How Does Core Musculature Affect Your Performance? Research from Exercise Physiology

Many recreational athletes associate core training with abdominal muscles, a well defined six-pack, and aesthetics, whereas professionals, athletes, and coaches see something quite different: A system which transfers force and power between the lower and upper body, -influencing how much of that force actually reaches a paddle, a swim stroke, a kick, or a throw. And one important aspect behind physical therapist Tor Einar Sandvikmoen's initiative: How much force (Newtons and Watts) the core itself is capable of generating – hence the term core capacity.

The question many people should ask themselves – athletes and fitness enthusiasts alike – is not "is my core strong enough," but rather "does my core function to my sporting requirements."

The answer lies in the variation between 1) adaptive stability – the ability to adjust tension synchronized with movement, 2) pure rigidity – meaning maximizing and statically bracing the core, and 3) core capacity – the ability to generate power under changing conditions while maintaining dynamic stability.

This article looks at what the research actually shows regarding this, including our own two recent studies, both published in Frontiers.

What does “core musculature” mean - and why is it more than abs and six-pack?

The core encompasses not only the rectus abdominis (the six-pack), but an entire corset of musculature: various layers of muscles in the abdominal region and around the spine, the pelvic floor, the diaphragm, and some hip muscles, which together provide the spine and pelvis with dynamic stability and, to some extent, rigidity.

In their classic 2006 review, Kibler and colleagues described the core as the foundation for what they termed "proximal stability for distal mobility" – a principle of a stable midsection (trunc) being the prerequisite for limbs to move quickly and precisely (Kibler, 2006).

Without this foundation, power dissipates as unnecessary movement or energy instead of being transferred to the ground, the water, or the equipment. https://pubmed.ncbi.nlm.nih.gov/17685697

This is not merely a theoretical point. The core functions as a link in what is often called the kinetic chain – the sequence of joint movements and muscle activations that generate and transfer power from the legs, through the hips and pelvis, up through the spine, and out into the arms.

The transfer of force between muscles can occur in multiple directions, and Tom Myers' Anatomy Trains provides a holistic, anatomical description of various connections/pathways in the body, through which force can be transferred – thus influencing movement and stability.

If the most central link fails or fades, the athlete loses power regardless of immencely strong arms or legs. In worst-case scenario, the "lost" force enters other structures in the body – such as ligaments, supporting joints, etc. – creating irritation or, at worst, injuries.

Force Transfer in Sport-Specific Movements

In sports such as swimming, paddling, throwing, running and others, force production is rarely linear. The body rotates, twists, curves and stabilizes while simultaneously accelerating, pivoting and so on. In this case, the role of the core is pretty clear: It must both prevent unwanted movement in the spine and, at the same time, allow for controlled movement and rotation where the sport requires it.

Kibler describes this as a combination of static and dynamic stability, where the muscles alternate between locking and allowing movement depending on the phase of the motion.

This has a direct impact on how one should train the core for sport-specific performance. A core that is only trained to hold a static plank is not necessarily equipped to handle the rapid, dynamic, and often asymmetrical forces that occur in actual sports performance.

Adaptive Stability Versus Rigidity – What Does the Research Show?

A common misconception is that "the more tension the better" – that maximum, sustained bracing of the core provides the best protection and optimal transfer of forces. Research on sensorimotor control significantly nuances this view.

Studies on how the nervous system regulates core stability show that it is not the muscle's sheer strength that determines stability, but rather the ability to time and graduate the activation correctly in relation to the external load (sensorimotor control and core stability).

In other words: a core that is constantly "stiff" loses the ability to react quickly enough to variations and unforeseen forces – which is often a requirement in many sports.

This is also supported by research on runners, where core and lumbopelvic stability is linked to running economy and risk of injury, in which stability is understood as controlled movement and correct timing of muscle activation, rather than total rigidity in the lower back (core and lumbopelvic stabilization in runners).

The exception is perhaps maximally heavy powerlifting, which requires "bracing" or maximum tightening of the body's muscular corset. But even under such conditions, technique, timing, and movement dynamics play a significant role.

Adaptive or dynamic stability is therefore about being able to continuously adjust the level of tension – bracing when needed, and releasing when the movement requires mobility.

New Research: Heavy Core Training Has a Measurable Effect on Performance

A concrete example of how heavier and dynamic core training translates into practice, backed in our own pilot study published in Frontiers in Physiology in 2025. Saeterbakken and colleagues examined eighteen national-level junior athletes – kayak sprinters and swimmers with an average age of 17.1.

