Interrater Reliability among Novice Raters in the Assessment of Pelvic Floor Muscle Tone Using the Reissing Tone Scale

Abstract

Purpose: The authors sought to determine the interrater reliability among novice raters of intra-vaginal manual assessment of pubococcygeus muscle tone in women using the Reissing tone scale (RTS). Method: Three graduating physiotherapy students (novice raters) and one experienced pelvic floor physiotherapist assessed 31 female participants (aged 20–66 y). Assessors gave RTS scores for pubococcygeus tone at three intra-vaginal locations (6:00, 9:00, and 3:00). Interrater reliability was determined for the novice raters using a two-way random single-measures absolute agreement intra-class correlation coefficient (ICC). Spearman rank correlation (SRC) analysis determined the correlation between the novice and expert scores. Results: The ICC values for the novice raters were 0.523, 0.274, and 0.336 at 6:00, 9:00, and 3:00, and the SRC values between the novice and expert raters were 0.580, 0.320, and 0.340. Conclusions: The novice raters demonstrated low to moderate interrater reliability for intra-vaginal manual assessment of pubococcygeus tone. This result indicates that manual assessment of pelvic floor muscle tone is not reliable enough to use as a stand-alone test to guide treatment, at least for physiotherapists with limited clinical experience.

Abnormal pelvic floor (PF) muscle tone may be present in many patients with urinary incontinence,¹ pelvic pain,² and a range of other pathologies. PF physiotherapy may be considered a first-line intervention for these conditions, given its low cost and minimal adverse effects,^3,4 and it has been endorsed by the Canadian Urological Association,⁵ International Urogynecological Association, and International Continence Society.⁶ Physiotherapy interventions, such as manual techniques, relaxation, and exercise, can address both hypo- and hypertonicity of the PF muscles.^2,7 To guide treatment, however, it is important that physiotherapists have a reliable and evidence-based clinical approach to evaluating PF muscle tone.

The Reissing tone scale (RTS) is a simple and clinically accessible method of classifying PF muscle tone, defined as resistance to deformation, using digital palpation. It is based on a specific assessment approach developed by physiotherapists with expertise in PF rehabilitation and is described by Reissing and colleagues.⁸ The RTS grades tone on a 7-point ordinal scale, ranging from –3 to 3, where 0 = normal tone, –3 = very hypotonic, and +3 = very hypertonic (see Table 1). This scale, and the assessment approach on which it is based, is used in clinical practice and in published research,^8–10 although its reliability has not been fully assessed.

Table 1 .

Reissing Tone Scale Grading System

Grade	Defined as
−3	Very hypotonic
−2	Moderately hypotonic
−1	Mildly hypotonic
0	Normal tone
+1	Mildly hypertonic
+2	Moderately hypertonic
+3	Very hypertonic

The two studies in which the RTS was first published are often cited to support the interrater reliability of assessment using this scale.^8,11 The earlier study used the RTS to assess women in three clinical groups: vaginismus, vulvar vestibulitis syndrome (VVS), and a control.¹¹ This study reported an average intercorrelation (statistical approach not reported) of 0.61 between the scores of two physiotherapists for palpation of the superficial PF muscles and of 0.69 between their scores for palpation of the deep muscles, but it did not report on the reliability of the scoring. The later study,⁸ which reassessed the same data but focused on the VVS and control groups, also did not report on the reliability of the RTS scoring. It reported very high chance-corrected agreement (κ = 0.824) between the two physiotherapists for grouping participants on the basis of pathology; however, this agreement was based on a complete examination of the PF, for which assessment of muscle tone represents only one component. This study also reported statistically significant Pearson correlations for the RTS scores, but these do not constitute a measure of interrater reliability.

Interrater reliability is important because it represents the extent to which different clinicians would produce the same findings using a given assessment approach. Good interrater reliability does not demonstrate that any rater is producing an accurate measurement of the characteristic of interest, only that different clinicians tend to produce similar findings. To determine whether assessment findings reflect the characteristic of interest, the validity of the assessment approach must be determined.

High interrater reliability also does not demonstrate that individual clinicians can produce the same assessment findings with repeated testing or detect changes in the characteristic of interest. For this, it is necessary to establish the intrarater reliability, repeatability, and standard error of measurement (and minimal detectable change) of the assessment approach. A detailed discussion of all pertinent measurement properties is beyond the scope of this article; however, determining interrater reliability is a first step in determining the measurement properties of manually assessing intra-vaginal PF muscle tone using the RTS.

Other approaches to assess the musculature of the PF currently have limited clinical applicability and accessibility. Transperineal ultrasound may be used to make indirect inferences about PF muscle tone, and it can be used to assess individual muscle tone in combination with elastography.^10,12 Ultrasound elastography, however, does not measure PF muscle tone at rest,¹² and it requires specialized equipment and a radiologist to interpret the results for clinical use.¹³

Intra-vaginal dynamometry stretches and grades resistance in the anteroposterior or transverse direction with an intravaginal speculum.² Although this approach can be used to measure resistance at rest, it cannot be used to assess tone at a single location because the measured force must be equal in two opposite directions. In addition, PF muscle dynamometers are not currently commercially accessible for clinical use. Manual assessment remains the most accessible means for physiotherapists to assess the PF musculature.

We are aware of one other assessment scale for the PF that involves digital palpation.¹⁴ It assesses the puborectalis muscle, with grades for hypertonicity and hypotonicity, but no grade for normal tone. Moreover, it incorporates levator hiatus size and pain, making it less specific to muscle tone (muscle mass, presence of muscle avulsion, or “personal biometric indices” can influence hiatal dimensions¹⁴) and less generalizable to other PF muscles.

The purpose of this study was to begin to determine whether manually assessing intra-vaginal muscle tone produces reliable findings across different raters. Our primary objective was to determine the interrater reliability of manually assessing intra-vaginal pubococcygeus muscle tone in women, among novice raters, using the RTS. We used an interrater test series by three novice assessors, with the assessors blinded to the participants’ medical history and to the scores of the other assessors. The secondary objective was to assess the correlation between the scores of the novice assessors and those of an expert PF physiotherapist as a cursory means of determining the effect of assessor inexperience on the assessment results. We hypothesized that we would find an interrater reliability coefficient of at least 0.7 (minimally acceptable reliability) for raters with basic training in the assessment of PF muscle tone.¹⁵ We also hypothesized a correlation coefficient of at least 0.7 between the novice and expert scores.¹⁶

Methods

We received ethics approval for this study from the McGill University Faculty of Medicine Institutional Review Board (Study No. A05-B18-19B). All participants provided written informed consent before participating.

Participants

We recruited participants from three physiotherapy clinics in the greater Montreal area and from McGill University. The recruitment strategy aimed to cover the full range of the RTS (shown in Table 1) by recruiting participants with a range of ages, status pertaining to parity, and PF conditions. Potential participants were required to be able to communicate in English or French, but they were excluded if they were aged younger than 18 years, were pregnant or trying to become pregnant, or had unhealed wounds in the pelvic area or any other condition or situation that would prevent an internal vaginal examination. We excluded participants if they had never had any of the following: vaginal penetrative intercourse, an internal gynecological examination, internal vaginal PF physiotherapy, a cervical screening (Pap) test, or insertion of a tampon.

We used three questionnaires to aid in describing the participants’ characteristics: Pelvic Floor Distress Inventory–20 (PFDI–20), Pelvic Floor Impact Questionnaire–7 (PFIQ–7), and the pain domain of the Female Sexual Function Index (FSFI). We selected these questionnaires for their measurement properties,^17,18 use in clinical practice, and availability in both French and English.

To assess interrater reliability on the basis of the individual assessments of the three novice raters, a minimum sample size of 13 participants was deemed necessary, as calculated based on α = 0.05, β = 0.20, a minimally acceptable reliability (ρ₀) of 0.7, and an expected reliability (ρ₁) of 0.9 based on clinical desirability.^19,20 Although a ρ₀ of 0.7 is considered substantial,²¹ the higher value of 0.9 is desirable for instruments used for individual measurements, as is typical of clinical practice, rather than comparisons among groups.¹⁵ For the Spearman rank order correlations, a minimum sample size of 24 participants was deemed necessary as calculated on the basis of α = 0.05, β = 0.20, a minimally acceptable correlation (ρ₀) of 0.7, and an expected correlation (ρ₁) of 0.9 based on clinical desirability. We recruited a larger sample size in an attempt to cover the full range of the RTS.

Focus on pubococcygeus muscle group

This study focused on the pubococcygeus muscle group because of its ease of access during internal vaginal palpation and its implication in several PF pathologies.^22–24 Pubococcygeus tone is assessed by applying a manual pressure, at the 6:00, 9:00, and 3:00 positions on the perineal clock (intra-vaginally, past the puborectalis, as shown in Figure 1), to produce deformation of the muscle fibers.²⁵ The assessments at 3:00 and 9:00 measure left and right pubococcygeus tone, respectively. The 6:00 position is considered important to assess because of its proximity to the pubococcygeus group’s insertion points and its potential influence on the anorectal angle, which is related to global PF tone in the anteroposterior direction.⁸ It must be noted, however, that the 6:00 position includes fibrous influences from the central perineal tendon, rectal thickness, and possible guarding from discomfort of pressure on the rectum.²⁶

Figure 1 .

Diagram of pelvic floor musculature, inferior view, with perineal clock overlay.

Testing protocol

Three graduating physiotherapy students (novices) and one physiotherapist (CB) with more than 25 years of experience in PF physiotherapy (expert) assessed each participant. Each novice had taken a 39-hour university-level PF rehabilitation course and completed an additional 5 hours of practice using the RTS, with primarily young nulliparous women as simulated patients. The novice raters completed all teaching and instruction before the study began and did not receive any feedback from the expert about their assessments of the participants. None of the novices had clinical experience in PF rehabilitation.

We randomized the order of the assessors for each participant, with 15-minute breaks between the assessments to minimize the effects of tissue viscoelasticity on the muscle tone scores. We also asked the participants to refrain from smoking during breaks.²⁷ The assessors were blind to the participants’ past medical history and did not discuss the results of their assessments during the data collection session.

We took all necessary steps to provide a clean and comfortable environment for the participants, including clean sheets and pillowcases, disposable plinth covers, hand washing, gloves, and sterile lubricant gel. Assessors conducted evaluations in closed examination rooms, with a second researcher (not an assessor) present to record the RTS scores. The participants lay supine on the examination plinth, with their head and shoulders supported by pillows and the head of the plinth elevated to allow eye contact between the participant and assessor during the examination.

Assessment of pubococcygeus muscle tone was based on the procedures described by Reissing and colleagues and Dietz and Shek and adapted to assess the global tone of the pubococcygeus muscle group at the 6:00, 9:00, and 3:00 positions (see Figure 1).^8,11,14 For the purposes of this study, we defined muscle tone as the resistance to deformation from a manual force applied approximately perpendicular to the muscle belly, with the participant in a relaxed state. The order of assessment was always 6:00 first, followed by 9:00 and 3:00.

At the start of the assessment, the participant took three deep breaths. The assessor applied flat external pressure with the dorsum of the fingers, progressing from the pubic bone to the pelvic outlet. This pressure accustomed the participant to palpation and facilitated the internal examination while allowing localization of the pelvic outlet. The assessor then asked the participant to perform a PF contraction to confirm whether she could elicit it voluntarily (all participants were able to do so.) After covering the index and middle fingers with the lubricating gel, the assessor placed her index finger at the vaginal opening. The assessor then asked the participant to alternate between contracting and relaxing her PF muscles. During the relaxation phase, the assessor gradually inserted her index finger into the vagina. The assessors used this contract–relax technique to facilitate digital entry and make the insertion more comfortable for the participant while overcoming the PF muscles’ thixotropic effect (a reversible decrease in viscosity after tissue deformation). If the assessor felt that she could insert a second finger, she inserted the middle finger. If two fingers could not be inserted comfortably, the assessment was completed with only one finger (muscle hypertonicity, patient discomfort, or clinician judgment may limit the use of two fingers).^28,29 Relative depth of finger insertion likely differed between assessors (finger length) and participants (vaginal depth).

Once the assessor inserted her finger or fingers past the vaginal vestibule, she assessed the global anteroposterior tone of the pubococcygeus group by applying a postero-inferior pressure at the 6:00 position with the finger or fingers slightly flexed. Slightly flexing the finger may account for the pubococcygeus muscle’s anatomy and help maximize the participant’s comfort by limiting pressure on the vaginal introitus. The assessor then graded the tone of the right and left pubococcygeus muscles at 9:00 and 3:00. After the participant made a slight PF contraction and relaxation to localize the muscle belly, the assessor applied pressure in a latero-postero-inferior direction. For each location, the assessor was free to repeat the palpation, without withdrawing her finger or fingers, to be confident about her assessment. Each assessor documented only one score, however, for each position (6:00, 9:00, and 3:00), as would be done in a clinical chart, totaling three scores per assessment.

