Robin Saunders is a British Athletics Federation Senior Coach (UK Athletics Levei 4) in 100m, 200m and 4xW0m reiay. He is based at the University of East Anglia in Norwich and is currently working with novice sprinters and athletes returning to sport Mowing a long absence. In this article. Robin discusses a stride pattern necessary to the driving phase of a WOm sprint performance. In a recent coaching paper written for this journal, “Five components of the 100m sprint” (see Modern Athlete and Coach, 42,4), I listed each discrete component of the 100m performance, in the required order of execution, as being: a fast, reactive response to a given stimulus; an efficient block clearance; tfie powerful drive to full acceleration; maintenance of horizontal velocity; and, reluctant but relaxed deceleration. It is the third of these components, the powerful drive to full acceleration through an effective, mechanically correct technique with which we are primarily concerned in this paper, although it should be understood by both coach and athlete that a competent execution of each discrete component is crucial to the overall integrity of the sprint performance both in competition and in training. However, it has long been apparent to this author that the novice or developing sprinter seldom achieves maximum attainable velocity in a 100m sprint performance, a fact which is borne out by the apparent inconsistency of the sprint performance times recorded by young athletes over a wide range of abilities. The powerful drive to achieve full acceleration in a 100m sprint is accomplished through a learned technique which Dick (1991) among others, has identified as the Sprint Drive, The Sprint Drive technique should be regarded primarily as a vehicle through which the athlete is enabled to achieve full horizontal velocity in the execution of a technically competent sprint performance, in the 100m sprint performance, it is essential ttiat the athlete accelerates to maximum velocity in as short a time as possible. This said, it should be appreciated that, the greater the maximum velocity potential of a sprinter, the further the distance in metres it will take to achieve in performance. For instance, although an elite sprinter is likely to attain maximal velocity between 50-60m, a weaker rate of acceleration combined with a lower potential for maximal velocity would suggest that a novice performer requires a much shorter distance to achieve his/her maximum horizontal speed.
The Sprint Drive component of the 100m sprint performance commences as the athlete is moving out of a “pike” body position, through a powerful horizontal thrust from the starting blocks. At this initial point in the driving phase, the back is flat and the centre of mass is low in order to overcome friction and inertial forces in the initial strides of the sprint performance. The head is in line with the torso and the eyes are looking down at the track in order to prevent the driving athlete from rising too soon to an upright position. The arms are driven back through a full range of movement in a vigorous pumping action that reflects the powerful driving action of the legs. The elbows should be held at an approximate angle of 90 degrees as they are driven back to a position high behind the torso to counterbalance the low, forward position of the head and shoulders. An emphasis should be placed on work performed behind the body, with the powerful, backward sweep of the arms more pronounced as the hands pass behind the hips and the legs driving to full hip, knee, and ankle extension behind and below the torso before the completion of each foot contact with the track. Accordingly, the duration of each foot-strike will be comparatively long in the opening strides of the Sprint Drive phase, as the athlete strives to increase the rate of acceleration towards maximum attainable velocity. Knee-lift must be comparatively high in relation to the low torso as the athlete, in rising gradually from a low body position, strives to step over the ankle of the opposite foot in order to facilitate a brief, but increasing period of flight in each successive stride. With the force of friction being steadily overcome and the rate of acceleration increasing, the athlete is able to raise the torso slowly to a more upright position, with the eyes focussed directly ahead and beyond the distant finishing-line. Foot contact with the track will become lighter and the duration of each foot-strike, the amortization phase of each stride, will become less as the rate of acceleration increases through the driving component of the sprint performance. The emphasis on work performed behind the body must continue until maximum velocity is achieved and full running height is apparent. In a proficient sprinter, these two features will be seen to occur without abrupt changes in posture. With the athlete in an upright sprinting posture, the emphasis on work will now be distributed equally in front of and behind the body: high knee lift, with hands rising to chest height in front, with high elbows complementing full extension of hip, knee and ankle of the driving leg behind. At this point in the performance, the Sprint Drive technique may be seen to have accomplished its objective as a vehicle by which the athlete is able to attain full horizontal velocity. As with the learning of any technique, rehearsal of each aspect of the Sprint Drive should be undertaken at appropriate intervals, with meticulous attention to detail by the coach, and with the training status and ability of each athlete clearly in mind. However, I feel there Is one major point relevant to the teaching of the Sprint Drive technique to novice sprinters which is frequently overlooked by the inexperienced coach. This concerns the relationship between stride rate and stride length during the Sprint Drive phase of the 100m performance in what McFarlane (2000) has described as a stride pattern of pure acceleration. In order to attain full horizontal speed as quickly as possible, it is crucial that, in the early strides ot Uie Sprint Drive as much tlight as possible is eliminated from the sprinting action. The initial stride should be as short as practicable, with the athlete aiming to make an initial foot contact with the track within 50cm of the start line. Each subsequent stride should then be increased in length by approximately 10cm until optimal stride length is reached as the athlete rises to an upright postute and approaches maximum horizontal velocity.
