Pearson, Jeremy; Wadhi, Tanuj; Barakat, Christopher; Aube, Daniel; Schoenfeld, Brad J.; Andersen, Jody C.; Barroso, Renato; Ugrinowitsch, Carlos; De Souza, Eduardo O.

Journal of Strength and Conditioning Research: August 2022 - Volume 36 - Issue 8 - p 2162-2168, doi: 10.1519/JSC.0000000000003953

PURPOSE:

To compare the effects of FAST and SLOW eccentric repetition tempo in a single exercise volume-matched intervention on muscle thickness (MT) and strength in resistance-trained men.

PROCEDURES:

13 subjects had each leg randomly assigned to SLOW (1-0-3 = 1 second concentric, no pause, 3 seconds eccentric) or FAST (1-0-1) repetition tempo.

Subjects underwent an 8-week strength-training (ST) intervention performed twice weekly.

Test were single-leg leg extension one repetition-maximum (1-RM) and anterior thigh (MT) at the proximal (MTP) and distal (MTD) portions were assessed via ultrasound imaging at baseline and after 8 weeks of RT. Rating of perceived exertion (RPE) assessments of the training sessions (i.e., 16 per leg) were averaged for further analysis.

CONCLUSIONS:

Both legs similarly increased MTP @ FAST= 0.094 in./0.24 cm, 3.6% and SLOW = 0.079 in./0.20 cm, 3.1%).

However, for MTD, analysis of covariance analysis showed a leg effect in which absolute pre-to-post change was greater in FAST compared with SLOW @ FAST 0.090 in./0.23 cm, 5.5% and SLOW: 0.051 in./0.13 cm, 2.2%).

Regarding the 1-RM, both legs similarly increased maximum strength @ FAST = 20 lbs./9.1 kg, 17.0% and SLOW: 22.9 lbs./10.4 kg, 22.1%.

The SLOW group had a higher RPE than FAST @ 8.59 vs. 7.98.

So, both the 1-0-1 and 1-0-3 rep tempos produced similar muscular adaptations, the perceived effort was greater in the SLOW, but the FAST tempo may provide a small hypertrophic advantage at the distal quadriceps.

IN PLAIN ENGLISH:

Is the miniscule hypertrophic advantage in one section of a muscle worth the risk of incurring an injury by moving the resistance fast? Because moving slower – ALL OTHER FACTORS BEING EQUAL – is just as effective but safer than moving fast, slow it down and live to see another injury-free day.