Lower limb injuries and long distance running.. let’s blame pronation

One of the most common problems with long distance running is the recurrence of lower limb injuries. By ‘lower limb’ I’m talking about the stuff that goes on below the knee and this includes (but not exclusively):

1. Achilles problems
2. Shin Splints (front or rear)
3. Plantar Fasciitis (pain under the foot / heel)

Overuse injuries are created by repeated action, hence they are common in long distance runners. In some circumstances, runners may have bio-mechanical faults which make them more susceptible to overuse injuries. In other cases, it’s simply a matter of doing too much and the tissues just can’t handle the load. Perhaps the most commonly cited reason for injury in runners in ‘over-pronation’, this describes the action of the foot landing on the outside of the heel and then rolling both forwards and inwards onto the big toe. Pronation has been blamed so frequently for running injuries that we now have specific shoes and various inserts to prevent the action, but is pronation receiving unnecessary criticism?

Pronation explained

The vast majority of runners pronate to some extent when they run. If you stand with your feet hip distance apart and then start walking, you’ll notice that you don’t walk with your feet hip distance apart. It is natural to walk and run with your foot directly underneath the centre line of your body (if you draw a line from your nose, through your belly button and down to the floor, that’s where you foot will land). This means that your leg is always at a slight angle, starting at your hip, the leg angles inwards to the point of foot strike and this means that you are likely to hit with the outside of your heel.

At the point of impact, the force applied to the outside of your heel ‘flips’ your shoe (and your foot) inwards. Stand holding a running show and with your hand, strike the underside of the heel on the outside edge. The blow will flip the shoe inwards, this is what happens to your foot each time you strike the ground.

Injuries linked to pronation

As your foot flips inwards, this triggers the pronation movement. In an attempt to control both the amount and speed of pronation, there are some specific muscles  which take the majority of the strain. The tibialis posterior and anterior muscles run along the length of your shin bone. The anterior muscle is found on the front of your shin and the posterior muscle is found on the inside of the lower leg, behind the shin bone. You can generally find both quite easily with your fingers. The tendons from each pass over the inside of your ankle joint (look at the boney lump on the inside of your ankle, if you move your foot about, you’ll see the tendon moving on the boney lump).

When these 2 muscles contract, they pull up the arch of the foot and turn the ankle so the sole of the foot faces inwards, this is the opposite movement to pronation. Their main job is to control the pronation movement and as the foot rolls inwards, they are pulling back in the opposite direction to reduce and slow the pronation movement. For this reason, if your foot pronates excessively, these muscles have to work extremely hard and this may lead to inflammation of the muscle or the tendon (the tendon is the white part which attaches the muscle to the done). Inflammation of these muscles is commonly referred to as shin splints or potentially ‘compartment syndrome’.

The pronation movement can also lead to achilles problems. Generally the achilles is pretty strong when it pulls in correctly alignment, unfortunately pronation causes the achilles to twist, as if ‘wringing it out’ and this leads to damage and inflammation. Pronation can also lead to flattening of the arch and this applies stress to the tissues which are supporting the arch. one of the main structures supporting the arch is the plantar fascia, a tendon which runs from the underside of the heel bone to the forefoot, splitting into the 5 toes. If stress is applied to the plantar fascia, it can start to pull away from the underside of the heel bone, leading to a sharp pain known as plantar fasciitis.

So pronation is bad.. right?

There are various problems which are ‘potentially associated’ with pronation and these are often treated with a change of shoes or orthotic insert when they may well have been resolved with some rehab (strength and stretch). However, pronation is not a bio-mechnical fault, it is an important part of your running which has simply received a lot of bad press. Before you rush out and buy inserts for your shoes, contrary to what you might think from reading the above information, pronation can be your friend if you know how to handle it.. we’ll look at that in part 2 of the sequel.

Regards
Marc Laithwaite
www.theendurancestore.com
www.theendurancecoach.com

Hoka Mafate, a serious distance running contender!!

The Hoka Mafate looks a little odd. In fact, that’s a lie.. it looks VERY odd. The size of the cushioned sole and the bright colours will be the reason why many people will never try this shoe, let alone purchase a pair. It’s looks will potentially be the biggest stumbling block at point of sale.. and that is a real shame, because this shoe is well worth your attention.

