2025 IB DP Sports, Exercise and Health Science 模擬試題連答案詳解

During the downward phase of a squat, the knee flexes. To control the rate of descent against gravity, the knee extensors (quadriceps femoris) must contract eccentrically (lengthening under tension) to slow down the knee flexion movement.

Award 1 mark for selecting option A, which correctly identifies the eccentric contraction of the quadriceps to control flexion.

The standard energy values per 100 grams of macronutrients taught in SEHS are: Carbohydrate yield is approximately \(1760\text{ kJ}\), Lipid (Fat) is approximately \(4000\text{ kJ}\), and Protein is approximately \(1720\text{ kJ}\).

Award 1 mark for identifying the correct energy values in Option A.

Cardiovascular drift is characterized by a gradual decrease in stroke volume (due to loss of blood volume through sweating and increased blood flow to the skin) and a compensatory increase in heart rate to maintain a constant cardiac output.

Award 1 mark for identifying the combination of decreasing stroke volume and increasing heart rate.

Because the information is given by an external observer (the coach), it is extrinsic feedback. Because it describes the execution and mechanics of the movement (the stride pattern) rather than the overall outcome or performance score, it represents Knowledge of Performance.

Award 1 mark for identifying the feedback as knowledge of performance and extrinsic feedback.

Newton's Third Law of Motion states that for every action, there is an equal and opposite reaction. If the action is the sprinter pushing backward against the blocks with a force of \(800\text{ N}\), the reaction force is the blocks exerting an equal forward force of \(800\text{ N}\) on the sprinter's feet.

Award 1 mark for identifying the equal and opposite forward force of \(800\text{ N}\) acting on the sprinter.

Acute injuries have a sudden onset and are typically caused by a single traumatic mechanism, such as a hamstring muscle strain sustained during a rapid sprint. Chronic or overuse injuries, such as tendinopathy or shin splints, develop gradually over time due to repetitive loading.

Award 1 mark for identifying the hamstring strain as the acute injury.

Self-Determination Theory postulates that satisfying three basic psychological needs—autonomy (feeling control over one's behavior), competence (feeling effective in actions), and relatedness (feeling connected to and cared for by others)—is critical for developing intrinsic motivation.

Award 1 mark for identifying autonomy, competence, and relatedness.

Somatic anxiety refers to the physiological/physical manifestation of stress and anxiety, which includes symptoms such as an increased heart rate, sweating, and muscle tension. Cognitive anxiety, by contrast, represents the mental/cognitive aspects such as worrying thoughts or negative expectations.

Award 1 mark for identifying somatic anxiety as the correct term for physiological symptoms of anxiety.

During muscle contraction, myosin cross-bridges pull actin filaments toward the center of the sarcomere (the M-line). This causes the H-zone (the region containing only thick myosin filaments) and the I-band (the region containing only thin actin filaments) to shorten. The A-band remains at a constant length.

Award 1 mark for the correct option A. No partial marks.

In untrained individuals, stroke volume increases during initial increments of exercise but reaches a plateau at around 40% to 60% of maximum aerobic capacity. Beyond this point, any further increase in cardiac output is achieved almost entirely by increases in heart rate, which continues to rise linearly with exercise intensity.

Award 1 mark for identifying the plateau of stroke volume and the linear increase of heart rate (Option A).

Carbohydrates are digested into glucose and primarily stored in the form of glycogen. The main storage depots for glycogen are skeletal muscle (for local energy production) and the liver (to maintain blood glucose homeostasis).

Award 1 mark for selecting Option A.

Newton's Third Law states that for every action, there is an equal and opposite reaction. When the athlete exerts a backward and downward force onto the starting blocks/ground, the blocks/ground exert an equal and opposite forward and upward reaction force onto the runner, propelling them forward.

Award 1 mark for Option A as the correct application of Newton's Third Law.

The cognitive stage of learning is the initial phase where the performer seeks to understand the requirements of the movement. It is characterized by a high number of errors, uncoordinated performance, and heavy reliance on external feedback and visual cues to correct performance.

Award 1 mark for Option A.

An acute injury occurs suddenly and is associated with a specific traumatic event (such as a sudden tear of a muscle fiber during a rapid contraction). Chronic injuries (like tendinopathy, stress fractures, and tendonitis) develop gradually over time due to repetitive microtrauma.

