Cardiorespiratory Changes During Prolonged Downhill Versus Uphill Treadmill Exercise.
Fiche publication
Date publication
décembre 2019
Journal
International journal of sports medicine
Auteurs
Membres identifiés du Cancéropôle Est :
Pr LEPERS Romuald
Tous les auteurs :
Garnier Y, Lepers R, Assadi H, Paizis C
Lien Pubmed
Résumé
Oxygen uptake (V̇O), heart rate (HR), energy cost (E) and oxygen pulse are lower during downhill compared to level or uphill locomotion. However, a change in oxygen pulse and E during prolonged grade exercise is not well documented. This study investigated changes in cardiorespiratory responses and E during 45-min grade exercises. Nine male healthy volunteers randomly ran at 75% HR reserve during 45-min exercise in a level (+1%), uphill (+15%) or downhill (-15%) condition. V̇O , minute ventilation (V̇ ) and end-tidal carbon dioxide (PCO) were recorded continuously with 5-min averaging between the 10 and 15 min (T1) and 40 and 45 min (T2). For a similar HR (157±3 bpm), V̇O , V̇ , and PCO were lower during downhill compared to level and uphill conditions (p<0.01). V̇O and V̇ decreased similarly from T1 to T2 for all conditions (all p<0.01), while PCO decreased only for the downhill condition (p<0.001). Uphill exercise required greater E compared to level and downhill exercises. E decreased only during the uphill condition between T1 and T2 (p<0.01). The lowest V̇O and E during downhill exercise compared to uphill and level exercises suggests the involvement of passive elastic structures in force production during downhill. The lower cardiorespiratory response and the reduction in PCO during downhill running exercise, while E remained constant, suggests an overdrive ventilation pattern likely due to a greater stimulation of efferent neural factors.
Référence
Int J Sports Med. 2019 Dec 2;: