The clench test is a simple diagnostic test used to assess the strength and coordination of the pelvic floor muscles. It is commonly used by physical therapists and other healthcare providers to evaluate pelvic floor dysfunction in patients with urinary incontinence, pelvic organ prolapse, or other pelvic floor disorders.
What is the purpose of the clench test?
The main purpose of the clench test is to determine a patient’s ability to voluntarily contract and relax the pelvic floor muscles. Specifically, the test allows assessment of:
- Pelvic floor muscle strength
- Pelvic floor muscle endurance
- Coordination and symmetry of pelvic floor muscle contraction
- Patient’s ability to isolate and consciously control pelvic floor muscle contraction
This information helps identify impairments or dysfunction that may be contributing to the patient’s symptoms. It also provides a baseline to monitor progress with pelvic floor muscle training.
How is the clench test performed?
The clench test is performed in the following steps:
- The patient empties their bladder and then lies down on their back with knees bent and legs apart.
- The provider instructs the patient to tighten their pelvic floor muscles as if trying to prevent passing gas or avoid urinary leakage. Cues are given such as “squeeze and lift” or “pull up and in.”
- The patient holds the contraction for as long as they can, up to 10 seconds. They then relax the muscles fully.
- This sequence is repeated 3-5 times.
- The provider evaluates the strength, duration, coordination and repetition ability of the contractions.
- Variations may include testing in sitting or standing, or asking the patient to contract the muscles quickly or repeatedly.
How is the test results evaluated?
The provider evaluates several aspects of the pelvic floor muscle contraction during the clench test:
Strength
This is rated on a modified Oxford scale from 0 to 5:
| Grade | Description |
|---|---|
| 0 | No discernible muscle contraction |
| 1 | Flicker of muscle contraction felt but no visible lift/squeeze |
| 2 | Weak muscle contraction felt and visible lift/squeeze |
| 3 | Moderate contraction felt and visible lift/squeeze |
| 4 | Good contraction felt and visible lift/squeeze |
| 5 | Strong contraction felt and visible lift/squeeze |
Endurance
This is measured by the length of time the contraction can be sustained, up to 10 seconds. Normal endurance is 10 seconds.
Repetitions
This evaluates how many successive contractions can be performed while maintaining strength and endurance. Ability to complete 5 repetitions is considered normal.
Coordination
This assesses symmetry and smoothness of the contraction. Ideally both sides contract equally and steadily without shaking or quivering.
Isolation
This evaluates whether the patient is able to contract the pelvic floor without contracting other muscles like abdominals, buttocks or inner thighs. Contraction of other muscles indicates poor isolation ability.
What is considered a normal clench test?
A normal clench test shows:
- Grade 3-5 strength
- 10 second endurance
- 5 repetitive contractions
- Smooth, symmetric contraction
- Isolation to pelvic floor muscles only
Scores lower than this may indicate underlying pelvic floor muscle dysfunction.
How can the clench test help diagnose pelvic floor disorders?
Abnormal clench test findings can help identify the nature of pelvic floor dysfunction contributing to a patient’s symptoms:
Urinary incontinence
Weakness (grade 1-2 strength) indicates stress urinary incontinence. Poor endurance and early fatigue with contractions can signify urge urinary incontinence.
Pelvic organ prolapse
Severe weakness (grade 0-1 strength) implies failure of pelvic floor support. Inability to voluntarily contract indicates damage to pelvic floor nerves.
Pelvic pain disorders
Overactivity and poor relaxation of pelvic floor muscles correlates with increased muscle tone and spasm which causes pain. Weakness indicates dysfunction of muscle support.
Constipation/bowel dysfunction
Dyssynergia and inability to coordinate relaxation and contraction of pelvic floor and abdominal muscles leads to dyssynergic defecation.
Sexual dysfunction
Underactivity due to weakness or overactivity due to spasm can both impair sexual function. Failure of pelvic floor relaxation is associated with dyspareunia.
How are clench test results used to guide treatment?
Information from the clench test directs specific selection of appropriate interventions for the patient’s pelvic floor disorder:
Pelvic floor muscle training
Strengthening and endurance exercises are prescribed for underactive muscles. Coordination and relaxation training helps overactive spastic muscles.
Biofeedback
Poor conscious control shown on the test indicates biofeedback will improve ability to properly contract and relax pelvic floor muscles.
Vaginal cones
These weighted cones provide resistance to strengthen weak pelvic floor muscles identified on the test.
Electrical stimulation
This modality is used to strengthen severely weak muscles graded 0-1 that cannot voluntarily contract on the test.
Trigger point release
Manual techniques like internal vaginal Thiele massage alleviate high muscle tone and spasm found on the clench test.
Bowel/bladder retraining
Timed voiding and bowel movement schedules are useful for overactive clenched muscles and urge incontinence.
Postural/movement re-education
Improving lumbopelvic stability and relaxing hypertonic muscles helps coordinate contraction and relaxation.
What are limitations of the clench test?
Some limitations of the clench test include:
- Results depend on patient’s ability to understand how to contract pelvic floor muscles
- Does not assess involuntary function of pelvic floor
- Muscle strength graded subjectively so inter-rater reliability may vary
- Does not identify specific anatomical defects or damage
- Does not assess function during activities like coughing or lifting
Conclusion
In summary, the clench test is a simple and useful assessment tool to evaluate pelvic floor muscle function. It provides valuable information about strength, endurance, coordination and voluntary control. By identifying impairments, it guides targeted treatment selection to address specific pelvic floor deficiencies contributing to the patient’s symptoms and dysfunction. When combined with a full history and examination, it aids diagnosis of pelvic floor disorders. With its ease of administration and minimal equipment needs, the clench test is ideally suited for use in outpatient physical therapy clinics. Some limitations exist, but overall it serves as a convenient first-line assessment of the pelvic floor.