CSCS Periodization & Energy Systems — Questions and Answers

Question 1: What is the definition of a 'mesocycle' in traditional periodization planning?

A single training session lasting 60-90 minutes
A weekly training block of 5-7 days
A medium-length training phase of 3-6 weeks focusing on a specific biomotor quality (Correct answer)
The entire competitive season from start to finish

Correct answer: A medium-length training phase of 3-6 weeks focusing on a specific biomotor quality

A mesocycle is a medium-term training phase (typically 3-6 weeks) with a specific training focus such as hypertrophy, strength, or power, nested within the larger macrocycle (annual plan) and composed of individual microcycles (weeks).

Periodization hierarchy: Macrocycle (one year or full competition season) contains Mesocycles (3-6 weeks with specific training goal emphasis) which contain Microcycles (typically 1 week, daily training arrangement). Each mesocycle has a specific biomotor quality emphasis and defined volume and intensity parameters. A typical annual plan for a team sport athlete: GPP mesocycle (anatomical adaptation and hypertrophy, 4-6 weeks) then SPP and Strength (4-6 weeks) then Power (3-4 weeks) then Competitive season maintenance (ongoing). Transition mesocycles of 1-2 weeks of reduced load are inserted between major mesocycles to allow recovery and supercompensation before the next training phase begins.

Question 2: What is the approximate time for phosphocreatine (PCr) to be 50% resynthesized after maximal-effort exercise?

5-10 seconds
30 seconds (Correct answer)
2-3 minutes
8-10 minutes

Correct answer: 30 seconds

PCr resynthesis follows an exponential curve: approximately 50% is restored within 30 seconds, 84% within 3 minutes, and near-complete restoration (97%) requires 8-10 minutes, directly informing rest interval prescription.

PCr resynthesis kinetics (Harris et al., 1976): 50% restored in approximately 30 seconds, 75% in approximately 90 seconds, 84% in approximately 3 minutes, and 97% in 8-10 minutes. PCr resynthesis is oxygen-dependent — the aerobic system powers the replenishment process. This is why aerobic fitness improves recovery between high-intensity efforts (better PCr resynthesis between sport plays or training sets). CSCS rest interval prescriptions are built on this data: strength and power training (short high-intensity sets) requires 3-5 or more minutes to allow 85% or greater PCr restoration; hypertrophy training (moderate intensity) uses 60-90 seconds of intentional incomplete recovery; endurance circuits use 30 seconds or less.

Question 3: The General Adaptation Syndrome (GAS) model proposes three stages of response to a training stressor. In the correct order, these are:

Exhaustion, Resistance, Alarm
Alarm, Exhaustion, Resistance
Alarm, Resistance, Exhaustion (Correct answer)
Resistance, Alarm, Exhaustion

Correct answer: Alarm, Resistance, Exhaustion

Selye's GAS model sequence: (1) Alarm reaction — initial response to new stressor causing temporary performance decrease; (2) Resistance — adaptation and supercompensation above baseline; (3) Exhaustion — if stressor exceeds adaptive capacity, performance declines chronically.

Selye's GAS (1950) provides the physiological basis for periodization design. Alarm reaction: novel stress disrupts homeostasis and performance temporarily decreases. Resistance stage: the body adapts and supercompensates — performance rises above the pre-stress baseline, which is the target outcome of each training block. Exhaustion stage: if stress is too great or too prolonged without adequate recovery, adaptive capacity is exceeded and performance declines chronically (overtraining syndrome). Periodization manages this continuum by varying training stress through progressive overload, incorporating planned deloads (prevents exhaustion phase), and timing peak performance (competition) to coincide with the supercompensation peak of the Resistance stage.

Question 4: What respiratory exchange ratio (RER) value indicates that carbohydrate is the exclusive fuel being oxidized?

