title: Symptoms and quadriceps fatigability after walking and cycling in chronic obstructive pulmonary disease.
abstract: Patients with chronic obstructive pulmonary disease (COPD) may stop cycling due to leg effort rather than breathlessness. However, cycling is not relevant to many patients, although walking may be more familiar. A total of 84 patients with COPD were asked to name the predominant symptom limiting incremental shuttle walking, endurance shuttle walking, incremental cycle ergometry, and endurance cycle ergometry, performed to exhaustion on four separate days. Furthermore, quadriceps fatigability was evaluated in 12 patients by measuring unpotentiated and potentiated twitch quadriceps tensions before and 30 minutes after incremental walking and cycling. Breathlessness alone was a more commonly cited limiting symptom after incremental walking compared with incremental cycling (81 vs. 34%; p < 0.001) and after endurance walking compared with endurance cycling (75 vs. 29%; p < 0.001). In addition, there was no significant change in mean pre- and postwalking twitch quadriceps tensions. However, cycling produced a significant reduction (unpotentiated 7.42 +/- 2.22 vs. 6.48 +/- 2.09 kg [p < 0.001]; potentiated 10.19 +/- 3.99 vs. 8.45 +/- 3.18 kg [p < 0.001]). Pre- to postexercise changes were significantly greater during cycling compared with walking (unpotentiated p = 0.01; potentiated p = 0.003). Leg effort is an infrequent symptom after walking in COPD, and low frequency fatigue of the quadriceps is an infrequent feature of incremental walking.
authors.affiliation: Respiratory Muscle Laboratory, Guy's King's and St Thomas' School of Medicine, King's College Hospital, Bessemer Road, London SE5 9PJ UK. William.man@kcl.ac.uk
authors.forename: William D-C
authors.initials: WD
authors.lastname: Man
authors.forename: Mohamed G G
authors.initials: MG
authors.lastname: Soliman
authors.forename: Johanne
authors.initials: J
authors.lastname: Gearing
authors.forename: Sheena G
authors.initials: SG
authors.lastname: Radford
authors.forename: Gerrard F
authors.initials: GF
authors.lastname: Rafferty
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Gray
authors.forename: Michael I
authors.initials: MI
authors.lastname: Polkey
authors.forename: John
authors.initials: J
authors.lastname: Moxham
mesh_terms: D000368:Aged; D001642:Bicycling / Q000502:physiology*; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000503:physiopathology*; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000503:physiopathology*; D012720:Severity of Illness Index; D013848:Thigh / Q000503:physiopathology; D013997:Time Factors; D016138:Walking / Q000502:physiology*