09 April 2014

Running on snow and sand – the importance of the ground surface for training and racing

It is snowing again today in Uppsala and it took an unusually long time to run to work, not only due to the wet and cold northerly winds blowing in my face, but also due to the slippery ground surface. If this had been November I would have been thrilled by the snowfall, but in April it is only depressing as the snow will anyway not linger long. It clearly hampered my run today and made me think about how much more difficult it would be to run on snow than on asphalt and gravel roads for instance. I looked for literature on the subject, but could not find any studies on the subject. It appears that you should not run on snow, but rather ski, something humans apparently has done since at least 2000 BC (Formenti et al “Human locomotion on snow: determinants of economy and speed of skiing across the ages” Proc R Soc B 2005; 272: 1561-1569).

How I feel about the first snow of the season. Picture from the Whatisultra webpage (http://whatisultra.tumblr.com)

How I feel about snow in the middle of April. Picture from the Whatisultra webpage (http://whatisultra.tumblr.com)  

If there is no data on running on snow there is plenty of data on running and training on sand (“beach running”). A good recent review on the subject is Binnie et al “Sand training: a review of current research and practical applications” J Sports Sci 2014; 32: 8-15. The energy cost of running and walking on sand is clearly higher, approximately 1.5 times higher, than running or walking on grass or firm surfaces (see for instance Zamparo et al “The energy cost of walking or running on sand” Eur J Appl Physiol Occup Physiol. 1992; 65:183-7; Lejeune et al “Mechanics and energetics of human locomotion on sand” J Exp Biol. 1998; 201: 2071-80; Pinnington &  Dawson “The energy cost of running on grass compared to soft dry beach sand” J Sci Med Sport. 2001; 4: 416-30; Pinnington et al “Kinematic and electromyography analysis of submaximal differences running on a firm surface compared with soft, dry sand” Eur J Appl Physiol. 2005; 94: 242-53; and Davies & Mackinnon “The energetics of walking on sand and grass at various speeds” Ergonomics. 2006; 49: 651-60 ). The higher energy cost when running on sand might be due to reduced recovery of elastic energy through decreased efficiency of positive work done by the muscles and tendons and higher mechanical work done (for instance through greater hip and knee range of motion compared with firm surface running). Compared to running on harder surfaces sand will give rise to lower impact forces and this can limit muscle damage and muscle soreness and running on sand is therefore often recommended in rehabilitation training. There exists also plenty of very interesting data on the effects of running on uneven ground and I will discuss this in a later blog post. Both uneven ground and plenty of sand is now currently facing the runners of the 29th edition of Marathon des Sables (MdS) now going on in Sahara. It is now in stage 4 and a good coverage after each stage is posted by Ian Corless at Talk Ultra Podcast 


Running in sand dunes at MdS 2014. Picture from http://iancorless.org


 

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