Eccentric Resistance Training With Blood Flow Restriction on Muscle Function

Subjects will be randomly assigned to two groups: an eccentric only resistance training group or an eccentric training plus blood flow restriction group. Subjects will train at a moderately low intensity on a multiple-joint eccentric device. Those in the blood flow restriction will wear blood flow restriction cuffs on their upper thighs to reduce blood flow during the brief protocol. The training session will occur twice per week and will last \~5 minutes, including a one minute warm up, a one minute cool down and a three minute workout phase. The training program will last 7 weeks. Testing will be conducted at baseline (following a one session familiarization), 4 weeks and after the end of the 7 week training period. Assessments will focus on muscle strength, function, and morphology (size).

• Exercise (Other): The interventions are a form or exercise, specifically resistance exercise.
• Eccentric plus blood-flow restriction (Other): Eccentric plus blood-flow restriction

Primary outcomes

• Eccentron maximal muscle strength [7 weeks]: Eccentric muscle strength will be assessed via Eccentron (BTE Technologies, Inc., USA), an seated isokinetic dynamometer.
• Local muscle hypertrophy [7 weeks]: Muscle size changes of the quadriceps muscle measured an ultrasound device (GE NextGen LOGIQ, Tampa, Florida, USA).
• Muscle mass [7 weeks]: dual energy x-ray absorptiometry device (DEXA) the Hologic Horizon W Dual X-ray absorptiometry (Hologic Canada ULC, Mississauga, ON, Canada) will be used to assess appendicular (lower body) mean mass.
• Muscle function [7 weeks]: Vertical jump height will assess 3 maximal countermovement attempts on a jump mat (Just Jump Technologies, Huntsville, AL, USA) that measures jump height based on flight time.

Secondary outcomes

• Muscle soreness [7 weeks]: local muscle soreness will be assessed throughout the duration of the intervention period using a Wagner force algometer.

Sex: All, ages: 18 Years to 30 Years, accepts healthy volunteers

Inclusion Criteria:

* 18-30 years of age
* currently engaged in some form of resistance training between 1-3 times per week
* must have been training aerobically, but no more than 3 hours a week for the past six months

Exclusion Criteria:

* Must not have had any surgery of the lower limbs within the past 1 year period
* Must not have any neuromuscular disorder (e.g., Muscular dystrophy etc.)
* < 76 inches tall (in order to fit on the training machine)
* Maximal strength of < 725 lbs for the eccentric training device
* If any of the subjects are pregnant or plan to be pregnant in the duration of the protocol.

For those randomized to the BFR group, if any of the subject's thighs are too large for the BFR cuffs (greater than 68 cm).

• Brennan J Thompson, PhD, Principal investigator, Utah State Univeristy