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At least 19 recordsLinked to original sources
PubMed2026

Impact of Annual School Fitness Reports on Students' Cardiorespiratory Fitness: A Cluster-Randomized Controlled Trial of Parental Reporting.

BACKGROUND: School-based physical fitness testing is an important population health monitoring tool and has the potential to improve student fitness performance. However, few studies exist on the impact of reporting student fitness to parents. METHODS: Using data from the Fit Study (2014-2017) from 12 California public schools, we used mixed-effects models to compare changes in cardiorespiratory fitness (estimated peak oxygen consumption, calculated from the 1-mile run) and strength (curl-ups and push-ups) over 1 and 2 years between students randomized to having their parents receive an annual fitness report (intervention, n = 1638 students) and control (n = 2070) in grades 5 to 8 (ages 10-15 y). The student sample was 47.9% female, 55.9% Hispanic, and 24.1% Asian. RESULTS: After 1 year, intervention students did not demonstrate differential change compared with control students in estimated peak oxygen consumption (between-group change: -0.03 mL/kg/min; 95% CI, -.367 to 0.302), curl-ups (between-group change: 1.2 curl-ups; 95% CI, -0.306 to 2.660), or push-ups (between-group change: 0.1 push-ups; 95% CI, -0.672 to 0.787). Similarly, no differences were seen after 2 years. CONCLUSION: Sending a 2-page, once-a-year school-based fitness report home to parents-in the absence of environmental changes and/or behavioral coaching and support-does not impact student fitness performance after either 1 or 2 years of reporting.

fitness reporting↗
PubMed1977

Fitness effects of EMS-induced mutations on the X chromosome of Drosophila melanogaster. I. Viability effects and heterozygous fitness effects.

Drosophila melanogaster X chromosomes were mutagenized by feeding males sucrose solutions containing ethyl methanesulfonate (EMS); the concentrations of EMS in the food were 2.5 mM, 5.0 mM, and 10.0 mM. Chromosomes were exposed to the mutagen up to three times by treating males in succeeding generations. After treatment, the effective exposures were 2.5, 5.0, 7.5, 10.0, 15.0, and 30.0 mM EMS. X chromosomes treated in this manner were tested for effects on fitness in both hemizygous and heterozygous conditions, and for effects on viability in hemizygous and homozygous conditions. In addition, untreated X chromosomes were available for study. The viability and heterozygous fitness effects are presented in this paper, and the hemizygous fitness effects are discussed in the accompanying one (MITCHELL and SIMMONS 1977). Hemizygous and homozygous viability effects were measured by segregation tests in vial cultures. For hemizygous males, viability was reduced 0.5 percent per mM EMS treatment; for homozygous females, it was reduced 0.7% per mM treatment. The decline in viability appeared to be a linear function of EMS dose. The viabilities of males and females were strongly correlated. Heterozygous fitness effects were measured by monitoring changes in the frequencies of treated and untreated X chromosomes in discrete generation populations which, through the use of an X-Y translocation, maintained them only in heterozygous condition. Flies that were heterozygous for a treated chromosome were found to be 0.4% less fit per mM EMS than flies heterozygous for an untreated one.

Animals↗
PubMed1977

Fitness effects of EMS-induced mutations on the X chromosome of Drosophila melanogaster. II. Hemizygous fitness effects.

X chromosomes mutagenized with EMS were tested for their effects on the fitness of hemizygous carriers. The tests were carried out in populations in which treated and untreated X chromosomes segregated from matings between males and attached-X females; the populations were maintained for several generations, during which time changes in the frequencies of the treated and untreated chromosomes were observed. From the rates at which the frequencies changed, the fitness effects of the treated chromosomes were determined. It was found that flies hemizygous for a mutagenized chromosome were 1.7% less fit per mM EMS treatment than those hemizygous for an untreated chromosome. Since the same flies were only 0.5% per mM less viable than their untreated counterparts, the total fitness effect of an X chromosome carrying EMS-induced mutants is three to four times greater than its viability effect. By comparing the heterozygous effect of a mutagenized X chromosome on fitness with the corresponding hemizygous effect, the dominance value for the chromosome is estimated to be about 0.25.

Animals↗
PubMed1979

The effect of a four-month physical fitness program on a young and an old group matched for physical fitness.

