The Effect of Radiation Therapy and a 12-week Novel Strength Training Intervention on Neuromuscular Function and Fatigability in People Diagnosed with Head & Neck Cancer
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2019-09-13
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Abstract
Treatment for head and neck cancer (HNC) is associated with multiple side-effects and deleterious consequences including reductions in body mass, physical function and health- related quality of life (HRQL). Little is understood about alterations in neuromuscular function and fatigability induced by radiation therapy (RTx). Early evidence suggests strength training is beneficial following treatment for HNC. We hypothesized that exercise prescription could be optimized to promote improvements in muscle strength and mass. This work aimed to investigate the impact of RTx ± chemotherapy on muscle strength, muscle cross-sectional area (CSA) and patient-reported outcomes, and central and peripheral alterations during a whole-body exercise task. Also, we aimed to investigate the feasibility of a 12-week strength training program with the intention of optimizing muscle strength and muscle mass. In the first study, volunteers (n = 10) attended the laboratory before (5 ± 5 days) and after (56 ± 30 days) the completion of anti-cancer treatment. Participants performed a neuromuscular assessment (involving maximal isometric voluntary contractions [MIVC] in the knee extensors and electrical stimulation of the femoral nerve) before and during intermittent cycling to volitional exhaustion. Anthropometrics, self-reported fatigue and HRQL were also assessed. From before to after treatment, MIVC, potentiated twitch, and muscle CSA decreased approximately 18%, 16%, and 20%, respectively. Time to volitional exhaustion was also reduced, and peripheral processes contributed to a reduction in maximal force due to cycling exercise. In the second study, participants (n = 22) were randomized to either an experimental (EXP) strength training intervention involving eccentric overloading and neuromuscular electrical stimulation (n = 11) or a conventional (CON) strength training intervention (n = 11) similar in overall frequency and repetitions. Feasibility outcomes were quantified as rates of accrual, completion, adherence and compliance. Regardless of allocation, 86% of participants completed the intervention and adherence was 88%. From before to after the interventions, muscle strength and muscle CSA in the knee extensors increased ~22% and 18%, respectively. Patient-reported fatigue severity and HRAL also demonstrated clinically relevant improvements. The results of this work suggest that muscle strength and muscle CSA are reduced following treatment for HNC but are regained to a similar extent after 12-weeks of strength training. Also, peripheral fatigue, rather than central fatigue is more pronounced in people affected by HNC following a maximal effort cycling task. Fully supervised strength training programs in survivors of HNC are feasible. These findings offer greater flexibility for future training programs where conventional strength training may not be tolerable.
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Lavigne, C. (2019). The Effect of Radiation Therapy and a 12-week Novel Strength Training Intervention on Neuromuscular Function and Fatigability in People Diagnosed with Head & Neck Cancer (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.