Background: Ambulatory patients with Amyotrophic Lateral Sclerosis (ALS) show a decreased aerobic capacity which may hamper the ability to perform activities of daily living. A standardized measure, however, for assessing aerobic capacity in patients with ALS during the disease course, is lacking.
Objective: To examine the feasibility of the Åstrand-Ryhming (ÅR) test protocol longitudinally in ambulatory patients with amyotrophic lateral sclerosis (ALS).
Methods: Seven ambulatory male patients with spinal ALS onset were assessed at baseline and at 4, 7 and 10 months' follow-up. Feasibility of the ÅR test protocol was analysed using percentage of: a) completed ÅR tests; b) achieved steady states; and c) predefined heart rates.
Results: Test completion decreased from 7/7 at baseline to 10/21 at follow-up due to ALS-related symptoms as fatigue, muscle weakness and cramps. Steady states and predefined heart rates were achieved in 12/17 and 17/17 of the completed tests, respectively. Overall, the feasibility of the ÅR test protocol declines from 5/7 at baseline to 7/21 at follow-up.
Conclusions: The results suggest that changes in aerobic capacity in ambulatory patients with ALS could not be successfully monitored due to a diminished feasibility of the ÅR test protocol.
Keywords: Amyotrophic Lateral Sclerosis; aerobic capacity; exercise test; outcome measure; physical fitness.