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Computerized agility training (CAT) products are frequently suggested to improve agility. However, these claims often are made without unbiased scientific support. Therefore, the purpose of this study was (a) to determine the reliability and effectiveness of a 4-week CAT training program on foot speed (FS) and choice reaction (REACT), and (b) to assess whether training on the CAT would facilitate the improvement of a separate change-of-direction (COD) test in non-agility-trained, but active, men and women. Twenty-three participants (15 men, 8 women) pre- and posttested on FS, REACT, and COD drills. Eleven of those participants (7 men, 4 women) engaged in 4 weeks of training on the FS and REACT drills (EX). The remaining 12 (8 men, 4 women) did not participate in the training and served as controls (CON). Coefficients of variation indicate strong precision for FS (6.9%) and REACT (2.6%). Test-retest reliability, as analyzed by intraclass correlations (ICC), were high for both FS and REACT (0.89). Significant test-by-group interactions were observed for all three tests: FS (p = 0.004), REACT (p = 0.011), and COD (p = 0.049). Post hoc analysis indicated that EX increased foot contacts for the FS drill (p = 0.006), whereas REACT and COD demonstrated decreases in time to completion (p = 0.013 and 0.038, respectively). The CON group did not improve on any of the tests. This study indicates that the chosen CAT is an accurate and reliable tool for measuring foot speed and reaction time. These data justify the use of this CAT in analyzing foot speed and reaction time. Altogether, 4 weeks of foot speed and reaction training on the chosen CAT produced improvements in overall agility in non-agility-trained, but active, men and women. These data warrant the integration of such a device into the training program of untrained athletes attempting to improve agility. [ABSTRACT FROM AUTHOR]

Oxidative stress seems to be involved in the pathogenesis of Parkinson disease (PD). Exercise training can increase endogenous antioxidant protection and decrease the production of reactive oxygen and nitrogen species. PURPOSE:: To investigate the effect of exercise training on oxidative status in persons with PD. METHODS:: Sixteen subjects with PD were match-randomly assigned to resistance exercise (n = 8) or a no-exercise control group (n = 8) on the basis of disease stage (Hoehn and Yahr stages I and II) and sex. Supervised exercise was performed twice weekly for 8 wk, consisting of three sets each of the leg press, leg curl, and calf press. Resting blood samples were taken from subjects before and after the intervention and assayed for markers of oxidative stress [malondialdehyde (MDA) and hydrogen peroxide (H2O2)] and antioxidant capacity (superoxide dismutase, catalase, glutathione peroxidase, and trolox-equivalent antioxidant capacity). RESULTS:: The exercise program was well-tolerated and associated with modest trends toward decreased oxidative stress and increased antioxidant capacity. The two biomarkers of oxidative stress were decreased after exercise training [MDA (15%) and H2O2 (16%)]. With these changes, a postintervention difference was apparent between the resistance exercise training and control groups for H2O2 (P = 0.007), with a trend for difference noted for MDA (P = 0.06). The mean increases in superoxide dismutase (9%) and glutathione peroxidase (15%) noted in the exercise training group were not statistically significant (P > 0.05). CONCLUSIONS:: Short-term resistance training may be associated with reduced oxidative stress in subjects with PD. Future studies with larger samples, inclusive of a higher volume of resistance exercise, are needed to extend these findings. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the influence of myosin heavy chain (MHC) isoform composition and training status on the mechanomyographic (MMG) amplitude versus isometric torque relationship for the vastus lateralis. Five resistance-trained (mean +/- SD age = 23.2 +/- 3.7 years), 5 aerobically trained (mean +/- SD age = 32.6 +/- 5.2 years), and 5 sedentary (mean +/- SD age = 23.4 +/- 4.1 years) men performed isometric muscle actions of the leg extensors in 20% increments from 20% to 100% of the maximum voluntary contraction. Biopsies from the vastus lateralis revealed that the MHC composition for the resistance-trained subjects was 59.0 +/- 4.2% Type IIa, 0.1 +/- 0.1% Type IIx, and 40.9 +/- 4.3% Type I. The aerobically-trained subjects had 27.4 +/- 7.8% Type IIa, 0.0 +/- 0.0% Type IIx, and 72.6 +/- 7.8% Type I MHC. The sedentary subjects had 42.1 +/- 7.8% Type IIa, 17.8 +/- 6.4% Type IIx, and 40.1 +/- 10.9% Type I MHC. There were no consistent patterns of responses for the resistance-trained, aerobically trained, or sedentary subjects for MMG amplitude versus torque. Thus, differences in MHC isoform composition and training status did not explain the unique torque-related patterns for MMG amplitude. [ABSTRACT FROM AUTHOR]

Weightlifting exercises and methods are essential for the strength and conditioning professional. This article reviews the underlying physiology and biomechanics of these exercises and training methods. [ABSTRACT FROM AUTHOR]

To determine the effects of 12 weeks of resistance exercise with MYOVIVE and/or colostrum supplementation, 19 male and female recreationally weight-trained subjects (X +/- SE; age = 28.3 +/- 6.9 yrs; hgt = 68.2 +/- 3.8 cm) were divided into MYOVIVE + colostrum (n = 4), MYOVIVE + casein & whey (n = 4), colostrum + casein & whey (n = 6), and casein & whey (n = 5) groups. All groups similarly increased (p < .05) 1 repetition maximum (RM) leg press (kg; pre = 158.6 +/- 12.8, post = 189.3 +/- 11.3), body mass (kg; pre = 79.0 +/- 3.2, post = 80.7 +/- 3.8), and lean body mass (kg; pre = 60.1 +/- 3.1, post = 62.2 +/- 2.8). Increases were observed for peak force (N; all loads), peak velocity (m x s[-1]; 70% & 40% 1 RM), and peak power (W; 70% & 40% 1 RM) for all groups for the leg press exercise, with no differences between groups. When performance data were adjusted for body mass, lean body mass, lower body lean mass as determined by DEXA, or % change, no group differences were observed. Relative (%) fiber type content, cross-sectional areas (microm[2]), % fiber type areas, or % myosin heavy chain expression did not change for any group. These data suggest that MYOVIVE and colostrum supplementation have no greater effect on cellular and performance adaptations when compared to casein and whey protein. [ABSTRACT FROM AUTHOR]

Objective: To compare immune function in female rowers and controls in the resting state, and then correlate the results with a two month history of upper respiratory tract infection (URTI).Methods: Subjects included 20 elite female rowers located at the ARCO Olympic Training Centre in Chula Vista, California, and 19 non-athletic female controls. These two groups were compared cross sectionally for immune function and infection rates.Results: Granulocyte/monocyte phagocytosis, oxidative burst activity, and plasma cytokine concentrations (interleukin-6, tumour necrosis factor-alpha, and interleukin-1 receptor antagonist) did not differ significantly between groups. Phytohaemagglutinin induced lymphocyte proliferative response (adjusted whole blood method) was significantly higher (31% and 36% for optimal and suboptimal concentrations respectively) in rowers than in controls. Natural killer cell activity was substantially higher (1.6-fold for total lytic units) in the female rowers than in controls. Two month health logs disclosed 5.2 (1.2) and 3.3 (1.1) days with URTI symptoms for the rowers and controls respectively (p = 0.268). For all 39 subjects combined, and for the 20 rowers separately, none of the immune parameters correlated significantly with number of days with URTI symptoms.Conclusions: In this cross sectional comparison of elite female rowers and non-athletes, a group difference was found for natural killer cell activity and phytohaemagglutinin induced proliferative response (whole blood technique), but not other measures of immune function. The number of days with URTI symptoms during the spring season did not differ between groups, and variations in blood measures of immunity were unrelated to URTI. [ABSTRACT FROM AUTHOR]

Weightlifting exercises, including the snatch and clean, are an important component in the strength and conditioning programs of athletes. The stop snatch and stop clean are variations that are effective for improving performance and technique. [ABSTRACT FROM AUTHOR]

Competing Interests: The authors have no financial relationships relevant to this article to disclose.

