Muscle Contraction: All Or Nothing

The All or None Law is a physiological principle which relates to the response to stimulus in excitable tissues. It was first established for contraction of heart muscle by Henry P Bowditch in 1871. It was later found that the all or none law was also applicable to skeletal muscle contraction.

“An induction shock produces a contraction or fails to do so according to its strength; if it does so at all, it produces the greatest contraction that can be produced by any strength of stimulus in the condition of the muscle at the time.” – Henry Bowditch

In other words, an action potential (stimulus) will either cause complete activation of the muscle fibre or none at all. The action potential must meet or pass a certain threshold (usually between 55mV-65mV) in order for a contractile response to occur. The variants in contractile muscle strength come from the number of fibres recruited and the increase in individual muscle fibre size and strength due to an increase in the number and size of myofibrils.

About the Author

Job Role Sports Nutritionist and Social Media Coordinator Qualifications Bsc Sport and Exercise Science Steph has a competitive athletic background which spans 19 years. As a child she performed with the English Youth Ballet and had performed on the West End stage by the age of 10. Her enthusiasm for sport and fitness continued to grow as she did, encouraging her to learn more about nutrition and training. She began using her knowledge and personal experience to help others when she began coaching at the age of 16. From here, she went on to study Sport and Exercise Science at the University of Essex during which time she also received the Most Promising Newcomer Award from her University to mark her outstanding contribution to sport. During her first year of study she was introduced to partner stunt acrobatics and artistic gymnastics. After one year of dedicating herself to a lifestyle revolving around her sport, she was training with the best team in the UK who are currently ranked fifth in the world. Steph has worked in both the private and public sector coaching children and adults from grassroot to elite level as well as providing them with cutting edge advice on how to reach their goals. Steph has received awards for her choreography and has competed nationally and internationally meaning that she can back up her scientific knowledge with a wealth of experience. As our resident Sports Nutritionist, Steph is here to provide the most current and evidence based fitness, health and nutrition information to help you reach your health and fitness goals.

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