Experiences of Interpersonal Violence in Sport and Perceived Coaching Style Among College Athletes.

Importance: Concern about interpersonal violence (IV) in sport is increasing, yet its implications remain poorly understood, particularly among currently competing college athletes. Objective: To document the self-reported prevalence of IV in college sports; identify associated risk factors; examine potential consequences associated with athletes' psychosocial well-being, emotional connection to their sport, and willingness to seek help; and explore the associations between IV reporting and perceived variations in coaching styles. Design, Setting, and Participants: This survey study analyzes results of the 2021 to 2022 National Collegiate Athletic Association (NCAA) myPlaybook survey, which was administered from July to December 2021 to 123 colleges and universities across the US. Participants were NCAA athletes aged 18 to 25 years who were current players on an NCAA-sanctioned team. Exposures: Self-reported demographic characteristics (eg, athlete gender identity and sexual orientation) and perceived differences in supportive vs abusive coaching styles (eg, athlete autonomy, team culture, and extent of abusive supervision). Main Outcomes and Measures: The primary outcome was self-reported experiences of IV in sport during the college sports career of currently competing college athletes. Types of IV considered were physical abuse, financial abuse, sexual abuse, psychological or emotional abuse, and neglect or abandonment. Outcomes potentially affected by IV were assessed with 4 questionnaires. Results: A total of 4119 athletes (mean [SD] age, 19.3 [1.5] years; 2302 males [55.9%]) completed the survey (response rate, 21.2%). One in 10 athletes (404 of 4119 [9.8%]) reported experiencing at least 1 type of IV during their college sports career, of whom two-thirds (267 [6.5%]) experienced IV within the past 6 weeks. On multivariable analysis, female gender identity (odds ratio [OR], 2.14; 95% CI, 1.46-3.13), nonheterosexual sexual orientation (OR, 1.56; 95% CI, 1.01-2.42), increasing age beyond 18 years (OR, 1.13; 95% CI, 1.01-1.30), increasing year of NCAA eligibility beyond the first year (OR, 1.19; 95% CI, 1.02-1.39), and participation in select sports (eg, volleyball: OR, 2.77 [95% CI, 1.34-5.72]; ice hockey: OR, 2.86 [95% CI, 1.17-6.95]) were independently associated with IV. When exposed to IV, college athletes reported experiencing consistently worse psychosocial outcomes, including increased burnout (mean difference on a 5-point Likert scale, 0.75; 95% CI, 0.63-0.86; P < .001) and an expressed desire to consider quitting their sport (mean difference, 0.81; 95% CI, 0.70-0.92; P < .001). They were not, however, less willing to seek help. Differences in coaching style were associated with differences in IV reporting. In risk-adjusted linear regression models, having a more supportive coach was associated with a 7.4 (95% CI, 6.4-8.4) absolute percentage point decrease in athletes' probability of reporting experiencing IV. In contrast, having a more abusive coach was associated with up to a 15.4 (95% CI, 13.8-17.1) absolute percentage point increase in athletes' probability of reporting experiencing IV. Conclusions and Relevance: Results of this survey study suggest that IV is associated with marked changes in the psychosocial health and emotional well-being of college athletes, particularly those who identify as female and with nonheterosexual sexual orientations. Variations in coaching style have the potential to alter these associations. Ongoing efforts are needed to leverage the unique position that coaches hold to help reduce IV and create safe places where all college athletes can thrive.

Female aging: when translational models don't translate.

For many pathologies associated with aging, female patients present with higher morbidity and more frequent adverse events from treatments compared to male patients. While preclinical models are the foundation of our mechanistic understanding of age-related diseases, the most common models fail to recapitulate archetypical female aging trajectories. For example, while over 70% of the top age-related diseases are influenced by the systemic effects of reproductive senescence, we found that preclinical studies that include menopausal phenotypes modeling those seen in humans make up <1% of published aging biology research. The long-term impacts of pregnancy, birthing and breastfeeding are also typically omitted from preclinical work. In this Perspective, we summarize limitations in the most commonly used aging models, and we provide recommendations for better incorporating menopause, pregnancy and other considerations of sex in vivo and in vitro. Lastly, we outline action items for aging biology researchers, journals, funding agencies and animal providers to address this gap.

Quantitative and qualitative disparities exist between baseball and softball peer-reviewed pitching-related literature: a systematic review from 1990 to 2020.

