Sample Answer

Introduction:

• Competitive swimming performance is significantly influenced by the application of fluid mechanics principles, particularly drag forces, buoyancy, and how the body’s systems work together to optimise movement in water.

Drag Reduction:

• Drag reduction is essential for swimming efficiency; swimmers adopt a streamlined body position by contracting abdominal muscles to elevate hips and align the body horizontally.
• Streamlined positioning minimises frontal resistance by reducing the body’s cross-sectional area exposed to water, allowing movement with less resistance.
• Proper hand positioning during the pull phase creates lift forces similar to an airplane wing; slightly cupped hands with fingers together maximise water grip and propulsion.
• The relationship between velocity and drag is exponential; as swimming speed increases, water resistance increases at a greater rate, requiring progressively more force production to maintain speed.

Buoyancy Optimisation:

• Buoyancy optimisation requires understanding the relationship between centre of gravity and centre of buoyancy; swimmers with greater muscle mass typically have lower natural buoyancy due to muscle density.
• To enhance buoyancy, swimmers keep their lungs partially inflated, allowing the respiratory system to assist with flotation by decreasing overall body density.
• Body composition significantly impacts buoyancy; individuals with higher percentages of body fat typically float more easily as fat is less dense than water.
• In freestyle, rotation of the body along the longitudinal axis enhances buoyancy while facilitating easier breathing and more effective arm pull.

Interrelationship Between Body Systems:

• The muscular and skeletal systems work together to maintain proper alignment; core muscles stabilise the spine and pelvis, while the shoulder joint enables proper arm positioning.
• The cardiorespiratory system must deliver sufficient oxygen to working muscles while simultaneously contributing to buoyancy through lung inflation.
• The nervous system coordinates precise movements through proprioception, allowing the swimmer to maintain optimal body position despite not being able to see their alignment.
• Elite swimmers continuously adjust their technique based on changing conditions (fatigue, race stage) to maintain optimal efficiency between muscle activation patterns and fluid mechanics principles.

Conclusion:

• Successful competitive swimmers understand and apply these biomechanical principles to minimise energy expenditure while maximising propulsion, resulting in improved race times and reduced fatigue during competition.

Sample Answer

• Gymnasts manipulate their centre of gravity relative to their base of support to maintain balance during various movements.
• During a handstand, the gymnast must position their centre of gravity directly above their base of support (hands) by engaging shoulder, arm, and core muscles to maintain alignment.
• To prevent falls, gymnasts widen their base of support during skill transitions by positioning hands/feet further apart, lowering their centre of gravity closer to the floor.
• When executing a forward roll, gymnasts tuck their chin to chest, contracting neck muscles and flexing the cervical spine to protect the neck and maintain a smooth roll along the spine.
• During landings from tumbling passes, gymnasts bend at the knee, hip, and ankle joints to absorb impact forces gradually rather than suddenly.
• This controlled absorption of force through muscular eccentric contraction of the quadriceps and gluteal muscles reduces stress on joints and lowers injury risk.
• For dynamic movements, gymnasts shift their line of gravity to the edge of their base of support, creating controlled instability that facilitates efficient movement initiation.
• In spinning elements like pirouettes, gymnasts contract core muscles to stabilise their torso while maintaining a narrow base of support around a vertical axis.
• Efficient weight transfer during complex sequences requires precise control of the centre of gravity through coordinated muscular contractions and joint movements.

Sample Answer

• In a sprint start, the athlete applies force against the starting blocks through muscular contraction, primarily using the quadriceps, hamstrings, and gluteal muscles.
• These muscles contract forcefully, pulling on the femur, tibia, and fibula bones to generate powerful extension at the hip and knee joints.
• The ankle joint plantar flexes through contraction of the gastrocnemius and soleus muscles, pushing against the blocks to create a reaction force.
• According to Newton’s Third Law, the force applied to the blocks results in an equal and opposite reaction force, propelling the athlete forward.
• The arm muscles (biceps and triceps) contract to create a counterbalance movement, generating additional force through the shoulder joint rotation.
• The abdominal muscles contract to maintain core stability, allowing efficient force transfer from lower body to upper body.

\(A\)

\(C\)