Can a Blade-Stopping Mechanism on Circular Table Saws Reduce the Severity of Hand Injuries in Contact Scenarios? A Cadaveric Study.

PURPOSE: Table saws are commonly used woodworking tools that carry a substantial risk of injury. Blade-stopping technology has been developed and has the potential to reduce the frequency and severity of injury. This study aimed to evaluate this technology on human tissue and characterize the resulting injuries. METHODS: Twenty-seven fresh, frozen cadaveric specimen hands were used. Three scenarios were tested, with the specimen (1) moving forward ("forward"); (2) moving backward, such as in a kickback scenario ("reverse"); and (3) dropped from above the saw blade ("top"). Each scenario was tested at both slow (0.001 m/sec) and fast (forward: 0.6 m/sec; reverse: 0.5 m/sec; top: 2.4 m/sec) approach speeds. The severity of the injuries was characterized by anatomic evaluation and confirmed with radiographic evaluation. Injuries were classified as no laceration, superficial soft tissue injury, deep soft tissue injury, and bony injury. RESULTS: For the slow approach speed, the brake cartridge engaged in 100% of the trials for all 3 scenarios, and 100% of the specimens sustained no injuries. Forward testing at a fast approach speed revealed the brake cartridge engaged in 89% of the trials (injuries: 4 superficial, 2 deep, 3 bony). Reverse testing at a fast approach speed revealed the brake cartridge engaged in 11% of trials (injuries: 1 superficial, 8 bony). Top testing at a fast approach speed revealed the brake cartridge engaged in 89% of the trials (injuries: 9 bony). CONCLUSIONS: Modern blade-stopping technology did not prevent all traumatic hand injuries in fast approach speed scenarios, but it reduced the incidence and severity of injuries. The technology was more effective at low approach speed scenarios. CLINICAL RELEVANCE: The findings of this study provide information to help understand the factors that can prevent or reduce the severity of contact injuries (hand, finger, or thumb) for operators of table saws.

Medial Nucleus Accumbens Projections to the Ventral Tegmental Area Control Food Consumption.

Decades of research have shown that the NAc is a critical region influencing addiction, mood, and food consumption through its effects on reinforcement learning, motivation, and hedonic experience. Pharmacological studies have demonstrated that inhibition of the NAc shell induces voracious feeding, leading to the hypothesis that the inhibitory projections that emerge from the NAc normally act to restrict feeding. While much of this work has focused on projections to the lateral hypothalamus, the role of NAc projections to the VTA in the control food intake has been largely unexplored. Using a retrograde viral labeling technique and real-time monitoring of neural activity with fiber photometry, we find that medial NAc shell projections to the VTA (mNAc→VTA) are inhibited during food-seeking and food consumption in male mice. We also demonstrate that this circuit bidirectionally controls feeding: optogenetic activation of NAc projections to the VTA inhibits food-seeking and food intake (in both sexes), while optogenetic inhibition of this circuit potentiates food-seeking behavior. Additionally, we show that activity of the NAc to VTA pathway is necessary for adaptive inhibition of food intake in response to external cues. These data provide new insight into NAc control over feeding in mice, and contribute to an emerging literature elucidating the role of inhibitory midbrain feedback within the mesolimbic circuit.SIGNIFICANCE STATEMENT The medial NAc has long been known to control consummatory behavior, with particular focus on accumbens projections to the lateral hypothalamus. Conversely, NAc projections to the VTA have mainly been studied in the context of drug reward. We show that NAc projections to the VTA bidirectionally control food intake, consistent with a permissive role in feeding. Additionally, we show that this circuit is normally inactivated during consumption and food-seeking. Together, these findings elucidate how mesolimbic circuits control food consumption.

Evaluation of the Functional Movement Screen and a Novel Basketball Mobility Test as an Injury Prediction Tool for Collegiate Basketball Players.