The principle behind the stride pattem of pure acceleration applies to both novice and elite sprinter, of course. However, in this paper I would first tike to use as an example an improving sprinter who has a good level of flexibility and a mechanically sound sprinting technique and who invariably completes a 100m performance in around 50 strides which, of course, requires an average stride length of approximately two metres. Simple test controls and regular monitoring of our subject sprinter’s performance in competition indicates that he has an optimal stride length of 2.30m while sprinting at full horizontal velocity. Clearly, not all strides in tlie 100m performance will measure 2.30m, which is the apparent maximal efficient stride length of our subject sprinter, nor will each stride measure the estimated average length of two metres. If the initial stride is to be completed within 50cm of the start-line, some strides clearly are going to be longer than others! In tfie execution of the Sprint Drive technique by a developing sprinter, it is advisable that successive strides increase by approximately 10cm as a brief period of flight is added in the completion of each stride. If the initial foot contact with the track occurs within 50cm of the start line, the next stride should ideally measure 60cm followed by subsequent strides of 70cm, 80cm and so on until optimal stride length is attained. In our example, if the maximal efficient stride is to measure 2.30cm, this will occur on completion of the nineteenth stride. At this point, as the athlete achieves an upright posture and approaches maximum horizontal velocity with an approximate stride length of 2.30m at the conclusion of the Sprint Drive phase, s/he will have reached a distance approximately 27 metres from the start line.The remaining 73 metres of the sprint performance, should the athlete maintain an optimal stride length of 2.30m, will be completed in a slightly more than thirty two strides, that is, during the recovery phase of the fifty first stride. These statistics, then, support the earlier observation that our subject sprinter invariably completes the 100m distance in approximately fifty strides. In contrast to the elite sprinter, who may still be accelerating between the 50-60m points of the 100m performance, the developing sprinter is likely to reach maximum horizontal velocity between 35*45m, depending on ability and experience. Accordingly, the stride pattern of the more accomplished and more powerful elite sprinter is likely to be based on an increasing stride length of 15cm, with the initial strides measuring 60cm, 75cm, 90cm etc up to an optimal stride length of perhaps 2.50m. In this example, the elite sprinter will be capable of approaching a maximal efficient stride length in fourteen strides on completion of the opening 22m of the 100m distance as s/he approaches maximal horizontal velocity. The remaining 78m of the sprint performance, if the athlete were able to maintain an optimal stride length of approximately 2.50m would be completed in a further thirty two strides, that is, on completion of the forty sixth stride. Close scrutiny over a number of years of a wide number of elite sprinters has convinced this author that the above statistics are accurate and reliable and that the given stride pattern of pure acceleration is a necessary tool in the technical armoury of any efficient sprinter. Rehearsal of this stride pattern should be carried out regularly in each athlete’s training programme using a simple method of sticks being placed on the track at a distance appropriate to his/her training status and ability. Each athlete shouid be asked to accelerate through a maximum of eight sticks engaging a technique appropriate to the Sprint Drive as described eariier in this paper. In the development of his/her own technical ability, the athlete should be encouraged to ‘feel’ the increasing length of subsequent strides by replicating the Sprint Drive technique over ten to twelve strides in the absence of marker sticks. Unless the stride pattern of pure acceleration which underiies the Sprint Drive technique is addressed regulariy in a training situation and the technique accomplished in a competitive situation, it is unlikely that consistency will be achieved in performance nor full potential as a sprinter maximised. it is imperative to the development of the athlete, then, that the coach emphasises the value of the stride pattem of pure acceleration as a vehicle by which the athlete is enabled to increase the potential for maximal horizontal velocity in the performance of the 100m sprint in Ijaining and in competition.
References:
Dick. Frank W. (1991). Sprints and Reiays. BAAB.
McFarlane, B. (2000). The Science of Hurdling and Speed. Athletics Canada.
Saunders, R. (2004) Five components of Uie 100m sprint Modern Athlete and Coach (42,4).