Functional Movement Anatomy and Physiology

 

Body composition comprises two components:

• Body fat - Essential and excess body fat. Fat levels vary for different people influenced by factors such as age, genes, hormones, and gender. However, diet and lifestyle are the predominant factors affecting body composition in both men and women. 

• Non-fat (lean) mass - Bones, muscles, organs, tissue, and also water. Non-fat tissues are metabolically active meaning they burn kilojoules (also known as calories) whereas fat does not. 

Body fat is found all over the body including in muscle tissue, under the skin, and around organs. A certain amount of fat is required by the body to protect organs, provide fuel for energy and help with hormone regulation. However, this level of essential fat is quite small as seen in the below percentage amounts, any additional fat is known as excess fat:

• 2 - 5% in men.

• 10 - 13% in women. Women have more fat due to the hormone oestrogen which reduces the ability to burn energy after eating. Increased body fat benefits women during child-bearing age as more body fat is required during pregnancy.

There are various tools and calculation methods used to determine if body composition is within normal ranges of fat storage two common examples are:

• Body Mass Index (BMI) calculation - The Heart Foundation has developed a BMI calculator.  This process takes a person's weight in kilograms and divides it by the square of their height in meters to reach a result which then falls within underweight, normal, overweight or obese categories. It is a simple calculation, however, it does not differentiate between fat and non-fat components of body composition and therefore the results can be misleading, especially in individuals with high muscle tone.

• Body Fat Percentage calculation - This process considers a variety of measurements as well as gender, height, and weight to formulate a percentage of body fat which falls within Athlete, Fit, Acceptable or Obese categories. There are several types of calculators available for this task and depending on which one is used the results can vary dramatically. For example, the US Navy calculator takes into consideration hips, waist, and neck measurements whereas the calculation that is based on a book by Covert Bailey takes into consideration hips, waist, wrist, and forearm measurements. The ALeanLife website provides a calculator which incorporates all the various calculation methods.

The recommended methods of reducing excess body fat levels and therefore improving body composition are to eat reasonably portioned nutritionally balanced foods and undertake regular fitness activities. 

 

Muscular strength and endurance are often used for different types of physical activity and are developed in different ways.

• Strength is required to perform moderate to rapid bursts of movement. For example, running races 400m-800m in length (moderate strength and speed required) and 100m sprints (rapid strength and speed required).

• Endurance is required for much longer activities such as running in a marathon.

Strength, in this context, is often referred to power because the weight being moved (the body in a running race) is accelerating very rapidly. Other references to power include in weight lifting where the resistance (a barbell) is raised in a quick motion. However, it is worth noting that strength and power are separate terms and not always interchangeable. 

The development of strength and endurance requires exercising specific types of motor units (a combination of motor neurons and skeletal muscle fibres) in different ways.

• Type 1 (slow-twitch) motor units which are used for endurance activities due to their fatigue resistance are best developed through continuous aerobic exercise.

• Type 2A (intermediate fast-twitch) motor units which are used for medium length activities requiring moderate power and speed are best developed through resistance exercise.

• Type 2B (fast-twitch) motor units which are used for extremely rapid activities requiring maximum power and speed are best developed through plyometric exercises. 

 

There are nine major joint complexes within the body, each with its own normal range of motion, measured in degrees.

Various pieces of equipment can be used to help measure and record the range of motion of different joints:

• Goniometer - A protractor like device with a stationary arm, fulcrum (rotational joining piece), and a movement arm.

• Flexometer - 360° dial and weighted gravity needle with a strap which attaches to the limb.

• Inclinometer or Plurimeter - Dial based protractor which can be digital, used for measuring the range of motion (or incline) of a joint. Often used for measuring spinal movement.

• Plumb line - A vertical line that extends through key points in the human body and is used to determine if the client has correct postural alignment.

• Grid - A grid lined chart that is placed on the wall alongside an individual who is either sitting or standing and can be used to determine if postural alignment is correct. 

• Pressure biofeedback unit - A pressurised device used to measure the muscles of the lower back and abdomen and determine if they are providing stability for the spine.

• Tape measure - Simple measuring device that can be used to measure range of motion, especially for the spine.

• Camera - Helpful for recording before, during, and after images that hopefully show improvement.

• Video camera - Helpful for recording joint range of motion, especially in instances of limited movement and showing the client what needs to improve.

