Analysis of body measurements of newborn purebred Belgian Blue calves

At calving, purebred animals of the Belgian Blue (BB) breed are compromised by the incompatibility in size and shape of the dam and her calf, resulting in a very high incidence of dystocia problems. To clarify which body parts of the calf are of decisive importance to allow natural delivery and to investigate both the mean value as well as the variation among these body sizes within this breed (variation being an important condition for selection), measurements of nine body parts (body weight at birth (BW), body length (BL), length of the head (LH), shoulder width (SW), hip width (HW), heart girth (HG), withers height (WH) and the circumference of the fetlock of both the front (CFF) and the hind leg (CFH)) were assessed in 147 newborn purebred BB calves on 17 farms. Simple and partial correlations were assessed and we examined whether environmental factors (gender of the calf, parity of the cow, type of calving, season of birth and time of measurement after birth) were significantly associated with these specific calf measurements. The mean BW was 49.2 ± 7.1 kg. The average BL was 56.4 ± 4.5 cm and the mean LH was 24.4 ± 2.3 cm. Measurements obtained for SW and HW were 22.4 ± 2.2 and 22.9 ± 2.1 cm, respectively, whereas the mean WH was 71.1 ± 4.7 cm. Measurements of circumferences revealed a CFF of 17.9 ± 1.1 cm, a CFH of 18.0 ± 1.0 cm and a mean HG of 78.0 ± 5.4 cm. Partial correlations of the BW with eight body measurements were significant (P < 0.01) and ranged between 0.17 and 0.85; 0.42 and 0.88; and 0.24 and 0.88 when corrected for gender, parity and type of calving, respectively. BL (P < 0.01) and the CFF and CFH (P < 0.001) are larger in bull calves than in heifer calves. Calves born through caesarean section had broader SW (P < 0.01) and HW (P < 0.01) when compared with calves born after natural calving (defined as born per vaginam without assistance or with slight traction). Sizes of calves born out of multiparous cows were generally larger than of calves born out of heifers (SW: P < 0.001; HW: P < 0.05). As SW and HW are the broadest points of a BB calf, they are both candidates for being the limiting measures for calving ease, but the difference between HW and SW for the total data set was not different from zero (P > 0.05). In contrast to male calves in which no significant difference (between HW and SW) could be found, female calves show the difference between HW and SW that was significantly different from zero (P < 0.001); thus, in female calves, the HW is the most limiting factor of the calf's body. The significant variation in some body measures between the calves and the strong correlation within these sizes raises the possibility of selection towards smaller calves aiming to limit the dystocia problem in the BB breed. Furthermore, on the basis of our results, we were able to build equations for the farmer to use at the moment of calving containing the LH, the CF and the calf's gender to estimate SW and HW, the limiting body parts of the calf to be born naturally. Together with the knowledge of the pelvic size of the dam, this information gives the obstetrician or the farmer a more accurate prediction of the probability of natural calving at parturition.     

Low-fat diet alters intramuscular substrates and reduces lipolysis and fat oxidation during exercise

We determined whether a low-fat diet reduces intramuscular triglyceride (IMTG) concentration, whole body lipolyis, total fat oxidation, and calculated nonplasma fatty acid (FA) oxidation during exercise. Seven endurance-trained cyclists were studied over a 3-wk period during which time they exercised 2 h/day at 70% of maximum O2 uptake VO(2 max) and consumed approximately 4,400 kcal/day. During the 1st wk, their fat intake provided 32% of energy. During the 2nd and 3rd wk, they were randomly assigned to eat 2 or 22% of energy from fat (2%FAT or 22%FAT). Compared with 22%FAT, 2%FAT lowered IMTG concentration and raised muscle glycogen concentration at rest (P < 0.05). Metabolism was studied during 1 h of exercise at 67% VO(2 max) performed in the fasted state. 2%FAT resulted in a 27% reduction (P < 0.05) in total fat oxidation vs. 22%FAT without altering the stable isotopically determined rates of plasma free fatty acid or glucose disappearance. Therefore, 2%FAT reduced calculated nonplasma FA oxidation by 40% in association with a 19% reduction in whole body lipolysis while increasing calculated minimal muscle glycogen oxidation compared with 22%FAT (all P < 0.05). In summary, an extremely low fat (2% of energy) and high-carbohydrate diet lowers whole body lipolysis, total fat oxidation, and nonplasma FA oxidation during exercise in the fasted state in association with a reduced concentration of intramuscular triglyceride.     

