Saturday, February 11, 2006

Podiatry Source Journal : Agility

Agility:In sport, agility is characterised by fast feet, body coordination during change of direction and sports skill performance, and reaction time/ ability. It is an amalgam of balance, speed, strength, flexibility and coordination. Although a performer’s agility relies heavily on the acquisition of optimum sports technique, it can also be enhanced by specific conditioning.
A variety of performance-enhancing agility drills, systems and items of equipment are available to the sportsmen of today and their coaches. The ‘science’ of agility (and speed and power) training has made rapid strides recently, especially in terms of its accessibility to the mainstream sporting world.

Dissecting a sports skill
Essentially, agility training dissects a sports skill: a skill like the fast-stepping ability required of a rugby player is broken down into its constituent parts, which are then specifically trained. It’s all about patterning and conditioning a heightened physical, neural, sport-specific response.
Let’s consider in more detail the process involved in developing fast feet. One of the major tools available for this purpose is the floor-based rope ladder. This piece of kit is a key element of the Sports, Agility and Quickness system; (SAQ International is the world’s leading company for packaging and marketing sports-specific training and has been used by England’s Rugby World Cup winning squad).
A wide variety of running, hopping and jumping drills can be carried out in all directions, using the rungs of this ladder, which is laid flat on the ground. Such drills enhance foot speed and upper body agility, just like any other aspect of sports performance, by progressive overload. England rugby wing Ben Cohen has been specifically singled out as a player whose feet have been rendered especially fleet by means of extensive use of the rope ladder and other agility training methods.
Speed through a floor ladder can indicate much about a player’s quickness(1). A time of less than 2.8 seconds (male) and 3.4 seconds (female) for running the length of a 20-rung ladder, one foot in each rung at a time, is regarded as ‘excellent’ for college athletes.
Agility training also utilises numerous other drills and items of specialist kit; these include balance drills, slaloming in and out of cones and stepping over and around small hurdles. To make the transference of the agility skill even more sport-specific, an actual sports skill can also be introduced. This could take the form of dribbling a football in and out of cones, or receiving a rugby pass while stepping through a foot-ladder. More of this below.
SAQ in female footballers
Obviously, companies like SAQ International claim their systems get results and improve players’ agility. But is their confidence justified? Polman and associates looked at the effects of SAQ techniques on female footballers over a 12- week period(2). The players were divided into three groups, two performing SAQ training, while the third carried on with their normal conditioning programmes. The results were as follows:
All three interventions reduced the participants’ body mass index (-3.7%) and fat percentage (-1.7%), and increased flexibility (+14.7%) and VO2max (+ 18.4%);
However, the SAQ groups showed significantly greater benefits from their training programme than the other group on a sprint-to-fatigue test, a 25m sprint, and left and right side agility tests.
Working to improve the agility of a dynamic sports performer (like a footballer or rugby player) by means of SAQ and similar techniques seems highly appropriate, relevant and valuable. But will the same principles apply to endurance athletes? After all, quick-as-a-flash agility is not a prerequisite for triathlon or marathon running.
Alricsson and associates carried out a study to evaluate whether dance training had any effect on the joint mobility and muscle flexibility of the spine, hip and ankle and on the speed and agility of young cross-country skiers. Cross-country skiing is a not a sport renowned for quick dynamic movement, but shaving seconds off on every turn and jump could add up to significant time savings. Dance training was selected for this task because of its potential contribution to agility and flexibility.
The study involved 20 élite cross-country skiers, aged 12-15, with half of them (five girls and five boys) receiving weekly dance training and the rest serving as non-dancing controls for a period of eight months. Joint mobility and muscle flexibility of the spine, hip and ankle were measured before the study period and at three and eight months. Two sport-related functional tests Рa slalom test and a hurdle test were carried out at the same times.
The researchers found that the dance group had increased their speed by a total of 0.3 seconds over the slalom test after eight months. They also improved their speed and agility on the hurdle test by 0.8 seconds after three months and by a further 0.6 seconds after eight months. Furthermore, they increased flexion-extension of the thoracic (upper) spine by 7.5° after three months and by a further 1.5° after eight months, while lateral flexion improved by 0.04mm and a further 0.03mm over the same periods. Meanwhile, the non-dancing controls did not show any improvements in any of the studied variables.
