CSCS

Preparatory class - Future Self Performance Institute

Chapter 1 - Structure and Function of Body System
Introduction - Musculoskeletal system / Neuromuscular system / Cardiovascular
system and Respiratory system.

Morphology and Physiology of different types of muscle and involvement in

different sports events and all other systems.
Musculoskeletal System

.
Functions
Produce RBC (Red blood cells)

Protect internal organs

Stores mineral and release when it's

needed

Support the body

Facilitates movement
Skeletal system
Appendicular Skeleton
Shoulder girdle
Bones of arms/wrists/hands
Pelvic girdle
Bones of legs/Ankle/Feet
Axial Skeleton
Skull / Vertebral column /
Ribs and Sternum.
Bones
Vertebral column
 Muscle Fiber -
Epi/Peri/Endomysium
Skeletal Musculature
Motor Unit - Neuromuscular junction
A Motor neuron and the muscle fibers
it innervates are called a motor unit.

All the muscle fibers of a motor unit

contract together when they are
stimulated by the motor neuron.
Actin and Myosin
Functional unit of muscle - Sarcomere
Action Potential
https://www.youtube.com/watch?v=m9L7kODxCc4 - AP to Muscle contraction
https://www.youtube.com/watch?v=zbo0i1r1pXA - Motor unit and Action potential
https://www.youtube.com/watch?v=BVcgO4p88AA - Cross bridge cycle
https://www.youtube.com/watch?v=-IAoht28e7I - Size Principle

The discharge of an action potential from motor nerve signals the release of
calcium from the sarcoplasmic reticulum into the myofibril, causing tension
development in muscle.
Sliding Filament theory

Resting Phase -
Calcium stored in sarcoplasmic reticulum
Actin & Myosin uncoupled
Excitation - Contraction Coupling Phase
Nerve impulse generated
Ca++ released from vesicles
Ca++ binds with troponin & Turn actin
Actin & Myosin coupled
Contraction Phase
ATP used for power stroke
Myosin head pull the actin - need ATP
Myosin head detach from actin - need ATP
Recharge Phase
Both Ca++ & ATP needed to continue this process
Relaxation Phase
Nerve impulse stopped
Ca++ Back into Sarcoplasmic reticulum
Phases and Videos of
Sliding filament theory
https://www.youtube.com/watch?v=
nTZnBdeIb5c&t=57s - Sliding
Filament Theory
Contraction of myofibril
Neuromuscular System
Muscle fibers are innervated by motor neurons that transmit impulses in the form of electrochemical
signals from the spinal cord to muscle.
Activation of muscles
All or none principle
Twitch
Tetanus
Muscle Fiber types
Type I & II
Motor Unit Recruitment patterns
Proprioception
Muscle Spindles
Golgi Tendon Organs
Twitch, Twitch summation, and tetanus
A whole muscle's response to different rates of stimulation

(a) twitch contraction, a single stimulus is delivered, and the muscle contracts and relaxes. This is
not the normal way of muscles operation. It is a result of certain nervous system problem.

(b) Summing of contraction, stimuli are delivered more frequently, so the muscle does not have
time to completely relax; contraction force increases because the effects of the individual twitches
are summed. This is the most type muscles activity.

(c) Unfused tetanus, more complete fusion of the twitches occurs as stimuli are delivered at a still
faster rate.

(d) Fused tetanus, a smooth continuous contraction without any evidence of relaxation, results
from a very rapid rate of stimulation.
.
Muscle fiber types - Type I - Type IIa - Type IIx
Motor Unit Recruitment patterns
Motor unit recruitment is the process by which different motor units are activated
to produce a given level and type of muscle contraction.
Muscular force graded in two ways - Variation in frequency (Intensity) / number of
motor unit activated (Recruitment).
Eg. Distance running - slow twitch motor units/Sprint - fast twitch motor units, activity
like near maximum exercise like power clean - fast twitch fiber make more significant
contribution.
The force output of a muscle can be varied through change in the frequency of
activation of individual motor units or change in the number of activated motor units.
Cardiovascular system - Heart chamber / Valves
Conduction system
Heart rate
The resting heart rate normally
ranges from 60 to 100 beats/min
fewer than 60 beats/min is called
bradycardia and more than 100
beats/min is called tachycardia.
Electrocardiogram
Blood vessels
.
.
Respiratory system
 Exchange
. of
respiratory
gases
.