You may think that the amount of cushioning means this shoe is as far from bare foot as you can possibly get. I’ve heard plenty of comments regarding Hoka shoes and how they are going against the bare foot trend but this couldn’t be more untrue. The Hoka has only a 4mm differential (drop from heel to forefoot – see previous barefoot running post to read more), making this a real forefoot running shoe. In fact, it has the lowest differential of all shoes in the store! I recently ran in a trial pair and was immediately struck bow how much I naturally moved onto my forefoot and refrained from heel striking.

Bare Foot V Minimalist

One of the problems which exists is how to define a ‘bare foot shoe’. A low differential (4mm Mafate) is key for enabling runners to land on their forefoot and reap the associated benefits, the problem is that many shoes attain the low differential by reducing the amount of cushioning in the sole of the shoe. In simple terms, most barefoot / forefoot shoes have no cushioning and whilst they encourage a more natural run style, the impact damage caused whilst running long distance can be severe. I noticed a significant reduction in ‘soreness’ following long runs in the Mafate, compared to my other shoes. This difference in ‘soreness’ can only be attributed to reduced muscle impact damage, by lessening the pounding.

Stability

One look at the Mafate often generates one common response.. you’ll twist your ankle as soon as you run on rough terrain! Having ran in them, this isn’t the case. I wouldn’t choose them for rocky fell races, but that’s not why they were designed. The shoe is so soft that as you run on uneven surfaces, the sole moulds around stones and rocks and ‘smooths out’ the terrain, therby making them pretty stable. On long, hard packed trails, there would not be any issues whatsoever with stability.

Downhill

This is where the fun really starts.. whilst they would not be the shoe of choice on very rocky fell races, downhill on relatively good trails are an absolute pleasure. The heel has huge amounts of cushioning, coupled with a rocker which rolls you forwards onto the forefoot following the heel strike. There is no harsh braking, no slapping feet on even the steepest tracks and no painful jarring through the legs and knees. The shoes are massively quicker than normal footwear in this situation, a fact which I have proved recently running with friends who found the ease and speed with which I ran downhill almost laughable.

The Verdict

If you can get past the look of these shoes, they really are worth a try. If you suffer impact related problems in the knees and hips which prevent you doing longer runs, they are definitely worth a try! Call in the shop to try them on the treadmill and check your running technique: www.theendurancestore.com

The check out the Mafate go here: http://www.theendurancestore.com/section.php/151/1/hoka-trail-shoes

Regards
The Endurance Store

Warm up, strength and injury prevention..

Foot Strike Science teamed up with Adam Smith, to produce a series of videos for warming up, preventing injury and developing run specific core strength. Adam is a chartered physio who has worked as a strength and conditioning advisor at elite level in sport. Amongst his employers are England Rugby Union, New Zealand All Blacks and Australia Rugby League. Adam’s current interest is ultra distance trail running and he’s entered in the Montane Lakeland 50, July 2012. Adam will be contributing to our blogs and working to develop Foot Strike Science, based at The Endurance Store.

This warm up routine is a simple sequence of exercises which can be completed before running. Complete the lunge routine as 5 repetitions per lunge (5 forwards, 5 side etc), complete 5 sequences of the hand walk and 10 of the upper and lower body rotations.

The strength routine should be completed twice per week, following a run session. Start with 1×10 repetitions progressing to 2×10 after 2-4 weeks. For single leg squats start with 1×5 and progress to 2×8.

The core routine should be completed ideally 3 times per week, holding static exercises for 30 seconds+ with good form and completing twice each. For alternate legs and vertical legs (last 2 exercise) start with 2×10 and progress.

The injury prevention routine should be completed ideally 3 times per week. The hip thrust and bridge exercises should be completed 2×10 progressing to 3×10 after 2-4 weeks, all others 1×10 progressing to 2×10.

The flexibility routine should be completed following each run session, stretches should be completed 3 times each for 30 seconds.

Get into your stride.. but make it shorter and faster!

There are 3 simple principles which we believe to be the fundamental requirements of successful running, these are the 3 C’s: Core, Contact and Cadence. We’ve already discussed core and contact in previous blogs, to complete the trio, this blog will focus upon Cadence.

What is cadence?

