Scale model on performance prediction in recreational and elite endurance runners

Purpose: To identify the effect of allometric scaling on the relationship between running efficiency (REff) and middle-distance-running performance according to performance level. Methods: Thirteen male recreational middle-distance runners (mean ± SD age 33.3 ± 8.4 y, body mass 76.4 ± 8.6 kg, maximal oxygen uptake [VO2max] 52.8 ± 4.6 mL · kg-1 · min-1; G1) and 13 male high-level middle-distance runners (age 25.5 ± 4.2 y, body mass 62.8 ± 2.7 kg, VO2max 70.4 ± 1.9 mL · kg-1 · min-1; G2) performed a continuous incremental test to volitional exhaustion to determine VO2max and a 6-min submaximal running test at 70% of VO2max to assess REff. Results: Significant correlation between REff and performance were found for both groups; however, the strongest correlations were observed in recreational runners, especially when using the allometric exponent (respectively for G1, nonallometric vs allometric scaling: r =.80 vs r =.86; and for G2, nonallometric vs allometric scaling: r =.55 vs r =.50). Conclusion: These results indicate that an allometric normalization may improve endurance-performance prediction from REff values in recreational, but not in elite, runners. © 2014 Human Kinetics, Inc

Influence of the allometric model on relationship between running economy and performance in long-distance runners

The aim was investigated the effect of allometric model in relationship between maximal Oxygen uptake (VO2max) and long-distance running performance. Twelve runners (age: 28.6 ± 7.4 years, body mass: 67.9 ± 9.4 kg, height: 1.71 ± 0.7 m) were submitted to an incremental treadmill running protocol for determination of VO2max and participated in a trail of 10.000 m. despite the significant differences found between the forms of relativization of VO2max (by total body mass, allometric exponent for sampling and lean body mass), the strong correlations verified between VO2max and performance show that this prediction is independent of how the VO2max is relativized

Transfer of strength training to running mechanics, energetics, and efficiency

To examine the effects of increased strength on mechanical work, the metabolic cost of transport (Cost), and mechanical efficiency (ME) during running. Fourteen physically active men (22.0 ± 2.0 years, 79.3 ± 11.1 kg) were randomized to a strength-training group (SG, n = 7), who participated in a maximal strength training protocol lasting 8 weeks, and a control group (CG, n = 7), which did not perform any training intervention. Metabolic and kinematic data were collected simultaneously while running at a constant speed (2.78 m·s-1). The ME was defined as the ratio between mechanical power (Pmec) and metabolic power (Pmet). The repeated measures two-way ANOVA did not show any significant interaction between groups, despite some large effect sizes (d): internal work (Wint, p = 0.265, d = -1.37), external work (Wext, p = 0.888, d = 0.21), total work (Wtot, p = 0.931, d = -0.17), Pmec (p = 0.917, d = -0.17), step length (SL, p = 0.941, d = 0.24), step frequency (SF, p = 0.814, d = -0.18), contact time (CT, p = 0.120, d = -0.79), aerial time (AT, p = 0.266, d = 1.12), Pmet (p = 0.088, d = 0.85), and ME (p = 0.329, d = 0.54). The exception was a significant decrease in Cost (p = 0.047, d = 0.84) in SG. The paired t-test and Wilcoxon test only detected intragroup differences (pre- vs. post-training) for SG, showing a higher CT (p = 0.041), and a lower Cost (p = 0.003) and Pmet (p = 0.004). The results indicate that improved neuromuscular factors related to strength training may be responsible for the higher metabolic economy of running after 8 weeks of intervention. However, this process was unable to alter running mechanics in order to indicate a significant improvement in ME

Mechanical work and long-distance performance prediction: The influence of allometric scaling

The purpose of this study was to examine the effect of allometric scaling on the relationship between mechanical work and long-distance running performance in recreational runners. Fourteen recreational long-distance runners (male, mean ± SD - age: 29 ± 7 years; body mass: 70.0 ± 10.2 kg; body height: 1.71 ± 0.07 m; maximal oxygen uptake: VO 2max 52.0 ± 4.9 ml.kg-1.min-1) performed two tests: a continuous incremental test to volitional exhaustion in order to determine VO2max, and a 6-minute running submaximal test at 3.1 m.s-1, during which segments in the sagittal plane were recorded using a digital camera and the internal (Wint), external (Wext) and total (Wtot) mechanic work, in J.kg-1.m-1, was subsequently calculated. The results indicated a significant correlation between mechanical work and performance, however, the strongest correlations were observed when allometric exponents were used (respectively for Wint, Wext and Wtot; non allometric vs. allometric scaling defined by literature (0.75) or determined mathematically (0.49): r = 0.38 vs. r = 0.44 and r = 0.50; r = 0.80 vs. r = 0.83 and r = 0.82; r = 0.70 vs. r = 0.77 and r = 0.78). These results indicate that mechanical work could be used as a predictor of recreational long-distance performance and an allometric model may improve this prediction. © Editorial Committee of Journal of Human Kinetics

Energetic responses of head-out water immersion at different temperatures during post-exercise recovery and its consequence on anaerobic mechanical power

Purpose: While exercise recovery may be beneficial from a physiological point of view, it may be detrimental to subsequent anaerobic performance. To investigate the energetic responses of water immersion at different temperatures during post-exercise recovery and its consequences on subsequent anaerobic performance, a randomized and controlled crossover experimental design was performed with 21 trained cyclists. Method: Participants were assigned to receive three passive recovery strategies during 10 min after a Wingate Anaerobic Test (WAnT): control (CON: non-immersed condition), cold water immersion (CWI: 20 °C), and hot water immersion (HWI: 40 °C). Blood lactate, cardiorespiratory, and mechanical outcomes were measured during the WAnT and its recovery. Time constant (τ), asymptotic value, and area under the curve (AUC) were quantified for each physiologic parameter during recovery. After that, a second WAnT test and 10-min recovery were realized in the same session. Results: Regardless the water immersion temperature, water immersion increased τV ̇O2 (+ 18%), asymptote (V ̇O2 + 16%, V ̇CO2 + 13%, V ̇ E + 17%, HR + 16%) and AUC (V ̇O2 + 27%, V ̇CO2 + 18%, V ̇ E + 20%, HR + 25%), while decreased τHR (− 33%). There was no influence of water immersion on blood lactate parameters. HWI improved the mean power output during the second WAnT (2.2%), while the CWI decreased 2.4% (P < 0.01). Conclusion: Independent of temperature, water immersion enhanced aerobic energy recovery without modifying blood lactate recovery. However, subsequent anaerobic performance was increased only during HWI and decreased during CWI. Despite higher than in other studies, 20 °C effectively triggered physiological and performance responses. Water immersion-induced physiological changes did not predict subsequent anaerobic performance