Sunday, May 16, 2021

Does Dynamic Stretches Help Running Performance?


Our new physios doing the dynamic stretches

Previously I had written that performing any static stretches before exercise or competition can be detrimental to your athletic performance. Studies have also shown that doing static stretches before competing or exercising is more likely to cause an injury. In fact, performing just one static stretch of 30 seconds can reduce your maximum strength.

Meanwhile, fitness professionals, coaches and other studies have suggested performing dynamic stretches as an alternative warm up to static stretches instead.

Well, this published study had runners do both. An initial assessment was done to get the runners VO2 max levels. The researchers had a group of well trained university runners do a general warm up (GWU) on one day versus doing a general warmup (GWU) plus dynamic stretching (DS) before getting them to run until exhaustion on a treadmill on another day.

The GWU consisted of running on the treadmill at a speed equivalent to 70 percent of each runner's VO2 max for 15 minutes. Each runner then did a standing rest for 5 minutes. This was followed by the run to exhaustion on the treadmill at a speed equivalent to 90 percent of their VO2 max. 

When doing the GWU plus DS, dynamic stretches were done for all the lower limb muscle groups (10 reps each), see picture below. That took 3 min 45 seconds in all. After resting for 1 min 15 seconds, the runners started their run to exhaustion on the treadmill at a speed equivalent to 90 percent of their VO2 max. 

Well, this published study had runners do both. An initial assessment was done to get the runners VO2 max levels. The researchers had a group of well trained university runners do a general warm up (GWU) on one day versus doing a general warmup (GWU) plus dynamic stretching (DS) before getting them to run until exhaustion on a treadmill on another day.

The GWU consisted of running on the treadmill at a speed equivalent to 70 percent of each runner's VO2 max for 15 minutes. Each runner then did a standing rest for 5 minutes. This was followed by the run to exhaustion on the treadmill at a speed equivalent to 90 percent of their VO2 max. 

When doing the GWU plus DS, dynamic stretches were done for all the lower limb muscle groups (10 reps each), see picture at the top. That took 3 min 45 seconds in all. After resting for 1 min 15 seconds, the runners started their run to exhaustion on the treadmill at a speed equivalent to 90 percent of their VO2 max. 

The results showed that the GWU plus DS group lasted significantly shorter (10:40 min)  than the group that just did the GWU (12:40 min). Distance covered was between 2.3 to 5.4 km.

The authors of this study were hypothesizing that performing GWU plus DS may help improve endurance running performance. Unfortunately the results indicated otherwise. 

Another study by the first 3 authors (Yamaguchi et al, 2015) showed that performing the same five DS (10 reps) followed by a rest period of 1 min 23 secs actually prolonged the run time to exhaustion (an extra 18.2 percent) compared to a sit down rest. Run to exhaustion on the treadmill was also done at a speed equivalent to 90 percent of their VO2 max.

What is good about this study was that there was real attention to detail. The testing was done during the off season for the runners so no prior vigorous training was done. The runners were also asked to avoid performing intense exercises or training on each test day and the day prior. 

The runners were also instructed to have similar meals and drinks on the test days and previous day and to finish any meal 2 hours before running. Runners were also asked to avoid alcohol the day before running and caffeine on the test day. Each runner wore the same attire for the test runs and performed the test at the same time of day in consideration to circadian rhythm. The laboratory temperature was kept constant at 20-24 degrees Celsius throughout. In short, the authors tried to keep everything else constant other than the warm up. 

What wasn't as good? Bear in mind that the study only had 8 runners. They are definitely fast runners (looking at their profile), but the sample size is small. The rest period after the dynamic warmup was also extremely short (150 seconds). Fatigue after the DS was attributed by the authors as the cause for worse performance.

When I was competing in events like 1500m - 5000m on the track, I'll do a rather languid jog of 2-3 km to warm up followed by some limbering movements to loosen up. This was followed by repeating some striding (or goal pace running) 5-8 times for 150-200 meters. Then it would be resting and waiting for our event to start. Definitely longer than 1 minute 15 seconds before racing. Definitely did not do any sort of stretching then.

My advice would be to try out dynamic stretches or whatever that is new (shoes, bike, run technique etc) in your off season, not before an important competition, to see if it would be something that might work for your body. Most importantly, do what works for you. Every body is different.

References

Yamaguchi T, Takizawab K, Keisuke S. (2015). Acute Effect Of Dynamic Stretching On Endurance Running Performance In Well-trained Male Runners. J Strg Cond Resc. 29: 3045-3052. DOI:10.1519/JSC.0000000000000969

Yamaguchi T, Takizawab K, Keisuke S et al (2019). Effect Of General Warm-up plus Dynamic Stretching On Endurance Performance In Well-trained Runners. Res Quart Ex and Sport. 90(4): 527-533. DOI: 10.1080/02701367.2019.1630700.

*thanks to Thiviyan and Rashid Aziz for getting me the articles

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