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Context: Many elite athletes use increased daily training frequencies as a means to increase training load without substantial published literature to support this practice. Purpose: To compare the physiological responses to twice- and once-daily training sessions with similar training volumes. Methods: Ten nationally competitive male weightlifters (age 20.5 ± 1.2 y, body mass 92.9 ± 23.6 kg, training history 5.5 ± 1.5 y) were matched on body mass and training experience, then randomly assigned to train either once or twice daily for 3 wk. Isometric knee-extension strength (ISO), muscle cross-sectional area, vertical-jump peak power, resting hormone concentrations, neuromuscular activation (EMG), and weightlifting performance were obtained before and after the experimental training period. Results: All dependent measures before the training intervention were similar for both groups. A 2-way repeated-measures ANOVA did not reveal any significant main effects (group or trial) or interaction effects (group x trial) for any of the dependent variables. There were also no significant group differences when parameters were expressed as percentage change, but the twice-daily training group had a greater percentage change in ISO (+5.1% vs +3.2%), EMG (+20.3% vs +9.1%), testosterone (+ 10.5% vs +6.4%), and testosterone:cortisol ratio (-10.5% vs +1.3%) than did the once-daily training group. Conclusions: There were no additional benefits from increased daily training frequency in national-level male weightlifters, but the increase in ISO and EMG activity for the twice-daily group might provide some rationale for dividing training load in an attempt to reduce the risk of overtraining. [ABSTRACT FROM AUTHOR]

Body Mass Index (BMI), as an adiposity indicator, assumes that for any given height a change in weight is attributed to a change in fat. This seems problematic in growing youth as great divergence is evident in bone, muscle, and adipose tissue development. Secondly, use of reference populations in categorizing children based on BMI, frequently use arbitrary percentile cut-offs for obesity and do not meet all of the assumptions that cut-offs imply. Lastly, BMI does not control for maturation status. Criterion-referenced assessments of child obesity that account for abdominal adiposity and permit international comparisons, such as waist-to-height ratio (WtHR), must be considered. Better predictive utility has been demonstrated when using WtHR for abdominal adiposity and cardiovascular risk factors in youth compared with BMI. Although multiple methods for assessing waist circumference may be problematic for comparison purposes, its simplicity and international comparability aspects make it a promising alternative to BMI. [ABSTRACT FROM PUBLISHER]

The article discusses research conducted to analyze the top three successful snatch attempts by individual lifters in each weight class at a U.S. National Championship weightlifting meet. After evaluating the lifting techniques of several lifters researchers found that the rearward displacement technique in the drop-under phase in the snatch is not detrimental to performance and actually seems to be a preferred technique in U.S. national level lifters, even in international competitions.

Crossland, BW, Hartman, JE, Lon Kilgore, J, Hartman, MJ, and Kaus, JM. Upper-body anthropometric and strength measures and their relationship to start time in elite luge athletes. J Strength Cond Res 25(10): 2639-2644, 2011-Start time has been shown to be a significant predictor of overall performance in the sport of luge. The starting motion in luge has been described as an explosive upper-body movement that requires significant technique and skill to perfect. This study aims to investigate upper-body factors that may relate to start time in luge. Twenty-two subjects participated in the study as part of their normal off-season training. Each subject had a minimum of 3 years' experience in the sport of luge, and at the time was a member of a U.S. Luge National Team. Subjects completed a 1 repetition maximum (1RM) in the bench press (BP), prone row (PR), and weighted pull-up (WP). Anthropometric distances were taken measuring finger-tip span (FS), biacromial breadth (BB), acromio-radial length, acromio-olecranon length (AO), hand length, and sitting cervical height. Subjects were divided into 2 groups based on which U.S. Luge National team they were currently a member of, Senior National (SN, n = 13) and Junior National (JN, n = 9). A Pearson product-moment correlation coefficient showed several significant (p <= 0.05) relationships between upper-body variables and start time among the groups. The BP and PR 1RM were shown to have a significant relationship in both groups. Among the anthropometric variables, AO was also significant in both groups. The WP, FS, BB, and height were all shown to have a significant relationship with start time in the SN group, but not in the JN group. These results suggest that as luge athletes become more efficient in the starting technique, outside factors such as upper-body strength and anthropometric measures play a larger role in performance. [ABSTRACT FROM AUTHOR]

The article presents a study which found upper-body anthropometric and strength measures have a significant role in performance as elite luge athletes become more efficient in their starting techniques. The participants were members of a U.S. Luge National Team. Research measures were bench press, prone row, weighted pull-up, finger-tip span, biacromial breadth, acromio-radial length, acromio-olecranon length, sitting vertical height, and hand length.