Bond, CW, Dorman, JC, Odney, TO, Roggenbuck, SJ, Young, SW, and Munce, TA. Evaluation of the functional movement screen and a novel basketball mobility test as an injury prediction tool for collegiate basketball players. J Strength Cond Res 33(6): 1590-1601, 2019-Identifying injury risk and implementing preventive measures can assist in reducing injury occurrence and may ultimately improve athletic performance. Improper movement patterns often contribute to musculoskeletal (MSK) injuries. The validity of the Functional Movement Screen (FMS) as an injury prediction tool for athletes remains unclear. We designed the Basketball-Specific Mobility Test (BMT) to represent the neuromuscular demands of basketball and identify deficiencies that may be indicative of greater MSK injury risk while playing this sport. The aim of this study was to examine the association of FMS and BMT scores with injury occurrence in collegiate basketball players. We hypothesized that the BMT would be a better predictor of injury risk than the FMS, and that scores from both tests would have a higher association with severe MSK injuries than minor, non-MSK injuries. One-hundred nineteen male and female collegiate basketball players from 4 Upper Midwest universities were assessed preseason (PRE) and postseason (POST) using the FMS and BMT. In-season injury records were collected from the schools' athletic trainers and were classified by type and severity. During the season, 56 of 119 players were injured, resulting in 96 total injuries. Injured athletes' PRE FMS scores demonstrated negligible effects compared with uninjured athletes' PRE scores (d < 0.20), whereas some BMT scores showed potentially meaningful effects (d > 0.20). Although specificity of the FMS and BMT to predict injury was relatively high (FMS 85.7-87.6; BMT 42.0-88.0), sensitivity (FMS 14.2-22.7; BMT 11.6-39.1), odds ratios (FMS 1.00-2.08; BMT 0.47-1.06), and injury prediction capacities (area under the curve; FMS 0.43-0.49; BMT 0.49-0.59) of the tests were low. Although the FMS and BMT may be suitable for identifying MSK deficiencies, they do not accurately determine injury risk in collegiate basketball players. Injury risk assessments may be improved by targeting specific injury mechanisms and the conditions in which they occur.

Regulation of Alcohol Extinction and Cue-Induced Reinstatement by Specific Projections among Medial Prefrontal Cortex, Nucleus Accumbens, and Basolateral Amygdala.

The ability to inhibit drinking is a significant challenge for recovering alcoholics, especially in the presence of alcohol-associated cues. Previous studies have demonstrated that the regulation of cue-guided alcohol seeking is mediated by the basolateral amygdala (BLA), nucleus accumbens (NAc), and medial prefrontal cortex (mPFC). However, given the high interconnectivity between these structures, it is unclear how mPFC projections to each subcortical structure, as well as projections between BLA and NAc, mediate alcohol-seeking behaviors. Here, we evaluate how cortico-striatal, cortico-amygdalar, and amygdalo-striatal projections control extinction and relapse in a rat model of alcohol seeking. Specifically, we used a combinatorial viral technique to express diphtheria toxin receptors in specific neuron populations based on their projection targets. We then used this strategy to create directionally selective ablations of three distinct pathways after acquisition of ethanol self-administration but before extinction and reinstatement. We demonstrate that ablation of mPFC neurons projecting to NAc, but not BLA, blocks cue-induced reinstatement of alcohol seeking and neither pathway is necessary for extinction of responding. Further, we show that ablating BLA neurons that project to NAc disrupts extinction of alcohol approach behaviors and attenuates reinstatement. Together, these data provide evidence that the mPFC→NAc pathway is necessary for cue-induced reinstatement of alcohol seeking, expand our understanding of how the BLA→NAc pathway regulates alcohol behavior, and introduce a new methodology for the manipulation of target-specific neural projections.SIGNIFICANCE STATEMENT The vast majority of recovering alcoholics will relapse at least once and understanding how the brain regulates relapse will be key to developing more effective behavior and pharmacological therapies for alcoholism. Given the high interconnectivity of cortical, striatal, and limbic structures that regulate alcohol intake, it has been difficult to disentangle how separate projections between them may control different aspects of these complex behaviors. Here, we demonstrate a new approach for noninvasively ablating each of these pathways and testing their necessity for both extinction and relapse. We show that inputs to the nucleus accumbens from medial prefrontal cortex and amygdala regulate alcohol-seeking behaviors differentially, adding to our understanding of the neural control of alcoholism.