Introduction: Reserve Officers' Training Corps (ROTC) trainees are college students who complete military courses and participate in physical and tactical training under the direction of military Service Members assigned to ROTC programs to serve as faculty and staff at US colleges. ROTC trainees report musculoskeletal injuries (MSKIs) attributable to ROTC training in line with MSKI incidence in other training environments. However, concealment is prevalent, as 66% of MSKIs in ROTC go unreported. The current study investigated if a brief, online educational video could increase ROTC trainees' reporting intentions. In addition, we investigated if the message's source (i.e., peer or authority figure) affected reporting intentions., Materials and Methods: A repeated measures design was used to evaluate the impact of 2 MSKI educational interventions, one delivered by a high-achieving Army ROTC trainee (peer-led) and the other delivered by an Army ROTC battalion commander (authority-led), on MSKI reporting intentions, as compared to each other and a control intervention. Other than their personal introductions, both individuals had the same script addressing 4 areas: (1) MSKI prevalence in ROTC, (2) evidence of improved outcomes with early treatment, (3) encouraging injury reporting, and (4) addressing specific barriers and stigma beliefs previously identified in ROTC. The control condition consisted of a video demonstrating exercise technique with voiceover. A survey was developed to measure stigma regarding MSKI reporting and intentions to seek help for MSKI. ROTC trainees at 23 universities were invited to participate via an anonymous survey link. Participants completed the following using an online survey platform: (1) pre-intervention MSKI intentions scale, (2) randomly assigned intervention video, and (3) repeat MSKI intentions scale post-intervention. A two-way mixed, ANOVA was performed to assess interaction effects and main effects pre- and post-intervention., Results: One-hundred ROTC trainees (39% female; age = 21 ± 2 years, ROTC experience = 2 ± 1 years) completed the study. Participants were primarily from Army ROTC programs (72 Army, 14 Air Force, and 14 Naval). Pre-intervention survey scores (possible score range 8-56 with lower scores indicating greater intention to seek help): authority-led (n = 31) 20.3 ± 9.4, peer-led (n = 32) 21.8 ± 8.7, control (n = 37) 19.1 ± 10.1, total 20.3 ± 9.4. Post-intervention scores: authority-led 20.9 ± 11.2, peer-led 20.2 ± 10.0, control 17.3 ± 7.7, total 19.7 ± 9.3. There was no significant group*time interaction (F2,97 = 0.92, P = .403, η2partial = 0.02). There were no significant main effects for time (F1,97 = 1.461, P = .230, η2partial =0.015) or group (F2,97 = 1.08, P = .342, η2partial = 0.02)., Conclusions: Findings did not support the use of a single educational intervention video to influence MSKI help-seeking intentions of ROTC trainees. Intentions may already be ingrained such that a single intervention could not influence change. Previous research on concussion reporting indicates that concealment cultures may be systematic and indoctrination of concealment can influence one's reporting intentions. Our sample had already participated in ROTC for 2 years. Future research should evaluate if MSKI help-seeking intentions change over the course of ROTC participation, or even over a military career., (© The Association of Military Surgeons of the United States 2024. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site–for further information please contact journals.permissions@oup.com.)

Functional movement patterns are an important aspect of everyday life, and a growing area of interest for determining the risk of injury and performance ability. Police, military, and fire personnel often carry torso-borne loads that increase the demands on the body while performing occupational tasks. The purpose of this study was to compare movement screen results in both a loaded and unloaded condition to identify potential effects that torso-borne body armor load carriage may have on tactical performance. This provided objective data on the effects that external loads may have on functional movement patterns. Twenty-four physically active participants (11 males, 13 females) volunteered and completed the Fusionetics™ Movement Efficiency Test (FMET) in two conditions: loaded (wearing a 13.5 kg tactical vest) and unloaded, in a counterbalanced order. Participants were video recorded performing these movements and scored later. The overall scores, on a scale of 0 to 100, showed a large, statistically significant decline in functional movement pattern quality from the unloaded to the loaded condition (12.6±7.3 points, p<.001, d =1.8). In the subscales, statistically significant declines ( p <.001) were seen in the 2-leg squat ( d =0.8), push-ups ( d =1.1), shoulder movements ( d =2.1), and trunk movements ( d =0.9). There was no significant effect of load on the cervical movements or 1-leg squat. Overall, torso-borne body armor loading decreased functional movement pattern quality, suggesting the potential benefit of performing loaded movement screens on tactical athletes.

Background: Microsurgical techniques have revolutionized the field of reconstructive surgery and are the mainstay for complex soft tissue reconstruction. However, their limitations have promoted the development of viable alternatives. This article seeks to explore technologies that have the potential of revolutionizing microsurgical reconstruction as it is currently known, reflect on current and future vascularized composite allotransplantation (VCA) practices, as well as describe the basic science within emerging technologies and their potential translational applications., Methods: A literature review was performed of the technologies that may represent the future of microsurgery: vascularized tissue engineering (VCA) and flap-specific tissue engineering., Results: VCA has shown great promise and has already been employed in the clinical setting (especially in face and limb transplantation). Immunosuppression, logistics, cost, and regulatory pathways remain barriers to overcome to make it freely available. Vascularized and flap-specific tissue engineering remain a laboratory reality but have the potential to supersede VCA. The capability of creating an off-the-shelf free flap matching the required tissue, size, and shape is a significant advantage. However, these technologies are still at the early stage and require significant advancement before they can be translated into the clinical setting., Conclusion: VCA, vascularized tissue engineering, and flap-specific bioengineering represent possible avenues for the evolution of current microsurgical techniques. The next decade will elucidate which of these three strategies will evolve into a tangible translational option and hopefully bring a paradigm shift of reconstructive surgery., (© 2024 Society for Indian Hand Surgery and Micro Surgeons. Published by Elsevier B.V. All rights reserved.)