Background: Baseball and softball are popular sports with similar rates of injury, especially among pitchers. However, parity between the two sports is lacking, as baseball receives greater research attention than softball. The purpose of this study was to describe the discrepancy between baseball and softball in terms of quantity and quality of research. We hypothesized baseball literature would outnumber softball literature, be published in higher-impact journals, and be of higher quality. Methods: A systematic review was performed to identify original research articles related to baseball and softball from 1990 to 2020. Articles pertaining to pitching were identified via literature searches of PubMed, the Physiotherapy Evidence Database, the Cumulative Index to Nursing and Allied Health Literature, and the Cochrane Central Register of Controlled Trials and further screened by two independent reviewers. Age group studied, journal impact factor, type of research, and level of evidence were compared between pitching-related baseball and softball articles. Injury-related studies were also subanalyzed, and a meta-analysis was performed to assess rates of shoulder and elbow injuries between baseball and softball pitchers. Results: There were 813 baseball publications and 158 softball publications that met our inclusion criteria. More baseball articles were published per year than softball (5:1, P < .001). Baseball had 368 articles related to pitching, while softball had significantly fewer at 49, and there were more baseball pitching articles published per year than softball pitching articles (7.5:1, P < .001). Pitching-related baseball articles were published in journals with a higher mean impact factor than softball pitching articles (3.1 vs. 2.0, P = .049). There was no difference in methodological index for non-randomized studies criteria for rigorous reporting (P = .678), and among all groups, most articles were level III evidence. Baseball pitching articles included more clinical articles than softball pitching articles (63% vs. 43%, P = .004). Despite the fact that softball pitchers have an odds ratio of shoulder and elbow injury slightly higher than baseball (4.02 vs. 3.60), injury-related studies focused on baseball outnumbered softball studies 7 to 1. Conclusion: Softball is under-represented in the literature when compared to baseball with over 5 times fewer peer-reviewed research articles, despite having slightly higher shoulder and elbow injury rates than baseball. Pitching-related softball articles are nearly 8 times less frequent compared to baseball pitching articles and published in journals with a lower impact factor. Further research directed at softball is important to provide evidence-based injury prevention, practice guidelines, and treatment decisions.

Dynamical modeling reveals RNA decay mediates the effect of matrix stiffness on aged muscle stem cell fate.

Loss of muscle stem cell (MuSC) self-renewal with aging reflects a combination of influences from the intracellular (e.g., post-transcriptional modifications) and extracellular (e.g., matrix stiffness) environment. Whereas conventional single cell analyses have revealed valuable insights into factors contributing to impaired self-renewal with age, most are limited by static measurements that fail to capture nonlinear dynamics. Using bioengineered matrices mimicking the stiffness of young and old muscle, we showed that while young MuSCs were unaffected by aged matrices, old MuSCs were phenotypically rejuvenated by young matrices. Dynamical modeling of RNA velocity vector fields in silico revealed that soft matrices promoted a self-renewing state in old MuSCs by attenuating RNA decay. Vector field perturbations demonstrated that the effects of matrix stiffness on MuSC self-renewal could be circumvented by fine-tuning the expression of the RNA decay machinery. These results demonstrate that post-transcriptional dynamics dictate the negative effect of aged matrices on MuSC self-renewal.

Age-related matrix stiffening epigenetically regulates α-Klotho expression and compromises chondrocyte integrity.

Extracellular matrix stiffening is a quintessential feature of cartilage aging, a leading cause of knee osteoarthritis. Yet, the downstream molecular and cellular consequences of age-related biophysical alterations are poorly understood. Here, we show that epigenetic regulation of α-Klotho represents a novel mechanosensitive mechanism by which the aged extracellular matrix influences chondrocyte physiology. Using mass spectrometry proteomics followed by a series of genetic and pharmacological manipulations, we discovered that increased matrix stiffness drove Klotho promoter methylation, downregulated Klotho gene expression, and accelerated chondrocyte senescence in vitro. In contrast, exposing aged chondrocytes to a soft matrix restored a more youthful phenotype in vitro and enhanced cartilage integrity in vivo. Our findings demonstrate that age-related alterations in extracellular matrix biophysical properties initiate pathogenic mechanotransductive signaling that promotes Klotho promoter methylation and compromises cellular health. These findings are likely to have broad implications even beyond cartilage for the field of aging research.