Pleural pressure and Alveolar pressure

Chapter 2 - Biomechanics of resistance exercise
Biomechanics focuses on the mechanisms through which the musculoskeletal
components interact to create movements.

It’s important to design safe and effective resistance training programs.

Primary movements in sports activities / exercise / biomechanical principles

related to human strength and power.

Discuss about the primary source of resistance to muscle contraction used in

exercise devices - Including gravity / Inertia / Friction / Fluid resistance, and elasticity.

Joint biomechanics in resistance training.

Skeletal Musculature
.
A Lever

FR - Force resistance (Load)/ FA - Force applied (Effort) / MRF - Moment arm

of resistance force / MAF - Moment arm of applied force
 Muscle force / Resistive force
MF - Force generated by biochemical activity or the
stretching of noncontractile tissue, that tends to draw
the opposite ends of a muscle toward each other.

RF - Force generated by a source external to the

body that acts contrary to muscle force.
(Gravity/inertia/Friction)
Levers of the Musculoskeletal system
Mechanical Advantage:

If the effort arm is longer than the resistance arm, less force
is required to move the resistance.

Class II levers are advantageous for applying large amounts

of force but they are not good for accelerating objects
quickly. They amplify force in the movement.
Mechanical Disadvantage:

If the effort arm is shorter than the resistance arm; more

force is required to overcome the resistance.

Class III levers are not advantageous for applying large

amounts of force but they are good for accelerating objects
quickly. They amplify the speed of the movement.
Mechanical advantage of Patella
.
Moment arm & Mechanical advantage
.
When MA is
shorter from axis
there is less
mechanical
advantage
Skeletal muscles and Mechanical advantage
● Most of the skeletal muscle operate in
mechanical disadvantage.
● Hence during sports and other
physical activities, forces in the muscle
& tendons are much higher than those
exerted by the hands or feet on
external objects or the ground.
● As a weight is lifted, the moment arm
through which the weight acts, and
thus the resistive torque, change with
the horizontal distance from the weight
to the elbow.
Variation in tendon insertion
Tendons are fibrous connective tissues that connect muscles to bones and play a critical role in transmitting forces generated by
muscle contraction to produce movement. The location and size of the tendon's insertion into bone can vary among individuals, which
can have advantages and disadvantages in sports.
Advantages:
1. Increased strength: Tendons with larger insertion areas can generate greater forces, leading to increased strength and power in
certain movements. For example, a larger Achilles tendon insertion area has been linked to better performance in jumping and
sprinting.
2. Improved efficiency: The location of the tendon's insertion into the bone can also affect the lever arm of the muscle-tendon unit,
leading to more efficient force transmission and improved performance. For example, a more distal insertion of the patellar tendon
has been associated with improved jumping ability.
3. Decreased injury risk: A larger tendon insertion area can distribute forces more evenly, potentially reducing the risk of injury.
Additionally, a more proximal insertion can provide greater stability and reduce the risk of joint instability and injury.
Disadvantages:
1. Reduced range of motion: A larger tendon insertion area may limit the range of motion, potentially impairing performance in
sports that require greater flexibility.
2. Increased injury risk: While a larger tendon insertion area can distribute forces more evenly, it can also increase the risk of injury if
the forces exceed the tendon's capacity. Additionally, a more distal insertion can increase the risk of certain injuries, such as
patellar tendinopathy.
3. Less adaptability: Tendons with smaller insertion areas may be more adaptable to training and changes in physical demands, while
tendons with larger insertion areas may be less adaptable.
Tendon Insertion
● Tendon insertion away from the joint angle: When the tendon inserts further
away from the joint, it can provide greater leverage, resulting in greater force
production. Sports that require explosive movements, such as jumping and
sprinting, can benefit from this type of tendon insertion. For example, a more
distal insertion of the patellar tendon is associated with better jumping ability.
● Tendon insertion close to the joint angle: When the tendon inserts closer to
the joint, it can improve the joint's stability and control. Sports that require
greater stability, precision, and control, such as gymnastics, diving, and figure
skating, can benefit from this type of tendon insertion. For example, a more
proximal insertion of the Achilles tendon is associated with better balance
and control during jumping and landing tasks.
● It's important to note that an athlete's individual biomechanics and training
program should be taken into consideration when assessing the impact of
tendon insertion on sports performance. Working with a qualified sports
medicine professional can help athletes identify their strengths and
weaknesses and develop a training program tailored to their specific needs.
 Anatomical Planes and Major body movements

