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1.
The recalibrational theory of human anger predicts positive correlations between aggressive formidability and anger levels in males, and between physical attractiveness and anger levels in females. We tested these predictions by using a three-dimensional body scanner to collect anthropometric data about male aggressive formidability (measures of upper body muscularity and leg–body ratio) and female bodily attractiveness (waist–hip ratio, body mass index, overall body shape femininity, and several other measures). Predictions were partially supported: in males, two of three anger measures correlated significantly positively with several muscularity measures; in females, self-perceived attractiveness correlated significantly positively with two anger measures. However, most of these significant results were observed only after excluding from the sample 27 participants who were older than undergraduate age, leaving a subsample of 40 males and 51 females. Evidence for relationships between anthropometric attractiveness indicators and anger measures was weak, but there was some evidence for relationships between anthropometric attractiveness indicators and self-perceived attractiveness measures. While our results support the recalibrational theory's prediction that anger usage and formidability are positively correlated in males and suggest that this formidability can be assessed via anthropometric measures alone, they also suggest that this prediction may not apply to populations older than undergraduate age. Further, our results suggest that while female anger levels relate positively to self-perceived attractiveness, they are unrelated to most anthropometric measures of bodily attractiveness.  相似文献   

2.
Cricket fast bowlers have a high incidence of serious lumbar injuries, such as lesions in the pars interarticularis. Kinematic studies have shown that bowling actions with large shoulder counter-rotation are associated with significantly higher incidences of lumbar injury. However, in bowling, there has been no calculation of the spinal loads, which are the causal mechanisms of such injuries. In this study, 21 fast bowlers (22.4±3.9 years) of premier grade level and above were tested using a three-dimensional (3D) motion analysis system. The mean ball release speed was 31.9±2.8 m s?1 and ranged from 27.0 to 35.6 m s?1. Kinematics and kinetics were calculated for lumbar spine lateral bending, rotation, and flexion during the delivery and power phases of bowling. Power calculations were used to define the actuation of lumbar spine motion as either active or controlled. The actuation of the lumbar spine was complex, involving multiple sequences of active and controlled motion. In addition, lumbar spine loads were largest during the power phase when the ground reaction forces were highest. In conclusion, the dynamic loads and the cyclical nature of their application when the spine is positioned near its end range of motion may be significant factors of injury to this region. In addition, the lumbar spine in bowling has to vigorously flex, laterally bend and rotate simultaneously in a complex interdependent sequence of actuation patterns. Therefore, any technical change to reduce injury susceptibility needs to consider the mechanics of whole body coordination and timing.  相似文献   

3.
The purpose of this study is to identify physical and performance variables that discriminate elite American junior-aged men weightlifters from nonelite performers. Using a cross-sectional design, multiple discriminant analysis was used to determine field tests identifying elite male junior weightlifters. Young men who were participants (n = 115) at the Junior National and Junior Olympics Weightlifting Championships volunteered as subjects (mean +/- SD age = 14.8 +/- 2.3 years). Elite weightlifters (n = 20) were identified as the top 17.5% of national-level competitors when weightlifting performances were adjusted for body mass using the Sinclair equation. All other weightlifters were classified as nonelite (n = 95). Test batteries were performed immediately upon completion of a national-level weightlifting competition. Variables measured included easily-administered field tests of physical dimensions and body composition, muscular strength and power, flexibility, and gross motor control. The resulting regression equations correctly classified 84.35% of the weightlifters as elite or nonelite. Five variables significantly contributed to the discriminant analysis (Wilks Lambda = 0.6637392, chi(2) = 44.880, df = 5, p < 0.0001, adjusted R(2) = 0.67). Body mass index accounted for 23.13% of the total variance, followed by vertical jump (22.78%), relative fat (18.09%), grip strength (14.43%), and torso angle during an overhead squat (0.92%). The use of these 5 easily administered field tests is potentially useful as a screening tool for elite American junior men weightlifters.  相似文献   

