Component 1 1 1 a Skeletal and muscular

Component 1 ‒ 1. 1. a. Skeletal and muscular systems © OCR 2019

Learning outcomes • By the end of this topic you should be able to demonstrate knowledge and understanding of: • • • role of muscles in creating movement types of movement and antagonistic pairs at hinge joints types of movement and antagonistic pairs at ball and socket joints types of movements and muscles of the wrist planes of movement analysing movement with reference to: • • joint type and movement produced gonist and Antagonist muscles involved Types of muscle contraction taking place structure and role of motor units in skeletal muscle contraction nervous stimulation of the motor unit muscle fibre types recruitment of different types of fibres during exercise of differing intensities and during recovery © OCR 2019

Timings Topic Allocated time Types of movement and antagonistic pairs at hinge joints 1 hour Types of movement and antagonistic pairs at ball and socket joints 2 hours Know the types of movements and muscles of the wrist 1 hour Role of muscles in creating movement 2 hours Planes of movement 2 hours Structure and role of motor units in skeletal muscle contraction 2 hours Nervous stimulation of the motor unit 1 hour Muscle fibre types 2 hours Recruitment of different types of fibres during exercise of differing intensities and during recovery 2 hours Total 15 hours © OCR 2019

Types of synovial joint (hinge joint) Hinge joints You need to know the make up of the knee and elbow joints. © OCR 2019

Types of synovial joint (hinge joint) Hinge joints The muscles which create movement in the elbow joint. Biceps Brachii The muscle which contracts to cause flexion of the elbow joint Triceps Brachii The muscle which contracts to cause extension of the elbow joint © OCR 2019

Types of movement at hinge joints Movement at a hinge joint FLEXION – Decreasing the angle at a joint. (Bending the arm at the elbow joint) Flexion EXTENSION - Increasing the angle at a joint. (Straightening the arm at the elbow joint) Extension © OCR 2019

Types of synovial joint (hinge joint) Knee joint The muscles which create movement in the knee joint. The muscles which contract to cause flexion of the knee joint The muscles which contract to cause extension of the knee joint © OCR 2019

Types of movement at hinge joints Movement at a hinge joint FLEXION – Decreasing the angle at a joint. (Bending the leg at the knee joint) Flexion EXTENSION - Increasing the angle at a joint. (Straightening the leg at the knee joint) Extension TASK: Describe a specific sporting example of both Flexion and Extension at both the Knee and the Elbow. © OCR 2019

Ankle joint The ankle is a hinge joint. The articulating bones are the tibia, fibula and talus. © OCR 2019

Ankle joint Movements occurring at the ankle joint are dorsiflexion and plantarflexion. The muscle which contracts to cause dorsiflexion is the tibialis anterior Tibialis Anterior Gastrocnemius The muscles which contract to cause plantarflexion are the gastrocnemius and soleus © OCR 2019

Ankle joint – plantarflexion Plantar flexion is where an athlete or performer POINTS their toes. For example completing the upward phase of a calf raise. This is caused by contraction of the gastrocnemius and soleus and relaxation of the tibialis anterior. © OCR 2019

Ankle joint - dorsiflexion Dorsi flexion is where an athlete or performer pushes the toes up towards the knee. For example, to maintain stability in a squat the ankle joint will dorsiflex to keep the feet flat on the floor. This is caused by contraction of the tibialis anterior and relaxation of the gastrocnemius and soleus. © OCR 2019

Types of synovial joint (ball and socket) Ball and socket joints You need to know the make up of the shoulder and hip joints. Humeral Head Femoral Head (ball) Acetabulum Glenoid cavity (socket) © OCR 2019

The shoulder joint (ball and socket) Shoulder muscles You need to know the make up of the muscles responsible for movement at the shoulder. The deltoid is divided into 3 sections. • Anterior Deltoid • Medial Deltoid • Posterior Deltoid These muscles will contract to cause any movement involving raising of the arms from the anatomical position. © OCR 2019