The results showed a 12.8 percent increase in peak power during a paddle sprint and an 11.9 percent increase in average power, both being statistically significant. Interestingly, maximal isokinetic force and power did not change during the same period. https://doi.org/10.3389/fphys.2025.1617104

This last finding precisely illustrates the point regarding adaptive stability: dynamic, heavy core training transfers to dynamic force production in the core, measured as increased effect at the tip of a paddle-ore, whereas pure isokinetic force did not change correspondingly.

The authors conclude that dynamic, high-intensity core training is a viable option to include in a periodized pre-season program, particularly for sports where upper-body power is crucial for performance, such as paddling and swimming.

Exercise Complexity Impacts Muscle Activation

Another relevant publication of ours in Frontiers in Sports and Active Living in July 2026 examined how exercise complexity affects core muscle activation among 28 recreational athletes performing seven bodyweight exercises (Andersen et al., 2026). The findings indicate that increased complexity yields higher core muscle activation—most notably in the primary targeted muscle—alongside greater perceived exertion. You may access the study via Frontiers in Sports and Active Living. https://doi.org/10.3389/fspor.2026.1845995.

This is practically relevant because it shows that one does not necessarily need to add external load (weights, resistance bands, etc.) to increase the training stimulus in the core; increasing movement complexity – for example, through a smaller base of support, more unstable positions, or multi-joint movements – can in itself provide significantly higher activation. Several of the exercises used in this study are documented and openly shared in the publication, and similar progressions are also demonstrated in our own app, precisely because they are research-based.

Breathing, Diaphragm, and Core Stability

The function of the core is also closely linked to breathing mechanics. The diaphragm is an integral part of the core cylinder, along with the pelvic floor and the oblique abdominal muscles, among others. A randomized controlled trial on professional dancers found that targeted training of the inspiratory muscles increased the thickness of the diaphragm and improved respiratory muscle strength, balance, and core stability (inspiratory muscle training in dancers).

This supports the view that core stability cannot be reduced to sheer muscle strength in the abdomen and back. Breathing patterns and intra-abdominal pressure are part of the same system, influencing how effectively force can be transferred through the body under load.

Practical Implications for Athletes, Coaches, and Professionals

For practitioners, this implies several things. First, core training should be evaluated on a sport-specific basis: a paddler or a swimmer who requires explosive upper-body power, likely derives a different benefit from heavy, dynamic core training than a runner, who primarily needs controlled stability in the lower back and pelvis under low-dose and repetitive loading.

Second, one should not assume that more static core strength is always a main goal – and consequently implement well-known, grueling sessions with plank exercises and the like. As the study by Saeterbakken and colleagues demonstrates, heavy and dynamic core training can yield measurable gains in upper-body performance, even without improvements in maximal isokinetic force.

Third, the training stimulus can be adjusted by altering movement complexity rather than simply adding more weight, as documented by Andersen and colleagues.

Physical therapists and other professionals should also be aware that sensorimotor control – the timing and graduation of muscle activation – is just as important as sheer strength, particularly in rehabilitation and injury prevention. Furthermore, for some athletes, inspiratory muscle training (incorporating correct breathing techniques) can have a valuable supplementary effect on core function.

Conclusion

The core musculature is far more than the aesthetics of the abdominal muscles – it is the system that determines whether power produced in the legs actually reaches the arms, paddle, or swim stroke.

The term core capacity reflects how much power can be generated internally within the system itself. The potential for power production within the core itself – using modern and heavier dynamic core exercises – has largely been overlooked in many settings. Backed by our own research and other supportive litterature, we aim to lead the way in this change of paradigm within core training.

Recent research, including our own studies on junior paddlers and swimmers as well as on exercise complexity in recreational athletes, shows that heavy and dynamic core training provides a measurable activation of the core musculature, with performance gains that differ from pure static strength.

The crucial distinction is between adaptive stability – where the core adjusts tension according to the demands of the movement, and rigidity – where one only trains for maximum, static bracing.

For athletes, coaches, and professionals seeking performance-enhancing core training, the conclusion is clear: question how the core needs to function within the specific sport, not just how "strong" it is. And make adjustments accordingly.

Sources

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• Kibler, W. B., Press, J., and Sciascia, A. (2006). “The role of core stability in athletic function.” Sports Medicine, 36(3), 189–198.
• Prieske, O., Muehlbauer, T., and Granacher, U. (2016). “The role of trunk muscle strength for physical fitness and athletic performance in trained individuals: A systematic review and meta-analysis.” Sports Medicine, 46, 401–419.
• Reed, C. A., Ford, K. R., Myer, G. D., and Hewett, T. E. (2012). “The effects of isolated and integrated ‘core stability’ training on athletic performance measures: A systematic review.” Sports Medicine, 42(8), 697–706.
• Short et al. (2025). Library reference retained from the source article.