What does the biomechanics and movement analysis module cover?

It covers four areas: force, speed and Newton's three laws of motion applied to sporting actions; the three classes of lever in the body and how to calculate mechanical advantage; the three planes and three axes of movement and how they describe rotations such as somersaults and twists; and the factors affecting the flight path of a projectile, namely the angle, speed and height of release. Biomechanics applies the laws of physics to explain and improve human movement in sport.

How do you calculate the mechanical advantage of a lever?

Mechanical advantage is the effort arm divided by the load arm, where the effort arm is the distance from the fulcrum to the effort and the load arm is the distance from the fulcrum to the load. A mechanical advantage greater than 1 means the lever multiplies force (good for lifting heavy loads), while a value less than 1 means it sacrifices force for a greater range and speed of movement. Most levers in the body are third class, with a mechanical advantage less than 1, favouring speed and range over force.

What are the three planes and three axes of movement?

The three planes are the sagittal plane (divides the body into left and right, for forward and backward movements), the frontal plane (divides front and back, for side-to-side movements) and the transverse plane (divides top and bottom, for rotations). Each plane has a matching axis about which rotation occurs: the frontal (transverse) axis, the sagittal axis and the vertical (longitudinal) axis. A somersault occurs in the sagittal plane about the frontal axis, and a twist in the transverse plane about the vertical axis.

What factors affect the flight path of a projectile in sport?

Three release factors decide the flight path of a projectile such as a shot, javelin or long-jumper: the angle of release, the speed (velocity) of release and the height of release. A greater release speed sends it further; the optimum angle is around 45 degrees when release and landing heights are equal, but is lower when the object is released from above ground level. Air resistance and gravity also shape the path, which is a curved parabola because gravity acts downward throughout the flight.

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Biomechanics and Movement Analysis: O-Level Exercise and Sports Science (SEAB 6081) module overview of force, levers, planes and axes, and projectile motion

An O-Level Exercise and Sports Science overview of biomechanics and movement analysis (SEAB 6081). How force, speed and Newton's laws explain sporting motion, the three lever systems and mechanical advantage, the planes and axes of movement, and the factors affecting a projectile's flight path, with links to every dot point.

Generated by Claude Opus 4.86 min readSEAB-6081Updated 2026-06-13

Reviewed by: AI editorial process; not yet individually human-reviewed

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What this module is about
Force, speed and Newton's laws
Levers in the body
Planes and axes of movement
Projectile motion
Check your knowledge

What this module is about

Biomechanics applies the laws of physics to human movement, and the O-Level Exercise and Sports Science syllabus (SEAB 6081) keeps it grounded in real sport: why a sprinter accelerates, why the body's levers favour speed over force, how to describe a somersault precisely, and what makes a javelin fly far. This module appears in the written theory paper and rewards correct technical vocabulary and clean calculation. This overview links the four dot points; work each in full for the worked answers and practice questions.

See the complete set for this subject at /sg-o-level/sports-science/syllabus.

Force, speed and Newton's laws

Start with the physics of motion. The force and motion in sport page applies force, speed and Newton's three laws (inertia, force equals mass times acceleration, and action-reaction) to sprinting, throwing and contact. The action-reaction law in particular explains how a runner pushes back on the ground to be driven forward.

Levers in the body

The body moves through lever systems, and the levers in the body page classifies them as first, second and third class according to the order of fulcrum, load and effort. It also shows how to calculate mechanical advantage to explain the trade-off between force and range of movement. This links straight back to the muscular system, because the muscle supplies the effort and the bone is the lever.

Planes and axes of movement

To describe a movement precisely you need its plane and axis. The planes and axes of movement page sets out the three planes (sagittal, frontal, transverse) and the three axes (frontal, sagittal, vertical), and shows how they combine to describe rotations such as somersaults and twists. Examiners reward the exact pairing, for example a somersault in the sagittal plane about the frontal axis.

Projectile motion

Finally, the projectile motion page explains the factors that decide how far and high a projectile travels, the angle, speed and height of release, and why a projectile follows a curved parabolic path under the constant downward pull of gravity.

Calculating the mechanical advantage of a lever

A question gives the effort arm and load arm of a lever and asks for the mechanical advantage and what it means. Take a standing calf raise, a second-class lever where the effort arm (fulcrum at the toes to the calf muscle effort) is 20 cm and the load arm (fulcrum to the body weight over the ankle) is 8 cm.

Step 1: Recall the formula

Mechanical advantage is the effort arm divided by the load arm:

MA = \frac{\text{effort arm}}{\text{load arm}}

Step 2: Substitute the values

MA = \frac{20}{8} = 2.5

Step 3: Interpret the result

Because the mechanical advantage is greater than 1, the lever multiplies force: a relatively small muscular effort can lift a larger load. This is the signature of a second-class lever, such as the calf raise, where the load sits between the fulcrum and the effort, so the body can raise its full weight efficiently. State both the number and its meaning to earn full marks.

Check your knowledge

A mix of recall, application and calculation questions covering the module. Attempt them under timed conditions, then check against the solutions.

State Newton's third law and give one example from sport. (2 marks)
A lever has an effort arm of 30 cm and a load arm of 10 cm. Calculate the mechanical advantage and state what it means. (2 marks)
Name the plane and axis in which a gymnast performs a somersault. (2 marks)
State the three factors that affect the flight path of a projectile. (3 marks)
Explain why most levers in the body are third class even though they do not multiply force. (2 marks)

Solutions

Q1: Newton's third law states that for every action there is an equal and opposite reaction. Example: a sprinter pushes backward and downward on the blocks (action), and the ground pushes the sprinter forward and upward with an equal and opposite force (reaction), driving them out of the blocks.
Q2: Mechanical advantage = effort arm divided by load arm = $30 \div 10 = 3$ . Because it is greater than 1, the lever multiplies force, so a smaller effort can move a larger load.
Q3: A somersault is performed in the sagittal plane about the frontal (transverse) axis.
Q4: The angle of release, the speed (velocity) of release, and the height of release.
Q5: Third-class levers (effort between the fulcrum and the load, as at the elbow) have a mechanical advantage less than 1, so they sacrifice force, but in return they give a large range and speed of movement at the end of the limb. Sport needs fast, wide-ranging limb movement (throwing, kicking, sprinting), so the speed and range matter more than raw force.

Sources & how we know this

Singapore-Cambridge GCE Ordinary Level Exercise and Sports Science (Syllabus 6081) — Singapore Examinations and Assessment Board (2026)