, multifidus, biceps femoris, and rectus femoris. Across all tasks, no significant effects of load on muscle activity were found for any of the muscles. Participants rated the VEST condition as more comfortable (p < 0.05) and less restrictive (p < 0.05) than either LEODB. The findings suggest an LEODB does not alter muscle activity during bodyweight hip hinging or lifting objects from the ground. Future research should examine whether changes in muscle activity occur with durations of LEODB wear more similar to an actual work shift duration for LEOs (≥8 h).

Diaphragmatic Hernia With Incarcerated Spleen as a Complication After Lateral Anterior Column Realignment.

BACKGROUND: The creation of sagittal balance of the spine is critical in the treatment adult spinal deformity. Anterior column release (ACR) has gained traction as a minimally invasive alternative to pedicle subtraction osteotomy. By releasing the anterior longitudinal ligament, the anterior column can be lengthened and physiologic lordosis restored. Risks such as transient psoas weakness and thigh numbness have been well documented in the literature; however, diaphragmatic hernia has never been reported. OBJECTIVE: To highlight the difficulties encountered in diagnosing, managing, and treating iatrogenic diaphragmatic hernia in the setting of ACR and stress the relevant retropleural, retroperitoneal, and diaphragmatic structures during the surgical approach. METHODS: In this technical note, we discuss the relevant anatomy in a direct lateral approach to the thoracolumbar junction and the management of an iatrogenic diaphragmatic hernia, which occurred in a patient who underwent a L1 ACR. RESULTS: Three months after surgery, our patient was assessed in clinic and endorsed significant improvements in her pain and mobility. Her 3-month postoperative scoliosis x-rays demonstrated a significant improvement in her sagittal alignment, and she experienced no further negative sequelae from the iatrogenic hernia. CONCLUSION: Iatrogenic diaphragmatic hernia with an intrathoracic spleen after direct lateral ACR is a risk spine surgeons should be aware of and address promptly.

Upper body push to pull ratios in law enforcement officer recruits.

BACKGROUND: Law enforcement recruits (LER) often encounter shoulder injuries, which may cause attrition from academies. Investigating required upper body muscular fitness may inform of muscular balance around shoulder joints through anterior and posterior ratios in LER. OBJECTIVE: To investigate push to pull ratios (P2P) and factors related with P2P in LER. METHODS: LER (95 males; 12 females) completed testing during a single session in the academy's first week: body mass, one-repetition maximum (1RM) bench press, push-up repetitions (reps) to failure, and pull-up reps to failure. Calculations were: estimated pull-up 1RM=body mass+0.033*(body mass x pull-ups); endurance P2P (eP2P)=push-ups / pull-ups; strength P2P (sP2P)=bench press 1RM / estimated pull-up 1RM. Pearson correlation coefficients assessed relationships among tests and P2P (p < 0.05). RESULTS: The sP2P was positively correlated with bench press 1RM and push-ups. The eP2P was negatively associated with pull-up reps and 1RM. Females had similar eP2P, but lower sP2P than male recruits (p < 0.05). CONCLUSION: Practitioners may benefit from examining eP2P and sP2P as they should not be used interchangeably. Future research should examine whether the P2P ratios are associated with injury and subsequent inability to successfully complete law enforcement training academies.

Factors Influencing Motivation to Perform Mental and Physical Tasks During the Initial Lockdown Period of the COVID-19.

Drastic changes to lifestyles have occurred during the COVID-19 pandemic. An unintended consequence of stay at home orders is increased isolation and less social interaction for many people. For overall wellbeing it is important to stay both physically and mentally active; however, for many individual's motivation may be a barrier. There are non-modifiable (e.g. sex, age, personality, infection rates in the area) and modifiable factors (e.g. physical activity, diet, sleep) that may be associated with motivation to perform physical and mental tasks. We collected data from 794 subjects using an online survey between April 13th to May 3rd of 2020. Survey questionnaires included demographics, personality traits, diet, sleep, physical activity levels, mental workload and motivation to perform mental and physical tasks. Multiple linear regression analyses were used to assess the association between non-modifiable and modifiable variables on motivation to perform mental and physical tasks. The results of our analyses suggest that those who reported a higher quality of diet (REAP-S score), exercised vigorously, and reduced their sedentary time, reported higher motivation to perform both mental and physical tasks. Those who were employed and had higher grit were more motivated to perform physical tasks. Lower trait physical energy was associated with greater motivation to perform mental tasks. Our findings support that during challenging times, such as the COVID-19 pandemic, it is important for healthcare practitioners to emphasize the importance healthy lifestyle behaviors to prevent individuals from experiencing a lack of motivation to perform both mental and physical tasks. Future research should focus on trying to determine the directionality of the relationship between specific healthy lifestyle behaviors and motivation.

Optical Flow Estimation Improves Automated Seizure Detection in Neonatal EEG.

