Physical Function Tests (PFTs) were introduced in Visit 5 (1988) and included in each subsequent RBS clinic visit through Visit 11 (2009). Participants completed performance-based measurements of lower extremity physical function tasks and grip strength. The specific tests administered at each visit are shown in here. All PFTs in RBS were administered by trained, certified personnel, with consistent administration and scoring across visits.
Grip strength was measured using a handheld dynamometer in each hand twice, and the maximum strength (kg) of each hand was recorded. Participants’ ability to complete a single chair stand without the use of their arms was recorded. They were asked to perform five chair stands without their arms and the time to completion was recorded in seconds. Subjects ambulated for an examiner and were assessed with respect to limp, shuffle, arm swing and speed. Tandem (heel to toe) walking was categorized. Timed “Up and Go” Test (3 meter) was performed and two trials were timed (sec). Walking speed was measured at usual pace over a 6-m course as seconds and number of steps. The time (sec) to complete a 20-cm wide narrow walking course over 6 m was recorded and used to determine dynamic balance. One leg stand was performed using each leg and with eyes open and closed. Each condition was timed in order to reach 30 seconds, allowing 5 trials each. Leg extension power (watts) was measured on the Nottingham Power Rig (University of Nottingham, Nottingham, England) with up to five trials per leg.