Evaluation of Skating Top Speed, Acceleration, and Multiple Repeated Sprint Speed Ice Hockey Performance Tests.

Bond, CW, Bennett, TW, and Noonan, BC. Evaluation of skating top speed, acceleration, and multiple repeated sprint speed ice hockey performance tests. J Strength Cond Res 32(8): 2273-2283, 2018-Skating speed, acceleration (ACC), and economy are important attributes related to ice hockey success and should ideally be tested on the ice in a reliable and time efficient manner that is accessible to coaches at all levels of the sport. The purpose of this study was to determine the reliability of certain on-ice tests and further, to use these results to evaluate changes in performance across a season. It was hypothesized that the tests' reliability would be excellent and that players would demonstrate improvements in performance associated with enhanced physiological conditioning. Forty male ice hockey players (16.2 ± 0.8 years, 1.76 ± 0.06 m, 73.7 ± 9.8 kg) completed top speed (TS), ACC, and multiple repeated sprint time (MRST) tests twice in the preseason (PRE 1 and 2) 1 week apart to examine reliability and once postseason (POST) to examine changes across the season. A high-speed video camera was used to time each test. The TS, ACC, and MRST demonstrated excellent within- and between-day reliability (interclass correlation coefficient [ICC] ≥ 0.83, typical error [TE] ≤ 2.6%) as well as within- and between-rater reliability (ICC ≥ 0.86, TE ≤ 0.5%). The team's TS and ACC were similar at all 3 assessments (p > 0.05), whereas MRST was faster at POST than at PRE 1 (p < 0.05). This test battery is reliable, time efficient, and inexpensive. All 3 tests may be used in team selection and identification of fatigue or overtraining. The MRST may be the most sensitive to short-term improvements related to ice hockey conditioning.

Asymmetry of lower extremity force and muscle activation during knee extension and functional tasks.

INTRODUCTION: Strength and power asymmetries of >10% may negatively impact physical function. METHODS: Twenty-four healthy participants, 30-60 years of age, were assessed for muscle power asymmetry during isokinetic knee extension and ground reaction force asymmetry during chair-rise and vertical jump tasks. Neuromuscular activation asymmetry and coactivation of vastus lateralis (VL) and biceps femoris (BF) were assessed in each condition. Symmetric (SG) and asymmetric (AG) groups were identified using a 10% knee extension power asymmetry criterion. RESULTS: The AG had greater chair-rise rate of force development asymmetry (P = 0.003, d = 1.29), but a similar chair-rise and vertical jump peak force asymmetry as the SG. Large group effects were found for VL activation asymmetry during knee extension (P = 0.047, d = 0.87), BF activation asymmetry during vertical jump (P = 0.015, d = 1.12), and strong leg coactivation during vertical jump (P = 0.028, d = 0.96). CONCLUSIONS: Compensation for muscle power asymmetry may occur during functional tasks, potentially through differential activation of strong and weak leg muscles. Muscle Nerve 56: 495-504, 2017.

Comparison of Three Timing Systems: Reliability and Best Practice Recommendations in Timing Short-Duration Sprints.

Bond, CW, Willaert, EM, and Noonan, BC. Comparison of three timing systems: reliability and best practice recommendations in timing short-duration sprints. J Strength Cond Res 31(4): 1062-1071, 2017-With the importance placed on athletic speed, it is important to use a valid and reliable timing system, particularly in sprints of short duration. Unfortunately, many of the commonly used timing systems have not been rigorously evaluated. This study aimed to compare results from a single-beam infrared photocell (PC), single-beam laser with a microprocessor (LA), and a previously validated video camera (VC) sacrum-based timing system; and in doing so, determine these systems' reliabilities, and establish best practices for increasing reliability. It was hypothesized that PC and LA times would be different from VC times and show reduced reliability compared with VC. Fifteen athletes performed 5 repetitions of a 60-foot maximal effort sprint with split times recorded for the first and second half. Photocell and LA full-time and first-half split times were significantly slower than VC (p < 0.001), but almost identical for the second half split (p = 0.08). Repeated sprint analysis showed that VC tended to have smaller SD compared with PC and LA for first-half split (0.05 vs. 0.08 vs. 0.09 seconds, respectively) and total time (0.09 vs. 0.10 vs. 0.11 seconds, respectively). Time differences were more dependent on initial forward lean and varying body segments triggering the beam, than on a systematic instrument error. The increased variability of PC and LA systems dampen the ability to determine whether meaningful change has occurred. The VC system allows for very valid and reliable measurements of an athlete's sprint time, especially in distances <30 feet.