Background: Soft tissue defects with exposed avascular structures require reconstruction with well-vascularized tissues. Extensive research is ongoing to explore tissue engineered products that provide durable coverage. However, there is a lack of controlled and affordable testbeds in the preclinical setting to reflect this challenging clinical scenario. We aimed to address this gap in the literature and develop a feasible and easily reproducible model in rodents that reflects an avascular structure in the wound bed., Methods: We created 20 × 20 mm full thickness wounds on the dorsal skin of Lewis rats and secured 0.5-mm-thick silicone sheets of varying sizes to the wound bed. A 3D-printed wound frame was designed to isolate the wound environment. Skin graft and free flap survival along with exposure of the underlying silicone was assessed. Rats were followed for 4 weeks with weekly dressing changes and photography. Samples were retrieved at the endpoint for tissue viability and histologic analysis., Results: The total wound surface area was constant throughout the duration of the experiment in all groups and the wound frames were well tolerated. The portion of the skin graft without underlying silicone demonstrated integration with the underlying fascia and a histologically intact epidermis. Gradual necrosis of the portion of the skin graft overlying the silicone sheet was observed with varying sizes of the silicone sheet. When the size of the silicone sheet was reduced from 50% of the wound surface area, the portion surviving over the silicone sheet increased at the 4-week timepoint. The free flap provided complete coverage over the silicone sheet., Conclusion: We developed a novel model of rodent wound healing to maintain the same wound size and isolate the wound environment for up to 4 weeks. This model is clinically relevant to a complex wound with an avascular structure in the wound bed. Skin grafts failed to completely cover increasing sizes of the avascular structure, whereas the free flap was able to provide viable coverage. This cost-effective model will establish an easily reproducible platform to evaluate more complex bioengineered wound coverage solutions., Competing Interests: Conflicts of interest and sources of funding: None declared., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Military tactical athletes face the unique task of performing physically demanding occupational duties, often while wearing body armor. Forced vital capacity and forced expiratory volume measured using spirometry have been shown to decrease, while wearing plate-carrier style body armor, little is known about the comprehensive effects of wearing body armor on pulmonary function, including lung capacities. Further, the effects of loaded body armor vs. unloaded on pulmonary function are also unknown. Therefore, this study examined how loaded and unloaded body armor affects pulmonary function. Twelve college-aged males performed spirometry and plethysmography under three conditions (basic athletic attire [CNTL], unloaded plate carrier [UNL], and loaded plate carrier [LOAD]). Compared to CNTL, LOAD and UNL conditions significantly reduced functional residual capacity by 14% and 17%, respectively. Compared with CNTL, LOAD condition also showed a small but statistically significant lowered forced vital capacity (P = .02, d = 0.3), a 6% lower total lung capacity (P < .01, d = 0.5), and lowered maximal voluntary ventilation (P = .04, d = 0.4). A loaded plate-carrier style body armor exerts a restrictive effect on total lung capacity, and both loaded and unloaded body armor affects functional residual capacity, which could impact breathing mechanics during exercise. Resulting endurance performance decreases may need to be factored based on the style and loading of body armor, especially for longer-duration operations., (© The Association of Military Surgeons of the United States 2023. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Among service members, musculoskeletal injuries threaten military readiness and place a substantial burden on medical and financial resources. Emerging research suggests that service members regularly conceal injuries, especially in training environments. The Reserve Officers' Training Corps (ROTC) is a critical training environment for future U.S. military commissioned officers. Training activities expose cadets to a high risk of injury while in the ROTC. The purpose of this study was to explore injury-reporting behaviors in cadets and factors associated with injury concealment., Materials and Methods: We invited Army, Air Force, and Naval cadets from six host universities participating in officer training to complete an online, self-reported survey regarding injury reporting and concealment. Cadets answered questions about pain or injuries experienced during officer training. Survey questions pertained to an injury's anatomic location, onset, severity, functional limitations, and whether or not the injury had been reported. Cadets also selected factors that influenced the decision to report or conceal injuries from predetermined lists in a "choose any" fashion. A series of χ2 tests of independence compared the relationship between injury reporting and other injury characteristics for each individual injury., Results: One hundred fifty-nine cadets (121 Army, 26 Air Force, and 12 Naval) completed the survey. Eighty-five cadets disclosed a total of 219 injuries. Two-thirds of injuries (144/219) were concealed. Twenty-six percent of participants (22/85) reported all injuries, whereas the remainder (63/85, 74%) had at least one concealed injury. In relation to injury reporting/concealment, there was a weak association with injury onset (χ21 = 4.24, P = .04, V = 0.14), a moderate association with anatomic location (χ212 = 22.64, P = .03, V = 0.32), and relatively strong associations with injury severity (χ23 = 37.79, P < .001, V = 0.42) and functional limitations (χ23 = 42.91, P < .001, V = 0.44)., Conclusions: Two-thirds of injuries went unreported in this sample of ROTC cadets. Functional limitations, symptom severity, and injury onset may be the largest factors that influence the decision to report or conceal musculoskeletal injuries. This study establishes the foundation for researching injury reporting in cadets and adds to the existing military evidence on the topic., (© The Association of Military Surgeons of the United States 2023. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background:  Free tissue transfer to cover complex wounds with exposed critical structures results in donor-site morbidity. Perfusion decellularization and recellularization of vascularized composite tissues is an active area of research to fabricate complex constructs without a donor site. Sodium dodecyl sulfate (SDS)-based protocols remain the predominant choice for decellularization despite the deleterious effects on tissue ultrastructure and capillary networks. We aimed to develop an automated decellularization process and compare different SDS perfusion times to optimize the protocol., Methods:  A three-dimensional-printed closed-system bioreactor capable of continuously perfusing fluid through the vasculature was used for decellularization. The artery and vein of rat epigastric fasciocutaneous free flaps were cannulated and connected to the bioreactor. Protocols had varying durations of 1% SDS solution (3, 5, and 10 days) followed by 1 day of 1% Triton X-100 and 1 day of 1x phosphate-buffered saline. The residual DNA was quantified. Microarchitecture of the constructs was assessed with histology, and the vascular network was visualized for qualitative assessment., Results:  The structural integrity and the microarchitecture of the extracellular matrix was preserved in the 3- and 5-day SDS perfusion groups; however, the subcutaneous tissue of the 10-day protocol lost its structure. Collagen and elastin structures of the pedicle vessels were not compromised by the decellularization process. Five-day SDS exposure group had the least residual DNA content ( p  < 0.001). Across all protocols, skin consistently had twice as much residual DNA over the subcutaneous tissues., Conclusion:  A compact and integrated bioreactor can automate decellularization of free flaps to bioengineer regenerative constructs for future use in reconstruction of complex defects. A decellularization protocol with 5 days of 1% SDS exposure was the most successful to keep the residual DNA content at a minimum while preserving the structural integrity of the tissues., Competing Interests: None declared., (Thieme. All rights reserved.)

Background: Mechanical emulsification of adipose tissue to concentrate protein and stromal cell components (ie, nanofat) has gained considerable interest in clinical practice. Although the regenerative potential of nanofat has largely been used in aesthetic applications, these effects have considerable potential in reconstruction as well. Here, the authors investigated the therapeutic properties of nanofat injected directly into the denervated gastrocnemius after a sciatic nerve injury in Lewis rats., Methods: Muscle denervation was induced by transecting and immediately repairing the sciatic nerve. Inguinal and subcutaneous adipose was harvested from donor rodents, processed into nanofat, and then injected intramuscularly into the gastrocnemius. Gait analysis was performed weekly. Rodents were euthanized at 9 and 12 weeks, after which tetanic contraction force was measured, and gene expression, histology, and cytokine multiplexing were performed., Results: Intramuscular injection of nanofat significantly increased maximum tetanic force generation at 9 and 12 weeks. The forces of the nanofat-injected gastrocnemii were better correlated to their contralateral gastrocnemii relative to controls. Muscle repair-associated inflammatory gene expressions were significantly up-regulated in nanofat-injected gastrocnemii. Cytokines interleukin (IL)-1β, IL-18, vascular endothelial growth factor, granulocyte-macrophage colony-stimulating factor, and tissue inhibitor of metalloproteinase-1 were significantly higher in nanofat-injected gastrocnemii relative to control gastrocnemii, and the tetanic force was linearly and significantly correlated to IL-1β and IL-18 and their interacting effects., Conclusions: Intramuscular injection of emulsified adipose tissue (nanofat) significantly increased gastrocnemii contraction force after sciatic nerve injury, with prolonged reconstructive inflammation by means of CD68, inducible nitric oxide synthase, IL-1β, and IL-18 all being potential mechanisms for this recovery. This application could potentially increase the therapeutic breadth of nanofat to include muscular recovery after nerve injury., Clinical Relevance Statement: The authors' study investigates a clinically translatable therapy to mitigate muscle atrophy after nerve injury., (Copyright © 2022 by the American Society of Plastic Surgeons.)

Abstract: Hanes, CE, Schilling, BK, Mulvenon, SW, and Radzak, KN. Effects of fatigue on functional movement efficiency in physically active adults. J Strength Cond Res 36(9): 2448-2453, 2022-Functional movement tests to identify faulty movement patterns and compensations have become common place in sports medicine and sport performance; however, this testing is often performed in a rested state, despite athletes being often injured when in a state of neuromuscular fatigue. Therefore, the purpose of our study was to examine the effects of neuromuscular fatigue on a functional movement test in health, physically active adults. Twenty-five adults volunteered for the study (age = 23.3 ± 2.7 years, height = 168.2 ± 9.0 cm, body mass = 72.2 ± 12.5 kg). Subjects completed a prefatigue movement test, an aerobic exercise physically fatiguing protocol, and a postfatigue movement test. Scores were calculated according to compensations present during the tests. Prefatigue (45.1 ± 5.4) to postfatigue (39.9 ± 5.7) overall scores were significantly worse after the fatiguing protocol (p < 0.001, effect size [ES] = 0.9). Prefatigue to postfatigue scores for the 1-Leg Squat, Shoulder, and Cervical subtests were also significantly decreased (p = 0.005, ES = 0.7; p = 0.002, ES = 0.5; p = 0.016, ES = 0.7, respectively). Neuromuscular fatigue affected the functional movement test, demonstrated by a decrease in movement scores, in healthy adults. Clinicians may use the functional movement test to identify potential compensations while their patients are physically fatigued. Then clinicians can implement an injury prevention program to reduce the possible risk of injury., (Copyright © 2020 National Strength and Conditioning Association.)

Radiation-induced skin fibrosis (RISF) can result from a plethora of scenarios including cancer therapy, accidental exposure, or acts of terrorism. Radioactive beams can penetrate through the skin and affect the structures in their path including skin, muscles, and internal organs. Skin is the first structure to get exposed to radiation and is susceptible to develop chronic fibrosis, which is challenging to treat. Currently, limited treatment options show moderate efficacy in mitigating radiation-related skin fibrosis. A key factor hindering the development of effective countermeasures is the absence of a convenient and robust model that could allow for translation of the experimental findings to humans. Here, a robust and reproducible murine hind limb skin fibrosis model has been established for prophylactic and therapeutic evaluation of possible agents for functional and molecular recovery. The right hind limb was irradiated using a single dose of 40 (Gray) Gy to induce skin fibrosis. Subjects developed edema and dermatitis in the early stages proceeded by visible skin constriction. Irradiated limbs showed a significantly reduced limb range of motion in the following weeks. In late stages, acute side effects subsided, yet chronic fibrosis persisted. A gait index was performed as an additional functional assay, which demonstrated the development of functional impairment. These non-invasive methods demonstrated reliable measurements for tracing fibrosis progression, which is supported by histological analyses. The radiation dose, application, and post-irradiation analyses employed in this model offer a vigorous and reproducible method for studying radiation-induced skin fibrosis and testing the efficacy of therapeutical agents.

