Brief Inter-Set Stretching Doesn't Hurt Strength Performance, Study Finds
Twenty seconds of static stretching between sets maintains training volume and intensity while potentially saving time.
Does stretching between sets hurt your power output, or is it a waste of time? This study explored whether 20 seconds of static stretching between sets affects your ability to complete reps and maintain training volume on leg extensions.
Overview
This randomised controlled trial examined whether performing brief static stretches of the anterior chain (hip flexors, quads, and ankle extensors) between sets would impact strength performance metrics during knee extension exercises. The hypothesis was that short-duration stretching would not negatively affect performance variables.
Aim
The primary objective was to compare the effects of 20 seconds of anterior chain stretching performed between sets on total repetition volume (TV), volume load (VL), and training impulse (TRIMP) during knee extension exercises.
Methods
Eleven recreationally trained men (average age 27.3 years, 37.9 months of training experience) completed three laboratory visits. During the first visit, researchers tested each participant’s one-repetition maximum (1RM) on a single randomly selected leg, with an average 1RM of 57.7 kg. In visits two and three, participants completed four sets of knee extensions at 70% of 1RM (approximately 40.8 kg). One session involved passive rest between sets (control condition), while the other incorporated 20 seconds of static stretching of the entire anterior chain at maximum pain tolerance, followed by 1 minute and 40 seconds of rest (experimental condition). The order of conditions was randomised, and the OMNI-RES perceived exertion scale was applied after each set. Volume load was calculated as total repetitions multiplied by external load, while TRIMP was calculated as VL multiplied by RPE
Results
The data revealed no significant differences between the stretching and non-stretching conditions across all measured variables. For individual sets, testing showed no significant differences for sets 1, 2, 3, and 4, respectively. Total repetition volume remained essentially identical between conditions: 34.3 ± 4.9 repetitions without stretching versus 33.9 ± 6.3 repetitions with stretching (p = 0.881). Volume load also showed no meaningful difference: 1405.3 ± 515.8 kg without stretching compared to 1367.0 ± 454.0 kg with stretching (p = 0.855). Training impulse demonstrated no significant differences between groups (10,120.8 ± 4,319.4 arbitrary units for control versus 9,582.6 ± 4,478.5 for stretching; p = 0.182). Perceived exertion ratings were similar across all four sets between conditions.
Practical Takeaways
For lifters looking to maximise training efficiency, this study provides reassuring evidence that brief inter-set stretching won’t sabotage your workout performance. You can safely incorporate 20-second static stretches of the anterior chain between leg extension sets without worrying about completing fewer reps or lifting less total volume.
This approach offers a time-efficient strategy to work on flexibility simultaneously with strength training, potentially eliminating the need for separate stretching sessions. The key is keeping stretching duration relatively short—20 to 30 seconds appears to be the safe zone based on this and similar research. However, be cautious with longer stretching durations (45 seconds or more), as other research has shown this can reduce performance. The stretching should be performed at maximum tolerable intensity but should target the entire kinetic chain involved in the movement (in this case, hip flexors, quads, and ankle extensors together).
Key Takeaways
Twenty seconds of static stretching between sets does not compromise strength endurance performance, total repetition volume, volume load, or overall training stress during knee extension exercises. This finding challenges concerns that any inter-set stretching inherently impairs acute performance. This means that for people who want to address both strength and flexibility within a single training session, without extending workout duration, inter-set stretching could be a viable option.
The critical factor appears to be stretching duration—brief protocols (20-30 seconds) preserve performance, while longer durations (45+ seconds) may reduce total work capacity based on comparative literature. The researchers strategically stretched the entire anterior chain simultaneously rather than isolating individual muscles, which may have practical advantages for multi-joint movements.
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Reference
Siqueira, J.P., Lopes, D.P., Inacio, P.A., Silva, R.A.S., Fonseca, D.F., Bittar, R.D., Rezende, A.C.A., Caixeta, D.A., Moreira, L.D.F., Lopes-Martins, R.A.B., Sales, M.M., & Sá Filho, A.S. (2024). Inter-set stretch: a preliminary randomised controlled comparison of knee extension strength performance in recreationally trained individuals. MTP&RehabJournal, 22, 1373.
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