Shoulder joint kinetics of the elite wheelchair tennis serve

Background

The shoulder is a key joint in wheelchair locomotion and commonly implicated in injury among virtually all wheelchair populations. In tennis, quantification of the shoulder joint kinetics that characterise the wheelchair serve could enhance injury prevention and rehabilitation practices as well as assist coaches evaluate the efficacy of their current technical instruction.

Methods

A 12‐camera, 250 Hz Vicon motion analysis system (Oxford Metrics Inc., UK) recorded the 3D flat (WFS) and kick serve (WKS) motions of two male top 30‐ranked international wheelchair players. Mechanical comparisons between wheelchair players, as well as to the previously captured data of 12 high‐performance able‐bodied players executing the same types of serves, were undertaken.

Results

Without the benefit of a propulsive leg action, wheelchair players developed lower peak absolute (∼32 m/s) and horizontal (∼28 m/s) pre‐impact racquet velocities than able‐bodied players (∼42 m/s, ∼38 m/s). Wheelchair serve tactics nevertheless necessitated that higher pre‐impact horizontal and right lateral racquet velocities characterised the WFS (∼29 m/s, WKS: ∼26 m/s) and WKS (∼4 m/s, WFS: ∼11 m/s) respectively. The shoulder joint kinetics that contributed to the differential racquet velocity profiles were mostly developed independent of wheelchair serve type, but varied with and were likely related to the level and severity of spinal cord injury of the individual players.

Conclusions

Compared with able‐bodied players, wheelchair players experienced matching pre‐ and post‐impact shoulder joint loads, such that wheelchair and able‐bodied playing populations appear subject to similar shoulder joint injury risk.Current technical instruction of the wheelchair tennis serve is largely intuitive, guided to some extent by the substantiated biomechanical information describing the able‐bodied serve. The link between shoulder pain and wheelchair serve performance has similar origins, especially as wheelchair players, like their able‐bodied counterparts, commonly suffer from shoulder overuse injuries.^1,2 Delineation of the shoulder joint kinetics that contribute to the development of racquet velocity in the flat (WFS) and kick (WKS) wheelchair serves, and that are associated with shoulder joint injury, is thus important and was the focus of the present study. Further consideration of this data alongside the shoulder joint kinetics associated with able‐bodied serve performance provided for comparative comment.     

Unexpected effects of methylphenidate in attention-deficit/hyperactivity disorder reflect decreases in core/secondary symptoms and physical complaints common to all children

Abstract Hypotheses concerning unexpected, psychostimulant-related effects reported in previous studies were examined by separating behavioral/physical complaints highly specific to methylphenidate (MPH) from those that (a) may mimic core/secondary symptoms of the disorder, or (b) are commonly reported by unmedicated children in the general population. Sixty-five children with attention-deficit/hyperactivity disorder (ADHD) participated in a double-blind, placebo-controlled, within-subject (crossover) experimental design and received a placebo and four MPH doses in counterbalanced order following baseline assessment. Behavioral and physical complaints were significantly higher under baseline relative to placebo and the four immediate-release MPH conditions (5 mg, 10 mg, 15 mg, and 20 mg) across three symptom categories: ADHD core/secondary symptoms; symptoms commonly reported in the general population, including unmedicated children with ADHD; and symptoms highly specific to MPH. No significant differences were found among active drug conditions. Past unexpected findings of psychostimulant effects in ADHD may be due to the inclusion of scale items that reflect core/secondary features of ADHD and normally occurring behavioral/physical complaints in children.     

Truncated TrkB mediates the endocytosis and release of BDNF and neurotrophin-4/5 by rat astrocytes and schwann cells in vitro

Binding and cross-linking studies with radiolabeled neurotrophins demonstrate that cultured rat hippocampal astrocytes lack full-length TrkB, but do express high levels of truncated TrkB (tTrkB). In astrocytes and Schwann cells, tTrkB appears to have the novel function of mediating the endocytosis of neurotrophins into an acid-stable, Triton X-100 resistant intracellular pool that is released back into the medium in a temperature-dependent manner. Chloroquine treatment, trichloroacetic acid solubility, and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed that when incubated with astrocytes or Schwann cells for at least 48 h neither the intracellular nor the released neurotrophins were significantly degraded. The endocytosis and release of neurotrophins may represent a novel mechanism whereby neuroglia can regulate the local concentration of these neurotrophic factors for extended periods of time.     

