Antimicrobial stewardship program for gastrointestinal surgeries at a Vietnamese tertiary hospital.

Background: Antimicrobial Stewardship Programs (ASP) have been applied widely in high-resource countries to prevent surgical site infections (SSI). Evidence favoring ASP interventions (ASPi) in gastrointestinal surgeries from low and middle-income countries has been limited, especially in antimicrobial prophylaxis. We aimed to investigate this gap at a Vietnamese tertiary hospital. Methods: We conducted a retrospective cohort study on patients undergoing clean-contaminated surgeries in 2015 who received standard of care (SoC) or SoC + ASPi. Primary outcome was 30-day SSI incidence. Secondary outcomes included length of stay (LoS) after surgery (days), cost of antibiotics, and cost of treatment (USD). Results were controlled for multiplicity and reported with treatment effect and 95% confidence interval (95%CI). A predictive model was built and cross-validated to detect patients at high risk of SSI. Results: We included 395 patients for analysis (48.1% being female, mean age 49.4 years). Compared to patients receiving SoC, those with SoC + ASPi had a lower incidence of 30-day SSI (-8.8, 95%CI: -16.0 to -1.6, p = 0.042), shorter LoS after surgery (-1.1 days, 95%CI: -1.8 to -0.4, p = 0.004), and lower cost of antibiotics (-37.3 USD, 95%CI: -59.8 to -14.8, p = 0.012) and treatment (-191.1 USD, 95%CI: -348.4 to -33.8, p = 0.042). We estimated that by detecting patients at high risk of SSI with the predictive model and providing prophylactic measures, we could save 398120.7 USD per 1,000 cases of SSI. Conclusion: We found that ASPi were associated with a reduction in risks of SSI, hospital stays, and cost of antibiotics/treatment in a Vietnamese tertiary hospital.

Efficient full solar spectrum-driven photocatalytic hydrogen production on low bandgap TiO2/conjugated polymer nanostructures.

The development of photocatalysts that can utilize the entire solar spectrum is crucial to achieving efficient solar energy conversion. The utility of the benchmark photocatalyst, TiO2, is limited only to the UV region due to its large bandgap. Extending the light harvesting properties across the entire spectrum is paramount to enhancing solar photocatalytic performance. In this work, we developed low bandgap TiO2/conjugated polymer nanostructures which exhibit full spectrum activity for efficient H2 production. The highly mesoporous structure of the nanostructures together with the photosensitizing properties of the conjugated polymer enabled efficient solar light activity. The mesoporous TiO2 nanostructures calcined at 550 °C exhibited a defect-free anatase crystalline phase with traces of brookite and high surface area, resulting in the best performance in hydrogen production (5.34 mmol g-1 h-1) under sunlight simulation. This value is higher not only in comparison to other TiO2-based catalysts but also to other semiconductor materials reported in the literature. Thus, this work provides an effective strategy for the construction of full spectrum active nanostructured catalysts for enhanced solar photocatalytic hydrogen production.

Standing Pelvic Tilt Is Associated With Dynamic Pelvic Tilt During Running When Measured by 3-Dimensional Motion Capture.

Standing pelvic tilt (PT) is related to biomechanics linked with increased risk of injury such as dynamic knee valgus. However, there is limited evidence on how standing PT relates to dynamic PT and whether the palpation meter (PALM), a tool to measure standing PT, is valid against 3-dimensional (3D) motion analysis. The purposes of this study were to (1) determine the criterion validity of the PALM for measuring standing PT and (2) identify the relationship between standing PT and dynamic PT during running. Participants (n = 25; 10 males and 15 females) had their standing PT measured by the PALM and 3D motion analysis. Dynamic PT variables were defined at initial contact and toe off. No relationship between the 2 tools was found. Significant large positive relationships between standing PT and PT at initial contact (r = .751, N = 25, P < .001) and PT at toe off (r = .761, N = 25, P < .001) were found. Since no relationship was found between standing PT measured by the PALM and 3D motion analysis, the PALM is not a valid alternative to 3D motion analysis. Clinicians may be able to measure standing PT and gain valuable information on dynamic PT, allowing clinicians to quickly assess whether further biomechanical testing is needed.

Women's College Volleyball Players Exhibit Asymmetries During Double-Leg Jump Landing Tasks.