.
Human Strength & Power
● Strength - Strength refers to the ability of muscles to generate force against resistance. It is the
capacity of the body to lift, push, pull, or carry heavy loads or objects.
○ Iso metric - Isometric contraction occurs when a muscle is activated but remains in a fixed position and does not
change in length. This means that the muscle is contracting but not producing any movement.
○ Iso tonic - Isotonic contraction occurs when a muscle contracts and changes length to produce movement.
● Acceleration - The rate of change in velocity of an object or the body during a movement or
exercise. It is the increase in speed over time. (Change in velocity per unit time).
● Velocity - Velocity is a measure of the rate and direction of the motion of an object. It is a vector
quantity that combines the speed and direction of an object's movement, and is usually measured in
units of meters per second (m/s).
● Force -Force is defined as the product of mass and acceleration (F = ma).
○ Thus, testing an athlete’s force capabilities at various loads may provide more insight into the person’s sport-
specific capabilities and weaknesses, but needed sophisticated equipment.
Positive work and power
● Power – Explosive strength. In definition – Time rate of doing work, where
work is product of the force exerted on an object and the distance the object
moves in the direction in which the force is exerted.
○ Work (J) = Force x Displacement (N.m) Power (W) = work / time (J/s)
● Force – N (newton) / Distance – m (meter) / Time – s (sec) / Work – J (joules)
/ Power – W (watt).
○ Eg – 100 kg Deadlift for 10 rep, Displacement 2 m / rep – To find his work and power
○ Local acceleration due to gravity – 9.8 m/s2
○ F1 (gravity force) {9.8 x 100 = 980N} x F2 (Force accelerate) {2m x 100 = 200N}
○ Work positive – [980N + 200N] x 2 x 10 = 23600 J
○ Power positive – 23600J / 40 sec = 590 W (40 sec taken to complete the set).
Negative Work & Power
● Negative Rep – Decelerating the load.
● Acceleration = F/m {200N/100kg} = 2 m/s2
● Force removed to accelerate = 200N {2 x 100 x cos 0 deg}
● [Negative] Work = (980N + - 200N) x (-2m) x 10 reps = -15600J
● [Negative] Power = -15600J / 40 sec = -390 W
Angular Work and Power
● Angular displacement (radian – rad) – The angle in which the object rotate.
● Angular velocity (rad/s) – Rotational speed measured per second.
● Torque & work same unit N.m – Torque is the measure of the force that can
cause an object to rotate about an axis.
● Rotational work – Work = Torque x Angular displacement
● Strength – slow speed / Power – high velocity (Not true)– Power = Force x
velocity
● Strength is the capacity to exert force at any given velocity, and power is the
mathematical product of force and velocity at whatever speed.
● In sports both high velocity and low velocity strength is important – In American
Football (Offensive and defensive) compare with badminton player.
● Olympic lifting vs Power lifting – Snatch + Clean and jerk vs Back squat / Bench
press / Deadlift
Biomechanical Factor in human strength
● Neural control
● Muscle cross sectional area
● Arrangement of muscle fibres
● Muscle length
● Joint angle
● Muscle contraction velocity
● Joint angular velocity
● Body size
Neural control
● Muscle Recruitment - Is the process by which different motor units are activated
to produce a given level and type of muscle contraction.
● Rate Coding - Rate at which the motor units are fired
● Muscle force are greater
○ a) more motor units are involved in the contraction
○ b) the motor units are greater in size
○ c) the rate of firing is faster
● First few weeks of strength improvement is contributed by Neural adaptation.
Muscle cross sectional area
● The force a muscle can exert is related to its cross sectional area rather than
to its volume.
Arrangement of muscle fibers
Pennation angle
● https://www.youtube.com/
watch?v=1y-uzCfVENE
● Lower Pennation angle –
muscle with less capacity
to generate force, but
greater excursion.
● Greater Pennation angle –
muscle with greater
capacity to generate
force, but less excursion.
● Angle of Pennation may
vary depending on
hereditary factor.
Muscle length