The shoulder joint (ball and socket) Upper back muscles The Trapezius, Teres Minor and Latissimus Dorsi These muscles of the back oppose the movement of the deltoid causing movements which bring the arms down from above the head or the arms back from in front of the body. © OCR 2019

The shoulder joint (ball and socket) Chest muscles The Pectoralis Majoris These muscles of the chest also oppose the movement of the deltoid causing movements which bring the arms down from above the head or the arms forwards in front of the body. © OCR 2019

Types of movement at ball and socket joints Ball and socket joints Where the rounded end of one bone fits inside the cup-shaped end of another bone. Ball and socket joints allow movement in all directions. These are the most mobile joints in the body. Examples found in the body include the shoulder and hip joints. Why are these joints important for sport? Most sporting movements require the type of movement the shoulder and hip allow. i. e. tennis serve © OCR 2019

Types of movement at ball and socket joints - shoulder Flexion and extension FLEXION Bringing the arms up from the anatomical position forwards over the head as in a block in volleyball EXTENSION Moving the arms forwards and down from above the head. As in a volleyball spike. © OCR 2019

Types of movement at ball and socket joints - shoulder Medial and lateral rotation ROTATION Movement where the articulating bones turn around their longitudinal axis in a screwdriver action. MEDIAL ROTATION is where the movement is towards the midline of the body as in the forehand top spin follow through of a tennis player LATERAL ROTATION is where the movement is away from the midline of the body as in the backhand top spin follow through of a table tennis player © OCR 2019

Types of movement at ball and socket joints Adduction and abduction ADDUCTION Sideways moving limb towards midline of the body. REMEMBER: Adduction is to ADD towards the midline. ABDUCTION Sideways moving limb away from midline of the body REMEMBER: Abduction is to TAKE AWAY from the midline. © OCR 2019

Types of movement at ball and socket joints Movement at a ball and socket joint Rotation/Circumduction: The joint moves in a circular motion e. g. service action or bowling action. Let’s see if you fully understand… TASK 1: Draw and describe a simple diagram of the Knee Joint and label the bones that move around this (the Articulating Bones). TASK 2: Name a Physical Activity that involves both Flexion and Extension of the Knee Joint. TASK 3: Draw and describe a simple diagram of the Hip Joint and label the bones that move around this (the Articulating Bones). TASK 4: Describe a skill in a physical activity that involves both abduction and adduction of the hip joint. © OCR 2019

Types of movement at ball and socket joints Movement at a ball and socket joint Flexion and Extension: Increasing and decreasing the angle at the joint. Abduction and Adduction: determined from the ‘MIDLINE’ of the body. Abduction Adduction © OCR 2019

Types of movement at the shoulder joint Horizontal flexion and extension Horizontal flexion/extension: The arm or leg move parallel to the ground forward (horizontal flexion) or backwards (horizontal extension). For example: The boxer delivering a right hook will move the arm parallel to the ground forwards creating horizontal flexion. This would be caused by contraction of the pectoralis majoris and the anterior deltoid. The preparation phase of the right hook when the arm is drawn back would be horizontal extension. © OCR 2019

Wrist joint The wrist is a condyloid joint which is the second most moveable synovial joint Movement at the wrist includes flexion and extension. Flexion is where the hand is brought forwards and upwards from the anatomical position, and extension is where the hand is brought backwards and downwards. © OCR 2019

Muscles of the wrist joint The wrist flexors contract to cause flexion of the wrist joint. The wrist extensors contract to cause extension of the wrist joint. © OCR 2019

Planes and axes of motion The body is capable of movement in three planes of motion: * FRONTAL * TRANSVERSE * SAGITTAL. © OCR 2019

Planes and axes of motion The transverse plane is where any form of rotation occurs around the longitudinal axis. For example a spin in ice skating. It is also associated with horizontal flexion and extension. © OCR 2019

Planes and axes of motion Frontal plane The frontal plane divides the body into front and back halves. Movements are largely towards or away from the midline of the body. Abduction and Adduction of the shoulder and hip occur in the frontal plane. Examples of movements in this plane are cartwheel and star jumps. © OCR 2019

