Post Exercise Stretching For Recovery
Tom, Andy & I are all from an Army background and one of the things that are apparent is that every physical training session is to end with a stretching cooldown. It's what you're taught at the Physical Training School so you'd assume it's worth doing. Well, we wanted to take a closer look as we weren't so sure. You can listen to the full discussion below or continue on for my written summary.
Let's Start With Some New Data
A lot of previous data that has looked at stretching after exercise for recovery has only ever looked at frequency and volume. So how often and for how long. What about the intensity of the stretches though? That should be recorded right?
This piece of data we found from 2018 did just that. They had 3 groups. 1 group did low-intensity stretching, 1 did high and 1 did no stretching. The results indicated that
Therefore, low-intensity stretching is likely to result in small-to-moderate beneficial effects on perceived muscle soreness and recovery of muscle function post-unaccustomed eccentric exercise, but not markers of muscle damage and inflammation, compared with high-intensity or no stretching.
Apostolopoulos NC, Lahart IM, Plyley MJ, Taunton J, Nevill AM, Koutedakis Y, Wyon M, Metsios GS. The effects of different passive static stretching intensities on recovery from unaccustomed eccentric exercise - a randomized controlled trial. Appl Physiol Nutr Metab. 2018 Aug;43(8):806-815. doi: 10.1139/apnm-2017-0841. Epub 2018 Mar 12. PMID: 29529387.
Looking at this data critically it's important to note that asking people to do certain intensities is going to be subjective as is perceived muscle soreness so we have to take this data for what it is. In does however show that you should be doing low intensity stretching if recovery is your aim. High intensity is more than likely going to cause more damage especially if you have not progressively adapted to said intensities. It's not 100% clear why low intensity is promoting recovery but we think it is perhaps due to promoting blood flow without causing any extra muscular stress. In regards to blood flow, we will discuss more on this later. Of course over the coming weeks/months we will be exploring other recovery methods and from what we know even with this singular study is that the amount of recovery promoted from post-exercise stretching is pretty insignificant when compared to other methods.
What You Really Want To Know. Do I Need To?
Most people go in with the impression that if they stretch after a workout they will reduce DOM's/muscle soreness the next day and help with injury prevention. While there is no harm in stretching after a workout it could be a waste of your time. In relation to DOM's and injury prevention, the data does not support stretching as a way of helping. Even with the singular paper shown earlier, these effects are minimal and the difference between doing it and not is not going to be night and day.
An example of such data and one we examined in the podcast is this systematic review
Background: Many people stretch before or after (or both) engaging in athletic activity. Usually the purpose is to reduce risk of injury, reduce soreness after exercise, or enhance athletic performance.
Objectives: The aim of this review was to determine effects of stretching before or after exercise on the development of post-exercise muscle soreness.
Search strategy: We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (to April 2006), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2006, Issue 2), MEDLINE (1966 to May 2006), EMBASE (1988 to May 2006), CINAHL (1982 to May 2006), SPORTDiscus (1949 to May 2006), PEDro (to May 2006) and reference lists of articles.
Selection criteria: Eligible studies were randomised or quasi-randomised studies of any pre-or post-exercise stretching technique designed to prevent or treat delayed-onset muscle soreness (DOMS), provided the stretching was conducted soon before or soon after exercise. To be eligible studies must have assessed muscle soreness or tenderness.
Data collection and analysis: Methodological quality of the studies was assessed using the Cochrane Bone, Joint and Muscle Trauma Group's methodological quality assessment tool. Estimates of effects of stretching were converted to a common 100-point scale. Outcomes were pooled in a fixed-effect meta-analysis.
Main results: Of the 10 included studies, nine were carried out in laboratory settings using standardised exercise protocols and one involved post-exercise stretching in footballers. All participants were young healthy adults. Three studies examined the effects of stretching before exercise and seven studies investigated the effects of stretching after exercise. Two studies, both of stretching after exercise, involved repeated stretching sessions at intervals of greater than two hours. The duration of stretching applied in a single session ranged from 40 to 600 seconds. All studies were small (between 10 and 30 participants received the stretch condition) and of questionable quality. The effects of stretching reported in individual studies were very small and there was a high degree of consistency of results across studies. The pooled estimate showed that pre-exercise stretching reduced soreness one day after exercise by, on average, 0.5 points on a 100-point scale (95% CI -11.3 to 10.3; 3 studies). Post-exercise stretching reduced soreness one day after exercise by, on average, 1.0 points on a 100-point scale (95% CI -6.9 to 4.8; 4 studies). Similar effects were evident between half a day and three days after exercise.
Authors' conclusions: The evidence derived from mainly laboratory-based studies of stretching indicate that muscle stretching does not reduce delayed-onset muscle soreness in young healthy adults.
Herbert RD, de Noronha M. Stretching to prevent or reduce muscle soreness after exercise. Cochrane Database Syst Rev. 2007 Oct 17;(4):CD004577. doi: 10.1002/14651858.CD004577.pub2. Update in: Cochrane Database Syst Rev. 2011;(7):CD004577. PMID: 17943822.
Please see the show notes to our podcast episode for more linked data. We still aren't 100% on the exact cause of the feeling of DOM's but one theory is micro-tears. A potential cause that makes sense is that whenever we change things up. Example being changing volume, intensity and or frequency normally leads to increased soreness in the next few days. Once you adapt these effects seem to subside. What is clear though is that stretching straight after exercise will not do anything significant to reduce the effects.
The same goes for injury prevention. Once again see show notes for some examples of data on this. Here is a quote from one paper which looked at certain sports and effects of stretching on recovery. What's good about this is that sportsmen and women are working at a high level and always looking for small advantages to be had.
This conjecture is supported by the literature, where strong evidence exists that stretching has no beneficial effect on injury prevention in these sports. If this point of view is used when examining research findings concerning stretching and injuries, the reasons for the contrasting findings in the literature are in many instances resolved.
Witvrouw E, Mahieu N, Danneels L, McNair P. Stretching and injury prevention: an obscure relationship. Sports Med. 2004;34(7):443-9. doi: 10.2165/00007256-200434070-00003. PMID: 15233597.
Our honest advice would be to do what works for you. It comes down to time mainly. If you are normally short on time for physical exercise then spending 20 minutes post-workout stretching isn't really worth it however if you have ample time and feel really good doing a post-workout stretch then you aren't doing any harm (recommend low intensity) so go for it! The language used is important and when you see trainers/coaches telling people they must stretch after exercise you could be potentially creating a barrier to people hitting goals and getting results.
What Would We Personally Recommend?
As I said earlier in regards to that first study It could be about blood flow but my counterpoint would be that straight after exercise you already have blood flow to the exercised areas so doing light stretching to promote blood flow when it's already there seems a bit wasteful of time. So, instead, you may get more benefit from doing light stretching at other times of the day. Example doing a light stretching session before bed or when you first get up. I quite like the before bed option as it allows you to wind down, relax and reap the benefits of some daily stretching for things like flexibility and mobility which can aid in your exercise performance. It also may have slight benefits in recovery. This is where those calming stretching routines on YouTube are great.
Final Point. Look, if you have the time and YOU feel like it's helping then crack on and do some stretching after your workout. It won't hurt and maybe just maybe it will have some recovery benefit if done to light intensity. We'd say get some daily stretching in but at different times to your workouts and you'll likely see more benefit. It's about using your time wisely.