Reliability of Three Timing Systems Used to Time Short on Ice-Skating Sprints in Ice Hockey Players.

Bond, CW, Willaert, EM, Rudningen, KE, and Noonan, BC. Reliability of three timing systems used to time short on ice-skating sprints in ice hockey players. J Strength Cond Res 31(12): 3279-3286, 2017-Speed and acceleration are highly valued in ice hockey and frequently assessed using timing systems. Coaches must use reliable timing systems to assess these attributes, but many systems have not been thoroughly evaluated and the required number of sprint repetitions to obtain the coach's desired degree of reliability for a system may be impractical. This study aimed to compare the reliability of a single photocell (PC), a single laser with a microprocessor (LA), and a digital video camera (VC); and in doing so, evaluate the influence of completing additional sprint repetitions on each systems' reliability. We hypothesized that PC and LA would yield different times, have inferior reliability, and require a larger number of sprint repetitions to obtain the same degree of reliability compared with VC. Seventeen male ice hockey players completed 5 repetitions of a 9.15 m on ice-skating sprint timed simultaneously by PC, LA, and VC. The times obtained from VC were narrowly distributed around the mean compared with PC and LA and resulted in a mean sprint time approximately 0.05 and 0.07 second faster than PC and LA, respectively {PC: 1.74 second (95% confidence interval [1.72-1.76]); LA: 1.76 second [1.74-1.78]; VC: 1.69 second [1.67-1.70]}. When 2 sprint repetitions were completed, PC and LA typical error (TE) and smallest worthwhile difference (SWD) were 2.8- and 4.3-fold greater than VC, respectively. As more repetitions were completed, TE and SWD for PC and LA improved but remained approximately 2-fold greater than VC even when 5 repetitions were completed. With a smaller TE and SWD, VC was able to detect smaller "real" changes in a player's sprint performance over time compared with PC and LA.

THE EFFECT OF TIME AND SEX ON POST-ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION PSYCHOLOGICAL PATIENT REPORTED OUTCOME MEASURE SCORES.

CONTEXT: Low scores on psychological patient reported outcomes measures (PROMs), including the anterior cruciate ligament-return to sport after injury (ACL-RSI) and injury-psychological readiness to return to sport (I-PRRS), after anterior cruciate ligament (ACL) reconstruction (ACLR) have been associated with a maladaptive psychological response to injury and poor prognosis. OBJECTIVE: The purpose of this study was to assess the effect of time post-ACLR and sex on ACL-RSI and I-PRRS scores and generate normative reference curves. It was hypothesized that males would demonstrate higher ACL-RSI and I-PRRS scores than females in the first 1-year post-ACLR. DESIGN: Case series. SETTING: Outpatient sports medicine and orthopedic clinic. PATIENTS: 507 patients post-primary ACLR 12-to-30-years-old with 796 ACL-RSI or I-PRRS scores one or more times between 0- and 1-year post-ACLR (age at ACLR: 17.9 ± 3.0 y). MAIN OUTCOME MEASURES: An honest broker provided anonymous data from our institution's knee injury clinical database. Generalized additive models for location, scale, and shape and generalized least squares analyses were used to assess the effect of time post-ACLR and sex on ACL-RSI and I-PRRS scores. RESULTS: ACL-RSI and I-PRRS scores increased over time post-ACLR, and males had higher scores compared to females up until approximately five months post-ACLR with scores converging thereafter. CONCLUSIONS: Males report higher ACL-RSI and I-PRRS scores compared to females in the initial stages of rehabilitation, but scores converge between sexes at times associated with return to play following ACLR. Normative reference curves can be used to objectively appraise patients' ACL-RSI and I-PRRS scores at any time point post-ACLR. This may lead to timely identification of patients with scores or changes in scores over time post-ACLR associated with a maladaptive psychological response to injury and a poor prognosis and optimized ACLR outcomes.

