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Κυριακή 12 Δεκεμβρίου 2010

High Vertical Jump in Volleyball


ΠΗΓΗ : www.volleycountry.com

volleyball-squatOne of the facts of life in volleyball success is improved vertical jump. To get this done discussion between the volleyball and strength coach plays a key role. In the weight room three major tools are in the arsenal of every strength coach.


1) jump training/plyometrics
2) the Olympic-style explosive lifts such as the power pull
3) king of exercises, the squat and its variations.
But before you sit down and have "the talk" it's important to consider some additional factors beyond these training methods that should guide your conversation.

One important consideration is one vs. two legged training. In volleyball it is common to see vertical jump, double-leg takeoffs used frequently; and they are often the rule. The main difference would be found in an offensive slide attack where the middle attacker will adopt a more one-legged style of plant-and-jump. So is it advisable to do exercises single and/or double-legged?

jump-marshallThe next topic of conversation is the components of the vertical jump and an agreement on what they are. The muscles of the hips, knees, and ankles acting in a rapid fashion and with great force to allow the body to achieve the greatest vertical velocity as it leaves the ground. The components that come into play that contribute to the overall height of a jump include, but are not limited to: absolute/limit strength, rate of force development, relative strength, eccentric strength, stretch-shortening cycle ability, physical maturity, body composition, and technique/coordination. Do you both agree on this?

Next topic is jump styles of the players. Based on observation, there are two different types of jumping styles. The first type is a strength jumper who relies mostly on absolute or limits strength qualities and usually involves greater force development. Strength jumpers may also be built with shorter limbs and thicker joints or may have a heavier and more muscular build. Nonetheless, they use their structure and their strength to their advantage and usually will jump greater heights off two legs. These individuals will often spend greater time on the ground (>250ms) after they plant before they start the overcoming/push-off phase of their jump. This longer ground contact time will often help enhance the jump height for strength jumpers because it will become more mechanical and rely mostly on concentric power via voluntary force production.

The second type of jumpers is the elastic or reactive jumpers and is named this way because they rely on more plyometric capabilities of movement. This person will usually have greater speed in their approach or in their countermovement (in a block). These athletes also usually have very short tran¬sition/coupling times between downward and upward movements as they are more efficient taking advantage of stretch-shortening cycle actions (elastic energy utilization or stretch reflex contribution). Thus, their ground contact times (<250ms) will often be less. The elastic jumpers will often possess longer limbs, longer tendons (especially the Achilles Tendon) and small joints. These athletes will usually bend much less at their knee but may bend more at the waist (by "hinging" at the hip joint) with the center of gravity out in front. In addition, these types of jumpers will often make jumping look effortless and will appear to be bouncy or springy when they land and take-off. Based on these styles, training methods vary.
That's the talk-agreement of the components of the vertical jump, identification of jumping style of each player and the training program individualized to the need of each player based on one vs. two legged training using the various training methods available in the weight room.
Author: Ken Kontor, avca.org