Planes and axes of motion Sagittal plane The sagittal plane divides the body into left and right halves down the midline of the body. It is largely associated with flexion and extension of the joints. Examples of movements in this plane are the knee joint when striking a football or a somersault in gymnastics. © OCR 2019

Functional roles of muscles and types of contraction Antagonistic pairs Skeletal muscles do not work in isolation at a joint to create movement. At each joint there will be two or more muscles which act in opposition to create movement. These muscles are known as the agonist and antagonist. © OCR 2019

Functional roles of muscles and types of contraction Antagonistic pairs AGONIST – the muscle responsible for creating movement at a joint. Also known as a prime mover e. g. the bicep brachii contracting in the upward phase of a bicep curl. ANTAGONIST – the muscle that opposes the agonist providing a resistance for coordinated movement. The tricep brachii relaxing in the upward phase of a biceps curl. FIXATOR – the muscle that contracts to stabilize an area of the body to enable efficient movement. © OCR 2019

Functional roles of muscles and types of contraction Muscle contractions Skeletal muscle fibres are only capable of contracting or relaxing. By contracting the muscle creates a force against the bones of the skeleton to create movement at a joint. There are two main types of contraction, ISOTONIC contractions are where the muscle contracts and changes length which will create movement at the joint. ISOMETRIC contractions are where the muscle contracts creating a force but no movement takes place. An example of an isometric muscle contraction is the deltoid in the crucifix on the rings in gymnastics. © OCR 2019

Functional roles of muscles and types of contraction Muscle contractions There are two types of ISOTONIC contractions: CONCENTRIC contraction where the muscle contracts and shortens reducing the angle between articulating bones at a joint. For example the biceps brachii in the upward phase of a bicep curl. ECCENTRIC contraction where the muscle contracts and lengthens producing tension. This helps to resist forces like gravity to control joint movement. The biceps brachii contracts eccentrically in the downward phase of the bicep curl to control the bar down to its original position. © OCR 2019

Movement analysis You will be required to consider a diagram, illustration or described situation and identity: • joint type • movement produced • agonist and antagonist muscles • types of muscular contraction. For example, the knee joint of the footballer’s right leg in the picture is a hinge joint, the movement at present is flexion the agonist muscle is the biceps femoris which is producing a concentric muscle contraction and the antagonist is the rectus femoris. © OCR 2019

Movement analysis tables Joint Elbow Knee Ankle Joint type Hinge Movement Agonist Antagonist Flexion Biceps Brachii Triceps Brachii Extension Triceps Brachii Biceps Brachii Flexion Biceps Femoris Rectus Femoris Semimembranosus Vastus Lateralis Semitendinosus Vastus Medialis Vastus Intermedius Extension Rectus Femoris Biceps Femoris Vastus Lateralis Semimembranosus Vastus Medialis Semitendinosus Vastus Intermedius Dorsiflexion Tibialis Anterior Gastrocnemius Soleus Plantarflexion Gastrocnemius Soleus Tibialis Anterior © OCR 2019

Movement analysis tables Joint Wrist Hip Joint type Condyloid Ball and Socket Movement Agonist Antagonist Flexion Wrist Flexor Wrist Extensor Extension Wrist Extensor Wrist Flexor Flexion Iliopsoas Gluteus Maximus Extension Gluteus Maximus Iliopsoas Abduction Gluteus Medius Gluteus Minimus Adductor Brevis Adductor Longus Adductor Magnus Adduction Adductor Brevis Adductor Longus Adductor Magnus Gluteus Medius Gluteus Minimus Medial Rotation Gluteus Medius Gluteus Minimus Gluteus Maximus Lateral Rotation Gluteus Maximus Gluteus Medius Gluteus Minimus © OCR 2019

