Strongman Physiology - Episode 3: Breathing and Abdominal Pressure During Maximal Effort

Episodes 1 and 2 looked at the cardiovascular system and then the heart under load. Now we move into the mechanical center of maximal effort: breathing, the diaphragm, intra-abdominal pressure and intrathoracic pressure. For a Strongman, breathing is not only about oxygen. During a heavy lift it contributes to trunk stability, force transfer and, at the same time, changes the hemodynamic response.

This is why an effective breathing strategy cannot be reduced to the command 'hold your breath'. What matters is how much air you take in, where you expand the trunk, when you close the glottis, how long you maintain pressure and when you release it. In Strongman, these decisions change from event to event.

1. Resting breathing is not maximal-effort breathing

At rest, the respiratory system mainly manages gas exchange and acid-base balance. During a maximal effort, the mechanical demand changes abruptly. The athlete must stabilize the spine, control the trunk and transfer force between the ground, body and implement. Breathing becomes part of the strength strategy.

Bracing can be described as an intentional increase in trunk stiffness through coordinated activity of the diaphragm, abdominal and spinal muscles and control of the rib cage and pelvis. Valsalva is a specific respiratory maneuver that may appear within this strategy when the load approaches maximum.

2. The diaphragm: more than a breathing muscle

The diaphragm separates the thorax from the abdomen and is the main inspiratory muscle. During normal breathing, it contracts and descends, increasing thoracic volume. During bracing, however, it works within a wider mechanical system. Its movement interacts with the abdominal wall, pelvic floor and axial musculature to increase internal pressure and trunk stiffness.

This matters in Strongman because many events require the trunk to remain stable while the limbs produce force. Uncontrolled trunk motion can mean loss of position, lower mechanical efficiency and redistribution of load toward structures that should not become the weak link.

3. What is intra-abdominal pressure?

Intra-abdominal pressure, or IAP, is the pressure inside the abdominal cavity. It is relatively low at rest but can rise many times over during strength exercise. It depends on body position, load, range of motion, technique, abdominal contraction and respiratory strategy.

A systematic review of intra-abdominal and intrathoracic pressures during resistance exercise identified some of the highest reported values during squatting, above 200 mmHg in certain protocols. High values have also been reported during deadlifts and leg presses. These figures are experimental observations, not training targets.

4. IAP, ITP and arterial pressure are different variables

IAP is not intrathoracic pressure and neither is the same as arterial pressure. IAP is pressure inside the abdomen. ITP is pressure inside the thorax. Arterial pressure is the force exerted by blood on arterial walls. During a heavy lift, all three may change at the same time, but through different mechanisms.

The distinction matters. Increased abdominal pressure can contribute to trunk stiffness. Increased intrathoracic pressure can alter venous return and cardiac filling. At the same time, intense muscle contraction and sympathetic activation can drive arterial pressure sharply upward.

5. The Valsalva maneuver: what happens when you close the glottis?

Valsalva is forced expiration against a closed glottis. In the weight room, the version used during maximal lifting is usually very brief and occurs inside a broader bracing strategy. The literature shows that the maneuver raises IAP and ITP and that the magnitude of the response increases with exercise intensity.

It is useful to separate the medical term from the exact behavior of a lifter. A breath hold lasting a few seconds during one repetition is not identical in duration and context to the Valsalva protocol used in a clinical test. Still, the pressure mechanisms overlap and explain why breathing has real cardiovascular effects.

6. Why can bracing increase spinal stability?

The simple image of having 'a tight stomach' is not enough to explain the phenomenon. Trunk stability emerges from interaction among geometry, tissue tension, abdominal and spinal musculature, internal pressure and neural control. IAP can contribute to rigidity, but it is not the only mechanism.

That is why more pressure does not automatically mean more protection. During a few seconds of maximal effort the respiratory cost may be tolerable. During an event lasting 30–60 seconds, the same strategy maintained continuously can limit ventilation and become a performance problem.

7. What happens to venous return?

When intrathoracic pressure rises, the pressure gradients that normally help return blood to the heart change. During certain phases of a Valsalva maneuver, venous return falls and cardiac filling changes temporarily. When the maneuver is released, the cardiovascular system rapidly enters another hemodynamic phase.

This is one reason some athletes experience dizziness after a very heavy repetition. There is no single universal mechanism, but rapid pressure changes, vasodilation in active muscle and changes in venous return can all contribute.

8. Why can arterial pressure rise so dramatically?

During maximal contraction, active muscles compress local vessels. Sympathetic activation increases heart rate and contractility, and vascular resistance can rise. Add the intrathoracic pressure generated by bracing and Valsalva, and arterial pressure can reach very high values for brief periods.

Classic studies measured, under extreme protocols, mean values around 320/250 mmHg during leg press at 80–100% of maximum, with individual values even higher. These are not normal resting values and should never be treated as targets to reproduce. They demonstrate how different the cardiovascular response to maximal resistance exercise can be from a resting measurement.

