(17) THE EFFECT OF TEMPO AND EXERCISE SELECTION WITH BLOOD FLOW RESTRICTION TRAINING ON MAXIMAL STRENGTH

Background: Low-load resistance training at 20-50% of the one repetition maximum (1RM) combined with blood flow restriction (BFR) has been shown to be an effective method to improve muscular strength.  Within program design, many variables can be manipulated including tempo and the use of open (OKC) and closed kinetic chain exercises (OKC).  In traditional resistance training, tempo is commonly varied, however, in BFR training the standard 1:0:1 is common.  Furthermore, both open and closed kinetic chain exercises have been used in BFR training but have not been directly compared.

Purpose: To evaluate the effect of manipulating exercise tempo and kinetic chain with BFR training of the lower body.

Methods: 40 resistance trained college-aged males participated in the study.  The subjects were randomized into one of four groups: knee extension normal tempo (KE_NOR), knee extension time under tension (KE_TUT), back squat normal tempo (BS_NOR), and back squat time under tension (BS_TUT).  The normal tempo group completed reps at 1:0:1 tempo, meaning 1 second eccentric, 0 second during the transition, and 1 second concentric.  The TUT group completed reps at 1:3:1 tempo.  Volume was manipulated to equate total time under tension between groups.  Cuff occlusion pressure was set at 130% of systolic blood pressure taken in the supine position.  All groups completed 18 progressive resistance training sessions over 6 weeks.  1RM measurements were taken pre and post training. Participants started at 20% of 1RM and progressed to 30% of 1RM after 9 sessions.  The primary outcome measures were absolute and relative changes in maximal strength.  A one-way ANOVA was used to compare differences between each of the intervention groups with a Bonferroni post hoc analysis.  Statistical significance was set at p ≤ 0.05.

Results:   All groups experienced a significant increase in maximal strength pre to post (p=0.006).  KE_NOR experienced larger changes in strength when compared to BS_NOR (+16.8kg; p=0.003) and BS_TUT (+15.2kg; p=0.008). KE_TUT experienced larger changes in strength when compared to BS_NOR (+15.5kg; p=0.007) and BS_TUT (+13.9kg; p=0.019). KE_NOR experienced greater relative changes in strength when compared to BS_NOR (+14%; p=0.004) and BS_TUT (+13.3%; p=0.006).

Conclusion:  There was no difference between normal tempo and time under tension groups. Gains in absolute strength were larger in the KE groups compared to the BS groups.  Relative strength gains were only larger in KE_NOR compared to BS groups.
PRACTICAL APPLICATIONS: Both OKC and CKC exercises are effective in improving lower body strength, confirming previous research.  Manipulating tempo had a neutral effect on strength gains, possibly allowing coaches and clinicians to deviate away from the standard 1:0:1 tempo when prescribing BFR training.

 

Acknowledgements: None