Original articles  EXERCISE PHYSIOLOGY AND BIOMECHANICS 

The Journal of Sports Medicine and Physical Fitness 2003 September;43(3):285-90

Copyright © 2009 EDIZIONI MINERVA MEDICA

language: English

Effects of drafting on energy expenditure in in-line skating

Millet G. P., Geslan R., Ferrier R., Candau R., Varray A.

Faculté des Sciences du Sport Université de Montpellier, Montpellier, France

Aim. The pur­pose of ­this ­study was to meas­ure the ­effects of draft­ing on ener­gy expen­di­ture in in-­line skat­ing, and to inves­ti­gate wheth­er the “ben­e­fit of draft­ing”, i.e. the ­decrease in ener­gy expen­di­ture, was dif­fer­ent ­between two veloc­ities and two dis­tanc­es sep­ar­at­ing the two skat­ers.
Meth­ods. ­Eight rec­re­a­tion­al in-­line skat­ers per­formed six exer­cis­es of 6 min, at 2 veloc­ities (V1 = 5.51±0.45 m·sec-1; V2 = 7.01±0.67 m·sec-1) in 3 con­di­tions (ND = with­out draft­ing; D1=0.74-0.87 m “­close”; D2 = 1.19-1.36 m “far”). Col­lec­tion of ­expired gas was car­ried out ­using a ­breath-by-­breath port­able gas anal­y­ser K4b2 and the dis­tance ­between the skat­ers was meas­ured by vid­eo anal­y­sis.
­Results. The ­skaters’ ener­gy expen­di­ture was ­reduced in all draft­ing con­di­tions; ­between D1 and ND by 9.6±4.4% at V1 and by 2.7±3.3% at V2; ­between D2 and ND by 8.8±6.0% at V1 and by 4.2±4.8% at V2. ­This reduc­tion was sig­nif­i­cant­ly (p<0.05) ­more impor­tant at V1 ­than V2 and no dif­fer­enc­es ­were ­observed ­between D1 and D2.
Con­clu­sion. In in-­line skat­ing, the tech­ni­cal dif­fi­cul­ties for draft­ing effi­cient­ly, espe­cial­ly ­while cor­ner­ing, result­ed in a ­reduced “ben­e­fit of draft­ing” at ­high veloc­ity ­than in oth­er ­sports. More­over, the ­need for the sub­ject to ­adjust ­their own ­cycle fre­quen­cy to ­that of the ­lead skat­er ­while draft­ing “­close” ­would ­explain part­ly ­that ­there ­were no sig­nif­i­cant dif­fer­enc­es ­between draft­ing at D1 and D2. ­These ­results sug­gest ­that the draft­ing tech­nique ­should be empha­sized in train­ing, espe­cial­ly in non-­skilled skat­ers at ­high veloc­ities and ­when cor­ner­ing.