Plyometric exercises are usually thought of as being jumping exercises. In reality any exercise that takes advantage of the stretch shortening cycle is plyometric in nature.
The stretch shortening cycle refers to movements that involve a rapid eccentric (muscle lengthening) phase immediately followed by a rapid concentric (muscle shortening) phase. The stretch shortening cycle increases the potential for force production. This is because connective tissues such as tendons and ligaments store elastic energy during the rapid eccentric phase. If the concentric part of the movement immediately follows the eccentric phase then this elastic energy is released, allowing for greater force production. If there is a pause before the concentric phase starts then the stored elastic energy is lost, and cannot be released to allow for increased force production.
The requirements for increased force production through stretch shortening cycle activity are:
1) a rapid eccentric (muscle lengthening) phase
2) an immediate transition from the eccentric phase to the concentric (muscle shortening) phase
Sprinting involves a high level of stretch shortening cycle activity. The muscles of the lower limb rapidly lengthen as they absorb the impact of ground contact upon initial foot strike. In order to keep the ground contact time to a minimum there is a very quick transition from the eccentric phase of the movement to the propulsive concentric portion.
Many people assume that jumping exercises need to be included in the training program in order to overload the stretch shortening cycle. Whilst it is true that traditional weight training methods will not directly improve the ability to generate force through the use of the stretch shortening cycle, this is not true of Olympic Weightlifting.
When performed correctly, a phenomenon known as the double knee bend occurs with lifts such as the clean and the snatch. The initial knee extension that takes place when lifting the weight from the floor results in a rapid lengthening of the hamstrings. The knee then 're-bends' as the lifter makes the transition into the second pull from the mid thigh, resulting in a rapid shortening of the hamstrings and lengthening of the quadriceps. As the second pull takes place there is a triple extension of the hip, knee and ankle joints resulting in a shortening of the major leg muscles. This is followed by a rapid lengthening of the same muscles as the athlete drops under the bar in order to receive it at the shoulders or overhead in the catch position.
As you can see, if the correct lifting technique is used there is a series of stretch shortening cycles that take place when performing lifts such as the clean and the snatch. This makes these lifts far more applicable to improving sprinting performance than just about any other weight training method.
In summary, the stretch shortening cycle is of great importance to sprinting since it allows greater force to be produced during the ground contact phase. Traditional weight training methods only improve force production ability as result of adaptation to the neuromuscular system. Traditional plyometric activity (jumping exercises) primarily results in an improved ability to use the stretch shortening cycle. Olympic Weightlifting results in adaptation to both the neuromuscular system and the connective tissues affecting the stretch shortening cycle. For this reason Olympic Weightlifting techniques should be included in the training programmes of all sprinters.
(Tim Egerton)
The stretch shortening cycle refers to movements that involve a rapid eccentric (muscle lengthening) phase immediately followed by a rapid concentric (muscle shortening) phase. The stretch shortening cycle increases the potential for force production. This is because connective tissues such as tendons and ligaments store elastic energy during the rapid eccentric phase. If the concentric part of the movement immediately follows the eccentric phase then this elastic energy is released, allowing for greater force production. If there is a pause before the concentric phase starts then the stored elastic energy is lost, and cannot be released to allow for increased force production.
The requirements for increased force production through stretch shortening cycle activity are:
1) a rapid eccentric (muscle lengthening) phase
2) an immediate transition from the eccentric phase to the concentric (muscle shortening) phase
Sprinting involves a high level of stretch shortening cycle activity. The muscles of the lower limb rapidly lengthen as they absorb the impact of ground contact upon initial foot strike. In order to keep the ground contact time to a minimum there is a very quick transition from the eccentric phase of the movement to the propulsive concentric portion.
Many people assume that jumping exercises need to be included in the training program in order to overload the stretch shortening cycle. Whilst it is true that traditional weight training methods will not directly improve the ability to generate force through the use of the stretch shortening cycle, this is not true of Olympic Weightlifting.
When performed correctly, a phenomenon known as the double knee bend occurs with lifts such as the clean and the snatch. The initial knee extension that takes place when lifting the weight from the floor results in a rapid lengthening of the hamstrings. The knee then 're-bends' as the lifter makes the transition into the second pull from the mid thigh, resulting in a rapid shortening of the hamstrings and lengthening of the quadriceps. As the second pull takes place there is a triple extension of the hip, knee and ankle joints resulting in a shortening of the major leg muscles. This is followed by a rapid lengthening of the same muscles as the athlete drops under the bar in order to receive it at the shoulders or overhead in the catch position.
As you can see, if the correct lifting technique is used there is a series of stretch shortening cycles that take place when performing lifts such as the clean and the snatch. This makes these lifts far more applicable to improving sprinting performance than just about any other weight training method.
In summary, the stretch shortening cycle is of great importance to sprinting since it allows greater force to be produced during the ground contact phase. Traditional weight training methods only improve force production ability as result of adaptation to the neuromuscular system. Traditional plyometric activity (jumping exercises) primarily results in an improved ability to use the stretch shortening cycle. Olympic Weightlifting results in adaptation to both the neuromuscular system and the connective tissues affecting the stretch shortening cycle. For this reason Olympic Weightlifting techniques should be included in the training programmes of all sprinters.
No comments:
Post a Comment