Resistance Exercise During Cancer Rehabilitation

Abstract

Resistance exercise is an increasingly important component of contemporary cancer rehabilitation. By applying progressive external or body-weight loading to major muscle groups, resistance training can counteract cancer-related muscle wasting, treatment-associated deconditioning, fatigue, functional decline, and loss of independence. Its benefits extend beyond muscle hypertrophy and include improved strength, physical performance, bone health, insulin sensitivity, psychosocial well-being, and tolerance of daily activities. Evidence from exercise oncology research indicates that appropriately prescribed resistance exercise is generally safe for many people receiving or recovering from cancer treatment, provided that exercise selection, intensity, monitoring, and progression are individualized. Clinical decision-making must account for tumor type and stage, treatment modality, hematologic status, cardiopulmonary function, bone involvement, neuropathy, lymphedema risk, surgical restrictions, nutritional status, and patient preferences. This review summarizes the disease burden addressed by resistance exercise, relevant pathophysiological mechanisms, clinical assessment, management principles, emerging research, and guideline-based recommendations for healthcare professionals.

Introduction

Cancer rehabilitation aims to prevent or reduce impairments caused by malignancy and its treatment while supporting participation in meaningful physical, social, and occupational activities. Although aerobic exercise has traditionally received substantial attention, resistance exercise is essential because cancer and anticancer therapies frequently compromise skeletal muscle quantity, quality, and function. Surgery, chemotherapy, radiotherapy, endocrine therapy, corticosteroids, immunotherapy, prolonged hospitalization, and reduced physical activity may collectively produce weakness and impaired mobility. Resistance exercise provides a structured method for restoring force production and preserving functional reserve throughout the cancer continuum, including active treatment, survivorship, and palliative care.

The therapeutic objective is not simply to increase muscle size. Clinically relevant goals include improving the ability to rise from a chair, climb stairs, carry objects, maintain balance, tolerate treatment, and remain independent. A medically supervised program can be adapted to curative, rehabilitative, or palliative priorities. The prescription should be viewed as a clinical intervention requiring screening, dose adjustment, outcome measurement, and coordination with oncology, rehabilitation, nursing, nutrition, and allied health teams.

Epidemiology / Disease Burden

Functional impairment is common among people with cancer, although prevalence varies by tumor type, disease stage, age, treatment exposure, comorbidity, and method of assessment. Declines in muscle strength and physical performance may occur even when body weight is stable. In advanced disease, cancer cachexia can cause involuntary weight loss, reduced appetite, systemic inflammation, and progressive loss of skeletal muscle. In early-stage disease, treatment-related inactivity and fatigue may still result in clinically meaningful weakness.

Reduced muscle function is associated with falls, hospitalization, treatment interruption, poorer tolerance of activities of daily living, and diminished health-related quality of life. Older adults and individuals with pre-existing sarcopenia, cardiopulmonary disease, obesity with low muscle quality, or multiple comorbidities may be particularly vulnerable. Because routine oncology visits may focus primarily on tumor response and adverse effects, functional decline can remain underrecognized unless clinicians systematically ask about mobility, work capacity, falls, and difficulty performing daily tasks.

Pathophysiology

Cancer-related muscle dysfunction reflects interacting metabolic, inflammatory, neurologic, vascular, and behavioral mechanisms. Proinflammatory mediators can increase proteolysis, impair anabolic signaling, alter mitochondrial function, and reduce muscle protein synthesis. Reduced food intake and inadequate protein availability may intensify negative nitrogen balance. Treatment-related nausea, mucositis, gastrointestinal toxicity, pain, and endocrine changes can further compromise nutritional and muscular status.

Resistance exercise stimulates mechanotransduction pathways that promote muscle protein synthesis, neuromuscular recruitment, tendon loading, and remodeling of connective tissue. Repeated training may improve motor-unit activation and coordination before substantial hypertrophy occurs, which explains why functional gains can appear relatively early. Resistance exercise can also support glucose regulation, vascular health, bone loading, and confidence in movement. However, exercise does not reverse all forms of cachexia, and severe systemic illness may limit anabolic responsiveness. Training should therefore complement, rather than replace, nutritional management, symptom control, anticancer treatment, and palliative care.

Risk Factors

Factors that increase the risk of exercise-related complications include unstable cardiovascular disease, uncontrolled infection, severe anemia or thrombocytopenia, significant electrolyte abnormalities, symptomatic bone metastases, pathologic fracture risk, uncontrolled pain, severe dizziness, acute postoperative restrictions, and clinically important cardiopulmonary limitation. Peripheral neuropathy may impair proprioception and increase fall risk, while treatment-related cardiotoxicity can reduce exercise tolerance. Patients with lymphedema or a high risk of lymphatic complications require individualized loading and monitoring rather than automatic exclusion from resistance training.

Additional considerations include central venous access devices, ostomies, wounds, severe fatigue, cognitive impairment, malnutrition, diabetes, osteoporosis, and medications that affect blood pressure or heart rate. The presence of metastatic disease does not automatically prohibit exercise, but loading strategies may need to avoid vulnerable skeletal sites and high-impact or torsional movements. Communication with the treating oncology team is essential when disease burden, laboratory values, or treatment status creates uncertainty.

Clinical Features

Patients who may benefit from referral often report difficulty lifting, carrying, standing, climbing stairs, walking longer distances, or completing household and occupational tasks. Observable findings may include reduced grip strength, slow chair-rise performance, abnormal gait, impaired balance, muscle wasting, reduced range of motion, and dependence on assistance for daily activities. Fatigue is common but should not be presumed to be the sole cause of poor function. Pain, depression, sleep disturbance, anemia, endocrine dysfunction, cardiopulmonary disease, and medication effects may coexist and require specific evaluation.