Abstract: Stone, BL, Ashley, JD, Skinner, RM, Polanco, JP, Walters, MT, Schilling, BK, and Kellawan, JM. Effects of a short-term heat acclimation protocol in elite amateur boxers. J Strength Cond Res 36(7): 1966-1971, 2022-Boxing requires proficient technical and tactical skills coupled with high levels of physiological capacity. Although heat and humidity negatively affect acute exercise performance, short-term exercise training in hot and humid environments can lead to physiological adaptations that enhance exercise performance in both hot and thermoneutral conditions. In highly trained endurance athletes, exercise-induced acclimation can occur in as little as 5 days (known as short-term heat acclimation [STHA]). However, the impact of a 5-day heat acclimation (5-DayHA) in combat athletes, such as elite amateur boxers, is unknown. The aim of the present investigation was to determine whether a 5-DayHA improves aerobic performance in a thermoneutral environment and causes positive physiological adaptations in elite boxers. Seven elite amateur boxers underwent a 5-DayHA protocol, consisting of 60-minute exercise sessions in an environmental chamber at 32 °C and 70% relative humidity. Repeat sprint test (RST) evaluated aerobic performance in a thermoneutral environment 24 hours before and after the 5-DayHA. Presession and postsession hydration status (urine specific gravity) and body mass were assessed. After a 5-DayHA period, boxers significantly improved RST performance (13 ± 7 to 19 ± 7 sprints, d = 0.92, p = 0.03) but not pre-exercise hydration status (1.02 ± 0.01 to 1.01 ± 0.01, d = 0.82, p = 0.07). Therefore, these findings suggest 5-DayHA enhances aerobic performance in elite-level amateur boxers and may provide a viable training option for elite combat athletes., (Copyright © 2022 National Strength and Conditioning Association.)

Indoor sport rock climbing has been increasing in popularity both recreationally and competitively. Despite this increase in popularity, the physiological responses to sport climbing as an exercise to specific muscle groups are not well defined. The purpose of this study was to quantify the change in handgrip strength over a 30-minute bout of continuous climbing, specifically in intermediate-level sport climbers. Ten intermediate rock climbers (age = 27 ± 2 years; climbing experience: 7.3 ± 1.5 years) completed baseline handgrip strength and forearm girth measurements. Each participant ascended one of two 5.9 difficulty routes as many times as possible in 30 minutes. After each ascent, heart rate was obtained, and handgrip strength and forearm girth were measured. Data were analyzed using repeated-measures ANOVA with significance set at α < 0.05. Dominant arm handgrip strength decreased by 22%, and non-dominant handgrip strength reduced by 23%. Dominant and non-dominant forearm girth increased by 4.5% and 4.4%, respectively. Weak but significant negative correlations were observed between handgrip strength and forearm girth in dominant ( r = -0.311, p = 0.001) and non-dominant limbs ( r = -.491, p = 0.001). These results indicate a relationship between increased forearm girth and decreases in muscular strength. Since handgrip strength decreases substantially during a 30-min climb in intermediate rock climbers, this population would be advised to carefully monitor recovery time between bouts.

Introduction: Cadets participating in Reserve Officers' Training Corp (ROTC) at US universities undergo both Army Physical Fitness Test (APFT) and Occupational Physical Assessment Test (OPAT) evaluations prior to commissioning. The current study examined the relationship between ROTC physical training (PT) attendance and performance in the APFT and OPAT, and characterised physical activity of cadets outside of PT., Methods: Twenty-six cadets' (21 males; age=20.81±2.48 years; height=171.16±8.62 cm; body mass=75.49±13.17 kg; body mass index=25.68±3.37 kg/m 2 ) PT attendance, and diagnostic (week 1) and record (week 13) OPAT and APFT scores were documented. Paired samples t-tests evaluated differences in APFT and OPAT scores between the diagnostic and record tests. Pearson correlations were utilised to determine if a relationship existed between PT attendance and test performance. Participating cadets also completed monthly self-reported physical activity questionnaire (September, October, November); findings were reported using descriptive statistics., Results: Cadets attended 87% of PT sessions between OPAT administrations and 85% between APFT administrations. Cadets significantly improved the following test components: standing long jump (p=0.034), seated power throw (p=0.029), shuttle run (p=0.005), sit-ups (p=0.003) and 2-mile run (p=0.045). A significant, positive correlation was found between PT attendance and APFT sit-ups improvements (r=0.473, p=0.015). Cadets' frequently reported additional physical activity days per week (range: 2.8-3.1 aerobic, 3.2-3.8 strength/power, 2.9-3.2 core strength/endurance)., Conclusions: Regular participation in a single semester of ROTC PT was found to significantly increase cadets' scores in some, but not all, components of the APFT and OPAT. Self-reported physical activity results indicate that cadets regularly train outside of organised PT., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Peripheral nerve injury and the associated muscle atrophy has an estimated annual healthcare burden of $150 billion dollars in the United States. When considering the total annual health-related spending of $3.5 trillion, these pathologies alone occupy about 4.3%. The prevalence of these ailments is rooted, at least in part, in the lack of specific preventative therapies that can be administered to muscle while it remains in the denervated state. To address this, skeletal muscle-derived ECM (skECM) was injected directly in denervated muscle with postoperative analysis performed at 20 weeks, including gait analysis, force production, cytokine quantification, and histological analysis. skECM was shown to be superior against non-injected muscle controls showing no difference in contraction force to uninjured muscle at 20 weeks. Cytokines IL-1β, IL-18, and IFNγ appeared to mediate regeneration with statistical regression implicating these cytokines as strong predictors of muscle contraction, showing significant linear correlation., Competing Interests: Declaration of conflicting interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2021.)

Fresh whole blood transfusion is advantageous when operating far-forward for both its availability and its physiological advantages over component therapy. However, the far-forward environment may place high physical performance demands on the donor immediately after donation. The aim of this paper was to briefly review the current literature on the effects of whole blood donation on a male donor's immediate physical performance after a standard donation volume of one unit (~450mL). Studies demonstrate reductions in peak volume of oxygen (VO2peak) of ~4% to 15% and time to exhaustion (TTE) of ~10% to 19% in the first 24 to 48 hours after donation. Anaerobic or cognitive performance has not been shown to decrease, but data on these parameters are limited. Donor physical performance decrements after a standard 450mL donation are minimal and may be mitigated through proper exercise training because training status may positively affect many variables that blood donation temporarily attenuates., (2021.)

Background: Gender bias and sexual misconduct continue to pervade medicine. The authors hypothesize that gender bias and sexual misconduct disproportionately and negatively affect female plastic surgery trainees., Methods: A national survey of plastic surgery trainees (2018 to 2019) was conducted using previously validated sexual harassment surveys adapted for relevance to plastic surgery. Respondents were queried about experiences with workplace gender bias and harassment; personal and professional impact; and reporting practices. Analyses included chi-square, logistic regression, and analysis of variance. Significance was accepted for values of p < 0.05., Results: There were 236 responses (115 female respondents; 20.1 percent response rate). Most respondents were Caucasian (Asian/Pacific Islander, n = 34) residents (n = 123). The feeling of hindrance to career advancement was greater for women, by 10-fold (p < 0.001), and increased with age (p = 0.046). Women felt uncomfortable challenging attitudes regarding gender inequality (p < 0.001), regardless of training levels (p = 0.670) or race (p = 0.300). Gender bias diminished female trainees' career goals/ambition (p < 0.001). Women were more likely to experience sexual harassment, in the form of jokes (p = 0.003) and comments about their body or sexuality (p = 0.014). Respondents reported the majority of perpetrators of harassment to be attending physicians (30 percent) and other trainees (37 percent). Most common reasons to not report incidents included "futility" (29 percent) and "fear" (20 percent). Women experienced at least three symptoms of depression/anxiety, significantly higher than men (p = 0.001)., Conclusions: Gender bias and sexual misconduct negatively affect female trainees' attitudes toward their career. Two-thirds of cases of sexual harassment originate from other physicians. Minority trainees are less prepared to address transgressions and more likely to experience sexual coercion. Trainees perceive a culture nonconducive to reporting. These findings can guide changes and discussions surrounding workplace culture in plastic surgery training., (Copyright © 2021 by the American Society of Plastic Surgeons.)

