title: Energy cost of spontaneous walking in Parkinson's disease patients.
abstract: In healthy subjects, comfortable walking minimizes the energy cost (E (c)) of locomotion. In Parkinson's disease (PD) patients walking is slower than in healthy subjects: this may increase E (c). Our aims were to analyze gait and E (c) in PD patients during walking, particularly at self-selected speed, and the possible pathological, mechanical, and cardiorespiratory limitations. Fourteen mild-to-moderate PD and 14 control subjects were enrolled. Subjects underwent 5-min walking tests at two speeds: self-selected and as-fast-as-possible speeds. Cardiopulmonary and gait parameters (heart rate, ventilation, gas exchanges, step count) were recorded. Velocity was reduced in PD compared to control subjects at both speeds (P < 0.05), and PD patients had shorter strides (P < 0.05) at both speeds and reduced cadence (P = 0.01) at fastest speed. No significant difference was found in E (c) at self-selected (0.12 ± 0.04 versus 0.11 ± 0.02 mLO(2) kg(-1) m(-1) in PD and control subjects, respectively) and maximal (0.14 ± 0.03 versus 0.15 ± 0.02 mLO(2) kg(-1) m(-1) in PD and control subjects, respectively) speed. However, the E (c) increment from self-selected to fastest velocity was significantly lower (P = 0.02) in PD patients. PD patients failed to walk at a self-selected speed, which minimizes the E (c). This could be mainly due to the inability to develop a wider stride. Cardiorespiratory adaptation was not affected, except for the possible reduced cardiac adaptation observed in some (28%) cases. Presumably, rehabilitation procedures that improve flexibility and step length may help maintain walking ability.
authors: Department of Sport, Nutrition and Health Sciences, University of Milan, Via Giuseppe Colombo, 71, 20133 Milan, Italy. martina.maggioni@unimi.it
authors: Martina A
authors: MA
authors: Maggioni
authors: Arsenio
authors: A
authors: Veicsteinas
authors: Susanna
authors: S
authors: Rampichini
authors: Emiliano
authors: E
authors: Cè
authors: Raffaello
authors: R
authors: Nemni
authors: Giulio
authors: G
authors: Riboldazzi
authors: Giampiero
authors: G
authors: Merati
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D016022:Case-Control Studies; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D010300:Parkinson Disease / Q000503:physiopathology*; D012123:Pulmonary Ventilation / Q000502:physiology; D012720:Severity of Illness Index; D016138:Walking / Q000502:physiology*