Run On Softer Surfaces Or Improve Running Technique?

I read with interest two recent letters written to the Forum page in the Straits Times in the past month. One writer suggested making softer surfaces for runners at park connector paths to take care of runners' knees.

Another writer said it's not the running surface but a runner's poor running technique that causes the knee joints to wear out.

In today's Forum page, another two writers wrote in with their comments. The first writer acknowledged that both running surfaces and running technique may be the cause of knee problems. However, he thinks that excess weight may be a contributing factor too since 30 percent of 500 respondents in a survey said they had gained 5kg during the pandemic (of course there were many others who lost weight too).

The second writer, a medical doctor suggested brisk walking rather than running for joint longevity. He also said that his heathiest octogenarian patients maintain a healthy weight by being active through walking rather than pursuing 'exercise achievement goals'.

Running definitely does not wear out your knees. I've written about this before and there is so much research supporting this.

If anyone should be paranoid about running wearing out the knee joints, it should be me after 3 knee operations. The following are my personal views, backed by published articles. 

Although research has shown that there is no difference between running on the road versus grass in terms of leg inflammation, I personally feel it is much softer to run on grass or the soft sand on the beach compared to running on the pavement or road.

If you're heavier, that can put more load on the joints definitely, but running does not wear out the joints. By all means improve your running technique or do deep water running if you have to.

Be patient, increase your training load gradually, have at least one rest day a week and don't do too much too soon.

*Have a look at page A17 in today's Straits Times (270121)

Beach Running Anyone?

I have patients who get impact associated injuries like shin splints or stress fractures all the time. it's probably the most common running injury we see in our clinics along with knee pain.

Other than deep water running which has no impact, I often suggest going to the beach to get them running again.

Have you tried running on the beach? Research shows that running on sand requires 1.6 times more energy expenditure than running on a firm surface. Try it to believe it. Due to the change in technique you require as well as balancing on the sand, the stabilizing muscles in your hips, knees and ankle are working much harder.

Soft sand is particularly difficult while hard or packed sand (near the edge of the water) is definitely easier to run on. It definitely works different muscles (compared to running on the road) and it requires more focus so you don't sprain your ankle due to the uneven surface and constantly shifting ground.

In fact, while combating the "slip" element, range of motion of joint angles around the hip, knee and ankle were found to similar to running during faster speeds on firm ground (Binnie et al, 2013). That translates to a much higher heart rate, increasing your oxygen debt and blood lactate levels. Meaning you get fitter, stronger and faster quicker.

So incorporating sand running into your training can definitely help improve your race times.

Another article found that soft sandy surfaces reduced muscle soreness and fatigue (Binnie et al, 2014) due to almost four times less impact versus a firmer surface. Because of the softer surface, there's also less stress on our joints which can lessen impact and helps prevent injuries.

When running on firm ground, less of the elastic energy which is stored in our tendons is absorbed, so you don't have to work as hard. When running on sand, it absorbs the forces, meaning you have to generate more forces with your muscles to run.

Researchers found that there was almost four times less impact forces on soft sand compared to firm ground with every single foot strike. This is really good if you need to reduce load through the legs but still want to get in a hard workout when you run. 

Research also suggest that runners who ran on the beach (especially on soft dry sand found farther away from the water) had less muscle damage and inflammation compared to running on grass (Brown et al, 2017).

Due to where I stay, I hardly get to run barefoot on the beach. When I do, which is often during our family's holiday trips, I always start much slower than my usual runs. I also do not worry about the time or distance that I clock. In fact, I often do some short hard sprints (because of the lower impact) to get my heart rate up even higher.

Hearing the waves crash also helps to calm and clear my mind, which is a nice bonus.


References

Binnie MJ, Dawson B et al (2014). Effect Of Sand Versus Grass Training Surfaces During An 8-week Pre-season Conditioning Programme In Team Sport Athletes. Eur J Sp Sci. 32(14): 1001-1012. DOI: 10.1080/02640414.2013.879333.

Binnie MJ, Peeling P et al (2013). Effect Of Surface-specific Training On 20-m Sprint Performance On Sand And Grass Surfaces. J Strength Cond Research. 27(12): 3315-3520. DOI: 10.1519/JSC.0b013e31828f043f.

Brown H, Dawson B et al (2017). Sand Training: Exercise-induced Muscle Damage And Inflammatory Responses To Matched Intensity Exercise. Eur J Sp Sci. 17(6): 741-747. DOI: 10.1080/17461391.2017.1304998

Lejeune TM et al (1998). Mechanics And Energetics Of Human Locomotion On Sand. J Expt Biol. 201: 2071-2018.

Should You Run On Grass Or On The Road?

After my 3 knee operations, I was paranoid about running on any other other surface other than grass. Virtually all my run training was done on grass. Yes, you read correctly, even when it meant I had to do multiple rounds/ loops around any field I could find. Some of you reading this could probably recall seeing me going round and round the patch of grass while I was running. I thought that running on grass and its softer surface will be more gentle on my joints.

And I guess I wasn't alone thinking like this. I'm sure many of you runners out there would have met some runners, coaches etc who will swear that grass and soft running surfaces are much better. So here's a topic most runners will be keen to know. Is running on grass better than running on the road. I saw an article on this topic by some Australian researchers last week. Please read on if you wanna know more.

The runners studied did 2 runs, a 10km run at 75-80% V02 max and a 10 x 1km interval session at 90-95% V02 max. The 2 runs were done on both grass and a bitumen road surface (road). The researchers measured blood & urine samples collected before, immediately after and at 3 and 24 hours after exercise.

Here's what the researchers found. There was no difference between road & grass in terms of leg inflammation and other effects measured (if you wanna know, they measured IL-6, hemoglobin & haptoglobin levels, iron and ferritin to analyze hemolysis and hepcidin).

Hard interval training on the other hand produced more inflammation than lower intensity training.

So now you know, running surface doesn't really matter. I still prefer to run on grass or sand when I can. It definitely feels softer despite what the evidence says. 

Reference

Peeling P, Dawson B et al (2009). Training Surface and Intensity: Inflammation, Hemolysis, And Hepicidin Expression. J of Med Sci Sports Ex. 41(5) : 1138-45.

*Picture from Flickr