Cadence refers to your stride rate, which is the speed at which you move your feet! Cadence can be measured as ‘strides or foot strikes per minute’ and is generally counted on one single side (either right or left) as this represents a full leg cycle. In simple terms when you run, count how many times your right foot only hits the ground in a minute (you can use the left if you prefer!), but don’t count both left and right foot strikes simultaneously or you will effectively double your cadence. There aren’t many runners who know their own cadence, but it is a simple thing to measure at any time during your training run. There is little scientific research relating to running cadence, but 90 strides per minute appears to be the agreed optimal speed. Generally as we become tired, our cadence will slow, but stride length (how far we travel per stride) stays the same, this reduction is cadence causes us to slow down.

Stride Rate V Stride Length

The simple relationship between stride rate and length is that a faster stride rate is generally accompanied by a shorter stride length. By comparison, a longer stride length is generally accompanied by a slower cadence (short fast strides or long slow ones..). It is a common assumption that to improve your running you need to ‘lengthen your stride’, this would potentially be accompanied by a slower cadence. This does not necessarily lead to a decrease in running speed, a slightly longer stride compensates for the slightly slower cadence and running speed may stay the same. It makes perfect sense that going quicker can be achieved in two simple ways:

1. Keep your stride length the same but increase cadence (move your legs faster)
2. Maintain the same cadence but increase your stride length (go a bit further each stride)

There are benefits of a slower cadence, it will generally lead to a lower heart rate and oxygen consumption which is helpful if you’re tired. Faster cadences tend to increase your heart rate and oxygen consumption, which places more physiological strain upon your body.

Interestingly, when we get tired our stride length tends not to change a great deal. The first thing to change is our cadence, we move our legs slower and slower. Sometimes runners will attempt to stride even further than normal, allowing the cadence to slow as a compensation. For this reason, when you’re tired during a race, maintaining a quick cadence should be your main focus..

Heel Strike V Forefoot Running

We mentioned above that there are 2 ways to go faster:

1. Keep your stride length the same but increase cadence (move your legs faster)
2. Maintain the same cadence but increase your stride length (go a bit further each stride)

Whilst it may initially seem like both are valid options, we need to examine the impact of stride length upon foot strike before recommending either technique!

As you increase / lengthen your stride length there are a number of consequences:

1. At the point of foot strike, the knee becomes increasingly extended (less knee bend/flex)
2. The point of impact moves progressively from forefoot to heel strike
3. The foot strikes the ground further ahead of the body
4. The braking effect at point of impact becomes progressively greater

Running with a shorter stride length ensures that you minimise each of the above 4 points and for this reason, a shorter stride length is more economical and efficient. However, as outlined earlier, a shorter stride length coupled with faster cadence also leads to a higher heart rate and oxygen consumption (not economical). Whilst shorter cadence may be ‘biomechanically’ more efficient, when coupled with the necessary faster cadence, it may well be ‘physiologically’ less efficient. To counteract the physiological negatives, the faster cadence must be practiced at all times, irrelevant of training speed. During long slow distance runs, the cadence should be at 90, this can be achieved by shortening the stride.

As with any new technique, it requires practice and there will be an initial phase during which it will feel uncomfortable, unnatural and uneconomical. Ultimately you should feel that these changes encourage forefoot running and the natural bounce discussed in our previous blog.

Go forwards, run tall, run firm and run forefoot..

Put your best forefoot forwards.. are you a bouncer or a muscler?

Minimal contact time..

My old running coach used to say ‘run as if you’re on hot coals’, which I later found out was also a quote from the film Chariots of Fire. They were the words chosen by Sam Mussabini, the coach to Harold Abrahams. What Mussabini knew is that contact time slows you down, the more time you spend in contact with the floor, the longer it’ll take you to reach the finish line.

The camera never lies..

Look at the race photos from any event, start with the winners then move to the back of the field. The faster runners will generally only have a small part of either foot in contact with the ground and often when pictured, both feet are off the ground as though they are levitating (if you ever find a picture of yourself with both feet off the ground, be sure to buy it, they generally don’t come along that often). If you run a marathon and you’re lucky enough to get a series of photos taken at various points throughout the course.. it’s interesting to compare the set and see if things change, it’s possible to go from levitating in the early miles, to having both feet fully on the ground in the last of the sequence. It should be noted that technically.. that’s not counted as running!

Foot contact and energy return..

It is wrong to think that when fast runners hit the ground, the calf muscle contracts to propel them forwards at the ‘toe off’ point. The calf muscle itself doesn’t do a great deal, it contracts ‘isometrically’ or in a ‘static’ manner (it doesn’t change length). The propulsion is generated by a stretch of the achilles and other tendons, which store ‘elastic’ energy and then recoil, allowing the runner to spring forwards. It’s important to understand that this ‘elastic bounce’ can’t be generated unless you land on the forefoot.

