Strongman Physiology - Episode 9: Muscle Glycogen and Energy Availability

1. Why glycogen matters so much in Strongman

Glycogen is the storage form of glucose in liver and muscle. For a strength athlete, muscle glycogen is particularly important because it supplies glucose rapidly for glycolysis during exercise. In Strongman, where a competition day can combine deadlifts, carries, loading events, medleys and efforts of different durations, glycogen availability becomes part of the performance equation.

This does not mean every heavy repetition is fueled exclusively by glycogen. Stored ATP, phosphocreatine, glycolysis and oxidative metabolism contribute at the same time. Glycogen matters especially because it can provide rapid substrate when intensity and duration rise and when rest intervals are too short for complete recovery.

2. Where is glycogen stored?

Glycogen is stored mainly in skeletal muscle and the liver. Liver glycogen helps maintain blood glucose, whereas muscle glycogen is used primarily within the muscle fiber where it is stored. This distinction matters: glycogen stored in one working muscle cannot simply be exported to fuel another muscle.

In a Strongman athlete, local glycogen distribution can matter depending on the events. A high-volume lower-body day may deplete important local stores, and another demanding session may begin before those stores are fully restored.

3. Glycogen and exercise intensity

As exercise intensity increases, carbohydrate use and glycolytic contribution become more important. Short, intense efforts rely heavily on rapid energy systems, and glycogen provides substrate for ATP regeneration through glycolysis.

That is why a 30-60 second medley can create a very different metabolic demand from one maximal deadlift, even though both are perceived as extremely hard. The medley requires repeated energy delivery, while the single lift depends more heavily on ATP, phosphocreatine, neural output and coordination.

4. Glycolysis: how glycogen becomes rapid energy

Glycolysis breaks down glucose or glycogen-derived glucose and produces ATP rapidly. At high intensity, this pathway can support work when energy demand exceeds the rate at which oxidative metabolism can provide ATP.

The end product of glycolysis is pyruvate, which can enter oxidative metabolism or be converted to lactate. Lactate is not merely waste. It participates in carbon transport and recycling and can later serve as fuel in other tissues.

5. Muscle glycogen and repeated effort

In Strongman, the challenge is rarely a single isolated effort. The athlete has to repeat hard efforts with incomplete recovery. As glycogen falls, the ability to sustain repeated high-intensity work can be affected.

This becomes especially visible in high-set training, event sessions and competitions containing multiple events. Fatigue is an interaction between the nervous system, energy substrates, metabolite accumulation, contractile changes and central perception of effort.

6. What happens when glycogen stores fall?

As stores decline, sustainable work intensity can decrease and perceived effort can rise. There is no universal percentage at which performance suddenly stops. The effect depends on exercise type, duration, muscle groups involved, training status and starting glycogen.

For a Strongman, this means that an apparently ordinary training day can become much harder when it follows a high-volume session, inadequate fueling or an aggressive diet phase.

7. Carbohydrates enter the story

Dietary carbohydrates are one of the main sources for glycogen restoration. After digestion, glucose and other available carbohydrates enter circulation, while insulin and insulin-independent transport pathways contribute to glucose uptake by muscle.

For an athlete training frequently, total carbohydrate intake and its distribution around training become practical variables. There is no single formula that fits every Strongman.

8. The glycogen recovery window

After exercise, muscle is highly effective at taking up glucose and rebuilding glycogen. Glycogen-synthesis enzymes are active and insulin sensitivity is elevated.

The rate of restoration depends on how much glycogen was depleted, carbohydrate intake, time until the next session and the characteristics of the training. When many hours remain before the next workout, the pressure to use a very narrow recovery window is lower.

9. Why training frequency matters

If a Strongman has one demanding session per day and a full recovery day, there is substantial time for glycogen restoration. When an athlete performs two sessions, events and conditioning close together, rapid recovery becomes more relevant.

During competitions, two demanding events on the same day may consume local stores faster than they can be restored. Fueling strategy has to match the actual event structure rather than a universal rule.

