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SBA 206 Spor Biyomekaniği

Dikey Sıçramanın Biyomekaniği23 Mart 2009

Murat Çilli

Biyomekanik >> Newton Hareket Yasaları >> III. Hareket Yasası

• Herhangi bir etkiye karşı her zaman bir tepki vardır; yada iki cismin karşılıklı etkisi daima eşit fakat zıt özelliktedir.

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Segment Hareket açısal Hız[derece/s]

Trunk extension: vertical jump 170Knee extension: vertical jump 800Ankle extension: vertical jump 860Wrist flexion: baseball pitching 1000Radio/ulnar pronation: tennis serve 1400

Hareket Hız [m/s]

Bar in a bench press 0.25Muscle shortening 0.5Walking 1.1–1.8 Vertical jump 2.3Free throw 7.0 Sprinting 12.0Tennis forehand 20.0Batting 31.3Soccer kick 35.0 Baseball pitch 45.1Tennis serve 62.6Golf drive 66.0

Kolların sıçramada etkisi

- +CM height at takeoff (m) 0.9296 0.9639CM vertical velocity at takeoff (m/s) 2.5095 2.7213Maximum CM height after takeoff (m) 1.2506 1.3413Total contact duration (s) 0.4344 0.5831Ankle joint work (N-m) 104.2856 96.8006Knee joint work (N-m) 104.8377 86.2193Hip joint work (N-m) 163.3235 239.6418Shoulder joint work (N-m) N/A 54.7499Work done during contact (N-m) 372.4469 477.4116

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A muscle consists of an active force generating component and a parallel connective tissue component.

This connective tissue does not actively generate force but if it is stretched beyond its resting length it acts just like a rubber band and produces a passive, elastic force.

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Parellel elastic componentThe component of a muscle that provides resistive tension when a muscle is passively stretched. The parallel elastic component is non-contractile and consists of the muscle membranes, which lie parallel to the muscle fibres. Along with the series elastic component, this component enables muscle to stretch and recoil in a time-dependent fashion.

Series elastic componentA non-contractile component of muscle that lies in series with muscle fibres. Series elastic components store energy when stretched and make a major contribution to the elastic of the human skeleton. Tendons are the major representatives of the series elastic component, but the cross bridges between actin and myosin may also contribute.

the force the muscle can create decreases with increasing velocity of shortening (concentric actions)

Force–Velocity Relationship

force the muscle can resist increases with increasing velocity of lengthening (eccentric actions).

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Force–Length Relationship

Peak muscle force can be generated when there are the most cross-bridges. This is called resting length (Lo

Active muscle tension decreases for shorter or longer muscle lengths

Passive tension increases very slowly near Lo butdramatically increases as the muscle is elongated.

The total tension potential of the muscle is the sum ofthe active and passive components of tension.

Length/Tension curve [Winter 1990]

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Force–Time Relationship

The time from the motor action potential to the rise or peak in muscle tension.

Recall that the contraction dynamics of different fiber types was about 20 ms for FG and 120 ms for SO fibers.

In fast and high-force movements the neuromuscular system can be trained to rapidly increase (down to about 20 ms)muscle stimulation.

STRETCH-SHORTENINGCYCLE (SSC)

Most normal movements unconsciously begin a SSC

Eccentric muscle action that is immediately followed by concentric action in the direction of interest.

if there is minimal delay between the two muscle actions

There are four potential sources of the greater muscleforce in the concentric phase of an SSC:

Contractile potentiation

Reflex potentiation,

Storage and reutilization of elastic energy,

The time available for force development