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Stroke volume increases during incremental exercise in an untrained individual up to approximately 40-60% of \(VO_2\text{ max}\), after which it plateaus. Further increases in cardiac output beyond this intensity are achieved primarily through increases in heart rate.

Award 1 mark for identifying the correct answer (B). Reject other options as they describe linear increases (typical of cardiac output/heart rate) or constant stroke volume (incorrect physiological behavior).

Immediately post-exercise, high glycemic index (GI) carbohydrates are preferred because they cause a rapid increase in blood glucose and insulin levels, which maximizes the rate of muscle glycogen resynthesis.

Award 1 mark for selecting B. Reject other options because low GI carbohydrates (A) release glucose too slowly for rapid immediate replenishment, and avoiding carbohydrates (C, D) does not support glycogen resynthesis.

During the downward phase of a squat, the knee flexes. This movement is controlled against gravity by the eccentric contraction of the knee extensors (the quadriceps muscle group).

Award 1 mark for selecting C. Reject A and D because concentric contractions occur during the upward phase. Reject B because the hamstrings are not the primary muscle group controlling knee flexion against gravity in a squat.

According to Newton's Third Law (Action-Reaction), every action has an equal and opposite reaction. If the sprinter exerts a force of \(800\text{ N}\) backwards and downwards on the block, the block exerts an equal force of \(800\text{ N}\) in the opposite direction (forwards and upwards) on the sprinter.

Award 1 mark for selecting A. Reject B because reaction forces must be equal in magnitude. Reject C because while true, it does not describe the reaction force itself. Reject D because it states the directions are the same as the action force.

A penalty kick in soccer is classified as a closed skill because the environment is stable and predictable (the ball is stationary, opponents cannot interfere). It is a discrete skill because it has a distinct, well-defined beginning (the run-up) and end (the kick).

Award 1 mark for selecting D. Reject other options because open skills involve unstable environments and continuous/serial skills represent ongoing or linked series of movements.

In Fitts and Posner's model of learning, the autonomous stage is characterized by movements that are highly consistent, require minimal conscious control, and allow the athlete to focus on tactics or self-correction.

Award 1 mark for selecting C. Reject A (cognitive) as it is characterized by high error rates and deliberate thought. Reject B (associative) as movements are still being refined and require more conscious effort than the autonomous stage.

Progressive Muscle Relaxation (PMR) is a somatic relaxation technique that involves systematically tensing and relaxing major muscle groups to reduce physical tension associated with stress or anxiety.

Award 1 mark for selecting B. Reject A, C, and D as they are cognitive or different physiological relaxation techniques that do not focus primarily on active muscular contraction-relaxation cycles.

Intrinsic motivation refers to engaging in an activity for its inherent satisfaction, enjoyment, and personal challenge rather than for external rewards or pressures.

Award 1 mark for selecting C. Reject A and B because they refer to forms of extrinsic motivation. Reject D because amotivation is a complete lack of intent to act.

During progressive exercise, stroke volume increases and then plateaus at approximately 40% to 60% of VO2 max. The primary physiological reason for this plateau is the shortening of the diastolic phase of the cardiac cycle due to elevated heart rates. This significantly reduces the time available for ventricular filling (diastolic filling time), limiting further increases in stroke volume.

Award 1 mark for identifying that reduced ventricular filling time at high heart rates is the primary cause of the plateau. Reject other options as they represent physiological processes that either do not limit stroke volume in this manner or are incorrect.

A low glycemic index (GI) food consumed 3 hours pre-exercise allows for a slow, sustained release of glucose into the bloodstream, avoiding sudden insulin spikes. Conversely, high GI foods are rapidly digested and absorbed, making them ideal during the final stages of exercise to provide immediate carbohydrate energy to the working muscles.

Award 1 mark for identifying that Low GI is best before the race and High GI is best during the race.

The autonomous stage is characterized by performing the movement almost automatically, with minimal conscious attention directed to the motor mechanics. This allows the performer to focus their attention on external environmental factors (such as the opponent) and to utilize intrinsic feedback to detect and correct minor errors.

Award 1 mark for identifying the Autonomous stage. Reject other options as they represent stages where more conscious cognitive control is required.

