Low-Intensity BFR Cycling: Impact on VO₂Max and Muscle Adaptations

Kahramanmaraş Sütçü İmam University (KSU)

Status: Completed

Conditions: Aerobic Capacity; VO2max; Isokinetic; Muscle Strengh; Blood Flow Restriction Exercise; Blood Flow Restriction (BFR) Training Effects

Treatments: Procedure: Cycling with Blood Flow Restriction (15 min at 40% VO₂max with 60-80% LOP); Procedure: Cycling Exercise (40 min at 40% VO₂max); Procedure: Short-Duration Cycling Control (15 min at 40% VO₂max)

Study type: Interventional

Funder types: Other

Identifiers

NCT07114835

BFR-Cycling-2025

Details and patient eligibility

About

This study aims to investigate the effects of low-intensity cycling exercise combined with blood flow restriction (BFR) on maximal oxygen consumption (VO₂max), muscle strength, and muscle thickness in sedentary adult males. Participants will be randomly assigned to three groups: (1) a cycling exercise group performing 40 minutes of cycling at 40% VO₂max, (2) a cycling with blood flow restriction group performing 15 minutes of cycling at 40% VO₂max with limb occlusion pressure at 60-80%, and (3) a control group following a shorter cycling protocol. Muscle thickness, isokinetic knee strength, and VO₂max will be measured before and after the 9-week intervention. The study is designed to evaluate whether short-duration, low-intensity cycling with BFR can induce physiological adaptations comparable to traditional longer-duration cycling protocols.

Full description

This study is designed to examine the effects of low-intensity cycling exercise combined with blood flow restriction (BFR) on aerobic capacity (VO₂max), isokinetic knee strength, and muscle thickness in sedentary male adults. Traditional methods for improving aerobic capacity and muscle strength often involve high-intensity or long-duration training protocols. However, such protocols may not be feasible for all individuals, particularly during rehabilitation, periods of detraining, or in populations with limited exercise tolerance.

Blood flow restriction training has gained attention as a promising strategy to elicit muscular and cardiovascular adaptations using lower intensities. The technique involves applying individualized limb occlusion pressure (LOP) via pneumatic cuffs during exercise to partially restrict arterial inflow and fully restrict venous outflow. This restriction is thought to create a hypoxic environment and increase metabolic stress, which may enhance the recruitment of fast-twitch muscle fibers and stimulate physiological adaptations.

In this randomized controlled trial, participants are allocated to one of three groups: a standard cycling exercise group (40 minutes at 40% VO₂max), a BFR cycling group (15 minutes at 40% VO₂max with 60-80% LOP), and a control group (15 minutes at 40% VO₂max without BFR). All exercise sessions are performed three times per week for nine weeks. The LOP is adjusted across the training period to progressively increase the stimulus in the BFR group.

Baseline and post-intervention assessments include measurements of body height and weight, ultrasound-based muscle thickness, isokinetic knee strength testing, and graded exercise testing for VO₂max. The goal is to determine whether low-intensity, short-duration cycling with BFR can serve as a practical and effective alternative to longer-duration exercise programs.

Enrollment: 24 patients

Sex: Male

Ages: 18 to 24 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Individuals aged between 18-24 years,
• Individuals without any health problems,
• Individuals who do not actively participate in sports,
• Individuals who marked all items as no on the H+cuff participant information form,
• Individuals who have not had a sports injury that would prevent them from participating in sports in the last 6 months,

Exclusion criteria

• history of lower extremity injury, respiratory disorders and refusal to participate

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Single Blind

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24 participants in 3 patient groups

Cycling Exercise - 40 min at 40% VO₂max

Experimental group

Description:

Participants in this group perform low-intensity cycling exercise at 40% of their VO₂max for 40 minutes per session, three times per week, over a 9-week period. All sessions are conducted on an electronically braked Astrand cycle ergometer. This group does not receive blood flow restriction.

Treatment:

Procedure: Cycling Exercise (40 min at 40% VO₂max)

Control - 15 min Cycling at 40% VO₂max

Active Comparator group

Description:

Participants in the control group perform cycling exercise at 40% of their VO₂max for 15 minutes per session, three times per week for 9 weeks. The exercise is performed on an electronically braked Astrand cycle ergometer. No blood flow restriction or additional intervention is applied in this group.

Treatment:

Procedure: Short-Duration Cycling Control (15 min at 40% VO₂max)

Cycling + BFR - 15 min at 40% VO₂max with 60-80% LOP

Experimental group

Description:

Participants in this group perform cycling exercise at 40% of their VO₂max for 15 minutes per session, three times per week for 9 weeks. During each session, pneumatic cuffs are applied to the proximal thighs to restrict blood flow, with individualized limb occlusion pressure (LOP) set at 60% in weeks 1-4, 70% in weeks 5-7, and 80% in weeks 8-9. The exercise is performed on an electronically braked Astrand cycle ergometer.

Treatment:

Procedure: Cycling with Blood Flow Restriction (15 min at 40% VO₂max with 60-80% LOP)