Slumped posture (rounded back), ‘sit in a bucket’ posture.
Arm action is not coordinated with the legs. Arms swing across the body, causing rotation. Arm drive is from the elbows (arms bend and straighten), not from the shoulders.
Knee is driven high, not forward.
Ankle does not come under the buttocks in a straight line but comes out to the side as it passes under the body.
The leg reaches as it comes into the ground so that overstriding occurs (ground is contacted too far in front of the centre of mass).
Toes are pointed in flight so that the child con- tacts the ground with the toes first.
accelerates the body forward. In high-speed running or sprinting, maintaining this position isn’t possible, but the aim is to keep the centre of mass over the ground contact point as much as possible. In distance running, in which the velocity of movement is much less, this forward lean isn’t necessarily a consideration until the athlete needs to accelerate for a sprint finish. At more energy-sparing paces, the athlete tends to adopt a more upright running posture.
The speed of movement also typically influences the nature of the ground contact. In sprinting, much of the foot surface should contact the ground (enabling a large surface area through which to generate ground reac- tion force) without the athlete’s heel making contact. The practitioner leading the technical development programme should be conscious of the coaching cues provided to the young athlete. ‘On your toes’, for example, is a com- monly used coaching term, as is ‘on the balls of your feet’. In reality, both of these cues encourage the child to use a part of the foot with small surface areas to contact the ground, reducing the potential for forceful ground contact. Analogies such as the credit card rule—‘I always want to be able to get just a credit card between your heels and the ground when you run’—may be more appropriate for developing the foot contact into the ground.
At slower running speeds, when the efforts are submaximal in terms of speeds, not car- diovascular effort, ground contact is usually different and similar to the walking action. The athlete typically contacts the ground with the heel first, rotates through a flat-foot position at midstance phase and then onto the forefoot for toe-off. This heel-to-toe action is considered more energy sparing and absorbs more ground reaction forces, which is important when multiple foot contacts occur in longer-distance running.
In adults, for example, the transition from walking to running generally occurs at a speed of 2.3 metres per second to make locomotion more efficient. At 2.5 metres per second, the stride rate increases by 44 per cent over that seen in walking, and the stride length increases by 15 per cent as the flight phase becomes more pronounced. Increased flexion occurs at
the knees and hip joints, and flexion continues to increase with the velocity of movement.10
A common error is ‘sitting in a bucket’ (i.e., sticking the hips backwards and leaning for- ward from the trunk). This posture is usually most evident as an inefficient athlete changes speed. Ground reaction forces aren’t optimized because hip drive is limited, and forces are not effectively transferred through an object or structure that isn’t straight. Similarly, a rounded shoulder position in the forward lean is often seen in younger athletes. This posture detracts from the optimum sagittal plane shoulder drive and should therefore be discouraged. Activities such as overhead medicine ball marching or overhead stick running (figure 8.7) are excellent postural activities for correcting this practice.
The opposite arm and leg forward action, with a fast, short arm movement throughout, should be maintained. A leg action that is not coordinated with the arms will result in a clumsy, nonfluid movement that will have visible rotations in the transverse plane. As the lead leg moves forwards, the knee should drive forwards as the foot leaves the ground. Simulta- neously, the ankle dorsiflexes, so that the knees are pulled towards the toes in flight. The greater the running speed is, the closer the ankle should be towards the buttocks to enable a rapid rota- tion underneath the body. This transition from rear-side mechanics (from midstance through push-off to the drive leg passing underneath the body) to front-side mechanics (the lead leg accelerates towards the floor to ground contact) should be smooth, and an active transfer of weight should occur between the legs through an unsupported flight phase. The ankle should remain dorsiflexed during the flight, ground preparation and ground contact phases.
The knee and ankle movements during this action are common sources of error in young athletes. For example, as the athlete prepares for ground contact, the toe may be pointed towards the floor (the ankle is plantarflexed). The toe then makes ground contact, meaning that the movement is inefficient. Subsequently, the muscle actions of the gluteus maximus and calf muscle complex are liable to be inhibited.
The forward movement of the knee is also important. The knee should be driven forward
Figure 8.7 Postural running drills such as (a) the overhead medicine ball march and (b) overhead stick
runs are excellent means to encouraging sound postural mechanics.
with the ankle pulled towards the buttocks rather than driven high. Typically, the high knee action changes the athlete’s body lean from one slightly forward to upright or even rear- wards, especially with athletes who have tight hamstrings and overactive hip flexor muscles. Some traditional coaching drills, such as butt kicks and high knees, develop inappropriate knee positions that do not benefit the athlete in high-velocity running. Although these drills are often touted as useful dynamic stretching activ- ities, practitioners can use alternative means of achieving these stretches without developing inappropriate running responses in athletes.