During the downward phase of a squat, gravity is flexing the knees. To control the speed and depth of the descent, the quadriceps femoris (the knee extensors) must lengthen under tension. This is an eccentric muscle contraction.

Award 1 mark for identifying that the muscle action is an eccentric contraction while lengthening.

Newton's Third Law of Motion states that for every action, there is an equal and opposite reaction. Therefore, if the sprinter exerts a force of 800 N backward against the starting blocks, the blocks exert an equal and opposite reaction force of 800 N forward on the sprinter.

Award 1 mark for identifying the correct force magnitude (800 N) and direction (forward).

External imagery involves the athlete visualizing themselves from an outside perspective, similar to watching a video of themselves or from a spectator's viewpoint. Internal imagery, in contrast, would be from the athlete's own first-person perspective.

Award 1 mark for selecting the correct type of imagery (External).

Ectomorphs are characterized by high linearity, thin limbs, narrow shoulders and hips, and minimal muscle and fat accumulation. This body shape is highly suited for endurance running as it provides a high surface area to body mass ratio, facilitating heat dissipation.

Award 1 mark for identifying the correct somatotype category (Ectomorph).

Somatic anxiety refers to the physical perceptions of arousal, which include physiological symptoms like elevated heart rate, sweating, butterflies in the stomach, and increased muscle tension. Cognitive anxiety, in contrast, refers to the mental symptoms such as worry and negative thoughts.

Award 1 mark for identifying somatic anxiety. Reject cognitive anxiety as it represents mental processes rather than physical symptoms.

During prolonged submaximal exercise, sweating occurs to aid thermoregulation, which causes a progressive decrease in blood plasma volume. This reduction in blood volume reduces venous return and stroke volume. To maintain a constant cardiac output, the heart rate must increase progressively, a phenomenon known as cardiovascular drift.

Award [1] mark for identifying that heart rate increases and stroke volume decreases (Option B).

Consuming a low GI meal 3 to 4 hours before exercise provides a slow, sustained release of glucose into the bloodstream, avoiding rapid insulin spikes and early fatigue. Consuming high GI carbohydrates immediately post-exercise stimulates a rapid insulin response, which accelerates the replenishment of muscle glycogen stores.

Award [1] mark for identifying Low GI pre-race and High GI post-race (Option B).

During elbow flexion (the upward phase of a bicep curl), the biceps brachii is the agonist (prime mover) because it shortens to produce the movement (concentric contraction). The triceps brachii acts as the antagonist, which must relax or lengthen to allow the flexion to occur.

Award [1] mark for identifying the correct agonist/antagonist roles and contraction types (Option C).

A heel raise represents a second-class lever. The fulcrum (axis) is at the ball of the foot (metatarsal-phalangeal joints), the load (resistance) is the body weight acting down through the ankle joint, and the effort (force) is applied by the gastrocnemius muscle contracting via the Achilles tendon. The load lies between the fulcrum and the effort.

Award [1] mark for identifying the second-class lever with the load in the middle (Option B).

Intrinsic feedback is sensory information that is a natural consequence of performing a movement. It comes from internal sources, such as proprioception, tactile feel, and muscle tension, which allow the performer to evaluate the movement directly.

Award [1] mark for identifying intrinsic feedback (Option B).

A first-person perspective is characteristic of internal imagery. The feeling of muscular contraction represents the kinesthetic sensory modality, and the feeling of wind against the face represents the cutaneous (touch) sensory modality.

Award [1] mark for identifying the internal perspective with kinesthetic and cutaneous modalities (Option B).

Self-Determination Theory proposes that humans have three innate, basic psychological needs: autonomy (the need to feel in control of one's own life/actions), competence (the need to feel effective and master skills), and relatedness (the need to feel connected and have a sense of belonging with others).

Award [1] mark for identifying autonomy, competence, and relatedness (Option A).

McGrath's four-stage model of stress begins with an environmental demand (Stage 1), which is then subjectively perceived or appraised by the individual (Stage 2). This perception triggers a physiological and psychological stress response (Stage 3), which ultimately leads to a behavioral consequence or performance outcome (Stage 4).

Award [1] mark for identifying the correct chronological order of stages (Option B).

During sub-maximal steady-state exercise, both stroke volume and heart rate initially increase rapidly (within the first 2 to 3 minutes) to meet the increased oxygen demands of the active muscles. Once the oxygen supply meets the demand, both parameters plateau. This represents the cardiovascular response to steady-state exercise.