Effects of dance training
Alricsson concluded: ‘Dance training has a positive effect on speed and agility and on joint mobility and muscle flexibility in flexion-extension and lateral flexion of the spine in young crosscountry skiers’. Had his subjects made use of more sport-specific agility training, the chances are that their gains would have been even greater.
Marathon runners do not have to dart sideways, backwards and forwards with lightning speed over the course of their 26-mile effort, so could they have anything to gain from agility training? To answer this question, we need to consider the interplay between agility and power training.
Research indicates that, despite prolonged running training, runners’ leg muscles may not actually be that efficient at returning energy to the running surface. In fact, at certain speeds these muscles may be working at only 50% efficiency because of the ‘natural’ energy return effectiveness of the foot arch and Achilles tendon.
It’s a bit like having an engine turbocharger that works in reverse. Your Achilles and foot arch are the turbo: they cut in automatically when your foot strikes the ground, producing a burst of power but leave the running muscles (quads, hamstrings and calf muscles – the engine) working at less than their full potential. Unless you target these running muscles with specific power conditioning drills, your ability to drive up running speed can be compromised.
Such exercises as hopping on and off of a low box and spring jogging (virtually straight leg movements, where the performer propels himself forwards primarily by means of feet and ankles) not only develop ‘harder’, and therefore more effective, running muscles through their plyometric effect, but also improve agility.
Plyometric exercises enable muscles to generate huge amounts of force in a split second, when a concentric (shortening) muscular contraction immediately follows an eccentric (lengthening) contraction of the same muscle. These agility and power moves can ‘sharpen’ foot/ground contact and result in a more economical and powerful running stride, regardless of running distance.
Backwards and sideways running can also ‘prehabilitate’ against injury, providing a further reason why endurance runners (and those involved in running-based sports) should perform agility training.
As mentioned above, conditioning exercises, such as a plyometric drills, can develop both agility and power. However, these drills may not exactly match what is required in a playing situation. To ensure they do, it is essential for coaches to analyse in real detail the agility and movement patterns required for their sport and to use this information to construct the most relevant conditioning programme. In this respect foot positioning can be crucial.
Kovacs and associates looked at the relevance of foot positioning, particularly foot-landing positions, in athletes performing plyometric depth jumps drills involving stepping off a box then immediately springing upwards, sideways or forwards(5). Specifically, the researchers were interested in comparing the force generated by flat-footed and forefoot ground contacts.
Ten male university students performed two types of depth jump from a 0.4m high box placed 1m from the centre of a force plate. They were instructed to land either on the balls of their feet, without the heels touching the ground, or on their heels. The researchers discovered that the two different jumping styles generated force in very different ways. Using specific measuring equipment, Kovacs’ team demonstrated that a forefoot landing depth jump produced significantly more power at impact and at the transition into the jump than a flat-footed landing depth jump.
Depth jumps and power
Kovacs’ findings have crucial implications for optimum agility and power conditioning. Even though a flat-footed-landing depth jump will develop power, this may not channel optimally into enhancing the agility and power of a player in a specific sport. For example, a sprinter would probably benefit more from forefoot-landing jumps, as the sprint action is performed from a similar foot-strike position, whereas a basketball or volleyball player is likely to develop greater vertical spring – a key requirement of the games – by using flat-footed landings. Muscle firing patterns are very specific, and conditioning drills must mirror sports skills for optimum results.
Finally here’s an example of an even more specific agility/power conditioning drill, designed for a tennis player. The player should perform a depth jump with a forefoot – but non-aligned – landing position, which will enable him or her to rotate and sprint, in 3-5 strides, to a designated target to the left or right.
This drill mimics and conditions the typical agility (power and speed) required in a game situation – eg to reach a drop shot. And it can be made even more specific if the player holds a racket and ‘ghosts’ a shot on reaching the designated target.
In summary, if you or those you coach want to become faster, more elusive, more efficient and more dynamic in their movements, it is advisable to incorporate specific drills into regular training routines.

John Shepherd Peak Performance Magazine

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