Award 1 mark for identifying the hamstring tear as the acute injury (Option A).

Self-Determination Theory (SDT) posits that there are three basic, universal psychological needs that fuel intrinsic motivation: Autonomy (the need to feel in control of one's own behavior), Competence (the need to feel effective in performing tasks), and Relatedness (the need to feel connected with others).

Award 1 mark for Option A.

Somatic anxiety refers to the physical symptoms of anxiety that arise from physiological arousal, including increased heart rate, muscle tension, sweating, and nausea. Cognitive anxiety, on the other hand, involves mental symptoms like negative thoughts, apprehension, and concentration issues.

Award 1 mark for identifying physical symptoms of anxiety (Option A).

During the downward phase of a squat, gravity acts to flex the knees and hips. To control this movement and prevent collapsing, the agonist muscles (the quadriceps, which act as knee extensors) must lengthen while under tension. This is an eccentric contraction.

Award [1] mark for the correct option B. No partial marks.

Cardiovascular drift is characterized by a progressive decrease in stroke volume (due to fluid loss via sweat and the redistribution of blood to the skin for cooling) accompanied by a compensatory gradual increase in heart rate to maintain a constant cardiac output.

Award [1] mark for the correct option B. No partial marks.

Video playback of a movement focus on the execution and technique of the movement itself (how the skill was performed), rather than the quantitative outcome of the jump (how high they jumped). Therefore, it is classified as Knowledge of Performance (KP).

Award [1] mark for the correct option C. No partial marks.

Lipids (fats) have an energy density of approximately \(9\text{ kcal/g}\) (\(37\text{ kJ/g}\)), which is more than double that of carbohydrates or proteins (approx. \(4\text{ kcal/g}\)). Lipids are also the primary substrate utilized during prolonged, low-intensity aerobic exercise.

Award [1] mark for the correct option C. No partial marks.

Topspin causes the top surface of the ball to rotate against the airflow, slowing the air down (high pressure). The bottom surface rotates in the same direction as the airflow, speeding it up (high velocity and low pressure). The resulting pressure differential pushes the ball downward, causing it to dip quickly.

Award [1] mark for the correct option B. No partial marks.

The Inverted-U Hypothesis proposes that optimal arousal depends on task complexity and skill level. Complex motor skills (requiring fine motor control and high decision-making) and novice athletes (who have not automated the movement) require lower levels of arousal to avoid performance deterioration.

Award [1] mark for the correct option B. No partial marks.

The interactionist approach suggests that behavior and personality are a result of the interaction between stable personal traits and the specific situational environment in which the individual is placed.

Award [1] mark for the correct option C. No partial marks.

A sprain is specifically defined as a stretch, twist, or tear of a ligament (the fibrous tissue connecting bone to bone). A strain refers to injuries affecting muscle fibers or tendons.

Award [1] mark for the correct option B. No partial marks.

According to the sliding filament theory of muscle contraction, the A-band, which corresponds to the length of the thick myosin filaments, does not shorten or change length. The I-band (actin-only region) and the H-zone (myosin-only region) both shorten as actin filaments are pulled toward the M-line, which also shortens the overall sarcomere length.

Award 1 mark for the correct option C.

Lipids play vital structural and regulatory roles in the human body. They form the phospholipid bilayer of cell membranes and serve as precursors for essential steroid hormones (such as testosterone and estrogen). Carbohydrates, not lipids, are the primary rapid fuel source during high-intensity anaerobic activities, and calcium ions stimulate muscle contraction.

Award 1 mark for the correct option B.

At the onset of exercise, the rapid initial increase in heart rate (up to approximately 100 beats per minute) is primarily mediated by the withdrawal of parasympathetic (vagal) tone. Subsequent increases beyond this rate are driven by sympathetic nervous activation and circulating catecholamines like adrenaline.

Award 1 mark for the correct option B.

The feedback is 'terminal' because it is received after the movement has been completed. It is 'knowledge of performance' because it focuses on the specific biomechanical technique and movement characteristics (hip position over the bar) rather than the outcome of the movement (whether the bar was cleared or not, which would be knowledge of results).

Award 1 mark for the correct option C.