Clinicians should characterize symptom onset, treatment timing, functional trajectory, falls, exercise history, nutritional intake, and patient-defined goals. The distinction between exertional fatigue that improves with graded activity and symptoms suggesting acute disease or treatment toxicity is clinically important. Exercise should be paused and medically reviewed when new chest pain, unexplained syncope, severe breathlessness, fever, acute neurologic symptoms, or rapidly worsening bone pain occurs.

Diagnosis

Assessment should combine medical screening with objective functional measures. Relevant investigations may include complete blood count, metabolic testing, nutritional assessment, cardiac evaluation, and imaging review when bone disease or structural risk is suspected. Body composition can be evaluated using computed tomography-derived muscle area, dual-energy X-ray absorptiometry, bioimpedance, or anthropometric methods, recognizing that each approach has limitations.

Common functional outcomes include handgrip strength, the five-times sit-to-stand test, timed up-and-go, gait speed, six-minute walk testing, and patient-reported physical function. The choice of test should reflect safety, disease burden, and clinical purpose. Baseline assessment establishes an individualized starting point and allows clinicians to distinguish training response from disease progression or treatment toxicity. Reassessment at planned intervals can guide progression and identify deterioration requiring medical review.

Treatment & Management

Resistance exercise should begin with a clear therapeutic objective and an appropriately conservative dose. Programs may use machines, free weights, resistance bands, cable systems, body-weight movements, or functional tasks such as sit-to-stand exercises. Initial sessions commonly emphasize technique, breathing, joint alignment, controlled movement, and tolerance rather than maximal loading. Large muscle groups should be addressed when clinically feasible, with special attention to lower-limb strength because it strongly influences transfers, gait, and fall risk.

Intensity and volume should be individualized according to treatment phase, baseline capacity, symptoms, and recovery between sessions. A practical progression may increase repetitions, resistance, sets, movement complexity, or training frequency one variable at a time. Patients should avoid breath holding and excessive straining, particularly when cardiovascular or surgical considerations are present. Adequate recovery, hydration, sleep, and protein intake support adaptation. On days of substantial treatment toxicity, the session may be shortened, simplified, or replaced by mobility and breathing activities.

Supervised training is preferable for patients with substantial weakness, balance impairment, bone metastases, complex postoperative restrictions, severe neuropathy, or limited exercise experience. Home-based programs can be effective when safety instructions, monitoring procedures, and communication pathways are clearly established. Clinicians should document adverse symptoms, treatment interruptions, functional outcomes, and the patient’s perceived exertion. Resistance exercise is most effective when integrated with aerobic conditioning, flexibility, balance training, psychosocial support, and nutritional care rather than delivered in isolation.

Recent Advances / Emerging Therapies

Current research is examining how resistance exercise can be personalized using muscle imaging, wearable activity monitoring, remote supervision, digital symptom tracking, and biomarker-informed risk stratification. Hybrid programs combining in-person rehabilitation with telehealth may improve access for patients who live far from specialist services or who experience fluctuating treatment schedules. Investigators are also studying exercise during neoadjuvant therapy, hematopoietic transplantation, immunotherapy, and advanced cancer, populations historically underrepresented in exercise trials.

Emerging work emphasizes precision rehabilitation. Training responses may be influenced by tumor biology, inflammation, nutritional status, hormonal environment, medication exposure, and baseline muscle quality. Research is needed to determine which exercise doses best preserve function during cachexia, how resistance training interacts with novel anticancer agents, and which outcomes most accurately reflect meaningful benefit. Exercise oncology should also address disparities related to cost, transportation, disability, language, digital access, and culturally appropriate care.

Guideline Recommendations

Major oncology and exercise medicine organizations generally support individualized physical activity for people with cancer, provided that medical safety and treatment-specific precautions are addressed. Resistance exercise is commonly recommended on a regular basis, often at least two nonconsecutive days per week when tolerated, with gradual progression and inclusion of major muscle groups. These recommendations are principles rather than rigid prescriptions; a patient receiving intensive therapy may appropriately begin with brief, low-load sessions, while a medically stable survivor may progress toward conventional strength-training volumes.

Before initiation, clinicians should screen for contraindications, review treatment-related complications, and establish emergency procedures. Exercise professionals working with oncology populations should understand cancer therapies, symptom patterns, surgical precautions, infection-control requirements, bone stability, and signs requiring referral. Blood counts and other laboratory results should be interpreted in clinical context, and institutional policies should guide exercise during periods of immunosuppression or acute treatment toxicity. Shared decision-making is central: the program should reflect patient goals, preferences, resources, cultural context, and acceptable levels of exertion.

Conclusion

Resistance exercise is a clinically valuable intervention in cancer rehabilitation because it targets the muscle weakness, functional loss, and reduced independence that commonly accompany malignancy and its treatment. Its mechanisms include improved neuromuscular activation, preservation of muscle protein balance, enhanced task-specific capacity, and beneficial effects on bone, metabolic, and psychosocial health. Safe implementation requires structured screening, individualized dosing, careful progression, symptom monitoring, and collaboration with the oncology team. When integrated with medical treatment, nutrition, aerobic conditioning, and supportive care, resistance exercise can help patients maintain function and pursue personally meaningful goals across the cancer trajectory. Future research should refine precision prescriptions, expand evidence in advanced and medically complex populations, and improve equitable access to qualified cancer rehabilitation services.