It has been over 5 years since I wrote my Trigger Point 101 article, which offered a basic explanation of trigger points for strength and conditioning coaches. The article is still one of the most popular on the site and in a recent discussion with Dr. Phil Snell, regarding Trigger Points, I figured I’d circle back around and revisit the topic.
Questions About Trigger Points
Trigger points are still a hotly debated topic and my aim is not to get into a name convention about what we should call them (I’ll let the researchers sort that one out). What we do know is that there are two main kinds of trigger points we may be dealing with:
- Active Trigger Points – These are trigger points that are currently referring their characteristic pain response. For example, you have some pain in the anterior shoulder and when I push on your infraspinatus it refers the pain you are currently feeling and after some time that pain dissipates and goes away.
- Latent Trigger Points – These are the trigger points that only produce pain when they are provoked. Using the above example, you would not be experiencing any anterior shoulder irritation, however, if I started to massage your infraspinatus you end up feeling a referral pain in your anterior shoulder, which dissipates after treatment.
One thought that Dr. Snell raised in our discussion was centered around the idea that maybe trigger points don’t ever go away. Perhaps they just modulate between being latent and being active based on activities that we perform in our daily lives.
This is certainly an interesting hypothesis and it has been shown in a number of studies that latent trigger points are very common in asymptomatic subjects (Fernandez-de-Las-Penas C, Dommerholt J. 2014.). The more that I think about it, the more I think that maybe trigger points are a potential ramification of being upright. After all, we do tend to see a lot of the same muscles develop trigger points and these are often the same muscles that we need to hold us up against gravity (Upper Traps, Gastroc, Erectors, etc). Additionally, many of the muscles that commonly develop trigger points are those that Janda suggested had the tendency for hypertonicity:
Thinking more about Dr. Snell’s assumption and the idea that trigger points may be related to us being upright I believe there are some important applications regarding sport and sports preparation.
Implications For Sport
Training for sport is brutal. Athlete’s log long hours in the gym and long hours on the field/court/track, day after day, month after month, and year after year. On top of that the movements tend to be rather repetitive in nature, in order to develop specific skills and technique, leading to overuse injuries and unique strain patterns.
The Integrated Hypothesis of Trigger Points (McPartland JM, Simons DG. 2006.) encompasses multiple physiological components:
“The ‘integrated hypothesis’ regarding the etiology of myofascial trigger points states that each trigger point has a sensory component, a motor component, and an autonomic component. The hypothesis encompasses local myofascial tissue, the CNS, and systemic biomechanical factors.”
This hypothesis allows us a to paint a very broad picture of how an athlete’s soft tissue may react to the stresses that we place upon them in training and competition as well as how their daily lives may impact soft tissue structures. If trigger points don’t ever go away but rather just modulate from latent to active based on activity, as Dr. Snell suggested, and if they are a product of being upright, perhaps the goal of soft tissue therapy in sport should be to aid in supporting the physiological system to prevent increased trigger point activity (Note: Of course this is not just specific to soft tissue therapy but the program as a whole. Because trigger points can be influenced by multiple factors – nutrition, hydration, overuse, repetitive strain, psycho-emotional stress, etc – it is important to manage all stressors within the training program.).
The concept of latent trigger points is an interesting one. While trigger points may not actively be referring a pain pattern it has been suggested that their presence may disturb motor function leading to issues such as muscle weakness, inhibition, increased motor irritability, muscle cramps, or altered muscle recruitment patterns (Fernandez-de-Las-Penas C, Dommerholt J. 2014., Shah, 2008.,Ibarra, 2011). Recently, it has been suggested that trigger points may play a roll in central sensitization (Fernandez-de-Las-Penas C, Dommerholt J. 2014.) due to their ability to activate and maintain sensitization of central pathways. This may happen through ongoing sensitization of previously silent dorsal horn neurons brought about by various neuropeptides and inflammatory compounds, such as, bradykinin, CGRP, substance P, TNF-a, IL-6, etc. (Shah, 2008.). Thus, because everyone posses latent trigger points, because latent trigger points can become active trigger points, and because latent trigger points may negatively influence motor function and increase inflammatory compounds that can make an athlete more adverse to changes in their dorsal horn neurons, managing soft tissue health and treating latent trigger points to help manage their activity and prevent them, as best as possible, from becoming active may be a good strategy.