CONTEXT: Women's volleyball requires frequent and repetitive jumping that when performed with altered biomechanics, including kinematic or kinetic asymmetry, may place the athlete at high risk for injury. This study identified and analyzed lower-extremity biomechanical asymmetries in college women's volleyball players during standard and sport-specific double-leg landing tasks. DESIGN: Cross-sectional laboratory study. METHODS: Eighteen female college volleyball players were analyzed using standard 3D motion capture techniques during a drop vertical jump and an unanticipated lateral reactive jump task. Repeated-measures multivariate analysis of variance identified asymmetries in kinematic and kinetic variables of each task. RESULTS: Average symmetry indices ranged from 9.3% to 31.3% during the drop vertical jump and 11.9% to 25.6% during the reactive jump task. During the drop vertical jump, the dominant limb exhibited lower knee abduction moments (P = .03), ankle dorsiflexion moments (P = .02), ankle eversion moments (P = .003) and vertical ground reaction forces (P = .03), and greater ankle inversion moments (P = .001). Both kinematic (λ = 0.27, P = .03) and kinetic (λ = 0.12, P = .008) asymmetries were identified during the reactive jump task. The dominant limb exhibited greater peak knee flexion (P = .003) and ankle dorsiflexion (P = .02) angles, and greater ankle dorsiflexion (P = .005) and inversion (P = .03) moments than the nondominant limb. CONCLUSIONS: These asymmetries observed during double-leg landing tasks may predispose volleyball athletes to unilaterally higher ground reaction or muscle forces and ultimately a greater risk of injury during landing.

A Successful Case of Cardiac Arrest due to Acute Myocarditis with COVID-19: 120 Minutes on Manual Cardiopulmonary Resuscitation then Veno-Arterial Extracorporeal Membrane Oxygenation.

Acute myocarditis is one of the common complications of coronavirus disease 2019 (COVID-19) with a relatively high case fatality. Here reported is a fulminant case of a 42-year-old previously healthy woman with cardiogenic shock and refractory cardiac arrest due to COVID-19-induced myocarditis who received veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) after 120 minutes of cardiopulmonary resuscitation (CPR). This is the first adult case of cardiac arrest due to COVID-19-induced myocarditis supported by ECMO that fully recovered with normal neurological functions. The success of the treatment course with full recovery emphasized the potential role of ECMO in treating these patients.

External Match Load in Women's Collegiate Lacrosse.

ABSTRACT: Devine, NF, Hegedus, EJ, Nguyen, A-D, Ford, KR, and Taylor, JB. External match load in women's collegiate lacrosse. J Strength Cond Res 36(2): 503-507, 2022-Quantifying external loads during athletic activities, particularly game-level competition, can provide objective data for the management of athlete performance, late-stage rehabilitation, and return-to-play decisions after lower extremity injury; yet, no studies have quantified these data in collegiate women's lacrosse athletes. The purpose of this study was to report external load values for collegiate women's lacrosse players and identify positional differences in activity demands during game competition. Load data were collected on 18 collegiate women's lacrosse players using a wearable global positioning system unit during a 19-game season. Descriptive statistics of distance, speed, and frequency (sprints, high-intensity sprints, high-intensity accelerations, high-intensity decelerations) measures were computed. Linear mixed models were used to identify differences between positions and phases of the season (α = 0.05). On average, players travelled 4,733 ± 2,294 m per game (range, 1,259-7,811 m), of which 656 ± 446 m (range 60-1,633 m) occurred at high-intensity speeds and reached a maximum speed of 24.1 ± 2.6 km·h-1 (range, 19.2-27.7 km·h-1). In each game, subjects averaged 124 ± 68 sprints, 6.1 ± 4.1 high-intensity sprints, 51 ± 34 high-intensity accelerations, and 38 ± 25 high-intensity decelerations. Positional differences were identified for total (p = 0.04) and relative (p = 0.01) distance travelled at high-intensity speeds, and frequency of sprints (p = 0.01) and high-intensity decelerations (p = 0.03). During game competition, collegiate women's lacrosse demands significant external load, much of which occurs at high intensities. These data provide sport- and position-specific values for reference during late-stage rehabilitation and return-to-play testing, allowing clinicians to quantitatively progress load tolerance throughout rehabilitation and guide safe return to play.

