The influence of the allometric scale on the relationship between running economy and biomechanical variables in distance runners

Studies have demonstrated the need for the use of parameters that diminish the effect of body mass, for intra and inter group comparison, in individuals with different masses in order to provide a different analysis on the behaviour of the relation between running economy (RE) and biomechanical variables (BVs). The allometric scale is represented by a regression equation that indicates the behaviour of a physiological variable in relation to the variable mass (RE=a.xb), where x is body mass in (kg) and the dimensionless coefficient a is characteristic of the species analysed, and the dimensionless exponent b determines the percentage of mass to be associated with the physiological variable. The influence of the allometric scale (b=-1; -0.75; -0.73; -0.67) on the relationship between RE and BVs - stride length (SL), relative stride length (RSL), stride rate (SR), stride time (ST), support time (SUPT) and balance time (BALT) - at 12 km.h-1, was analysed in nine elite runners. Factorial analysis and Pearson's Correlation Coefficient test (r) with P<0.05 were used. A decrease in the explanation power of the RE was observed, with the use of the allometric exponent, due to the BVs, as well as a reduction of the correlation coefficients between SL versus RE, ST versus RE and SR versus RE. The BALT presented a higher correlation where b=-0.75. The RSL and SUPT presented non-significant correlations. The variables SL, ST, SR and BALT were the most effective predictors of the RE, Where: b=-1, the allometric scale was most efficient to predict the running performance

Application of the allometric scale for the submaximal oxygen uptake in runners and rowers

Background: The aim of the current study was to determine the allometric exponents for runners and rower’s metabolic cost, while also verifying the relation of performance with and without the allometric application. Methods: Eleven runners (age: 22.3±10.4 years; height: 174±8.8 cm; body mass: 61.7±9.3 kg; maximum oxygen uptake ( •VO2max): 56.3±3.9 ml.kg[sup]-1[/sup].min[sup]-1[/sup]) and fifteen rowers (age: 24±5.4 years; height: 185.5±6.5 cm; body mass: 83.5±7.2 kg; •VO2max: 61.2±3.4 ml.kg[sup]-1[/sup].min[sup]-1[/sup]) carried out a specific progressive maximum test. The allometric exponent was determined from the logarithmic equation Log y = Log b Log x, where x is the mass, y is the VO2max (l.min[sup]-1[/sup]), a is one constant and b is the allometric exponent. The data were analyzed using descriptive and comparative statistics (independent T test of the Student), with p<0.05 (SPSS version 13.0). Results: The allometric exponent of the rowers was 0.70 and that of the runners was 1.00. Significant differences were found between the fat mass percentage, with higher value for rowers, suggesting that this variable may influence the behavior of the allometric exponent and consequently of the basal metabolic rate. Conclusions: Scaling may help in understanding variation in aerobic power and in defining the physiological limitations of work capacity

Physiologic and Kinematical Effects of Water Run Training on Running Performance

The purpose of this study was to analyze whether trained competitive runners could maintain running kinematics, cardiorespiratory performance (VO2peak, ventilatory threshold, running economy) and on-land running performance by replacing 30% of conventional training with water run training during 8 weeks. Eighteen runners were divided in two groups: on-land run (OLR Group) and deep water run (DWR Group). The DWR Group replaced 30% of training volume on land with DWR and the OLR group trained only on land (both groups undertaken workouts 6-7 d.wk-1 for a total of 52 sessions). No significant intra- or intergroup differences were observed for VO2peak in the DWR Group and OLR Group. Similarly, ventilatory threshold second was unaltered in the DWR Group and OLR Group. Regarding running economy (at 14 km.h-1) also, no intra- or intergroup differences were found in the DWR Group (pre = 43.4 ± 5.0, post = 42.6 ± 3.85 ml.kg-1.min-1) and OLR Group (pre = 43.9 ± 2.5, post = 42.6 ± 2.6 ml.kg-1.min-1). Kinematic responses were similar within and between groups. Water running may serve as an effective supplementary training over a period of 8 weeks up to 30% of land training volume for competitive runners

KINEMATIC ANALYSIS OF MIDDLE-DISTANCE RUNNERS DURING TREADMILL RUNNING AND DEEP WATER RUNNING

The present study compared the kinematics of treadmill running (TR) with deep water running (DWR). Five male middle-distance runners of national level were requested to run in intensities of regenerative effort, long aerobic, 5/10 km, 400/800 m and 100/200 m on treadmill and water. Three complete running steps were recorded. Two-dimensional analysis methods were employed to analyse the lower limb movement and general kinematics. The results revealed diferences (