Fuel, Fire, and Force

Levers

Movement is made possible by lever systems that are formed from our muscles and joints working together. A lever system is made up of three parts: an effort, a load, and a fulcrum.

Effort in Levers

The effort is provided by the muscle in human body

Load in Levers

The load is the weight of the body and any additional resistance

Fulcrum

The fulcrum is the joint itself

External levers

These are the tools or equipment you use to extend your natural levers. You can choose different lengths to gain an advantage. For example using a racket, bat. etc.

First class lever + Example

A first class lever is when the fulcrum lies between the effort and the load. For example, the extension at the elbow of the downward phase of a bicep curl.

Second class lever + Example

A second class lever is when the load lies between the effort and the fulcrum. For example, any sporting action involving plantar flexion at the ankle.

Third class lever + Example

A third class lever is when the effort lies between the load and the fulcrum. It is the most common lever system in action

All or none principal

The 'all-or-none' principle states that when a motor neuron sends an action potential, all the muscle fibers in that motor unit will either fully contract or not contract at all. 

Mechanical Advantage Formula

Effort Arm / Load Arm

Mechanical Advantage of a First Class Lever

The mechanical advantage can either be =, >, < than 1. When the mechanical advantage is higher than 1, the lever favours force. when the mechanical advantage is lower than 1, the lever favours speed

Mechanical Advantage of a Second Class Lever

MA > 1, always favours force

Mechanical Advantage of a Third Class Lever

MA < 1, always favours speed

What is linear motion in kinematics?

Linear motion refers to movement in a straight line, such as an ice hockey puck sliding over ice.

What is curvilinear motion in kinematics?

Curvilinear motion is movement along a curve, such as a shot-put traveling through the air.

What is angular motion in kinematics?

Angular motion, or rotational motion, is movement around an axis, such as a gymnast rotating around a high bar.

What is general motion in kinematics?

General motion involves a combination of linear and angular motion.

What is Kinematics?

Kinematics is the study of motion

What is resultant motion?

Resultant Motion is the OVERALL movement of an object. This movement happens because of the COMBINATION of all forces acting on the object. It represents the ACTUAL path the object takes after all pushes, pulls, and influences are considered.

Newtons First Law of Intertia

An object will remain at rest or continue with constant velocity unless acted upon by an unbalanced force. Object resists changes to their state of motion so a heavier mass object = more inertia.

Newtons Second Law of Acceleration

Force = Mass x Acceleration, The acceleration of an object is proportional to the force acting on it and inversely proportional to its mass . More force results in more acceleration and more mass results in less acceleration if the same force is applied.

Newtons Third Law of Reaction

For every action, there is an equal and opposite reaction. When one body or object applies a force to another, the second body or object will apply a force equal in size but opposite in direction to the first body or object.

Center of Mass

Point at which mass and weight of an object are balanced in all directions.

Base of Support

Location on a body where most of the weight is supported. Wider the base of support, the greater stability.

Line of Gravity

Line of gravity is an imaginary vertical line passing through the centre of mass to pass down to a point in the base of support.

Summing Joint Forces

Different joints work together in a coordinated manner to produce a stronger, more powerful movement.

Impulse

To accelerate or decelerate an object, a force needs to be applied. Impulse = Force x Time elapsed

Momentum

Mass x Velocity, the quantity of motion of a moving body or mass in motion

Impulse-Momentum Relationship

The greater the impulse = greater change in momentum. A small force over long time or a large force over short time can both influence momentum

Angular Momentum

Moment of Inertia x Angular Velocity

Angular Velocity

Rotational speed with direction

Moment of Inertia

Moment of inertia is a measure of how difficult it is to spin something around. It is affected by the mass of the object and how far that weight is from the center.

What are macronutrients?

Macronutrients are nutrients needed in large amounts that provide energy. These include carbohydrates, fats, proteins, and water.

What role does carbohydrates play as a macronutrient?

Carbohydrates serve as a primary energy source for the body, providing fuel for physical activity and essential processes.

What role do fats play as a macronutrient?

Fats are a concentrated source of energy and are essential for absorbing certain vitamins and hormones, as well as providing insulation and protection.

What role does protein play as a macronutrient?

Proteins are vital for growth, repair, and maintenance of body tissues, as well as supporting immune function and producing enzymes and hormones.

What role does water play among macronutrients?