Validity of bioelectric impedance for body composition assessment in children

Whole-body bioelectrical impedance analysis (BIA) was evaluated for its reliability and accuracy in estimating body composition in children. The hypothesis that the index, body height2 divided by resistance (RI), can accurately predict fat-free body mass (FFB) and percent fat (%FAT) in children was tested on 94 caucasian children 10-14 yr old. Criterion variables were FFB and %FAT estimated using multicomponent equations developed for children. BIA measurements (resistance and reactance) were found to be reliable. Prediction accuracy (standard error of the estimate, SEE) for FFB from RI alone was 2.6 kg and for %FAT from RI and body weight was 4.2%. For RI, anthropometric variables and reactance, the SEE improved to 1.9 kg FFB. For RI and anthropometric variables, the SEE was 3.3% FAT. For anthropometric variables alone, the SEE's were 2.1 kg FFB and 3.2% FAT. Adult FFB and %FAT prediction equations cross-validated with this sample resulted in SEE's similar to those for adult samples. We conclude that RI together with anthropometry is a reliable and an acceptably accurate method of estimating FFB mass and %FAT in children.     

An electromyographical comparison of trunk muscle activity during isometric trunk and dynamic strengthening exercises

The purpose of this study was to compare rectus abdominis and erector spinae muscle activity during isometric (prone bridge [PB] and superman [SM]) and dynamic strengthening exercises (back squat, front squat [FS], and military press). Participants (n = 10, age 21.8 ± 2.6 years; body mass 82.65 ± 10.80 kg, 174.5± 7.2 cm), performed each exercise in a randomized order, using a repeated-measures design. Electromyographical (EMG) activity (sampling at 2,000 Hz) of the rectus abdominis (RA) and the erector spinae (ES) muscles was recorded throughout the duration of the exercises. Intraclass correlations demonstrated the highest levels of reliability for muscle activity during the isometric exercises; however, all exercises demonstrated high level of reliability (r = 0.764-0.998, p ≤ 0.01). The PB demonstrated significantly greater (p < 0.01) RA activity compared to all other exercises. The ES activity was significantly (p < 0.01) greater during the FS (1.010 ± 0.308 root mean square value [RMS (V)]) and SM (0.951 ± 0.217 RMS[V]) and compared to all other exercises, although there was no significant difference (p > 0.05) between the FS and the SM exercise. The PB may be the most suitable exercise for strengthening the RA, compared to dynamic exercises at a low to moderate load, because of a higher level of muscle activity. The FS may be a useful alternative to isometric exercises when strengthening the ES, because it results in slightly higher muscle activity levels when using only a light to moderate load. Because of the dynamic nature of the FS, this may also be more beneficial in transferring to activities of daily living and sporting environments.     

Comparison of heart rate and session rating of perceived exertion methods of defining exercise load in cyclists

The aim of this study was to analyze the competition load using the session rating of perceived exertion (RPE) during different professional cycling races and to assess its validity using the competition load based on heart rate (HR). During 2 consecutive seasons, 12 professional cyclists (mean ± SEM: age 25 ± 1 years, height 175 ± 3 cm, body mass 65.9 ± 2.0 kg, and V(O2)max 78.5 ± 1.7 ml · kg(-1) · min(-1)) competed in 5-, 7-, and 21-day cycling races. The HR response and session RPE were measured during the races to calculate the competition load based on the training impulse of the HR (TRIMP(HR)) and RPE data (TRIMP(RPE)). The highest (p < 0.05) TRIMP(RPE) was observed in 21-day races. However, the higher (p < 0.05) TRIMP(HR) was found in 5- and 7-day races. When TRIMP(HR) and TRIMP(RPE) were normalized by competing distance, neither TRIMP(HR) · km(-1) nor TRIMP(RPE) · km(-1) was significantly different between the analyzed cycling races. We found significant (p < 0.001) correlations between TRIMP(HR) and TRIMP(RPE) (r = 0.75) and between TRIMP(HR) · km(-1) and TRIMP(RPE) · km(-1) (r = 0.90). In conclusion, this study showed that the session RPE can be used to quantify the competition load during professional cycling races. This method can be a useful and noninvasive tool for coaches to monitor and control the training load in cyclists.     