9. Breathing and blood flow in working muscle

There is an interesting physiological paradox: during powerful contraction, muscle needs blood flow but can simultaneously compress its own vessels. During rhythmic exercise, vasodilation and the muscle pump support flow. During very strong near-isometric contractions, mechanical compression can be much greater.

Strongman combines these worlds. Farmer's Walk and Yoke Walk involve contraction, stabilization and locomotion. A maximal deadlift is dominated by strength and pressure. Repeated loading adds a metabolic component. The same respiratory strategy is therefore not optimal for every event.

10. Breathing in deadlift, squat and loading

In deadlifts and squats, the athlete needs a very rigid trunk during the critical phase of the repetition. Inhaling before the lift, expanding the trunk three-dimensionally and creating abdominal tension can improve stability. In loading events, the object must then be accelerated and controlled, making position maintenance under a moving load especially important.

In fast repeated efforts, repeatability becomes the problem. The athlete must rebuild pressure and trunk position without unnecessarily exhausting respiratory capacity. This is one of the differences between a maximal repetition and a volume event.

11. Farmer's Walk and Yoke Walk: pressure while moving

These events are almost a natural laboratory for bracing physiology. The athlete must stabilize the trunk while locomotion adds movement and balance demands. Pressure can no longer be treated as an isolated action performed once before a single repetition.

During a heavy Yoke Walk, every step changes the center of mass and the forces acting on the trunk. In a Farmer's Walk there is also a need to control lateral rotation. Respiratory strategy must therefore support stability without unnecessarily blocking ventilation.

12. Medleys: when breathing becomes a limiter

In a medley, the athlete cannot treat each event as an isolated repetition. After the first object, the next task begins. After a carry comes loading. After loading comes another movement. Carbon dioxide, ventilation and metabolic acidosis become increasingly relevant.

This is one of the major differences between strength and the ability to express strength repeatedly. An athlete may have enough absolute strength but, without enough ventilatory recovery and trunk control between tasks, actual performance remains below potential.

13. Carbon dioxide: why breathing becomes urgent

During intense exercise, carbon dioxide production increases. If ventilation is temporarily reduced by apnea and Valsalva, CO2 accumulates. The sensation of 'I cannot breathe anymore' after a very hard effort is strongly influenced by this respiratory load and the response of the chemoreceptors.

This explains a familiar scene after an event: a lift may last only a few seconds, yet the athlete needs much longer to bring ventilation back under control. Objective event duration and physiological stress are not the same thing.

14. Why do you sometimes see black after a heavy lift?

Some athletes describe blurred vision, black spots or near-fainting after maximal effort. Rapid changes in intrathoracic and arterial pressure, together with changes in cerebral perfusion and vasodilation in working muscle, may contribute to these sensations.

Experimental literature has shown that middle cerebral artery blood-flow velocity can change during intense static exercise associated with Valsalva. Dizziness or syncope should not, however, automatically be labeled normal. Severe or recurrent episodes, especially with chest pain, palpitations or disproportionate breathlessness, warrant medical evaluation.

15. What happens when you release the breath?

Releasing pressure is itself a physiological transition. Intrathoracic pressure falls, venous return changes, and active-muscle vasodilation may persist. The cardiovascular system rapidly moves from the effort state into recovery.

This is why recovery after a heavy repetition is not a minor detail. Moving the object is only half the problem. The body must restore ventilation, pressure and perfusion without losing postural control.

16. Valsalva can help performance, but it has a physiological cost

The literature does not support a simple conclusion that Valsalva is either 'good' or 'bad'. It can increase IAP and trunk rigidity and can be useful during very heavy efforts. At the same time, it raises hemodynamic stress and temporarily reduces ventilation.

The choice should be linked to load, duration and athlete status. A healthy athlete progressively exposed to heavy loads and without medical contraindication can use a well-learned bracing strategy. With severe hypertension, cardiovascular disease or other medical problems, the same technique should be individualized with a medical professional.

17. Controlled breathing versus Valsalva

The choice is not binary. Between completely free breathing and a pronounced Valsalva there are many strategies. Some allow exhalation during the concentric phase. Others use a short breath hold and release immediately after the critical point. In practice, the athlete should use the strategy that preserves enough stability without sacrificing unnecessary ventilation.

18. Table: respiratory strategy and likely effect

Controlled breathing | ventilation maintained | lower internal pressure | useful for submaximal and continuous work
Short apnea with bracing | ventilation temporarily reduced | IAP and ITP increase | useful for heavy, short efforts
Pronounced Valsalva | airflow blocked | greater internal pressure and pressor response | may occur near maximal effort
Exhalation during concentric phase | ventilation maintained | in some protocols lower arterial pressure than Valsalva | possible when stability demands allow

19. The lifting belt: mechanical aid, not a substitute for bracing

A belt can give the abdominal wall an external surface to brace against and can make pressure and rigidity easier to create. It does not generate IAP by itself and does not replace trunk control. The athlete still has to create active tension.

For Strongman, the belt is best viewed as one tool inside a larger strategy. If an athlete depends on the belt without understanding rib-cage position, pelvic control and breathing, the mechanical advantage may be limited.