Insights into the light-driven hydrogen evolution reaction of mesoporous graphitic carbon nitride decorated with Pt or Ru nanoparticles.

Ru or Pt nanoparticles have been prepared following the organometallic approach and deposited onto the surface of mesoporous graphitic carbon nitride (mpg-CN). Three different Ru-based samples have also been compared to investigate the effect of 4-phenylpyridine as a stabilizing agent. The photocatalytic performance towards the hydrogen evolution reaction (HER) has been tested showing that all hybrid systems clearly outperform the photocatalytic activity of bare mpg-CN. In particular, Pt-decorated mpg-CN yields the largest H2 production upon visible-light irradiation (870 µmol h-1 g-1, TOF = 14.1 h-1, TON = 339 after 24 h) when compared with the Ru-based samples (137-155 µmol h-1 g-1, TOFs between 2.3-2.7 h-1, TONs between 54-57 after 24 h). Long-term photochemical tests (up to 65 h irradiation) show also an improved stability of the Pt-based samples over the Ru counterpart. Photophysical experiments aimed at rationalizing the photocatalytic performance of the different hybrid systems elucidate that the enhanced activity of the Pt-decorated mpg-CN over the Ru-based analogues arises from improved electron transfer kinetics from mpg-CN to the metal nanoparticles.

The Effects of Gluteal Strength and Activation on the Relationship Between Femoral Alignment and Functional Valgus Collapse During a Single-Leg Landing.

CONTEXT: A bias toward femoral internal rotation is a potential precursor to functional valgus collapse. The gluteal muscles may play a critical role in mitigating these effects. OBJECTIVE: Determine the extent to which gluteal strength and activation mediate associations between femoral alignment measures and functional valgus collapse. DESIGN: Cross-sectional. SETTING: Research laboratory. PATIENTS OR OTHER PARTICIPANTS: Forty-five females (age = 20.1 [1.7] y; height = 165.2 [7.6] cm; weight = 68.6 [13.1] kg) and 45 males (age = 20.8 [2.0] y; height = 177.5 [8.7] cm; weight = 82.7 [16.5] kg), healthy for 6 months prior. INTERVENTION(S): Femoral alignment was measured prone. Hip-extension and abduction strength were obtained using a handheld dynamometer. Three-dimensional biomechanics and surface electromyography were obtained during single-leg forward landings. MAIN OUTCOME MEASURES: Forward stepwise multiple linear regressions determined the influence of femoral alignment on functional valgus collapse and the mediating effects of gluteus maximus and medius strength and activation. RESULTS: In females, less hip abduction strength predicted greater peak hip adduction angle (R2 change = .10; P = .02), and greater hip-extensor activation predicted greater peak knee internal rotation angle (R2 change = .14; P = .01). In males, lesser hip abduction strength predicted smaller peak knee abduction moment (R2 change = .11; P = .03), and the combination of lesser hip abduction peak torque and lesser gluteus medius activation predicted greater hip internal rotation angle (R2 change = .15; P = .04). No meaningful mediation effects were observed (υadj < .01). CONCLUSIONS: In females, after accounting for femoral alignment, less gluteal strength and higher muscle activation were marginally associated with valgus movement. In males, less gluteal strength was associated with a more varus posture. Gluteal strength did not mediate femoral alignment. Future research should determine the capability of females to use their strength efficiently.

Gender-Specific Risk Factor Profiles for Patellofemoral Pain.

OBJECTIVE: To determine the association between selected biomechanical variables and risk of patellofemoral pain (PFP) in males and females. DESIGN: Prospective cohort. SETTING: US Service Academies. PARTICIPANTS: Four thousand five hundred forty-three cadets (1727 females and 2816 males). ASSESSMENT OF RISK FACTORS: Three-dimensional biomechanics during a jump-landing task, lower-extremity strength, Q-angle, and navicular drop. MAIN OUTCOME MEASURES: Cadets were monitored for diagnosis of PFP during their enrollment in a service academy. Three-dimensional hip and knee kinematic data were determined at initial contact (IC) and at 50% of the stance phase of the jump-landing task. Logistic regression analyses were performed for each risk factor variable in males and females (P < 0.05). RESULTS: Less than 10 degrees of hip abduction at IC [odds ratio (OR) = 1.86, P = 0.03] and greater than 10 degrees of knee internal rotation at 50% of the stance phase (OR = 1.71, P = 0.02) increased the risk of PFP in females. Greater than 20 degrees of knee flexion at IC (OR = 0.47, P < 0.01) and between 0 and 5 degrees of hip external rotation at 50% of the stance phase (OR = 0.52, P = 0.04) decreased the risk of PFP in males. No other variables were associated with risk of developing PFP (P > 0.05). CONCLUSIONS: The results suggest males and females have differing kinematic risk factor profiles for the development of PFP. CLINICAL RELEVANCE: To most effectively reduce the risk of developing PFP, the risk factor variables specific to males (decreased knee flexion and increased hip external rotation) and females (decreased hip abduction and increased knee internal rotation) should be addressed in injury prevention programs.

