Time under tension decreased with blood flow-restricted exercise.
OBJECTIVE
Exercise to failure results in similar muscle protein synthesis responses, independent of intensity. However, low-intensity exercise likely requires more time under tension and those with injuries may be incapable of sustaining the mechanical stress to reach failure.


METHODS
The purpose was to determine whether elastic knee wraps (KW) provide a stimulus to decrease time under tension and overall volume of work while maintaining a similar level of metabolic stress.


METHODS
Thirteen healthy subjects participated in a randomized crossover study consisting of three trials. The first determined 1 repetition maximum (1RM) on the bilateral leg extension. Subjects were then assigned to a blood flow restriction (BFR) or control (CON) group. After trial 2, subjects crossed over to the opposite trial. KW were placed around the thigh of each leg during BFR. Leg extensions were completed at 30% 1RM until failure. Whole blood lactate (WBL) was taken pre-, post-, and 3 and 5 min postexercise. Heart rate (HR) was measured before, following the first and second sets, and 3 and 5 min postexercise.


RESULTS
This study found KW provide a BFR stimulus allowing failure to occur sooner with similar metabolic stress postreperfusion. There were no differences in HR at any time point.


CONCLUSIONS
These results may benefit populations that cannot sustain the mechanical stress of high-intensity exercise or low-intensity exercise that requires a longer sustained time under tension.
Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019-0615, USA. jploenneke@ou.edu
Jeremy P
JP
Loenneke
Jacob M
JM
Wilson
Abhishek
A
Balapur
Austin D
AD
Thrower
Jeremy T
JT
Barnes
Thomas J
TJ
Pujol
D000328:Adult; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D018592:Cross-Over Studies; D004734:Energy Metabolism; D005260:Female; D006339:Heart Rate; D006801:Humans; D007511:Ischemia / Q000378:metabolism / Q000503:physiopathology*; D007717:Knee; D008297:Male; D009119:Muscle Contraction; D018763:Muscle Fatigue; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000378:metabolism / Q000503:physiopathology*; D009825:Oklahoma; D012039:Regional Blood Flow; D055070:Resistance Training / Q000379:methods*; D013314:Stress, Mechanical; D013997:Time Factors; D055815:Young Adult