Data and statistical analysis

We used IBM SPSS Statistics (Version 23; IBM Corporation, Armonk, NY) and MATLAB (Mathworks, Natick, MA) for statistical analyses, with an α level of 0.05 and a b of 0.20.

Interrater reliability

We produced intra-class correlation coefficient (ICC) estimates, and their 95% CIs, for the RTS scores from the three novice assessors using a two-way random single-measures absolute agreement ICC. Although the RTS is an ordinal scale, Norman and Streiner suggested using parametric statistics with 7-point ordinal scales, provided the data are normally distributed.³⁰ Although the weighted κ is often the statistic of choice for ordinal data, the ICC can accommodate three raters.^30,31

We conducted Shapiro–Wilk tests to ensure that the data were normally distributed. We then performed three reliability analyses for the tone measurements, taken at the three locations on the pubococcygeus muscle (6:00, 9:00, and 3:00), producing three reliability coefficients.

Order of assessments

We used Kruskal–Wallis tests, using χ² approximation, to determine whether the order of testing had significantly affected the RTS scores. We compared the scores among the first, second, third, and fourth scores for each participant at each of the three locations on the pubococcygeus muscle (6:00, 9:00, and 3:00).

Correlations

We used Spearman rank correlation analysis to assess the correlation of the scores between the novice raters and the expert rater.¹⁶ We conducted three analyses, comparing the scores of the expert evaluator and those of each novice rater, including all three measurements taken by each one.

Results

Participants

We recruited a total of 31 female participants. Table 2 provides demographic information on age, parity, and gravidity, and Table 3 provides questionnaire scores. Each of the three subscales of the PFIQ–7 and PFDI–20 is scored on a scale ranging from 0 (least impact) to 100 (greatest adverse effect), with an overall summary score ranging from 0 to 300.^17,18 The FSFI pain domain has a cumulative score ranging from 0 to 15; higher scores indicate more pain.¹⁵

Table 2 .

Participants’ Characteristics

Characteristic	Mean (SD)	Range, min–max
Age, y	37.8 (14.8)	20–66
Parity, no. of pregnancies	1.0 (1.2)	0–3
No. of births	0.9 (1.2)	0–3

Table 3 .

Questionnaire Scores

Questionnaire	Quartile 1	Median	Quartile 3	Range, min–max
PFIQ-7
Summary score	0	0	10	0–133
Bladder or urine symptoms	0	0	5	0–57
Bowel or rectum symptoms	0	0	0	0–67
Vagina or pelvis symptoms	0	0	0	0–24
FSFI pain domain	0	5	6	0–6
PFDI–20
Summary score	6	23	48	0–190
POPDI-6	0	4	8	0–54
CRADI–8	0	6	19	0–81
UDI–6	0	8	29	0–67

PFIQ–7 = Pelvic Floor Impact Questionnaire–7; FSFI = Female Sexual Function Index; PFDI–20 = Pelvic Floor Distress Inventory–20; POPDI–6 = Pelvic Organ Prolapse Distress Inventory 6; CRADI–8 = Colorectal-Anal Distress Inventory 8; UDI–6 = Urinary Distress Inventory–6.

Manual assessment of muscle tone

Figure 2 illustrates the distribution of RTS scores for the three novice raters and one expert rater. RTS scores were unevenly distributed, with no scores of 3 (very hypertonic) and a limited number of –3 scores (very hypotonic) from two of the four raters.

Figure 2 .

Frequency of RTS scores for the four assessors: (a) 6:00, (b) 9:00, and (c) 3:00.

Interrater reliability

Data distribution, at all three test positions, did not deviate significantly from a normal distribution: 6:00, Shapiro–Wilk coefficient W = 0.969 (p = 0.871); 3:00, W = 0.854 (p = 0.171); and 9:00, W = 0.899 (p = 0.404).

The interrater reliability among the three novice raters was highest for the 6:00 position (0.523; 95% CI: 0.315, 0.709; p = 0.968) and lower for the 3:00 (0.346; 95% CI: 0.129, 0.569; p = 1.000) and 9:00 (0.274; 95% CI: 0.055, 0.512; p = 1.000) positions. We consider these values low to moderate,³² with the lower bounds of the CI well below our stated minimally acceptable reliability of 0.70.