20. Why body position matters

Body position changes the geometry of the cavities and the relationship between pressure, force and stability. That is why IAP and ITP values are not universal. Squatting, deadlifting, leg press and overhead work create different mechanical situations.

This is especially important when reading research. A result obtained during leg press cannot automatically be transferred to a yoke or a sandbag loading event. Science gives us mechanisms and observed ranges, not one number that applies to every Strongman event.

21. What does breathing look like in overhead events?

In Log Lift and Axle Press, trunk stability is essential, but the position of the arms and implement also changes respiratory mechanics. The ribs, diaphragm and abdominal musculature must work while the object is held in front of or above the body.

In one heavy repetition, the athlete may tolerate a brief pressor strategy. In a longer set or medley, however, there must be opportunities to ventilate rather than remain in continuous apnea. This is a trainable skill.

22. Training the respiratory muscles

Respiratory-muscle training can improve respiratory muscle strength and may improve some performance outcomes in certain athletic populations. A 2025 meta-analysis found effects on respiratory muscle strength and selected performance markers, with results depending on the protocol.

This does not replace general conditioning or event-specific practice. Transfer is more likely when the respiratory stimulus resembles the actual demands placed on the athlete.

23. What should a beginner learn about bracing?

A beginner does not need to copy an elite athlete's Valsalva immediately. The first goal is to learn posture, rib-cage and pelvic position, inhalation before the lift and circumferential trunk tension.

As load increases, the bracing strategy can become more pronounced. Progression should follow technical development and tolerance to load, not a race to produce the highest internal pressure.

24. When do breathing or bracing become a medical warning sign?

Chest pain during exercise, fainting, repeated near-fainting, unusual palpitations, disproportionate breathlessness or unusually difficult respiratory recovery should not automatically be explained by training intensity. These signs can have different causes and warrant evaluation.

This is especially important in athletes with hypertension, known cardiovascular disease, sleep-related breathing disorders or use of substances that can alter cardiovascular function.

25. Conclusion: there is no single 'Strongman breathing pattern'

During maximal effort, breathing becomes ventilation, stabilization and hemodynamics at the same time. The diaphragm, abdominal wall, thorax and cardiovascular system function together. IAP can contribute to trunk rigidity. ITP changes the pressures acting on the heart and vessels. Valsalva can support stability, but also creates an important pressor response.

For Strongman, the real skill is not producing the greatest possible pressure. It is producing enough pressure for the task, at the right moment and for the right duration. A maximal deadlift, Yoke Walk, Farmer's Walk, Log Lift and medley use the same anatomy, but not the same breathing strategy.

That is the useful lesson of physiology: bracing is not a ritual. It is a mechanical and physiological tool, and a good athlete learns not only how to create it, but when to let it go.

References and recommended reading

1. Hackett DA, Chow CM. The Valsalva manoeuvre: its effect on intra-abdominal pressure and safety issues during resistance exercise. J Strength Cond Res. 2012. doi:10.1519/JSC.0b013e31827de07d.

2. Hackett DA, Chow CM. Systematic review of intra-abdominal and intrathoracic pressures initiated by the Valsalva manoeuvre during high-intensity resistance exercises. Sports Med. 2019;49:1209–1220. doi:10.1007/s40279-019-01191-3.

3. MacDougall JD, Tuxen D, Sale DG, Moroz JR, Sutton JR. Arterial blood pressure response to heavy resistance exercise. J Appl Physiol. 1985;58(3):785–790.

4. MacDougall JD, McKelvie RS, Moroz DE, Sale DG, McCartney N, Buick F. Factors affecting blood pressure during heavy weight lifting and static contractions. J Appl Physiol. 1992;73(4):1590–1597. doi:10.1152/jappl.1992.73.4.1590.

5. Influence of breathing technique on arterial blood pressure during heavy weight lifting. J Appl Physiol. 1995. PubMed PMID: 7741618.

6. Pott F, et al. Middle cerebral artery blood velocity during intense static exercise is dominated by a Valsalva maneuver. J Appl Physiol. 2003. doi:10.1152/japplphysiol.00457.2002.

7. Xavier DM, Miranda JPP, Figueiredo PHS, Lima VP. The effectiveness of respiratory muscular training in athletes: A systematic review and meta-analysis. J Bodyw Mov Ther. 2025. doi:10.1016/j.jbmt.2025.01.010.

8. Opondo MA, Mujtaba MT, Shapiro BP. The Cardiovascular Physiology of Sports and Exercise. Clin Sports Med. 2015;34(3):391–404. doi:10.1016/j.csm.2015.03.004.

9. Paluch AE, Boyer WR, Franklin BA, et al. Resistance Exercise Training in Individuals With and Without Cardiovascular Disease: 2023 Update. Circulation. 2024;149:e217–e231. doi:10.1161/CIR.0000000000001189.

Editorial note: this article is educational and does not replace medical evaluation. Pressure values come from experimental protocols and are not personal training targets.