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BLOOD FLOW RESTRICTION (BFR) VS. ECCENTRIC TRAINING: SIDE BY SIDE ANALYSIS AND APPLICATION

By: Zachary Amster, SPT, CSCS

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Learning Objectives

Mechanism
When are BFR & Eccentric Training applicable?
Pros and Cons of BFR & Eccentric Training
Can BFR & Eccentric Training be used together?
Summary / Key takeaways

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Effects (Direct and Indirect)

↑ GH, ↑ IGF-1, ↑ mTORC1, ↑ myokines, ↑ VEGF, ↑ MPS, ↑ MSC’s
↓ Threshold of activation for fast twitch muscle fibers, ↓ stimulation of α-motor neurons,
↑ increased MU recruitment, ↑ muscle fiber recruitment, ↑ CSA of muscle fibers

Adaptations occur due to metabolite accumulation and hypoxic environment, resulting in greater muscle activation, fatigue, and anabolic signaling compared to load and intensity matched exercise without BFR. (Lorenz et al., 2021)

Definition: Blood flow restriction (BFR) is a training method partially restricting arterial inflow and fully restricting venous outflow in working musculature during exercise (Scott et al., 2015)

Blood Flow Restriction (BFR)

**Talk about the last two smaller bullets**

Most responses are due to the hypoxic and acidic environment

In summary, blood ow restriction training (BFRT) subjects muscles to hypoxic and acidic conditions, stimulating adaptive responses in muscle fibers, including enhanced activation and recruitment of fast-

twitch (FT) fibers. (Chu et al., 2025) **The environment created by BFR induces a unique physiological state that effectively activates fast-twitch (FT) muscle fibers, which are particularly important for explosive activities requiring high intensity and short duration. In this way, training conditions at lower intensities may in some ways achieve similar results to high intensity training. Blood flow restriction training enhances the recruitment of fast-contracting muscle fibers compared to load-and-volume matched exercise training, which may contribute to muscle strength gain. Furthermore, blood flow restriction training can improve muscle endurance performance because it forces muscles to work under conditions of limited oxygen supply.**

**BFR induces metabolic accumulation, which subsequently activates key signaling pathways and regulates specific protein synthesis effectors. Together, these components form a complex and intricate regulatory network that effectively promotes muscle protein synthesis and increases muscle volume**

Inflammatory response causes increase release of Myokines = interleukin 6

GH = Growth Hormone

IGF = Insulin Like Growth Factor

mTORC1 = mechanistic/ mammalian target of rapamycin complex 1

MPS = Muscle Protein Synthesis

VEGF = vascular endothelial growth factor

MSC = Muscle Satillete Cells

CSA = Cross sectional area

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Blood Flow Restriction (BFR)

BFR Resistance Training is often implicated in cases where higher loads required for improvements in strength and hypertrophy are contraindicated, such as (Hedt et al., 2022, Saraf et al., 2022):

In patients post-operatively,

In patients with weight bearing restrictions
In ACLRs, to help improve initial quadriceps activation

In patients who are reactive to higher loads,

In arthritic patients
In Athletes, to maximize strength gains without overloading joints

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Blood Flow Restriction (BFR)

Brief Protocol BFR Resistance Training (Lorenz et al., 2021, Patterson et al., 2019)

Cuff placed as proximal on limb as possible
LOP

Upper Extremity = 40 – 60%
Lower Extremity = 60 – 80 %

Load = 20 – 40% 1 RM
Sets = 2-5 per exercise
Repetitions = 45 – 75
Rest period = 30 – 60s
Total Occlusion Time ≤ 10 min

Common Set & Rep Scheme for BFR usage:

30, 15, 15, 15

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Blood Flow Restriction (BFR)

Pros	Cons
Muscle Adaptations with lower loads	Discomfort / Pinching
Can prevent disuse atrophy during immobilization	Risk of DVT
Limits load on joints	Bruising
Aerobic / Cardiovascular Benefits	Contraindicated for certain patients
Early Post Operative Strength Gains	Expensive Equipment
Potential Pain Reduction

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Eccentric Training

Effects (Direct and Indirect)

↑ Addition of sarcomeres in series and in parallel, ↑ Fascicle / Fiber Length, ↑ microlesions, ↑ IGF-1, ↑ Testosterone concentration, ↑ GH
↑ CSA Distally, ↑ Overall Anabolic Signaling

Definition: Eccentric muscle actions occur when the load applied to the muscle exceeds the force produced by the muscle itself, resulting in a lengthening action. (Douglas et al., 2017)

*****MAKE SURE TO NOTE THE ARROW POINTING TO THE MECHANICAL STRESS PART AND HOW THAT’S THE MOST IMPORTANT PART OF THE ECCENTRIC TRAINING, THAT AND THE LACK OF METABOLIC STRESS****

Multiple studies have said that the increased force production during eccentrics is due to the spring like action of titin in addition to the normal action of actin and myosin

During eccentric contractions, passive muscular tension develops because of lengthening of extramyofibrillar elements, which can contribute to an increased acidic environment. Which will facilitate an adaptive hypertrophic response, which is similar to most anabolic exercise. Mechanical tension produced by force generation and stretch contributes to muscle ischemia which can lead to metabolic adaptations within the skeletal muscle. . (Hedayatpour et al., 2015)

Picture (Hody et al., 2019)