Order of assessments

The Kruskal–Wallis χ² approximation did not reach significance for any of the three testing positions, indicating that the testing order did not affect the RTS scores: 6:00, 2.783 (p = 0.426); 3:00, 0.803 (p = 0.849); and 9:00, 1.219 (p = 0.749).

Correlations

The correlations of the RTS scores between the three novices and the expert rater were also low to moderate,³³ with r = 0.580 (95% CI: 0.382, 0.782; p = 0.953), r = 0.342 (95% CI: 0.139, 0.461; p = 1.000), and r = 0.320 (95% CI: 0.124, 0.526; p = 1.000). The lower bounds of the confidence interval, for all correlations, were well below our stated minimally acceptable correlation of 0.70.

Discussion

The interrater reliability among the novice raters in manually assessing pubococcygeus muscle tone in women, scored using the RTS, was well below the expected reliability value of 0.9 that would have made this assessment suitable for clinical use as a stand-alone test, and it was also below the minimal acceptable reliability of 0.7. Moreover, we found only low to moderate correlations between the RTS scores of the novice raters and those of the expert PF physiotherapist.

Factors affecting reliability

The most obvious factor that may have affected the reliability of the PF muscle tone scores in this study is the inexperience of the novice assessors, who were students in the final year of a master’s programme in physiotherapy. At the time of the study, their experience with assessing PF muscle tone had been limited to a 39-hour university course on PF physiotherapy, which included 9 hours of practical assessment with classmates as simulated patients and 5 additional hours of practice with the RTS scoring, all led by the expert assessor (CB). Thus, the novices’ experience in PF assessment was largely limited to young, nulliparous women. This may have altered what the novices viewed as normal tone, limited their view of the range of muscle tone that may be encountered clinically, or both. The novices’ scoring may also have been affected by anatomical variations in the depth and thickness of the PF tissues and by conditions such as vaginal stenosis that they had not experienced in their training.

Another factor that may have affected the study findings was our limited success in recruiting participants with tone scores at the ends of the RTS range (very hypertonic or very hypotonic; see Figure 2). The earliest study using the RTS,¹¹ for which a large number of women with conditions linked to PF hypertonicity (VVS and vaginismus) had been recruited, produced correlations as high as 0.69 for tone scores between experienced physiotherapists for the deep muscle layer of the PF (statistical method not reported). However, the later reassessment of these data,⁸ which included only those women with VVS and the pain-free controls, saw the Pearson correlation coefficients between the raters drop to 0.319–0.514 for the deep PF muscles. It is possible, therefore, that greater consistency in scoring between assessors may be found at the most hypertonic end (and, arguably, the most hypotonic end) of the RTS.

Another plausible reason for the low interrater reliability in our data is that many of the factors that affect muscle tone (tissue viscoelasticity, electrogenic contraction) may change with repeated assessment. Although our testing methodology attempted to minimize this, it is impossible to fully control this variability.

The passive viscoelastic resistance of muscle is derived from the extensibility of actin and myosin filaments and their cross-bridges;^34,35 of non-contractile proteins within the sarcomeres;³⁶ and of intramuscular (within the muscle belly), intermuscular (between the adjacent muscles), and extramuscular (between the muscle and other adjacent structures) connective tissues, including pathological adhesions and scarring.^2,37 Muscles also demonstrate thixotropy, a reversible decrease in viscosity once movement has been established.³⁸ This is evident in muscles by increased resistance to movement after a period of inactivity and reduced resistance after a few active or passive loading cycles.³⁹ We attempted to minimize the impact of these viscoelastic properties by providing 15-minute breaks between assessments and by having the participants perform alternating contractions of the PF muscles during the testing procedure. These mitigating techniques may not have been adequate to stabilize the viscoelastic properties of the muscles.

Activating the contractile elements of the muscles can also contribute to PF muscle tone. This can occur in normal (voluntary or reflexive) electrogenic contraction, abnormal electrogenic contraction, and endogenous contracture (contraction of the sarcomeres in the absence of α-motor neuron activity).^40,41 Although we attempted to assess the participants in a relaxed state, it is possible that some variability in muscle activation may have been present during the repeated testing. Two participants reported a slight increase in discomfort as the evaluations proceeded, and their scores reflected increasing hypertonicity. Conversely, pubococcygeus tone may have decreased for some participants as they became more familiar or comfortable with the testing procedure.