Movement analysis tables Joint Shoulder Joint type Ball and Socket Movement Agonist Antagonist Flexion Anterior Deltoid Pectoralis Majoris Posterior Deltoid Latissimus Dorsi Extension Posterior Deltoid Latissimus Dorsi Anterior Deltoid Pectoralis Majoris Abduction Latissimus Dorsi Pectoralis Majoris Medial Deltoid Latissimus Dorsi Pectoralis Majoris Horizontal Flexion Pectoralis Majoris Posterior Deltoid Teres Minor Horizontal Extension Posterior Deltoid Teres Minor Pectoralis Majoris Medial Rotation Teres Major Subscapularis Teres Minor Infraspinatus Lateral Rotation Teres Minor Infraspinatus Teres Major Subscapularis Adduction © OCR 2019

The motor unit and skeletal muscle contraction A skeletal muscle can only contract when stimulated by an electrical impulse sent from the central nervous system. Motor Neurons are specialised cells which transmit nerve impulses to the skeletal muscle fibres causing them to contract and thus creating movement. The motor neuron and associated muscle fibres are known as a MOTOR UNIT. © OCR 2019

Action potential Sending the nerve impulse to the muscle fibres is an electrochemical process which relies on an ACTION POTENTIAL to conduct the nerve impulse down the axon to the motor end plate. The dendrites collect the signals and the axon transmits the signal to the neuromuscular junction. © OCR 2019

Neuromuscular junction The point where the axon’s motor end plate meets the muscle fibre is known as the NEUROMUSCULAR JUNCTION. The gap between the end plate and the muscle fibre is known as the SYNAPTIC CLEFT. Once an impulse reaches the end plate it stimulates the vesicle to release the neurotransmitter ACETYLCHOLINE (Ach) which is then secreted across the synaptic cleft. If Ach is secreted above a threshold then the action potential will be transmitted into a muscular contraction. © OCR 2019

All or none law If a motor unit receives a stimulus to create an action potential that has reached threshold all the muscle fibres within the motor unit will contract at the same time and with maximum force. If the action potential does not reach threshold, none of the fibres will contract. This is known as the ALL OR NONE LAW. © OCR 2019

Muscle fibre types Any one skeletal muscle can contain three different types of muscle fibre. Each fibre type has different characteristics which determine the duration and intensity of the exercise being undertaken and the type of contraction taking place. The muscle fibres are: Type 1 – Slow Oxidative Type 2 a – Fast Oxidative Glycolytic Type 2 b – Fast Glycolytic © OCR 2019

Slow oxidative muscle fibres are designed to store oxygen in MYOGLOBIN and process the oxygen in the MITOCHONDRIA to break down fats and glucose in to ATP the only useable form of energy in the human body. For this reason the slow oxidative fibres have a high density of mitochondria and myoglobin and a dense network of capillaries to transport the oxygen to the cells. © OCR 2019

Slow oxidative muscle fibres These fibres work aerobically, which means they can withstand fatigue for long periods, but can only produce a small amount of force in the contraction. Each individual has a different make up of muscle fibres within the muscle itself which will determine the type of activity they are successful at. For example the gastrocnemius of a long distance runner may have around 70% slow oxidative fibres optimizing performance in endurance events. © OCR 2019

Fast glycolytic muscle fibres are suited to those athletes involved in explosive, power events such as Shot Put and 100 m sprint. Unlike SO muscle fibres they can exert a large force and have a fast contraction and relaxation time. They have large stores of PHOSPHOCREATINE which enables an immediate energy supply. © OCR 2019

Fast glycolytic muscle fibres They work anaerobically and as such can only last a short duration before fatigue. They are the largest type of fibre and have large neurons with many fibres connected to one neuron which helps to exert a larger force of contraction. A shot putter would most likely have a very high percentage of type 2 b fibres in the deltoids, pectoralis majoris and quadriceps. © OCR 2019

Fast oxidative glycolytic muscle fibres Fast oxidative glycolytic muscle are structurally designed to produce a large amount of force relatively quickly but are also able to resist fatigue. Similar to Type 2 b muscle fibres they have large neurons which innervate many muscle fibres at once. They also have large stores of phosphocreatine which help to maintain a good anaerobic capacity. © OCR 2019

Fast oxidative glycolytic muscle fibres However, unlike slow oxidative fibres they have moderate mitochondrial and myoglobin density which results in only moderate fatigue resistance and aerobic capacity. © OCR 2019

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