effect of sequencing on outcome measures

Conditions: Muscle Weakness

Summary: this pilot study will examine the effect of testing order on test outcomes for measures of strength, dynamic balance, and movement quality. each participant will perform a baseline test, then will perform the 6 iterations of the testing sequence.

this study employs a repeated measures design, with each participant tested multiple times in combinations of 1) the isokinetic torque test, 2) the y-balance test/firefighter-specific functional-balance test, and 3) the forward-step-down test. the investigators will conduct a total of seven testing sessions, including a control session (informed consent, familiarization with outcome measures, and control data collection) and the following six different patterns: 1-2-3, 1-3-2, 2-1-3, 2-3-1, 3-1-2, and 3-2-1. the order of the sessions will be randomized and counterbalanced to prevent bias effects. the control session will be performed in the following order: (1) forward-step-down test, (2a) firefighter specific functional balance test, (2b) y-balance test, (3) isokinetic tests (hip then knee). participants will be asked to avoid exercise or vigorous physical activity for the 24 hours prior to any testing session to minimize the effects of non-test-related fatigue on the study outcomes. pre and post-test fatigue will be measured with the rating of fatigue (rof) scale. pre-and post-test exertion will be measured with the borg rating of perceived exertion (rpe) scale (attached). heartrate will be measured and recorded at each scale rating point. upon arrival for the control session, participants will have their height measured using a stadiometer and their weight recorded. this will be followed by the performance of the initial 1-2-3 pattern. the time needed for the participant to perform each test will be recorded and subsequent performances of that test will be carried out in this time frame. for visits two through seven, participants will be weighed again upon arrival and perform one of the six patterns. sessions two to seven will be separated by at least one day to minimize the influence of fatigue. each session will include isokinetic torque measurements of the hip abductors and adductors, knee flexors and extensors, the y-balance test, the firefighter-specific functional-balance test, and the forward-step-down test. the dominant leg will be used for unilateral tests, as determined by the leg used to kick a ball. the order of outcome measures will be randomized for each participant to minimize the effects of fatigue and recovery. five minutes of warm-up on a stationary bike or walking will be performed to start each exercise session. five minutes of rest and instruction will be provided between each outcome measure. five minutes of rest will be given between isokinetic tests (hip abduction to adduction) to allow for machine set-up and instructions. one minute of rest will be given between each isokinetic speed, with three speeds tested for the hip (30°, 60°, and 120° per second) and knee (60°, 180°, and 300° per second) muscles.

Eligibility criteria:
inclusion criteria: * healthy adult by physical activity readiness questionnaire+ screening process exclusion criteria: * lower extremity or spine injury in past 6 months * vestibular disorder * known pregnancy * inability to complete data collection

Keywords: strength dynamic balance movement quality injury prevention