Newton's Third Law of Motion states that for every action, there is an equal and opposite reaction. When the sprinter pushes against the starting blocks (action), the blocks push back on the sprinter with equal force in the opposite direction (reaction), propelling the runner forward.

Award 1 mark for the correct option C.

An acute, macrotraumatic injury occurs suddenly due to a single, high-force event. A ligament sprain resulting from an abrupt, traumatic twisting movement is an example of an acute macrotrauma to soft tissue. Stress fractures, Achilles tendinopathy, and shin splints are chronic, microtraumatic overuse injuries.

Award 1 mark for the correct option C.

Isometric contraction: Muscle produces force without changing length. Isotonic contraction: Muscle changes length during force production. Concentric: Muscle shortens while producing force. Eccentric: Muscle lengthens while producing force. Real-world example: Lowering phase of a squat where the quadriceps contract eccentrically to control descent.

[0.5 marks] Define isometric contraction (muscle tension with constant length). [0.5 marks] Define concentric contraction (muscle shortens under tension). [0.5 marks] Define eccentric contraction (muscle lengthens under tension). [0.5 marks] Clearly distinguish that isotonic involves length changes while isometric does not. [0.5 marks] Provide a correct sporting example of eccentric contraction (e.g., quadriceps during downhill running, lowering a dumbbell during a curl).

A double-blind study prevents expectations from altering the objective results. The lack of knowledge prevents the placebo effect in athletes and stops researchers from giving preferential encouragement or subjective bias during performance measurements.

[0.5 marks] Identifies that neither participant nor researcher knows group allocation. [1.0 marks] Explains reduction of participant bias (e.g., prevents placebo effect / psychological influence on performance). [1.0 marks] Explains reduction of researcher bias (e.g., prevents coaching differences, subjective interpretation of effort/results).

Distributed practice structures sessions with rests to maintain high-quality movement patterns and focus. Variable practice challenges schema theory by changing distance/angle to mimic game conditions, enhancing long-term retention and motor learning adaptability.

[1.0 marks] Distributed practice: describes practice with rest/intervals (0.5) applied specifically to jump shot rest/feedback (0.5). [1.0 marks] Variable practice: describes practicing under varied conditions (0.5) applied specifically to shooting from different distances/angles (0.5). [0.5 marks] Explains cognitive/motor benefit (e.g., prevents fatigue for distributed, or improves schema/adaptability for variable).

At exercise onset, HR and SV rise sharply. HR increases due to neural activation. SV increases due to stronger heart contraction and venous return. Cardiac output \(Q = \text{HR} \times \text{SV}\) increases and then all parameters level off (plateau) once oxygen supply matches the metabolic demand of the tissues (steady-state).

[1.0 marks] Explains heart rate increase and plateau at steady-state. [1.0 marks] Explains stroke volume increase and plateau (mentioning increased contractility or venous return). [0.5 marks] Connects both to the increase and stabilization of cardiac output (\(Q = \text{HR} \times \text{SV}\)).

Dehydration decreases blood plasma volume, raising heart rate to compensate for lower stroke volume (cardiovascular drift). Reduced sweat production restricts the body's primary heat-dissipation mechanism, driving up core temperature and expediting physical exhaustion.

[1.0 marks] Identifies decrease in plasma volume leading to decreased stroke volume / increased blood viscosity. [0.5 marks] Identifies cardiovascular drift (compensatory increase in heart rate to maintain cardiac output). [1.0 marks] Explains reduced sweating/skin blood flow causing impaired thermoregulation and elevated core body temperature.

According to Newton's third law, the force applied by the jumper's foot to the ground is met with an equal and opposite force by the ground on the jumper. Applying a large downward force generates a large upward ground reaction force, allowing the athlete to clear the crossbar.

[0.5 marks] States Newton's third law (action and reaction are equal and opposite). [1.0 marks] Explains the action force (athlete pushing down/backwards into the runway/ground). [1.0 marks] Explains the reaction force (ground pushing upwards/forwards on the athlete, driving them into the air).

Acute injuries are characterized by sudden onset, severe pain, and trauma (e.g., ankle sprain). Chronic injuries result from prolonged repetitive stress, showing a gradual onset of pain and deterioration (e.g., shoulder tendonitis).