EFFECTS OF SURFACE ON TRIPLE HOP DISTANCE AND KINEMATICS.

BACKGROUND: The single leg triple hop (SLTH) test is often utilized by rehabilitation practitioners as a functional performance measure in a variety of patient groups. Accuracy and consistency are important when measuring the patient progress and recovery. Administering the SLTH test on different surfaces, consistent with the patient's sport, may affect the hop distances and movement biomechanics. PURPOSE: The purpose of this study was to examine the effects of court and turf surfaces on the hop distance, limb symmetry index (LSI), and lower extremity kinematics of a SLTH test. METHODS: Recreationally active female participants (n=11, height 163.8 ± 7.1cm, mass 63.1 ± 7.1kg, age 18.9 ± 0.9yrs), without injury, volunteered to participate in the study. Three maximal effort SLTH test trials on two different surfaces (court, synthetic turf) were collected and analyzed using 3D motion analysis techniques. Outcome variables included SLTH test distances and LSI values and sagittal plane kinematics including trunk, hip, knee and ankle range of motion (ROM) during the last two landings of each SLTH test trial. The second landing involves an absorption phase and propulsion phase in contrast to the final landing which involves absorption and final balance on the single leg. Paired t-tests were used to determine differences between surfaces in hop distance and LSI values. Two-way repeated measures ANOVA were used to determine differences between surfaces in kinematic variables. RESULTS: The total SLTH test distance was not statistically different between the court (4.11 ± 0.47m) and turf (4.03 ± 0.42m, p=0.47) surfaces. LSI for the court surface was 100.8 ± 3.0% compared to 99.7 ± 3.0% for turf surface, which was not statistically different (p=0.30). Knee flexion ROM was significantly less (p=0.04) on the turf compared to the court surface during the second landing. Ankle flexion range of motion was also significantly less (p=0.03) during the second landing on turf compared to court. CONCLUSIONS: Type of surface influenced landing kinematics but not total SLTH test distance. When evaluating the quality of landings during a SLTH test, it may be warranted to observe each type of landing and the type of surface used during single leg tests. LEVEL OF EVIDENCE: 2.

Effects of maturation on knee biomechanics during cutting and landing in young female soccer players.

Young female soccer players are at high risk of anterior cruciate ligament injury due to the fast-paced nature of the sport and surplus of unplanned movements during play. Neuromuscular training programs that aim to reduce this injury by targeting the associated biomechanical movements are a potential solution. While previous studies have examined the lack of dynamic knee control during landing, there are few that outline the role that maturation can play during unanticipated cutting. Therefore, the purpose of this study was to determine if young female soccer players across multiple phases of maturation exhibited the before seen differences in knee control during a drop landing as well as an unanticipated cutting task. 139 female soccer players volunteered to participate in this study and were classified in three maturational groups based on percent adult stature: prepubertal (PRE), pubertal (PUB), and post-pubertal (POST). Each group performed a drop vertical jump (DVJ) and an unanticipated cutting task (CUT). Standard 3D motion capture techniques were used to determine peak knee flexion/abduction angles and moments during each task. Within tasks, POST exhibited significantly greater peak abduction angles and moments compared to PUB/PRE. While each maturational group exhibited greater peak knee abduction angles during the DVJ compared to the CUT, peak knee abduction moments during the CUT were greater compared to the DVJ. Participants within each maturational group exhibited greater knee flexion during the DVJ compared to the CUT, however there were no differences identified between groups. During both tasks, POST/PUB exhibited greater peak knee flexion moments compared to PRE, as well as POST compared to PUB. Overall, each group exhibited significantly greater peak knee flexion moments during the CUT compared to the DVJ. These observed differences indicate the need for neuromuscular training programs that target both jumping and cutting techniques to reduce ACL injuries.