Award 1 mark for the correct option A. No marks for incorrect options.

In elbow flexion during a bicep curl, the biceps brachii is the agonist (prime mover) because it contracts concentrically to shorten and cause the movement. The triceps brachii is the antagonist because it relaxes and lengthens to allow the movement to occur.

Award 1 mark for the correct option B. No marks for incorrect options.

Catching a ball in a match is an open skill because the environment is dynamic and unpredictable; it is a gross skill because it involves large muscle groups and total body movement; and it is a discrete skill because it has a clear, distinct beginning and end.

Award 1 mark for the correct option C. No marks for incorrect options.

Carbohydrates are the main energy substrate for cellular metabolism (especially during exercise). Dietary fiber is indigestible plant material that helps maintain digestive health, prevents constipation, and supports bowel function.

Award 1 mark for the correct option A. No marks for incorrect options.

Newton's Second Law of Motion states that force is directly proportional to acceleration when mass is constant. Therefore, if the net force is doubled, the acceleration will also double.

Award 1 mark for the correct option C. No marks for incorrect options.

This is a performance goal because it focuses on achieving a specific personal standard of performance (a personal best time), independent of other competitors. Outcome goals focus on winning or beating others, and process goals focus on the specific behaviors or actions needed to perform well.

Award 1 mark for the correct option B. No marks for incorrect options.

**(a) (i) Percentage increase calculation:**
\( \text{Percentage change} = \frac{\text{Post-training} - \text{Pre-training}}{\text{Pre-training}} \times 100 \)
\( \text{Percentage change} = \frac{112 - 95}{95} \times 100 = \frac{17}{95} \times 100 \approx 17.89\% \) (accept 17.9% or 18%)

**(a) (ii) Change in submaximal heart rate:**
Submaximal heart rate decreased by 15 beats/min (from 140 beats/min to 125 beats/min).

**(b) Physiological adaptations explaining decreased heart rate:**
- **Cardiac hypertrophy:** Chronic endurance/HIIT training increases the size of the left ventricle (specifically chamber volume and myocardial wall thickness).
- **Increased Stroke Volume:** Due to cardiac hypertrophy and increased plasma volume, end-diastolic volume (preload) increases, resulting in a larger stroke volume per beat (Frank-Starling mechanism).
- **Autonomic Nervous System alterations:** Post-training, there is an increase in parasympathetic (vagal) activity and a reduction in sympathetic stimulation to the sinoatrial (SA) node.
- **Efficiency:** Because more blood is ejected per beat (increased stroke volume), the heart does not need to beat as frequently to meet the oxygen and nutrient demands of the body at rest and during submaximal workloads.

**(c) Relationship with Cardiac Output (Q) during submaximal exercise:**
- Cardiac output is the product of heart rate and stroke volume (\( Q = HR \times SV \)).
- At the same absolute submaximal workload (e.g., 150 Watts), the metabolic and oxygen demand of the working muscles remains the same pre- and post-training.
- Therefore, cardiac output (Q) remains relatively unchanged (or slightly decreases due to improved mechanical and mitochondrial efficiency).
- To maintain this stable cardiac output, the increase in stroke volume (SV) is balanced by a proportional decrease in submaximal heart rate (HR).

**(a) (i)**
- [1] Award 1 mark for showing correct working: \( \frac{112 - 95}{95} \times 100 \)
- [1] Award 1 mark for correct final answer: 17.89%, 17.9%, or 18%.

**(a) (ii)**
- [1] Award 1 mark for identifying the decrease of 15 beats/min (or stating it decreased from 140 to 125).

**(b)**
- [1] Award 1 mark for identifying cardiac hypertrophy / increased left ventricular volume.
- [1] Award 1 mark for stating that increased blood volume / plasma volume increases venous return and end-diastolic volume (preload).
- [1] Award 1 mark for explaining that increased stroke volume allows the heart to pump the same volume of blood with fewer beats.
- [1] Award 1 mark for explaining the role of increased parasympathetic (vagal) tone / decreased sympathetic activity.