10. Energy availability: the concept that connects everything

Energy availability describes the energy remaining for physiological functions after exercise energy expenditure is subtracted from food intake, usually expressed relative to fat-free mass. It matters in sport because performance depends not only on calories consumed but also on how much energy remains for maintenance and adaptation.

Prolonged low energy availability can affect endocrine function, bone health, immunity, mood, recovery and training capacity. The problem is not that the body suddenly cannot burn fat, but that resources available for the whole system become insufficient.

11. Low Energy Availability in the strength athlete

Low energy availability can occur in strength athletes, not only in endurance or weight-class sports. It is particularly relevant during dieting, competition preparation, high training volume or periods when appetite fails to keep pace with energy expenditure.

Signs may be nonspecific: persistent performance decline, poor recovery, disturbed sleep, mood changes, feeling unusually cold, reduced libido and endocrine changes. These signs do not diagnose the condition by themselves, but they deserve context.

12. Why low energy availability can affect hormones

When energy is scarce, the body changes how it prioritizes functions. Metabolic and neuroendocrine signals shift, and reproductive and anabolic processes can be downregulated. In men, low energy availability may contribute to lower testosterone, while both sexes can experience changes in reproductive and metabolic axes.

This links directly with the previous episodes on testosterone, GH and insulin: hormones do not operate in a vacuum, but in relation to available resources.

13. Glycogen and the nervous system

Strongman performance is not purely muscular. The brain regulates motor recruitment, perception of effort, coordination and motivation. Changes in energy availability and systemic glucose regulation can influence central function even when local muscle glycogen remains available.

This is one reason inadequate fueling can make an athlete feel “empty” or flat before a simple blood-glucose measurement demonstrates a problem.

14. Glycogen and deadlift events

A maximal deadlift is dominated by rapid force production and the phosphagen system. However, the training session may contain multiple sets, warm-ups, back-off work and assistance exercises. In that context, glycogen contribution becomes much greater than a single repetition might suggest.

15. Glycogen and carries

Farmer's walks, yoke carries and other moving events require force to be maintained over time and distance. As duration increases, glycolysis and oxidative metabolism become increasingly important.

That is why an athlete entering a session with poorly restored glycogen may notice the difference more during repeated work than during the first single effort.

16. Glycogen and loading events

Stone loading, sandbag work and awkward-object events combine strength with repeated effort and mechanically demanding positions. The work intervals may be short but sufficient to require meaningful glycolytic support, especially across repeated lifts.

The large amount of muscle involved also makes these events energetically expensive when repeated.

17. Why medleys are excellent metabolic tests

A medley changes the task demand almost instantly. The athlete moves from one object to another with minimal rest and little opportunity to fully restore phosphocreatine between segments. Glycolysis therefore becomes crucial, while metabolite accumulation contributes to performance limitation.

A good Strongman athlete does not only produce force. He or she has to carry that force through several consecutive tasks.

18. Glycogen, lactate and the feeling of “burn”

The familiar burning sensation during intense effort reflects local metabolic changes involving hydrogen ions, pH shifts and other by-products. Lactate is part of this system, but it is not a complete explanation for soreness or fatigue.

19. Glycogen restoration: what really matters

The main variables are sufficient carbohydrate intake, the time available between sessions and the amount of glycogen depleted. Protein is important for muscle repair and adaptation, but it does not replace carbohydrate when rapid glycogen restoration is the main goal.

If the next session is more than 24 hours away, an extreme recovery strategy is rarely necessary. If the next demanding session is very close, restoration speed becomes more important.

20. Insulin and glycogen restoration

Insulin promotes glucose uptake and activation of glycogen synthase. After exercise, increased insulin sensitivity allows muscle to respond efficiently to ingested carbohydrate.

This is one reason the previous insulin episode fits directly with glycogen physiology: insulin is not the enemy, but part of the normal system that restores energy reserves.

21. Glycogen and hydration

Glycogen is stored with associated water in muscle. When stores are rebuilt, associated water content also rises. Rapid weight changes after increasing carbohydrate intake therefore do not automatically represent fat gain.

For Strongman athletes, hydration and electrolytes separately influence neuromuscular function, plasma volume and exercise tolerance.