4.
The purpose of this investigation was to examine the changes in performance indicators as they relate to strength and speed-strength development, over 2 years in a group of volleyball players who successfully transitioned from age group (U21) to senior national team in that time period. Sixteen male subjects (age: 18.5 ± 1.5 years, height: 2.00 ± 0.06 m, and weight: 88.4 ± 7.7 kg) participated in this 2-year longitudinal study. During the 24-month period of this investigation, all the subjects gained professional European contracts and also debuted with at least 1 senior national team match. These included, at a minimum, not only international friendly matches but also senior continental championships, World Championships, and the World Cup. Testing included 1 repetition maximum (1RM) and 3RM for the clean and squat, a maximum effort counter movement vertical jump (CMVJ), depth jump from a 0.35-m box (DJ), spike jump (with approach) (SPJ), and lower body speed-strength assessment with a body weight and body weight + 50% load. Large magnitude increases were observed for CMVJ, DJ, and SPJ over the 2-year period (d = 0.80, 0.82, and 0.94, respectively, p < 0.001). Unloaded (body weight) and loaded jump-squat performance also exhibited large improvements for all measured parameters, with very large increases in jump height in the unloaded (d = 1.21, p = 0.002) and loaded jump squat (d = 1.346, p < 0.001). Very large magnitude changes in 1RM Clean and 3RM Squat (d = 1.56 and 2.21, respectively, p < 0.001) were observed over the 2-year investigation period, and a large increase (d = 1.18, p < 0.001) in the lean mass ratio (mass/sum skinfolds). To progress from junior representation to senior national team, volleyball players must increase their CMVJ and SPJ. This is best accomplished through increasing lean mass, reducing fat mass, improving strength and speed strength, and developing high levels of stretch-load tolerance in stretch-shorten cycle activity.  相似文献   

5.
The increased popularity of sports, apart from being beneficial to health, also results in a larger number of injuries, a part of which are also injuries to the stomatognatic system. According to the data from literature orofacial injuries in basketball are frequent, but relatively minor. The World Dental Federation places basketball into the category of medium-risk sports for the occurrence of injuries to the stomatognatic system. The purpose of this investigation was to determine incidence, type and severity of orofacial injuries during basketball and the frequent of the mouthguard use in a selected sample of basketball players from the City of Zagreb and the Zagreb County. The sample consists of 195 athletes who actively participate in basketball, 61 junior and 134 senior players. A total of 2 615 injuries to the stomatognatic system were documented in this research, 529 (20.2%) of those refer to juniors and 2 086 (79.8%) to seniors. The most common injuries are lacerations and contusions of soft tissue 84.4% (21.5% juniors and 78.5% seniors), followed by temporomandibular joint injuries and oral muscles stiffness 13.4% (14.9% juniors and 85.1% seniors) and 2.2% dental injuries (3.5% juniors and 96.5% seniors). Only 6.7% of players (13 players--2 juniors and 11 seniors) have tried to wear a mouthguard, while only one 1% of them (2 players--one junior and one senior) frequently used it. Total number of injuries shows that sports injuries are common during basketball. Average number of almost 4 injuries per player is relatively high. Dental injuries and temporomandibular joint injuries and oral muscles stiffness are relatively rare, only 16%. Lacerations and contusions of soft tissues represent 84% of all injuries and that minor injuries do not require professional care.  相似文献   

6.
C-reactive protein (CRP) is an inflammatory marker, which at low-level elevations is associated with increased cardiovascular risk. Although CRP has been extensively investigated in North American and European settings, few studies have measured CRP among non-Western groups. The present study used dried whole blood spot samples to examine high-sensitivity CRP concentrations among the Yakut (Sakha) of Siberia (85 females, 56 males; 18-58 years old). Our goals were: (1) to compare Yakut CRP concentrations with other populations; (2) to investigate sex differences; and (3) to explore anthropometric correlates of CRP. Results indicate that serum equivalent CRP concentrations are similar to those from industrializing nations, lower than US and European values, and greater than Japanese concentrations. Yakut men and women display similar CRP concentrations; however, CRP was significantly higher among men after adjustment for body fat, age, and smoking. Positive associations were documented between CRP and BMI, body fat, and central adiposity.  相似文献   