● .
Joint angle
● .
Muscle contraction velocity
● The force capability of
muscle declines as the
velocity of contraction
increases. The relationship
is not linear; the decline in
force capability is steepest
over the lower range of
movement speeds
Joint angular velocity
Joint angular velocity
● .
● .
Strength to mass ratio
● For sprinting and jumping
● For weight class involved sports – Boxing / Weightlifting
○ In sport activities such as sprinting and jumping, the ratio of the strength of the
muscles involved in the movement to the mass of the body parts being
accelerated is critical. Thus, the strength-to-mass ratio directly reflects an athlete’s
ability to accelerate his or her body.
● Body Size
○ Body size increases, body mass increases more rapidly than does muscle
strength.(Smaller athletes has a higher strength to mass ratio than does the larger
athlete.
Sources of resistance to muscle contraction
● Gravity
● Inertia
● Friction
● Fluid resistance
● Elasticity
○ This section covers the force and power required to overcome these form of resistance.
Gravity
● Force (g) – mass (m) x ag (Local acceleration due to gravity).
● Application to resistance training

Exercise technique can affect the resistive

torque pattern during an exercise and can
shift stress among muscle groups.
Weight Stack machine / Free weights
● Pulley / cams / cable / gear /
○ Safety / Design flexibility / Easy of use
○ Advantage of free weights – Whole body training (Structural and weight bearing exercise) &
Simulation of real lift activities
○ Cam based machine and its disadvantage
Inertia
● Inertial force - In addition to gravitational force, a barbell or weight stack, when
accelerated, exerts inertial force on the athlete.
● Slow exercise with minimal acceleration of a given weight, an exercise involving
higher acceleration (an “explosive” exercise) provides greater resistance to the
muscles involved early in the range of motion and less resistance to the muscles
involved toward the end of the range of motion.
● Acceleration - Acceleration is characteristic of natural movements in sport and daily
life
● Olympic lifting exercise – High accelerations against heavy resistance (Clean & Jerk
/ Snatch) helps in desirable neuromuscular training effects.
● Acceleration and deceleration are characteristic of virtually all natural movements.
Inertia - Acceleration
● Acceleration is particular kind of movement pattern, training with accelerative
movements can provide specificity of training – In Olympic lifting.
● The bracketing technique, in which the athlete performs the sport movement with
● less than normal and greater than normal resistance, is another form of acceleration
training.
● training the neuromuscular system to operate within desired acceleration and speed
ranges. Although the principle of increasing or decreasing the load during a
movement as described has the theoretical basis for increasing acceleration capacity
through the aforementioned methods, (Shot putter - Low inertia / Heavy inertia)
Friction
● Friction is the resistive force encountered when one attempts to move an object while
it is pressed against another object. (Belt / brake pad resistive exercise)
● The coefficients of friction for initiating and for maintaining movement are different.
● Friction resisted exercise device requires a relatively high force to initiate
movement and a relatively constant force after movement has begun, no
matter what the movement speed. (sled push – sand / bare soil / dry grass /
wet grass)
● In sled - the coefficient of static friction is always greater than the coefficient of
sliding friction.
Fluid resistance
● The resistive force encountered by an object moving through a fluid (liquid or gas), or by a
fluid moving past or around an object or through an opening, is called fluid resistance.
● Swimming and Rowing – Fluid / Golf, Base ball, sprinter and discus throw – Air resistance
● Hydraulic training and pneumatic gas training
● Surface drag and form drag
Fluid cylinders provide resistance that increases with speed, they allow rapid
acceleration early in the exercise movement and little acceleration after higher speeds are
reached. Movement speed is thus kept within an intermediate range.
The lack of eccentric muscle action with fluid-resisted machines means that such
exercise probably does not provide optimal specificity of training for the many sport movements
that involve eccentric muscle actions (e.g., running, jumping, and throwing).
Elasticity
● A number of exercise devices, particularly those designed for home use, have elastic
components such as springs, bands, bows, or rods as their source of resistance. The
resistance provided by a standard elastic component is proportional to the distance it
is stretched.
● The problem with devices using elastic resistance is that every exercise movement
begins with low resistance and ends with high resistance. which show a substantial
drop-off in force capability toward the end of the range of motion.
● There are products that provide resistance to vertical jumping with elastic bands as a
means of developing jumping power.
Joint Biomechanics concerns in resistance training
● Back
● Shoulder
● Knee
● Wrist and Elbow
Explain the injuries
Conclusion
● Knowledge of how different types of exercise provide specific patterns of resistance
to the body can aid in developing safe and effective programs to suit the specific needs of
both athletes engaged in various sports and others who engage in resistance training for
enhancement of physical performance, health, sense of well-being, and self-confidence.