22. What happens during a fat-loss phase?

When calorie intake falls, carbohydrate intake often falls as well, depending on the diet structure. At the same time, training may remain hard. If the restriction is severe, glycogen can become harder to maintain and total energy availability may become problematic.

In intelligent competition preparation, the goal is not to eliminate carbohydrates, but to find the smallest effective deficit that meets the desired goal without destroying performance and recovery.

23. Refeeds, carb cycling and physiological reality

Higher-carbohydrate days can be useful in selected diet strategies to support training and adherence. Neither refeeds nor carb cycling need to be treated as metabolic magic.

The body responds to total energy intake, training load, glycogen and the broader hormonal environment. A good structure solves a practical problem without creating another one.

24. Why zero-carbohydrate approaches are rarely a universal Strongman strategy

Very low carbohydrate intake can fit selected medical or dietary situations, but Strongman is not a sport where glycogen availability can be ignored without possible costs.

When training includes multiple events, high volume and repeated high-intensity work, carbohydrate is an important performance tool. It is not the enemy of insulin or body composition.

25. Glycogen supercompensation

After partial depletion followed by adequate carbohydrate intake, muscle can store glycogen above its starting level. This supercompensation phenomenon is well established, although its magnitude depends on training, diet and starting stores.

26. Glycogen and muscle size

Glycogen contributes to cell volume and can support training performance. It is not equivalent to contractile muscle tissue. A rapid increase in body weight after increasing carbohydrate intake can partly reflect glycogen restoration and associated water.

27. Energy availability and bone health

Chronically insufficient energy can affect bone remodeling and hormonal regulation. For Strongman athletes, this matters because the skeleton must tolerate very high repeated loads.

Performance cannot be separated from structure. A very strong athlete who is chronically under-fueled may compromise the infrastructure on which that strength depends.

28. Energy availability and immunity

The immune system requires resources. Long periods of physiological stress and insufficient energy can be associated with altered immune function and poorer tolerance of heavy training.

29. Sleep, glycogen and appetite

Poor sleep can alter appetite regulation, glucose control and perceived effort. For an athlete trying to keep up with a large training load, sleep loss and insufficient intake can reinforce each other.

30. What does a well-fueled Strongman look like?

There is no single model. In general, a well-fueled athlete has enough total energy for the current training phase, adequate protein, carbohydrate appropriate to workload, sufficient fat and hydration matched to sweat losses and the environment.

31. Glycogen and pre-competition preparation

Before competition, the goal is not simply to eat as much as possible, but to start with good energy stores and a comfortable gastrointestinal tract. A moderate, planned increase in carbohydrate can be useful when timing and tolerance allow.

32. What happens between events?

Between events, the body has to restore ATP, phosphocreatine, local glycogen and fluid balance. The speed of recovery depends on the intensity of the preceding event and the interval before the next one.

Competition nutrition should therefore be part of strategy. A food or drink that is perfect in theory may be useless if it causes gastrointestinal distress in the middle of competition.

33. Electrolytes and carbohydrate in context

In hot conditions with substantial sweating, water and electrolytes become as important as energy. Carbohydrate and sodium can be combined in selected strategies, but needs depend on sweat rate, temperature and exercise duration.

34. Why body weight can change quickly

Glycogen, water, gut contents and sodium can all produce meaningful short-term weight changes. A Strongman should not interpret every kilogram on the scale as a change in body fat or contractile muscle.

35. Metabolic flexibility in the strength athlete

A trained body can shift efficiently between carbohydrate and fat use depending on fed state, exercise intensity and duration. Glycogen is valuable because it can be mobilized rapidly when demand is high.

36. Why you do not need to chase fat oxidation all the time

Fat oxidation is relevant to energy metabolism, but good performance does not require maximizing fat burning at every moment. In high-intensity events, carbohydrate has important advantages as a rapid fuel.

37. Glycogen and training adaptation

Carbohydrate availability can influence how much high-quality work an athlete can perform. In Strongman, where many qualities are built through repeated exposure to heavy tasks, the ability to execute high-quality sessions consistently is critical.

38. When should carbohydrate intake change?

During high-volume blocks, carbohydrate intake can be increased to support workload. On easier or rest days, intake may be adjusted if total energy needs fall. This is a planning tool, not a hormonal rule.

