Optimal Training Length Research Articles

The influence of vibration training in combination with general magnetotherapy on dynamics of performance efficiency in athletes

The objective of this study was to evaluate effects of a combined treatment including vibrostimulation and magnetotherapy on the working capacity of athletes. Participants of the study were 8 male judo wrestlers. It was shown that implementation of a specialized training program comprising seances of vibration loading and general magnetotherapy 40 and 60 min in duration respectively during 3 consecutive days produced marked beneficial effect on the hormonal status of the athletes. Specifically, the three-day long treatment resulted in a significant increase of blood cortisol and testosterone levels considered to be an objective sign of improved performance parameters in athletes engaged in strength and speed sports. The optimal length of vibration training during 3 days of specialized training is estimated at 20 to 40 minutes supplemented by general magnetotherapy for 60 minutes.

Serious Injuries Related to the Segway® Personal Transporter: A Case Series

We describe a case series of emergency department (ED) visits for injuries related to the Segway® personal transporter. This was a retrospective case review using a free-text search feature of an electronic ED medical record to identify patients arriving April 2005 through November 2008. Data were hand extracted from the record, and further information on admitted patients was obtained from the hospital trauma registry. Forty-one cases were included. The median age was 50 years, and 30 patients (73.2%) were women. Twenty-nine (70.7%) of the patients resided outside the District of Columbia, Maryland, and Virginia, and 32 (78.1%) arrived between June and September. Seven (17.1%) patients had documented helmet use. Ten (24.4%) were admitted. Four patients (40% of admitted patients) required admission to the ICU. The severity of trauma in this case series of patients injured by the use of the self-balancing personal transporter is significant. Further investigation into the risks of use, as well as the optimal length and type of training or practice, is warranted. A distinct E-code and Consumer Product Safety Commission's product code is needed to enable further investigation of injury risks for this mode of transportation.

Capacity lower bound and energy efficiency of training‐based MIMO systems over correlated channels

AbstractThe behavior of training‐based multiple‐input multiple‐output wireless communications over correlated channels is studied in the low signal‐to‐noise ratio (SNR) regime from an energy efficiency perspective. To start with, a relaxed but analytically more tractable capacity lower bound is derived where the impacts of channel spatial correlation are considered simply through the ranks of correlation matrices. It shows that, different from the independent and identically distributed case, the optimal training length no longer equals the number of transmit antennas but is just the same as the rank of transmit correlation matrix. Next, the bit energy requirements are analyzed based on the derived capacity lower bound. It shows that the minimum bit energy required for reliable communication is achieved at a nonzero SNR value below, which the bit energy grows to infinity with a zero‐approaching wideband slope. Flash training and transmission scheme is also studied and shown to improve the energy efficiency. In addition, the impacts of spatial correlation, channel coherence interval and antenna number on the energy efficiency are analyzed. It shows that stronger spatial correlation leads to less bit energy, i.e. higher‐energy efficiency. The minimum bit energy is achieved at lower SNR in a more correlated channel. Spatial correlation also helps to reduce the signal peakiness in the flash scheme. And larger coherence interval always improves energy efficiency at all SNR. Finally, the validity of the proposed results is verified by numerical simulations. Copyright © 2009 John Wiley & Sons, Ltd.

Design Guidelines for Training-Based MIMO Systems With Feedback

In this paper, we study the optimal training and data transmission strategies for block fading multiple-input multiple-output (MIMO) systems with feedback. We consider both the channel gain feedback (CGF) system and the channel covariance feedback (CCF) system. Using an accurate capacity lower bound as a figure of merit that takes channel estimation errors into account, we investigate the optimization problems on the temporal power allocation to training and data transmission as well as the training length. For CGF systems without feedback delay, we prove that the optimal solutions coincide with those for nonfeedback systems. Moreover, we show that these solutions stay nearly optimal even in the presence of feedback delay. This finding is important for practical MIMO training design. For CCF systems, the optimal training length can be less than the number of transmit antennas, which is verified through numerical analysis. Taking this fact into account, we propose a simple yet near optimal transmission strategy for CCF systems, and derive the optimal temporal power allocation over pilot and data transmission.