**(c)**
- [1] Award 1 mark for defining cardiac output equation (\( Q = HR \times SV \)).
- [1] Award 1 mark for stating that oxygen demand at the same absolute submaximal workload remains the same, hence cardiac output remains relatively constant.
- [1] Award 1 mark for explaining that because SV has increased, the heart does not need to beat as fast (HR decreases).
- [1] Award 1 mark for a clear concluding synthesis showing the compensatory relationship between SV and HR to maintain steady-state Q.

**(a) (i) Relationship:**
As the carbohydrate concentration of the beverage increases, the gastric emptying rate decreases (an inverse relationship).

**(a) (ii) Calculation:**
Difference = \( 6.8 \text{ mmol/L} - 4.3 \text{ mmol/L} = 2.5 \text{ mmol/L} \)

**(b) Effect on GI discomfort:**
- Increasing carbohydrate concentration increases GI discomfort.
- Ingesting water (0%) or 6% CHO results in very low discomfort (1.1 and 1.8 respectively).
- There is a substantial/sharp increase in subjective GI discomfort when the carbohydrate concentration reaches 12% (rising to 5.2).

**(c) Physiological mechanisms for slower emptying and discomfort:**
- **Osmolarity:** A 12% carbohydrate solution has high osmolarity (it is hypertonic relative to body fluids).
- **Gastric Emptying Inhibition:** Osmoreceptors in the small intestine detect the high solute concentration and signal the stomach (via negative feedback / enterogastric reflex) to slow gastric emptying to prevent overwhelming the digestive tract.
- **Osmotic Water Shift:** The hypertonic fluid in the stomach and upper small intestine draws water from the vascular system into the intestinal lumen via osmosis to dilute the concentrated chyme.
- **Discomfort:** This sudden accumulation of fluid in the digestive tract causes gastrointestinal distension, bloating, cramping, and overall GI discomfort.

**(d) Recommendation of 6% solution over water:**
- **Exogenous Carbohydrate Delivery:** The 6% solution increases mean blood glucose significantly compared to water (5.6 mmol/L vs 4.3 mmol/L), which provides an external fuel source, sparing liver and muscle glycogen and delaying fatigue.
- **Hydration Efficiency:** Unlike the 12% solution, the 6% isotonic solution maintains a high gastric emptying rate (12.8 mL/min, which is close to water's 15.2 mL/min), ensuring rapid delivery of fluid and electrolytes.
- **Comfort:** The 6% solution causes negligible GI distress (score of 1.8), making it highly tolerable during strenuous activity compared to higher concentrations.

**(a) (i)**
- [1] Award 1 mark for stating the inverse relationship (higher carbohydrate concentration leads to slower/decreased gastric emptying rate).

**(a) (ii)**
- [1] Award 1 mark for correct calculation: 2.5 mmol/L (unit required).

**(b)**
- [1] Award 1 mark for stating that higher CHO concentration leads to higher GI discomfort.
- [1] Award 1 mark for using data to describe the non-linear trend (e.g., small increase between 0% and 6%, but a sharp/large increase at 12% / referencing the scores 1.1, 1.8, and 5.2).

**(c)**
- [1] Award 1 mark for identifying that the 12% solution is hypertonic / has high osmolarity.
- [1] Award 1 mark for explaining that intestinal/duodenal osmoreceptors detect this high solute concentration and slow gastric emptying to allow for digestion/dilution.
- [1] Award 1 mark for explaining that water is drawn into the gut lumen from the blood/extracellular fluid via osmosis.
- [1] Award 1 mark for linking this osmotic water shift to abdominal distension, bloating, or physical GI discomfort.

**(d)**
- [1] Award 1 mark for explaining that the 6% solution delivers energy/carbohydrates (maintaining higher blood glucose than water: 5.6 vs 4.3 mmol/L) to prevent hypoglycemia/glycogen depletion.
- [1] Award 1 mark for explaining that the 6% solution maintains a rapid rate of gastric emptying/fluid absorption (12.8 mL/min) compared to the hypertonic solution.
- [1] Award 1 mark for noting that it provides these benefits with minimal GI distress (1.8 score), keeping the athlete comfortable.

