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NCT Number: NCT06746792

Low Load, High Gains: Blood Flow Restriction's Impact on Quadriceps Adaptations

Low-load resistance exercise with blood flow restriction (BFR-RE) presents a compelling alternative to high-load resistance exercise (HL-RE), particularly in scenarios where high loads are not feasible due to various limitations. Blood flow restriction exercise restricts blood flow to the working muscle, creating a state of ischemia. A significant advantage of BFR-RE lies in its capacity to stimulate muscle hypertrophy and strength adaptations using light external loads (20-30% 1RM), comparable to those achieved with high-load (HL) training programs that employ 70-85% 1RM As a result, BFR training has been increasingly adopted in both athletic performance and rehabilitation settings over the past few decades. Quadriceps strength and power are essential factors in both the advancement of athletic performance and the successful return to unrestricted sporting activity following injury. The findings of Culvenor et al.'s review strongly suggest that weakened quadriceps strength is a significant risk factor for symptomatic and functional decline in the knee during both activities of daily living and sport-recreational activities. Numerous electromyographic (EMG) findings suggest that single-joint and multijoint exercises elicit varying muscle activation patterns. For instance, single-joint exercises targeting the quadriceps, such as leg extensions, demonstrate higher EMG amplitudes compared to multijoint lower-extremity exercises like leg presses and squats. Resistance training, characterized by the application of high mechanical tension, remains the cornerstone for promoting muscle hypertrophy, So, research suggests that higher training intensities are associated with greater hypertrophy, up to a certain point. While both light and heavy loads have been shown to elicit similar muscle growth when sets are taken to failure. Studies have reported that high-repetition training with light loads leads to greater central fatigue. Existing literature comparing the effects of BFR-RE and HL-RE primarily focuses on the some quadriceps and hamstring muscle group and its associated exercises. However, none of these studies employed a training protocol in which sets were taken to or near failure.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Key information

Conditions

Healthy Individuals Hypertrophy Pathological Conditions, Anatomical Pathological Conditions, Signs and Symptoms

Age range

18 year–25 year

Sex eligibility

Male

Study type

Interventional

Phase

Not applicable

Primary location

Karabuk University Faculty of Sports Sciences

Karabük, 78000, Turkey (Türkiye)

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • keep healthy
  • must be able to attend training regularly

Exclusion criteria

  • smoking habit
  • had orthopedic conditions that hindered lower-body resistance exercise, had hypertension (140/90 mm Hg), or had a BMI exceeding 30 kg/m2

Treatment and study plan

Low-load resistance exercise with blood flow restriction

Other

BFR-RE group performed bilateral leg extension exercises to volitional exhaustion (90 seconds rest between sets, 30% 1RM) with BFR cuffs applied at 60% of limb occlusion pressure.

Other names: (BFR-RE)

High-load resistance exercise

Other

The HL-RE group performed the same exercise to volitional exhaustion (90 seconds rest between sets, 70% 1RM) without BFR cuffs.

Other names: (HL-RE)

Primary outcomes

  1. Thigh Circumference

    Time frame: 2 day

    Measurement of thigh circumference was performed at a point 33% distal to the inguinal crease, precisely matching the intended cuff application site as verified by a trained investigator. The inguinal crease-to-superior patellar pole distance was also recorded using a standard anthropometric tape measure

  2. Muscle Strength Test

    Time frame: 2 day

    Prior to commencing the strength assessment, using a Lafayette Manual Muscle Testing System (Lafayette Instrument Company, Lafayette®) a period of familiarization was allowed between the examiner and participant. Subsequently, a trained examiner guided the participant through a series of practice repetitions of leg flexion, and leg extension movements until correct execution was confirmed. The order of movements was randomized. The participant was then verbally instructed to perform three maximal contractions for each movement (3-second hold). A 1-minute rest interval was incorporated between successive contractions, and a 3-minute rest interval was implemented between different movement sets. Measurement of leg extension were obtained with participants in a seated position, while leg flexion measurement were taken with participants in a prone position.

  3. Muscle Thickness Assessment

    Time frame: 4 day

    Subjects had not engaged in physical activity before the study (48-72 hours), and muscle thickness (MT) was measured at a prone rest position. All muscle thickness measurements were obtained with a single ultrasound device equipped with a 2-9 MHz linear transducer. A researcher (medical doctor, N.K.K) who was blinded to the exercise groups with more than 10 years of experience in musculoskeletal imaging performed all measurement

  4. Muscle Stiffness and Shear Wave Elastography

    Time frame: 4 day

    After the muscle thickness measurements, the stiffness measurements of quadriceps muscle were obtained using the shear wave elastography (SWE) imaging option of the same ultrasound device with the same linear transducer.

Other outcomes

  1. Anthropometric Measurements

    Time frame: One day

    Height, weight and Body mass index (BMI) were measured using a stadiometer (InBody 270 (Biospace, California, USA), with subjects wearing light clothing and no shoes. Measurements were taken before the exercise program.

  2. Blood Pressure

    Time frame: One day

    After a 5-minute supine rest, participants' left brachial blood pressure (BP) was measured twice (1-minute interval). The average of the two closest readings (within 5 mmHg) was recorded in mmHg

  3. Heart Rate

    Time frame: One day

    After a 5-minute supine rest

Sponsors and collaborators

Lead sponsor

Karabuk University

Other

Registry information

Important dates

Study start
2024
Primary completion
2025
Study completion
2025
First posted
Dec 24, 2024
Registry last updated
Mar 4, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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