Types of forces

Question 1

isotonic force

Answer 1

Change in the length of a muscle performed against a CONSTANT load
E.g. Performing a triceps extension / shoulder press

Question 2

Isokinetic force

Answer 2

Change in the length of a muscle, however is performed against VARYING load
This requires specialized equipment to ensure the speed of muscular contraction remains constant

Question 3

Isometric force

Answer 3

If the muscle length does not change, then an isometric contraction or force is being applied. E.g. pushing against an immoveable object, gripping a racquet or bat.

Question 4

Sub maximal force

Answer 4

Less than maximal force, generally used when accuracy is of most importance
E.g. putting in golf, throwing a dart, defending in cricket

Question 5

Maximal force

Answer 5

Result of perfect force summation, maximal muscle contraction and excellent technique achieve maximal force. E.g. kicking for distance, golf drive, baseball pitch

Question 6

Summation of force

Answer 6

Process that determines how to best use body segments depending on the demands of the task – power or accuracy?
POWER – more segments used. Forces usually sequentially summated – (softball hit, golf drive)
ACCURACY – less segments needed and usually summated simultaneously, timing – (netball goal shot)

Question 7

Force summation occurs in 2 ways:

Answer 7

1. Simultaneously-
   Where all body parts move at the same time to produce a force. Generally used to produce accuracy, however some activities do require this method to attain maximum power E.g. A snatch in weightlifting and a putt in golf.
2. sequentialy
   Where body parts are moved in sequence to produce a force.
   Generally used to produce maximal force in whole body actions such as throwing, kicking and striking
   E.g. A baseball pitcher, striking in golf, kicking in rugby

Question 8

How does one generate the most force

Answer 8

1. The stronger and larger muscles of the thighs and trunk are moved first followed by the smaller and faster muscles
2. Sequentially accelerate each body part so that optimum momentum passes from one body part to the next.
3. Each body part should be stable so that the next body part accelerates around a stable base to transfer momentum
4. Use as many body parts as possible, so force can be applied over the maximum possible time
5. Follow through is important to prevent deceleration of last segment and safe dissipation of force.