Biomechanics in sports

Biomechanics is the science of movement of a living body, including how muscles, bones, tendons, and ligaments work together to produce movement.

1. Biomechanics in Sports Submitted By: Ekta Kapri

2. Biomechanics is the study of the structure and function of biological systems by means of the methods of mechanics (the branch of physics involving analysis of the actions of forces). Biomechanics in sport incorporates detailed analysis of sport movements in order to minimize the risk of injury and improve sports performance. https://www.physio-pedia.com/Biomechanics_In_Sport

3. Sports biomechanics can simply be described as the physics of sports. In this subfield of biomechanics the laws of mechanics are applied in order to gain a greater understanding of athletic performance through mathematical modeling, computer simulation and measurement.

4. Mechanics is a branch of physics that is concerned with the description of motion/movement and how forces create motion/movement. Within mechanics there are two sub-fields of study: statics , which is the study of systems that are in a state of constant motion either at rest (with no motion) or moving with a constant velocity; dynamics , which is the study of systems in motion in which acceleration is present, which may involve kinematics kinetics

5. kinematics the study of the motion of bodies with respect to time, displacement, velocity, and speed of movement either in a straight line or in a rotary direction. kinetics the study of the forces associated with motion, including forces causing motion and forces resulting from motion.

6. Application Generally the primary goals of sports biomechanics are: Improve athletic performance by identifying and applying optimal technique. Prevent injury and speed up recovery. optimal technique for enhancing sports performance    The assessment of muscular recruitment and loading  The analysis of sport and exercise equipment e.g., shoes, surfaces and rackets. Biomechanics is utilized to attempt to either enhance performance or reduce the injury risk in the sport and exercise tasks examined.

7. Principles of Biomechanics Forces and Torques A force is simply a push or pull and it changes the motion of a body segment. Motion is created and modified by the actions of forces (mostly muscle forces, but also by external forces from the environment). When force rotates a body segment, this effect is called a torque or moment of force.   Example - Muscles create a torque to rotate the body segments in all tennis strokes. In the service action internal rotation of the upper arm, so important to the power of the serve, is the result of an internal rotation torque at the shoulder joint caused by muscle actions. To rotate a segment with more power a player would generally apply more muscle force.

8. 2. Newton’s Laws of Motion Law of Inertia -  Newton’s First Law of inertia states that objects tend to resist changes in their state of motion. An object in motion will tend to stay in motion and an object at rest will tend to stay at rest unless acted upon by a force.   Example - The body of a player quickly sprinting down the field will tend to want to retain that motion unless muscular forces can overcome this inertia or a skater gliding on ice will continue gliding with the same speed and in the same direction, barring the action of an external force.

9. Law of Acceleration -  Newton’s Second Law precisely explains how much motion a force creates. The acceleration (tendency of an object to change speed or direction) an object experiences is proportional to the size of the force and inversely proportional to the object’s mass (F = ma).  Example - When a ball is thrown, kicked, or struck with an implement, it tends to travel in the direction of the line of action of the applied force. Similarly, the greater the amount of force applied, the greater the speed the ball has. If a player improves leg strength through training while maintaining the same body mass, they will have an increased ability to accelerate the body using the legs, resulting in better agility and speed.

10. Law of Reaction -  The Third Law states that for every action (force) there is an equal and opposite reaction force. This means that forces do not act alone, but occur in equal and opposite pairs between interacting bodies.  Example - The force created by the legs “pushing” against the ground results in ground reaction forces in which the ground “pushes back” and allows the player to move across the court (As the Earth is much more massive than the player, the player accelerates and moves rapidly, while the Earth does not really accelerate or move at all). This action-reaction also occurs at impact with the ball as the force applied to the ball is matched with an equal and opposite force applied to the racket/body.

11. 3. Momentum Newton’ Second Law is also related to the variable momentum, which is the product of an object’s velocity and mass . Momentum is a commonly used term in sports. A team that has the momentum is on the move and is going to take some effort to stop. A team that has a lot of momentum is really on the move and is going to be hard to stop . Momentum is a physics term; it refers to the quantity of motion that an object has. A sports team that is on the move has the momentum. If an object is in motion ( on the move ) then it has momentum. p = m • v ( kg•m /s) where m is the mass and v is the velocity.  

12. Linear Momentum Linear momentum is momentum in a straight line e.g. linear momentum is created as the athlete sprints in a straight line down the 100m straight on the track. Angular Momentum Angular momentum is rotational momentum and is created by the rotations of the various body segments e.g. The open stance forehand uses significant angular momentum.  In tennis, the angular momentum developed by the coordinated action of body segments transfers to the linear momentum of the racquet at impact.

13. 4. Centre of Gravity The Center of Gravity (COG) is an imaginary point around which body weight is evenly distributed. The center of gravity of the human body can change considerably because the segments of the body can move their masses with joint rotations. This line of gravity is important to understand and visualise when determining a person's ability to successfully maintain balance. When the line of gravity falls outside the Base of Support (BOS), then a reaction is needed in order to stay balanced.

