Comparison of lower body specific resistance training on the hamstring to quadriceps strength ratios in men and women

In this study, we compared hamstring (H) and quadriceps (Q) strength changes in men and women, as well as changes in conventional and functional H:Q ratios following an identical 12-week resistance training program. An isokinetic dynamometer was used to assess 14 male and 14 female participants before and after the intervention, and conventional and functional H:Q ratios were calculated. Hamstring strength improved similarly in men and women, but improvement in quadriceps strength was significantly greater in men, while women showed only modest improvements. For the conventional and functional H:Q ratios, women showed significantly greater improvements than men. Both men and women were able to exceed the commonly recommended 0.6 conventional and 1.0 functional H:Q ratios after the 12-week lower-body resistance training program.     

Work-time profile,blood lactate concentration and rating of perceived exertion in the 1998 Greco-Roman Wrestling World Championship

The aim of this study was to examine work-time profiles, blood lactate concentrations and perceived exertion among Greco-Roman wrestlers in the 1998 World Championship. Forty-two senior wrestlers from nine nations were studied in 94 matches. Each match was recorded with a video camera (Panasonic AG 455, film rate: 25 Hz) and analysed for duration of work (wrestling) and rest (interrupt) periods. Blood lactate concentration was determined with an electrochemical device (Analox P-LM5) and a rating of perceived exertion scale (Borg) was used to estimate general exertion and exertion in the extremity and trunk muscles. The mean duration of the matches was 427 s (range 324-535 s), with mean durations of work and rest of 317 and 110 s, respectively. The mean periods of work and rest were 37.2 and 13.8 s, respectively. Mean blood lactate concentration was 14.8 mmol x 1(-1) (range 6.9-20.6). The difference in mean blood lactate concentration between the first- and final-round matches was not significant (P > 0.05). Blood lactate concentration was significantly higher (P < 0.04) in matches of long duration than in those of short duration. The mean general rating of perceived exertion for all matches was 13.8 according to the scale used. Most of the wrestlers (53.3%) perceived exertion to be highest in the flexors of the forearm, followed by the deltoids (17.4%) and the biceps brachii muscles (12.0%). In addition to a relatively high rating of perceived exertion in the arm muscles, this indicates a high specific load on the flexor muscles of the forearm.     

Work-time profile,blood lactate concentration and rating of perceived exertion in the 1998 Greco-Roman wrestling World Championship

The aim of this study was to examine work-time profiles, blood lactate concentrations and perceived exertion among Greco-Roman wrestlers in the 1998 World Championship. Forty-two senior wrestlers from nine nations were studied in 94 matches. Each match was recorded with a video camera (Panasonic AG 455, film rate: 25 Hz) and analysed for duration of work (wrestling) and rest (interrupt) periods. Blood lactate concentration was determined with an electrochemical device (Analox P-LM5) and a rating of perceived exertion scale (Borg) was used to estimate general exertion and exertion in the extremity and trunk muscles. The mean duration of the matches was 427 s (range 324-535 s), with mean durations of work and rest of 317 and 110 s, respectively. The mean periods of work and rest were 37.2 and 13.8 s, respectively. Mean blood lactate concentration was 14.8 mmol · l -1 (range 6.9-20.6). The difference in mean blood lactate concentration between the first- and final-round matches was not significant ( P > 0.05). Blood lactate concentration was significantly higher ( P ? 0.04) in matches of long duration than in those of short duration. The mean general rating of perceived exertion for all matches was 13.8 according to the scale used. Most of the wrestlers (53.3%) perceived exertion to be highest in the flexors of the forearm, followed by the deltoids (17.4%) and the biceps brachii muscles (12.0%). In addition to a relatively high rating of perceived exertion in the arm muscles, this indicates a high specific load on the flexor muscles of the forearm.     