RER = 0.70
RER = 0.85
RER = 1.00 (Correct answer)
RER = 1.10

Correct answer: RER = 1.00

RER equals VCO2 divided by VO2. Pure carbohydrate oxidation produces exactly one mole of CO2 for every mole of O2 consumed, giving an RER of 1.00. Pure fat oxidation gives 0.70-0.72 and mixed substrates give intermediate values.

Respiratory Exchange Ratio equations: Carbohydrate (glucose C6H12O6 plus 6O2 yields 6CO2 plus 6H2O) gives RER of 6 divided by 6 equals 1.00. Fat (palmitate C16H32O2 plus 23O2 yields 16CO2 plus 16H2O) gives RER of 16 divided by 23 equals 0.70. Protein RER is approximately 0.82. At rest (0.78-0.85): mixed substrate use. At moderate intensity: 0.85-0.90 with carbohydrate increasingly predominant. At VO2max and above: RER often exceeds 1.00 due to bicarbonate buffering of lactate releasing non-metabolic CO2. An RER above 1.10 at exhaustion is used as one criterion for confirming a true VO2max has been reached during maximal graded exercise testing.

Question 5: What is the key difference between an accumulation block and an intensification block in block periodization?

Accumulation uses high-intensity low-volume work; intensification uses high-volume low-intensity work
Accumulation uses high-volume lower-intensity training to build work capacity; intensification uses lower-volume higher-intensity training to convert work capacity to sport-specific performance (Correct answer)
Both blocks use identical volume and intensity with only exercise selection differing between them
Accumulation blocks are used exclusively for endurance athletes; intensification blocks are only for strength athletes

Correct answer: Accumulation uses high-volume lower-intensity training to build work capacity; intensification uses lower-volume higher-intensity training to convert work capacity to sport-specific performance

Block periodization (Issurin) sequences: Accumulation (high volume, 60-75% intensity, general preparation) then Intensification (reduced volume, 75-90% intensity, specific strength and power) then Realization (lowest volume, over 90% intensity, competition peaking).

Issurin's block periodization structure: (1) Accumulation block (3-6 weeks): high volume, lower intensity, develop aerobic base, hypertrophy, and general strength capacity; (2) Intensification block (3-4 weeks): reduced volume, higher intensity, develop maximal strength, speed-strength, and sport-specific power; (3) Transformation/Realization block (1-2 weeks): lowest volume, highest intensity, peak for competition through tapering. Advantages over traditional periodization include concentrated stimulus producing more specific adaptation, less concurrent training interference, and applicability to athletes with established training base. This approach requires high training experience to tolerate concentrated blocks and precise sequencing to avoid detraining between phases.

Question 6: Which of the following best describes the difference between VO2max and lactate threshold as predictors of endurance performance in trained athletes?

VO2max is always the better predictor because lactate threshold remains constant with training
Lactate threshold (as a percentage of VO2max) is generally a better predictor in trained athletes because it reflects the highest sustainable aerobic exercise intensity (Correct answer)
Both measures predict performance equally well regardless of athlete training status
VO2max directly measures lactate production, making lactate threshold measurement redundant

Correct answer: Lactate threshold (as a percentage of VO2max) is generally a better predictor in trained athletes because it reflects the highest sustainable aerobic exercise intensity

In trained athletes with similar VO2max values, lactate threshold expressed as a percentage of VO2max is a stronger predictor of endurance performance because it indicates the highest sustainable intensity before significant lactate accumulation occurs.

VO2max is a strong predictor in heterogeneous populations (untrained versus trained comparisons). In trained endurance athletes with similar VO2max values, lactate threshold (LT) or onset of blood lactate accumulation (OBLA at 4 mmol/L) becomes the primary performance discriminator because athletes differ in what fraction of VO2max they can sustain aerobically. A higher LT expressed as percent VO2max means greater aerobic contribution at race pace. Training raises LT without necessarily increasing VO2max. The combination of VO2max, LT percentage, and running economy (oxygen cost per unit speed) predicts endurance performance with high accuracy across competitive athlete groups.

CSCS Periodization & Energy Systems

What is the definition of a 'mesocycle' in traditional periodization planning?