Reliability and detecting change following short-term creatine supplementation: comparison of two-component body composition methods

The purpose of the present study was twofold: firstly, to assess the reliability of various body composition methods, and secondly, to determine the ability of the methods to estimate changes in fat-free mass (FFM) following creatine (Cr) supplementation. Fifty-five healthy male athletes (weight 78.3 +/- 10.3 kg, age 21 +/- 1 years) gave informed consent to participate in this study. Subjects' FFM was estimated by hydrostatic weighing (HW), air-displacement plethysmography (ADP), bioelectrical impedance analysis (BIA), near-infrared spectroscopy (NIR), and anthropometric measurements (ANTHRO). Measurements were taken on 2 occasions separated by 7 days to assess the reliability of the methods. Following this, 30 subjects returned to the laboratory for an additional test day following 7 days of Cr supplementation (20 g.d(-1) Cr + 140 g.d(-1) dextrose) to assess each method's ability to detect acute changes in FFM. In terms of reliability, we found excellent test-retest correlations for all 5 methods, ranging from 0.983 to 0.998 (p < 0.001). The mean biases for the 5 methods were close to 0 (range -0.1 to 0.3 kg) and their 95% limits of agreement (LOAs) were within acceptable limits (HW = -1.1 to 1.7 kg; ADP = -1.1 to 1.2 kg; BIA = -1.0 to 1.0 kg; NIR = -1.4 to 1.4 kg); however, the 95% LOAs were slightly wider for ANTHRO (-2.4 to 2.6 kg). Following Cr supplementation there was a significant increase in body mass (from 77.9 +/- 10.1 kg to 78.9 +/- 10.3 kg, p = 0.000). In addition, all 5 body composition techniques detected the change in FFM to a similar degree (mean change: HW = 0.9 +/- 0.6 kg; ADP = 0.9 +/- 0.6 kg; BIA = 0.9 +/- 0.6 kg; NIR = 0.8 +/- 0.5 kg; ANTHRO = 1.0 +/- 0.7 kg; intraclass correlation coefficient = 0.962). We conclude that between-day differences in FFM estimation were within acceptable limits, with the possible exception of ANTHRO. In addition, all 5 methods provided similar measures of FFM change during acute Cr supplementation.     

Muscle activity and time to task failure differ with load compliance and target force for elbow flexor muscles

The primary purpose of this study was to determine the influence of load compliance on time to failure during sustained isometric contractions performed with the elbow flexor muscles at four submaximal target forces. Subjects pulled against a rigid restraint during the force task and maintained a constant elbow angle, while supporting an equivalent inertial load during the position task. Each task was sustained for as long as possible. Twenty-one healthy adults (23 ± 6 yr; 11 men) participated in the study. The maximal voluntary contraction (MVC) force was similar (P = 0.95) before the subjects performed the force and position tasks at each of the four target forces: 20, 30, 45, and 60% of MVC force. The time to task failure was longer for the force tasks (576 ± 80 and 325 ± 70 s) than for the position tasks (299 ± 77 and 168 ± 35 s) at target forces of 20 and 30% (P < 0.001), but was similar for the force tasks (178 ± 35 and 86 ± 14 s) and the position tasks (132 ± 29 and 87 ± 14 s) at target forces of 45 and 60% (P > 0.19). The briefer times to failure for the position task at the lower forces were accompanied by greater rates of increase in elbow flexor muscle activity, mean arterial pressure, heart rate, and rating of perceived exertion. There was no difference in the estimates of external mechanical work at any target force. The dominant mechanisms limiting time to failure of sustained isometric contractions with the elbow flexor muscles appear to change at target forces between 30 and 45% MVC, with load compliance being a significant factor at lower forces only.     

Modified iodine-paper technique for the standardized determination of sweat gland activation

