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Background: This pilot trial explores the feasibility of measuring muscle contractile properties in patients with cancer, effects of exercise during chemotherapy on muscle contractile properties and the association between changes in contractile muscle properties and perceived fatigue., Method: Patients who received (neo)adjuvant chemotherapy for breast or colon cancer were randomized to a 9-12 week exercise intervention or a waitlist-control group. At baseline and follow-up, we measured knee extensor strength using maximal voluntary contraction (MVC), contractile muscle properties of the quadriceps muscle using electrical stimulation, and perceived fatigue using the Multidimensional Fatigue Inventory. Feasibility was assessed by the proportion of patients who successfully completed measurements of contractile muscle properties. Exercise effects on muscle contractile properties were explored using linear regression analyses. Between-group differences >10% were considered potentially relevant. Pearson correlation (r p ) of changes in contractile muscle properties and changes in perceived fatigue was calculated., Results: Twenty two of 30 patients completed baseline and follow-up assessments. Measurements of contractile properties were feasible except for muscle fatigability. We found a potentially relevant between-group difference in the rate of force development favoring the intervention group (1192 N/s, 95% CI = -335; 2739). Change in rate of force development was negatively correlated with change in perceived general (r p  = -0.54, P = .04) and physical (r p  = -0.59, P = .02) fatigue., Conclusion: Chemotherapy induces a decrease in the rate of force development, which may reflect a larger loss in type II muscle fibers. This may be attenuated with (resistance) exercise. The increase in the rate of force development was related to a decrease in perceived fatigue., (© 2020 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.)

Objectives: We aimed to investigate accelerometer output corresponding to physical activity intensity cut-points based on percentage of peak oxygen consumption (%VO 2 peak) and Metabolic Equivalent of Task (MET) value in women treated for breast cancer., Design: Laboratory study., Methods: Fifty female patients shortly after completion of treatment for breast cancer were included. VO 2 peak was determined during a cardiopulmonary exercise test. Subsequently, patients performed ten activities with different intensities while wearing an accelerometer on the right hip and a mobile oxycon to assess oxygen consumption. We studied the relationship between energy expenditure (expressed as %VO 2 peak and MET-value) and accelerometer output (in counts per minute (cpm)) with linear regression analyses. We determined accelerometer output corresponding to physical activity intensity cut-points (40% and 60%VO 2 peak; 3 and 6 MET) using regression equations., Results: VO 2 peak was 22.4mL/kg/min (SD 5.2) and resting metabolic rate was 3.1mL/kg/min (SD 0.6). Accelerometer output corresponding to the cut-points for moderate (40% VO 2 peak) and vigorous intensity (60% VO 2 peak) were 1123 and 1911, respectively. The analyses based on MET-values resulted in accelerometer output of 1189cpm for the moderate (3 MET) and 2768 cpm for the vigorous intensity cut-point (6 MET)., Conclusions: Accelerometer outputs for moderate and vigorous intensity physical activity were lower than commonly used cut-points (i.e. 1952 and 5724 cpm), irrespective of the method used to express energy expenditure (%VO 2 peak versus MET-value). Thus, categorizing physical activity intensities based on general-population cut-points, may underestimate physical activity intensities for women treated for breast cancer., (Copyright © 2019 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

Purpose:Delivery of exercise interventions to patients with early-stage breast cancer undergoing chemotherapy requires complex clinical decisions. The purpose of this study was to develop a framework to support clinical decisions for tailoring exercise interventions to common comorbidities and cancer treatment-induced adverse effects. Method:Tailored exercise prescriptions were developed in four steps, following the i3-S strategy. All steps were based on current best available evidence, complemented with expert opinions. First, common comorbidities and treatment-induced adverse effects were identified. In the subsequent steps, contra-indications and restrictions for exercise were described, along with possible exercise adaptations. In the final step, the obtained information was synthesized into a framework. Results:Prevalent comorbidities were hypertension, heart disease, diabetes mellitus, (osteo)arthritis, chronic obstructive pulmonary disease, and obesity. Adverse effects included conditions induced by pretreatment (e.g., lymphedema as a result of surgery) or by chemotherapy (e.g., reduced blood cell counts). Adaptations to the recommended exercise program were related to exercise tolerance, safety, and hygiene. A framework was proposed to guide clinical decisions during the exercise intervention. Conclusion:Comorbidities and adverse effects of breast cancer treatment require exercise adaptations. The proposed framework provides guidance on tailored exercise prescriptions in patients with breast cancer undergoing chemotherapy.Implications for RehabilitationExercise is recommended for patients with breast cancer undergoing chemotherapy, but requires complex clinical decisions of the health professional.We identified the most important comorbidities and adverse effects of breast cancer treatment, and the resultant contra-indications and restrictions to exercise.We incorporated these findings into a clinical decision framework that provides suggestions for exercise adaptations in patients with breast cancer undergoing chemotherapy. [ABSTRACT FROM PUBLISHER]