Reliability of unipodal and bipodal counter movement jump landings in a recreational male population

Movement patterns during landing have been suggested to be related to injury risk. The purpose of this study was to determine the inter-session reliability of kinematic variables and ground reaction forces during landing in a population of male recreational athletes after a counter movement jump. Both unipodal and bipodal landings were evaluated. Furthermore, the possibility to improve landing reliability with a verbal instruction was also studied. Twenty-four male volunteers with no history of lower extremity trauma were randomly assigned to two groups (with and without verbal landing instruction). An optoelectronic 3D system and force plates were used to measure the lower limb joint angles and the ground reaction forces during landing. Intraclass correlation values show moderate to excellent inter-session reliability for the bipodal task (ICC average: 0.80, range: 0.46–0.97) and poor to excellent reliability for the unipodal task (ICC average: >0.75, range: 0.20–0.95). However, large standard errors of measurement values at the ankle joint at impact (27.6?±?11.5°) and for the vertical ground reaction forces (394?±?1091 N) show that some variables may not be usable in practice. The verbal instruction had a negative effect on the reliability of unipodal landing but improved the reliability of bipodal landing. These findings show that the reliability of a landing task is influenced by its motor complexity as well as the instruction given to the subject.     

The prevalence and risk indicators of symptoms of common mental disorders among current and former Dutch elite athletes

The aim of the study was to determine the prevalence and comorbidity of symptoms of common mental disorders (distress, anxiety/depression, sleep disturbance, eating disorders, adverse alcohol use) among current and former Dutch elite athletes, and to explore the inference between potential risk indicators (severe injury, surgery, life events, sport career dissatisfaction, social support) and the outcomes measures under investigation. Cross-sectional analyses were conducted on baseline questionnaires from an ongoing prospective cohort study among 203 current and 282 former elite Dutch athletes (response rate: 28% among current athletes and 95% among former athletes). Based on validated scales, an electronic questionnaire was set up and distributed. Prevalence (4-week) ranged from 6% for adverse alcohol use to 45% for anxiety/depression among current elite athletes, and from 18% for distress to 29% for anxiety/depression among former elite athletes. A higher number of past severe injuries, higher number of past surgeries, higher number of recent life events, higher level of career dissatisfaction and lower level of social support were related to the occurrence of symptoms of common mental disorders among both current and former elite athletes. On average, the 4-week prevalence of common mental disorders as shown in our study among current and former Dutch elite athletes were similar to the ones found among athletes from other sports disciplines and does compare with the lifetime prevalence estimates in the general population of the Netherlands.     

The Influence of Reflection on Employee Psychological Empowerment: Report of an Exploratory Workplace Field Study

ABSTRACT The study examined the influences of reflection on the self‐perception of empowerment in the workplace. The convenience sample consisted of non‐management knowledge workers at a software company headquartered in the United States. A pretest, posttest control group design was used. The experimental group kept guided journals of their learning activities for three months. Immediately prior to and following the journaling period, both groups completed Spreitzer's Psychological Empowerment Scale. Though no significant within‐group results were found, between‐group analyses revealed that participants who kept guided journals were able to maintain a high level of psychological empowerment, even during turbulent periods at the host organization, while the psychological empowerment of the control group worsened. The results suggest that reflection through guided journaling may sustain the perception of empowerment for individuals who already possess a fairly high level of psychological empowerment. The paper concludes with implications for further research.     

A prospective study of pedometer-determined physical activity and physical self-perceptions in children

There have been limited prospective studies investigating physical activity and physical self-perceptions in children. In this investigation, mean steps/day did not significantly change from late elementary to junior high for either boys or girls; however; boys accumulated more steps both at baseline and follow-up. Physical self-perception measures were significantly related to changes in steps/day and accounted for 21% (15% adjusted) of the variance after controlling for demographic/biological variables, R2 change = .21, adjusted R2 change = .15, F (5,88) = 4.66, p < .001. Sport competence emerged as the most important predictor t (88) = -3.76, p < .001, and was inversely related to physical activity change. The lack of opportunities to participate in sport activities normally found at the onset of adolescence may help explain this unexpected result.     

Water-repellent and biocide treatments: Assessment of the potential combinations

It is a common practice to use several chemical products during restoration projects of monuments or sculptures. However, care must be taken when combining the products to avoid a misuse. For example, it is well-known that applying a biocide on stone before a water-repellent leads to a diminishment of the hydrophobic effect of the treatment. But the application of biocide after a water-repellent treatment has been poorly analysed, although studies have proven that the stone looses its hydrophobicity after the application of the biocide. Henceforth, this study investigates the effects of biocide application on a water-repellent film and focuses on the possibilities to restore the efficiency of the previous water-repellent treatment (after the application of the biocide). At first, the tests were performed on glass slides to understand the mechanisms, with the subsequent results revealing that the biocide product deposits on the water-repellent film. Then, the study focuses on determining methods to remove the remains of biocide on limestone samples, previously treated with a water-repellent. The water-repellent used in the study is an alkylpolysiloxane, Rhodorsil H224 from Rhodia.