Quantifying sweat gland activation provides important information when explaining differences in sweat rate between populations and physiological conditions. However, no standard technique has been proposed to measure sweat gland activation, while the reliability of sweat gland activation measurements is unknown. We examined the interrater and internal reliability of the modified-iodine paper technique, as well as compared computer-aided analysis to manual counts of sweat gland activation. Iodine-impregnated paper was pressed against the skin of 35 participants in whom sweating was elicited by exercise in the heat or infusion of methylcholine. The number of active glands was subsequently determined by computer-aided analysis. In total, 382 measurements were used to evaluate: 1) agreement between computer analysis and manual counts; 2) the interrater reliability of computer analysis between independent investigators; and 3) the internal reliability of sweat gland activation measurements between duplicate samples. The number of glands identified with computer analysis did not differ from manual counts (68 ± 29 vs. 72 ± 24 glands/cm(2); P = 0.27). These measures were highly correlated (r = 0.77) with a mean bias ± limits of agreement of -4 ± 38 glands/cm(2). When comparing computer analysis measures between investigators, values were highly correlated (r = 0.95; P < 0.001) and the mean bias ± limits of agreement was 4 ± 18 glands/cm(2). Finally, duplicate measures of sweat gland activation were highly correlated (r = 0.88; P < 0.001) with a mean bias ± limits of agreement of 3 ± 29 glands/cm(2). These results favor the use of the modified-iodine paper technique with computer-aided analysis as a standard technique to reliably evaluate the number of active sweat glands.     

A +2138InsCAGACC polymorphism of the melanocortin receptor 3 gene is associated in human with fat level and partitioning in interaction with body corpulence

BACKGROUND: The melanocortin system includes five receptors (MC1R to MC5R), and mouse and human MC4R has been shown to be involved in the regulation of feeding, and mouse MC3R in body composition. To verify a possible similar effect of MC3R in humans, we analyzed one insertion and one single nucleotide polymorphism by restriction fragment length polymorphisms (RFLP), and a microsatellite (D20S32e) in relation to body composition and glucose metabolism. METHODS: Eight hundred twelve subjects of the Québec Family Study (QFS) cohort were analyzed for body composition, food intake, and energy metabolism phenotypes. Southern Blot with the complete MC3R cDNA was used to detect a new +2138InsCAGACC variant by Pst1 restriction. PCR-RFLP with BsaJ1 was used to type amino acid polymorphism V81I arising from a G241A nucleotide change. PCR and automatic DNA sequencers were used for the analysis of the TG dinucleotide repeat D20S32e located between -1933/-1892 of MC3R. In a covariance analysis among genotypes, phenotypes were adjusted for age and sex as covariates. Food intake and energy metabolism phenotypes were also adjusted for body mass index (BMI), and leptin and abdominal fat, as assessed by a computed tomography scan, for fatness using six skinfold thicknesses. RESULTS: An association between the +2138InsCAGACC MC3R polymorphism was observed with fat mass (FM), percent body fat (%FAT), and total abdominal fat (ATF). Homozygote subjects for the +2138 insertion variant allele in normal weight (BMI < 25 kg/m(2)) and overweight (25 < or = BMI < 30 kg/m(2)) subjects showed a similar level of fatness despite the overall difference in BMI. In normal weight, homozygotes for the insertion allele showed higher mean values than heterozygotes and homozygotes for wild-type allele without insertion (%FAT: 24.0 +/- 1.1 versus 19.3 +/- 0.9 and 20.5 +/- 0.8, p = 0.0005; FM: 15.7 +/- 0.9 kg versus 11.7 +/- 0.7 kg and 12.6 +/- 0.6 kg, p = 0.0003). In contrast, overweight subjects homozygote for the variant allele showed lower mean values (%FAT: 27.0 +/- 1.2 versus 31.4 +/- 0.8 and 30.9 +/- 0.7, p = 0.002; FM: 18.3 +/- 1.0 kg versus 22.8 +/- 0.8 kg and 22.0 +/- 0.6 kg, p = 0.0001). This resulted in a similar level of body fat between both BMI groups for subjects homozygote for the insertion allele versus wild-type allele carriers (%FAT: +/-2-3% versus +/-10-12%; FM: +/-2 kg versus +/-9-11 kg). In obese subjects (BMI > or = 30 kg/m(2) ), a lower level of ATF was seen (-15%, p = 0.002). Other polymorphisms and phenotypes tested showed no association. CONCLUSION: A new 12138InsCAGACC MC3R polymorphism is associated with the level of adiposity and with body fat partitioning in interaction with corpulence in humans.     