Methods of Identifying Limb Dominance in Adolescent Female Basketball Players: Implications for Clinical and Biomechanical Research.

OBJECTIVE: To identify relationships between self-reported limb preferences and performance measures for determining limb dominance in adolescent female basketball players. DESIGN: Cross-sectional cohort study. PARTICIPANTS: Forty adolescent female basketball players. INDEPENDENT VARIABLES AND MAIN OUTCOME MEASURES: Participants provided self-reported preferred kicking and jumping limbs, then completed 3 trials of a single-limb countermovement hop (HOPVER) and unilateral triple hop for distance (HOPHOR) on each limb. Each test was used to independently define limb dominance by the limb that produced the largest maximum vertical height and horizontal distance, respectively. RESULTS: Chi-square tests for independence identified a significant relationship between self-reported preferred kicking and jumping legs (χ = 7.41, P = 0.006). However, no significant relationships were found when comparing self-reported preference to measures of performance during the HOPHOR (χ = 0.33, P = 0.57) or HOPVER (χ = 0.06, P = 0.80). In addition, the 2 performance measures did not consistently produce the same definition of limb dominance among individuals (χ = 1.52, P = 0.22). CONCLUSIONS: Self-selection of the dominant limb is unrelated to performance. Furthermore, limb dominance, as defined by vertical jump height, is unrelated to limb dominance defined by horizontal jump distance. The results of this study call into question the validity of consistently defining limb dominance by self-reported measures in adolescent female basketball players.

Hip biomechanics differ in responders and non-responders to an ACL injury prevention program.

PURPOSE: To investigate the differences in demographic, anthropometric, biomechanical, and/or performance variables between those that do (responders) and do not (non-responders) exhibit reductions in knee abduction moments after an anterior cruciate ligament injury prevention program (ACL-IPP). METHODS: Forty-three adolescent female athletes completed biomechanical (3D motion analysis of a drop vertical jump) and performance testing before and after randomization into a 6-week ACL-IPP. Participants were classified into responders and non-responders based on their level of reduction of knee abduction moment from pre- to post-test. RESULTS: Compared to non-responders, responders exhibited increased hip adduction excursion at baseline (p = 0.02) and trended towards attending more training sessions (p = 0.07) and participating in soccer and not basketball (p = 0.07). Responders also showed greater improvements in hip flexion angles (p = 0.02) and moments (p < 0.001), and knee abduction angles (p < 0.001) and excursions (p = 0.001). There were no significant differences in age or experience with prior injury prevention programs (n.s.). CONCLUSIONS: After an ACL-IPP, athletes that exhibit the greatest reduction in knee abduction moments exhibit greater hip adduction excursion at baseline and show corresponding improvements in hip flexion and knee abduction kinematics and hip flexion moments. These results can help clinicians prospectively identify individuals that may not respond to an ACL-IPP and target individualized training for those at risk of injury. LEVEL OF EVIDENCE: I. CLINICAL TRIAL REGISTRATION NUMBER: Clinicaltrials.gov NCT02530333.

Temporal kinematic differences throughout single and double-leg forward landings.

Screening methods for anterior cruciate ligament (ACL) injuries often involve double-leg landings, though the majority of ACL injuries occur during single-leg landings. Differences in kinematic temporal characteristics between single-leg and double-leg landings are poorly understood. The purpose of this study was to examine discrete and temporal kinematics associated with functional valgus collapse during single-leg and double-leg landings (LANDSL and LANDDL). Three-dimensional kinematics were obtained during the landing phases of LANDSL and LANDDL in ninety participants (45 females: 20.1 ± 1.7 yr, 165.2 ± 7.6 cm, 68.6 ± 13.1 kg; 45 males: 20.7 ± 2.0 yr, 177.7 ± 8.5 cm, 82.8 ± 16.3 kg). Peak joint angles and time series curves for frontal and transverse plane hip and knee kinematics were analyzed with an RMANOVA (discrete variables) and Statistical Parametric Mapping (SPM) paired t-tests (time series). LANDSL elicited greater knee abduction than LANDDL from 0 to 35% (0-73 ms) but greater knee adduction from 54 to 100% (112-207 ms). Peak knee abduction was 2.0° greater during LANDDL than during LANDSL (p < .001). LANDSL elicited greater hip adduction than LANDDL from 2 to 33% (4-69 ms) and greater hip abduction from 49 to 100% (102-207 ms). Peak hip adduction was 4.6° greater during LANDSL than during LANDDL (p < .001). LANDSL elicited less knee internal rotation from 0 to 3% and greater hip internal rotation from 52 to 75% of the landing phase. Peak transverse plane joint angles did not differ between tasks. During the time frame in which ACL injuries are thought to occur, LANDSL elicited frontal plane knee and hip movement consistent with risky biomechanics. Researchers and clinicians should be cognizant of how a chosen screening task alters observed kinematic effects.