Severe peripheral nerve injuries have devastating consequences on the quality of life in affected patients, and they represent a significant unmet medical need. Destruction of nerve fibers results in denervation of targeted muscles, which, subsequently, undergo progressive atrophy and loss of function. Timely restoration of neural innervation to muscle fibers is crucial to the preservation of muscle homeostasis and function. The goal of this study was to evaluate the impact of addition of adipose stem cells (ASCs) to polycaprolactone (PCL) nerve conduit guides on peripheral nerve repair and functional muscle recovery in the setting of a critical size nerve defect. To this end, peripheral nerve injury was created by surgically ablating 6 mm of the common peroneal nerve in a rat model. A PCL nerve guide, filled with ASCs and/or poloxamer hydrogel, was sutured to the nerve ends. Negative and positive controls included nerve ablation only (no repair), and reversed polarity autograft nerve implant, respectively. Tibialis anterior (TA) muscle function was assessed at 4, 8, and 12 weeks postinjury, and nerve and muscle tissue was retrieved at the 12-week terminal time point. Inclusion of ASCs in the PCL nerve guide elicited statistically significant time-dependent increases in functional recovery (contraction) after denervation; ∼25% higher than observed in acellular (poloxamer-filled) implants and indistinguishable from autograft implants, respectively, at 12 weeks postinjury ( p  < 0.05, n  = 7-8 in each group). Analysis of single muscle fiber cross-sectional area (CSA) revealed that ASC-based treatment of nerve injury provided a better recapitulation of the overall distribution of muscle fiber CSAs observed in the contralateral TA muscle of uninjured limbs. In addition, the presence of ASCs was associated with improved features of re-innervation distal to the defect, with respect to neurofilament and S100 (Schwann cell marker) expression. In conclusion, these initial studies indicate significant benefits of inclusion of ASCs to the rate and magnitude of both peripheral nerve regeneration and functional recovery of muscle contraction, to levels equivalent to autograft implantation. These findings have important implications to improved nerve repair, and they provide input for future work directed to restoration of nerve and muscle function after polytraumatic injury. Impact Statement This works explores the application of adipose stem cells (ASCs) for peripheral nerve regeneration in a rat model. Herein, we demonstrate that the addition of ASCs in poloxamer-filled PCL nerve guide conduits impacts nerve regeneration and recovery of muscle function, to levels equivalent to autograft implantation, which is considered to be the current gold standard treatment. This study builds on the importance of a timely restoration of innervation to muscle fibers for preservation of muscle homeostasis, and it will provide input for future work aiming at restoring nerve and muscle function after polytraumatic injury.

Study Objective: Throughout the coronavirus disease 2019 pandemic, many emergency departments have been using passive protective enclosures ("intubation boxes") during intubation. The effectiveness of these enclosures remains uncertain. We sought to quantify their ability to contain aerosols using industry standard test protocols., Methods: We tested a commercially available passive protective enclosure representing the most common design and compared this with a modified enclosure that incorporated a vacuum system for active air filtration during simulated intubations and negative-pressure isolation. We evaluated the enclosures by using the same 3 tests air filtration experts use to certify class I biosafety cabinets: visual smoke pattern analysis using neutrally buoyant smoke, aerosol leak testing using a test aerosol that mimics the size of virus-containing particulates, and air velocity measurements., Results: Qualitative evaluation revealed smoke escaping from all passive enclosure openings. Aerosol leak testing demonstrated elevated particle concentrations outside the enclosure during simulated intubations. In contrast, vacuum-filter-equipped enclosures fully contained the visible smoke and test aerosol to standards consistent with class I biosafety cabinet certification., Conclusion: Passive enclosures for intubation failed to contain aerosols, but the addition of a vacuum and active air filtration reduced aerosol spread during simulated intubation and patient isolation., (Copyright © 2020. Published by Elsevier Inc.)

Stone, BL and Schilling, BK. Neuromuscular fatigue in pitchers across a collegiate baseball season. J Strength Cond Res 34(7): 1933-1937, 2020-Neuromuscular fatigue in baseball pitchers has become an important aspect of injury risk. It is imperative to understand how fatigue is manifested to enhance resiliency and mitigate injury risk. Secondarily, collecting data on neuromuscular characteristics of baseball pitchers provides a framework to address these concerns. Using the countermovement jump, this study observed neuromuscular performance during the preseason, midseason, and postseason of a collegiate baseball season with college baseball pitchers. No statistically significant changes were noted in any of the main variables at any testing timepoint (p > 0.05). However, several variables, including concentric mean force (ConMF, d = 0.59) and concentric peak force (ConPF, d = 0.59) in addition to eccentric mean force (EccMF, d = 0.54) and eccentric mean power (EccMP, d = -0.66), displayed moderate effects from preseason testing to midseason testing. Furthermore, jump height displayed a large negative effect from preseason to midseason (d = -0.89). Secondarily, descriptive data for both concentric and eccentric variables were also determined from the present findings. There were moderate changes in neuromuscular fatigue in Division I collegiate pitchers across a competitive season and has provided descriptive data for neuromuscular characteristics in collegiate baseball pitchers.

Tissue decellularization for generating extracellular matrices has become a staple of regenerative medicine in the recent decades, extending from the research setting to clinical usage. Although methods and protocols for tissue decellularization are abundant throughout the literature, they can be time intensive and typically require specific overhead in terms of equipment. To reduce these barriers to entry, a functional and reproducible prototype of a tissue infusion/perfusion device (TIPD) has been designed and fabricated using three-dimensional printed parts in conjunction with commercially available components. This TIPD forms a system composed of two peristaltic pumps, two 3-way valves, and a chamber in which tissue is contained, and is controlled by user-customizable software. To increase repeatability among decellularization protocols, an automation function has been integrated into the software, which is able to specify fluid flow rates and define specific valve locations enabling selection of solutions to be introduced into a scaffold over the course of a decellularization process. The prototype has been tested for proof of concept through infusion and perfusion decellularization of skeletal muscle and intact kidneys, respectively, and has shown successful removal of cellular content while maintaining an intact ultrastructure. In an effort to increase the reproducibility of experimental designs and to promote an open source hardware initiative in the field of tissue engineering, a novel device was conceptualized and prototyped with printable part files made available for its fabrication in tandem with instructions for assembly. Impact Statement Repeatable methods for decellularization are essential for achieving consistent substrates between batches, laboratories, and facilities. To meet this end, an automatable tissue infusion/perfusion device composed of three-dimensional printed parts and commercially available components has been prototyped and tested. Materials and instructions for its assembly have been made available in an effort to reduce variability among equipment as well as to provide a platform on which to iterate open-source hardware in tissue engineering.

Biomaterials derived from human adipose extracellular matrix have shown promise in vitro and in animal studies as an off-the-shelf adipogenic matrix for sustained volume replacement. Herein, we report the results of a randomized prospective study conducted with allograft adipose matrix (AAM) grafted into the pannus of presurgical abdominoplasty patients 3 or 6 months before scheduled surgery. This is the first report of a longitudinal histologic analysis of AAM in clinical use., Methods: Ten healthy patients undergoing elective abdominoplasty were recruited to receive AAM before surgery. Enrolled subjects were randomized into either a 3-month follow-up cohort or a 6-month follow-up cohort. Subjects were monitored for adverse events associated with AAM grafting in addition to undergoing serial biopsy. Following surgical excision of the pannus, representative samples from the AAM surgical sites were stained and evaluated with hematoxylin and eosin for tissue morphology, Masson's trichrome for collagen, and perilipin for adipocytes., Results: All subjects tolerated AAM with no severe adverse events reported. At 3 months following implantation, AAM remained visible within the confines of the subjects' native surrounding adipose tissue with sparse adipocytes apparent within the matrix. By 6 months, AAM had remodeled and was primarily composed of perilipin-positive adipocytes. Histologic analysis confirmed tissue remodeling (hematoxylin and eosin), adipogenesis (perilipin), and angiogenesis (Masson's trichrome) occurred with the presence of AAM., Conclusions: AAM is a safe, allogeneic, off-the-shelf regenerative matrix that is adipogenic and noninflammatory and promotes angiogenesis., (Copyright © 2020 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.)

