Impellizzeri FM¹, Arcelli E¹, Rampinini E¹, La Torre²A, Faina M³, Sassi A¹

1, Lab of Physiology, Sport Service MAPEI srl, Castettanza (VA), Italy;2, Facoltà di Scienze Motorie, Università degli Studi, Milano, Italy;3, Istituto di Scienze dello Sport, CONI, Roma, Italy

Several studies have investigated the physiological determinants of performance in medium and low level race-walkers. For example, Hagberg and Coyle (1983) studied eight male race-walkers with a mean 20 km race time of 112 ± 6 min founding significant correlations between 20 km race pace and oxygen consumption (VO₂) at LT, velocity at LT, and economy at 10 km-h^-1. Similar results were found by Yoshida et al (1989) in eight female race-walkers with a mean velocity during 5 km ranged from 168.6 to 212.9 nvmin^-1. The aim of this study was to compare the physiological characteristics of a group of male and female race-walkers of higher level than previous investigations, divided in two subgroups of different performance capacity. Ten male (mean age 24.8 ± 4.2 yrs, weight 64.4 ± 7.0 kg, height 175.9 ± 3.8 cm) and eight females (mean age 22.6 ± 6.1 yrs, weight 51.4 ± 6.1 kg, height 165.3 ± 7.2 cm) competitive race-walkers of international and national level. They performed an incremental test on a treadmill starting from 5 krn-h”1 and increasing the velocity of 2 km-J^ every 8 min until 15 km-h^-1, as for higher velocity the corrected race technique were not assured. Curing the tests, expired respiratory gases were measured using an automated gas analysis system. From these data, economy at each velocity was calculated using the formula of Di Prampero: [(VO₂-VO_2rest)v”1]60. Capillary blood samples were immediately analysed using an electroenzymatic technique at the end of each step. From the lactate data LT proposed by Hagberg and Coyle (1983) and the lactate threshold at 4 mmol (OBLA) were calculated. Race-walkers were divided in function of their best time obtained two months after the test session (20 km mean time of 86.8 ± 4.7 min for male and 10 km mean time of 48.2 ±3.8 min for female) in two groups “Best” (best 5 males and 4 females) and “Worst” (worst 5 males and 4 females). To compare the data of the two groups a Student /-test for unpaired data was used. Between the two groups no statistical significantly differences were found for velocity and VO₂ corresponding to LT and OBLA. On the other hand, significant differences were found in economy at 9, 11,13 km-h^-1 (pO.O1) and at 15 km-h^-1 (p<0.05). The results of this study showed that in a group of high level race-walkers with similar LT and OBLA, the main determinant of performance is economy. This confirms the finding of Hagberg and Coyle (1983) who showed that in lower level race-walkers with similar LT, differences in performance were due to submaximal economy.

7th Annual Congress of the European College of Sport Science (ECSS).

Athens, Greece, July 24 – 28, 2002

Book of Abstract ECSS Athens, 07-0726