PURPOSE: Existing automated seizure detection algorithms report sensitivities between 43% and 77% and specificities between 56% and 90%. The algorithms suffer from false alarms when applied to neonatal EEG because of the high degree of nurse handling and rhythmic patting used to soothe neonates. Computer vision technology that quantifies movement in real time could distinguish artifactual motion and improve automated neonatal seizure detection algorithms. METHODS: The authors used video EEG recordings from 43 neonates undergoing monitoring for seizures as part of the NEOLEV2 clinical trial. The Persyst neonatal automated seizure detection algorithm ran in real time during study EEG acquisitions. Computer vision algorithms were applied to extract detailed accounts of artifactual movement of the neonate or people near the neonate though dense optical flow estimation. RESULTS: Using the methods mentioned above, 197 periods of patting activity were identified and quantified, of which 45 generated false-positive automated seizure detection events. A binary patting detection algorithm was trained with a subset of 470 event videos. This supervised detection algorithm was applied to a testing subset of 187 event videos with 8 false-positive events, which resulted in a 24% reduction in false-positive automated seizure detections and a 50% reduction in false-positive events caused by neonatal care patting, while maintaining 11 of 12 true-positive seizure detection events. CONCLUSIONS: This work presents a novel approach to improving automated seizure detection algorithms used during neonatal video EEG monitoring. This artifact detection mechanism can improve the ability of a seizure detector algorithm to distinguish between artifact and true seizure activity.

Predictive Accuracy of the Nelson Equation via BodPod Compared to Commonly Used Equations to Estimate Resting Metabolic Rate in Adults.

Indirect calorimetry (IC) is considered the gold standard for assessing resting metabolic rate (RMR). However, many people do not have access to IC devices and use prediction equations for RMR estimation. Equations using fat free mass (FFM) as a predictor have been developed to estimate RMR, as a strong relationship exists between FFM and RMR. One such equation is the Nelson equation which is used by the BodPod (BP). Yet, there is limited evidence whether the Nelson equation is superior to other common equations to predict RMR. To examine the agreement between predicted RMR from common RMR equations and the BP, and RMR measured via IC. Data from 48 healthy volunteers who completed both the BP and IC were collected. Agreement between RMR measured by BP, common regression equations, and indirect caloriometry was evaluated using repeated measures ANOVA, Bland-Altman analysis and root mean square error (RMSE). Predicted RMR values from common equations and BP were significantly different from IC with the exception of the World Health Organization (WHO) equation. Large limits of agreement and RMSE values demonstrate a large amount of error at the individual level. Despite the use of FFM, the Nelson equation does not appear to be superior to other common RMR equations. Although the WHO equation presented the best option within our sample, all equations performed poorly at the individual level. Clinicians should be aware that prediction equations may significantly under- or overestimate RMR compared to IC and when an accurate value of RMR is required, IC is recommended.

Electrochemical safety limits for clinical stimulation investigated using depth and strip electrodes in the pig brain.

Objective. Diagnostic and therapeutic electrical stimulation are increasingly utilized with the rise of neuromodulation devices. However, systematic investigations that depict the practical clinical stimulation paradigms (bipolar, two-electrode configuration) to determine the safety limits are currently lacking. Further, safe charge densities that were classically determined from conical sharp electrodes are generalized for cylindrical (depth) and flat (surface grid) electrodes completely ignoring geometric factors that govern current spreading and trajectories in tissue.Approach. This work reports the first investigations comparing stimulation limits for clinically used electrodes in two mediums: in benchtop experiments in saline andin vivoin a single acute experiment in the pig brain. We experimentally determine the geometric factors, the water electrolysis windows, and the current safety limits from voltage transients, for the sEEG, depth and surface strip electrodes in both mediums. Using four-electrode and three-electrode configuration measurements and comprehensive circuit models that accurately depict our measurements, we delineate the various elements of the stimulation medium, including the tissue-electrode interface impedance spectra, the medium impedance and the bias-dependent change in the interface impedance as a function of stimulation parameters.Main results. The results of our systematics studies suggest that safe currents in clinical bipolar stimulation determinedin vivocan be as much as 24 times smaller than those determined from benchtop experiments (for depth electrodes at a 1 ms pulse duration). Our detailed circuit modeling attributes this drastic difference in safe limits to the greatly dissimilar electrode/tissue and electrode/saline impedances.Significance. We established the electrochemical safety limits for commonly used clinical electrodesin vivoand revealed by detailied electrochemical modeling how they differ from benchtop evaluation. We argue that electrochemical limits and currents are unique for each electrode, should be measuredin vivoaccording to the protocols established in this work, and should be accounted for while setting the stimulation parameters for clinical applications including for chronic applications.

Review of operative considerations in spinal cord stem cell therapy.

