The current study adds to the existing literature that lifting tempo is not a big factor for muscle growth when training programs are similar.
SLOW REPS VS FAST REPS: DOES GREATER TIME UNDER TENSION BUILD MUSCLE SUMMARY
- TUT (Time Under Tension) Training does not result in greater gains in muscle growth if the sets are taken to failure.
- Lifting tempo has very little impact on muscle growth. There is a large range of repetitions speeds (0.5 to 8 seconds) that can increase muscle growth.
- When TUT is equalized between groups, slow and fasting lifting have similar effects on muscle growth.
9/18 RESEARCH UPDATE: NO EVIDENCE THAT SLOWER REPETITIONS CAUSE MORE MUSCLE GROWTH WHEN TIME UNDER TENSION IS SIMILAR
This month another study casts doubt on the myth that slower repetitions are better for muscle growth. Researchers had subjects perform bench presses three times per week at 50-55% of 1RM for 10 weeks. One group was assigned to use slower repetitions at a cadence of three seconds up and three seconds down for six repetitions (i.e., the slower lifting group), while the other group lifted the weight with a cadence of 1.5 seconds up and 1.5 seconds down for 12 repetitions (i.e., faster lifting group).
Despite the different lifting speeds, both groups performed the same amount of time under tension (TUT). TUT is defined as the duration of time in which a muscle is exposed to tension. TUT was equated between groups (36 seconds). For example, the faster lifting group performed 3 seconds of TUT (1.5 seconds up and down) for 3 sets x 12 reps = 36 seconds of TUT. The slower cadence group performed 6 seconds of TUT (3 seconds up and 3 seconds down) for 3 sets x 6 repetitions = 36 seconds of TUT. At the end of the study, the group performing 12 repetitions performed a higher total training volume. Still, when the TUT was controlled to be similar between the lifting groups, both had equal gains in strength and muscle mass.(9)
GREATER TIME UNDER TENSION FOR MUSCLE GROWTH? FACT VS FICTION
Although training volume is important for muscle growth, it’s not the single determining factor for muscle growth. This study found that the higher repetition group performed more repetitions and thus greater total training volume, yet muscle growth was similar. In conclusion, training protocols with the same TUT promote similar strength gains and muscle hypertrophy.
Moreover, considering that the protocols used different numbers of repetitions, the results indicate that training volumes cannot be considered separately from TUT when evaluating neuromuscular adaptations.
Older data has suggested that slower lifting is better for muscle growth, but the data was flawed because the studies did not equate TUT between lifting groups. For example, if two groups train with a similar number of reps, but one group has to lift the weight slower, the total TUT will be higher for the slower group. When researchers have designed studies to make TUT similar between groups, the differences in muscle growth are similar.
There does not seem to be any benefit to deliberately slowing down repetition speed, as muscle growth can occur in a large range of contraction durations (0.5- 8 seconds). It may be beneficial to add a few sets with a slower repetition cadence for the eccentric portion, but consistently training with a slower eccentric portion does not seem to result in greater muscle growth.
IS TIME UNDER TENSION A MYTH?
At first, the recommendation was to lift the weight as slowly as possible on the way down or during the eccentric portion of the lift for maximal muscle growth.(1) Others have found that faster eccentrics resulted in more muscle growth.(2, 3) Talk about confusing! Brad Schoenfeld did a meta-analysis in 2015 and found that muscle growth can occur at a wide range of repetition tempos ranging from 0.5 to 8 seconds.(4) Other researchers have found when sets are taken to failure, repetition speed does not matter as muscle growth is similar, independent of the lifting tempo. (5, 6)
A 2021 review of the literature reported that slow or fast movement tempos are more or less effective for muscle growth. (7) Researchers set out to confirm if repetition tempo made a difference in muscle growth. Subjects were assigned to three different resistance exercise groups training tempos over ten weeks.
- Group A: 3 Seconds Protocol: lifting in 1.5 seconds for concentric contraction and lowering in 1.5 seconds for the eccentric muscle actions.
- Group B: 6 Seconds Protocol: lifting in 3 seconds for concentric contractions and lowering in 3 seconds for the eccentric muscle actions.
- Group C: Control Group
The groups were evenly matched for Time Under Tension (i.e., 36 seconds per set), sets (3-4 sets), intensity (50-55% of a 1-RM), and rest periods (3 minutes). The subjects received an MRI before and after testing to measure muscle growth of the chest and triceps.
At the end of the study, there was no difference in muscle growth between the groups that lifted the weight faster with a 1.5-second tempo versus slower with a 3-second temp.(8) Both groups increased strength similarly with increases in 1RM. The current study adds to the existing literature that lifting tempo is not a big factor for muscle growth when training programs are similar.
1. Iodice P, Trecroci A, Dian D, Proietti G, Alberti G, Formenti D. Slow-Speed Resistance Training Increases Skeletal Muscle Contractile Properties and Power Production Capacity in Elite Futsal Players. Frontiers in Sports and Active Living. 2020;2.
3. Shepstone TN, Tang JE, Dallaire S, Schuenke MD, Staron RS, Phillips SM. Short-term high- vs. low-velocity isokinetic lengthening training results in greater hypertrophy of the elbow flexors in young men. J Appl Physiol (1985). 2005;98(5):1768-76.
6. Chaves TS, Pires de Campos Biazon TM, Marcelino Eder Dos Santos L, Libardi CA. Effects of resistance training with controlled versus self-selected repetition duration on muscle mass and strength in untrained men. PeerJ. 2020;8:e8697.
8. Martins-Costa HC, Lacerda LT, Diniz RCR, Lima FV, Andrade AGP, Peixoto GH, et al. Equalization of Training Protocols by Time Under Tension Determines the Magnitude of Changes in Strength and Muscular Hypertrophy. The Journal of Strength & Conditioning Research. 2022;36(7):1770-80.
9. Martins-Costa HC, Lacerda LT, Diniz RCR, Lima FV, Andrade AGP, Peixoto GH, et al. Equalization of Training Protocols by Time Under Tension Determines the Magnitude of Changes in Strength and Muscular Hypertrophy. J Strength Cond Res. 2022;36(7):1770-80.