***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Abstract In modern sprint cross-country skiing , strength and maximal speed are major determinants of performance . The aims of this study were to ascertain the anthropometric characteristics of world-class sprint skiers and to evaluate whether a specific body composition and /or body dimension characterizes a successful sprint skier . Our hypothesis was that body height and lean body mass are related to peak speed in double poling and diagonal stride . Fourteen male national and international elite skiers performed two peak speed tests in double poling and diagonal stride roller skiing on a treadmill and were analysed using dual-energy X-ray absorptiometry to determine body composition and body dimensions . Relative pole length was positively correlated with both techniques ( double poling : r = 0.77 , P < 0.01 ; diagonal stride : r = 0.60 , P < 0.05 ) and was the only variable that was part of the multiple regression model for both double poling and diagonal stride peak speed . Body height was not correlated with any technique , whereas lean trunk mass ( r = 0.75 , P < 0.01 ) , body mass index ( r = 0.66 , P < 0.01 ) , total lean mass ( r = 0.69 , P < 0.01 ) , and body mass ( r = 0.57 , P < 0.05 ) were positively related to double poling peak speed . Total lean mass ( absolute : r = 0.58 , P < 0.05 ; relative : r = 0.76 , P < 0.001 ) and relative lean mass of the trunk , arms ( both r = 0.72 , P < 0.01 ) , and legs ( r = 0.54 , P < 0.05 ) were positively related to diagonal stride peak speed . In conclusion , skiers should aim to achieve a body composition with a high percentage of lean mass and low fat mass . A focus on trunk mass through increased muscle mass appears to be important , especially for double poling . The use of longer poles ( percent body height ) seems to be advantageous for both double poling and diagonal stride peak speed , whereas body dimensions do not appear to be a predictive factor There is still considerable debate and some confusion as to the most appropriate method of scaling or normalizing maximum oxygen uptake ( V̇O2max ) for differences in body mass ( m ) in both adults and children . Previous studies on adult population s have demonstrated that although the traditional ratio st and ard V̇O2max ( ml kg−1 min−1 ) fails to render V̇O2max independent of body mass , the ratio st and ard is still the best predictor of running performance . However , no such evidence exists in children . Hence , the purpose of the present study was to investigate whether the ratio st and ard is still the most appropriate method of normalising V̇O2max to predict 1-mile run speed in a group of 12-year-old children ( n=36 ) . Using a power function model and log-linear regression , the best predictor of 1-mile run speed was given by : speed ( m s−1)=55.1V̇O2max0.986m−0.96 . With both the V̇O2max and body mass exponents being close to unity but with opposite signs , the model suggest the best predictor of 1-mile run speed is almost exactly the traditional ratio st and ard recorded in the units ( ml kg−1 min−1 ) . Clearly , reporting the traditional ratio st and ard V̇O2max , recorded in the units ( ml kg−1 min−1 ) , still has an important place in publishing the results of studies investigating cardiovascular fitness of both children and adults Little is known about the relationship among  training  , energy expenditure , muscle volume , and fitness in prepubertal girls . Because physical activity is high in prepubertal children , we hypothesized that there would be no effect of training . Forty pre- and early pubertal ( mean age 9.1 + /- 0.1 yr ) nonobese girls enrolled in a 5 day/wk summer school program for 5 wk and were r and omized to control ( n = 20 ) or training groups ( n = 20 ; 1.5 h/day , endurance-type exercise )  .  Total energy expenditure ( TEE ) was measured using doubly labeled water , thigh muscle volume using magnetic resonance imaging , and peak O(2 ) uptake ( VO(2 peak ) ) using cycle ergometry .  