No, these words were not from a Donald Trump rally: they’re not “Fake News” or “Alternative Facts”, but the results of proper experimental research (see Reference for link to fully refereed academic paper in reputable journal).
Seems like a big claim, so would require good evidence to back it up. With three groups of 8 runners selected at random for each group, one being a control group, this appears a piece of robust research, albeit all runners were male. The experiment only lasted 12 weeks with 3 runs per week. Two groups added two plyomentrics session per week, after the 4 weeks of running : one group did squat jumps and one did drop / depth jumps, typically 6 minutes of exercise (6 sets of 1 minute of jumps = 30s active, 30s recovery). A pre-plyos 5k was done by all, and another after the 12 weeks of training. The control group improved by nearly 5 seconds; the two plyometrics groups improved by 140 seconds (squat jumps) and 170 seconds (depth jumps)! And they were all around mid-20's to upper-20's minute 5K runners. This is an enormous improvement in only 12 weeks, so what's going on here?
As you probably aware, I don't believe in "Silver Bullets", or anecdotal evidence, but is this too good to be true? Well, let's have a think of the physiology of running and what happens to our bodies when we run, i.e. the biokinetics. You may think running is pretty simple. When we run, we land on the ground and our leg muscles propel us and forwards. But hold on, there's more going on. When we land on the ground much of the kinetic energy is absorbed by our tendons, especially the Achilles, acting a bit like a spring, and when we push off the ground again, much of the force into the ground comes from that stored energy. And as we run faster that biokinteic energy becomes more important.
To increase our running speed we can only increase our cadence (steps per minute) our stride length, or both. Now cadence can be improved, and I have written about that before (link: https://www.cirencesterac.com/post/the-need-for-speed-too ), but most significant speed increase comes from increased stride length. Now the first thing to bear in mind is that we don't want to overstride, i.e. get our foot anding in front of our centre of mass (think hips) as we'll actually be braking, and probably injure ouselves eventually. What we need to do is get more force into the ground so we fly through the air further and faster (we don't want to spend more time in the air). To get more force into the ground through strength and by having stronger and longer tendons. A bit like elastic bands (this a good analogy), a longer fatter elastic band can store more energy than a shorter thinner band.
How do plyometrics help? Firstly, plyometrics involve a significan amount of jumping. Extensive plyometrics involve small impacts, e.g. skipping; whereas, intensive plyometrics involve greater impacts, e.g. single leg bounds, and bigger jumps. Performing jumps obviously increases leg strength, but depth jumps are effectively jumping off a box and landing, so are eccentric exercises not concentric. This results in a strnegthening of the tendons, especially Achilles, and the plantar (see picture).
I can hear some people saying, oh, I'd injure myself doing depth jumps, but they only jumped off 18" (a tad higher than my couch), which is probably only about twice as high as the squat jumpers managed. I typically do depth jumps off 30" plus (up to 42") and I'm in my mid '60's. I do higher jumps, usually not in trainers. but just socks, as my sprinting and jumping (long jump and triple jump, just for fun!) requires handling higher forces than endurance running and so they help build the strength to stabilise my body under significant loading.
The groups doing plyometrics undoubtedly developed strength in their leg muscles, but more importantly increased the elasticity in their tendons, by making them stronger. This gave them more spring when running, greatly increasing their stride length and speed. It's interesting that the plyometrics had such an impact, because of the "Principle of Specificity" in training would suggest that running is the best form of exercise for running, and it is, but all three groups did exactly the same running sessions. The plyometrics were additional sessions, not replacements. But because they build underpinning strength (physcial condition) they enabled the runners to get more from the running session than those not doing the plyometrics.
So if you want to improve your PB for 5k or increase your % for Parkrun, why not do a couple of plyometric session a week. You could do them before a couple of your runs, because they are unlikely to fatigue you such that you mess up your running. If interested, please contact me, so that you can get the best out of them for your current situation.
Dorian
Reference:
Effects of plyometric training on the performance of 5-km road runners, by ALEXANDRE FERNANDES MACHADO(1), JULIANA BRANDÃO PINTO DE CASTRO(2), DANILO SALES BOCALINI(3), AYLTON JOSÉ FIGUEIRA JUNIOR(4), RODOLFO DE ALKMIM MOREIRA NUNES(5), RODRIGO GOMES DE SOUZA VALE(6)
1,4 Postgraduate Program in Physical Education, São Judas Tadeu University, São Paulo, SP, BRAZIL
2,5,6 Postgraduate Program in Exercise and Sport Sciences, Rio de Janeiro State University, Rio de Janeiro, RJ, BRAZIL
3Laboratory of Experimental Physiology and Biochemistry, Center for Physical Education and Sports, Federal University of Espírito Santo, Vitória, ES, BRAZIL
6 Laboratory of Exercise Physiology, Estácio de Sá University, Cabo Frio, RJ, BRAZIL
Published in the Journal of Physical Education and Sport ® (JPES), 19(1), Art.99, pp. 691 - 695, 2019 online ISSN: 2247 - 806X; p-ISSN: 2247 – 8051; ISSN - L = 2247 - 8051 © JPES
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