Work socialization through part-time work: cultivating self-efficacy and engagement through care

This study provides insight into how work socialization occurs through part-time work in a Youth Employment Program. Drawing on in-depth interviews with youth employees and supervisors, we consider how the young people’s meanings of work were shaped through their early employment experiences. Participants report significant transformations in both their views of work – from seeing it primarily in terms of extrinsic rewards like a paycheck to developing more robust interpretations of work – and their level of self-efficacy. We argue that the organizational culture and supervisor relationships were crucial for the positive outcomes the youth experienced. This study demonstrates the formative impact that part-time work has on young people and the promise of studying work socialization in part-time work. Practically, our findings point to the importance of approaching the employment of young people as more than just an economic exchange. We suggest that those who employ young people should provide a work context marked by routine, supportive interactions with supervisors who provide and uphold clear expectations.     

Evaluation and Opportunities in Overtraining Approaches

Overtraining (OT) as a sports phenomenon can be caused by stressors on various levels (physical, emotional, psychological, and social) and evokes responses on these levels. This study evaluated research and new opportunities in the field of OT by introducing an integrated multidisciplinary approach, based on the single and multistressors approach. The single stressor approach focuses on the training load-recovery imbalance, which results in a stagnating performance, excluding the etiology by nonsport-related factors. The multistressors approach includes all factors as relevant in the etiology of a stagnating performance. In future studies on OT, an integrative approach should not only highlight changes in training regimes and specific responses to training stressors but also focus on the role of training-related recovery, the impact of stressors, and personality factors influencing stress appraisal. This will provide a better insight into the etiology and consequences of OT, necessary for prevention and treatment in sport practice, and enhance the focus on adequate recovery (good sleep, sufficient rest periods) and athletes' stress-related responses.     

The effects of vibration on explosive and reactive strength when applying individualized vibration frequencies

Abstract

The aim of this study was to assess the effects of 8 weeks of whole-body vibrations on explosive and reactive leg strength. Thirty-three physically active students took part in the study and were randomly assigned to an individualized-vibration group, a fixed-vibration group or a control group. The frequency of vibration was set to 30 Hz for the fixed-vibration group, whereas the frequency for the individualized-vibration group was determined by monitoring the participants' EMG_rms activity. The participants in the two vibration groups were exposed three times a week for 8 weeks to a series of 10 × 1-min whole-body vibrations with a 1-min pause between series of vibrations and a 4-min pause after the first five series of vibrations. Jump height in the squat jump increased significantly in all three groups (by 11% for the individualized-vibration group, p = 0.001; by 3% for the fixed-vibration group, p = 0.011; and by 2% for the control group, p = 0.006), but countermovement jump height was not affected. In continuous rebound jumps by the individualized-vibration group, jumping height increased by 22% (p = 0.006) and power increased by 18% (p = 0.002). The results of this study suggest that the use of an individualized vibration frequency produces a greater response from the neuromuscular system and is more beneficial than vibrations at a fixed pre-selected frequency.     

Report to the President on the Use of Technology to Strengthen K–12 Education in the United States: Findings Related to Research and Evaluation

The Panel on Educational Technology was organized in April 1995 under the auspices of the President's Committee of Advisers on Science and Technology (PCAST) to provide advice to the President on matters related to the application of information technologies to K–12 education in the United States. Its findings and recommendations were set forth in March 1997 in the Report to the President on the Use of Technology to Strengthen K–12 Education in the United States. This report was based on a review of the research literature and on written submissions and oral briefings from a number of academic and industrial researchers, practicing educators, software developers, governmental agencies, and professional and industry organizations involved in various ways with the application of technology to education. Its most important finding is that a large-scale program of rigorous, systematic research on education in general and educational technology in particular will ultimately prove necessary to ensure both the efficacy and cost-effectiveness of technology use within our nation's K–12 schools. Finding that less than 0.1 percent of our nation's expenditures for elementary and secondary education are currently invested to determine which educational techniques actually work, and to find ways to improve them—an extremely low level relative to comparable ratios within the private sector—the Panel recommended that this figure be increased over a period of several years to at least 0.5 percent, and sustained at that level on an ongoing basis. Further, because no one state, municipality, or private firm could hope to capture more than a small fraction of the benefits associated with a significant advance in our understanding of how best to educate K–12 students, the Panel concluded that such funding will have to be provided largely at the federal level in order to avoid a systematic underinvestment (attributable to a classical form of economic externality) relative to the level that would be optimal for the nation as a whole. This paper originally appeared as Section 8 of the report.