ABSTRACT
BACKGROUND: There is a growing number of breast cancer survivors from improved cancer treatments. However, treatments often impair upper limb function, specifically range of motion and strength, reducing quality of life and function. The primary purpose of this study was to quantify differences in strength and range of motion following treatment. The secondary purpose aimed to measure the activation of each upper limb muscle in the completion of tasks. METHODS: 29 breast cancer survivors were categorized into two groups based on time-since-treatment: 1) up to 1-year post-treatment, and 2) 1 to 2 years post-treatment. Participants completed maximal strength and range of motion tasks. During trials eight muscles were monitored bilaterally. Maximal force output was taken during strength trials, and kinematics were monitored during range of motion trials. A 2 by 2 mixed ANOVA (limb (affected, unaffected) x time-since-treatment) examined interaction and main effects of these factors on task peak force, angle and mean activation. FINDINGS: Time-since-treatment influenced strength (flexion, extension, internal and external rotation) and range of motion (flexion, scapular abduction), wherein the group further from treatment had 11.5-15.5° less range of motion and 27.7-43.6 N less force production. A main effect of time-since-treatment influenced muscular behaviours during both tasks, where activation was higher in the group 1-2 years from treatment. INTERPRETATION: Effects of treatment may manifest in a delayed manner whereby strength and range of motion are reduced in breast cancer survivors to a greater extent in those who are past 1 year of treatment cessation.