(a) Cardiovascular drift is defined as the gradual, progressive increase in heart rate and a corresponding decline in stroke volume during prolonged, constant-intensity submaximal exercise. (b) As exercise duration increases, metabolic heat production raises core body temperature. The body responds by sweating to facilitate evaporative cooling, which reduces blood plasma volume. Simultaneously, cutaneous vasodilation redirects blood flow to the skin to dissipate heat. Both the loss of fluid volume and the redistribution of blood reduce the volume of blood returning to the heart (venous return). According to Starling's law of the heart, a lower end-diastolic volume/venous return results in a reduced stroke volume. To maintain a constant cardiac output \(Q = \text{HR} \times \text{SV}\), the nervous system must increase the heart rate. (c) Runners can minimize cardiovascular drift by: 1. Implementing a structured hydration plan before and during the run to replace fluid lost to sweat, maintaining blood plasma volume. 2. Performing heat acclimatization training (exercising in the heat over 5 to 14 days), which stimulates plasma volume expansion and improves thermoregulatory efficiency.

(a) Award [1] for identifying a progressive/gradual increase in heart rate. Award [1] for identifying a corresponding/gradual decrease in stroke volume (or cardiac output remaining constant). (b) Award [1] per valid explanatory point up to [4 max]: - Exercise increases core temperature, causing sweating [1]. - Sweating causes a reduction in blood plasma volume [1]. - Cutaneous vasodilation (blood shunted to skin for cooling) occurs [1]. - Plasma loss and skin blood flow combined reduce venous return to the heart [1]. - Decreased venous return leads to a decrease in stroke volume (Starling's law) [1]. - Heart rate must increase to compensate and maintain cardiac output (\(Q = \text{HR} \times \text{SV}\)) [1]. (c) Award [1] per valid strategy up to [2 max]: - Maintaining hydration / consuming water or electrolyte drinks [1]. - Undergoing heat acclimatization training [1]. - Using active cooling strategies (e.g., cold water dousing, ice vests) [1]. - Adjusting (reducing) exercise intensity in hot conditions [1].

(a) Redistribution of blood flow (vascular shunt mechanism):
- At rest, only about 15-20% of systemic blood flow is directed to skeletal muscle, while the majority goes to visceral organs (kidneys, liver, gut, etc.).
- During high-intensity exercise, up to 80-85% of cardiac output is redirected to the active skeletal muscles.
- This is achieved through the vasodilation of arterioles and opening of precapillary sphincters supplying the working muscles.
- Simultaneously, vasoconstriction occurs in the arterioles and precapillary sphincters supplying non-essential organs (e.g., kidneys, digestive tract).
- The vascular shunt ensures that oxygen delivery matches the elevated metabolic demands of the working muscle tissue.

(b) Regulation of heart rate by the Cardiovascular Control Centre (CCC):
- The CCC is located in the medulla oblongata of the brain.
- It receives sensory input from various peripheral receptors: proprioceptors (detect joint and muscle movement), chemoreceptors (detect drops in blood pH, increases in partial pressure of carbon dioxide \(P_{CO_2}\), and decreases in oxygen \(P_{O_2}\)), and baroreceptors (detect changes in blood pressure).
- At the onset of exercise, input from proprioceptors and chemoreceptors increases, stimulating the CCC.
- The CCC activates the sympathetic nervous system, which sends impulses along the cardiac accelerator nerve to the sinoatrial (SA) node.
- This sympathetic stimulation increases the rate of depolarization of the SA node, increasing heart rate.
- Simultaneously, parasympathetic nervous system influence (vagal tone) is decreased via the vagus nerve, lifting the inhibitory effect on the SA node.
- Hormonal regulation also plays a role, as the CCC stimulates the adrenal medulla to release adrenaline/noradrenaline into the bloodstream, further increasing heart rate.

(c) Discussion of cardiovascular adaptations (Trained vs. Sedentary at submaximal exercise):
- Long-term endurance training leads to cardiac hypertrophy, specifically an increase in the left ventricular cavity size (eccentric hypertrophy) and myocardial wall thickness.
- This structural adaptation allows for a larger end-diastolic volume (EDV) and a more powerful contraction, significantly increasing stroke volume (SV) both at rest and during exercise.
- Endurance training also increases total blood volume and plasma volume, improving venous return (preload) and further enhancing stroke volume via Starling's Law of the Heart.
- Since cardiac output (\(Q\)) is the product of heart rate and stroke volume (\(Q = HR \times SV\)), and the oxygen cost of a specific submaximal workload is similar for both individuals, the required submaximal cardiac output is approximately the same.
- Because the trained athlete has a significantly higher stroke volume, they can maintain the required submaximal cardiac output with a much lower submaximal heart rate (bradycardia) compared to the sedentary individual.
- The sedentary individual has a smaller left ventricle and lower stroke volume, meaning their heart must beat significantly faster (higher submaximal HR) to achieve the same cardiac output.
- Additionally, capillary density in the trained skeletal muscle is increased, enhancing oxygen diffusion capacity and increasing the arterio-venous oxygen difference (\(a-vO_2\) diff), which reduces the absolute blood flow requirement for a given oxygen uptake compared to a sedentary individual.

