Calf strain? Calf raises alone won’t suffice!
Injured your calf? Think a few simple body weight calf raises will get you sorted? Think again!
Firstly let's look at the contribution of the calves when running, and in short, they do a LOT of work: The larger of the calf muscles, the soleus, is highly important for running taking 6.5-8 times body weight of force, whilst the other calf muscle, the gastrocs, takes 2-3 times body weight (Dorn 2012). The Achilles tendon also needs to absorb a high amount of force when running, equalling 4.15-8.0 body weights of force (Gheidi 2018, Sinclair 2015, Willy 2016).
So how do we replicate this high amount of force going through the calf and achilles without running (upto 8 x body weight)? Does this mean we need to put 7 times our body weight on our back and do a calf raise? Fortunately not. Now it’s outside the scope of this blog to discuss further, but due to the moment arms of the foot and Achilles, an unweighted single leg heel raise equates to 3.98 body weights of force through the calf and Achilles (Gheidi 2018).
Therefore to achieve 6.5-8 times body weight through the calf and Achilles, you need to perform a single leg calf raise with an ADDITIONAL 60% - 100% bodyweight.
Now a weighted calf raise might be able to equal the force required to that of running, but what about the loading rate? Unfortunately it doesn’t get near that. A single leg calf raise only reaches 25% of the loading rate of running (see the graph below) (Gheidi 2018).
So what does this mean? Well it means if we want to strengthen the calf & achilles to try and match the demands of running, you can NOT just simply do weighted calf raises. You need to supplement your rehab with plyometric exercises (ie. jumping, hopping, skipping, pulsing ect) and/or dynamic sled pushes.
Lastly, no exercise in isolation loads the calf and Achilles like running does, so ultimately you need to safely and gradually get back to running!
Dorn, T. W., et al. (2012). "Muscular strategy shift in human running: dependence of running speed on hip and ankle muscle performance." J Exp Biol 215(Pt 11): 1944-1956.
Gheidi, N., et al. (2018). "Achilles tendon loading during weight bearing exercises." Phys Ther Sport 32: 260-268.
Sinclair, J., et al. (2015). "Influence of running shoes and cross-trainers on Achilles tendon forces during running compared with military boots." J R Army Med Corps 161(2): 140-143.
Willy, R. W., et al. (2016). "Patellofemoral Joint and Achilles Tendon Loads During Overground and Treadmill Running." Journal of Orthopaedic & Sports Physical Therapy 0(0): 1-31.