Preseason Functional Test Scores are Associated with Future Sports Injury in Female Collegiate Athletes

Brumitt, J, Heiderscheit, B, Manske, R, Niemuth, PE, Mattocks, A, and Rauh, MJ. Preseason functional test scores are associated with future sports injury in female collegiate athletes. J Strength Cond Res 32(6): 1692–1701, 2018—Recent prospective cohort studies have reported preseason functional performance test (FPT) measures and associations with future risk of injury; however, the findings associated with these studies have been equivocal. The purpose of this study was to determine the ability of a battery of FPTs as a preseason screening tool to identify female Division III (D III) collegiate athletes who may be at risk for a noncontact time-loss injury to the lower quadrant (LQ = low back and lower extremities). One hundred six female D III athletes were recruited for this study. Athletes performed 3 FPTs: standing long jump (SLJ), single-leg hop (SLH) for distance, and the lower extremity functional test (LEFT). Time-loss sport-related injuries were tracked during the season. Thirty-two (24 initial and 8 subsequent) time-loss LQ injuries were sustained during the study. Ten of the 24 initial injuries occurred at the thigh and knee. At-risk athletes with suboptimal FPT measures (SLJ #79% ht; (B) SLH #64% ht; LEFT $118 seconds) had significantly greater rates of initial (7.2 per 1,000 athletic exposures [AEs]) and total (7.6 per 1,000 AEs) time-loss thigh or knee injuries than the referent group (0.9 per 1,000 AEs; 1.0 per 1,000 AEs, respectively). At-risk athletes were 9 times more likely to experience a thigh or knee injury (odds ratio [OR] = 9.7, confidence interval [CI]: 2.3–39.9; p = 0.002) than athletes in the referent group. At-risk athletes with a history of LQ sports injury and lower off-season training habits had an 18-fold increased risk of a time-loss thigh or knee injury during the season (adjusted OR = 18.7, CI: 3.0–118.1; p = 0.002). This battery of FPTs appears useful as a tool for identifying female D III athletes at risk of an LQ injury, especially to the thigh or knee region

One-electron self energies and spectral functions for the t-J model in the large-N limit

Using a recently developed perturbative approach, which considers Hubbard operators as fundamental excitations, we have performed electronic self-energy and spectral function calculations for the $t-J$ model on the square lattice. We have found that the spectral functions along the Fermi surface are isotropic, even close to the critical doping where the $d$-density wave phase takes place. Fermi liquid behavior with scattering rate $\sim \omega^2$ and a finite quasiparticle weight $Z$ was obtained. $Z$ decreases with decreasing doping taking low values for low doping. Results are compared with other ones, analytical and numerical like slave-boson and Lanczos diagonalization finding agreement. We discuss our results in the light of recent $ARPES$ experiments in cuprates.Comment: 10 pages, 9 figures, accepted for publication in Phys. Rev.

Renormalization of the elementary excitations in hole- and electron-doped cuprates due to spin fluctuations

Extending our previous studies we present results for the doping-, momentum-, frequency-, and temperature- dependence of the kink-like change of the quasiparticle velocity resulting from the coupling to spin fluctuations. In the nodal direction a kink is found in both the normal and superconducting state while in the antinodal direction a kink occurs only below $T_c$ due to the opening of the superconducting gap. A pronounced kink is obtained only for hole-doped, but not for electron-doped cuprates and is characteristically different from what is expected due to electron-phonon interaction. We further demonstrate that the kink structure is intimately connected to the resonance peak seen in inelastic neutron scattering. Our results suggest similar effects in other unconventional superconductors like ${Sr}_2{RuO}_4$.Comment: revised version, 12 pages, 19 figures. accepted for publication in PR

Dispersion and damping of zone-boundary magnons in the noncentrosymmetric superconductor CePt3Si

Inelastic neutron scattering (INS) is employed to study damped spin-wave excitations in the noncentrosymmetric heavy-fermion superconductor CePt3Si along the antiferromagnetic Brillouin-zone boundary in the low-temperature magnetically ordered state. Measurements along the (1/2 1/2 L) and (H H 1/2-H) reciprocal-space directions reveal deviations in the spin-wave dispersion from the previously reported model. Broad asymmetric shape of the peaks in energy signifies strong spin-wave damping by interactions with the particle-hole continuum. Their energy width exhibits no evident anomalies as a function of momentum along the (1/2 1/2 L) direction, which could be attributed to Fermi-surface nesting effects, implying the absence of pronounced commensurate nesting vectors at the magnetic zone boundary. In agreement with a previous study, we find no signatures of the superconducting transition in the magnetic excitation spectrum, such as a magnetic resonant mode or a superconducting spin gap, either at the magnetic ordering wavevector (0 0 1/2) or at the zone boundary. However, the low superconducting transition temperature in this material still leaves the possibility of such features being weak and therefore hidden below the incoherent background at energies ~0.1 meV, precluding their detection by INS

