The purpose of this study was to assess the reliability of measuring voluntary isometric strength, evoked isometric twitch properties (peak torque, time to peak torque, half-relaxation time), M-wave amplitude, and passive tension in very old adults (73-92 years). Five male and 5 female subjects were tested on two different test occasions that were 1 week apart. Using the intraclass correlation coefficient (ICC) method, the mean reliability coefficient of all measurements on the dorsiflexor (DF) and plantar flexor (PF) muscle groups was .91 ± .05. Similar ICC values were found for DF and PF muscles (.92 ± .04 and .90 ± .05, respectively). Resting PF half-relaxation time was the least reliable measure, with an ICC value of .80, while maximum voluntary strength was the most reliable with ICC values of .98 for DF and .97 for PF. The variation ranged from 0.2 to 12.3%. It was concluded that ankle muscle function (both voluntary and evoked) can be reliably assessed in this very old age group.
Karen J. Winegard and Audrey L. Hicks are with the Department of Kinesiology, McMaster University, 1280 Main St. West, Hamilton, ON, Canada L8S 4K1. Anthony A. Vandervoort is with the Department of Physical Therapy, University of Western Ontario, Elbourne College. London. ON N6G 1HI.