A Prospective Study of Patient Reported Outcomes in Pancreatic and Peri-ampullary Malignancy

Background

The purpose of the present study was to describe the impact of treatment of pancreatic and peri-ampullary malignancy on patient reported outcomes (PRO). However, limited data are available describing the impact of curative or palliative therapy on pancreatic/peri-ampullary malignancy and quality of life.

Methods

Patients selected for pancreaticoduodenectomy (PD) completed the European Organisation for Research and Treatment of Cancer QLQ-C30 questionnaire pre-surgery and 6 weeks, 3, 6, 12, 18, and 24 months postoperatively. Patients selected for palliative treatments completed the same questionnaire before treatment and monthly thereafter. Mean scores and 95 % confidence intervals (CI) were calculated for functional scales. Symptom scales and single items were categorized as either minimal or severe, and they were reported as proportions of patients experiencing severe symptoms with 95 % CI.

Results

A total of 100 patients (53 planned PD, 47 palliative) were enrolled. Of the 53 patients planned for surgery, 12 had tumors that were unresectable and 41 underwent pancreatoduodenectomy (PD). Seven patients were excluded because of benign histology or concurrent malignancy. Baseline questionnaire compliance was 70 %. For those undergoing PD, there were 53 complications, 7 deaths at 1 year, and 14 deaths at 2 years. Post-surgery most functions and symptoms deteriorated. Recovery in global health and most symptoms occurred by 3 months, and functional scales recovered by 6 months. Recovery of PRO was maintained in the survivors at 2 years. Palliative patients had poorer function and more symptoms at baseline; however, poor follow-up questionnaire compliance prevented further analysis of this group.

Conclusions

Pancreaticoduodenectomy has a short-term negative impact on PRO that recovers within 6 months and is maintained at 2 years in survivors. Further work evaluating palliative and curative treatment in larger patient groups with disease-specific questionnaires is necessary.     

The Program for Rheumatic Independent Self-Management: A Pilot Evaluation

The 'Program for Rheumatic Independent Self-Management' (PRISM) is an interdisciplinary programme that integrates group education and individualised treatment using the principles of self-management, adult learning, case management and self-efficacy enhancement. This study is a before-after evaluation of 57 individuals who attended PRISM. Outcome measures were selected to measure self-efficacy, disability, pain and ability to cope. The mean self-efficacy score increased immediately following the programme and this improvement was maintained at 6-month follow-up. Disability decreased from baseline to 6-month follow-up. There was a decrease in the mean level of pain from post-class to 6-month follow-up. All of these changes were statistically significant. These preliminary findings suggest that PRISM may be effective in enhancing self-efficacy, and reducing disability and pain.     

Evaluation of teleradiology for interpretation of intravenous urograms

The diagnostic yield of a commercial teleradiology/picture archiving and communication system (ATT-Philips Comm View T/PACS) was evaluated for 100 urograms. A single image from each examination was digitized (2048 x 1684 x 12-bit pixels) and transmitted from a satellite hospital over a T-1 line using the T/PACS system. The video display of each digitized image was reviewed independently by four radiologists. The same four radiologists reviewed the original film images at a different time without knowledge of their T/PACS interpretation. There was no statistically significant difference in the sensitivity for clinical findings between T/PACS (86%) and film (89%). The false positive rate, however, was significantly higher with T/PACS than with film (44 versus 32 false positive findings per 100 films). We conclude that T/PACS of the type studied here demonstrates sufficient sensitivity for the detection of clinically important urographic findings in the emergency setting. A final reading of the original films is still necessary, however, to assure appropriate specificity.