Effects of Static and Dynamic Hamstring Stretching on Anaerobic Exercise Performance

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Comparative study of the effects of ceftizoxime, piperacillin, and piperacillin-tazobactam concentrations on antibacterial activity and selection of antibiotic-resistant mutants of Enterobacter cloacae and Bacteroides fragilis in vitro and in vivo in mixed-infection abscesses

The effects of ceftizoxime (CZX), piperacillin (PIP), and PIP-tazobactam (PT) concentrations on the antibacterial activity and selection of resistant mutants of Bacteroides fragilis and Enterobacter cloacae were investigated in vitro in a mixed-culture anaerobic time-kill study and in vivo in a mixed-infection abscess model. Mixed cultures were incubated for 24 h with 0.125 to 512 micro g of CZX per ml or 0.125 to 2,048 micro g of PIP or PT per ml. Mice were treated every 2 h for 24 h with CZX at 6 to 1,536 mg/kg/day or with PIP or PT at 24 to 6,144 mg/kg/day starting 30 min before inoculation with different B. fragilis-E. cloacae combinations. There was a good correlation between the in vitro and in vivo activities of the antibiotics and their MICs obtained with high inocula (10(8) CFU/ml). The respective 50% effective doses (milligrams per kilogram per day) with B. fragilis and E. cloacae 22491 were 771 and 521 for CZX, 416 and 643 for PIP, and 85 and 554 for PT, and with the B. fragilis-E. cloacae 032349 combination, they were 81 and 21 for CZX and 77 and 766 for PT. Resistant mutants of E. cloacae 22491 were preferentially selected in vitro with 2 to 64 micro g of CZX per ml and in vivo with CZX at 12 to 384 mg/kg/day. There was no preferential selection of CZX-resistant B. fragilis or E. cloacae 032349. For CZX-resistant E. cloacae 22491, we found a 16- to 512-fold increase in the MIC of CZX and increased MICs of other expanded-spectrum cephalosporins, owing in part to the production of a stably derepressed cephalosporinase. In vitro and in vivo, PT did not select resistant mutants of E. cloacae and B. fragilis. Results demonstrate the adverse microbiological outcome of choosing an expanded-spectrum cephalosporin like CZX for empirical treatment of mixed infections involving a susceptible Enterobacter strain

Hip Strength Influences Ground Reaction Force Attenuation on a Side Leap in Collegiate Dancers

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Investigating Bilateral Asymmetries in Joint Angular Motion of the Lower Limb During Running

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Landing Differences in Ground Reaction Force and Kinematics between Collegiate Female Basketball Players and Dancers

Bravo-Pontrelli, E., Rubin, K., Stearne, D. West Chester University, West Chester, PA Purpose: Altered landing mechanics may decrease force attenuation capacity at ground contact and expose the athlete to non-contact knee injuries. Jump landing strategies exhibited by dancers during training and performance may reduce injury risk by improving alignment through the knee. The purpose of this study was to examine differences between collegiate female basketball players and dancers on hip and knee strength, sagittal and coronal plane lower extremity kinematics and ground reaction forces on single-leg drop landings and drop jumps from 30 cm and to evaluate Reactive Strength Index (RSI) as a functional measure of effective landing strategy and energy transfer on a countermovement. Methods: Four healthy female dancers from a university dance group (age = 20.5 + 1.3 years, height = 164 + 5 cm, weight = 60 + 8.2 kg) and four healthy NCAA Division II female basketball players (age = 20.5 + 1.9 years, height = 169.7 + 7.4 cm, weight = 66 + 8 kg), each with at least 7 years of competitive experience in their respective disciplines, participated. A cross-sectional design was used. Independent variable was training modality (dance or basketball). Dependent variables were isometric strength, for hip extensors, flexors, abductors, adductors, lateral and medial rotators, and knee extensors and flexors, RSI, ground reaction forces and sagittal and coronal plane kinematics. Results: Independent t-tests revealed that dancers exhibited greater knee flexion (p = .014, t = 3.43) on the single-leg drop landing and lower knee valgus angle (p = .014, t = 3.45) on the drop jump task, compared to basketball players. No other differences were statistically significant. Conclusion: Although normalized strength differences between groups did not exist, dancers appeared to demonstrate a softer landing strategy through greater knee flexion and more effectively maintained neutral alignment in the coronal plane at ground contact. Further, since RSI scores did not differ between groups, the safer landing strategy exhibited by dancers did not significantly reduce countermovement performance and thus indicates that dance training principles may show potential for application to more conventional sport training programs aimed at knee injury risk reduction. Research funded by a West Chester University Student-Faculty Research Grant

Video Measures of Running Ground Contact Times and Vertical Ground Reaction Forces

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The Effects of an Adjustable Workout System on Performance Gains in Collegiate Lacrosse Athletes

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Excessive Foot Mobility Enhances Static Stability under Visual Perturbation

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