A Goniometer is the most commonly used measuring device. The process of using a goniometer is as follows:

• Align the fulcrum of the device with the joint to be measured.

• Align the stationary arm of the device with the limb being measured.

• Hold the arms of the goniometer in place while the joint is moved through its range of motion.

• The degree between the endpoints represents the entire range of motion.

The main joint complexes and their approximate normal ranges of motion are:

Joint Complex	Functional Movement	Description of Movement	Degrees
Ankles	Plantar flexion	Stand on the tip of your toes or pointing of toes.	50°
	Dorsiflexion	Backward bending of the foot at the ankle.	20°
Knees	Flexion	Touch calf to hamstring.	130°
	Extension	Straighten out knee as much as possible.	120°
	Internal rotation	Twist lower leg toward the midline.	10°
Hips	Flexion	Extend knee and bring thigh close to abdomen.	110°
	Extension	Move thigh backwards without moving the pelvis.	20°
	Abduction	Swing thigh away from midline.	45°
	Adduction	Bring thigh toward and across midline.	45°
	Internal rotation	Flex knee and swing lower leg away from midline.	45°
	External rotation	Flex knee and swing lower leg toward midline.	45°
Lumbar Spine	Flexion	Bend forward at the waist.	75°
	Extension	Bend backwards.	30°
	Lateral bending	Bend to the side	35°
Thoracic Spine	Flexion	-	20° - 45°
	Extension	-	25° - 45°
	Lateral flexion	-	20° - 40°
Cervical Spine	Flexion	Touch sternum with chin.	70 - 90°
	Extension	Point up with chin.	55°
	Lateral bending	Bring ear close to shoulder.	35°
	Rotation	Turn head to the left then right.	70°
Shoulders	Abduction	Bring the arm up sideways.	90°
	Adduction	Bring arm toward the midline of the body.	90°
	Horizontal extension	Swing arm horizontally backwards.	45°
	Horizontal flexion	Swing arm horizontally forward.	130°
	Vertical (hyper) extension	Raise arm straight backwards.	50°
	Vertical (forward) flexion	Raise arm straight forward.	170°
Elbows	Flexion	Moving forearm toward the body.	160°
	Extension	Bringing the forearm back to anatomical position (straight down).	145°
	Pronation	Twisting the forearm away from the body.	90°
	Supination	Twisting the forearm towards the body.	90°
Wrists	Flexion	Bending the hand down at the wrist	60°
	Extension	Raising the back of the hand towards the forearm.	60°
	Pronation	Rotating the forearm into a palm down position.	90°
	Supination	Rotating the forearm into a palm-up position.	90°
	Adduction (Radial flexion)	Bending hand to the left.	22°
	Abduction (Ulnar flexion)	Bending hand to the right.	22°

Injuries that are associated with joint movement include:

• Strains - When muscles and/or tendons are overextended.

• Sprains - Injuries to the ligaments which hold joints together.

• Fractures - Breaks, chips, or cracks in the bones usually as a result of trauma (impacting objects) or falling.

• Dislocations - Separation of the bones within a joint, common in high mobility joints such as the knee and shoulder.

Joints are controlled by two opposing sets of muscles, known as:

• Extensors - Responsible for opening (extending) the joint. For example, the tricep.

• Flexors - Responsible for bending (flexing) the joint. For example, the bicep.

Together they contract and relax in synchrony to enable joint movement. The joint and its movement is further supported by tendons (which attach muscle to bone) and ligaments (which link bone to bone).

Each of the joint complexes should be able to move freely through its specific range of motion (measured in degrees). Muscle imbalance and/or misaligned joints may mean that the normal range of motion is not able to be undertaken by the client. This is known as a limited range of motion and essentially means that the client is not very flexible. 

Increasing flexibility helps to prevent and relieve pain, correct posture, and reduce musculoskeletal injury. Flexibility is tested with stretching exercises, such as reach tests that target the lower back and hamstring muscles, supine hamstring test, hip flexor/Thomas test and shoulder flexion test.

There are three classifications of range of motion exercises designed to improve movement in specific joints:

• Passive Range of Motion (PROM) - The joint is moved through the entire range of motion by external manipulation by a third party. For example, the fitness professional guides the client's knee through its range of movement. Outside of situations such as recent or chronic injury, recent surgery, or immobilization this situation would be rare.

