Welcome to Movement Analysis!

Ever wondered how a sports scientist describes a perfect football kick or a netball shot? It’s not just about "moving your leg" or "throwing the ball." In this chapter, we learn the professional language used to break down every movement the human body makes. By the end of these notes, you will be able to analyze any sporting action using the correct articulating bones, muscle actions, and planes of movement.

Note: This chapter is a fundamental part of "Applied anatomy and physiology" and links closely to the Biomechanics section you will study later!

1. The Basics: Joints and Bones

To analyze movement, we first need to know which bones are meeting at the joint. These are called articulating bones. In the AQA specification, we focus on five key joints:

  • Shoulder: Articulating bones are the scapula and humerus.
  • Hip: Articulating bones are the pelvis and femur.
  • Elbow: Articulating bones are the humerus, radius, and ulna.
  • Knee: Articulating bones are the femur and tibia.
  • Ankle: Articulating bones are the tibia, fibula, and talus.

Quick Tip: Don't worry if you forget the fibula or radius at first—just remember that joints are where two or more bones meet to allow movement!

2. Muscle Contractions: How Muscles Work

Muscles move our bones by pulling on them. However, they don't always change length in the same way. There are two main types of contraction you need to know:

Isotonic Contraction

This is when the muscle changes length while under tension. There are two "sub-types" here:

  • Concentric: The muscle shortens under tension. Example: The "up" phase of a bicep curl.
  • Eccentric: The muscle lengthens under tension. This often acts as a "brake" to control movement. Example: Lowering the weight slowly during a bicep curl.

Isometric Contraction

This is when the muscle is under tension but does not change length. The joint stays still. Example: Holding a "plank" position or a rugby scrum.

Key Takeaway:

Agonist = The "Prime Mover" (the muscle doing the main work).
Antagonist = The muscle that relaxes to allow the movement to happen.

3. Planes and Axes: The "GPS" of Movement

This is often the part students find trickiest, but there is a simple trick! Think of a Plane as a sheet of glass slicing through the body, and an Axis as a rod or pin that the body rotates around.

A. Sagittal Plane and Transverse Axis

Imagine two walls on either side of you. You can only move forward and backward. This "forward and backward" movement happens in the Sagittal Plane around a Transverse Axis (an imaginary pin going through your hips from side to side).

Movements in this plane:

  • Flexion: Decreasing the angle at a joint (e.g., bending the knee).
  • Extension: Increasing the angle at a joint (e.g., straightening the arm).
  • Hyperextension: Extending a joint beyond its normal straight position (e.g., moving the arm back behind the body at the shoulder).
  • Dorsi-flexion: Pulling the toes up toward the shin (ankle joint).
  • Plantar-flexion: Pointing the toes down away from the shin (ankle joint).

B. Frontal Plane and Sagittal Axis

Imagine you are pressed between two sheets of glass (one in front, one behind). You can only move side-to-side. This is the Frontal Plane, and the movement rotates around the Sagittal Axis (an imaginary pin going through your belly button from front to back).

Movements in this plane:

  • Abduction: Moving a limb away from the midline of the body. (Think: "Abducting" or taking something away).
  • Adduction: Moving a limb toward the midline of the body. (Think: "Adding" it back to the body).

C. Transverse Plane and Longitudinal Axis

This involves twisting or rotational movements. The Transverse Plane cuts the body into top and bottom halves. The Longitudinal Axis is like a pole running from your head down to your feet that you spin around.

Movements in this plane:

  • Horizontal Abduction: Moving the arm away from the chest while it is held parallel to the ground.
  • Horizontal Adduction: Moving the arm toward the chest while it is held parallel to the ground (e.g., a chest fly in the gym).

4. Summary Table for Revision

Use this table to quickly check which movements belong to which plane and axis. This is "gold dust" for exam marks!

Plane Axis Examples of Movement
Sagittal Transverse Flexion, Extension, Hyperextension, Plantar-flexion, Dorsi-flexion.
Frontal Sagittal Abduction, Adduction.
Transverse Longitudinal Horizontal Abduction, Horizontal Adduction.

5. Common Mistakes to Avoid

  • Mixing up the Ankle movements: Remember Plantar-flexion = Pointing the toes. Dorsi-flexion = toes to De ceiling (well, the sky!).
  • Forgetting the Axis: In the exam, you are often asked for both the plane and the axis. They always come in pairs. S-T (Sagittal-Transverse), F-S (Frontal-Sagittal), and T-L (Transverse-Longitudinal).
  • Identifying the wrong Agonist: Always look at the joint action first. If the elbow is flexing, the biceps must be the agonist. If it is extending, the triceps take over.

Did you know? When you perform a "squat," your hip, knee, and ankle joints are all moving in the Sagittal Plane around a Transverse Axis. It is one of the most common planes used in sport!

Quick Review Quiz

1. What are the articulating bones of the shoulder joint?
(Answer: Scapula and Humerus)

2. Which type of contraction involves the muscle lengthening under tension?
(Answer: Isotonic Eccentric)

3. If a gymnast performs a "cartwheel," which plane and axis are they moving in?
(Answer: Frontal Plane and Sagittal Axis)

Don't worry if the planes and axes feel confusing at first—try standing up and performing the movements while imagining the "glass panes" and "pins." It will click!