On the universality of the global slope -- anisotropy inequality

Recently, some intriguing results have lead to speculations whether the central density slope -- velocity dispersion anisotropy inequality (An & Evans) actually holds at all radii for spherical dynamical systems. We extend these studies by providing a complete analysis of the global slope -- anisotropy inequality for all spherical systems in which the augmented density is a separable function of radius and potential. We prove that these systems indeed satisfy the global inequality if their central anisotropy is $\beta_0\leq 1/2$. Furthermore, we present several systems with $\beta_0 > 1/2$ for which the inequality does not hold, thus demonstrating that the global density slope -- anisotropy inequality is not a universal property. This analysis is a significant step towards an understanding of the relation for general spherical systems.Comment: 8 pages, 1 figure, accepted for publication in Ap

Some factors affecting urinary calculus formation in weaned lambs

The objective of undertaking this study was to examine the relationship between various dietary factors (physical form of the diet, dietary nitrogen level and source, different levels and combinations of calcium, magnesium and phosphorus) and urinary calculus formation in lambs weaned at 4 weeks of age.The first experiment was an incomplete factorial utilising 64 lambs. The results obtained showed that neither pelleting the diet, dietary nitrogen level nor source initiated calculus formation. Pelleting the diet increased mineral digestibility and subsequently urinary mineral excretion was increased. Supplementation of the diet with urea or protein reduced the concentration of urinary minerals although phosphorus values for the urea-fed animals were much lower than those for the protein-fed animals.The second experiment was a complete factorial utilising 64 lambs. The results indicated that supplements of both calcium and magnesium were likely to reduce calculus formation whereas phosphorus supplements enhanced urinary excretion of phosphorus. Calculus formation was not associated with any particular dietary combination of minerals but was more a function of time postweaning. There was a distinct time effect in relation to urinary mineral concentration post¬ weaning: urinary mineral concentrations were very high (e.g. phosphorus, 95,6mg/lOOml) in the immediate postweaning period (2 to 4 weeks) but decreased to comparatively low levels (e.g. phosphorus, 40.9mg/100ml) at 7 to 9 weeks postweaning. Calculi occurred when urinary mineral con¬ centrations were at their highest in the immediate post¬ weaning period. Autopsy findings indicated calculi were of renal origin and composed largely of magnesium phosphate.The results of Experiment II indicated that the transitional period at weaning was important in relation to calculus formation. The water economy at this time was measured in Experiment III and it was found that water intake and urine output were at least halved postweaning. Also, during the preweaning period, water retention was a function of water intake whereas postweaning, it was under renal control. This control was imprecise over the immediate 10 day postweaning period and it appeared that this might be the time when calculus formation was initiated.An attempt to supplement water intake via feeding tubes (Experiment IV) during the postweaning period was unsuccess¬ ful as lambs regurgitated the tubes. Another experiment (Experiment V) was undertaken in which additional water was supplied to lambs via cannulae inserted in the reticulorumen. The water economy of these lambs was compared with those weaned normally. The results obtained were similar to those in Experiment III although there was no evidence of water restriction, in the normally weaned lambs, causing renal deposits associated with calculus formation.The results obtained and their implications in the aetiology and prevention of urolithiasis are discussed

Variations in the Relationship Between the Frequency Content of EMG Signals and the Rate of Torque Development in Voluntary and Elicited Contractions

Our purpose was to characterize the relationship between EMG mean power frequency (MPF) or median frequency (MF) and rate of torque development in voluntary ballistic and electrically elicited isometric contractions. Twenty-three healthy adults participated in two sets of experiments performed on elbow flexor muscles. For Experiment 1, subjects were asked to generate voluntary ballistic contractions by reaching four different target torque levels (20, 40, 60 and 100% of the maximal voluntary contraction (MVC)) as fast as they could. For Experiment 2, electrical (M-waves) and mechanical (twitches) responses to electrical stimulation of the nerves supplying the biceps brachii and brachioradialis muscles were recorded with the subjects at rest and with a background isometric contraction of 15% MVC. MPF, MF and rate of torque development (% MVC/s) were calculated for both voluntary and elicited contractions. Significant positive correlations were observed between MPF and rate of torque development for the voluntary contractions, whereas significant negative correlations were observed between the two variables for elicited contractions. This suggests that factors other than muscle fiber composition influence the frequency content of EMG signals and/or the rate of torque development, and that the effect of these factors will vary between voluntary and elicited contractions. 2002 Elsevier Science Ltd. All rights reserved

In-Season Rehabilitation Program Using Blood Flow Restriction with Therapy for Two Decathletes with Patellar Tendinopathy: A Case Report

Background and Purpose: Patellar tendinopathy is an overuse injury experienced primarily by athletes; especially athletes who participate in sports that involve frequent jumping. Therapeutic exercise is the primary conservative treatment for patients with this condition. However, some patients with patellar tendinopathy may be unable to tolerate the loading that occurs during exercise. The use of blood flow restriction (BFR) therapy for patients with patellar tendinopathy may allow the athlete to exercise with a lower load while still experiencing the physiological benefits associated with training at a higher intensity. The purpose of this case report was to detail the outcomes from a rehabilitation program utilizing BFR for two collegiate decathletes with patellar tendinopathy. Study Design: Case Report Case Descriptions and Interventions: Two NCAA Division III freshmen collegiate decathletes with a history of left knee pain prior to college and who had been complaining of increasing pain during the initial month of track practices. Findings from the musculoskeletal examinations included left sided lower extremity weakness, pain during functional testing, pain when palpating the left patellar tendon, and VISA-P scores less than 80. Ultrasound imaging at baseline revealed thickened tendons on the left with hypoechoic regions. Both athletes participated in 20 therapy sessions consisting of therapeutic exercises performed with BFR. Outcomes: Both athletes experienced improvements in pain scores, increases in lower extremity strength, improved functional test performance, higher VISA-P scores, and improvements in tendon size and appearance as measured by diagnostic ultrasound. Conclusion: Both athletes experienced improvements with the BFR-based therapeutic exercise program and were able to compete throughout the track season. The use of BFR may allow patients who are unable to tolerate exercise due to pain an alternative approach during rehabilitation. Future research should compare therapeutic exercise programs for this condition with and without BFR. Level of Evidence: Level

