Perceptual, Hemodynamic and Cardiovascular Responses of Two Different BFR Training Protocols
Condition: Healthy
Study type: Interventional

Summary: 
      BFR training is growing in popularity and a variety of devices are on the market for clinical
      use. One way in which it is thought that BFR resistance training safety can be increased is
      by using a BFR cuff that regulates the applied pressure to the limb during each repetition.
      This is thought to reduce perceptual, hemodynamic and cardiovascular responses to
      non-autoregulated approaches, theoretically increasing long-term compliance and safety with
      BFR training.
    

Detailed description: 
      BFR training is growing in popularity and a variety of devices are on the market for clinical
      use. One way in which it is thought that BFR resistance training safety can be increased is
      by using a BFR cuff that regulates the applied pressure to the limb during each repetition.
      This is thought to reduce perceptual, hemodynamic and cardiovascular responses to
      non-autoregulated approaches, theoretically increasing long-term compliance and safety with
      BFR training.

      However, only one study has directly compared the effect of an autoregulated vs.
      non-autoregulated and their design did not standardize the cuff width between the
      autoregulated and the non-autoregulated cuff, potentially leading to differences in observed
      outcomes. That study concluded that autoregulated cuffs better manage the hemodynamic and
      perceptual responses to non-failure training protocols while providing a more accurate
      cuff-limb interface pressure, thus increasing safety profile. Moreover, BFR resistance
      training is commonly performed to failure so it is unknown whether the use of regulated
      pressures influences fatiguability or alters perceptual, cardiovascular and hemodynamic
      responses compared to a non-autoregulated cuff.

      Therefore, the purpose of this study is to compare the perceptual, hemodynamic and
      cardiovascular responses using either an autoregulated pressure or a non-autoregulated
      pressure during a 20% 1RM leg extension non-failure and failure protocol in healthy,
      recreationally active male and female participants (without any history of BFR training)
      using the SmartTools Pro model (a device able to be autoregulated and non-autoregulated based
      on setting, providing an ability to directly compare autoregulation to non-autoregulation
      with a cuff of similar width).

      Each participant will perform one familiarization session to determine 1RM, take baseline
      data for participant characteristics including limb occlusion pressure and relevant
      hemodynamic and cardiovascular measures, acclimate to the non-failure protocol without blood
      flow restriction and anchor perceptual baselines. Following familiarization session and at
      least 6 days between sessions, the dominant leg of each participant will be randomized to
      either the autoregulated or non-autoregulated pressure setting. Each participant will perform
      4 sets of exercise applied in a continuous application setting using a commonly recommended
      protocol of 30-15-15-15 using a 2 second concentric/2 second eccentric tempo with 30-45
      seconds of interset rest. The BFR cuff will either be set to autoregulation or
      non-autoregulated pressure setting. Following completion of the protocol, with the cuffs
      still inflated, all variables will be assessed again before deflating. Participants will
      return to the lab at least 6 days later at a similar time and perform the same protocol with
      the opposite condition.

      To assess the differences in all relevant outcome measures during a failure routine, the same
      protocol will be completed 6 days later with each participant randomized to either the
      autoregulated or non-autoregulated group. Participants will complete a similar resistance
      training program using 4 sets to volitional fatigue instead of the non-failure protocol. The
      data provided within this study could greatly inform clinical practice if responses to
      non-autoregulated cuff applications in both non-failure and failure routines are heightened
      compared to autoregulated cuff applications. This study will also provide preliminary data
      for application in clinical populations such as those with knee osteoarthritis as well as
      applying a similar strategy to healthy populations in the upper extremity to determine if
      similar responses exist between limbs.
    

Intervention name(s): Autoregulated Blood Flow Restriction Cuff (smart-cuff pro devices, acting as pressurized tourniquet) combined with low load strength training; Non-autoregulated blood flow restriction cuff ((smart-cuff pro devices, acting as pressurized tourniquet) combined with low load strength training)
Intervention type(s): Device; Device
Intervention description(s): This group will undergo 2 sessions consisting of a low load leg extension exercise combined with a pressurized tourniquet which autoregulates so when the quadriceps muscle contracts, the total amount of pressure doesn't increase, as the tourniquet will lower the pressure to keep the total amount of pressure constant.; This group will undergo 2 sessions consisting of a low load leg extension exercise combined with a pressurized tourniquet which does not autoregulate so when the quadriceps muscle contracts, the total amount of pressure will increase, as the tourniquet will not lower the pressure to keep the total amount of pressure constant.
Other intervention name(s): Kaatsu; Partial vascular occlusion; Kaatsu; Partial vascular occlusion
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Supportive Care
Keywords: Blood Flow Restriction; Strength training; Cardiovascular safety; Hemodynamics