Practical task: Stay in one spot and bounce on the balls of your feet, swap to land on your heels and try to bounce.. that’ll probably do the trick right there and you’ll appreciate why forefoot landing is important for ‘elastic bounce’ or ‘energy return’.

A little bit of tendon physiology which might make you faster..

Elastin is a protein found within tendons and it gives them the ability to stretch, store energy and then recoil to propel you forwards. For this reason, tendons are very different to ligaments, which don’t stretch and help to stabilise joints. One of the issues relating to the ageing runner is the manner in which elastin degrades and loses it’s ability to store elastic energy. This is one of the major reasons why runners slow down as they get older. Tendon elasticity also varies from person to person and is simply part of your genetic make up. It’s also been shown to vary geographically, East Africans have thinner and longer achilles tendons and its been suggested that this makes them return energy more effectively.

What happens if you can’t bounce?

If your tendons don’t stretch and store energy, you have to find another way to propel yourself forwards. This generally involves using muscle tissue to literally ‘muscle yourself’ forwards and as a result you use a lot of oxygen. The unfortunate outcome of using so much oxygen is that you get tired very quickly and run slower.. that’s not good.

How do you bounce?? Yep.. thought you might ask that..

1. Forefoot running is important and your running technique determines whether that will happen
2. The shoes you wear might not allow you to forefoot strike, so check that out
3. Simple plyometric exercises will help, start with the bouncing on the spot I mentioned earlier just to get the feel
4. You need a firm chassis so the core stuff mentioned in the previous blog is essential, if you hit the ground and everything collapses.. forget it..

Regards
The Endurance Store

Mizuno Wave Ascend 6, Trial and Report..

I’ve had the Mizuno Wave Ascend 6 for a couple of weeks (following a Facebook recommendation!) and have ran in them most days. As an inov8 fan, I was a little sceptical at first as I thought that it might be a ‘token trail shoe’ from Mizuno who are otherwise focused primarily on the road market. It’s a great fit and very comfortable straight out of the box and didn’t take any ‘breaking in’. It’s relatively lightweight and has a great feel upon impact. The differential (see barefoot running post for further explanation of differential) is slightly greater than some of the inov8 and other ‘fell shoes’ but being a forefoot runner, I didn’t feel at all that this shoes forced me onto my heels.

I’ve mainly been running of local footpaths, but this morning I’ve been out on the Lakeland fells for an hour and a half and I was concerned that the grip and the stability would not be great, as this is technically a ‘trail shoe’ as opposed to an all out ‘fell shoe’. You can see from the sole that it has been widened slightly to give greater stability on rough ground and it never once felt unstable on tussocks, rocks or any other surface. The grip was very effective and on the descents I slowly gained confidence and eventually felt as though I was descending at the same speed that I would in any other pure ‘fell’ shoe.

I’d have to admit that I wouldn’t wear these shoes in a short fell race, I’d go for my X-Talons every time as they are lighter and lower with a more aggressive tread. However, for longer runs, the Mizuno shoes are fantastic and I’m happy to say that I’d now prefer them for longer stuff than my Inov8 295 or 319. I am a convert and very glad for the Facebook recommendation..

If you’re doing longer trail or fell stuff and looking for a great all rounder, this is definitely a shoe to consider..

Call in and try them on the treadmill, GO HERE NOW

Core stability and running performance..

You can’t produce power from an unstable platform and for this reason the ability to stabilise your pelvis, spine and torso whilst running play a large role in your performance. You can waste a lot of energy if your postural muscles have to work hard to hold everything in place and stop things moving around excessively. One of the common issues with runners is core collapse at the point of foot impact. Watching runners in slow motion is a great way to spot this problem and usually manifests itself in a significant amount of pelvis movement and collapse in the mid-section as the foot strikes the ground.

What is correct running technique?

Your pelvis, spine and torso should be tall, in alignment and you should have a slight forwards lean from the ankles (not bending forwards from the waist!) You can trigger this by picking a stop 10-15m ahead of you on the floor. The reason for the slight forwards lean is to shift weight onto the forefoot rather than the heel and allow gravity to help you move forwards. Next time you run, try a slight forwards lean and see how it affects running, then lean backwards and you’ll feel the brakes kick in immediately.

