Objective: Weakness of peripheral muscles may contribute to reduced exercise capacity in patients with lung cancer. The leg extensor power rig (leprig) provides one way of measuring peripheral muscle strength. Tolerability and repeatability has not previously been examined in patients with lung cancer.
Method: 16 patients with lung cancer, mean age 63 and ECOG performance status of 0 2, have been recruited. The leprig consists of an adjustable seat facing pedals that are connected through a chain to a flywheel. An optoswitch detects the maximal speed of the flywheel after a pedal push and is used to calculate power. After a practice push verbal encouragement is given to obtain a maximal effort with repeated attempts until no further improvement is shown. Two tests were carried out on consecutive days. Repeatability was assessed as the standard deviation of the difference between tests (SDdiff) and the intraclass correlation coefficient (ICCC; values<0.6 indicate poor repeatability). Results All patients completed the test and found the leprig tolerable and acceptable. Patients reached a maximal value within 10 attempts. Mean power, standard deviation of the difference between tests and ICCC was 97.6W, 19.1 and 0.93 respectively. Conclusion The leprig appears an acceptable and tolerable method of assessing leg muscle strength in patients with lung cancer. Using power as the main outcome, a comparative between day study would require 13 patients in each group to reliably detect a change of 25% (power=90%).