Blood Flow Restriction Parameters and Lower Limb Function in Older Adults With Dynapenia

The Effects of Blood Flow Restriction Training Parameters on Lower Limb Muscle Function in Elderly Adults With Dynapenia: Mechanism and Intervention Outcomes

The objective of the first year is to collect limb occlusion pressure (LOP) measurements in older adults with varying levels of muscle health, which will serve as foundational data for subsequent investigations on blood flow restriction (BFR) combined with resistance training in individuals with dynapenia. This phase aims to examine LOP values and their potential influencing factors, including demographic and physiological characteristics such as age, height, body weight, blood pressure, waist circumference, body fat percentage, medical history of chronic diseases, and habitual physical activity. Muscle-related assessments will include skeletal muscle mass, thigh and calf circumference, handgrip strength, and lower limb muscle strength. Functional performance will be evaluated using the five-times sit-to-stand test and the SARC-F questionnaire for sarcopenia risk screening. LOP of the lower limbs will be measured using a BFR cuff system combined with a laboratory-developed blood flow detection device. The study will further investigate whether LOP values are associated with the aforementioned factors.

The objective of the second year is to utilize high-density surface electromyography (dEMG) to analyze the electrophysiological characteristics of muscle contraction in individuals with sarcopenia under varying BFR pressures and resistance intensities. This includes examining motor unit recruitment patterns and recruitment thresholds, with the goal of identifying effective and appropriate BFR exercise parameters for this population.

The objective of the third year is to investigate the effects of lower limb BFR combined with resistance training on functional performance in individuals with dynapenia. Building upon the findings from the first year, this phase will implement BFR resistance training interventions and evaluate both short-term and long-term effects. Through an experimental design, the study will assess changes in body composition, muscle strength, and functional performance following a four-month intervention, along with a three-month follow-up period, to determine whether participants can improve to a healthy status and maintain these improvements over time.

Inclusion Criteria

• Aged 55 years and older.
• No regular physical activity within the past three months, defined as exercising no more than twice per week.
• No cognitive impairment and able to follow exercise and assessment instructions.

Exclusion Criteria

• Have contraindications to exercise, such as severe musculoskeletal problems, osteoporosis, deep vein thrombosis, or coagulation disorders.
• Have comorbid conditions that are severe or end-stage, such as stroke diagnosed by a neurologist, diabetes with severe complications (e.g., retinopathy), or cardiovascular disease including heart failure, coronary ischemia, or arrhythmia.
• Have high-risk factors for exercise, such as uncontrolled hypertension (systolic blood pressure >160 mmHg or diastolic blood pressure >100 mmHg), angina or chest tightness during exercise, or deep vein thrombosis.
• Have a history of hematologic disorders or are currently taking blood-related medications, such as hormones or anticoagulants.
• Are expected to move out of the local community within three months.