Although this may seem unexpected, given the higher training load in the ECC condition, these findings are in line with several studies, even when CON and ECC training was matched for load or neural drive, One explanation is that ECC actions do not elicit a higher mechanical load, but they generate higher forces through the stretch and recoil of passive structures, such as titin, which might act as a molecular spring, increasing force output during lengthening ac- tions,3 consistent with our training data. Conversely, Franchi et al20 argued that perhaps ECC actions do indeed produce a greater mechanical stimulus, but the hypertrophic response to ECC training is blunted by inflammatory responses and muscle damage, which is higher in ECC compared with CON actions. (Benford et al., 2020)

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Eccentric Training

Eccentric Training is always a good form of resistance training due to its functional importance, but there are some scenarios where it is specifically implicated such as (Tyler et al., 2017, LaStayo et al., 2003, Couppe et al., 2015):

Muscular Strain injuries
Tendinopathies
Injury Prevention
Fall Risk Patients
Post Operatively

ACLRs, Arthroplasties

Metabolically limited populations

Eccentrics work well because they allow for greater muscle force production while at a lower energy cost

I added tendinopathies although as of recent it has been shown that type of contraction doesn’t matter, rather tendons just respond to load

Eccentric rehabilitation applications for individuals with a variety of age and/or medical-related conditions, all of which share muscle atrophy, weakness, and physical dysfunction as common impairment (LaStayo et al., 2014)

For all populations mentioned in the picture, the rational for most are because it requires low energy costs with higher force production allowing for greater strength improvements, power improvements, and more stability improvements. The actual article I got this from reviewed several studies and I can definitely give it to anyone interested (LaStayo et al., 2014)

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Eccentric Training

Brief Protocol Eccentric Training (Tyler et al., 2017, Alfredson et al., 1998, Solie et al., 2024, Burgos-Jara et al., 2023, )

Position = Lengthened Position of target muscle
Load = 70 – 140 % Concentric 1 RM*
Sets = 2-5 per exercise
Repetitions = start with 10, progress to 15
Rest period = 30 – 240s

Slow Progression of load and duration are crucial!

*Speed of repetition is debatable, while slower repetitions increase time under tension which has been linked to improvements in hypertrophy and strength, studies of quicker eccentric contractions have shown greater improvements in muscular strength, power, and RFD, therefore speed of contraction would be considered debatable imo

There are many variations of Eccentric training protocols, so this is just one version of many, which is combining similar aspects from different articles

Because eccentrics are tied to muscle soreness and muscle damage, it is important to slowly progress the load and duration, because for any muscle that is not experienced with eccentrics, muscle damage is inevitable, but the beenfits from high force eccentrics are possible without the same level of muscle damage and soreness (LaStayo et al., 2014)

*According to mal this is not accurate, but I have not seen much saying lower loads are as beneficial

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Eccentric Training

Pros	Cons
Rightward Shift in Length Tension Relationship	Increased DOMS
Increases Flexibility	Less muscle activation compared to concentric contractions
Improved efficiency of Stretch Shortening Cycle (SSC)	Higher Risk of Overtraining
Less Metabolically demanding	Requires heavier loads*
Injury Protective
Cross Education between extremities**

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Comparison

Criteria	BFR Training	Eccentric Training
Load Intensity	Low-load (20-40% 1RM)	High-loads >70% 1RM
Mechanism	Hypoxia and Metabolic Stress	Mechanical Load and Muscle Damage
Primary Use	Early Post Op, Low Load Tolerance	Tendinopathies, Post Op, Metabolically Limited Populations, Advanced Strength Training
Clinical Benefits	↑ Strength, ↑ Hypertrophy, ↑ Endurance,	↑ Power, ↑ Strength, ↑ RFD, ↑ Tendon Stiffness, ↑ Flexibility
Limits	Equipment Cost, Discomfort, Safety Concerns (some contraindications)	DOMS, usually higher load,

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Question for Everyone…

Can BFR and Eccentric Training be combined?

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Together or not? Well, lets look at some research

A 2025 Article compared High Load Eccentric Training with BFR, Low Load Eccentric Training with BFR, High Load Eccentric Training without BFR, & Low Load Eccentric Training without BFR

After 6 weeks of training, results were:

All Groups increased similarly in Eccentric, Isometric, and Concentric Torque except for the Low Load without BFR

Biral et al., Apunts, 2025

A 2015 Pilot Study compared hypertrophic and strength adaptations between eccentric and eccentric with blood flow restriction groups

After a 4-week training program, results were:

Boths groups had significant improvements in Muscle CSA
No increase in concentric muscular strength

Pope et al., IJSSC, 2015

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Together or not? Well, lets look at some research

A 2012 Study, investigated effects of low-intensity blood flow restricted concentric or eccentric resistance training on muscle size and strength

After 6 weeks, results were:

Con-BFR had greater increases in CSA compared to Ecc-BFR throughout the muscle

Ecc-BFR only showed increases in CSA towards the distally

Only Con-BFR had significant improvements in MVC, although both increased

Yasuda et al., PLOS one, 2012

An Article from 2022 compared the effects of BFR Training on eccentric hamstring strength, power, lean mass, and perceived soreness. Comparing the effects of a low load BFR eccentric lower extremity intervention to a high load eccentric low extremity intervention

After 6 weeks, results were:

Both groups had similar effects on power, strength, lean mass, and perceived soreness

Jones et al., JSCR, 2022

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