Retrospective Longitudinal Evaluation of Male Firefighter's Body Composition and Cardiovascular Health.

OBJECTIVE: Describe firefighter body composition and cardiovascular health as a function of age. METHODS: 217 male firefighters with 1922 distinct evaluations over 23-years were included in this retrospective analysis. The firefighters had their height, mass, six-site skin-fold, blood pressure, and resting heart rate measured annually. Linear mixed models were used to analyze the effect of age. Significance was set to P < 0.05. RESULTS: With each 1-year increase in age, mass (0.42 kg, P < 0.001), body mass index (0.13 kg m-2, P < 0.001), body fat percentage (0.18%, P < 0.001), fat mass (0.25 kg, P < 0.001), and fat free mass (0.15 kg, P < 0.001) increased. Systolic blood pressure (-0.09 mm Hg, P = 0.263), diastolic blood pressure (0.05 mm Hg, P = 0.308), and resting heart rate (0.07 beats min-1, P = 0.291) did not change. CONCLUSIONS: Interventions to maintain healthy body composition are critical to reduce sudden cardiovascular related death risk.

Limb occlusion pressure for blood flow restricted exercise: Variability and relations with participant characteristics.

OBJECTIVE: Assess lower-extremity blood flow restricted exercise (BFR) limb occlusion pressure (LOP) variability and identify related intrinsic characteristics using a portable Delphi BFR system. DESIGN: Repeated measures. SETTING: Laboratory. PARTICIPANTS: Forty-two healthy males (n = 25) and females (n = 17) (25.8 ± 5.2 y, 1.76 ±0 .09 m, 78.9 ± 14.9 kg) completed two visits. Brachial artery blood pressure, thigh circumferences (TC), and LOP were measured supine. MAIN OUTCOME MEASURES: Linear mixed-effects models (LMM) and generalizability theory were used to evaluate LOP between legs and days, determine intrinsic characteristic relations, and assess random variance components. RESULTS: LOP was not different between legs (p = .730) or days (p = .916; grand mean = 183.7 mmHg [178.4, 189.1]). LOP varied significantly between participants (p = .011, standard error = 47.3 mmHg). 47% of LOP variance was between participants, 18% and 6% was within participants between days and legs, respectively, and 28% was associated with random error. The relative error variance was 14.4 mmHg. Pulse pressure (PP) (p = .005) and TC (p = .040) were positively associated with LOP. A LMM including PP and TC predicted LOP with a mean absolute difference of 11.1 mmHg [9.7, 12.6] compared to measured LOP. CONCLUSIONS: The relative error variance suggests that clinicians should measure LOP consistently for each patient to ensure BFR safety and effectiveness.

Effect of Jump Direction and External Load on Single-Legged Jump-Landing Biomechanics.

External load may increase an individual's risk of non-contact anterior cruciate ligament (ACL) injury during single-legged jump-landing (SLJL). This study evaluated the effects of jump direction and external load on hip and knee joint motion and time to stabilization (TTS) during SLJL. Seventeen active males (n = 8) and females (22.2 ± 3.0 y, 1.75 ± 0.08 m, 73.4 ± 12.0 kg) participated in this randomized, crossover designed study. Single-legged jump-landings performed in two conditions, including without external load (BW) and with a torso-worn weight vest equal to 10% of the participant's body weight (BW+10%), from backward, forward, medial, and lateral SLJL directions. Two-way repeated measures ANOVA did not identify any significant interactions (P > .01, η2: < .001 - .037), but some main effects for condition with small effect sizes were identified (P < .01, η2: .009 - .039). Several main effects for SLJL direction were identified with larger effect sizes (P < .01, η2: .010 - .574). This suggests SLJL direction may challenge different components of SLJL biomechanics, and that recreationally active, college-aged individuals may possess effective compensatory mechanisms that can mitigate the effect of BW+10%.