Part (a): [4 marks maximum]
- Award 1 mark for noting the resting state of blood flow distribution (majority to kidneys/digestive system/viscera; 15-20% to muscle).
- Award 1 mark for noting the exercise state of blood flow distribution (80-85% redirected to active skeletal muscles).
- Award 1 mark for explaining vasodilation of arterioles/opening of precapillary sphincters in active muscles.
- Award 1 mark for explaining vasoconstriction of arterioles/closing of precapillary sphincters in non-essential organs.

Part (b): [6 marks maximum]
- Award 1 mark for identifying the medulla oblongata as the location of the CCC.
- Award up to 2 marks for explaining receptor inputs (proprioceptors detect movement, chemoreceptors detect chemical/pH changes, baroreceptors detect pressure changes).
- Award 1 mark for explaining the role of the sympathetic nervous system (cardiac accelerator nerve) increasing SA node activity.
- Award 1 mark for explaining the withdrawal of parasympathetic nervous system activity (vagus nerve decreases inhibitory control).
- Award 1 mark for explaining the hormonal influence (adrenal release of adrenaline/noradrenaline).

Part (c): [10 marks maximum]
- Award 1 mark for defining cardiac hypertrophy (specifically left ventricular volume expansion).
- Award 1 mark for stating that trained athletes have a significantly higher stroke volume (SV) than sedentary individuals.
- Award 1 mark for explaining how increased blood volume/plasma volume increases venous return / EDV (Starling's Law).
- Award 1 mark for explaining that cardiac output (\(Q\)) is calculated as \(HR \times SV\).
- Award 1 mark for stating that submaximal cardiac output (\(Q\)) remains similar between both individuals for the same submaximal workload.
- Award 1 mark for explaining that because SV is higher in the athlete, the heart rate (HR) must be lower to achieve the same submaximal cardiac output (bradycardia).
- Award 1 mark for explaining that the sedentary individual has a lower SV and therefore must compensate with a higher submaximal HR.
- Award 1 mark for discussing capillarization (increased capillary-to-fiber ratio in trained individuals).
- Award 1 mark for discussing the arterio-venous oxygen difference (\(a-vO_2\) diff), which increases in trained individuals due to better oxygen extraction.
- Award 1 mark for a clear comparative summary/conclusion linking structural adaptations directly to functional submaximal performance differences.

(a) Osmolarity is a measure of the solute concentration of a solution, defined as the number of osmoles of solute particles per liter of solution. Isotonic sports drinks have an osmolarity similar to blood plasma (approx. 275-295 mOsm/L), containing comparable concentrations of dissolved sodium and carbohydrates. Hypotonic sports drinks have a lower osmolarity than blood plasma, containing lower concentrations of solutes to promote rapid water absorption. Hypertonic sports drinks have a higher osmolarity than blood plasma, containing highly concentrated solutes (usually >8% carbohydrate) to maximize energy delivery.

(b) (i) Isotonic solutions contain sodium and glucose. Sodium and glucose are co-transported across the intestinal mucosal membrane into the epithelial cells via active transport systems (SGLT1 transporters). This transport of solutes increases the concentration gradient, which in turn draws water rapidly from the intestinal lumen into the bloodstream via passive osmosis. Plain water lacks these solutes, resulting in slower passive absorption since there is no actively created osmotic gradient.
(ii) Consuming highly hypertonic solutions (e.g., >10% carbohydrate) increases the osmolarity of the chyme in the small intestine. This hyperosmotic environment draws water out of the systemic circulation/extracellular fluid and into the intestinal lumen via osmosis to dilute the high concentration of solutes. This fluid shift delays gastric emptying, dehydrates the body's tissues, and causes significant gastrointestinal distress, such as abdominal cramping, bloating, and diarrhea.