A young (X = 36.8 years) and an old (X = 52.9 years) group (n = 12) matched for physical fitness performed a graded exercise test at the beginning and after a 4-month physical fitness program consisting of calisthenics, jogging, and recreational activities. The purpose of the study was to determine if there were any differences in response to physical training in the two age groups of similar fitness. Sixteen physiological and four biochemical variables were measured. There was no significant difference in VO2 max between the young and old groups. Also, there were no significant differences between groups for serum total lipids, cholesterol, triglycerides, or glucose levels. The effects of the training program were similar for both the young and old groups.

Adult↗
PubMed1978

Overexertion injuries in keep-fit athletes. A study on overexertion injuries among non-competitive keep-fit athletes.

During three years, 274 exertion injuries in middle-aged keep-fit athletes were collected. A keep-fit athlete was a person, who regularly took part in noncompetitive sports activities. Exertion injury was a nontraumatic pain syndrome in the musculo-skeletal system. In the material, there were 35 women and 239 men. Most of them were 30--39 years old. Most exertion injuries took place in July, August, and September. About 80% of the patients were joggers. 80% of them had been training regularly for more than one year. At the moment of occurence of the symptoms, 68% of the patients trained 3--5 times a week. Joggers ran approx. 40 km/week. About 30% of the injuries took place in the knee, 24% in the ankle, heel and foot, 17% in the leg, and 9% in the achilles tendon. Almost one fifth of the pain syndromes were chronic in nature. The majority responded well to rest and to conservative treatment. Fifteen cases were treated surgically. Most of the exertion injuries were typical exertion syndromes seen also in competitive athletes. Others were degenerative changes, organic anomalies etc., which revealed their first symptoms during regular keep-fit activities.

Adolescent↗
PubMed1978

Genetic and evolutionary fitness.

The advantages and disadvantages of evolutionary fitness (probability that a single mutant line will not become extinct) and genetic fitness (mean fecundity) are compared. For deterministic processes the two are equivalent, but for stochastic branching processes they may be totally unrelated except that an absolute genetic fitness of unity or less implies an evolutionary fitness of zero. To know the variance as well as the mean family size does not in general uniquely determine the evolutionary fitness. Except where genetic fitness is close to unity, the impact of selection is shown to be rapid for the binomial, Poisson, negative binomial, and truncated negative binomial distributions. Evolutionary fitness, though somewhat cumbersome, has greater relevance to evolution, genetic counseling, and voluntary population control; but genetic fitness which is much easier to handle is the more appropriate measure where a large number of mutants is involved. Some empirical data on the transmission of various types of characters from parent to child are analyzed to allow comparison of genetic fitness, Crow's index, and a Malthusian parameter, with evolutionary fitness. There is a fair, but far from perfect, agreement among them. Multiple correlation of evolutionary fitness with mean and variance of family size taken jointly suggests a much more satisfactory approximation. It thus appears that, at the least, the population geneticist cannot afford to ignore the variance (which is not adequately represented in Crow's index). These relationships, based on two sets of data only may be accidental and should be invoked with caution. It seems more than likely that other aspects of the distribution of family size (eg, even higher moments) may contain relevant information in certain cases.

Biological Evolution↗
PubMed1978

Proper fitting of the cervical orthosis.

This study evaluated the effect of fitting of the sternal occipital mandibular immobilization (SOMI) orthosis in restricting sagittal cervical spine motion. Cervical orthotic devices are usually fitted according to the subjective tolerance of the patient. Pressures were recorded after fitting in the usual manner by a certified orthotis and when fitted more loosely. Eight able-bodied adults were fitted in this manner and were then immobilized in a straight-backed chair while lateral cervical spine films were taken in neutral, flexion, and extension. Previously standardized methods were used to measure flexion-extension of the cervical spine. The resting pressures, when fitted in the usual manner, were approximately 105 mmHg at the chin and occiput. When pressure sensors were used to fit the brace loosely, the average pressure was approximately 25 mmHg. The data indicate that regardless of fit, there was no significant difference in the mobility of the entire cervical spine or at any intervertebral level. Recommendations for fitting of the SOMI are discussed.

Cervical Vertebrae↗
PubMed2026

Competing subclones and fitness diversity shape tumor evolution across cancer types.