MODIFYING MIDSOLE STIFFNESS of BASKETBALL FOOTWEAR AFFECTS FOOT and ANKLE BIOMECHANICS.

BACKGROUND: There is a growing incidence of foot injuries in basketball, which may be from the sport's repetitive, forceful multi-directional demands. Modifying midsole stiffness of the basketball shoe has been reported to alter ankle motion and plantar forces to reduce the risk of injury; however, the effects on anatomical, in-shoe foot (metatarsal), motion is not well understood. PURPOSE: The purpose of this study was to identify differences in foot and ankle biomechanics between basketball shoes with differing midsole stiffness values during single-leg jump landings. It was hypothesized that a stiffer midsole would elicit lower 1st metatarsophalangeal joint (MTPJ) dorsiflexion angles, higher ankle dorsiflexion angles, and higher plantar forces and relative loading in the distal foot. STUDY DESIGN: Experimental cross-sectional study. METHODS: Twenty high school and collegiate-aged basketball players performed a single-leg side drop jump and a single-leg cross drop jump in a pair of standard basketball shoes and a pair of shoes modified with a fiberglass plate to increase midsole stiffness. Three-dimensional motion analysis and flexible insoles quantified foot and ankle kinematics and plantar force distribution, respectively. Separate 2 (footwear) × 2 (task) repeated measures ANOVA models were used to analyze differences in 1) ankle kinematics, 2) 1st metatarsophalangeal kinematics, 3) maximal regional plantar forces, and 4) relative load. RESULTS: The stiffer shoe elicited decreased peak ankle plantarflexion (mean difference = 5.8 °, p = 0.01) and eversion (mean difference = 6.6 °, p = 0.03) and increased peak ankle dorsiflexion angles (mean difference = 5.0 °, p = 0.008) but no differences were observed in 1st MTPJ motion (p > 0.05). The stiffer shoe also resulted in lower peak plantar forces (mean difference = 24.2N, p = 0.004) and relative load (mean difference = 1.9%, p = 0.001) under the lesser toes. CONCLUSIONS: Altering the midsole stiffness in basketball shoes did not reduce motion at the MTPJ, indicating that added stiffness may reduce shoe motion, but does not reduce in-shoe anatomical motion. Instead, a stiffer midsole elicits other changes, including additional ankle joint motion and a reduction in plantar forces under the lesser toes. Collectively, this indicates that clinicians need to account for unintended compensations that can occur throughout the kinetic chain when altering a shoe property to alleviate a musculoskeletal injury. LEVEL OF EVIDENCE: 2b.

Passive Hip Range-of-Motion Values Across Sex and Sport.