• Active Assisted Range of Motion (AAROM) - The client is able to use their muscles to move the joint through the range of motion but requires some level of support either from the fitness professional or a supportive aid/device such as a strap.

• Active Range of Motion (AROM) - The client is able to move the joint independently through its range of motion.

 

Having well developed cardiorespiratory endurance enables large muscle exercise that is dynamic and prolonged at moderate to high levels of intensity. The term 'physically fit' is often used to refer to someone who has highly developed cardiorespiratory endurance. 

There are three types of energy pathways that help fuel the muscles to perform functional movement:

• Alactic Anaerobic Energy System (ATP-PCr) - The main source of muscle energy for high-intensity exercises over a very short time period (between 5-15 seconds) such as a short sprint or the lifting of weights.

• Lactic Anaerobic Energy System (also known as the Glycolytic System) - The main source of energy for high-intensity exercises that are undertaken over slightly longer periods (1-2 minutes) such as a 400m race.

• Aerobic Energy System (also known as the Oxidative system) - The endurance energy system, works by using food energy and oxygen to support activity over much longer periods (ie. an hour or more) such as running a marathon or long bike ride. When operating under the aerobic energy system the body converts oxygen, carbohydrates (glucose), fats and even proteins into usable Adenosine Triphosphate (ATP) using a combination of the Krebs Cycle (or the Citric Acid Cycle) and the Electron Transport Chain. This process is fairly complicated, however, the main takeaway is that whilst it is slower at producing energy than the first two systems it is more sustainable as it utilises vast reserves of oxygen, carbohydrates, fats and proteins to continually produce ATP and can thus be used over longer periods.

The following video further explains the three energy systems:

In regards to building cardiorespiratory endurance, it is the aerobic energy system which must be utilised. Cardiorespiratory endurance is developed by undertaking continuous aerobic exercise whilst also increasing the length and difficulty of physical activity, in particular cardio exercises.

High-intensity interval training (HIIT) is a good method of building physical fitness. This method of exercise works the body in multiple bursts of high-intensity activity for short periods of time, just enough to surpass the anaerobic threshold (approximately 15 seconds) before returning to a more steady aerobic pace. 

Determining an individual's cardiorespiratory endurance ability is done through two different measuring processes:

 

The human body controls balance through a process that includes position detection, feedback, and adjustment. This process uses a combination of three sensory components all communicating with the brain:

• Vision - The eyes provide visual feedback to the brain regarding orientation, depth perception, and spatial location relative to objects.
• Vestibular function - Located within the inner ear this system can detect a variety of head movements such as nodding or rotation. It helps to prevent the feeling of dizziness or vertigo that is associated with movement.
• Proprioception - The perception of movement and spatial orientation from external stimuli via the skin, joints, and muscles.

Centre of gravity is a term used to describe a hypothetical point in the body around which all the parts balance. A person's centre of gravity constantly changes because the human body moves into many different positions on a regular basis, it can even exist outside of the body. 

In the anatomical position (standing upright with arms by our sides and palms facing forward) the centre of gravity is approximately anterior (infront of) the second sacral vertebra.

Because humans stand and move in an upright posture our centre of gravity is quite a distance away from our base of support. The base of support consists of an individual's wide stance and foot size and it helps to maintain balance and prevent falling. The larger the base of support, such as legs in an outward stance, the greater the protection from toppling. The muscles surrounding the body's core section also help to maintain balance.

The closer an individual's centre of gravity is to the base of support, the more stable the individual is. Therefore, adjusting one's position can improve balance. For example, a tightrope walker is trained to hold the pole low while the pole is weighted at both ends and a surfer maintains balance on the surfboard by positioning themselves with flexed knees, a forward crouch, and hands held low.

The human body is capable of a certain amount of movement/changes to the position of the centre of gravity without undue effect, this is known as postural sway. However, it is only possible to deviate so far outside of the centre of gravity before a loss of stability (falling) will occur. This is known as the limits of stability.

To prevent falling, an individual must adjust their base of support to re-establish balance. Detecting when this adjustment is required is controlled by the vestibular system which is located within the inner ear. Communication of messages to initiate necessary corrective movements are then sent via the central nervous system.

