Inspiring Sports Technology
Rugby
Under Armour release new Wales away rugby shirt
Thursday, September 2nd, 2010
Well, Well Under Armour are venturing into outerwear using similar technology. A nice design with Under Armour’s Heatgear fabric, 4-way stretch and “Dragon” scale grip pattern.
Canterbury Zygo boot imitates finger prints!
Thursday, September 2nd, 2010
Canterbury of New Zealand have released a boot upper technology that looks like a finger print. According to Canterbury claim:
“Zygo is a unique boot technology that increases kicking distance, power and imparts more spin on to a ball. Specially developed pods are positioned on the front to improve control and on the side to improve grip. The pods are specifically formulated to reduce energy loss in the interaction between boot and ball, this allows the ball to leave the foot with greater speed”
The boots retail for circa £120.
Why is the 2007 RWC ball under so much criticism?
Thursday, September 2nd, 2010
Although the overall number of successful kicks appears to be consistent with previous Rugby World Cup tournaments, there has been significant media attention surrounding the flight of the Rugby World Cup ball, developed by GILBERT™. Originally instigated by reaction from the players, particularly Jonny Wilkinson and Dan Carter, problems that may cause missed conversions include over-inflation and wear and tear. So is there any truth in what the players or manufacturers say?
The explanation for perceived differences depend on which view, the players or the manufacturers, you care to believe. Jonny Wilkinson, in an interview prior to the semi-final match against France, said “It’s important for the kickers because you want to be in as much control as you can. However, it’s impossible to tell how it will go. I have no idea what happens after the ball leaves my foot. I can only go on how the ball feels coming off my foot. A few kicks have surprised me by going wide but a few others have surprised me because they went over in this tournament”. Players, particularly Jonny, are known to train daily; kicking numerous punts, drop-kicks and conversions. The repeatability of player performance has yet to be quantified; however it is certain that professional kickers have an expert opinion on ball performance. Perception is influenced by mood, health and feeling however concerns have been ranged in a number of matches reducing these effects. So, if we believe the players point of view, then ball material and construction must be at fault. Yet, GILBERT™ have conducted numerous player and mechanical tests to show that its flight characteristics are similar to previous balls, namely the Xact® used in 2003 RWC. If you believe the manufacturer’s opinion is correct then environmental characteristics must cause the irregular flight, such as air density and viscosity in the stadium, and wind velocity. This may be true but we must consider all possibilities. Is it over-inflation, under-inflation, grip pattern, panel pattern, weave anisotropy, bladder material, shell material, stitching design or strength, out-of-balance forces, vibration characteristics, etc?
Of course, the design characteristics and construction of the bladder, grip pattern and laminate material are top secret however from recent research we can begin to understand the flight of the ball. The following suggestions and hypothesis are written to cause further discussion. Firstly, it is impossible for a player to repeatedly strike the ball at the same point, speed, and accuracy every time, otherwise all kicks would be converted; indeed we must consider human error as a possible cause. If in fact, the difference can be attributed to over-inflation, then we must consider why the balls are over-inflated. England claims that the ball for their opening match was pressurised to 10.5 psi rather than the optimum 9.5 psi. Over-inflation will change ball performance however there is little published literature in this area, particularly for rugby ball flight. It has been suggested that an under-inflated ball will travel further but is more difficult to aim and an over-inflated ball is harder to kick but easier to aim. This human-error by the officials was supposedly rectified for the rest of the tournament. From video analysis, kicks appear to veer to the right and left of the posts. Therefore ball spin and aerodynamics must be another cause, which can be affected by stitch and panel design as well as “still” air in the stadium. Alternatively, assuming the ball uses a poly-cotton weave construction, fabric anisotropy may be the reason for off-centre ball flight. Although studies of the grip pattern have been shown to improve handling characteristics, it is unlikely that the pattern will significantly affect aerodynamics. Pimple height is relatively small compared to overall ball geometry; which is not the case in golf ball design.
Perhaps water retention may be the cause although GILBERT™ claims this has been improved. It has been shown that added moisture, therefore added mass, reduces the distance kicked. Out-of-balance forces are also caused by water retention and valve placement altering ball spin. If we believe that GILBERT™ are aiming to optimise ball design for true-flight, then we may consider the possibility that kickers are used to poorer performing balls and that they have designed their kicking technique to suit.
So, what is the reason? Unfortunately from current literature it is not possible to give an exact answer. Few have studied the aerodynamics of rugby balls on the field-of-play, few have studied the mechanical properties of ball materials in flight, few can track a rugby ball in flight to determine spin rates, few understand the mechanisms of friction, few understand the handling characteristics, few can quantify the repeatability of ball strike, few understand vibration in ball impacts, and so on. Perhaps computer modelling and advancements in testing methods will provide us with answers and we can only hope that manufacturers develop further understanding of the mechanisms of ball flight on the field of play.
Who tackles (hits) harder – American Footballers or Rugby players?
Friday, August 27th, 2010
So you want to know who tackles harder – rugby players or american football players? Well this video certainly provides some insight. Have a look!