Internal Medicine Resident Perceptions of Optimal Training Duration

To describe internal medicine residents' opinions regarding the optimal duration of internal medicine residency training, and to assess whether these opinions are associated with specific career interests. A national cohort study was conducted during the 2005 Internal Medicine In-Training Examination (IM-ITE), which involved 382 of 388 (98.5%) U.S. internal medicine programs. A sample of 14,579 residents enrolled in three-year categorical or primary care training programs in the United States reported their opinions regarding optimal residency training duration on the IM-ITE 2005 Residents Questionnaire. Reported optimal training duration was assessed by postgraduate training year, sex, medical school location, program type, and reported career plan. Among the residents surveyed, 78.1% reported a three-year optimal length of internal medicine residency training, 15.3% preferred a two-year training duration, and 6.7% preferred a four-year duration. Residents planning careers in general medicine, hospital medicine, and subspecialty fields all preferred a three-year training duration (83.8%, 82.6%, and 75.9%, respectively). Residents planning subspecialty careers were more likely than those planning general or hospital medicine careers to prefer a two-year program (18.7% versus 7.4% and 8.3%). Residents planning generalist or hospitalist careers were more likely to favor a four-year program (8.9% and 9.1%, respectively) compared with residents planning subspecialty careers (5.4%). Most internal medicine residents endorse a three-year optimal duration of internal medicine residency training. This perspective should be considered in further national discussions regarding the optimal duration of internal medicine training.

Capacity Bound of MIMO Systems with MPSK Modulation and Time-Multiplexed Pilots

In this letter, we elucidate the ergodic capacity of multiple-input multiple-output (MIMO) systems with M-ary phase-shift keying (MPSK) modulation and time-multiplexed pilots in frequency-flat Rayleigh fading environment. With linear minimum mean square error (LMMSE) channel estimation, the optimal pilots design is presented. For mathematical tractability, we derive an easy-computing closed-form lower bound of the channel capacity. Based on the lower bound, the optimal power allocation between the data and pilots is also presented in closed-form, and the optimal training length is investigated by numerical optimization. It is shown that the transmit scheme with equal training and data power and optimized training length provides suboptimal performance, and the transmit scheme with optimized training length and training power is optimal. With the latter scheme, in most situations, the optimal training length equals the number of the transmit antennas and the corresponding optimal power allocation can be easily computed with the proposed formula.

Rehabilitation of COPD patients: which training modality

Non pharmacological therapy has been gaining more interest and has been evolving rapidly over the last decade as an essential part of therapy for COPD patients. Pulmonary Rehabilitation (PR), the most important non pharmacological treatment in patients with COPD, has a primary goal: to achieve the highest possible level of individual exercise tolerance, thus reducing the primary and/or secondary health care utilisation. The aim of the present review is to focus the role of exercise training in these patients as well as to address the question on which training methods are the most beneficial. We have therefore undertaken a MEDLINE-based search including the terms: pulmonary rehabilitation, exercise, lung disease/obstructive. Several strategies based on endurance or strength training are nowadays implemented during PR programmes in order to maximise the benefits for each patient. The impaired function of ambulation muscles causing breathlessness as one of the more frequent symptoms in many COPD, suggests that training the lower extremities is the most important goal to achieve during pulmonary rehabilitation of these patients. On the other hand, as muscle strength appears to be an independent contributor to survival and utilisation of health care resources, it seems largely justified also to include this further modality in the PR program of these patients. In conclusion, both modalities are effective and useful for COPD patients. However, whether resistance training should be administered to all COPD and which is the optimal length of strength training still needs to be elucidated.

Estimation of continuous flat fading MIMO channels

Multiple-input-multiple-output (MIMO) systems can provide high data rate wireless services in a rich scattering environment. We study one of the proposals for MIMO systems, the Bell Labs Layered Space-Time (BLAST) architecture. Channel estimation using training sequences is required for coherent detection in BLAST. We apply the maximum-likelihood channel estimator and the optimal training sequences for block flat fading channels to continuous flat fading channels and analyze the estimation error. The optimal training length and training interval that maximize the throughput for a given target bit error-rate are found by computer simulations as functions of the Doppler frequency and the number of antennas.

The training of paraprofessionals as behavior modifiers: a review.

Paraprofessionals are increasingly being employed in the mental health field. While much interest has focused on their roles and functioning, little systematic attention has been devoted to an examination of training practices. Because a particularly compatible relationship may exist between paraprofessionals and the behavioral model of intervention, this review focuses on the training and use of paraprofessionals as behavior modifiers. Paraprofessional populations reviewed include psychiatric aides and nurses, college students, inpatients, and community and indigenous workers. The review concludes that a strong case can be made for the administrative feasibility of training and utilizing diverse groups of paraprofessionals as behavior modifiers. The lack of consistent, solid outcome evidence prohibits a conclusion relative to the effectiveness of these paraprofessionals at this point in time. Numerous researchable questions concerning the effectiveness of various forms of training with paraprofessionals, optimal length of training for various purposes, training resistances, etc., are unanswered. Beyond this, a serious lack of communication of the basic process of training is revealed, and the perhpas questionable roles paraprofessionals are being trained for is discussed.