In vitro primary satellite cell growth and differentiation within litters of pigs

Postnatal muscle growth is dependent on satellite cell (SC) proliferation, differentiation and fusion to increase the DNA content of existing muscle fibres and thereby the capacity to synthesize protein. The purpose of the present study was to examine the ability of isolated SCs from low, medium and high weaning weight litter mates of pigs to proliferate and differentiate, and to affect protein synthesis and degradation after fusion into myotubes. At 6 weeks of age, SCs from the lowest weight (LW), medium weight (MW) and highest weight (HW) female pigs within eight litters were isolated. Thereby, eight cultures of SCs were established for each of the three weight groups within litter, representing three groups of SCs from pigs exhibiting differences in postnatal muscle growth performance. Proliferation was estimated as the number of viable cells at different time points after seeding. SC differentiation was evaluated by measuring the activity of the muscle-specific enzyme, creatine phosphokinase, and protein synthesis and degradation were measured by incorporation and release of 3H-tyrosine, respectively. A tendency towards a difference in proliferation between SC cultures was found (P = 0.09). This was evident as the number of viable cells at day 3 was lower in cultures from LW pigs than from HW (P < 0.05) and MW (P < 0.01) pigs. Differentiation was significantly different between cultures (P < 0.05). There was a significant difference between LW and MW cultures at 72 h (P < 0.05), and a tendency towards a difference between LW and HW cultures at 45 h (P = 0.07). Protein synthesis per μg protein or per μg DNA did not differ among SC cultures from LW, MW and HW pigs. Neither did protein degradation rate differ significantly among SC cultures from LW, MW and HW pigs. Overall, the results show that SCs from LW pigs seem to proliferate and differentiate at a slower rate than SCs from MW and HW pigs. The results found in this study show no difference in the ability of SCs to affect protein synthesis or degradation between SCs from litter mates exhibiting different growth rates in vivo.     

Effect of clothing type on validity of air-displacement plethysmography

The purpose of the study was to evaluate the validity of an air-displacement plethysmography system (AP) within the general population, while wearing (1) a racing-type swimsuit (AP(SS)) and (2) participant's personal undergarments (AP(UG)), against hydrodensitometry (HW). Fifty women and 50 men were measured for body volume, density, and fat percentage by HW and compared with AP(SS) and AP(UG). For women, AP(UG) and AP(SS) were similar, although significant differences (p < 0.001) were observed between AP(UG) and HW and between AP(SS) and HW. For men, there was no significant difference between AP(UG) and HW; however, significant differences (P < or = 0.01) were found between AP(UG) and AP(SS) and between AP(SS) and HW. The small discrepancy in measured values between AP and HW are within the measurement error for the instrumentation and these data support the use of AP for determination of body composition in adults across a wide range of body size (body mass index [BMI] 17.7-35.2 kg.m(-2)) and age (18-57 y). Participants' personal undergarments provide a practical alternative to a spandex swimsuit when measuring body composition by AP in women but not in men.     

Smith machine counterbalance system affects measures of maximal bench press throw performance

Equipment with counterbalance weight systems is commonly used for the assessment of performance in explosive resistance exercise movements, but it is not known if such systems affect performance measures. The purpose of this study was to determine the effect of using a counterbalance weight system on measures of smith machine bench press throw performance. Ten men and 14 women (mean ± SD: age, 25 ± 4 years; height, 173 ± 10 cm; weight, 77.7 ± 18.3 kg) completed maximal smith machine bench press throws under 4 different conditions (2 × 2; counterbalance × load): with or without a counterbalance weight system and using 'light' or 'moderate' net barbell loads. Performance variables (peak force, peak velocity, and peak power) were measured using a linear accelerometer attached to the barbell. The counterbalance weight system resulted in significant (p < 0.001) reductions in measures of peak force (mean difference ± standard error: light: -112 ± 20 N; moderate: -140 ± 23 N), peak velocity (light: -0.49 ± 0.10 m·s; moderate: -0.33 ± 0.07 m·s), and peak power (light: -220 ± 43 W; moderate: -143 ± 28 W) compared with no counterbalance system for both load conditions. Load condition did not affect absolute or percentage reductions from the counterbalance weight system for any variable. In conclusion, the use of a counterbalance weight system reduces accelerometer-based performance measures for the bench press throw exercise at light and moderate loads. This reduction in measures is likely because of an increase in the external resistance during the movement, which results in a discrepancy between the manually input and the actual value for external load. A counterbalance weight system should not be used when measuring performance in explosive resistance exercises with an accelerometer.     