Severe injuries to peripheral nerves are challenging to repair. Standard-of-care treatment for nerve gaps >2 to 3 centimeters is autografting; however, autografting can result in neuroma formation, loss of sensory function at the donor site, and increased operative time. To address the need for a synthetic nerve conduit to treat large nerve gaps, we investigated a biodegradable poly(caprolactone) (PCL) conduit with embedded double-walled polymeric microspheres encapsulating glial cell line-derived neurotrophic factor (GDNF) capable of providing a sustained release of GDNF for >50 days in a 5-centimeter nerve defect in a rhesus macaque model. The GDNF-eluting conduit (PCL/GDNF) was compared to a median nerve autograft and a PCL conduit containing empty microspheres (PCL/Empty). Functional testing demonstrated similar functional recovery between the PCL/GDNF-treated group (75.64 ± 10.28%) and the autograft-treated group (77.49 ± 19.28%); both groups were statistically improved compared to PCL/Empty-treated group (44.95 ± 26.94%). Nerve conduction velocity 1 year after surgery was increased in the PCL/GDNF-treated macaques (31.41 ± 15.34 meters/second) compared to autograft (25.45 ± 3.96 meters/second) and PCL/Empty (12.60 ± 3.89 meters/second) treatment. Histological analyses included assessment of Schwann cell presence, myelination of axons, nerve fiber density, and g -ratio. PCL/GDNF group exhibited a statistically greater average area occupied by individual Schwann cells at the distal nerve (11.60 ± 33.01 μm 2 ) compared to autograft (4.62 ± 3.99 μm 2 ) and PCL/Empty (4.52 ± 5.16 μm 2 ) treatment groups. This study demonstrates the efficacious bridging of a long peripheral nerve gap in a nonhuman primate model using an acellular, biodegradable nerve conduit., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Background: Plastic surgery trainees who wish to start a family face challenges. This is the first study to collect data directly from residents and fellows to understand issues surrounding childbearing and to propose solutions., Methods: Following institutional review board approval, an anonymous survey was distributed to all current plastic surgery residents and fellows in the United States. Data regarding demographics, obstetrical complications, parental leave, breastfeeding, and use of assisted reproductive technology were collected., Results: The survey was completed by 307 trainees, for a resident response rate of 27.0 percent. Mean age of the respondents was 31.7 ± 3.8 years, 58.6 percent were married, and 35.3 percent reported at least one pregnancy for themselves or for their partner. Both male (67.4 percent) and female (76.5 percent) respondents intentionally postponed having children because of career. Women were significantly more likely to report negative stigma attached to pregnancy (70.4 percent versus 51.1 percent; p = 0.003) and plan to delay childbearing until after training. Fifty-six percent of female trainees reported an obstetrical complication. Assisted reproductive technology was used by 19.6 percent of trainees. Mean maternity leave was 5.5 weeks, with 44.4 percent taking less than 6 weeks. Mean paternity leave was 1.2 weeks. Sixty-two percent of women and 51.4 percent of men reported dissatisfaction with leave. Sixty-one percent of female trainees breastfed for 6 months and 19.5 percent continued for 12 months. Lactation facilities were available near operating rooms for 29.4 percent of respondents., Conclusions: Plastic surgery training may negatively impact fertility, obstetrical health, and breastfeeding practices. The data presented in this article provide the groundwork for identifying areas of concern and potential solutions.

Introduction: Injuries to peripheral nerves cause distal muscle atrophy. The effects of adipose-derived stem cell (ASC) injections into a muscle after injury were examined., Methods: A 1.5 cm defect in the rat sciatic nerve was created, resulting in gastrocnemius muscle atrophy. The nerve defect was repaired with autograft; DiR-labeled ASCs were injected into the gastrocnemius immediately postoperatively. Quantitation of gross musculature and muscle fiber area, cell survival, fibrosis, lipid deposition, inflammation, and reconstructive responses were investigated., Results: ASCs were identified in the muscle at 6 weeks, where injections showed increased muscle mass percentage retained, larger average fiber area, and less overall lipid content accumulated throughout the musculature. Muscles having received ASCs showed increased presence of interlukin-10 and Ki67, and decreased inducible nitric oxide synthase (iNOS)., Discussion: This investigation is suggestive that an ASC injection into denervated muscle post-operatively is able to delay the onset of atrophy. Muscle Nerve 59:603-603, 2019., (© 2019 Wiley Periodicals, Inc.)

Background: Adipose tissue reaches cellular stasis after puberty, leaving adipocytes unable to significantly expand or renew under normal physiologic conditions. This is problematic in progressive lipodystrophies, in instances of scarring, and in soft-tissue damage resulting from lumpectomy and traumatic deformities, because adipose tissue will not self-renew once damaged. This yields significant clinical necessity for an off-the-shelf de novo soft-tissue replacement mechanism., Methods: A process comprising separate steps of removing lipid and cellular materials from adipose tissue has been developed, creating an ambient temperature-stable allograft adipose matrix. Growth factors and matrix proteins relevant to angiogenesis and adipogenesis were identified by enzyme-linked immunosorbent assay and immunohistochemistry, and subcutaneous soft-tissue integration of the allograft adipose matrix was investigated in vivo in both the athymic mouse and the dorsum of the human wrist., Results: Allograft adipose matrix maintained structural components and endogenous growth factors. In vitro, adipose-derived stem cells cultured on allograft adipose matrix underwent adipogenesis in the absence of media-based cues. In vivo, animal modeling showed vasculature formation followed by perilipin A-positive tissue segments. Allograft adipose matrix maintained soft-tissue volume in the dorsal wrist in a 4-month investigation with no severe adverse events, becoming palpably consistent with subcutaneous adipose., Conclusions: Subcutaneous implantation of allograft adipose matrix laden with retained angiogenic and adipogenic factors served as an inductive scaffold for sustaining adipogenesis. Tissue incorporation assessed histologically from both the subcutaneous injection site of the athymic nude mouse over 6 months and human dorsal wrist presented adipocyte morphology residing within the injected scaffold.

This study sought to identify kinetic and electromyographic subphase characteristics distinguishing good from poor jumpers during countermovement vertical jumps (CMVJs), as defined by the reactive strength index (RSI, CMVJ displacement divided by jump time; cutoff = 0.46 m·s -1 ). A total of 15 men (1.8 [0.6] m, 84.5 [8.5] kg, 24 [2] y) were stratified by RSI into good (n = 6; RSI = 0.57 [0.07] m·s -1 ) and poor (n = 9; RSI = 0.39 [0.06] m·s -1 ) performance groups. The following variables were compared between groups using independent t tests (α = .05) and Cohen's d effect sizes (d ≥ 0.8, large): jump height, propulsive impulse, eccentric rate of force development, and jump time, unloading, eccentric, and concentric subphase times, and average electromyographic amplitudes of 8 lower extremity muscles. Compared with the poor RSI group, the good RSI group exhibited a greater, though not statistically different CMVJ displacement (d = 1.07, P = .06). In addition, the good RSI group exhibited a significantly greater propulsive impulse (P = .04, d = 1.27) and a significantly more rapid unloading subphase (P = .04, d = 1.08). No other significant or noteworthy differences were detected. Enhanced RSI appears related to a quicker unloading phase, allowing a greater portion of the total jumping phase to be utilized generating positive net force. Poor jumpers should aim to use unloading strategies that emphasize quickness to enhance RSI during CMVJ.

Swearingen, JT, Weiss, LW, Smith, WA, Stephenson, MD, and Schilling, BK. Potential utility of a loaded treadmill protocol for tactical athletes. J Strength Cond Res 32(3): 610-616, 2018-Aerobic capacity is an important variable for tactical athletes, with V[Combining Dot Above]O2max being the most direct way of estimating it in a laboratory setting. A mode-specific protocol involving fixed-weight, torso-borne loads was assessed in the current study. On 4 separate days, 15 men (age 22.1 ± 2.7 years, mass 85.1 ± 10.6 kg, height 179.0 ± 7.7 cm) performed a weighted treadmill walking protocol (2 trials) and a nonweighted treadmill running protocol (2 trials). Both the weighted and nonweighted protocols were reliable, with intraclass correlation coefficient values of 0.79 and 0.87, respectively. V[Combining Dot Above]O2peak values from both protocols were highly correlated (r = 0.90, p < 0.01). However, V[Combining Dot Above]O2peak was higher during the nonweighted protocol (t = 7.547, d = 2.47, p < 0.01). Work rate was calculated for both the last completed stage and stage during which participants reached fatigue. Work rates for both protocols on the last completed stage were similar (t = 1.44, d = 0.83, p = 0.17), although the work rate for the final attempted stage was greater for the weighted-walking protocol (t = 5.85, d = 3.60, p < 0.01). These data suggest a weighted-walking V[Combining Dot Above]O2peak that is highly associated with a running V[Combining Dot Above]O2peak. This test may be applied to those who routinely perform torso-borne load carriage, such as tactical athletes. Future weighted-walking protocols should seek achieve higher resolution, especially near the end stage of the test where subjects reach volitional fatigue. Large increases in work rate may not be feasible at the end stages of the test.