CONTEXT: Greater passive hip range of motion (ROM) has been associated with greater dynamic knee valgus and thus the potential for increased risk of anterior cruciate ligament injuries. Normative data for passive hip ROM by sex are lacking. OBJECTIVE: To establish and compare passive hip ROM values by sex and sport and to quantify side-to-side differences in internal-rotation ROM (ROMIR), external-rotation ROM (ROMER), and total ROM (ROMTOT). DESIGN: Cross-sectional study. SETTING: Station-based, preparticipation screening. PATIENTS OR OTHER PARTICIPANTS: A total of 339 National Collegiate Athletic Association Division I athletes, consisting of 168 women (age = 19.2 ± 1.2 years, height = 169.0 ± 7.2 cm, mass = 65.3 ± 10.2 kg) and 171 men (age = 19.4 ± 1.3 years, height = 200.0 ± 8.6 cm, mass = 78.4 ± 12.0 kg) in 6 sports screened over 3 years: soccer (58 women, 67 men), tennis (20 women, 22 men), basketball (28 women, 22 men), softball or baseball (38 women, 31 men), cross-country (18 women, 19 men), and golf (6 women, 10 men). MAIN OUTCOME MEASURE(S): Passive hip ROM was measured with the athlete lying prone with the hip abducted to 20° to 30° and knee flexed to 90°. The leg was passively internally and externally rotated until the point of sacral movement. Three measures were averaged for each direction and leg and used for analysis. We compared ROMIR, ROMER, ROMTOT (ROMTOT = ROMIR + ROMER), and relative ROM (ROMREL = ROMIR - ROMER) between sexes and among sports using separate 2 × 6 repeated-measures analyses of variance. RESULTS: Women had greater ROMIR (38.1° ± 8.2° versus 28.6° ± 8.4°; F1,327 = 91.74, P < .001), ROMTOT (72.1° ± 10.6° versus 64.4° ± 10.1°; F1,327 = 33.47, P < .001), and ROMREL (1.5° ± 16.0° versus -7.6° ± 16.5°; F1,327 = 37.05, P < .001) than men but similar ROMER (34.0° ± 12.2° versus 35.8° ± 11.5°; F1,327 = 1.65, P = .20) to men. Cross-country athletes exhibited greater ROMIR (37.0° ± 9.3° versus 30.9° ± 9.4° to 33.3° ± 9.5°; P = .001) and ROMREL (5.9° ± 18.3° versus -9.6° ± 16.9° to -2.7° ± 17.3°; P = .001) and less ROMER (25.7° ± 7.5° versus 35.0° ± 13.0° to 40.2° ± 12.0°; P < .001) than basketball, soccer, softball or baseball, and tennis athletes. They also displayed less ROMTOT (62.7° ± 8.1° versus 70.0° ± 9.1° to 72.9° ± 11.9°; P < .001) than basketball, softball or baseball, and tennis athletes. CONCLUSIONS: Women had greater ROMIR than men, resulting in greater ROMTOT and ROMREL. Researchers should examine the extent to which this greater bias toward ROMIR may explain women's greater tendency for dynamic knee valgus. With the exception of cross-country, ROM values were similar across sports. The clinical implications of these aberrant cross-country values require further study.

Preferred Hip Strategy During Landing Reduces Knee Abduction Moment in Collegiate Female Soccer Players.

CONTEXT: Hip-focused interventions are aimed to decrease frontal plane knee loading related to anterior cruciate ligament injuries. Whether a preferred hip landing strategy decreases frontal plane knee loading is unknown. OBJECTIVE: To determine if a preferred hip landing strategy during a drop vertical jump (DVJ) is utilized during a single-leg landing (SLL) task and whether differences in frontal plane knee loading are consistent between a DVJ and an SLL task. DESIGN: Descriptive laboratory study. SETTING: Research laboratory. PARTICIPANTS: Twenty-three collegiate, female soccer players. MAIN OUTCOME MEASURES: Participants were dichotomized into a hip (HIP; n = 9) or knee/ankle (KA; n = 14) strategy group based on the percentage distribution of each lower extremity joint relative to the summated moment (% distribution) during the DVJ. Separate 1-way analysis of variances examined the differences in joint-specific % distribution and external knee abduction moment between the HIP and KA groups. RESULTS: The HIP group had significantly greater % distribution of hip moment and less % distribution of knee moment compared with the KA group during the DVJ and SLL. External knee abduction moment was also significantly less in the HIP group compared with the KA group during the DVJ. CONCLUSIONS: Female soccer athletes who land with a preferred hip strategy during a DVJ also land with a preferred hip strategy during an SLL. The preferred hip strategy also resulted in less external knee abduction moments during the DVJ. CLINICAL RELEVANCE: Targeting the neuromuscular control of the hip extensor may be useful in reducing risk of noncontact anterior cruciate ligament injuries.

Female Athletes With Varying Levels of Vertical Stiffness Display Kinematic and Kinetic Differences During Single-Leg Hopping.