39. Glycogen and conditioning

Intervals, sled work and circuits can generate meaningful glycogen use. When added to an already hard training week, the total metabolic cost can be larger than a single session suggests.

40. When conditioning conflicts with strength

The issue is not that athletes perform conditioning. The issue arises when its volume and timing reduce the quality of strength sessions or recovery. Glycogen availability is one of the links between those two worlds.

41. Glycogen and overreaching

A hard training block can temporarily reduce energy reserves. Planned overreaching must be distinguished from a situation where an athlete remains under-fueled for weeks and cannot recover.

42. Low Energy Availability is not the same as a “good diet”

A calorie deficit can be controlled and temporary. Low energy availability becomes a problem when the energy left for normal physiology is insufficient. The distinction depends on magnitude, duration and sporting context.

43. What signs deserve attention?

Declining performance, poor recovery, disrupted sleep, irritability, persistent fatigue, recurrent injury or hormonal changes can justify reviewing energy intake and training load.

44. What should not be done

It is not useful to use one indicator such as body weight, blood glucose or hunger alone to decide whether an athlete is adequately fueled. Sports physiology is multidimensional.

45. Glycogen and competition strategy

A good strategy begins with the meals in the days before competition, continues with breakfast and pre-event intake, and adapts between events. It should not be invented on competition day.

46. Training with lower glycogen: is it always bad?

No. There are contexts in which athletes manipulate carbohydrate availability to target specific metabolic adaptations, but that approach only makes sense when the goal and cost are clear. For primary strength and event preparation, high-quality training remains the priority.

47. Glycogen and psychological recovery

Insufficient fueling can increase perceived exhaustion and make training feel disproportionately difficult. Sometimes what is labeled a “discipline problem” is simply a mismatch between training cost and physiological resources.

48. The bigger picture

Muscle glycogen is a local reserve, but a Strongman's energy story is systemic. Pancreas, liver, adipose tissue, muscle, brain and endocrine systems work together to maintain fuel availability.

49. The practical rule

Food intake should be sufficient for the real demands of the training phase. Carbohydrate should be used as a tool for performance and glycogen restoration, not treated as a metabolic enemy. Energy deficits should be controlled when needed and avoided when they compromise adaptation.

50. Conclusion: the fuel you cannot see, but can feel

Muscle glycogen may not look as dramatic as a deadlift record, but when it is chronically poorly restored, repeated high-quality work can suffer. Energy availability goes even deeper: it determines how much the body can invest simultaneously in training, recovery, hormones, bone, immunity and adaptation.

For Strongman, the lesson is not to chase maximum carbohydrate or minimum carbohydrate. It is to match fuel to demand. A strong athlete needs not only the capacity to produce force, but also the resources required to produce it again tomorrow.

Selected bibliography

1. Burke LM, Hawley JA, Wong SHS, Jeukendrup AE. Carbohydrates for training and competition. Journal of Sports Sciences. 2011;29 Suppl 1:S17-S27.

2. Ivy JL. Muscle glycogen synthesis before and after exercise. Sports Medicine. 1991;11:6-19.

3. Jentjens R, Jeukendrup AE. Determinants of post-exercise glycogen synthesis during short-term recovery. Sports Medicine. 2000.

4. Hawley JA, Leckey JJ. Carbohydrate dependence during prolonged strenuous exercise. Sports Medicine literature.

5. Mountjoy M, Sundgot-Borgen J, Burke L, et al. IOC consensus statement on Relative Energy Deficiency in Sport (REDs). British Journal of Sports Medicine. 2023.

6. Thomas DT, Erdman KA, Burke LM. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance.

7. Sylow L, Kleinert M, Richter EA, Jensen TE. Exercise-stimulated glucose uptake and its regulation. Nature Reviews Endocrinology. 2017.

8. IOC and sports-nutrition consensus literature on carbohydrate availability, recovery and training adaptation.

Editorial note: this article is educational and does not replace individualized medical or nutritional evaluation. Dieting, weight-loss and energy-availability strategies should be adapted to the athlete's sporting context and health status.