When the Pelvic Floor Won’t Let Go: Using mTrigger Biofeedback for Dyssynergic Defecation

Constipation is often approached as a problem with the simple solution of increasing fiber and water intake. However, it is much more: stool consistency, bowel motility, stress, diet, movement, and pelvic floor muscle function. For some patients, however, the problem is occurring at the final step: the muscles needed to allow stool to pass are not coordinating appropriately.

Dyssynergic defecation (DD) is a functional defecatory disorder in which the abdominal, rectoanal, and pelvic floor muscles do not work together appropriately during a bowel movement. Rather than relaxing while abdominal pressure helps propel stool, the pelvic floor or anal sphincter may fail to relax—or may paradoxically contract—creating resistance to evacuation. Inadequate propulsive force can also contribute. 

For pelvic health physical therapists, this makes DD an ideal example of why pelvic floor treatment is not always about strengthening. Sometimes the goal is learning to let go at the right time.

 Is Happening During Dyssynergic Defecation?

Normal defecation requires a coordinated sequence. Intra-abdominal pressure increases while the puborectalis and external anal sphincter relax, allowing the anorectal angle to widen and stool to pass. In DD, that coordination breaks down. The pelvic floor may remain active, the anal sphincter may contract, or the patient may be unable to generate an effective propulsive force.

Patients may report excessive straining, incomplete evacuation, hard stools, infrequent bowel movements, abdominal fullness, or the need to use digital maneuvers to assist evacuation.

Because symptoms alone cannot reliably distinguish DD from other causes of constipation, appropriate medical evaluation is important. Diagnosis may incorporate digital rectal examination, anorectal manometry, balloon expulsion testing, and defecography. 

What Does Physical Therapy Focus On?

The goal of rehabilitation is to restore coordination between pressure generation and pelvic floor relaxation, not simply make the pelvic floor stronger.

Treatment commonly includes education regarding pelvic floor anatomy and normal defecation, diaphragmatic breathing, appropriate toileting posture, bowel habits, and strategies for generating abdominal pressure without simultaneously tightening the pelvic floor. Biofeedback training then gives the patient an opportunity to practice this coordination with real-time information about muscle activity. 

Depending on the individual patient, treatment may emphasize:

• relaxing the pelvic floor and anal sphincter during bearing down
• coordinating diaphragmatic breathing with abdominal pressure
• reducing paradoxical pelvic floor contraction
• improving awareness of unnecessary resting tension
• practicing appropriate toileting mechanics and positioning
• integrating abdominal and pelvic muscle function so the patient can create pressure while maintaining an open outlet.

Making Relaxation Visible with mTrigger

This is where surface EMG biofeedback can be especially valuable.

A patient may understand the instruction to “relax your pelvic floor,” yet have little awareness of whether relaxation is actually occurring. Surface EMG provides an external representation of muscle activity. Research on DD has used surface EMG electrodes on either side of the external anal sphincter to identify inappropriate activation during attempted defecation and to provide visual feedback during retraining. 

Using appropriate external electrode placement, mTrigger can apply this same biofeedback principle in the clinic. The clinician can first help the patient recognize the difference between contraction and relaxation. Rather than focusing on how high the activation signal can go, the treatment target for DD may often be the opposite:
Can the patient allow the signal to decrease while maintaining an appropriate breathing and bearing-down strategy?

This turns an abstract instruction—“let go”—into something the patient can see.

Progress From Relaxation to Coordination

Once a patient can decrease pelvic floor activity in a simple position, mTrigger can be incorporated into more functional retraining.

The patient can practice diaphragmatic breathing while monitoring resting activity, then progress to a gentle bearing-down maneuver. The clinician and the patient can watch for an unwanted increase in the mTrigger signal as abdominal pressure increases. If pelvic floor activation rises instead of falling, the patient receives immediate information that the strategy needs to change.

Research-based biofeedback protocols similarly focus on increasing intra-abdominal pressure while decreasing anal canal pressure and preventing paradoxical pelvic floor contraction. Training often progresses to simulated defecation and functional practice. 

Biofeedback should therefore complement—not replace—breathing instruction, positioning, bowel education, manual assessment, and functional retraining.

What Does the Evidence Say?

Biofeedback is particularly well supported for dyssynergic defecation. A review of randomized trials reported symptom improvement rates of approximately 70%–80%, with benefits that may persist long-term. In one trial, 80% of patients receiving EMG biofeedback reported major improvement compared with 22% treated with laxatives, and improvement was maintained at 24 months. 

More recently, a 2026 prospective study found improvement in stool form, constipation symptoms, or quality of life in 71.1% of patients undergoing biofeedback therapy. 

mTrigger is a practical way for clinicians to apply the sEMG motor-retraining principles supported by research.

Summary

Dyssynergic defecation is fundamentally a problem of coordination. Effective bowel emptying requires the patient to generate appropriate abdominal pressure while simultaneously relaxing the pelvic floor and anal sphincter. For many patients, simply being told to relax is not enough.

mTrigger can help therapists make pelvic floor activity visible, allowing patients to recognize unwanted activation, practice relaxation, coordinate breathing and pressure generation, and gradually develop a more effective defecation pattern. In this population, the value of biofeedback is not about creating a stronger contraction—it is about helping patients learn when the pelvic floor should be active and, just as importantly, when it should let go.

mTrigger's Pelvic Protocol

More Ways to Use mTrigger Biofeedback

References

1. Sadeghi A, Akbarpour E, Majidirad F, et al. Dyssynergic defecation: a comprehensive review on diagnosis and management. Turk J Gastroenterol. 2023;34(3):182-195. doi:10.5152/tjg.2023.22148.
2. Özin Y, Öztürk Ö, Tenlik İ, et al. Efficacy of combination of biofeedback therapy and pelvic floor muscle training in dyssynergic defecation. Acta Gastroenterol Belg. 2021;84(4):577-583. doi:10.51821/84.4.008.
3. Mobing H, Sethy P, Nania M, Samanta R, Debnath P. Efficacy of biofeedback therapy in patients with dyssynergic defecation: a hospital-based study in Eastern India. Cureus. 2026;18(5):e109606. doi:10.7759/cureus.109606.
4. Skardoon GR, Khera AJ, Emmanuel AV, Burgell RE. Review article: dyssynergic defaecation and biofeedback therapy in the pathophysiology and management of functional constipation. Aliment Pharmacol Ther. 2017;46(4):410-423. doi:10.1111/apt.14174.