Cosmography and the redshift drift in Palatini f(R)f({\cal R}) theories

We present an application to cosmological models in $f({\cal R})$ theories within the Palatini formalism of a method that combines cosmography and the explicit form of the field equations in the calculation of the redshift drift. The method yields a sequence of constraint equations which lead to limits on the parameter space of a given $f({\cal R})$-model. Two particular families of $f({\cal R})$-cosmologies capable of describing the current dynamics of the universe are explored here: (i) power law theories of the type $f({\cal R})={\cal R}-\beta /{\cal R}^n$, and (ii) theories of the form $f({\cal R})={\cal R}+\alpha \ln{{\cal R}} -\beta$. The constraints on $(n,\beta)$ and $(\alpha,\beta)$, respectively, limit the values to intervals that are narrower than the ones previously obtained. As a byproduct, we show that when applied to General Relativity, the method yields values of the kinematic parameters with much smaller errors that those obtained directly from observations.Comment: 7 pages, 2 figure

Lower Extremity Functional Tests and Risk of Injury in Division III Collegiate Athletes

Purpose/Background: Functional tests have been used primarily to assess an athlete’s fitness or readiness to return to sport. The purpose of this prospective cohort study was to determine the ability of the standing long jump (SLJ) test, the single-leg hop (SLH) for distance test, and the lower extremity functional test (LEFT) as preseason screening tools to identify collegiate athletes who may be at increased risk for a time-loss sports-related low back or lower extremity injury. Methods: A total of 193 Division III athletes from 15 university teams (110 females, age 19.1 ± 1.1 y; 83 males, age 19.5 ± 1.3 y) were tested prior to their sports seasons. Athletes performed the functional tests in the following sequence: SLJ, SLH, LEFT. The athletes were then prospectively followed during their sports season for occurrence of low back or LE injury. Results: Female athletes who completed the LEFT in 118 s were 6 times more likely (OR=6.4, 95% CI: 1.3, 31.7) to sustain a thigh or knee injury. Male athletes who completed the LEFT in 100 s were more likely to experience a time-loss injury to the low back or LE (OR=3.2, 95% CI: 1.1, 9.5) or a foot or ankle injury (OR=6.7, 95% CI: 1.5, 29.7) than male athletes who completed the LEFT in 101 s or more. Female athletes with a greater than 10% side-to-side asymmetry between SLH distances had a 4-fold increase in foot or ankle injury (cut point: \u3e10%; OR=4.4, 95% CI: 1.2, 15.4). Male athletes with SLH distances (either leg) at least 75% of their height had at least a 3-fold increase (OR=3.6, 95% CI: 1.2, 11.2 for the right LE; OR=3.6, 95% CI: 1.2, 11.2 for left LE) in low back or LE injury. Conclusions: The LEFT and the SLH tests appear useful in identifying Division III athletes at risk for a low back or lower extremity sports injury. Thus, these tests warrant further consideration as preparticipatory screening examination tools for sport injury in this population. Clinical Relevance: The single-leg hop for distance and the lower extremity functional test, when administered to Division III athletes during the preseason, may help identify those at risk for a time-loss low back or lower extremity injury

Q2Q_2-free families in the Boolean lattice

For a family $\mathcal{F}$ of subsets of [n]=\{1, 2, ..., n} ordered by inclusion, and a partially ordered set P, we say that $\mathcal{F}$ is P-free if it does not contain a subposet isomorphic to P. Let $ex(n, P)$ be the largest size of a P-free family of subsets of [n]. Let $Q_2$ be the poset with distinct elements a, b, c, d, a<b, c<d; i.e., the 2-dimensional Boolean lattice. We show that $2N -o(N) \leq ex(n, Q_2)\leq 2.283261N +o(N),$ where $N = \binom{n}{\lfloor n/2 \rfloor}$. We also prove that the largest $Q_2$-free family of subsets of [n] having at most three different sizes has at most 2.20711N members.Comment: 18 pages, 2 figure

Influence of long-range coulomb interaction and on-site hubbard repulsion on the formation of d-wave copper-pairing in High- Tc cuprates

We develop a diagram technique for the self-consistent treatment of the long-range Coulomb interaction and on-site Hubbard repulsion in the normal and superconducting state of high7-4 cuprates. The resultant analytical expression for the "screened" matrix elements taking into account long-range and on-site repulsion has been derived. In particular, it accounts for processes with and without spin-flip due to an exchange of spin and charge density fluctuations. Furthermore, we derive the expressions for the normal and anomalous self-energy parts near the superconducting transition temperature Tc that takes into account the vertex corrections including crossing diagrams. The contribution of the crossing parts is taken within the ladder approximation (similar to Fluctuation-Exchange approximation) where the role of Hubbard on-site interaction is replaced by the Coulomb matrix element with a spin-flip averaged over the momentum. Finally, the developed scheme allows to analyze the formation of d-wave superconductivity and its stability in presence of the long-range Coulomb repulsion within a self-consistent anisotropic Eliashberg-like approach. © 2004 Plenum Publishing Corporation