7.
8.
This study investigated training loads, injury rates, and physical performance changes associated with a field conditioning program in junior and senior rugby league players. Thirty-six junior (16.9 [95% confidence interval: 16.7-17.1] years) and 41 senior (25.5 [23.6- 27.3] years) rugby league players participated in a 14-week preseason training program that included 2 field training sessions each week. Subjects performed measurements of standard anthropometry (height, body mass, and sum of 7 skinfolds), muscular power (vertical jump), speed (10-, 20-, and 40-m sprint), agility (L run), and maximal aerobic power (multistage fitness test) before and after training. Improvements in agility, muscular power, and maximal aerobic power were observed in both the junior and senior players following training; however, the improvement in maximal aerobic power and muscular power were greatest in the junior players. Training loads and injury rates were higher in the senior players. These findings demonstrate that junior and senior rugby league players adapt differently to a given training stimulus and that training programs should be modified to accommodate differences in training age.  相似文献   

9.
Sperm competition theory predicts that males should modulate sperm investment according to their social status. Sperm speed, one proxy of sperm quality, also influences the outcome of sperm competition because fast sperm cells may fertilize eggs before slow sperm cells. We evaluated whether the social status of males predicted their sperm speed in a wild population of dunnocks (Prunella modularis). In addition to the traditional analysis of the average speed of sperm cells per sample, we also analysed subsamples of the fastest sperm cells per sample. In other words, we systematically evaluated the effects of including different numbers of the fastest sperm in our analyses, ranging from the 5‐fastest sperm cells to the 100‐fastest sperm cells in a sample. We further evaluated whether fitness, defined here as the number of chicks sired per male per breeding season, relates to the sperm speed in the same population. We found that males in monogamous pairings (i.e. low levels of sperm competition), produced the slowest sperm cells, whereas subordinate males in polyandrous male–male coalitions (i.e. high levels of sperm competition) produced the fastest sperm cells. This result was consistent regardless of the number of fastest sperm included in our analyses, but statistical support was conditional on the number of sperm cells included in the analysis. Interestingly, we found no significant relationship between fitness and sperm speed, which suggests that it is possible that the differential mating opportunities across social status levelled out any possible difference. Our study also suggests that it is important to identify biologically meaningful subsets of fastest sperm and cut‐offs for inclusions for assessing sperm competition via sperm speed.  相似文献   

10.
The aims of this study were to determine in elite master swimmers of both genders whether, using anthropometric variables and the hand grip strength measure, it was possible to predict freestyle performance time, whether the considered predictors were related similarly to different events (50, 100, 200, 400, 800 m), and whether they were the same in male and female master swimmers. The relationships between performance times and age, body mass, height, arm length, forearm length, forearm muscle volume, and hand grip strength were examined in 135 elite master swimmers. Pearson's simple correlation coefficients were calculated and then prediction equations were developed. Age, height, and hand grip strength were the best predictors in short-distance events, whereas only age and height were predictors in middle- and long-distance events. The corresponding coefficient of determination (R) of performance times were 0.84 in the 50-m event, 0.73 in the 100-m event, 0.75 in the 200-m event, 0.66 in the 400-m event, and 0.63 in the 800-m event. These regression equations were then cross-validated in a control group of 126 nonelite, age-matched swimmers, obtaining significant and good correlations for all distances (range, r = 0.67 and 0.83; p < 0.01), indicating that predictors are valid in an extended sample of master swimmers. Differences between sexes were not found in 50-m event, but were present in all other events. These models might be useful to determine individual performance times by contributing to improving the individual's training program and the selection of master swimmers. Coaches could have better accuracy in determining whether an athlete needs a strength training program in order to optimize performance time.  相似文献   