Spinal cord injury (SCI) can permanently impair motor and sensory function and has a devastating cost to patients and the United States healthcare system. Stem cell transplantation for treatment of SCI is a new technique aimed at creating biological functional recovery. Operative techniques in stem cell transplantation for SCI are varied. We review various clinical treatment paradigms, surgical techniques and technical considerations important in SCI treatment. The NCBI PubMed database was queried for "SCI" and "stem cell" with a filter placed for "clinical trials". Thirty-nine articles resulted from the search and 29 were included and evaluated by study authors. A total of 10 articles were excluded (9 not SCI focused or transplantation focused, 1 canine model). Key considerations for stem cell transplantation include method of delivery (intravenous, intrathecal, intramedullary, or excision and engraftment), time course of treatment, number of treatments and time from injury until treatment. There are no phase III clinical trials yet, but decreased time from injury to treatment and a greater number of stem cell injections both seem to increase the chance of functional recovery.

Relationship Between Employment Status, Reported Physical Activity, and Sitting Time During COVID-19 Pandemic.

BACKGROUND: The COVID-19 pandemic has changed our working environment and divided workers into essential or nonessential statuses. Employment status is a major factor determining the amount of physical activity performed. Our purpose was to understand how employment status affects physical activity and sitting time. METHODS: Between April 13 and May 4, 2020, 735 full-time employed individuals responded to a survey investigating daily life and overall health during the COVID-19 pandemic. Participants reported how much physical activity they had performed in the last 7 days. Multiple linear regressions were performed for physical activity and sitting time. RESULTS: Physical activity was not associated with employment status. An interaction effect between hours worked and employment status was found for sitting time. CONCLUSIONS: Employment status was not related to physical activity; however, it did affect the amount of time spent sitting, with nonessential employees sitting more and working more hours than essential employees. Because greater amounts of daily total sitting time have been associated with increased risk of all-cause mortality, it is important that increased sitting time be attenuated by greater physical activity.

Surgical Relevance of Pediatric Anterior Clinoid Process Maturation for Anterior Skull Base Approaches.

BACKGROUND: Removal of the anterior clinoid process (ACP) can expand anterior skull base surgical corridors. ACP development and anatomical variations are poorly defined in children. OBJECTIVE: To perform a morphometric analysis of the ACP during pediatric maturation. METHODS: Measurements of ACP base thickness (ACP-BT), midpoint thickness (ACP-MT), length (ACP-L), length from optic strut to ACP tip (ACP-OS), pneumatization (ACP-pneumo), and the presence of an ossified carotico-clinoid ligament (OCCL) or interclinoid ligament (OIL) were made from high-resolution computed-tomography scans from 60 patients (ages 0-3, 4-7, 8-11 12-15, 16-18, and >18 yr). Data were analyzed by laterality, sex, and age groups using t-tests and linear regression. RESULTS: There were no significant differences in ACP parameters by laterality or sex, and no significant growth in ACP-BT or ACP-MT during development. From ages 0-3 yr to adult, mean ACP-L increased 49%, from 7.7 to 11.5 mm. The majority of ACP-L growth occurred in 2 phases between ages 0-3 to 8-11 and ages 16-18 to adult. Conversely, ACP-OS was stable from ages 0-3 to 8-11 but increased by 63% between ages 8-11 to adult. Variations in ACP morphology (OCCL/OIL/ACP-pneumo) were found in 15% (9/60) of scans. OCCL and OIL occurred in patients as young as 3 yrs, whereas ACP-pneumo was not seen in patients younger than 11 yrs. CONCLUSION: The ACP demonstrates stable thickness and a complex triphasic elongation and remodeling pattern with development, the understanding of which may facilitate removal in patients <12. Clinically relevant ACP anatomic variations can occur at any age.

Accuracy of Commonly Used Age-Predicted Maximal Heart Rate Equations.

Age-predicted maximal heart rate (APMHR) is an essential measure for healthcare professionals in determining cardiovascular response to exercise testing, exertion, and prescription. Although multiple APMHR prediction equations have been validated for specific populations, the accuracy of each within a general population requires testing. We aimed to determine which APMHR equation (Fox, Gellish, Gulati, Tanaka, Arena, Astrand, Nes, Fairbarn) most accurately predicts max heart rate (HRmax) in a general population. HRmax from 99 graded treadmill exercise tests (GXT) were measured. GXTs ended upon volitional fatigue and were only included for analysis if RER > 1.10. Individual paired t-test were performed to determine if significant differences existed between measured and predicted HRmax, along with root mean square errors for each equation. Bland-Altman plots were constructed to determine agreement between equations and measured HRmax. Significant differences between measured and predicted HRmax were found for the Gulati, Astrand, Nes, and Fairbarn (male) equations (p < 0.05). Bland-Altman plots revealed wide limits of agreement for all nine APMHR equations, suggesting poor agreement between measured and predicted HRmax. Proportional bias indicates that prediction equations under and overestimated HRmax in individuals with lower and higher measured HRmax, respectively, with the exception of the Fox equation. All equations used in this study show poor agreement between measured HRmax and APMHR. The Fox equation may represent the best option for a general population as it is less likely to under or overestimate based on individual HRmax. Individuals should use data from GXTs to determine HRmax when applicable to ensure accuracy.