The article presents the results of a study which investigated a method for precisely determining a subject's ventilatory threshold. An overview of related previous research is provided, along with details of the experimental protocol and the mathematical reasoning involved. The study found that quadratic regression analysis of the ventilatory equivalents of carbon dioxide and oxygen resulted in accurate identification of the ventilatory threshold.

The article presents the study conducted regarding the impact of the 11-week training program on the force-time curve characteristics and hormonal alterations of the elite women weightlifters. The study aims to determine the effects of the core and supplemental exercise of the players, as well as the changes on the ration between their testosterone and cortisol. The result shows that alterations of the training volume load can lead to concomitant changes.

Six elite women weightlifters were tested to evaluate force-time curve characteristics and intercorrelations of isometric and dynamic muscle actions. Subjects performed isometric and dynamic mid-thigh clean pulls at 30% of maximal isometric peak force and 100 kg from a standardized position on a 61.0 X 121.9 cm AMTI forceplate. Isometric peak force showed strong correlations to the athletes' competitive snatch, clean and jerk, and combined total (r = 0.93, 0.64, and 0.80 respectively). Isometric rate of force development showed moderate to strong relationships to the athletes' competitive snatch, clean and jerk, and combined total (r = 0.79, 0.69, and 0.80 respectively). The results of this study suggest that the ability to perform maximal snatch and clean and jerks shows some structural and functional foundation with the ability to generate high forces rapidly in elite women weightlifters. [ABSTRACT FROM AUTHOR]

Hypoxia and altered hemodynamic status, both components of myocardial infarction, have been shown to be potent inducers of the 70 kD family of heat shock proteins (HSP70). We hypothesized that after infarction, the surviving myocardium would synthesize HSP70 proteins in a temporally and regionally distinct pattern. We believed that there would be a lack of an HSP70 response in the infarcted area (I), reflecting the loss of viable cells. We further postulated that tissues bordering infarctions (M) would have a compromised HSP70 response. Conversely, we proposed that HSP70 would be induced in septal tissues (S) of the infarcted heart, as a hypertrophic adaptation. A rat model of myocardial infarction was used to examine the changes in relative concentration and distribution of three major HSP70 family proteins; cytoplasmic HSP72, mitochondrial HSP75, and endoplasmic reticular GRP78 (glucose regulated protein) during 21 days of recovery. While all three HSP70 family proteins investigated were detected in all hearts from all groups at all time periods, experimental treatment (infarction) induced changes in relative protein concentrations that varied with time and sample site location. Relative concentrations of HSP72 and GRP78 were unchanged in the 24 h following infarction while relative HSP75 concentrations were halved in M tissues during the same time period. Between days 5 and 7, several changes were noted. M samples displayed nearly twice the relative concentrations of HSP75 and GRP78 after infarction, but showed no change in HSP72. S tissues showed two-fold or larger increases in all three HSP70 family proteins. I samples showed unanticipated increases in HSP75 and GRP78 during this time period. After 14 to 21 days of recovery, HSP70 family protein concentration levels in M, S, and I tissues from infarcted hearts had returned to levels similar to those seen in control animals. We conclude that the myocardium is unable to, or does not, mount an immediate HSP70 response after infarction but does recover such activity by 5-7 days after infarction. [ABSTRACT FROM AUTHOR]

Describes the reaction of organisms to various external stressors. Detection of heat shock response; Role of heat shock proteins in the adaptation to exercise and training; Presence of ATP-binding proteins in the organisms.

Employment, social, and economic factors have the potential to affect the magnitude of an influenza pandemic among farmworkers. Prevention efforts targeted toward livestock farmworkers, including increased access to seasonal influenza vaccine, risk reduction training, various forms of personal protection, and workplace sanitation, are needed. Crop and livestock farmworkers are at increased risk of exposure to influenza A viruses because of limited resources, substandard housing, immigration status, communication and cultural barriers, and discrimination. Recommendations were gathered from migrant clinicians, farmworker advocates, state and federal government agencies, industry stakeholders, and researchers to overcome these barriers, including surveillance of livestock farmworkers, inclusion of farmworker service organizations in planning efforts, and separation of immigration enforcement from emergency assistance. [ABSTRACT FROM AUTHOR]