A Retrospective Analysis of Clinical Utilization Between Patients Who Used Telemedicine and Office Visits in Outpatient Physical Medicine and Rehabilitation Clinics During the COVID-19 Pandemic.

OBJECTIVE: To describe the demographic characteristics of patients who used telemedicine and office visits in physical medicine and rehabilitation during the COVID-19 pandemic and to quantify differences in clinical utilization between groups. Clinical utilization was defined as emergency department, urgent care, and hospital visits. DESIGN: This was a retrospective cohort study of 1096 patients who used telemedicine and 1171 patients who used office visits from April to June 2020 in the outpatient physical medicine and rehabilitation clinics at University of Pittsburgh Medical Center for musculoskeletal-related complaints. RESULTS: The telemedicine groups contained proportionally more people of color and higher comorbidities than the office visit groups. Patients who were seen in the telemedicine groups were more likely to be prescribed opioids than the office visit group. There were no differences in clinical utilizations between the telemedicine and office visit groups. CONCLUSIONS: The higher use of telemedicine in patients of color suggests a need for studying long-term outcomes to evaluate differences in care standards. There is an urgent need to understand how telemedicine affects opioid prescribing practices. Lastly, future studies are needed to understand why there were no differences in clinical utilization between the telemedicine and office visit groups.

The Impact of COVID-19 on Physician-Scientist Trainees and Faculty in the United States: A National Survey.

PURPOSE: Physician-scientists have long been considered an endangered species, and their extended training pathway is vulnerable to disruptions. This study investigated the effects of COVID-19-related challenges on the personal lives, career activities, stress levels, and research productivity of physician-scientist trainees and faculty. METHOD: The authors surveyed medical students (MS), graduate students (GS), residents/fellows (R/F), and faculty (F) using a tool distributed to 120 U.S. institutions with MD-PhD programs in April-June 2020. Chi-square and Fisher's exact tests were used to compare differences between groups. Machine learning was employed to select variables for multivariate logistic regression analyses aimed at identifying factors associated with stress and impaired productivity. RESULTS: The analyses included 1,929 respondents (MS: n = 679, 35%; GS: n = 676, 35%; R/F: n = 274, 14%; F: n = 300, 16%). All cohorts reported high levels of social isolation, stress from effects of the pandemic, and negative impacts on productivity. R/F and F respondents were more likely than MS and GS respondents to report financial difficulties due to COVID-19. R/F and F respondents with a dual degree expressed more impaired productivity compared with those without a dual degree. Multivariate regression analyses identified impacted research/scholarly activities, financial difficulties, and social isolation as predictors of stress and impaired productivity for both MS and GS cohorts. For both R/F and F cohorts, impacted personal life and research productivity were associated with stress, while dual-degree status, impacted research/scholarly activities, and impacted personal life were predictors of impaired productivity. More female than male respondents reported increased demands at home. CONCLUSIONS: This national survey of physician-scientist trainees and faculty found a high incidence of stress and impaired productivity related to the COVID-19 pandemic. Understanding the challenges faced and their consequences may improve efforts to support the physician-scientist workforce in the postpandemic period.

Meta-analysis Integrated With Multi-omics Data Analysis to Elucidate Pathogenic Mechanisms of Age-Related Knee Osteoarthritis in Mice.

Increased mechanistic insight into the pathogenesis of knee osteoarthritis (KOA) is needed to develop efficacious disease-modifying treatments. Though age-related pathogenic mechanisms are most relevant to the majority of clinically presenting KOA, the bulk of our mechanistic understanding of KOA has been derived using surgically induced posttraumatic OA (PTOA) models. Here, we took an integrated approach of meta-analysis and multi-omics data analysis to elucidate pathogenic mechanisms of age-related KOA in mice. Protein-level data were integrated with transcriptomic profiling to reveal inflammation, autophagy, and cellular senescence as primary hallmarks of age-related KOA. Importantly, the molecular profiles of cartilage aging were unique from those observed following PTOA, with less than 3% overlap between the 2 models. At the nexus of the 3 aging hallmarks, advanced glycation end product (AGE)/receptor for AGE (RAGE) emerged as the most statistically robust pathway associated with age-related KOA. This pathway was further supported by analysis of mass spectrometry data. Notably, the change in AGE-RAGE signaling over time was exclusively observed in male mice, suggesting sexual dimorphism in the pathogenesis of age-induced KOA in murine models. Collectively, these findings implicate dysregulation of AGE-RAGE signaling as a sex-dependent driver of age-related KOA.