(c) Sodium is critical in post-exercise recovery because it maintains the osmotic pressure of extracellular fluid, helping to preserve the volume of rehydrated fluid. It stimulates the thirst mechanism in the hypothalamus, prompting the individual to continue drinking until fully rehydrated. Additionally, sodium reduces urine production (diuresis) by the kidneys, ensuring that ingested fluids are retained in the body rather than excreted. Finally, it replaces the essential electrolytes lost through sweating, restoring electrolyte homeostasis.

(d) In the 24 hours prior to a marathon, the runner should consume high-carbohydrate meals (around 10-12 g of carbohydrates per kg of body weight) consisting of high-glycemic-index foods (e.g., white pasta, rice, bread) to maximize muscle and liver glycogen stores. They should consume fluids regularly (mostly water or sports drinks) and monitor their urine color to ensure it is pale straw-colored, indicating euhydration. High-fiber foods should be limited to prevent gastrointestinal discomfort during the race. 3 to 4 hours before the race, a light, carbohydrate-rich, low-fat pre-event meal should be eaten. 2 to 4 hours before, the runner should drink 5 to 7 ml of fluid per kg of body weight to allow adequate time for excess fluid to be excreted before the start.

(a) Max 4 marks:
- [1] Award 1 mark for defining osmolarity as the measure of solute concentration / number of solute particles per liter of solution.
- [1] Award 1 mark for explaining that isotonic drinks have an osmolarity similar to blood plasma (~275-295 mOsm/L).
- [1] Award 1 mark for explaining that hypotonic drinks have a lower osmolarity than blood plasma.
- [1] Award 1 mark for explaining that hypertonic drinks have a higher osmolarity than blood plasma.

(b)(i) Max 3 marks:
- [1] Award 1 mark for identifying active co-transport of glucose and sodium via SGLT1 across the intestinal membrane.
- [1] Award 1 mark for stating that this active transport creates an osmotic gradient.
- [1] Award 1 mark for explaining that water is drawn rapidly into the blood via passive osmosis following this gradient.

(b)(ii) Max 3 marks:
- [1] Award 1 mark for explaining that hypertonic solutions create a high osmotic concentration in the intestinal lumen.
- [1] Award 1 mark for explaining that water is drawn from the extracellular fluid/blood into the intestine via osmosis.
- [1] Award 1 mark for identifying symptoms of gastrointestinal distress (e.g., cramping, bloating, diarrhea) and/or delayed rehydration.

(c) Max 4 marks:
- [1] Award 1 mark for stating sodium preserves extracellular fluid volume / maintains osmotic pressure.
- [1] Award 1 mark for stating sodium stimulates thirst, encouraging continued drinking.
- [1] Award 1 mark for stating sodium reduces urine output / diuresis by promoting renal water retention.
- [1] Award 1 mark for stating sodium restores electrolyte balance by replacing losses from sweat.

(d) Max 6 marks:
- [1] Award 1 mark for carbohydrate loading / high carbohydrate intake (10-12 g/kg body weight) to maximize glycogen stores.
- [1] Award 1 mark for regular sipping of fluids to achieve euhydration / monitoring urine color.
- [1] Award 1 mark for avoiding high-fiber / spicy foods to reduce risk of gastrointestinal issues.
- [1] Award 1 mark for avoiding alcohol / excessive caffeine (diuretics).
- [1] Award 1 mark for pre-event meal 3-4 hours prior (high carbohydrate, low fat, low protein).
- [1] Award 1 mark for pre-event hydration 2-4 hours prior (5-7 ml/kg body weight).

(a) Open skills are motor skills performed in a dynamic, unpredictable environment where the performer must continuously adapt their movements to external factors (e.g., passing in football). Closed skills are performed in a stable, predictable, and self-paced environment where the movement can be planned and executed consistently without external distraction. The tumbling routine is a closed skill because the gymnastics floor is static, the environment is predictable, and the execution is entirely self-paced by the gymnast.