Current Concepts of Muscle and Tendon Adaptation to Strength and Conditioning

Injuries to the muscle and/or associated tendon(s) are common clinical entities treated by sports physical therapists and other rehabilitation professionals. Therapeutic exercise is a primary treatment modality for muscle and/or tendon injuries; however, the therapeutic exercise strategies should not be applied in a “one-size-fits-all approach”. To optimize an athlete’s rehabilitation or performance, one must be able to construct resistance training programs accounting for the type of injury, the stage of healing, the functional and architectural requirements for the muscle and tendon, and the long-term goals for that patient. The purpose of this clinical commentary is to review the muscular and tendinous adaptations associated with strength training, link training adaptations and resistance training principles for the athlete recovering from an injury, and illustrate the application of evidence-based resistance training for patients with a tendinopathy

Validity and Comparisons of Tibiofemoral Angles and Translations using a New Femoral Tracking Device (FTD) during Walking

First, this study compares tibiofemoral motion during walking using a new femoral tracking device (FTD) and bone mounted markers in a single subject (n=1). The results suggest errors ofn=13). The results suggest similar tibiofemoral angles in the sagittal and frontal planes using the two methods (average root mean square (RMS) differences

Effects of a Parkinson\u27s Disease Community Exercise Group on Self Reported Promis Measures

Parkinson’s Disease (PD) is an upper motor neuron disorder that results in bradykinesia, rigidity, shuffling gait patterns, and balance impairments. Non-motor issues include depression, anosmia, GI issues, pain, and more. Approximately 90,000 people in the U.S. are diagnosed every year. Hypothesis: Self efficacy and satisfaction roles will positively correlate with participation in the 6 week exercise program

Generation of potential/surface density pairs in flat disks Power law distributions

We report a simple method to generate potential/surface density pairs in flat axially symmetric finite size disks. Potential/surface density pairs consist of a ``homogeneous'' pair (a closed form expression) corresponding to a uniform disk, and a ``residual'' pair. This residual component is converted into an infinite series of integrals over the radial extent of the disk. For a certain class of surface density distributions (like power laws of the radius), this series is fully analytical. The extraction of the homogeneous pair is equivalent to a convergence acceleration technique, in a matematical sense. In the case of power law distributions, the convergence rate of the residual series is shown to be cubic inside the source. As a consequence, very accurate potential values are obtained by low order truncation of the series. At zero order, relative errors on potential values do not exceed a few percent typically, and scale with the order N of truncation as 1/N**3. This method is superior to the classical multipole expansion whose very slow convergence is often critical for most practical applications.Comment: Accepted for publication in Astronomy & Astrophysics 7 pages, 8 figures, F90-code available at http://www.obs.u-bordeaux1.fr/radio/JMHure/intro2applawd.htm

Relationship Between Static Mobility of the First Ray and First Ray, Midfoot, and Hindfoot Motion During Gait

The relationship between a static measure of dorsal first ray mobility and dynamic motion of the first ray, midfoot, and hindfoot during the stance phase of walking was investigated in healthy, asymptomatic subjects who represented the spectrum of static flexibility. Static first ray mobility of 15 subjects was measured by a load cell device and ranged from stiff (3.1 mm) to lax (8.0 mm). Using three-dimensional motion analysis, mean first ray dorsiflexion/eversion and mid-/hindfoot eversion peak motion, time-to-peak, and eversion excursion were evaluated. Subjects with greater static dorsal mobility of the first ray demonstrated significantly greater time-topeak hindfoot eversion and eversion excursion (p \u3c .01), and midfoot peak eversion and eversion excursion (p \u3c .01). No significant association was found between static first ray mobility and first ray motion during gait. This research provides evidence that the dynamic response of the foot may modulate the consequences of first ray mobility and that compensory strategies are most effective when static measures of dorsal mobility are most extreme

What Maximum Ankle Torque is Appropriate for Training Patients with Non-insertional Achilles Tendinopathy?

Background and Purpose: The capacity of the Achilles tendon during a 1-repetition eccentric maximum contraction is largely unknown. This study examined the maximum ankle torque during a concentric/ eccentric heel raise/lowering task and while running in healthy individuals and participants with chronic Achilles tendinopathy. These findings were applied to a 10-week training program for a patient with chronic Achilles tendinopathy. Methods: A total of 13 subjects (9 healthy and 4 with Achilles tendinopathy) participated in this study. Subjects were asked to perform a maximum eccentric contraction wearing a weighted vest while collecting 3-dimensional biomechanical variables. Subjects also ran along an instrumented runway to assess torque at the ankle joint. All participants completed VISA-A Outcomes: On the VISA-A, subjects with Achilles tendinopathy (AT) scored on average 28 points less than the healthy controls and were 27% weaker. The peak ankle torque during a single leg lowering task and running was 3.1 Nm/kg and appeared similar between controls and participants with chronic AT. Findings of the study when applied in a 10-week high load eccentric rehabilitation program demonstrated improved tendon characteristics and VISA-A score. Conclusion: Unhealthy tendons likely can tolerate high loads during rehabilitation and AT programs should consist of progressive resistive exercises instead of movements that emphasize repetitions