Avoid pushing the pelvis forwards or sticking out your chest as this creates an inward arching lower back which impacts on both your breathing and your foot strike, from the side view, everything should be in alignment from heels to head with a very slight forwards lean.

Should I do core exercises and will it help my running?

Doing core exercises in the gym will not necessarily impact upon your running technique, it must be practiced whilst you run. Doing core exercises in the gym will help you to hold the correct running posture, but  will not simply lead to a change in running technique. The best way to train your postural running muscles is to run with the perfect posture..

Go forwards, run tall, run firm and run forefoot..

Barefoot running, the basics explained..

Bare foot running is a real trend at the moment, but what exactly does it represent and why are some shoes considered bare foot and others aren’t?

The structure of your running shoes can offer some added benefits, to keep it simple, we’ll focus on 3 main functions:

1. Support – the shoe may be designed to stop your foot rolling inwards excessively (pronation shoes) or they may not have this function (neutral shoes).

2. Cushioning – some shoes have a great deal more cushioning in the heel and forefoot to absorb impact, this tends to be more the case for road running shoes.

3. Drop – refers the difference in height between your heel and forefoot. If you look at your shoes from a ‘side on’ view, there tends to be a thicker wedge of cushioning under the heel than under the forefoot. This means that when you stand in those shoes, your heels are a little higher / further from the ground than your toes (termed a planter flexed ankle position).

For the time being, lets not worry about the support and cushioning as these are the 2 most commonly discussed functions. If we are focusing on barefoot style, it’s the ‘drop’ which is most significant.

What’s the most economical way to run?

Running economy is a simple measurement of ‘miles per gallon’ for athletes and is defined simply as how much oxygen you require to run at a given speed. Generally as fitness improves, your economy improves and all speeds just get easier.

Which tissues do we use for running?

There are 2 main things which we use to propel ourselves forwards, the first is muscular contraction (which requires oxygen) and the second is elasticity in tendons which to some extent act like coiled springs, store energy upon impact and then propel us forwards.

Tendon elasticity

It is thought that both tendon stiffness and elasticity are largely responsible for our running economy. If our tendons act like coiled springs, store energy upon foot strike then ‘recoil’ to propel us forwards, we don’t need to use the muscles as much. Muscles use oxygen and tendons don’t.. so economy improves. In simple terms, if we bounce, we don’t need to use muscles to ‘mechanically run’.

Where does barefoot come into it?

To generate this ‘coiled spring bounce’ elite runners are more likely to land on their forefoot and as they do so, the heel will be slightly ‘off the ground’. At this point the heel will drop, stretching the achilles, which then acts like a coiled spring storing energy. As the achilles then ‘recoils’ the runner is propelled forwards.. this type of elastic action is sometimes termed ‘plyometric’.

Shoes classed as ‘barefoot’ style have less ‘drop’, meaning that your heel and forefoot are the same height from the ground. Consider the description of running above, if at the point when your forefoot hits the ground, there is a large wedge underneath your heel, this makes it impossible for the heel to drop, the achilles to stretch and the runner to generate ‘energy return’ for propulsion. This is what tends to happen if your shoes have significant drop (heel higher than forefoot). The heel has nowhere to go, it can’t drop and stretch the achilles and it has a 3 inch foam wedge underneath.

What does it mean for me?

It is fair to presume that shoes which have a greater drop (thicker heel cushioning) are more likely to promote heel striking, which eliminates any elastic energy from the achilles or knee mechnism. This will not always be the case and running style, in particular stride length and cadence will have an impact upon your foot strike. Whether you forefoot or heel strike will also impact upon whether you pronate and ‘how you pronate’, which adds more complication to the whole story..

To conclude, depending upon your running style, barefoot shoes may be better for you and lead to enhanced economy. Be wary of potential dangers – this extra strain placed on your achilles, calf and lower leg muscles can lead to problems if you do not give yourself the opportunity to adapt progressively. Seek advice!

Regards
The Endurance Store
Appley Bridge
Wigan
WN6 9AE

Influence of the muscle–tendon unit’s mechanical and morphological properties on running economy. The Journal of Experimental Biology 209, 3345-3357

Changes in tendon stiffness and running economy in highly trained distance runners. Eur J Appl Physiol (2010) 110:1037–1046