Article by Ian Griffiths
Whilst typing up my last post a few obvious things occurred to me with respect to the relationship between runners and their trainers…
(1) We all buy them
(2) We all accept they will set us back £65 and upwards
(3) If we are honest we often wonder why they are so expensive
(4) The more little initials and words on our shoes must mean we are getting our moneys worth
There is no doubt running shoe technology continues to improve and the research that companies put into their manufacture in the current day is vast. But what does it all mean? What do these initials on your shoes stand for, and should you care?
I once again choose Asics as my example for this blog, as they are my personal shoe of choice. They have been developing shoes for over 50 years now, the Japanese winner of the 1951 Boston Marathon doing so in a time of 2:27 whilst wearing the Tiger sports shoe (Asics at the time were called Onitsuka Tiger – the Asics name was born later in 1977 following a merger).
In the current day Asics are at the forefront of innovation and work in close collaboration with athletes and specialists at their research centre in Kobe, Japan. Their scientific approach has created some revolutionary shoe designs and features, of which descriptions can often be found peppered over their shoes. Here, is a brief run down of what they all mean.
Asics footwear technology ‘for dummies’:
AHAR/AHAR+
‘Asics High Abrasion Resistance’. This is a tough rubber compound used at the heel region of the outsole to reduce excessive wear at this heavy contact area. AHAR+ is a slightly thinner and lighter version. In my opinion this may be a bit of marketing hype. I have seen plenty of other different road running shoes over the years and very few excessively wear in this area. In addition I’m sure many use similar materials, but have not ‘labelled’ it as something which sounds a bit sexier. I certainly wouldn’t cry into my cornflakes if I purchased a new pair of Asics and it didn’t have AHAR or AHAR+.
DUOMAX
A proprietary ASICS system that consists of a dual density midsole. (Two different densities designed to address foot motion). Usually easily identified as the darker grey region on the inside of the midsole. This is something you will want to look for if you run in any shoes other than neutral/cushioned shoes (it is not found in those). Far from being a gimmick this is thought to contribute to the deceleration of pronation, which may be very significant in injury prevention in individuals who have certain foot types (the more mobile/flexible and ‘flatter’ feet).
I.G.S
‘Impact Guidance System’. This is Asics trademark shoe design technology/philosophy which is constructed in a way to enhance ‘natural gait’. IGS componentry aims to help attenuate shock at heel contact via the rearfoot GEL systems, and ‘guide’ the foot safely into midstance. It is very difficult to find a mid-high range Asics which does not have this incorporated into it, and as far as I can tell it is an all encompassing/umbrella term for the entire shoe design. I am yet to see any scientific evidence or research as to how it achieves what it says it will.
P.H.F
‘Personal Heel Fit’. Special high density foam construction around the heel counter which hugs the contours of the wearer’s heel, but returns to its original shape when not being worn. Vast improvements in decreased shoe slippage noted with this technology. Now this is something I would never be without. The difference in comfort is profound. My advice – never ever buy an Asics road running shoe without PHF. It is worth every penny.
TRUSSTIC SYSTEM
This is the lightweight stabilisation unit integrated in the midsole which links the rearfoot and the forefoot. This helps maintain torsional stability of the shoe. The more recent space trusstic system is suspended below the midsole which forms a pocket (or ‘space’) into which the shoe midsole can deform. This controlled deformation, which occurs in response to the loading of the foot, results in reduced pressure on the plantar fascia. This will in turn promote a more efficient windlass mechanism – see here for more on this.
*here to link to: www.asicsamerica.com/asicstech/windlass_mechanics.htm
SpEVA/SOLYTE
My previous blog discussed the differences between SpEVA and Solyte. In addition to this, it should be understood that these midsoles come in 3 different densities, which are identified by different colours.
SpEVA/SOLYTE 45 is identified by its blue colour (beneath the sockliner of the trainer). It is more flexible, provides a high degree of cushioning and compliments the I.G.S and shock absorption properties in the neutral/cushioned range.
SpEVA/SOLYTE 55 is identified by its yellow colour and is a little more resilient, helping to boost the spring rate of the shoe. (Usually used in the stability shoe range).
SpEVA/SOLYTE 65 is identified by its red colour and limits midsole deformation. It therefore enhances support and offers a heavy runner a very stable platform. (Usually used in the motion control shoe range).
For more on the midsole lasting see here (www.asics.com.au/technology13.asp)
ASICS GENDER SPECIFICITY
Asics first realised that women run differently in 1977 when it was the first brand to introduce a women specific shoe (the ‘Tigress’). Research has shown the differences between male and female athletes; different body shapes (e.g. pelvic width) and foot function cause biomechanical differences which can affect performance and potentially the risk of lower limb injury.
Of most interest is the suggested link between the hormone oestrogen and the risk of tendon and ligament injury. It is thought that fluctuating levels of oestrogen (during various phases of a women’s menstrual cycle) can possibly alter arch height and thus predispose an individual to injury, and Asics are the first brand as far as I am aware to consider this when manufacturing gender specific shoes. The Women’s space trusstic (denoted by the W’s on the inside of the trusstic) has more ‘space’ than the men’s (denoted by M’s on the trusstic) thus accommodating the variation in arch height and resulting in greater comfort and performance for the female athlete.