Vertical stiffness may contribute to lower-extremity injury risk; however, it is unknown whether athletes with different stiffness levels display differences in biomechanics. This study compared differences in biomechanics between female athletes (n = 99) with varying stiffness levels during a repetitive, single-leg, vertical hopping task. Vertical stiffness was calculated as the ratio of peak vertical ground-reaction force to maximum center-of-mass displacement. Tertiles were established using stiffness values, and separate 1-way ANOVAs were used to evaluate between-group differences. Stance times decreased, and flight times, ground-reaction force, and stiffness increased, from the low- to high-stiffness group (P < .050). The high-stiffness group displayed: (1) greater lateral trunk flexion (P = .009) and lesser hip adduction (P = .022) at initial ground contact compared to the low- and moderate-stiffness groups, respectively; (2) lesser peak hip adduction compared to the low-stiffness group (P = .040); (3) lesser lateral trunk-flexion (P = .046) and knee-flexion (P = .010) excursion compared to the moderate- and low-stiffness groups, respectively; and (4) greater peak hip-flexion (P = .001), ankle-dorsiflexion (P = .002), and ankle-eversion (P = .038) moments compared to the low-stiffness group. A wide range of variability in stiffness exists within a relatively homogenous population. Athletes with varying stiffness levels display biomechanical differences that may help identify the potential mechanism(s) by which stiffness contributes to injury risk.

Effects of turf and cleat footwear on plantar load distributions in adolescent American football players during resisted pushing.

Metatarsal and midfoot injuries are common in American football. Footwear design may influence injury rates by altering plantar foot loading patterns in these regions. The purpose of this study was to determine the effect of cleat design on in-shoe plantar foot loading during a football-specific, resisted pushing task. Twenty competitive football players (age 14.7 ± 1.8 years, height 1.72 ± 0.10 m, and mass 71.8 ± 26.9 kg) completed three trials of pushing a weighted sled at maximal effort in a standard shoe (CLEAT) and artificial turf-specific shoe (TURF), with flexible in-shoe force measuring insoles. Repeated measures ANOVAs identified mean differences in maximum force and relative load under all regions of the foot. Results showed higher forces in the CLEAT under the medial (p < 0.001) and lateral (p = 0.004) midfoot, central (p = 0.007) and lateral (p < 0.001) forefoot, and lesser toes (p = 0.01), but lower forces in the hallux (p = 0.02) compared to the TURF shoe. Additionally, relative loading was higher in the CLEAT under the medial (p < 0.001) and lateral (p = 0.002) midfoot and lateral (p < 0.001) forefoot, but lower in the medial forefoot (p = 0.006) and hallux (p < 0.001) compared to the TURF shoe. The two shoes elicited distinct plantar loading profiles and may influence shoe selection decisions during injury prevention or rehabilitation practices.

Reliability of analysis of the bone mineral density of the second and fifth metatarsals using dual-energy x-ray absorptiometry (DXA).

BACKGROUND: Metatarsal fractures, especially of the fifth metatarsal, are common injuries of the foot in a young athletic population, but the risk factors for this injury are not well understood. Dual-energy x-ray absorptiometry (DXA) provides reliable measures of regional bone mineral density to predict fracture risk in the hip and lumbar spine. Recently, sub-regional metatarsal reliability was established in fresh cadaveric specimens and associated with ultimate fracture force. The purpose of this study was to assess the reliability of DXA bone mineral density measurements of sub-regions of the second and fifth metatarsals in a young, active population. METHODS: Thirty two recreationally active individuals participated in the study, and the bone density of the second (2MT) and fifth (5MT) metatarsals of each subject was measured using a Hologic QDR x-ray bone densitometer. Scans were analyzed separately by two raters, and regional bone mineral density, bone mineral content, and area measurements were calculated for the proximal, shaft, and distal regions of the bone. Intra-rater, inter-rater, and scan-rescan reliability were then determined for each region. RESULTS: Proximal and shaft bone mineral density measurements of the second and fifth metatarsal were reliable. ICC's were variable across regions and metatarsals, with the distal region being the poorest. CONCLUSIONS: Bone mineral density measurements of the metatarsals may be a better indicator of fracture risk of the metatarsals than whole body measurements. A reliable method for measuring the regional bone mineral densities of the metatarsals was found. However, inter-rater reliability and scan-rescan reliability for the distal regions were poor. Future research should examine the relationship between DXA bone mineral density measurements and fracture risk at the metatarsals.