Dynamic Postural Stability in Active, Adolescent Males Following Repeated Bouts of Aerobic Exercise in Hot and Temperate Environments: A Pilot Study.

INTRODUCTION: Proper jump-landing neuromuscular control is crucial in mitigating lower-extremity musculoskeletal injuries. The presence of fatigue, especially in extreme environments, may degrade dynamic postural stability (DPS) and result in lower-extremity injuries. This study aimed to evaluate the influence of moderate intensity exercise in hot (HOT) and temperate (TEMP) ambient temperatures and residual effects of a previous bout on DPS during a single-legged jump-landing. It was hypothesized that the participants would display worse DPS after HOT compared to TEMP. METHODS: Six recreationally active young males (16.8 ± 0.7 year, 1.88 ± 0.12 m, 83.8 ± 19.8 kg) completed two, 60-minute bouts of exercise with 60 minutes of rest between bouts in both HOT (35°C) and TEMP (22.2°C). Heart rate and core body temperature (Tc) were monitored continuously, and DPS was assessed before and after each bout. RESULTS: The DPS time and condition effects were not identified (p > 0.05), but HOT elicited some notable (d > 0.20) increases in heart rate, Tc, and DPS compared to TEMP. CONCLUSIONS: The DPS decrements varied between subjects suggesting individual-specific etiology. Repeated bouts of exercise in HOT may place an individual at a greater risk for injury than TEMP if proper prevention strategies are not used.

The Effect of Static Stretching, Mini-Band Warm-Ups, Medicine-Ball Warm-Ups, and a Light Jogging Warm-Up on Common Athletic Ability Tests.

Proper warm-up is important for facilitating peak athletic performance and reducing injury risk; yet, warm-up procedures vary considerably amongst coaches and athletes. The purpose of this study was to assess the effect of a static stretching, medicine-ball, and mini-band warm-ups relative to a light jogging warm-up only on athletic ability test performance. It was hypothesized that static stretching would negatively affect performance, while medicine-ball and mini-band warm-ups would positively affect performance relative to light jogging only. Twelve female collegiate soccer players (19.3 ± 1.2y, 65.2 ± 7.5kg, 1.67 ± 0.07m) participated in this study. Athletes completed each warm-up protocol and all of the athletic performance tests over four sessions in a semi-randomized, counterbalanced order. An omnibus MANOVA with vertical jump height, medicine ball throw distance, 10m and 20m sprint time, and T-test time as the dependent variables was not significant indicating that warm up did not have an effect on subsequent athletic ability test performance [Wilks' λ = 0.64, F(15,110) = 1.28, p = 0.23, η2 = 0.14]. Static stretching warm-up did not negatively influence athletic potential compared to mini-band and medicine ball warm-ups, though the most optimal warm-up is likely athlete specific.

Handgrip Strength Asymmetry and Weakness May Accelerate Time to Mortality in Aging Americans.

OBJECTIVES: Assessing handgrip strength (HGS) asymmetry may provide insights into HGS as a prognostic assessment of strength capacity and vitality. This study sought to determine the associations of HGS asymmetry and weakness on time to mortality in aging Americans. DESIGN: Longitudinal panel. SETTING: Secondary analyses of data from participants aged ≥50 years from the 2006‒2014 waves of the Health and Retirement Study. PARTICIPANTS: The analytic sample included 19,325 Americans who identified hand dominance and had measures of HGS for both hands in a single wave. MEASURES: A handgrip dynamometer was used to measure HGS. Men and women who were considered weak had HGS <26 kg and <16 kg, respectively. The highest HGS values from the dominant and nondominant hands were used to calculate HGS ratio: (nondominant HGS/dominant HGS). Those with HGS ratio <0.90 or >1.10 had any HGS asymmetry. Moreover, participants with HGS ratio <0.90 had dominant HGS asymmetry, whereas those with HGS ratio >1.10 had nondominant HGS asymmetry. The National Death Index and postmortem interviews verified date of death. Covariate-adjusted Cox models were used for analyses. RESULTS: Those with any HGS asymmetry had a 1.10 [95% confidence interval (CI) 1.03‒1.17] higher hazard for mortality, while those with weakness had a 1.44 (CI 1.32‒1.58) higher hazard for mortality. Likewise, participants with dominant HGS asymmetry had a 1.11 (CI 1.03‒1.18) higher hazard for mortality, and those with weakness had a 1.45 (CI 1.32‒1.58) higher hazard for mortality; however, the association was not significant for those with nondominant HGS asymmetry (hazard ratio: 1.07; CI 0.96‒1.18). CONCLUSIONS AND IMPLICATIONS: HGS asymmetry and weakness are markers of impaired strength capacity that independently accelerate time to mortality, but the magnitude of these associations was more prominent for weakness. Nevertheless, assessments of asymmetric HGS are a simple adjunct analysis that may show promise for increasing the prognostic value of handgrip dynamometers.

