Since the 1956 Olympic Games, when the Soviet race walkers emerged as a force in the sport, there has been an evolution in the technique as faster athletes began to start the stride by landing with the foot closer to the center of gravity than their predecessors. Although this technique factor is only one of many explanations for the improved times, it nevertheless warrants a closer investigation.
To discover the optimum landing position in race walking it will be necessary to determine which groups of muscles produce the most powerful thrust at the different phases of the stride sequence. A practical observation can be made by adopting a double-support position at normal walk stride length and apply the following forces:
It will be observed that by "pulling" from the front leg only, the muscle groups are not strong enough to move the body. The thrust from the rear leg easily moves the bodyforward, and a combination of both forces appears to result in the rear leg doing the bulk of the work, with the front force providing stabilising assistance.
This simple test indicates that the muscles used to push from directly under the center of gravity to the lift-off stage of the stride, should be the forces used by a racewalker for as much as possible in each stride. Of course, other factors, such as momentum, body lean, and ankle flex must, of course, be considered.
It is possible while walking to concentrate on the "feelings" in the muscle groups as they come into action. By altering the position of the landing position of the front leg the athlete can feel the extra effort involved when the leg is extended to the front and the easier mode of progression caused by it landing under the body.
Further, by adopting the stationary double support phase position, it is possible to observe the options open to a walker in relation to the landing (heel strike) posture. By"sitting" back with the weight on the rear leg, the front leg extends in front of the centre of gravity. By "rolling" forward over the front foot, it can be positioned directly under the centre of gravity.
Steven I. Subotnik in his Functional Anatomy divides the race walking gait into the swing and the double support phases, making active use of the following muscle groups:
Studies have shown that the major drive in a race walking stride is generated from the muscle groups in the lower limb as they take over from the stride sequence initiating muscle groups above the knee. The posterior superficial muscle group is active throughout most of the double-support phase of the gait, ceasing its activity just before the toe-off. The deep posterior (flexors) group, consisting of the flexor hallucis longus, is active virtually from the contact until the final push-off. This group also takes over at the final stages of the propulsion when the posterior group has finished its activity.
The lateral group is active during both mid-stance and the propulsion phases. The posterior deep and lateral groups are therefore primarily active during the double support phase. The anterior tibial, extensor hallucis longis, and extensor digitorum longus are active both during the end of the double support phase and the propulsion, while the medial plantar group works from the middle of the double support phase to the liftoff.
The muscle groups active during the first 15 percent of the entire cycle are assisting in decelerating the plantar flexion of the forefoot, as it approaches the support surface. These muscles also stabilise the rear foot at the initial heel strike. Observing the muscles being used in the mid-stance and the push-off stage (20 to 50% of the stride sequence) reveals that the largest combination of the lower limb muscles are active during this stage. Only the anterior group is idle.
Further support can be obtained from a paper titled "A Biomechanical Analysis of Race Walking Gait" by Cairns, Burdett, Piscoita and Simon, who produced a series of graphs on the ground-reaction forces, showing the same results as Subotnik. It confirms that the major forces are applied from the position when the leg is under the athlete's centre of gravity until the toe-off.
Suzuki, Norimatsu and Chibs' studies into the role of the lower limb muscles in the race walking gait made the following observation: "The decreased vertical component of the propulsive force in race walking appears related to changes in the anterior-posterior force. The transition from posteriorly to anteriorly directed force occurs early in race walking, at 30% to 40% of the stance."
They also note that "the more recent force platform/cinematographical studies indicate that the maximum decelerative forces occur when the supporting foot is still in front of the athletes body, and may be attributable to overstriding by the athlete." These findings suggest that the optimum foot landing position would be directly under the centre of gravity. However, this author believes that taking into account the momentum factor, it would not be a disadvantage to place the foot up to 30cm in front of the center of gravity when landing in this position. The delay from anterior to posterior force would be counteracted by the walker's momentum, carrying the body over the centre of gravity.
Most of the world's fastest walkers appear to be using a technique that places the leading foot within 20cm from the centre of gravity and drive back from the hip to attain the desired long stride.
Recent field tests at the Australian Institute of Sport measured the distance between the leading foot and the centre of gravity of a group of walkers, including David Smith, Simon Baker, Kerry Saxby, and Andrew Jachno. The results showed that these walkers landed between 30.5cm and 42.8cm in front of their centre of gravity. The walkers with the fastest times at the time of the test were the closest to the centre of gravity. The summary of these tests included a paragraph which stated that the technique used to increase the stride length was unexpected. "The walkers decreased the distance their feet made contact with the ground, while they increased their drive and stride length."
The walker should therefore aim for a technique with a 3 to 5 degree forward lean that assists the foot strike close to the centre of gravity. Using a vertical and horizontal hip movement to lengthen the stride allows the athlete to exploit the strongest muscle groups of the lower limbs and allows for a fast recovery of the anterior muscle group to attain the heel strike.
The strongest part of a race walker's drive is from the time the foot flattens until the ball of the foot loses contact with the ground. It follows therefore that the quicker a walker reaches this phase of the stride, the faster will be the mode of progress. By landing with the lead foot close to, or under the centre of gravity, the walker achieves this aim.
Finally, it is advisable to use a role model in the teaching of this technique. After observing the action, the walker is asked to jog along at a pace of approximately five minutes a kilometre and gradually change to a straight-leg landing. Faults are then corrected. Experience has shown that an explanation alone is not satisfactory, as the action is too fast for the neuro-muscular coordination. Faster results can be obtained with the jogging-straight leg method.
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