Irregular Heartwood Formation in Maritime Pine (Pinus pinaster Ait):Consequences for Biomechanical and Hydraulic Tree Functioning

As the proportion of sapwood (SW) transformed into heartwood(HW) is irregular both radially and longitudinally in trunksof Maritime pine (Pinus pinaster Ait.), it has been suggestedthat HW formation is a developmental process, regulated internallywithin the tree. In trees where stem growth is eccentric dueto stem lean or wind action, the number of annual growth ringsof SW transformed into HW is greater on the compressed sideof the tree. To determine the contribution to bending stiffness,if any, of this prematurely formed HW, four point bending testswere carried out on fresh HW and SW samples taken from the samegrowth ring, or neighbouring growth rings, at different cross-sectionalpositions at a height of 2 m from six 52-year-old Maritime pines.The mean (±s.e.) modulus of elasticity (E) was 7.6 ±0.3 GPa (longitudinal direction) for all samples. No significantdifferences in E were found between HW and SW; thus HW doesnot play a significant mechanical role in bending stiffness.To test a second hypothesis that early HW formation on the compressedside of trees may maintain a constant, optimal volume of SWaround the tree, the Pipe Model Theory was applied to 12 52-year-oldleaning Maritime pines (angle of lean varied from 0–22°).The surface area (S) of the SW was determined at different heightsup the trunk and correlated with crown surface area (S_crown).Regressions between S_SWandS_crown were highly significant, therebysupporting the theory that HW formation and extension is controlledinternally in Maritime pine. HW formation in Maritime pine thenserves to maintain an optimal proportion of functional SW whichis an important criterion for survival in a species often subjectedto severe drought for long periods. Copyright 2001 Annals ofBotany Company Heartwood, sapwood, bending test, Pipe Model Theory, Pinus pinaster     

Peak power, force, and velocity during jump squats in professional rugby players

Training at the optimal load for peak power output (PPO) has been proposed as a method for enhancing power output, although others argue that the force, velocity, and PPO are of interest across the full range of loads. The aim of this study was to examine the influence of load on PPO, peak barbell velocity (BV), and peak vertical ground reaction force (VGRF) during the jump squat (JS) in a group of professional rugby players. Eleven male professional rugby players (age, 26 ± 3 years; height, 1.83 ± 6.12 m; mass, 97.3 ± 11.6 kg) performed loaded JS at loads of 20-100% of 1 repetition maximum (1RM) JS. A force plate and linear position transducer, with a mechanical braking unit, were used to measure PPO, VGRF, and BV. Load had very large significant effects on PPO (p < 0.001, partial η2 = 0.915); peak VGRF (p < 0.001, partial η2 = 0.854); and peak BV (p < 0.001, partial η2 = 0.973). The PPO and peak BV were the highest at 20% 1RM, though PPO was not significantly greater than that at 30% 1RM. The peak VGRF was significantly greater at 1RM than all other loads, with no significant difference between 20 and 60% 1RM. In resistance trained professional rugby players, the optimal load for eliciting PPO during the loaded JS in the range measured occurs at 20% 1RM JS, with decreases in PPO and BV, and increases in VGRF, as the load is increased, although greater PPO likely occurs without any additional load.     

Sweating responses and the muscle metaboreflex under mildly hyperthermic conditions in sprinters and distance runners

To investigate the effects of different training methods on nonthermal sweating during activation of the muscle metaboreflex, we compared sweating responses during postexercise muscle occlusion in endurance runners, sprinters, and untrained men under mild hyperthermia (ambient temperature, 35°C; relative humidity, 50%). Ten endurance runners, nine sprinters, and ten untrained men (maximal oxygen uptakes: 57.5 ± 1.5, 49.3 ± 1.5, and 36.6 ± 1.6 ml·kg(-1)·min(-1), respectively; P < 0.05) performed an isometric handgrip exercise at 40% maximal voluntary contraction for 2 min, and then a pressure of 280 mmHg was applied to the forearm to occlude blood circulation for 2 min. The Δ change in mean arterial blood pressure between the resting level and the occlusion was significantly higher in sprinters than in untrained men (32.2 ± 4.4 vs. 17.3 ± 2.6 mmHg, respectively; P < 0.05); however, no difference was observed between distance runners and untrained men. The Δ mean sweating rate (averaged value of the forehead, chest, forearm, and thigh) during the occlusion was significantly higher in distance runners than in sprinters and untrained men (0.38 ± 0.07, 0.19 ± 0.03, and 0.11 ± 0.04 mg·cm(-2)·min(-1), respectively; P < 0.05) and did not differ between sprinters and untrained men. Our results suggest that the specificity of training modalities influences the sweating response during activation of the muscle metaboreflex. In addition, these results imply that a greater activation of the muscle metaboreflex does not cause a greater sweating response in sprinters.     