Research has focused on the effects of acute strike pattern modifications on lower extremity joint stiffness and running economy (RE). Strike pattern modifications on running biomechanics have mostly been studied while runners complete short running bouts. This study examined the effects of an imposed forefoot strike (FFS) on RE and ankle and knee joint stiffness before and after a long run in habitual rearfoot strike (RFS) runners. Joint kinetics and RE were collected before and after a long run. Sagittal joint kinetics were computed from kinematic and ground reaction force data that were collected during over-ground running trials in 13 male runners. RE was measured during treadmill running. Knee flexion range of motion, knee extensor moment and ankle joint stiffness were lower while plantarflexor moment and knee joint stiffness were greater during imposed FFS compared with RFS. The long run did not influence the difference in ankle and knee joint stiffness between strike patterns. Runners were more economical during RFS than imposed FFS and RE was not influenced by the long run. These findings suggest that using a FFS pattern towards the end of a long run may not be mechanically or metabolically beneficial for well-trained male RFS runners.

Fry, AC, Housh, TJ, Cramer, JB, Weir, JP, Beck, TW, Schilling, BK, Miller, JD, and Nicoll, JX. Noninvasive assessment of skeletal muscle myosin heavy chain expression in trained and untrained men. J Strength Cond Res 31(9): 2355-2362, 2017-Numerous conditions and types of physical activity (e.g., exercise, aging, and muscle-related diseases) can influence muscle fiber types and the proteins expressed. To date, muscle fibers can only be characterized by actually obtaining a tissue sample using the invasive muscle biopsy procedure. Mechanomyography (MMG) is the assessment of the vibration properties of contracting skeletal muscle and has been proposed as a possible noninvasive method for muscle fiber analysis. Therefore, the purpose of this project was to examine the feasibility of using MMG and muscle performance measures to noninvasively assess muscle fiber characteristics. Fifteen men (5 endurance-trained, 5 weight-trained, and 5 sedentary) provided muscle samples from their vastus lateralis muscle. These samples were analyzed for relative myosin heavy chain (MHC) protein expression, which is highly correlated with % muscle fiber type areas. Additionally, each subject performed several muscle performance tests, and MMG of the quadriceps was assessed during a knee extension exercise. Multiple regression was used to develop prediction equations for determining relative muscle content of MHC types I, IIa, and IIx. A combination of MMG and knee extension performance variables estimated types I, IIa, and IIx MHCs with approximately 80% accuracy. Although preliminary, these data suggest that muscle performance tests in addition to MMG assessments during a simple muscle performance task (knee extension) can be used to estimate muscle fiber type composition in a healthy male population. Such methods could ultimately be used to noninvasively monitor muscle health and fitness.

Runners often experience delayed onset muscle soreness (DOMS), especially of the knee extensors, following prolonged running. Sagittal knee joint biomechanics are altered in the presence of knee extensor DOMS but it is unclear how muscle soreness affects lower limb biomechanics in other planes of motion. The purpose of this study was to assess the effects of knee extensor DOMS on three-dimensional (3D) lower limb biomechanics during running. Thirty-three healthy men (25.8 ± 6.8 years; 84.1 ± 9.2 kg; 1.77 ± 0.07 m) completed an isolated eccentric knee extensor damaging protocol to elicit DOMS. Biomechanics of over-ground running at a set speed of 3.35 m s -1 ±5% were measured before eccentric exercise (baseline) and, 24 h and 48 h following exercise in the presence of knee extensor DOMS. Knee flexion ROM was reduced at 48 h (P = 0.01; d = 0.26), and peak knee extensor moment was reduced at 24 h (P = 0.001; d = 0.49) and 48 h (P < 0.001; d = 0.68) compared to baseline. Frontal and transverse plane biomechanics were unaffected by the presence of DOMS (P > 0.05). Peak positive ankle and knee joint powers and, peak negative knee joint power were all reduced from baseline to 24 h and 48 h (P < 0.05). These findings suggest that knee extensor DOMS greatly influences sagittal knee joint angular kinetics and, reduces sagittal power production at the ankle joint. However, knee extensor DOMS does not affect frontal and transverse plane lower limb joint biomechanics during running.

Background: Bradykinesia and reduced neuromuscular force exist in Parkinson disease. The interpolated twitch technique has been used to evaluate central versus peripheral manifestations of neuromuscular strength in healthy, aging, and athletic populations, as well as moderate to advanced Parkinson disease, but this method has not been used in mild Parkinson disease. This study aimed to evaluate quadriceps femoris rate of force development and quantify potential central and peripheral activation deficits in individuals with Parkinson disease., Methods: Nine persons with mild Parkinson Disease (Hoehn & Yahr≤2, Unified Parkinson Disease Rating Scale total score=mean 19.1 (SD 5.0)) and eight age-matched controls were recruited in a cross-sectional investigation. Quadriceps femoris voluntary and stimulated maximal force and rate of force development were evaluated using the interpolated twitch technique., Findings: Thirteen participants satisfactorily completed the protocol. Individuals with early Parkinson disease (n=7) had significantly slower voluntary rate of force development (p=0.008; d=1.97) and rate of force development ratio (p=0.004; d=2.18) than controls (n=6). No significant differences were found between groups for all other variables., Interpretations: Persons with mild-to-moderate Parkinson disease display disparities in rate of force development, even without deficits in maximal force. The inability to produce force at a rate comparable to controls is likely a downstream effect of central dysfunction of the motor pathway in Parkinson disease., (Copyright © 2017. Published by Elsevier Ltd.)

Understanding the effects of training in different footwear on sporting performance would be useful to coaches and athletes., Purpose: This study compared the effects of computerized agility training using 3 types of footwear on change-of-direction and balance performance in young adults., Method: Thirty recreationally active young adults (M age  = 22.8 ± 3.1 years; M height  = 1.71 ± 0.7 m; M bodymass  = 73.4 ± 10.3 kg) were randomly assigned to a 6-week computerized agility training intervention in 1 of 3 footwear groups (n = 10/group): barefoot, minimal footwear, or traditional shoes. Participants had no previous barefoot or minimal-footwear training experience. Dependent variables included change-of-direction test time to completion, Star Excursion Balance Test, and single-leg stability evaluation. Testing was performed at the start of the training program, after 2 weeks, after 4 weeks, and at the end of the training program., Results: No group or time interactions were found for any of the dependent variables. Time main effects were observed for the performance measures of change of direction, Star Excursion, and single-leg-with-eyes-open stability evaluation. Participants improved in all 3 tests as early as 2 weeks into the intervention, with improvements continuing through the entire 6-week intervention., Conclusions: The lack of interaction and footwear effects suggests that agility and balance improvements during foot agility training are independent of footwear in a recreationally active young-adult population. Computerized agility training improves change-of-direction and balance performance within 2 weeks of training implementation. Future studies should consider footwear training effects in different populations, including frail older adults and athletes.

Caia, J, Weiss, LW, Chiu, LZF, Schilling, BK, Paquette, MR, and Relyea, GE. Do lower-body dimensions and body composition explain vertical jump ability? J Strength Cond Res 30(11): 3073-3083, 2016-Vertical jump (VJ) capability is integral to the level of success attained by individuals participating in numerous sport and physical activities. Knowledge of factors related to jump performance may help with talent identification and/or optimizing training prescription. Although myriad variables are likely related to VJ, this study focused on determining if various lower-body dimensions and/or body composition would explain some of the variability in performance. Selected anthropometric dimensions were obtained from 50 university students (25 men and 25 women) on 2 occasions separated by 48 or 72 hours. Estimated body fat percentage (BF%), height, body weight, hip width, pelvic width, bilateral quadriceps angle (Q-angle), and bilateral longitudinal dimensions of the feet, leg, thigh, and lower limb were obtained. Additionally, participants completed countermovement VJs. Analysis showed BF% to have the highest correlation with countermovement VJ displacement (r = -0.76, p < 0.001). When examining lower-body dimensions, right-side Q-angle displayed the strongest association with countermovement VJ displacement (r = -0.58, p < 0.001). Regression analysis revealed that 2 different pairs of variables accounted for the greatest variation (66%) in VJ: (a) BF% and sex and (b) BF% and body weight. Regression models involving BF% and lower-body dimensions explained up to 61% of the variance observed in VJ. Although the variance explained by BF% may be increased by using several lower-body dimensions, either sex identification or body weight explains comparatively more. Therefore, these data suggest that the lower-body dimensions measured herein have limited utility in explaining VJ performance.

