When athletes think about performance muscles, they usually picture glutes, quads, hamstrings or maybe even hip flexors. The calves rarely headline the conversation.
They are trained at the end of a session, thrown into a rehab plan as an afterthought, or ignored entirely until something hurts.
Yet in running and jumping sports, the calf complex is doing extraordinary work. It is managing body weight, storing and releasing elastic energy, stabilising the ankle, and contributing substantially to propulsion at high speeds.
So why are they treated like the forgotten cousin?
Let’s unpack what the calves actually do during sport and why they deserve far more respect in performance and rehab programming.
First, What Do We Mean by “Calves”?
The calf complex primarily includes:
- Gastrocnemius
- Soleus
Both muscles insert into the Achilles tendon and act to produce plantarflexion at the ankle. The gastrocnemius crosses both the knee and ankle, while the soleus acts only at the ankle.
Together, they form one of the most powerful muscle–tendon units in the body.
The Calves Are Major Contributors to Running Propulsion
For years, coaching cues have centred on “drive from the hips.” While the hip extensors are crucial, research consistently shows that the ankle plantarflexors contribute substantially to forward propulsion in running.
A widely cited biomechanics study by Novacheck (1998) in Journal of the American Academy of Orthopaedic Surgeons described the plantarflexors as the primary generators of power during late stance in gait and running.
More detailed modelling work by Dorn, Schache and Pandy (2012) in Journal of Experimental Biology examined muscle power contributions during running at different speeds. They found:
- The soleus and gastrocnemius were dominant contributors to positive work during stance.
- As running speed increased, ankle plantarflexor power increased substantially.
- The ankle joint generated more positive power than the hip at faster speeds.
That finding often surprises people. At high speeds, the ankle complex is not a passenger. It is a driver.
The Calf–Achilles Unit Is an Elastic Powerhouse
The Achilles tendon is one of the largest and stiffest tendons in the body. During running and jumping, the muscle–tendon unit behaves like a spring.
Seminal work by Komi (2000) in Scandinavian Journal of Medicine & Science in Sports described the stretch–shortening cycle and the role of tendon elasticity in enhancing performance.
Further research by Lichtwark and Wilson (2005) in Journal of Experimental Biology showed that during running:
- The Achilles tendon stores elastic energy as it stretches under load.
- The muscle fibres can operate more isometrically.
- Elastic recoil contributes significantly to propulsion.
In simple terms, the calf complex is not just contracting. It is recycling energy.
That elastic contribution improves running economy. Reviews in Sports Medicine have linked tendon stiffness and effective stretch–shortening cycle function with better running efficiency in endurance athletes.
This is not trivial. Over thousands of steps, small efficiency gains become large performance differences.
They Control Load Every Time Your Foot Hits the Ground
In running, vertical ground reaction forces often reach two to three times body weight. In jumping or cutting tasks, forces can be even higher.
The soleus, in particular, plays a major role in controlling tibial progression over the foot during mid-stance. It resists forward collapse and contributes to lower limb stiffness.
When calf capacity is insufficient, load is redistributed. Clinically, this is associated with issues such as:
- Achilles tendinopathy
- Medial tibial stress syndrome
- Plantar fasciopathy
The 2018 Clinical Practice Guideline for Achilles pain published in the Journal of Orthopaedic & Sports Physical Therapy supports progressive loading as first-line management, reinforcing the central role of calf strength and capacity in both performance and injury management.
The Soleus Is Not Just a “Slow, Endurance Muscle”
There is a common belief that the soleus is purely a low-threshold, endurance muscle that does not require heavy loading.
While it is predominantly composed of type I fibres, that does not mean it should only be trained with light loads.
Electromyographic and modelling studies show the soleus is highly active during running, particularly at higher speeds. The 2012 work by Dorn and colleagues demonstrated substantial soleus power output during fast running.
In practical terms, this means:
- Heavy slow resistance can be appropriate.
- High-load seated calf raises have value.
- Capacity, not just activation, matters.
Underloading the soleus is common in both gym and rehab settings.
Why Are Calves the Forgotten Muscle?
There are a few likely reasons:
1. They Do Not “Look” Powerful
Big glutes and quads are visually impressive. Calf hypertrophy is slower and more genetically influenced, which may bias training focus.
2. They Rarely Limit Basic Lifts
You can squat, deadlift and hip thrust significant loads without exposing the calf–Achilles unit to the same stretch–shortening demands seen in sprinting.
3. They Are Assumed to Be Trained Indirectly
People assume running, jumping or squatting is “enough.” But exposure to load is not the same as progressive overload.
4. They Often Get Attention Only After Pain
Calves enter the program reactively through Achilles or shin pain rehab, rather than proactively for performance.
What This Means for Sport Performance
If the ankle plantarflexors contribute heavily to propulsion, elastic energy return and running economy, then logically:
- Inadequate calf strength or stiffness may limit top speed.
- Poor calf endurance may impair repeated sprint ability.
- Insufficient tendon capacity may increase injury risk during spikes in load.
Systematic reviews consistently support progressive, heavy loading for Achilles tendon adaptation and pain reduction. While direct links between isolated calf strength gains and sprint performance are still being clarified, biomechanical evidence strongly supports their role in force production and energy return.
The evidence base is stronger for function than for isolated performance transfer, so claims about sprint time improvements should be made cautiously.
But from a load tolerance and mechanical perspective, the calves are central, not peripheral.
Practical Takeaways
If you are playing sport or doing rehab:
- Train both gastrocnemius and soleus
Include straight-knee and bent-knee variations. - Load them meaningfully
Heavy slow resistance has strong support in tendon rehabilitation literature. - Progress to high rate loading
Plyometrics and sprint exposures are essential for elastic adaptation. - Respect capacity during return to sport
Calf–Achilles tolerance often lags behind symptom resolution.
In Summary
The calves are not a cosmetic add-on at the end of a session. They are a primary engine of propulsion, a regulator of lower limb stiffness and a key component of elastic energy recycling during sport.
Biomechanical research consistently shows substantial ankle plantarflexor contribution to running power, especially at higher speeds. Clinical guidelines reinforce the importance of progressive loading for tendon health.
They are not the forgotten cousin because they are unimportant. They are forgotten because they are misunderstood.
If you care about performance, robustness and efficient movement, the calf complex deserves a front-row seat in your programming.
If you want to know how strong your calves should be, don’t miss our previous blog!
References
Dorn, T. W., Schache, A. G., & Pandy, M. G. (2012). Muscular strategy shift in human running: Dependence of running speed on hip and ankle muscle performance. Journal of Experimental Biology, 215(11), 1944–1956.
Komi, P. V. (2000). Stretch-shortening cycle: A powerful model to study normal and fatigued muscle. Scandinavian Journal of Medicine & Science in Sports, 10(6), 351–366.
Lichtwark, G. A., & Wilson, A. M. (2005). In vivo mechanical properties of the human Achilles tendon during one-legged hopping. Journal of Experimental Biology, 208(24), 4715–4725.
Martin, R. L., Chimenti, R., Cuddeford, T., et al. (2018). Achilles pain, stiffness, and muscle power deficits: Midportion Achilles tendinopathy revision 2018. Journal of Orthopaedic & Sports Physical Therapy, 48(5), A1–A38.
Novacheck, T. F. (1998). The biomechanics of running. Journal of the American Academy of Orthopaedic Surgeons, 6(6), 343–352.*