Simulating distal radius fracture strength using biomechanical tests: a modeling study examining the influence of boundary conditions

Distal radius fracture strength has been quantified using in vitro biomechanical testing. These tests are frequently performed using one of two methods: (1) load is applied directly to the embedded isolated radius or (2) load is applied through the hand with the wrist joint intact. Fracture loads established using the isolated radius method are consistently 1.5 to 3 times greater than those for the intact wrist method. To address this discrepancy, a validated finite element modeling procedure was used to predict distal radius fracture strength for 22 female forearms under boundary conditions simulating the isolated radius and intact wrist method. Predicted fracture strength was highly correlated between methods (r = 0.94; p < 0.001); however, intact wrist simulations were characterized by significantly reduced cortical shell load carriage and increased stress and strain concentrations. These changes resulted in fracture strength values less than half those predicted for the isolated radius simulations (2274 ± 824 N for isolated radius, 1124 ± 375 N for intact wrist; p < 0.001). The isolated radius method underestimated the mechanical importance of the trabecular compartment compared to the more physiologically relevant intact wrist scenario. These differences should be borne in mind when interpreting the physiologic importance of mechanical testing and simulation results.     

婴幼儿机械通气时使用右旋美托咪定和咪达唑仑的效果评价

目的:比较婴幼儿在机械通气镇静时使用右旋美托咪定和咪达唑仑效果。方法:收集我院2009年2月至2011年10月入住ICU需要机械通气且镇静时间大于24h的患儿60例,随机分为3组,每组20例,右旋美托咪啶1组(输注剂量为0.25μg.kg-1.h-1,D1组)、2组(输注剂量为0.5μg.kg-1.h-1,D2组)维持镇静,咪达唑仑组(输注剂量为0.05 mg.kg-1.h-1,M组)维持镇静。同时根据病情需要间断给予吗啡镇痛。镇静的疗效评估采用Ramsay镇静评分以及脑电双屏指数(BIS)评价。结果:60例患儿分为3组,每组20例,咪达唑仑组(M组)的输注持续时间(h)为22±8 h,0.25μg(D1组)和0.5μg(D2组)右旋美托咪啶组输注持续时间分别为21±10 h和22±9 h;M组的平均输注速率为0.22±0.05 mg.kg-1.h-1,D1组和D2组平均输注速率分别为0.28±0.07μg.kg-1.h-1和0.21±0.05μg.kg-1.h-1;三组差异无统计学意义。其中M组、D1组、D2组使用吗啡的剂量是分别为36 mg.kg-1.24h-1、29 mg.kg-1.24h-1和20mg.kg-.124h-1。D1组与M组使用吗啡的剂量差异无统计学意义。D2组与M组使用吗啡的剂量差异有统计学意义(P<0.05)。三组患儿BIS值和Ramsay评分监测差异无统计学意义。结论:右旋美托咪啶应用于婴幼儿是安全有效的,0.5μg.kg-1.h-1右旋美托咪啶组镇静更加有效,24小时吗啡的使用剂量显著减少。     

Effects of eight weeks of caffeine supplementation and endurance training on aerobic fitness and body composition

The purpose of this study was to examine the effects of daily administration of a supplement that contained caffeine in conjunction with 8 weeks of aerobic training on VO(2)peak, time to running exhaustion at 90% VO(2)peak, body weight, and body composition. Thirty-six college students (14 men and 22 women; mean +/- SD, age 22.4 +/- 2.9 years) volunteered for this investigation and were randomized into either a placebo (n = 18) or supplement group (n = 18). The subjects ingested 1 dose (3 pills = 201 mg of caffeine) of the placebo or supplement per day during the study period. In addition, the subjects performed treadmill running for 45 minutes at 75% of the heart rate at VO(2)peak, three times per week for 8 weeks. All subjects were tested pretraining and posttraining for VO(2)peak, time to running exhaustion (TRE) at 90% VO(2)peak, body weight (BW), percentage body fat (%FAT), fat weight (FW), and fat-free weight (FFW). The results indicated that there were equivalent training-induced increases (p < 0.05) in VO(2)peak and TRE for the supplement and placebo groups, but no changes (p > 0.05) in BW, %FAT, FW, or FFW for either group. These findings indicated that chronic use of the caffeine-containing supplement in the present study, in conjunction with aerobic training, provided no ergogenic effects as measured by VO(2)peak and TRE, and the supplement was of no benefit for altering body weight or body composition.     