Davis, MR, Easter, RL, Carlock, JM, Weiss, LW, Longo, EA, Smith, LM, Dawes, JJ, and Schilling, BK. Self-reported physical tasks and exercise training in Special Weapons and Tactics (SWAT) teams. J Strength Cond Res 30(11): 3242-3248, 2016-Little research has been done examining the most physically demanding tasks a SWAT officer may perform in the line of duty. Our objective was to analyze the rankings of tasks by SWAT officers based on frequency, difficulty, and importance and assess if training is addressing traits needed for successful task completion. A survey was designed using Qualtrics (Qualtrics Labs Inc). The survey had a demographics section, performance section, and training section. Officers were contacted by phone or e-mail and asked about interest in participating. Officers who agreed were sent the survey. Our results found a strong correlation between frequency of task and importance (r = 0.69, p = 0.001), and a moderate correlation was found between task difficulty and importance (r = 0.37, p = 0.005). Task rankings were averaged across the 3 domains to assess "overall" importance, and the top 3 tasks were assessed for necessary traits for successful performance. Power and strength were determined to be the most important traits for successful performance. Officers ranked the top 2 focuses of their training program in the training section as stamina/muscular endurance and cardiovascular/respiratory endurance. Training programs for SWAT officers should be developed to improve performance of the tasks with the highest "overall" importance. Therefore, a training program should emphasize strength and power improvements while not neglecting other measures of fitness.

Caia, J, Weiss, LW, Chiu, LZF, Schilling, BK, and Paquette, MR. Consistency of lower-body dimensions using surface landmarks and simple measurement tools. J Strength Cond Res 30(9): 2600-2608, 2016-Body dimensions may influence various types of physical performance. This study was designed to establish the reliability and precision of bilateral lower-body dimensions using surface anatomic landmarks and either sliding calipers or goniometry. Fifty university students (25 men and 25 women) were measured on 2 separate occasions separated by 48 or 72 hours. A small digital caliper was used to acquire longitudinal dimensions of the feet, whereas a larger broad-blade caliper was used to measure lower-limb, hip, and pelvic dimensions. Quadriceps angle (Q-angle) was determined through surface goniometry. Data for all foot and lower-limb dimensions were both reliable and precise (intraclass correlation coefficient (ICC) ≥0.72, SEM 0.1-0.5 cm). Measures of Q-angle were also reliable and precise (ICC ≥0.85, SEM 0.2-0.4°). Findings from this investigation demonstrate that lower-body dimensions may be reliably and precisely measured through simple practical tests, when surface anatomic landmarks and standardized procedures are used. Although intertester reliability remains to be established, meticulous adherence to specific measurement protocols is likely to yield viable output for lower-body dimensions when more sophisticated methods are unavailable or inappropriate.

Extracellular signal-regulated protein kinase 1/2 (ERK1/2) moderates skeletal muscle growth; however, chronic responses of this protein to unique resistance exercise (RE) paradigms are yet to be explored. The purpose of this investigation was to describe the long-term response of ERK1/2 following circuit weight training (CWT), recreationally weight training (WT), powerlifting (PL) and weightlifting (WL). Independent t-tests were used to determine differences in trained groups compared to sedentary controls. Total ERK1/2 content was lower in PL and WL compared to their controls (p ≤ 0.05). Specific trained groups displayed large (WL: pERK/total-ERK; d = 1.25) and moderate (CWT: total ERK1/2; d = 0.54) effect sizes for altered kinase expression compared to controls. The results indicate ERK1/2 expression is down-regulated after chronic RE in well-trained weightlifters and powerlifters. Lower expression of this protein may be a method in which anabolism is tightly regulated after many years of high-intensity RE.

The purpose of this investigation was to examine the effects of footwear on kinetics and lower extremity electromyographic (EMG) activity during the vertical jump (VJ) and standing long jump. Fifteen men performed the 2 jump types in 3 footwear conditions: barefoot, minimal shoes, and cross-training shoes. Jump displacement and kinetic data were collected, along with EMG activity of the biceps femoris, medial gastrocnemius, peroneus longus, semitendinosus/semimembranosus, soleus (SOL), tibialis anterior, vastus lateralis, and vastus medialis. Subjective footwear performance and comfort were also assessed with a custom survey. No differences were found in jump displacement, peak ground reaction forces (GRF), countermovement and propulsive phase durations, vertical impulse, peak countermovement, or average propulsive EMG activity. Significant differences in peak propulsive root mean square EMG were found between barefoot and minimal shoes (p = 0.030) and minimal shoes and shod (p = 0.031) conditions for the SOL during the VJ, and for average countermovement EMG of the semitendinosus/semimembranosus during the VJ between barefoot and shod (p = 0.039). Moderate-to-large effect sizes (>0.59) were found between conditions for horizontal GRF, propulsive phase duration, average EMG amplitude, and duration of EMG activity during the countermovement. Participants reported higher comfort ratings when shod compared with barefoot and minimal shoes for both jumps. Participants also perceived better performance when shod compared with barefoot and minimal shoes for the VJ only. No acute differences in displacement were observed between barefoot, minimal shoes, and cross-trainer shoes during vertical and horizontal jumps. Some differences in muscle activation and timing seem to be present, and thus, training effects between footwear conditions should be examined. Footwear familiarization may prove beneficial, as acute increases in comfort seem unrelated to performance improvements.

Muscular activity, vertical displacement and ground reaction forces of back squats (BS), rear-leg elevated split squats (RLESS) and split squats (SS) were examined. Nine resistance-trained men reported for two sessions. The first session consisted of the consent process, practice, and BS 1-repetition maximum testing. In the second session, participants performed the three exercises while EMG, displacment and ground reaction force data (one leg on plate) were collected. EMG data were collected from the gluteus maximus (GMX), biceps femoris (BF), semitendinosus (ST), rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM), tibialis anterior (TA), and medial gastrocnemius (MGas) of the left leg (non-dominant, front leg for unilateral squats). Load for BS was 85% one repetition maximum, and RLESS and SS were performed at 50% of BS load. Repeated measures ANOVA was used to compare all variables for the three exercises, with Bonferroni adjustments for post hoc multiple comparisons, in addition to calculation of standardized mean differences (ES). Muscle activity was similar between exercises except for biceps femoris, which was significantly higher during RLESS than SS during both concentric and eccentric phases (ES = 2.11; p=0.012 and ES= 2.19; p=0.008), and significantly higher during BS than the SS during the concentric phase (ES = 1.78; p=0.029). Vertical displacement was similar between all exercises. Peak vertical force was similar between BS and RLESS and significantly greater during RLESS than SS (ES = 3.03; p=0.001). These findings may be helpful in designing resistance training programs by using RLESS if greater biceps femoris activity is desired.

The dorsal muscles of the lower torso and extremities have often been denoted the "posterior chain." These muscles are used to support the thoracic and lumbar spine and peripheral joints, including the hip, knee, and ankle on the dorsal aspect of the body. This study investigated the relative muscle activity of the hamstring group and selected surrounding musculature during the leg curl, good morning, glute-ham raise, and Romanian deadlift (RDL). Twelve healthy, weight-trained men performed duplicate trials of single repetitions at 85% 1-repetition maximum for each lift in random order, during which surface electromyography and joint angle data were obtained. Repeated measures analysis of variance across the 4 exercises was performed to compare the activity from the erector spinae (ES), gluteus medius (GMed), semitendinosus (ST), biceps femoris (BF), and medial gastrocnemius (MGas). Significant differences (p ≤ 0.05) were noted in eccentric muscle activity between exercise for the MGas (p < 0.027), ST (p < 0.001), BF (p < 0.001), and ES (p = 0.032), and in concentric muscle activity, for the ES (p < 0.001), BF (p = 0.010), ST (p = 0.009), MGas (p < 0.001), and the GMed (p = 0.018). Bonferroni post hoc analysis revealed significant pairwise differences during eccentric actions for the BF, ST, and MGas. Post hoc analysis also revealed significant pairwise differences during concentric actions for the ES, BF, ST, MGas, and GMed. Each of these showed effect sizes that are large or greater. The main findings of this investigation are that the ST is substantially more active than the BF among all exercises, and hamstring activity was maximized in the RDL and glute-ham raise. Therefore, athletes and coaches who seek to maximize the involvement of the hamstring musculature should consider focusing on the glute-ham raise and RDL.