Blood Flow Restriction Resistance Exercise as a Rehabilitation Modality Following Orthopaedic Surgery: A Review of Venous Thromboembolism Risk.

Synopsis Restoration of skeletal muscle mass and strength is critical to successful outcomes following orthopaedic surgery. Blood flow restriction (BFR) resistance exercise has emerged as a promising means of augmenting traditional low-intensity physical rehabilitation exercise and has yielded successful outcomes in a wide range of applications. Though BFR is well tolerated and safe for most individuals, patients who have undergone orthopaedic surgery may be an exception, due to their heightened risk for venous thromboembolism (VTE). While the pathogenesis of VTE is multifactorial and specific to the individual, it is commonly described as a combination of blood stasis, endothelial injury, and alterations in the constituents of the blood leading to hypercoagulability. The collective literature suggests that, given the pathogenic mechanisms of VTE, limited use of a wide, partially occluding cuff during resistance exercise should be low risk, and the likelihood that BFR would directly cause a VTE event is remote. Alternatively, it is plausible that BFR may enhance blood flow and promote fibrinolysis. Of greater concern is the individual with pre-existing asymptomatic VTE, which could be dislodged during BFR. However, it is unknown whether the direct risk associated with BFR is greater than the risk accompanying traditional exercise alone. Presently, there are no universally agreed-upon standards indicating which postsurgical orthopaedic patients may perform BFR safely. While excluding all these patients from BFR may be overly cautious, clinicians need to thoroughly screen for VTE signs and symptoms, be cognizant of each patient's risk factors, and use proper equipment and prescription methods prior to initiating BFR. J Orthop Sports Phys Ther 2019;49(1):17-27. Epub 12 Sep 2018. doi:10.2519/jospt.2019.8375.

Occupational-Specific Strength Predicts Astronaut-Related Task Performance in a Weighted Suit.

BACKGROUND: Future space missions beyond low Earth orbit will require deconditioned astronauts to perform occupationally relevant tasks within a planetary spacesuit. The prediction of time-to-completion (TTC) of astronaut tasks will be critical for crew safety, autonomous operations, and mission success. This exploratory study determined if the addition of task-specific strength testing to current standard lower body testing would enhance the prediction of TTC in a 1-G test battery. METHODS: Eight healthy participants completed NASA lower body strength tests, occupationally specific strength tests, and performed six task simulations (hand drilling, construction wrenching, incline walking, collecting weighted samples, and dragging an unresponsive crewmember to safety) in a 48-kg weighted suit. The TTC for each task was recorded and summed to obtain a total TTC for the test battery. Linear regression was used to predict total TTC with two models: 1) NASA lower body strength tests; and 2) NASA lower body strength tests + occupationally specific strength tests. RESULTS: Total TTC of the test battery ranged from 20.2-44.5 min. The lower body strength test alone accounted for 61% of the variability in total TTC. The addition of hand drilling and wrenching strength tests accounted for 99% of the variability in total TTC. DISCUSSION: Adding occupationally specific strength tests (hand drilling and wrenching) to standard lower body strength tests successfully predicted total TTC in a performance test battery within a weighted suit. Future research should couple these strength tests with higher fidelity task simulations to determine the utility and efficacy of task performance prediction.Taylor A, Kotarsky CJ, Bond CW, Hackney KJ. Occupational-specific strength predicts astronaut-related task performance in a weighted suit. Aerosp Med Hum Perform. 2018; 89(1):58-62.

