Previously, we looked at what fascia is and what its functions are. In this post, were going to look at why its so important for movement.
In part one, we explained that fascia covers and connects a range of different structures in the body and creates a continuity of soft tissue. Work by Tom Myers (2014) suggests that this continuity of fascia is able to create connections between muscles in the human body. He has called these myofascial connections fascial lines, and full details can be found in his book Anatomy Trains (Myers, 2014). As therapists, a particular interest into how the fascial system is used in movement and how it impacts movement dysfunction is important.
Up to 12 lines have been suggested, but this post will only look at one as an example of how these lines aid in movement and force transmission.
The superficial back line as seen in Figure 1 below, originates at the plantar surface of the foot and travels all the way up the posterior of the body, over the scalp and finishes at the brow bone (Myers, 2014). Via muscle and fascial connections, it is suggested that these muscles are all linked and can work in synergy, instead of as independent actuators as previously thought.
Figure 1 – Plantar fascia, Achilles tendon, Gastrocnemius, Hamstrings, Sacrotuberous ligament, thoracolumbar (Thoracodorsal) fascia, Paraspinal (Erector Spinae) musculature, Trapezius, Occipitalis, Galea aponeurotica, Frontalis muscle
Additional research has looked at this line and shows that movement in one area such as the gastrocnemius, can actually effect the other areas in the line such as the hamstrings and spinal extensors. In can thus be suggested, that within these lines the muscles and fascia would work to transmit force throughout the body. When working with clients these lines should always be considered, as pain and dysfunction in one area can ultimately lead to issues away from the problem site.
As well as force transmission, the fascia has been shown to be key to another important function known as the catapult effect (Kram and Dawson, 1998). This catapult effect was initially studied in animals, primarily kangaroos and gazelles who’s length of jump was further than that which could be explained by force of contraction of their legs (Kram and Dawson, 1998). Researchers investigated this further, to find that the tendons and fascia of the legs were tensioned like an elastic band. The release of this energy was able to attribute to the large jump length (Kram and Dawson, 1998). The musculature alone wouldn’t have been able to create this jump length, but in synergy with the fascial catapult effect, was able to provide significant increase in jump performance.
This research has now been applied to human studies and a similar orchestration of loading has been shown to happen between human musculature and fascia (Sawicki et al, 2009). From these studies a similar kinetic storage capacity has been shown in humans in comparison to kangaroos (Sawicki et al, 2009). This mechanism is used not only when someone runs or jumps, but even in normal walking gait and contributes a significant portion of the energy used to move (Muller and Schleip, 2011).
As seen in figure 2 above, part B demonstrates how in conventional training e.g. a standing calf raise the muscle fibres change length to create the movement with no change in the fibres of the fascia. Part A shows an oscillatory movement such as a jump, in which a change in both muscle and fascia fibre length can be seen due to the elastic properties of the exercise.
While previously fascia was thought to not have an important impact on movement, it is now clear to see that through the fascial lines it plays a huge role in force transmission, as well as storing and releasing energy via the catapult effect. These are two of the key concepts behind fascia in movement, however there are still a range of other important concepts. This begins to show the importance of the fascial system in human movement, and if you’re are, or are working with someone with dysfunction, these concepts may be worth thinking about!