[1.0 marks] Explains distinction: acute is sudden/traumatic onset (0.5) whereas chronic is gradual/overuse over time (0.5). [0.75 marks] Provides a valid acute joint injury example (e.g., ACL tear, ankle sprain from rolling). [0.75 marks] Provides a valid chronic joint injury example (e.g., patellar tendinopathy, shoulder impingement, tennis elbow).

Calcium ions unblock binding sites by binding to troponin and shifting tropomyosin. ATP provides energy for the cocking of the myosin head and the subsequent cross-bridge cycle, and is also required to detach the myosin head from the actin filament to repeat the process.

[1.25 marks] Calcium ions: explains release from sarcoplasmic reticulum, binding to troponin, and moving tropomyosin to expose myosin-binding sites on actin. [1.25 marks] ATP: explains ATP binding to myosin, hydrolysis providing energy to cock the myosin head, and/or ATP binding to detach the cross-bridge.

During a soccer kick involving knee extension, the quadriceps act as the agonist (primary mover) and contract to extend the knee. Simultaneously, an inhibitory neural signal is sent to the hamstrings, which act as the antagonist. This signal prevents the hamstrings from contracting, allowing them to relax and stretch. This reciprocal inhibition prevents opposing muscle resistance, ensuring a smooth and powerful extension of the leg.

Award [0.5] for defining reciprocal inhibition (reflex relaxation of antagonist during agonist contraction).
Award [0.5] for identifying the quadriceps as the agonist in knee extension.
Award [0.5] for identifying the hamstrings as the antagonist in knee extension.
Award [1.0] for explaining how the neural inhibition of the antagonist prevents resistance and allows a smooth/efficient movement.

During prolonged sub-maximal exercise in a warm environment, sweating occurs to aid thermoregulation, which reduces blood plasma volume. Additionally, blood is redirected to the skin (cutaneous vasodilation) to dissipate heat. This leads to reduced venous return and a decrease in end-diastolic volume, which causes stroke volume (SV) to decline. To maintain a constant cardiac output \(Q = \text{HR} \times \text{SV}\), the heart rate (HR) must progressively increase.

Award [0.5] for identifying that sweating reduces blood plasma volume.
Award [0.5] for explaining that blood is redirected to the skin for thermoregulation, reducing venous return.
Award [0.5] for stating that the reduced venous return leads to a decrease in stroke volume (SV).
Award [1.0] for explaining that heart rate (HR) must increase to maintain a constant cardiac output \(Q = \text{HR} \times \text{SV}\).

Consuming high GI carbohydrates 30 minutes before a marathon causes a rapid spike in blood glucose levels, prompting a large release of insulin. This can lead to reactive (rebound) hypoglycemia at the start of the race as glucose is rapidly cleared from the blood, and also inhibits fat oxidation. Conversely, low GI carbohydrates are digested and absorbed slowly, providing a steady, prolonged delivery of glucose without a massive insulin surge. This helps maintain stable energy levels, promotes fat oxidation, and spares muscle glycogen reserves during the endurance event.

Award [1.0] for the effect of high GI carbohydrates: rapid blood glucose rise, high insulin surge, risk of reactive hypoglycemia, or inhibited lipid oxidation.
Award [1.0] for the effect of low GI carbohydrates: slow/gradual release of glucose, avoidance of insulin spike, promoting stable energy levels, or sparing glycogen.
Award [0.5] for clear comparative language distinguishing the two types of GI carbohydrate impacts on exercise performance.

Transfer of learning describes how previous experience influences the acquisition of a new skill.
1. Positive transfer: Occurs when a previously learned skill aids the learning of a new skill because of similar movement patterns or cognitive demands (e.g., a basketball player learning a netball pass).
2. Negative transfer: Occurs when a previously learned skill interferes with the acquisition of a new skill, often due to conflicting movement requirements (e.g., the wrist snap in badminton hindering the firm-wrist technique required in tennis).
3. Zero transfer: Occurs when there is no similarity or relationship between the skills, meaning the previous skill has absolutely no effect on learning the new one (e.g., playing chess has zero transfer to learning how to kick a soccer ball).

