Movement Analysis 1

Which one of the following muscles is a main agonist when flexion occurs at the shoulder?

• A. Anterior deltoid

• B. Medial deltoid

• C. Posterior deltoid

Answer explanation

The anterior deltoid is the primary muscle responsible for shoulder flexion. It contracts to lift the arm forward, making it the main agonist in this movement, unlike the medial and posterior deltoids which are involved in other actions.

The image shows a squat. Identify the main agonist causing extension at the knee joint as the person stands up.

• Gastrocnemius

• Gluteals

• Hamstrings

• Quadriceps

Answer explanation

The quadriceps are the primary agonist responsible for extending the knee joint during the standing phase of a squat. They contract to straighten the leg, making them the correct choice.

The image shows how a gymnast holding a headstand. What is the 'type of muscle contraction' taking place while the gymnast is stationary?

• Isometric contraction

• Concentric contraction

• Eccentric contraction

• Isokinetic contraction

Answer explanation

The gymnast is holding a headstand, maintaining a position without movement. This requires muscle tension without changing length, which is characteristic of isometric contraction.

The image shows the drive phase of the leg action while running. Using the image, what is the main agonist at the right ankle as the athlete pushes off the ground?

• Gastrocnemius

• Quadricep

• Tibialis Anterior

• Hamstring

Answer explanation

The gastrocnemius is the main agonist at the ankle during the push-off phase of running, as it facilitates plantarflexion, propelling the athlete forward. The other options do not primarily act at the ankle in this context.

The figure below shows a games player running. The player's left leg is driving him forward. What is the movement occurring at the knee joint of the drive leg?

• Extension.

• Flexion

• Abduction

• Adduction

Answer explanation

The movement at the knee joint of the drive leg is extension, as the player pushes off the ground. This action straightens the knee, propelling the body forward.

The diagram shows a badminton serve. State the names of the bones forming the shoulder joint.

• Humerus and Scapula

• Femur and Tibia

• Radius and Ulna

• Fibula and Patella

Answer explanation

The shoulder joint is formed by the humerus (upper arm bone) and the scapula (shoulder blade). The other options include bones from different parts of the body, making 'Humerus and Scapula' the correct choice.

Select the names of the 'articulating bones' of the knee joint.

• Femur and Tibia

• Humerus and Radius

• Scapula and Clavicle

• Ulna and Radius

Answer explanation

The knee joint is formed by the articulation of the femur and tibia, making them the articulating bones of the knee. The other options involve bones from different joints.

Which muscle acts as the antagonist during elbow flexion?

• triceps (brachii).

• biceps (brachii).

• deltoid.

• latissimus dorsi.

Answer explanation

During elbow flexion, the biceps (brachii) contracts to bend the elbow, while the triceps (brachii) acts as the antagonist, relaxing to allow this movement. Therefore, the correct answer is the triceps (brachii).

What type of joint is the shoulder joint classified as?

• Ball and socket joint

• Hinge joint

• Pivot joint

• Saddle joint

Answer explanation

The shoulder joint is classified as a ball and socket joint because it allows for a wide range of motion in multiple directions, with the rounded head of the humerus fitting into the cup-shaped socket of the scapula.

During a bicep curl, which muscle is the primary agonist?

• Biceps brachii

• Triceps brachii

• Deltoid

• Latissimus dorsi

Answer explanation

The primary agonist during a bicep curl is the biceps brachii, as it is the muscle responsible for flexing the elbow and lifting the weight. The other muscles listed assist but are not the main movers in this exercise.