We hear lots of narratives about stretching before lifting. Some lifters insist on stretching before training. Others claim that it hurts performance.
But what does the research say?
Behm et all did a systematic review of research on the effects stretching.1 They looked at the effect of stretching pre-exercise on strength. They examined other variables too, but we’ll focus on strength today.
What studies were included?
The review included 125 studies looking at:
- Static stretching – holding a muscle at its lengthened position.
- Dynamic stretching – moving joints through their full range of motion.
- Proprioceptive Neuromuscular Facilitation (PNF) stretching – a technique of contracting and relaxing muscles to increase flexibility.
How did stretching pre-exercise affect strength?
Generally, static stretching and PNF stretching caused a decrease in strength afterwards. Dynamic stretching did not affect strength much afterwards.
Static Stretching
Static stretching was associated with a 4.8% decrease in strength.
But the story doesn’t end there. The researchers found a “dose-response relationship”. Meaning that as stretch duration increased, strength was further decreased. For stretches performed for < 60 seconds, strength decreased by 2.8%. However, when stretches were held for > 60 seconds, strength decreased by 5.1%.
Dynamic Stretching
Dynamic stretching had trivial effects on strength. Strength decreased by only 0.23%.
PNF Stretching
PNF stretching was similar to static stretching – it was associated with a 5.5% decrease in strength.
It makes sense that PNF stretching would follow the same trend as static stretching. Both involve relaxing and holding muscles at their end range.
What does this mean for lifting?
-If you want to maximize strength, do static stretching after training.
-If you really want to do static stretching before training, keep it brief (30 seconds per stretch). Research suggests that a 30 second stretch increases flexibility as much as a 60 second stretch.2
-Dynamic stretching before training has trivial effects on strength.
I personally do not have clients stretch before lifting. In addition to this research, I’ve observed that static stretching is relaxing and calming. Before training, we want to get amped up and excited – the opposite of lying on the ground relaxing into stretches.
Static stretching can feel great. But to maximize lifting performance, save it for after training.
References
- Behm, D. G., Blazevich, A. J., Kay, A. D., & McHugh, M. (2016). Acute effects of muscle stretching on physical performance, range of motion, and injury incidence in healthy active individuals: a systematic review. Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme, 41(1), 1–11. https://doi.org/10.1139/apnm-2015-0235
- Bandy, W. D., Irion, J. M., & Briggler, M. (1997). The effect of time and frequency of static stretching on flexibility of the hamstring muscles. Physical therapy, 77(10), 1090–1096. https://doi.org/10.1093/ptj/77.10.1090
Dr. Jahan: Engineer, Doctor of Physical Therapy 