Does Stretching Enhance Recovery?
As previously mentioned, the primary objectives of post-exercise stretching to enhance recovery are two-fold:
- Reduce muscle soreness
- Reduce muscle stiffness (i.e. regain pre-exercise ranges of motion)
Before continuing, it is worth noting that other post-exercise modalities such as heat and cold therapies, vibration, massage, hydrotherapy, anaesthetics, and foam rolling have all been shown to reduce muscle soreness and enhance the joint range of motion; thus enhancing recovery [9-17].
During static stretching, blood flow, capillary region oxygenation, and the velocity of red blood cells to the muscle appear to decrease [18-21]. Perhaps this is to be expected as the mechanical strain exerted on the muscle from the stretch is likely to cause vascular compression and lengthening. However, immediately after the stretch is released, blood flow appears to significantly increase beyond its previous pre-stretching levels .
Static stretching, therefore, appears to induce a rebounding effect on muscle blood flow – i.e. reduces flow during the stretch, but quickly elevates it afterwards. Temporarily reducing, and then increasing, blood flow may facilitate recovery by improving the delivery of nutrients whilst simultaneously removing metabolites, however, this is yet to be confirmed by research.
Reducing muscle soreness after exercise is a cornerstone objective of enhancing recovery. Much research has measured the effects of post-exercise stretching on muscle soreness and very often found positive results ; simply meaning stretching after exercise reduces muscle soreness.
Having said this, most of this research has been reported to be of low to moderate quality . One extensive meta-analysis on this topic, including over 2,500 participants, concluded that post-exercise stretching for recovery only reduced the effects of muscle soreness by 1-4 points on a 100-point scale (1-4% improvement) . Despite this figure being statistically significant, the effect is very small. As such, post-exercise static stretching may have little, to no, worthwhile effect on muscle soreness. On the flipside, perhaps every little counts?
Things here can get a little complicated, so we will keep it as quick and as straightforward as possible.
The Autonomic Nervous System is comprised of two branches (Figure 3):
- Sympathetic Nervous System (SNS)
- Parasympathetic Nervous System (PSNS)
The easiest way to distinguish the differences between the two is to associate the “fight or flight” responses with the SNS, and “rest and digest” responses with the PSNS. Therefore, the SNS increases heart rate, whilst the PSNS slows it down (Figure 3). Essentially, the PSNS helps facilitate recovery after a stressful event (e.g. competition or training) by counteracting the effects of the SNS which raises excitability and readiness .