Knee extensor power asymmetry is unrelated to functional mobility of older adults.

PURPOSE: To determine whether knee extensor power asymmetry limits functional mobility of older adults who possess muscle weakness. METHODS: Knee extensor power was measured in 36 older men and women (76.0±7.6yr), for each leg, on an isokinetic dynamometer at 60, 180, and 300degs-1 and power asymmetry was calculated as the percent difference in power between strong and weak legs, at each isokinetic velocity. 400-m walk, stair ascent, and five-repetition chair rise tests were performed to assess functional mobility. Pearson correlations were used to examine the relationship between weak leg power, strong leg power, power asymmetry, and 400-m walk time, stair ascent time, and chair rise time. Participants were then stratified into low power-high asymmetry (LP-HA), low power-low asymmetry (LP-LA), high power-high asymmetry (HP-HA), and high power-low asymmetry (HP-LA) groups who were compared for functional mobility. RESULTS: Knee extensor power asymmetry was unrelated to 400-m walk time (r=0.16, p=0.180), stair ascent time (r=0.22, p=0.094), or chair rise time (r=0.03, p=0.437), whereas weak and strong leg powers were equally associated with 400-m time (r=-0.62, p<0.001; r=-0.62, p<0.001), stair ascent time (r=-0.55, p<0.001; r=-0.57, p<0.001), and chair rise time (r=-0.28, p=0.048; r=-0.31, p=0.032), respectively. Power asymmetry was lowest at 60degs-1 (12%), and increased with contraction velocity (p=0.001) to 15% at 180degs-1 and to 20% at 300degs-1. LP-HA exhibited 26% slower 400-walk time than HP-LA (p=0.015) and 19% slower than HP-HA (p=0.037). LP-HA had 31% slower stair ascent time than HP-LA (p=0.033). There were no differences in chair rise performance between groups. CONCLUSIONS: Knee extensor power asymmetry was unrelated to 400-m walk, stair ascent, and chair rise performance in older adults. Weak and strong limb powers were equally related to these functional measures, but a leftward shift of the power-mobility curve exists for the weak leg that may hinder clinical assessment if strength or power is measured on a single limb and symmetry is assumed. The greatest degree of knee extensor power asymmetry occurred at the fastest isokinetic velocity, which suggests high-speed muscle contractions may better differentiate laterality of function in older individuals.

Acute and chronic administration of a low-dose combination of topiramate and ondansetron reduces ethanol's reinforcing effects in male alcohol preferring (P) rats.

Topiramate (a GABA/glutamate modulator) and ondansetron (a serotonin-3 antagonist) have shown promise as treatments for alcohol use disorders (AUDs), although efficacy is modest/variable for both medications. We recently showed in animal models of consumption and relapse that acute treatment with a combination of these medications was more efficacious than either alone. To determine whether the mechanism for its beneficial effects is through modulation of ethanol's reinforcing effects, we measured the effect of this combination in male alcohol preferring (P) rats (N = 22) responding for ethanol under a progressive-ratio (PR) schedule. Low doses, which either do not affect (ondansetron; 0.001 mg/kg) or only modestly affect (topiramate; 10 mg/kg) alcohol-related behaviors on their own, were selected in an attempt to maximize their combined efficacy while minimizing potential side effects. In addition to acute treatment (1 day), the effects of chronic administration (10 days) were examined in an attempt to model human treatment approaches. The effects of the combination were compared with the low dose of topiramate alone hypothesizing that the combination would be more efficacious than topiramate alone. Although both topiramate and the combination similarly reduced PR responding for ethanol following acute treatment and during the initial phase of chronic treatment (Days 1-5), after repeated administration (Days 6-10), only the combination produced a sustained reduction in ethanol-maintained responding. These results suggest an advantage of the combination over topiramate alone at producing a sustained reduction in ethanol's reinforcing effects following prolonged treatment, and lend further support for its use as a potential treatment for AUDs.