Is there a low-back cost to hip-centric exercise? Quantifying the lumbar spine joint compression and shear forces during movements used to overload the hips

The aim of this study was to quantify joint compression and shear forces at L4/L5 during exercises used to overload the hips. Nine men performed 36 "walking" trials using two modalities: (1) sled towing and (2) exercise bands placed around the ankles. Participants completed forward, backward, and lateral trials with bent and straight legs at three separate loads. Surface electromyography (EMG) was recorded bilaterally from eight torso and thigh sites, upper body and lumbar spine motion were quantified, and hand forces were measured. An EMG-driven musculoskeletal model was used to estimate the muscular contribution to joint compression and shear. Peak reaction, muscle and joint compression and shear forces, and peak gluteus medius and maximus activity were calculated. Significant differences were noted in each dependent measure; however, they were dependent on direction of travel, leg position, and load. The highest joint compression and shear forces for the sled and band conditions were 4378 N and 626 N, and 3306 N and 713 N, respectively. In general, increasing the band tension had little effect on all dependent measures, although a load-response was found during the sled conditions. Before using any exercise to improve hip function, the potential benefits should be weighed against "costs" to neighbouring joints.     

Neural adaptations with sport-specific resistance training in highly skilled athletes

The aim of this study was to assess the effects of variations in the volume and intensity of resistance training in highly skilled athletes on neural adaptive mechanisms: the maximality and pattern of neural drive. The maximality of muscle activation was measured using a high-resolution sample and hold amplifier to record interpolated twitches. The pattern of neural drive was measured by analysing isometric torque-time curves and electromyographic (EMG) characteristics during the performance of rapid isometric contractions at maximal effort. The volume and intensity of training were varied at 4-weekly intervals to systematically emphasize the development of strength, power and motor performance in 14 highly skilled track and field athletes (e.g. discus, hammer, javelin, shot put and weight). Knee extension strength increased significantly by 15% during steady maximal isometric contractions and by 24% during rapid isometric contractions at maximal effort after the 16-week training programme (P < 0.05). Increases in EMG amplitude and rate of EMG activation indicated that improvements to the pattern of neural drive occurred with sport-specific resistance training (P < 0.05). The maximality and pattern of neural drive did not change in the control group.     

Initial Validity Evidence for the State Mindfulness Scale for Physical Activity With Youth

Experiencing mindfulness during movement-based interventions (e.g., yoga) may help support adaptive physical activity motivation processes in youth. However, there is currently no measure for assessing state mindfulness with youth within the context of physical activity. The purpose of this study was to qualitatively and quantitatively evaluate a measure of state mindfulness for physical activity in youth. In study one, cognitive interviews with youth (N = 15) ages 8–13 evaluated the State Mindfulness Scale for Physical Activity item comprehension and preference for developmentally worded modifications. Results suggest that problems with item comprehension were more likely in youth younger than 10. In study two, the State Mindfulness Scale for Physical Activity, or a modified version, was administered randomly to middle-school students (N = 481). Internal consistency reliability, confirmatory factor analyses, model-based reliability omega, and correlations with theoretically relevant variables combined with the qualitative evidence provided stronger initial support for the use of the original State Mindfulness Scale for Physical Activity with middle-school students.     

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.     

西方美术的阴与阳

你能够闭着眼睛练习绘画吗？你用染发剂在浴巾上作画的本领又如何呢？ 对很多中国人来说，这样的问题听起来可能很荒唐．但是对于像我这样的西方人来说．这只是我们传统美术教育的一部分。相比技巧和细节，当代西方人越来越看重艺术的独特性和创造性。这种价值体系鼓励学生多去试验．不要畏惧失败。     

Cheating Around the World: A Cross-national Analysis of Principal Reported Cheating

An increasing problem of great concern for academic institutions around the world is the pervasiveness of academic cheating among students. However, there is a dearth of prior research on cheating in cross-national contexts. The present study examines the relationships between structural measures of strain and principals’ reports of problematic cheating in schools across 35 nations, derived from the 2007 Trends in International Math and Science Studies survey. The study employs multilevel logistic regression analysis to evaluate whether indicators of economic disadvantage, educational achievement, and educational inequalities influence the level of problematic cheating reported by school principals cross-nationally. Additionally, we identify which socioeconomic and demographic characteristics of nation-states are most related to perceptions of problematic academic cheating as reported by school principals. The findings indicate that schools with resource shortages, greater levels of economic disadvantage, and those with larger national average grade sizes experience higher levels of problematic cheating.     

How accurately does the VIVO Harvester reflect actual Clinical and Translational Sciences Award–affiliated faculty member publications?

Objective:

The research tested the accuracy of the VIVO Harvester software in identifying publications authored by faculty members affiliated with a National Institutes of Health Clinical and Translational Sciences Award (CTSA) site.

Methods:

Health sciences librarians created “gold standard” lists of references for the years 2001 to 2011 from PubMed for twenty-five randomly selected investigators from one CTSA site. These gold standard lists were compared to the same twenty-five investigators'' reference lists produced by VIVO Harvester. The authors subjected the discrepancies between the lists to sensitivity and specificity analyses.

Results:

The VIVO Harvester correctly identified only about 65% of the total eligible PubMed references for the years 2001–2011 for the CTSA-affiliated investigators. The identified references produced by VIVO Harvester were precise yet incomplete. The sensitivity rate was 0.65, and the specificity rate was 1.00.

Conclusion:

While the references produced by VIVO Harvester could be confirmed in PubMed, the VIVO Harvester retrieved only two-thirds of the required references from PubMed. National Institutes of Health CTSA sites will need to supplement VIVO Harvester–produced references with the expert searching skills of health sciences librarians.

Implications:

Health sciences librarians with searching skills need to alert their CTSA sites about these deficiencies and offer their skills to advance their sites'' missions.     

Patterns of barbell acceleration during the snatch in weightlifting competition

The purpose of this study was to determine the association between weightlifting performance and vertical barbell acceleration patterns. Barbell kinematic time-series data were tracked from 18 snatches from six weightlifters during a regional weightlifting competition. These data were used to calculate vertical barbell accelerations. Time-series data were normalised to 100% of lift phase, defined as the time interval between barbell lift-off and maximum height of the barbell during each snatch lift. The time-series data were then entered into a pattern recognition algorithm that extracted principal patterns and calculated principal pattern scores. Body mass-normalised lift weight, which was used to quantify weightlifting performance, was significantly correlated (r = 0.673; P = 0.033) with a pattern that captured a difference in peak vertical barbell acceleration between the transition and the second pull phase. This correlation indicated that barbell acceleration profiles of higher weight snatch lifts were characterised by smaller decreases in acceleration during the second knee bend and smaller peak acceleration during the second pull phase. Weightlifting coaches and sports scientist should monitor and track vertical acceleration of the barbell, with focus on acceleration profiles that limit (1) deceleration during the transition phase between the first and second pull and (2) peak acceleration during the second pull phase of the snatch.     

From the Editor

Educational Assessment, Evaluation and Accountability -