Affiliations: School of Health Sciences, Faculty of Health, University of Newcastle, NSW, Australia
Note: [] Corresponding author: Dr Carole James, School of Health Sciences, University of Newcastle, University Drive, Callaghan, NSW 2308, Australia. Tel.: +61 249216632; Fax: +61 249217053; E-mail: Carole.James@newcastle.edu.au
Abstract: BACKGROUND: The safe maximal lift for a person is often determined
during a functional capacity evaluation. This determination is based upon
observation of unsafe lifting techniques, however there is limited information
on specific kinematic changes that assist a therapist's clinical reasoning and
determination of the safe maximal lift. OBJECTIVE: To evaluate any change in kinematics between safe minimum
and safe maximum floor-to-bench lifts during the WorkHab Functional Capacity
Evaluation. METHOD: Twenty-eight healthy participants (age range 18–22 years) were
digitally recorded completing the evaluation. Lumbar spine, hip, knee and ankle
joint angles were measured using Dartfish Pro-suite software at the beginning
(0/3), one third (1/3), two thirds (2/3) and end (3/3) of the lift in
descending and ascending phases. Paired t-tests were used to compare joint
angles at each point of minimum and safe maximum lifts. RESULTS: Significant changes in joint angles occurred lifting safe
maximum weight compared to minimum weight. The lumbar spine was in greater
flexion [4.9, 95% CI 2.1:7.7, p=0.001]; the knee joint was in less flexion
descending [−4.5, 95% CI −8.1: −0.8, p=0.004 (3/3)] and
ascending [−9.7, 95% CI −18.3: −1.16, p=0.027 (0/3)] and hip
flexion increased at all points of the ascending phase (p⩽ 0.021). The
ankle joint was in less dorsiflexion while descending [8.0, 95% CI 3.4:12.7,
p=0.001(2/3); 6.7, 95% CI 4.4:9.0, p⩽0.001(3/3)] and ascending [8.9, 95% CI
6.24:11.6, p=0.001(0/3); 3.6, 95% CI 1.5:5.7, p⩽0.001(3/3)]. CONCLUSIONS: This study provides insight into kinematic changes and
support observations made by the WorkHab assessor in determining a safe maximal
lift during floor-to-bench lifts.
Keywords: Kinematics, lifting, work capacity evaluation
