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Peter Stanley - My Thoughts On Two Great Coaches

  • Posted: 06.05.2013
  • Author: Peter Stanley
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My Thoughts on Two Great Coaches: Tom Tellez and Loren Seagrave.

Recently I was able to sit, listen and watch two great coaches from the USA at the European Sprints & Hurdles Conference held at Warwick University. One advocated an efficient running action by prioritising elastic energy release from the hip; the other prioritised fast recoveries of the lower leg. I was enthralled.

Initial thoughts were that these two greats were literally coming at the problem of sprinting/running fast from two opposing ends. This caused intense discussion between the attendees.

I believe we need to think about the actual action of running to analyse exactly what they were saying.

Let us start with a definition: Impulse is defined as the product of force applied over the time   by which the force is applied. This means that increasing force production and/or lengthening the time spent in force application will increase impulse.

Consider the process of maximal velocity running. When running at high speed, due to the cyclic nature of running, the duration of each ground contact is short, and the distance the centre of mass travels whilst the foot is in contact with the ground is very small in comparison to the distance of flight. The goal is to minimise the inevitable ‘braking effect’ of each contact ( yield or eccentric contraction) and allow fast stabilisation of the plant, and transfer to a quick, powerful release or take-off (concentric contraction/toe off) but this does not correlate with the length of ground contact times which allow the opportunity to generate the aforementioned impulse  The distances used in approach running for jumping are necessarily short due to energy system and coordination limitations, offering further restriction to momentum development. Impulse generation requires large force applications and long ground contact times, conditions that are clearly at odds with the high velocities that are desirable for short sprints and horizontal jumps approach runs.

When sprinting the hip extends initially while the knee and ankle stabilize; Later, as the hip continues to extend, musculature of the knee shifts from stabilizer to force generator, extending the knee and applying force through a stabilized ankle. Finally, as the hip and knee have nearly completed their extensions, the ankle contributes. Effective push-off forces during acceleration and sprinting are the result of appropriate ‘firing order’s. It follows that this ideal firing order of extension requires a certain unique amount of time, thus a certain ground contact time is prerequisite for this ideal process.

Please note this order is precisely the joint extension order we utilise in Olympic lifting and plyometric exercises.

Elastic Energy – Tom Tellez Running Drills

Muscles can create much greater forces when contractions are preceded by a pre-stretch of the muscle and its tendons. The rebounding effect that occurs creates elastically produced energy. The fact that this energy creates no metabolic fatigue,yet produces greater forces than purely concentric contractions means that the development of elastic energy is a highly desirable goal in a variety of athletic endeavors. This can be deemed to be ‘free energy’. The processes of acceleration and sprinting occur much more efficiently when elastic energy is developed. The processes associated with elastic energy gains during fast running are spinal engine function, hip oscillation and undulation of the centre of mass, and establishment of proper amplitude of motion. Oscillation produces stretches in the local musculature and connective tissue, creating great elastic energy gains. Hip oscillation also results in increased stride length without metabolic energy cost.

During running the centre of mass follows an undulating path. The low points of this curve occur during support. These periods of amortization offer opportunities for stretch shortening cycles to be developed in the pelvic stabilizing and leg extensor muscles, again producing elastic energy. Care must be taken so that the amortization process is not excessive and that foot contacts occur in the correct location, so that the undulating path of the centre of mass may be located for maximal displacement and elastic energy producing benefits.

Finally, large amplitude of motion in the hip joint, as evidenced by a long angular path of the femur, sets up elastic energy gains. Sufficient amplitude must be developed since stretches occur only near the limits of motion. To allow these movements the pelvis must be stabilized in an ideal alignment so that forces applied produce displacement without excessive distortion and rotation. However, the pelvis must be stabilized in such a way that the development of elastic energy is not impaired by restricting movement. Excessive instability and/or postural misalignment cause postural muscles to overwork to compensate for this instability and to maintain balance. This restricts their ability to function in elastic fashion.

Coaching thought:

Because of the reflexes involved, the value of technical learning exercises and drills which occur at velocities insufficient to evoke these reflexes must be questioned.

Recovery Mechanics – Loren Seagrave

The primary mechanical concern of the recovery phase is to reduce the effective radius of the recovery leg. This is accomplished by flexion at the knee joint. The degree of flexion present is a function of velocity. Shorter segments are able to generate greater angular velocity, therefore a tightly flexed knee with a high heelrecovery path are desirable at maximum velocities. During the acceleration process, velocities are submaximal, ground contact time is longer ( impulse) and recovery distances are shorter. This results in lesser degrees of knee flexion which should be observed during recovery. At maximal velocities, maximal knee flexion should be seen as the femur reaches a position perpendicular to the ground, since it is at this point that the other leg is commensurately at maximum extension.

The knee flexion seen in recovery is primarily the natural result of well- timed flexion of the hip. When the direction of the femur is changed, the prior angular momentum of the lower leg results in knee flexion. Volitional knee flexion plays a very small part. Efficient recovery assures that the next foot contact will occur in the correct location to insure stability and proper contact time. Efficient recoveries also insure that the thigh will have sufficient time to reach its proper upward range of motion, maintaining freedom of movement and elasticity in the musculature of the hip joint. (This is the same soring mechanism which I referred to earlier) However, it should be noted that poor recoveries are generally symptoms of incorrect firing orders.

Please note my comments regarding this on the previous Tom Tellez section.

As quoted earlier, improper firing orders may exist in the form of overuse or over-extension in one or more joints. Improper firing orders will cause inefficient recovery mechanics. Over-extension in the hip, knee, or ankle joint will delay toe-off and compromise stability. The recovery mechanics are corrupted and hurried in an effort to restore stability. Since toe-off has been delayed, these corrupted recovery mechanics generally take the form of delayed flexion of the knee during recovery, resulting in a lower heel recovery path. In extreme cases, there may not be enough time available to allow the knee to reach its ideal degree of flexion before preparing for the next ground contact. In either case, the compromised recovery generally results in a hip that does not flex sufficiently. Injury due to co-contractions may result, since the hip extensors may still be in contraction while the hip flexors start to contract (or vice versa). This causes severe compromise of elastic energy gains and impairs free movement in the hip joint.

 Coaching thought:

When running at speed the dynamic shapes and patterns of movement must be observed as smooth and harmonious. Any major changes in postural stability and ability to transfer momentum through the contact points will indicate weaknesses and/or co-ordination disruption.

Summary

We must observe the WHOLE pattern of movement and realise that the cyclic action of strike and recovery are dependent upon each other. We may see faults in certain sections of the pattern but we need to understand the cause and effect of what we are seeing. Drills are ideal for working on segments in isolation but that segment of the whole pattern must be re-absorbed within a harmonious pattern to reflect efficiency of the continuous movement. There is a balance to be observed which is fundamental to effective performance.

In short I believe Tom & Loren are actually telling us the same thing but they are coming at it from different ‘sides’ of the cycle. 

Regards

Peter Stanley

British Athletics Event Group Lead- Jumps

 

References : Irving ‘Boo’ Schexnayder, Tom Tellez & Loren Seagrave.     

 

 

 

 

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