The actions that the human body undertakes to vary its stance and re-establish balance when the limits of stability have been reached are known as balance strategies and humans have three of them:

• Ankle strategy - Small movements in the ankle, foot, and toes that help to maintain balance during standing.

• Hip strategy - Movements such as swaying and moving the trunk to redistribute weight within the centre of gravity.

• Step strategy - Taking a step to widen the base of support. 

We also have some postural reactions, which are either present from birth or develop during infancy or early childhood. These reactions help to re-establish balance and protect certain body parts in the event of falling:

• Righting reactions - Keep the head in a normal position, return the body to a normal position, and adjust body parts in relation to the head. These reactions a more dominant when the surface is stable but the body is shifted ie. if someone is pushed from behind and they fall forwards.

• Equilibrium reactions - Rotation of the head and trunk away from the direction of displacement, with some extension of extremities (limbs) to further restore balance. These reactions are more dominant when the surface is unstable ie. on water or other moving objects such as a horse or train. 

• Protective reactions - Reactions of the arms and legs to extend forward, sideward, or backward to either break the fall or otherwise restore balance.

Everyone is prone to balance disruption from time to time, however, certain factors can exascerbate the situation and increase the risk of falling and injury.

 

It is a skill that is utilised frequently in fitness environments, particularly in high-paced sporting events such as soccer or basketball.

Functional movement is controlled by the nervous system and involves muscles moving joints in a variety of directions. The sensory receptors responsible for communicating the 'messages' to and from the central nervous system and the muscles can be trained to react faster and thus move the body more swiftly. This is the process of improving agility and reaction time. In addition to improved agility and sports performance, there are also cognitive benefits to this type of exercise.

The best way to develop agility and reaction time is to perform repetitive action style exercises such as drills involving rope ladders (laid out on a flat area) or cones that must be hurdled and weaved through rapidly.

 

Power consists of two components, strength and speed. Strength relates to basic muscular strength which has already been covered in this topic, however, when discussed in relation to power it requires speed to be an effective component.

This coupling is evident when a sprinter launches themselves from the starting line at the beginning of a race or when a baseballer pitches a high-velocity ball towards the batsman.

 

Coordination, as the name suggests, involves two or more body functions or movements operating in tandem (coordinating). This ability, often used in conjunction with other skill-related components of fitness such as balance and agility, can be developed through practice and repetition. 

Functional movement is controlled by the nervous system and involves muscles moving joints in a variety of directions. The actual movements are known collectively as Motor Skills and they are broadly categorised into two sections:

• Fine Motor Skills - Requires precise control of the small muscles in the hands, wrists, fingers, and feet. For example, ball handling in soccer utilises fine motor skills of the feet, whereas coordination in tennis requires hand-gripping and feet coordination skills.

• Gross Motor Skills - Movements that involve large muscle coordination such as running, jumping, and sliding. These movements can be reinforced through fitness training.

Both types of motor skills require high levels of coordination. For example, gross motor skill coordination may include running and jumping over hurdles. Fine motor skills coordination includes hand-eye coordination. This ability requires the simultaneous use of both the hands and the eyes. The eyes perceive information and send the message to the brain which then guides the hands to carry out a specific fine motor skills movement. 

 

As mentioned above in the balance section, proprioception is the perception of movement and spatial orientation from external stimuli via the skin, joints, and muscles. Essentially it is the ability of the body to determine if it is moving and where different parts of the body are positioned even if they are not visible.  

Proprioception works together with other sensory components of the body including the eyes and the inner ear, however, in the absence of one or more of these components the body becomes more reliant on proprioception. For example, during a game of pin the tail on the donkey the participant is blindfolded (removing the sensory ability of sight) and they are spun in circles which creates a feeling of dizziness (reducing the sensory ability of the inner ear) and they are then required to maneuver the arm and hand to try and attach the 'tail' onto the picture of the donkey.

Proprioception helps with this task by telling the brain that the arm/hand is raised at approximately shoulder height and outstretched. The body is 'searching' for the picture of the donkey which is attached to the wall. When the sensors in the skin feel the wall the brain is able to orientate itself somewhat and complete the task of pinning the tail on the donkey.

Proprioception also helps to communicate valuable messages relating to ground surface stability through the sensors in the feet. Uneven surfaces will trigger the use of strategies to help maintain balance such as the ankle or the stepping strategy.