Water is crucial for hydration, regulating body temperature, transporting nutrients, and facilitating biochemical reactions in the body.

Glucose

We eat carbohydrates, they become glucose. Glucose is stored in the muscle and liver as glycogen.

What is the role of insulin in blood sugar regulation?

Insulin stores glucose as glycogen when blood sugar rises after eating, helping to maintain homeostasis.

What is the role of glucagon in blood sugar regulation?

Glucagon mobilizes stored glycogen into glucose, which raises blood sugar levels for energy during exercise.

How do insulin and glucagon work together?

Insulin and glucagon work together to maintain homeostasis in blood sugar levels: insulin lowers blood sugar by storing glucose, while glucagon raises it by releasing stored glycogen.

What is anaerobic glycolysis?

Anaerobic glycolysis is the process where glucose is broken down into pyruvate, which is then converted to lactate. This occurs very quickly, providing energy for high-intensity bursts of activity (e.g., a 400m sprint).

What is aerobic glycolysis?

Aerobic glycolysis is the process where pyruvate enters the mitochondria and undergoes the Krebs Cycle and Electron Transport Chain. This process is slower than anaerobic glycolysis but produces much more ATP (energy) for endurance events.

What is beta-oxidation?

Beta-oxidation is the process where fatty acids are broken down in the mitochondria to create Acetyl CoA.

What happens to Acetyl CoA in lipid metabolism?

Acetyl CoA enters the Krebs Cycle, leading to the Electron Transport Chain (ETC) to produce massive amounts of ATP.

What is the primary role of proteins during physical activity?

During physical activity, amino acids can be oxidized for energy, but their primary role is in muscle repair and hypertrophy (growth).

How do progesterone and estrogen collectively influence energy metabolism?

Both progesterone and estrogen together influence energy metabolism by contributing to increased fat utilization and glycogen sparing. This combined effect is more pronounced during the luteal phase of the menstrual cycle.

What is the significance of the combined effect of estrogen and progesterone on glycogen sparing?

Though estrogen has a glycogen sparing effect anytime it's high, the combined effect of estrogen and progesterone makes this effect more pronounced during the luteal phase.

What is Gastrointestinal Discomfort

A common cause of underperformance, especially for endurance athletes, are symptoms of nausea, vomiting and diarrhoea, categorised as Gastrointestinal Discomfort.

Prevention of GI

An athlete should practice their pre-race food routine, including: volume of food, their timing of food, and the digestibility of different foods before race day.

What is Low Energy Availability (LEA)?

Energy Availability is what is left for your body to function after you subtract the cost of exercise. Energy Intake (Food) - Energy Expenditure (Exercise) = Energy Availability. If result is too low, can lead to lack of bone building, hormone production, etc.

What is RED-S?

Relative Energy Deficiency in Sport (RED-S) is the clinical condition caused by long-term LEA. Some symptoms are irregular menstrual cycle, compromised bone health, low testosterone levels, decreased performance, and increased injury risk.

What are the three energy systems?

The body's energy systems: the Phosphagen system, Glycolytic (anaerobic & aerobic), and Oxidative system all work together to produce ATP (the energy currency used for all physical activity).

Phosphagen Energy System

• Fuel: PCr (Phosphocreatine)

• Duration and ATP Yield: 20 seconds; 1PCr = 1 ATP

• Recovery Capability: Coupled reaction recovery time required: 2-3 minutes

• Benefits: No fatiguing by-products

• Limitations: Short-lived, only lasts up to 20 seconds; limited supply

Glycolytic Energy System

• Fuel: Glucose

• Duration and ATP Yield: 1 Glucose molecule = 2 ATP; Dominant from 20 seconds to 2 minutes duration

• Recovery Capability: 20-60 minutes

• Benefits: Supports high-intensity efforts

• Limitations: Lactate fatiguing by-product; accumulation of H+

Oxidative Energy System

• Fuel: Glucose or Fat

• Duration and ATP Yield: Predominantly glucose = 38 ATP; Fat = 100-150 ATP per triglyceride molecule

• Recovery Capability: High capacity for recovery

• Benefits: Long-lasting; high ATP yield; minimal fatiguing by-products

• Limitations: Slow to activate; requires O2

V02 Max

VO2max is a measure of the maximum volume of oxygen that an individual can take in and use.

Running Economy

Running economy refers to the amount of oxygen a person uses at a given submaximal speed. It’s essentially the oxygen cost of the running movement.