Preliminary Evaluation of Dynamic Knee Valgus and Serum Relaxin Concentrations After ACL Reconstruction.

BACKGROUND: Athletes who have sustained a tear of the anterior cruciate ligament (ACL) are at a greater risk of re-tear and of developing other adverse outcomes, such as knee osteoarthritis, compared with uninjured athletes. Relaxin, a peptide hormone similar in structure to insulin, has been shown to interfere with the structural integrity of the ACL in female individuals. The purpose of the present study was to evaluate dynamic knee valgus and the serum relaxin concentration (SRC) in athletes who had previously sustained a torn ACL and in those who had not. METHODS: The study included 22 female athletes, divided into 2 groups: those who had previously sustained a torn ACL (4 participants; torn ACL in the dominant leg in all cases) and those who had not (18 participants). Kinematic data were collected at 100 Hz. To assess dynamic knee valgus, participants performed a single-leg squat, a single-leg crossover dropdown, and a drop vertical jump at 2 time points in the menstrual cycle of the patient, pre-ovulatory and mid-luteal. SRC was determined with use of the Human Relaxin-2 Immunoassay using a blood sample obtained during the mid-luteal phase of the menstrual cycle. RESULTS: Independent samples t tests were utilized to compare the differences in dynamic knee valgus and SRC between groups. For the single-leg squat, participants with a prior torn ACL were found to have significantly higher dynamic knee valgus at the mid-luteal phase but not at the pre-ovulatory phase. For the drop vertical jump and single-leg crossover dropdown, participants with a prior torn ACL were found to have significantly higher dynamic knee valgus at both the pre-ovulatory and mid-luteal phases. SRC was also significantly higher among participants with a prior torn ACL. CONCLUSIONS: Participants who had previously sustained a torn ACL had higher SRC and more dynamic knee valgus compared with those who had not. Further investigation of the effects of hormones as a risk factor for reinjury in participants with a prior ACL tear may be worthwhile. In addition, it may be worth monitoring hormonal and biomechanical properties in athletes during the long-term recovery from ACL reconstruction. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

The Relationship between Serum Relaxin Concentrations and Knee Valgus.

Female athletes are at an elevated risk for tearing their anterior cruciate ligament, compared to their male counterparts. Though injury screening clinical tests and neuromuscular training programs have been widely implemented, injury rates remain high among female athletes. The purpose of this study was to examine the relationship between serum relaxin concentrations and knee valgus during three clinical tests (single leg squat, drop vertical jump, and single leg crossover dropdown). Twenty-two female athletes volunteered. Participants were scheduled for collection during the mid-luteal phase, when serum relaxin concentrations are known to be measurable. Blood samples were collected, and serum relaxin concentrations were quantified. Kinematic data were collected while participants performed the three clinical tests. Regression analyses revealed statistically significant relationships between serum relaxin concentrations and knee valgus throughout all tests. These findings suggest that serum relaxin concentrations and knee valgus are not independent of each other and more holistic approaches may be necessary to truly map out the risk for injury and ultimately reduce the rate of anterior cruciate ligament injuries. Thus, concluding that knee valgus, a highly utilized modifiable biomechanical risk factor, and relaxin, a hormone that has been associated with anterior cruciate ligament injury in female athletes, are related to each other.

Preliminary Evaluation of Knee Kinetics in Female Athletes on Hormonal Contraceptives.

Recently, an emphasis has been placed on understanding how ovarian sex hormones and hormonal contraceptives affect risk for anterior cruciate ligament (ACL) injury. The literature presents large discrepancies in whether or not hormonal contraceptives affect ACL injury risk; therefore, the purpose of this study was to evaluate whether vertical ground reaction force (GRF) and knee valgus force are different between athletes who do and do not use hormonal contraceptives. Twenty-two female athletes volunteered to participate and were divided into two groups based on their answers to a health history questionnaire: those who use hormonal contraceptives and those who do not. Participants performed a drop vertical jump (DVJ) and single leg crossover dropdown (SCD) at two different time points in their menstrual cycle (pre-ovulatory phase and mid-luteal phase). Kinetic data were collected at 1000 Hz. Independent samples t-tests revealed no significant differences between groups in vertical GRF and knee valgus force at both time points. Findings from this study suggest that hormonal contraceptives do not elicit detectable changes in vertical GRF and knee valgus force. Ultimately, this calls for further studies on the relationship between hormones and ACL injury risk and physicians to consider hormonal screening in addition to neuromuscular and biomechanical screening.

