Question

If you wanted a muscle to lift a very strong load, what muscle fiber arrangement would you want to use?

In what two ways does optimal length increase the force a muscle is able to generate?

Answer 1

If we want to lift a very strong load ,we would prefer Type 2B muscle fibres.It is also called as fast fibres and white fibres.Type 2B fibres do not have mitochondria ,hence they appear colourless,that is why the name is white fibres .These arrangement of fibres stores energy that can be used for short, extremely explosive and high intensity works.Type 2A fibres are used for strength activities which requires heavy amount of force in shot period of time.

Effect of optimal length on the force generation by muscle:

• ​​​​​ when the muscle is between 80% and 120% of its optimal resting length,there will be maximum generation force by a muscle.At this intermediate length,generally called optimal length there will be maximum overlapping of actin and myosin filaments.As a result of this overlapping, it creates maximum number of cross -bridges.hence the greater force is generated by the muscle.
• At this optimal length, the length of sarcomere will also be changed .This has a great effect on the attachment and detachment of cross -bridges.At longer length of sarcomere ,the head of the myosin barely fit between the thick and thin filaments.Then they bind rapidly to form cross -bridges.Therefore ,the force generated by the muscle will be maximum at this optimal length.