2000 Pre-Olympic Congress Sports Medicine and Physical Education International Congress on Sport Science 7-13 September - Brisbane, Australia 2000

Energy cost and running economy of Australian surf iron men and trained male runners running on soft dry beach sand and grass H. Pinnington* & B. Dawson Department of Human Movement and Exercise Science, The University of Western Australia To compare the energy cost (EC) and running economy of habitual and non-habituated sand surface runners, five elite Western Australian iron men (mean VO2 max 62.8 ml×kg-1×min-1) performed steady state running trials on grass (in shoes) at 8, 11 and 14 km×h-1 and on sand at 8 and 11 km×h-1 (barefoot and in shoes) for the measurement of VO2 and VCO2 using a portable gas analysis system (Cosmed K4 b2). Net aerobic EC (J×kg-1×min-1) was determined from net steady state VO2 and RER and net anaerobic EC from lactate accumulation. Data from seven trained male "non-sand" runners (mean VO2 max 56.9 ml×kg-1×min-1) who performed similar running trials on grass and sand (Pinnington and Dawson, 1999) were used for the running economy comparisons. For the 8 and 11 km×h-1 iron man running trials the sand barefoot and sand in shoes results for net aerobic EC and total (aerobic and anaerobic) net EC were significantly greater (P<0.001) than the grass running values. No differences existed between the sand barefoot and sand in-shoes trials. Also there were no differences between the three surface condition values for net anaerobic EC for either the 8 or 11 km×h-1 running speeds. Running economy (J×kg-1×m-1×min-1) comparisons in net aerobic EC for the iron men and "non-sand" runners revealed slightly lower values (NS) in the iron men for all three surface conditions, but iron man values for net anaerobic EC running on grass, sand barefoot and sand in shoes were significantly less (P<0.05) than the "non-sand" runners' values. Respective values for total net EC for the iron men and recreational runners were; Grass 4.93 ± 0.6, 5.44 ± 1.0, (NS); Sand barefoot 6.61 ± 0.8, 8.75 ± 1.4, (P<0.001); Sand in shoes 6.82 ± 0.7, 8.62 ± 1.4, (P<0.001). These results indicate that habitual sand running specifically improves running economy on sand. The lower lactate accumulation in the iron men when running on grass and sand suggests sand running training may reduce lactate production and/or improve lactate resynthesis, reducing fatigue when running on firm or soft surfaces.  Reference: Pinnington and Dawson (1999) Fifth IOC World Congress of Sports Sciences, Book of Abstracts, p.41

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