Implications for manual clinical assessment of pelvic floor muscle tone

Our data indicate that manually assessing PF muscle tone is not adequately reliable as a stand-alone assessment technique for novice raters. It is important to note, however, that the evaluation conducted in the current study was only a small component of a complete physiotherapy assessment of the PF musculature. The delicate nature of the assessments performed, and the need for repeated assessments to determine reliability, limited our testing protocol.

A complete physiotherapy PF assessment is likely to involve assessing muscle tone at eight or more locations,⁹ as opposed to the three locations tested in this study. Physiotherapists also commonly assess muscle strength and post-contractile relaxation because each provides different information about the condition of the PF muscles.

The interrater reliability of a complete PF muscle assessment is likely to be much better than that of any one individual assessment component, as evidenced by the very high agreement between the physiotherapists in the study by Reissing and colleagues for differentiating women on the basis of PF pathology (κ = 0.824),⁸ despite low to moderate correlations between the assessors for the RTS scores. Other clinical assessment approaches have similar findings (improved reliability based on composite scores of multiple tests) – for example, assessing motion palpation and using provocation tests for the sacroiliac joint.⁴²

Further work is required to determine the degree to which assessor inexperience, patient population, and the nature of the assessment itself are responsible for the low interrater reliability in the current study. Work is also needed to determine the validity of manually assessing muscle tone relative to quantitative instrumented approaches (although current instrumentation has limitations that prevent direct comparison), the link between PF muscle tone and patient symptomatology, and the interrater reliability of a complete physiotherapy PF assessment, of which muscle tone assessment is only one component. In addition, it is important that repeated assessment by the same clinician produce reliable results, for testing both within the same session (e.g., to determine the short-term effects of an intervention) and between sessions (e.g., to track a patient’s progress over time).

This study had several limitations. First, our attempts to recruit women with PF conditions covering the full range of the RTS were not successful (see Figure 2). Second, our inability to recruit participants at the extreme ends of the scale may have been partly due to the time constraints associated with this student-led study, but it may have also been due to our decision, for ethical reasons, to exclude women with excessive pain or intolerance to internal palpation. The latter may have eliminated participants at the extreme hypertonic end of the scale.

Third, because of the nature of the PF assessment, the assessors were not blinded to all participant characteristics that may have been associated with their PF muscle tone.^43,44 The assessors were blinded to gravidity, parity, PF condition, and the exact age of the participants. Despite this, protective reactions and nervousness were observable, which may have introduced some bias into the RTS scoring. Allowing for interaction between the assessor and the patient, however, facilitates the generalizability of our findings to the clinical setting.

Next, our testing protocol allowed an assessor to repeat a palpation, without withdrawing her finger or fingers. We recorded only one score for each location, however, as we would in a clinical chart. The reason for this was to assess interrater reliability in a pragmatic manner, but it precludes using our data to estimate within-session intrarater reliability.

Finally, we assessed tone only for the pubococcygeus muscle group, so our findings may not be generalizable to other PF muscles. Given that correlations between RTS scores in previous studies did not vary greatly for different muscle sites,^8,11 however, it is unlikely that muscle location greatly affects interrater reliability.

Conclusion

We found low to moderate interrater reliability among the novice assessors for manually assessing intra-vaginal pubococcygeus tone in women using RTS scoring. Novice RTS scores also showed low to moderate correlations with those of an expert PF physiotherapist. These data indicate that physiotherapists should not use this approach to assessing PF muscle tone as a stand-alone test to guide clinical decision making, at least when the physiotherapist has limited clinical experience.

Key Messages

What is already known on this topic

Pelvic floor (PF) physiotherapy is a first-line intervention to address various PF conditions. Tone, defined as resistance to deformation, is linked to multiple PF pathologies and is thus an essential component of a PF examination. The Reissing tone scale (RTS) is an accessible and easy-to-use manual scale to assess PF muscle tone, and it is widely used clinically. The interrater reliability of RTS scoring, for manually assessing PF muscle tone, has not been established.

What this study adds

Intra-vaginal manual assessment of pubococcygeus muscle tone in women, scored using the RTS, produced low to moderate interrater reliability among three graduating physiotherapy students. Novice physiotherapists should not use this assessment approach as a stand-alone test to guide clinical decision making.