(b) Working memory has a limited processing capacity (approx. 7 items) and duration (up to 30 seconds). Long-term memory has an unlimited capacity and duration. During the cognitive phase of learning, the gymnast relies heavily on working memory to consciously process verbal instructions and visual demonstrations. The gymnast must retrieve basic movement components or previously learned motor schemas (e.g., a simple handstand or a round-off) from long-term memory into working memory. In working memory, these pieces are combined and structured into a new movement plan, which places a very high cognitive load on the gymnast.

(c) Massed practice involves continuous work with minimal or no rest periods between repetitions. Distributed practice involves practice intervals interspersed with rest periods or alternative tasks, where rest time is equal to or greater than practice time. While both practice types aim to improve motor performance through repetition, they differ significantly in suitability. Massed practice is generally unsuitable for a highly complex and dangerous skill like a back handspring because physical and mental fatigue accumulate rapidly, increasing the risk of technical errors and severe injury. Distributed practice is highly suitable because the rest intervals allow physical recovery, reduction of fatigue, mental rehearsal of the motor program, and structured feedback from the coach, leading to safer and more effective skill acquisition.

(d) Whiting's information processing model describes how information is handled:
1. Input: The gymnast receives physical and environmental stimuli (e.g., body position in mid-air, rotation speed, sight of the landing mat).
2. Receptor Systems: Sensory organs (proprioceptors in muscles/joints, vestibular apparatus in the inner ear for balance, eyes) detect these stimuli.
3. Perceptual Mechanism: The brain filters these inputs via selective attention, discarding irrelevant noise and interpreting the important signals (e.g., realizing they are over-rotating).
4. Translatory Mechanism: The interpreted sensory state is compared with stored memory schemas. A decision is made regarding how to adjust the body (e.g., choosing to extend the hips to slow down rotation).
5. Effector Mechanism: The brain formulates and sends the required motor commands down the central nervous system to the target muscle groups.
6. Muscular System: The relevant muscles contract to adjust body segments in flight.
7. Output: The physical action / motor response is executed (e.g., the adjusted body shape in the air).
8. Feedback: Proprioceptive and visual feedback about the outcome of the adjustment is routed back to the perceptual mechanism to evaluate and fine-tune subsequent actions.

(a) Max 3 marks:
- [1] Award 1 mark for distinguishing open skills (unpredictable/externally paced environment).
- [1] Award 1 mark for distinguishing closed skills (predictable/self-paced environment).
- [1] Award 1 mark for classifying the tumbling routine as a closed skill with justification (stable mat, self-paced).

(b) Max 4 marks:
- [1] Award 1 mark for describing working memory as limited in capacity and duration, processing immediate cues.
- [1] Award 1 mark for describing long-term memory as unlimited, storing motor programs and schemas.
- [1] Award 1 mark for explaining that the gymnast retrieves existing sub-routines (e.g., handstand) from long-term memory into working memory.
- [1] Award 1 mark for explaining that working memory integrates these retrieved schemas with new feedback/instructions under a high cognitive load.

(c) Max 5 marks:
- [1] Award 1 mark for defining massed practice (continuous, minimal rest).
- [1] Award 1 mark for defining distributed practice (broken up by rest intervals).
- [1] Award 1 mark for stating a comparison (both use repetition to consolidate motor learning).
- [1] Award 1 mark for explaining why massed practice is unsuitable (fatigue, high injury risk for complex/dangerous gymnastics skills).
- [1] Award 1 mark for explaining why distributed practice is suitable (allows physical recovery, cognitive reset, integration of coach feedback, mental rehearsal).

(d) Max 8 marks (1 mark for each correctly applied component of Whiting's model in this context):
- [1] Input: gymnast receives environmental/body stimuli (e.g., height, rotation, orientation).
- [1] Receptor systems: sense organs (proprioceptors, vestibular, visual) detect the stimuli.
- [1] Perceptual mechanism: selective attention filters and interprets relevant sensory cues (e.g., over-rotation).
- [1] Translatory mechanism: compares situation with stored schema to decide on the correction (e.g., extend arms/hips).
- [1] Effector mechanism: motor system prepares the specific motor commands to be sent to the muscles.
- [1] Muscular system: motor nerves stimulate muscles to contract and adjust position.
- [1] Output: the actual motor adjustment made in flight.
- [1] Feedback loop: internal/external feedback feeds back to the system to evaluate the success of the adjustment.