TEE was significantly greater ( 17 % , P < 0.02 ) in the training girls . Training increased thigh muscle volume ( + 4.3 + /- 0.9 % , P < 0.005 ) and VO(2 peak ) ( + 9.5 + /- 6 % , P < 0.05 ) , effects surprisingly similar to those observed in adolescent girls using the same protocol ( Eliakim A , Barstow TJ , Brasel JA , Ajie H , Lee W-NP , Renslo R , Berman N , and Cooper DM , J Pediatr 129 : 537 - 543 , 1996 ) . We further compared these two sample population s : thigh muscle volume per weight was much lower in adolescent compared with prepubertal girls ( 17.0 + /- 0.3 vs. 27.8 + /- 0.6 ml/kg body mass ; P < 0.001 ) , and allometric analysis revealed remarkably low scaling factors relating muscle volume ( 0.34 + /- 0.05 , P < 0.0001 ) , TEE ( 0.24 + /- 0 . 06 , P < 0.0004 ) , and VO(2 peak ) ( 0.28 + /- 0.07 , P < 0.0001 ) to body mass in all subjects . Muscle and cardiorespiratory functions were quite responsive to brief training in prepubertal girls . Moreover , a retrospective , cross-sectional analysis suggests that increases in muscle mass and VO(2 peak ) may be depressed in nonobese American girls as they mature Maximal oxygen uptake ( VO2max ) in females , expressed as ml x kg(-1 ) x min(-1 ) , declines steadily during the first three decades of life . The contribution of diminished cardiovascular function to this apparent fall in aerobic fitness is unknown . Cardiac responses to maximal cycle exercise were compared in 24 premenarcheal females ( mean age 11.7 years ) and 17 young adult women ( mean age 27.4 years ) using Doppler echocardiography .  Mean VO2max was 40 ml x kg(-1 ) x min(-1 ) and 34.7 ml x kg(-1 ) x min(-1 ) in the girls and women , respectively ( p < 0.05 ) . When VO2max was expressed relative to allometrically-derived mass(0.52 ) , however , no significant difference was observed in aerobic fitness between the two groups . Similar allometric analyses revealed no significant differences in average maximal cardiac output ( 10.50 vs 10.07 L x min(-1 ) BSA(-1.11 ) for girls and women , respectively ) nor maximal stroke volume ( 53 vs 56 ml BSA(-1.13 ) respectively ) . These findings suggest that 1 ) allometric scaling is important in eliminating the effects of body size on VO2max , 2 ) body dimension differences can account for variations in VO2 in young females , and 3 ) cardiac functional reserve is similar in premenarcheal girls and young adult women PURPOSE Anthropometric ( ANTHRO ) and dual-energy x-ray absorptiometric ( DEXA ) estimates of total body and leg fat-free masses ( FFM ) were obtained in 77 r and omly selected sedentary men and women , aged 20 - 80 : inter method limits of agreement and their clinical significance , as inferred from the differences on peak VO2 corrected for FFMANTHRO and FFMDEXA , were determined . METHODS Limits of agreement were calculated as mean bias + /- 95 % confidence intervals : peak VO2 at maximum cycle ergometry was related to FFMANTHRO and FFMDEXA by using both st and ard ( y x x(-1 ) ) and power function ratios ( allometry ) . RESULTS Data distribution of the ANTHRO-DEXA differences presented significant heteroscedasticity in both sexes , i.e. , differences were proportional to the mean ( P < 0.05 ) . After logarithmic transformation , the mean bias + /- 95 % limits of agreement were expressed as ratios ( ANTHRO x DEXA(-1 ) x// error ratio ) : these corresponded to 0.95 x// 1.11 or 0.99 x// 1.15 for total body FFM and 0.90 x// 1.10 or 1.02 x// 1.07 for leg FFM in men and women , respectively . In addition , we found different allometric exponents for FFMANTHRO and FFMDEXA : the inter method differences , therefore , increased after power function expression ( P < 0.05 ) . CONCLUSION Discrepancies between ANTHRO and DEXA measurements of FFM depend on the magnitude of the estimate : differences are typically within 10 to 15 % . Importantly , FFM-corrected peak VO2 values can vary according to the method chosen for body composition assessment , especially when allometry is used for peak VO2 correction . These results demonstrate that ANTHRO-DEXA differences in FFM estimation do have relevant practical consequences for the analysis of maximum aerobic capacity in nontrained humans The method of removing the confounding effect of body mass on peak oxygen uptake simply by dividing the measured values by body mass has been question ed . The aim of the study was to find an expression of body mass for compensating for differences in body mass so as to achieve the best correlation to running performance . In a cross-sectional study , design  peak oxygen uptake ( VO2peak ) was measured in 107 boys in the age range 8 - 17 years and 88 girls in the age range 8 - 16 years . The present study indicates that VO2peak do not increase in proportion to body mass during running , rather that VO2peak is inversely related to body mass . When using allometric regression st and ards with the sexes separated in gender groups , there was a tendency that boys achieved scaling factors closer to unity than did the girls . The increase in subcutaneous fat in the girls throughout the pubertal years is the most likely reason why body mass increased proportionally more than VO2peak in girls . The present study indicates that VO2peak when expressed as milliliters per kilogram per minute ( ml kg(-1 ) min(-1 ) ) is a poor denominator for VO2peak as a function of running performance in children and adolescents Background Statistical methods for inferring the true magnitude of an effect from a sample should have acceptable error rates when the true effect is trivial ( type I rates ) or substantial ( type II rates ) . Objective The objective of this study was to quantify the error rates , rates of decisive ( publishable ) outcomes and publication bias of five inferential methods commonly used in sports medicine and science . The methods were conventional null-hypothesis significance testing [ NHST ] ( significant and non-significant imply substantial and trivial true effects , respectively ) ; conservative NHST ( the observed magnitude is interpreted as the true magnitude only for significant effects ) ; non- clinical magnitude-based inference [ MBI ] ( the true magnitude is interpreted as the magnitude range of the 90 % confidence interval only for intervals not spanning substantial values of the opposite sign ) ; clinical MBI ( a possibly beneficial effect is recommended for implementation only if it is most unlikely to be harmful ) ; and odds-ratio clinical MBI ( implementation is also recommended when the odds of benefit outweigh the odds of harm , with an odds ratio > 66 ) . Methods Simulation was used to quantify st and ardized mean effects in 500,000 r and omized , controlled trials each for true st and ardized magnitudes ranging from null through marginally moderate with three sample sizes : suboptimal ( 10 + 10 ) , optimal for MBI ( 50 + 50 ) and optimal for NHST ( 144 + 144 ) . Results Type I rates for non- clinical MBI were always lower than for NHST . When type I rates for clinical MBI were higher , most errors were debatable , given the probabilistic qualification of those inferences ( unlikely or possibly beneficial ) . NHST often had unacceptable rates for either type II errors or decisive outcomes , and it had substantial publication bias with the smallest sample size , whereas MBI had no such problems . Conclusion MBI is a trustworthy , nuanced alternative to NHST , which it outperforms in terms of the sample size , error rates , decision rates and publication bias Objective : The present study analysed the allometric relationship ( MR = a · Mb ) between human metabolic rate ( MR ) , ranging from resting to maximal metabolic conditions , and body mass ( M ) , both in athletes of different specialization and untrained individuals . Subjects and methods : Two hundred and seventy male athletes and 43 untrained men performed a continuous incremental test to volitional exhaustion on a motorized treadmill . Metabolic rate ( i.e. ) was measured during resting ( ) , sub-maximal ( walking at 5 km h−1 ; running at 7.5 km h−1 ; ventilatory anaerobic threshold ) and maximal exercise conditions ( maximum oxygen uptake ) . Results : A significant difference ( p < 0.001 ) in the MR – body mass relationships between athletes and controls was found . For the control group , the mass exponent b exhibited a non-significant ( p = 0.37 ) increase with increasing metabolic dem and ( b = 0.69 , 0.76 , 0.76 , 0.84 , and 0.89 , for , , , , and , respectively ) . In contrast , the corresponding mass exponent for the athletic group significantly ( p < 0.01 ) decreased when moving from resting to maximal metabolic conditions ( b = 0.98 , 0.88 , 0.80 , 0.69 , and 0.67 ) . Conclusion : These results indicate that the recently proposed allometric cascade model may be valid in describing the scaling behaviour of MR in untrained individuals , but 
    Output:
    
We conclude that the scaling of $ $ { \dot{\text{V}}\text{O}}$$V˙O2max in humans is consistent with the allometric cascade model with an estimated prediction interval for the fat-free mass exponent not likely to be consistent with the $ $ \frac{2}{3}\text { and } \frac{3}{4}$$23 and 34 power laws