I often get asked about calf size and how it relates to performance, especially from athletes who all seemingly want pythons between their knees and ankles, like Jack Grealish.
Jack Grealish has won 100+ fouls in each of the last three league seasons:
❍ 2017-18: 101
❍ 2018-19: 161
❍ 2019-20: 167
It's all in the calves. 🦵
— Squawka (@Squawka) September 10, 2020
With Grealish’s excellent run of form since the Premier League restart and during his time on international duty for England (although manager Gareth Southgate’s usage of the playmaker leaves plenty to be desired), a natural question arises: does calf size have any influence on key physical footballing abilities such as pace, agility, or power? To answer that question, we have to unpack some key items.
The first item is the relationship between calf strength, endurance and footballing performance. Calf strength comes in two forms: concentric and eccentric. Concentric is when the muscle is shortening while contracting, whereas eccentric is when the muscle is shortening while lengthening (see below).
Calf strength training has consistently been linked with improving pace and jumping ability. However, the most important aspect of calf force production is actually linked to the elastic properties of the calf and achilles tendon complex.
When the calf muscle contracts eccentrically, the achilles tendon is loaded like a spring with potential energy, and then recoils to generate a powerful force. Training that property of elasticity, and building tension capacity to optimize energy transfer and recoil, may be the critical bridge between calf function and performance.
Thus far I’ve spoken of the “calves” as a monolith. However, the calves consist of two distinct muscles: the meatier superficial gastrocnemius (which has a medial and lateral head), and the underlying flatter soleus muscle which fans out to the sides.
If you trace your thumb from your shinbone (tibia) inwards (medially) to the point where you drop off from the bone to softer muscle, that’s the soleus.
The soleus consists of predominantly (typically around 80%) type-1 muscle fiber types which are “slow-twitch, endurance” fibers. For reference, the gastrocs are typically closer to 50/50 ratio of type-1 and type-2 (“fast twitch, power” fibers). The higher proportion of type-1 fibers in the soleus speaks directly to its endurance role and constant activation during activities.
So now that you know how the different calf muscles function, is calf strength and endurance reflected by sheer calf size?
Yes and no. Yes, effective calf training (and thus increased calf strength and endurance) will lead to some hypertrophy (muscle growth) but there’s a significant genetic component to calf shape and size. Accordingly, there’s a large variance in calf size amongst the top physically performing footballers.
For example, Cristiano Ronaldo — a huge aerial threat, who possesses a monster leap — has well defined calves due to his low levels of body fat, but they aren’t massive in size. Meanwhile, I couldn’t pick Kylian Mbappe’s calves out of a lineup if I tried, and he boasted the highest recorded speed of any player in the Champions League last season.
Lastly, Adama Traore’s upper body, core, hips, and upper legs are extremely muscular but his calves are relatively svelte in comparison.
Thus, sheer calf size doesn’t tell us all that much about performance. Grealish’s massive calves are partly due to training, but their oversized nature is likely more so due to a genetic predisposition for larger calves. The key to understanding the relationship between the calf complex and footballing performance is understanding elastic recoil and transfer of energy.
However, there’s no way to gauge that without actually having the player in for a training session. In the meantime, we can all just continue being jealous of Jack’s calves.
Dr Rajpal Brar, DPT, is a physiotherapist, movement and mindfulness coach. He runs the LA-based wellness and athletic development/performance clinic 3CB Performance, and you can subscribe to his Youtube channel (which posts analyses of Lionel Messi and more) by going here.