All force transmission begins and ends from the ground, and as you look at the human body, the first large muscle you meet is the bulging portion of your calf, called the gastrocnemius. The Greek translation, “stomach of the leg” refers to its shape, but could also refer to its critical role in human performance. The major responsibility of this muscle is to plantar flex the foot at the ankle, the same motion you use to step on the gas pedal in your car. This movement is one of the most critical sequences in generating force into the ground (GRF), as well as preventing a host of injuries, particularly its insertion into the Achilles tendon. This muscle generates massive amounts of tension, but also requires delicate flexibility to avoid rupture, so we should all be conscious of how we are treat this beast.
The main goal of sport is to create a neuromuscular solution to move more efficiently, a movement signatureTM (see Sparta Point). The gastrocnemius is unique in this process; a short ball, flowing into a very long tendon to store elastic energy during athletic movements that utilize the stretch shortening cycle (see Sparta Point). For example, in a vertical jump, when you start to descend in the loading or eccentric phase, the gastrocnemius does not lengthen like most muscles. Instead, the majority of elongation occurs at the tendon, in an attempt to store more energy to be released in the contraction that causes a jump upwards. This sequence of squatting down before jumping up has led many of us to find so much value in prescribing squats as an exercise to improve athletic movements like the vertical jump.
Following this concept, a 2012 study out of the University of Frankfurt examined squats, and its variations of depth, on vertical jump performance. After 2 days a week for 10 weeks, both full depth front and back squats presented significantly higher jump heights over the control and quarter squat groups. But Why? If you want to jump high and get stronger/stiffer gastrocs, why would you need to squat all the way down to the floor. After all, many athletes, especially track & field, utilize this quarter squat, fearful of losing the stiffness that is associated with fast stride rates, quick ground contacts.
The answer to these findings is that the gastrocnemius’s major role in movement signaturesTM is the DRIVE of force production. The muscle, particularly the tendon, needs to be able to stretch, to possess the ability to prolong the DRIVE of force production. However, athletes struggle to improve their DRIVE for 2 major reasons
- lack of flexibility at the ankle
- better strength at the end range (i.e. stability) of extension
While full depth squats and myofascial release can address the first obstacle of flexibility needs for DRIVE, a movement we have found to be superior for extension stability is the successive broad jumps shown in the video below.
Being both a plyometric and a very horizontally directed exercise, the DRIVE of force production by accentuating the arm swing, a key factor and subsequent benefit of this exercise.
Always squat full depth, your toes will probably go past your knees (see Sparta Point)
If you need ankle flexibility, roll out your gastroc and see rule #1
If you need more extension stability, perform broad jumps
Hartmann H, Wirth K, Klusemann M, Dalic J, Matuschek C, Schmidtbleicher D. Influence of squatting depth on jumping performance. J Strength Cond Res. 2012 Feb 15.