Functional differences in softball pitchers with and without upper extremity pain.

OBJECTIVES: Though pitchers often throw during multiple games in a day, there are currently no pitch count restrictions in softball. The accumulation of high pitch counts over time may contribute to the development of upper extremity pain. The purpose of our study was to examine functional characteristics of shoulder and hip range of motion (ROM), isometric strength (ISO), and ball speed in softball pitchers with and without upper extremity (UE) pain. DESIGN: Controlled laboratory design. METHODS: Fifty-three NCAA Division I softball pitchers (20.0±1.4 years; 173.3±8.3cm; 80.9±12.3kg) participated and were divided into two groups: pain-free (n=30) and pain in the UE (n=23). Bilateral shoulder and hip external rotation (ER) and internal rotation (IR) ROM and ISO were measured prior to pitching to a catcher located 13.1m (43ft) away. RESULTS: Independent samples t-tests revealed significantly greater throwing side (TS) hip ER ROM (p=0.012), TS hip IR ISO (p=0.038), glove side (GS) hip ER ISO (p=0.025), TS shoulder ER ISO (p=0.002), GS shoulder IR (p=0.006) and ER (p=0.004) ISO in the pain free group versus the UE pain group. CONCLUSIONS: Differences in shoulder and hip ROM and ISO exist between those who have upper extremity pain and those who do not. Therefore, findings suggest that both the upper and lower extremities should be considered when treating softball pitchers with UE pain.

RNA-Seq and protein mass spectrometry in microdissected kidney tubules reveal signaling processes initiating lithium-induced nephrogenic diabetes insipidus.

Lithium salts, used for treating bipolar disorder, frequently induce nephrogenic diabetes insipidus (NDI) thereby limiting therapeutic success. NDI is associated with loss of expression of the gene coding for the molecular water channel, aquaporin-2, in the renal collecting duct (CD). Here, we use systems biology methods in a well-established rat model of lithium-induced NDI to identify signaling pathways activated at the onset of polyuria. Using single-tubule RNA-Seq, full transcriptomes were determined in microdissected cortical collecting ducts (CCDs) of rats after 72 hours without or with initiation of lithium chloride administration. Transcriptome-wide changes in mRNA abundances were mapped to gene sets associated with curated canonical signaling pathways, showing evidence for activation of NF-κB signaling with induction of genes coding for multiple chemokines and most components of the Major Histocompatibility Complex Class I antigen-presenting complex. Administration of anti-inflammatory doses of dexamethasone to lithium chloride-treated rats countered the loss of aquaporin-2. RNA-Seq also confirmed prior evidence of a shift from quiescence into the cell cycle with arrest. Time course studies demonstrated an early (12 hour) increase in multiple immediate early response genes including several transcription factors. Protein mass spectrometry in microdissected CCDs provided corroborative evidence and identified decreased abundance of several anti-oxidant proteins. Thus, in the context of prior observations, our study can be best explained by a model in which lithium increases ERK activation leading to induction of NF-κB signaling and an inflammatory-like response that represses Aqp2 transcription.

Differences in trunk and upper extremity kinematics and segmental velocities during the offside forehand polo swing between male and female athletes.

Although polo is a well-known equestrian sport, it is fundamentally misunderstood. The purpose of this study was to examine trunk and upper extremity kinematics and segmental velocities during the offside forehand polo swing between male and female athletes. Ten female and 17 male professional polo athletes volunteered. An electromagnetic tracking system collected kinematic data at 100 Hz while participants performed three offside forehand polo swings from a stationary wooden horse. One-way ANOVAs revealed statistically significant differences (p<0.05) in all kinematic variables and segmental velocities. Specifically, males exhibited a greater mean difference (MD=23°) of trunk flexion at take away (TA) and top of backswing (TOB)(MD=29°) trunk lateral flexion at ball contact (BC)(MD=23°), trunk rotation at TA(MD=97°) and TOB(MD=118°), shoulder abduction at TOB(MD=64°), and shoulder elevation at TOB(MD=13°) and BC(MD=40°). Females displayed greater trunk rotation at BC(MD=91°), shoulder elevation at TA(MD=19°), and elbow flexion at TA(MD=90°). Additionally, females generated greater segmental velocities early in the swing, while the males generated velocity later. The movement patterns observed amongst the males suggest energy is being transferred more efficiently along the kinetic chain, thus more efficient swing mechanics, but further investigation into the role of the trunk and lumbopelvic-hip complex in reference to the polo swing is warranted.