14. The center of gravity can be located within or outside the body depending on the body's configuration and position; it is inside an object when the object is uniform and outside the object when it is not uniform.

15. https://www.slideshare.net/shimaa2022/center-of-gravity

16. 5. Balance Balance is the ability of a player to control their equilibrium or stability. You need to have a good understanding of both static and dynamic balance: Static Balance The ability to control the body while the body is stationary. It is the ability to maintain the body in some fixed posture. Static balance is the ability to maintain postural stability and orientation with center of mass over the base of support and body at rest. Dynamic Balance  The ability to control the body during motion. Defining dynamic postural stability is more challenging, Dynamic balance is the ability to transfer the vertical projection of the center of gravity around the supporting base of support.

17. Normal walk requirement

18. 6. Friction Friction can be defined as the resistance to motion of two moving objects or surfaces that touch. When both the surfaces are smooth, the force of friction reduces to almost zero. Three types of friction are Static Friction is a force that keeps an object at rest. It must be overcome to start moving the object. If a small amount of force is applied to an object, the static friction has an equal magnitude in the opposite direction. Kinetic Friction is a force that acts between moving surfaces. An object that is being moved over a surface will experience a force in the opposite direction as its movement.

19. 7. Axes & Plane Plane is an imaginary, flat surface passing through the body organ or plane is the surface on which the movement occurs. There are following types of planes: a ) Sagittal or Medial plane: dividing the body into left and right halves. It is also known as anteroposterior plane. Most of the sports and exercise movements that are two dimensional, such as running, long jumping and somersault take place in this plane. b) Frontal or Coronal plane: passes from left to right dividing the body into posterior to anterior halves (front and back). c) Transverse or Horizontal plane : divides the body into top and bottom halves. https://www.physio-pedia.com/Biomechanics_In_Sport

20. An axis is a straight line around which an object rotates. Movements at the joints of human muscoskeletal system are mainly rotational and take place about a line perpendicular to the plane in which they occur. This line is known as axis of rotation. There are following types of axes of rotation: a) Sagittal axis: The sagittal axis passes horizontally from posterior to anterior. It is formed by the intersection of the sagittal and transverse plane. Sagittal axis passes from front to back. b) Frontal axis: The frontal axis passes horizontally from left to right. It is formed by the intersection of frontal and horizontal plane. Frontal axis passes from side to side . c) Vertical axis: The vertical axis passes vertically from inferior to superior. It passes straight through the top of the head down between feet . It is formed by the intersection of sagittal and frontal plane. It is also known as longitudinal axis.

21. Types  of movements There are various types of movement in body parts which can be divided in four types i.e. gliding & angular movements, circumduction & rotation and few other movements. 1. Gliding movements: Gliding movements is the simplest kind of movement that can take place in a joint, one surface gliding or moving over another without any angular or rotator movement.

22. 2. Angular movement : are produced when the angle between the bones of a joint changes.By angular movement the angle between the two bones increased or decreased. The various movements which fall under angular movements are described below: Flexion: Bending parts at a joint so that the angle between them decreases and parts come closer together (bending the lower limb at the knee). Extensions: Straightening parts so that the angle between them increases and parts moves farther apart (straightening the lower limb at the knee). Abduction means moving a part away from the midline (lifting the upper limb horizontally to form a right angle with the side of the body) Adduction means moving a part towards the midline ( returning the upper limb from the horizontal position to the side of the body).

23. https://www.physio-pedia.com/Cardinal_Planes_and_Axes_of_Movement

24. Running Biomechanics Running is similar to walking in terms of locomotors activity. Running requires: Greater balance Greater muscle strength Greater joint range of movement https://www.physio-pedia.com/Running_Biomechanics

25. Major  muscles involved in running The major muscles involved in running are described below: Glutes : these muscles stabilize your hips and legs. These muscles work with hamstring muscles and help in hip flexors. Quads : Quads propel you forward and help straighten out the leg in front so that it can make a good contact with the surface of ground. Calves : these muscles give you spring in your step and at the same time these muscles act as shock absorbers. Hamstrings : As you move forward, the action switches to your hamstrings, the muscles at the back of your thigh muscles. These muscles helps you in pulling the leg back behind and give you strength to propel your body forward. Core muscles: Strong abs and back are really important because they keep yours posture upright and overall form good. These muscles play a significant role in running. Biceps: biceps also play a vital role in running. Biceps maintain a bent arm and help in swinging your arms back and forth while running.

26. Gait Analysis • Study of human locomotion • Walking and running • Walking is a series of gait cycles – A single gait cycle is known as a STRIDE

27. Stance Phase of Gait • When the foot is contact with the ground only • Propulsion phase • Stance phase has 5 parts: – Initial Contact (Heel Strike)(1) – Loading Response (Foot Flat)(2) – Midstance (2) – Terminal Stance (3) – Toe Off (Pre-Swing) (4)