11.
This study examined the sleep intra-individual variability (IIV) of rugby league athletes across senior and junior levels during one week of the competitive season. Forty-five rugby league athletes across elite senior, sub-elite senior and elite junior levels each wore actigraphy monitors for seven days during the competitive season, and completed a subjective sleep diary each morning upon waking. Linear mixed models were used to assess differences in sleep measures between playing levels. Intra-individual standard deviations for each sleep measure were calculated for each athlete to determine their respective IIV, allowing differences in IIV between groups to be assessed. Elite junior athletes went to bed later (ES = 0.94 ± 0.50, < 0.05) and woke later than elite senior athletes (ES = 0.94 ± 0.40, < 0.05), while also displaying greater IIV when considering time in bed (ES = 1.14 ± 0.60, < 0.05) and sleep duration (ES = 1.53 ± 0.64, < 0.05) compared with elite senior athletes. Similarly, IIV was more pronounced in elite junior players for time in bed (ES = 0.88 ± 0.60, < 0.05) and sleep duration (ES = 1.03 ± 0.64, < 0.05) compared with sub-elite senior athletes. Despite this, elite junior athletes still obtained sufficient sleep duration, efficiency and quality. The outcomes of this investigation show a distinct difference in the habitual sleep-wake patterns of senior and junior rugby league athletes, and show how sleep IIV differs between playing levels in rugby league.  相似文献   

12.
13.
S P Handa  H K Wolf 《CMAJ》1985,132(1):29-32
Blood pressures were recorded for 8950 students (82.4% of the total student population) of the junior high and high schools of Saint John, NB. Among the boys the mean systolic pressure rose from 104 mm Hg at age 12 to 117 mm Hg at age 18; among the girls the rise was from 105 to 110 mm Hg. The mean diastolic pressure also rose, from 61 to 67 mm Hg, in both sexes. These data are similar to those found in epidemiologic studies in Montreal and Bogalusa, Louisiana. However, the mean systolic values are lower by 10 mm Hg than those in an Edmonton study and the norms published by a United States task force. Recording methods could explain some of the observed differences, but population differences may also contribute. The discrepancies suggest that the current standards for children and adolescents need to be reassessed.  相似文献   

14.
This study investigated the tackling ability of junior elite and subelite rugby league players, and determined the relationship between selected physiological and anthropometric characteristics and tackling ability in these athletes. Twenty-eight junior elite (mean ± SD age, 16.0 ± 0.2 years) and 13 junior subelite (mean ± SD age, 15.9 ± 0.6 years) rugby league players underwent a standardized 1-on-1 tackling drill in a 10-m grid. Video footage was taken from the rear, side, and front of the defending player. Tackling proficiency was assessed using standardized technical criteria. In addition, all players underwent measurements of standard anthropometry (stature, body mass, and sum of 7 skinfolds), acceleration (10-m sprint), change of direction speed (505 test), and lower body muscular power (vertical jump). Junior elite players had significantly greater (p < 0.05) tackling proficiency than junior subelite players (65.7 ± 12.5 vs. 54.3 ± 16.8%). Junior elite players tended to be taller, heavier, leaner, and have greater acceleration, change of direction speed, and muscular power, than the junior subelite players. The strongest individual correlates of tackling ability were acceleration (r = 0.60, p < 0.001) and lower body muscular power (r = 0.38, p < 0.05). When multiple linear regression analysis was performed to determine which of the physiological and anthropometric characteristics predicted tackling ability, fast acceleration was the only variable that contributed significantly (r2 = 0.24, p < 0.01) to the predictive model. These findings demonstrate that fast acceleration, and to a lesser extent, lower body muscular power contribute to effective tackling ability in junior rugby league players. From a practical perspective, strength and conditioning coaches should emphasize the development of acceleration and lower body muscular power qualities to improve tackling ability in junior rugby league players.  相似文献   