Effect of repeated eCG treatments and ovum pick-up on ovarian response and oocyte recovery during early pregnancy in suckling beef cows

This study was designed to evaluate in suckling early pregnant beef cows with and without eCG-pre-stimulation: (i) the influence of day gestation (from 40 to 101 days) and the consecutive eCG treatments on the follicular growth induced by means of ultrasound-guided transvaginal follicle ablation (FA; all follicles ≥ 5 mm) and the number and quality oocytes recovered by ovum pick-up (OPU) and (ii) the possible effects of repeated hormonal stimulation and FA/OPU on pregnancy outcome. Twelve suckling early pregnant Angus cows (40 days post fixed-time artificial insemination) were randomly assigned to each of two groups (n=6 group(-1)). Group 1 treatments included: FA (Day 0), eCG (1600 IU; Day 1) and OPU (Day 5). Group 2: as cited Group 1 with no eCG treatment. In both groups, OPU was repeated five times (Days 45, 59, 73, 87 and 101 of gestation). The numbers (mean ± SEM) of class II (5-9 mm; 4.3 ± 0.9) and class III (≥10 mm; 2.5 ± 0.4) follicles visualized per cow per OPU session in eCG-treated cows were greater (P<0.05) than for non-treated cows (0.9 ± 0.1 and 0.9 ± 0.1, respectively). In contrast, the number (mean ± SEM) of class I (<5mm) follicles per cow per OPU session was lower for cows with eCG treatment (2.8 ± 0.4) than for non-treated cows (5.7 ± 0.5). The mean number of aspirated follicles was not significantly different (P<0.05) between eCG-treated cows and non-treated cows at 45 and 59 days of pregnancy. However, the mean number of aspirated follicles was greater (P=0.03) in eCG-treated cows than non-treated cows from 73 day of pregnancy onwards. The numbers (mean ± SEM) of recovered oocytes and viable oocytes/cow/session were greater (P<0.05) for eCG-treated cows (2.2 ± 0.2 and 1.6 ± 0.4, respectively) than for non-treated cows (1.0 ± 0.2 and 0.9 ± 0.2, respectively). No donor pregnancies were lost either during or following OPU procedure. We can conclude that (1) eCG-treated pregnant suckled cows can be a source of oocytes for IVF at least to 100 days of gestation and (2) repeated FA/eCG treatment/OPU procedures did not affect the pregnancy outcome.     

Evaluation of the BOD POD and leg-to-leg bioelectrical impedance analysis for estimating percent body fat in National Collegiate Athletic Association Division III collegiate wrestlers

The purpose of this study was to compare percent body fat (%BF) estimated by air displacement plethysmography (ADP) and leg-to-leg bioelectrical impedance analysis (LBIA) with hydrostatic weighing (HW) in a group (n = 25) of NCAA Division III collegiate wrestlers. Body composition was assessed during the preseason wrestling weight certification program (WCP) using the NCAA approved methods (HW, 3-site skinfold [SF], and ADP) and LBIA, which is currently an unaccepted method of assessment. A urine specific gravity less than 1.020, measured by refractometry, was required before all testing. Each subject had all of the assessments performed on the same day. LBIA measurements (Athletic mode) were determined using a Tanita body fat analyzer (model TBF-300A). Hydrostatic weighing, corrected for residual lung volume, was used as the criterion measurement. The %BF data (mean +/- SD) were LBIA (12.3 +/- 4.6), ADP (13.8 +/- 6.3), SF (14.2 +/- 5.3), and HW (14.5 +/- 6.0). %BF estimated by LBIA was significantly (p < 0.01) smaller than HW and SF. There were no significant differences in body density or %BF estimated by ADP, SF, and HW. All methods showed significant correlations (r = 0.80-0.96; p < 0.01) with HW. The standard errors of estimate (SEE) for %BF were 1.68, 1.87, and 3.60%; pure errors (PE) were 1.88, 1.94, and 4.16% (ADP, SF, and LBIA, respectively). Bland-Atman plots for %BF demonstrated no systematic bias for ADP, SF, and LBIA when compared with HW. These preliminary findings support the use of ADP and SF for estimating %BF during the NCAA WCP in Division III wrestlers. LBIA, which consistently underestimated %BF, is not supported by these data as a valid assessment method for this athletic group.