The Role of Lumbopelvic-Hip Complex Stability in Softball Throwing Mechanics.

CONTEXT: Studies have found that a 20% reduction in energy generation from the lumbopelvic-hip complex during overhead throws leads to a 34% increase in load on the shoulder. OBJECTIVE: The purpose of this study was to assess the effects of lumbopelvic-hip complex stability, via the single leg squat assessment, on throwing mechanics of softball athletes. DESIGN: Prospective cohort study. SETTING: Laboratory setting. PARTICIPANTS: A total of 50 softball athletes (164.0 [104.0] cm, 65.6 [11.3] kg, 16.3 [3.8] y, 8.61 [3.62] y of experience) performed 3 overhead throws and a single leg squat on each leg. INTERVENTION: Four stability groups were derived: (1) stable on both legs (bilateral stability), (2) unstable on the throwing side leg (TS instability) and stable on the nonthrowing side leg, (3) unstable on the nonthrowing side leg (NTS instability) and stable on the throwing side leg, and (4) unstable on both legs (bilateral instability). All throws were analyzed across 4 throwing events: foot contact (FC), maximum external shoulder rotation (MER), ball release (BR), and maximum internal shoulder rotation (MIR). MAIN OUTCOME MEASURES: Mann-Whitney U tests revealed significant differences between the bilateral stability and the TS instability groups in trunk flexion at BR; the bilateral stability and the NTS instability groups in trunk flexion at BR, shoulder horizontal abduction at FC, shoulder rotation at FC, and pelvis flexion at MIR; the TS instability and the bilateral instability groups in trunk rotation at FC; and the NTS instability and the bilateral instability groups in trunk flexion at MER and shoulder rotation at FC. CONCLUSION: These findings demonstrate the different mechanisms in which energy can be lost through lumbopelvic-hip complex instability as evident in throwing mechanics. The findings from this study suggest that the current methods used for classification could act as a tool for coaches, physicians, and athletic trainers when assessing their athletes' injury susceptibility.

Upper Extremity Pain and Pitching Mechanics in National Collegiate Athletic Association (NCAA) Division I Softball.

The purpose of this study was to evaluate pitching mechanics between female softball pitchers with upper extremity pain and those without upper extremity pain. Specifically, the trunk, shoulder and elbow kinematics and shoulder kinetics during the change-up softball pitch were examined. Fifty-five collegiate softball pitchers participated, divided into those with upper extremity pain (20.0±1.3 yrs.; 174.4±6.9 cm; 82.9±12.4 kg; 11.1±2.6 yrs. of experience; n=23) and those who were pain-free (19.9±1.4 yrs.; 173.8±6.9 cm; 81.4±12.5 kg; 10.0±2.5 yrs. of experience; n=32). Pitching mechanics were obtained via the trakSTAR™ electromagnetic tracking system (Ascension Technologies, Inc., Burlington, VT, USA). Mann-Whitney U tests revealed significant differences in shoulder horizontal abduction at foot contact (p=0.014, U=153, Z=2.450) and trunk lateral flexion at ball release (p=0.012, U=150, Z=-2.515); and between shoulder distraction force at ball release (p=0.034, U=168, Z=-2.124). The pain group illustrated greater shoulder horizontal abduction at foot contact, less trunk lateral flexion towards the throwing side at ball release, and greater shoulder distraction at ball release than the pain-free group. The differences in trunk and shoulder kinematics, and shoulder kinetics between groups allows for insight into further studies examining injury pervasiveness in softball pitching.

BIOMECHANICAL INFLUENCES OF A POSTURAL COMPRESSION GARMENT ON SCAPULAR POSITIONING.