MOTIVATION: Intratumor heterogeneity arises from ongoing somatic evolution and complicates cancer diagnosis, prognosis, and treatment. Reconstructing evolutionary dynamics typically requires spatiotemporal samples, which are often unavailable in clinical settings. Computational approaches that can infer tumor evolutionary history from single-timepoint bulk sequencing data remain limited. RESULTS: We present estimating evolutionary events through single-timepoint sequencing (TEATIME), a novel computational framework that models tumors as mixtures of two competing cell populations: an ancestral clone with baseline fitness and a derived subclone with elevated fitness. Using cross-sectional bulk sequencing data, TEATIME estimates mutation rates, timing of subclone emergence, relative fitness, and number of generations of growth. To quantify intratumor fitness asymmetries, we introduce a novel metric-fitness diversity-which captures the imbalance between competing cell populations and serves as a measure of functional intratumor heterogeneity. Applying TEATIME to 33 tumor types from The Cancer Genome Atlas, we revealed divergent as well as convergent evolutionary patterns. Notably, we found that immune-hot microenvironments constraint subclonal expansion and limit fitness diversity. Moreover, we detected temporal dependencies in mutation acquisition, where early driver mutations in ancestral clones epistatically shape the fitness landscape, predisposing specific subclones to selective advantages. These findings underscore the importance of intratumor competition and tumor-microenvironment interactions in shaping evolutionary trajectories, driving intratumor heterogeneity. Lastly, we demonstrate that TEATIME-derived evolutionary parameters and fitness diversity offer novel prognostic insights across multiple cancer types. AVAILABILITY AND IMPLEMENTATION: R implementation of TEATIME is available on GitHub (https://github.com/liliulab/TEATIME) and Zenodo (https://zenodo.org/records/17422174).

Neoplasms↗
PubMed1979

Strength and fitness and subsequent back injuries in firefighters.

This prospective investigation was done to evaluate five strength and fitness measurements and the subsequent occurrence of back injuries in 1652 firefighters for the years 1971 to 1974. The prospective measurements included flexibility, isometric lifting strength, bicycle ergometer exercise measurements of two-minute recovery heart rate, diastolic blood pressure at a heart rate of 160 beats per minute and watts of effort required to sustain heart rate at 160. Three fitness and conditioning groups were established by multivariate ranking and regression techniques (259 high, 266 low, and 1127 middle) and the subsequent back injuries were tabulated for the three groups. The results showed a graded and statistically significant protective effect for added levels of fitness and conditioning (least fit, 7.1% injured; middle fit, 3.2% jured; and most fit, 0.8% injured). It was concluded that physical fitness and conditioning of firefighters are preventive of back injuries and that further investigations are warranted to study other injuries and physical fitness in this physically active occupational group.

Adult↗
PubMed2026

Synonymous mutations in essential genes infrequently produce fitness effects in human cell lines.

The assumption that synonymous mutations are fitness-neutral is central to many foundational results in the fields of genetics, genomics, evolutionary biology, and medicine. However, recent results suggest synonymous mutations have pervasive and strong fitness effects. These vigorously debated studies in non-human model systems have even suggested that the proportion of synonymous mutations and their fitness effect sizes are similar to non-synonymous mutations. To probe the fitness effect of synonymous mutations, we utilized recent advances in base editing to test 8558 potential synonymous mutations in 128 highly essential genes in human cell lines. Importantly, our library design excluded splice-proximal sites, ensuring a direct test of codon-level synonymous effects independent of splicing disruption. We find that synonymous mutations rarely have fitness effects on growth, occurring around 37.9-fold (95% CI: 22.16-81.48-fold) less frequently than missense mutations. In this experimental context, these findings demonstrate that synonymous mutations impact cellular fitness far less frequently than missense mutations. These results deviate from earlier reports of widespread synonymous fitness effects in yeast, yet they align with recent prime editing data observed in other human cell lines.

Humans↗
PubMed1976

Exercise fitness, cardiac work and blood viscosity factors in patients and normals.

A study of 41 cardiovascular patients and normals showed significant correlations between physical fitness (as expressed by a fitness index based on work output) and high shear rate blood viscosity (p less than 0.01); between the cardiac work expressed as double product (= myocardial oxygen demand) and aggregation of red cells (p less than 0.05); between the triple term of cardiac work (fitness index divided by double product) and high shear rate blood viscosity (p less than 0.005) or aggregation of red cells (p less than 0.05), in all cases correlations being negative i.e., higher cardiac work or higher fitness being related to low blood viscosity or lower aggregation of red cells. Significant differences were found between high-fitness and low-fitness groups, the high-fitness group showing from plasma viscosity (p less than 0.0005), lower fibrinogen level (p less than 0.05), and higher albumin/fibrinogen ratio (p less than 0.01).

Adult↗