15.
As the first recipient of both the Women in Cell Biology Junior and Senior Awards, I look back to identify key components that have provided the foundation for my successful research career. In retrospect, the three most important building blocks have been: identifying and pursing important problems; attracting and mentoring talented postdoctoral fellows and students; and establishing and nurturing strong collaborations.  相似文献   

16.
Journal of Ethology - Metabolic rate correlates with function of the individual, such as foraging patterns and swimming performance. In this study, genetic variation in the routine metabolic rate...  相似文献   

17.
18.
Although strength and conditioning exercises have been prescribed to enhance performance and prevent injury in sailors, little is known about these exercises in comparison to the demands placed on the sailor's musculature while hiking maximally. Because of the difficulty in collecting hiking-related data on water, a 3-minute maximal hiking test (HM180) has been previously developed for use in the laboratory setting. There were 2 aims of this study. The first aim was to determine whether discriminative validity could be shown for the HM180 test in a group of junior sailors of differing ability level and gender. The second aim was to determine whether differences in muscle activation existed between selected strength and conditioning exercises and the HM180 test. Twenty-nine adolescent boy and girl sailors aged between 14 and 16 years from the Singaporean National Byte Class training squad (n = 12) and the Singapore High Participation Group (n = 17) were recruited for this study. The average levels of normalized muscle activation in selected lower limb and trunk muscles in 4 selected strength and conditioning exercises (leg extension, back squat, and back extension exercises, a 30-second hiking hold) and a maximal 3-minute hiking test (the HM180 test) were quantified. Discriminative validity of the HM180 test was shown, and it was confirmed that the strength and conditioning exercises provide an overload stimulus for the HM180 test. Further, similar levels of muscle activation were found for the vastus lateralis in the leg extension and back squat exercises, and the superficial lumbar multifidus in the back extension and back squat exercises. This study has the potential to inform the design of strength and conditioning programs for junior sailors.  相似文献   

19.
Tuning exocytosis for speed: fast and slow modes   总被引:1,自引:0,他引:1  
Exocytic fusion reactions triggered by Ca(2+) are widespread in neural, endocrine, exocrine, hemapoetic and perhaps all cell types. These processes exhibit tremendous variation in latencies to fusion following a Ca(2+) rise and in rates of fusion. We review reported differences for synaptic vesicle (SV) and dense-core vesicle (DCV) exocytosis and attempt to identify key features in the molecular mechanisms of docking, priming and fusion of SVs and DCVs that may account for differences in speed.  相似文献   

20.
The biological mechanisms underlying decline in physical function with age remain unclear. We examined the plasma proteomic profile associated with longitudinal changes in physical function measured by gait speed and grip strength in community‐dwelling adults. We applied an aptamer‐based platform to assay 1154 plasma proteins on 2854 participants (60% women, aged 76 years) in the Cardiovascular Health Study (CHS) in 1992–1993 and 1130 participants (55% women, aged 54 years) in the Framingham Offspring Study (FOS) in 1991–1995. Gait speed and grip strength were measured annually for 7 years in CHS and at cycles 7 (1998–2001) and 8 (2005–2008) in FOS. The associations of individual protein levels (log‐transformed and standardized) with longitudinal changes in gait speed and grip strength in two populations were examined separately by linear mixed‐effects models. Meta‐analyses were implemented using random‐effects models and corrected for multiple testing. We found that plasma levels of 14 and 18 proteins were associated with changes in gait speed and grip strength, respectively (corrected p < 0.05). The proteins most strongly associated with gait speed decline were GDF‐15 (Meta‐analytic p = 1.58 × 10−15), pleiotrophin (1.23 × 10−9), and TIMP‐1 (5.97 × 10−8). For grip strength decline, the strongest associations were for carbonic anhydrase III (1.09 × 10−7), CDON (2.38 × 10−7), and SMOC1 (7.47 × 10−7). Several statistically significant proteins are involved in the inflammatory responses or antagonism of activin by follistatin pathway. These novel proteomic biomarkers and pathways should be further explored as future mechanisms and targets for age‐related functional decline.  相似文献   

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