Aims
Eccentric exercise (ECC) is a potentially effective exercise therapy modality during cancer, due to its effectiveness at improving muscle mass and architecture, body composition, and metabolic markers which are often impaired during cancer disease and treatments, at lower efforts and cardiovascular demands compared to conventional exercises (1-3). To examine the available evidence, we conducted a scoping literature review.
Methods
Medline and Scopus databases were searched for published studies included until August 2023. Search terms included keywords and various combinations related to ECC, cancer disease, symptoms, and therapies. Peer-reviewed journal articles were included if they included humans or animals with cancer, examined the effects of different forms of ECC, were in English, and were not reviews. Secondary searches involved reference lists of eligible articles as well as systematic reviews and meta-analyses assessing resistance exercise interventions during cancer.
Results
Animal (n=3) and human (n=4) studies were found. Animal studies (ApcMin/+ and Colon-26 mice models) concluded that ECC (through electrical stimulation) is an effective strategy to ameliorate muscle wasting during cancer cachexia.
Of the 4 human studies (108 people; 46 females), 2 included specific diseases (prostate or head-and-neck cancer) whereas 2 included multiple types (lymphoma, breast, prostate, lung, and colorectal cancers). Cancer treatments were either local (surgery ± radiotherapy), systemic (chemo or hormone therapies), or a combination of the two. Forms of ECC included eccentric stepping (n=3) and eccentric-overloaded squat exercises (n=1).
ECC was safe and well tolerated (n=4), significantly increased strength and function (n=4), successfully increased muscle mass even during androgen-deprivation therapy or chemotherapy (n=2), and caused clinical-relevant reductions in cancer-related fatigue (n=2).
Conclusions
ECC is a safe non-pharmacological intervention during cancer for symptom and treatment side-effect management, with a small number of studies showing significant improvements in muscle mass, strength, and cancer-related fatigue. More studies are required, to investigate different forms of ECC, stratified to specific cancer types and therapies.