Award [0.5] for defining positive transfer and providing a suitable example.
Award [0.5] for defining negative transfer and providing a suitable example.
Award [0.5] for defining zero transfer.
Award [1.0] for explaining the underlying reasons for the differences (e.g., similarity of motor programs, cognitive elements, or stimulus-response requirements for positive/negative vs complete independence for zero transfer).

Acetylcholine (ACh) is a neurotransmitter released from the motor neuron into the synaptic cleft at the neuromuscular junction. It binds to receptors on the sarcolemma (muscle cell membrane), causing depolarization and generating an action potential. This action potential propagates down the T-tubules into the muscle fiber, which stimulates the sarcoplasmic reticulum to release stored calcium ions. Once released into the sarcoplasm, calcium ions bind directly to the regulatory protein troponin. This binding causes a conformational change in tropomyosin, shifting it away from the active binding sites on the actin filament. This exposes the myosin-binding sites on actin, allowing the myosin heads to bind, form cross-bridges, and perform the power stroke.

Award [1] for stating ACh is released at the neuromuscular junction and binds to sarcolemma receptors. Award [1] for explaining that ACh binding generates an action potential that travels down the T-tubules. Award [1] for stating that the action potential triggers the release of calcium ions from the sarcoplasmic reticulum. Award [1] for describing how calcium binds to troponin, causing a conformational change in tropomyosin. Award [1] for explaining that the movement of tropomyosin exposes actin-myosin binding sites, allowing cross-bridge formation.

Carbohydrate loading is a nutritional technique involving a high carbohydrate intake combined with an exercise taper in the days leading up to an endurance event. The primary benefit is the supercompensation of muscle glycogen stores above normal resting levels, ensuring optimal fuel availability. This delays the onset of fatigue and prevents 'hitting the wall' by maintaining blood glucose levels during prolonged exercise. However, a major drawback is water retention, as every gram of glycogen stored is accompanied by approximately 3 grams of water, which can make the runner feel heavy or stiff. Additionally, consuming massive amounts of carbohydrates can lead to gastrointestinal distress, bloating, or digestive discomfort if not practiced beforehand.

Award [1] for defining carbohydrate loading (combining high CHO intake with an exercise taper). Award [2 max] for benefits: maximises glycogen stores [1], delays fatigue/prolongs performance [1]. Award [2 max] for drawbacks: water retention/weight gain [1], gastrointestinal discomfort/bloating [1].

During prolonged exercise in a warm environment, the body increases sweat rate to facilitate evaporative cooling. This progressive loss of fluid leads to a reduction in blood plasma volume. Consequently, there is a decrease in venous return to the heart and a lower end-diastolic volume. This reduction in ventricular filling causes stroke volume to decrease. To maintain a constant cardiac output (Cardiac Output = Heart Rate x Stroke Volume), the heart rate must progressively increase to compensate for the falling stroke volume.

Award [1] for stating that sweating to dissipate heat leads to fluid loss. Award [1] for identifying a reduction in blood plasma volume. Award [1] for explaining that decreased plasma volume reduces venous return to the heart. Award [1] for stating that reduced venous return leads to a decrease in stroke volume. Award [1] for explaining that heart rate must increase to maintain cardiac output.

An athlete in the cognitive stage of learning is focused on understanding the basic movement patterns and relies heavily on external (extrinsic) feedback from a coach or video because they lack the sensory awareness to detect errors themselves. This feedback needs to be simple, prescriptive, and immediate. They benefit most from Knowledge of Results (KR) to understand the outcome of their actions. Conversely, an athlete in the autonomous stage has well-established motor programs and relies primarily on internal (intrinsic) feedback, such as proprioception and kinesthetic feel, allowing them to self-correct during or immediately after the movement. External feedback for autonomous learners is highly detailed, descriptive (Knowledge of Performance, KP), and can be delayed to encourage self-analysis.

Award [1] for stating cognitive learners rely on external/extrinsic feedback whereas autonomous learners rely on internal/intrinsic feedback. Award [1] for stating cognitive learners require simple/immediate feedback. Award [1] for explaining that autonomous learners can self-detect and correct errors. Award [1] for stating cognitive learners focus on Knowledge of Results (KR) to understand success. Award [1] for stating autonomous learners utilize detailed Knowledge of Performance (KP) to refine technique.