BACKGROUND: The scapula is a critical link utilized in the kinetic chain to achieve efficient overhead movement and transfer energy from the lower extremity to the upper extremity. Additionally, daily activities such as sitting at a computer or driving in a car may negatively influence an individual's ability to maintain proper body posture and therefore compromise those movements. To reduce these negative influences, posture garments have been designed to cue the individual in maintaining and improving posture and alignment, specifically targeting scapular positioning. PURPOSE: The purpose of this study was to compare scapular positioning between an IntelliSkin™ posture-cueing compression garment and a generic performance garment on scapular kinematics during static standing.Study Design: Case control. METHODS: Forty active females (1.68 ± 0.07 m; 67.29 ± 11.25 kg) stood in a natural standing position while wearing two different garments: IntelliSkin™ posture-cueing compression garment and a generic performance garment. Kinematic data were collected at 100 Hz using an electromagnetic tracking system (trakSTAR™, Ascension Technologies, Inc., Burlington, VT, USA) synced with The MotionMonitor® (Innovative Sports Training, Chicago, IL., USA). RESULTS: Repeated measures ANOVAs revealed a statistically significant Shirt by Side interaction for scapular protraction/retraction (F(1,39) = 52.91, p ≤ 0.05) and main-effect of Shirt for scapula anterior/posterior tilt (F(1,39) = 96.45, p ≤ 0.05). Individuals showed increased retraction and posterior tilt while wearing the IntelliSkin™ posture-cueing compression garment. CONCLUSION: The results of the current study indicate that the IntelliSkin™ posture-cueing compression garment improved scapular positioning during static standing posture. The IntelliSkin™ posture-cueing compression garment may provide clinicians an adjunct strategy to include with rehabilitative protocols. LEVEL OF EVIDENCE: Diagnosis, Level 3.

Flow resistance along the rat renal tubule.

The Reynolds number in the renal tubule is extremely low, consistent with laminar flow. Consequently, luminal flow can be described by the Hagen-Poiseuille laminar flow equation. This equation calculates the volumetric flow rate from the axial pressure gradient and flow resistance, which is dependent on the length and diameter of each renal tubule segment. Our goal was to calculate the pressure drop along each segment of the renal tubule and to determine the points of highest resistance. When the Hagen-Poiseuille equation was used for rat superficial nephrons based on known tubule flow rates, lengths, and diameters, it was found that the maximum pressure drop occurred in two segments: the thin descending limbs of Henle and the inner medullary collecting ducts. The high resistance in the thin descending limbs is due to their small diameters. The steep pressure drop observed in the inner medullary collecting ducts is due to the convergent structure of the tubules, which channels flow into fewer and fewer tubules toward the papillary tip. For short-looped nephrons, the calculated glomerular capsular pressure matched measured values, even with the high collecting duct flow rates seen in water diuresis, provided that tubule compliance was taken into account. In long-looped nephrons, the greater length of thin limb segments is likely compensated for by a larger luminal diameter. Simulation of the effect of proximal diuretics, namely acetazolamide or type 2 sodium-glucose transporter inhibitors, predicts a substantial back pressure in Bowman's capsule, which may contribute to observed decreases in glomerular filtration rate.

Acute Hip Abduction Fatigue on Lumbopelvic-Hip Complex Stability in Softball Players.

During an overhead throw, the gluteal muscle group stabilizes the lumbopelvic-hip complex (LPHC), leading to efficient energy transfer from the lower to upper extremity. It has been shown that LPHC instability can lead to throwing pathomechanics. The single leg squat has become a common assessment for LPHC stability, and could be used to determine the effects of fatigue on throwing athletes. The purpose of this study was to determine the effects of an acute abduction fatigue protocol on the LPHC of collegiate softball players via the single leg squat assessment of the leg ipsilateral to the throwing arm. Eighteen National Collegiate Athletic Association Division I softball players volunteered (20.5±1.9 years; 169.4±10.0 cm; 72.9±11.5 kg). Each participant performed a single leg squat on the leg ipsilateral to the throwing arm prior to and post side-lying hip abduction fatigue. LPHC and lower extremity kinematics were examined to determine potential effects of fatigue on LPHC stability. There were no significant main effects or interactions of LPHC or lower extremity kinematics during the single leg squat assessments across the fatigue protocol. Based on the current study, an acute bout of fatigue to the hip abductors does not affect LPHC stability in single leg squat execution.