Treatment of Latent Trigger Points in Healthy Subjects
A recent study by Grieve and colleagues (2013) set out to evaluate the immediate effect of restricted ankle joint dorsiflexion ROM after a single treatment of latent trigger points in recreational runners. The twenty-two runners in the study were tested to have restricted ankle dorsiflexion with both a straight knee (gastroc) and knee bent to 90 degrees (soleus). The presence of trigger points were confirmed with a palpatory assessment. The subjects served as their own control and were randomly assigned to either an intervention or control session, 1 week apart.
- Lewit’s barrier release concept was applied to trigger points in the gastroc and/or soleus (which were marked on the client during the palpatory assessment to ensure accuracy). The Lewit barrier release concept is performed by applying increased thumb pressure over the marked trigger point until the first barrier of tissue resistance is felt. This barrier was perceived to be ‘tender’ but not ‘painful’ to the subject. The pressure is maintained until the therapist felt a release in muscle tension.
- Following the release of muscle tension a 10sec passive stretch was applied to the treated muscle.
- This sequence of treatment and stretch were performed for a 10min treatment period.
- During the control session, subjects performed a 10min supervised rest period.
- Ankle dorsiflexion was measured at baseline and post 10min treatment/rest period for both groups.
Findings & Relevance
Post treatment measurements of dorsiflexion revealed a 4 degree and 3 degree increase in soleus and gastroc dorsiflexion, respectively. Both findings were clinically and statistically significant.
This paper confirms a few of the concepts discussed above:
- First, latent trigger points, while not referring pain, may negatively influence motor function and range of motion.
- Second, a small amount of time (10min) was required in order to see clinically relevant improvements in ankle dorsiflexion in asymptomatic recreational runners.
Treatment of soft tissue structures as part of the training process may be beneficial for keeping tissue healthy and keeping the athlete training. Perhaps some of the ROM benefits in this study can be had with the FOAM ROLLING that athletes perform prior to warm up and training.
Soft tissue treatment has an important place within a structured training program and the idea that we should be treating latent trigger points in athletes as a means of preventing them from becoming active, enhancing joint function, and decreasing tissue tension is an interesting one. Latent trigger points may be a product of being upright as well as the tasks the athlete commonly performs. Understanding the sport and the soft tissue structures which are stressed in that sport may be helpful when planning a treatment session. Treatment can be performed via hands on therapy, dry needling techniques, or foam rolling. As indicated in the paper above by Grieve and colleagues, treatment does not need to be overly painful or aggressive. The Lewit barrier concept takes the tissue to the first barrier of resistance and works within the individual’s level of discomfort. I typically use a 1-10 scale and ask the client to not let me get over a 7 >> Some may refer to this as a “good hurt” and treatment of trigger points has been shown to bring about a favorable shift in the autonomic nervous system (Delany JP, 2002.). Many of the trigger points line up with the Stecco centers of coordination and treatment to those regions, with either compression (as in the Lewit barrier concept) or friction (as in the Stecco treatment approach) may be beneficial. It is common to follow treatment of a trigger point, once there has been a decrease in tissue tension and a decrease in client sensation, with some form of stretch, as used in the study by Grieve and colleagues above. The types of stretches I commonly apply are Muscle Energy Techniques, some form of active isolated stretch, a low grade passive stretch (as indicated in the Grieve study), or some type of pin and stretch technique. Finally, it is important to educate the athlete on self-care strategies and remember that trigger points are multifaceted and things such as nutrition, hydration, sleep, stress, etc, all play a roll in their expression.