Involuntary reflexive pelvic floor muscle training in addition to standard training versus standard training alone for women with stress urinary incontinence: study protocol for a randomized controlled trial

Background Pelvic floor muscle training is effective and recommended as first-line therapy for female patients with stress urinary incontinence. However, standard pelvic floor physiotherapy concentrates on voluntary contractions even though the situations provoking stress urinary incontinence (for example, sneezing, coughing, running) require involuntary fast reflexive pelvic floor muscle contractions. Training procedures for involuntary reflexive muscle contractions are widely implemented in rehabilitation and sports but not yet in pelvic floor rehabilitation. Therefore, the research group developed a training protocol including standard physiotherapy and in addition focused on involuntary reflexive pelvic floor muscle contractions. Methods/design The aim of the planned study is to compare this newly developed physiotherapy program (experimental group) and the standard physiotherapy program (control group) regarding their effect on stress urinary incontinence. The working hypothesis is that the experimental group focusing on involuntary reflexive muscle contractions will have a higher improvement of continence measured by the International Consultation on Incontinence Modular Questionnaire Urinary Incontinence (short form), and — regarding secondary and tertiary outcomes — higher pelvic floor muscle activity during stress urinary incontinence provoking activities, better pad-test results, higher quality of life scores (International Consultation on Incontinence Modular Questionnaire) and higher intravaginal muscle strength (digitally tested) from before to after the intervention phase. This study is designed as a prospective, triple-blinded (participant, investigator, outcome assessor), randomized controlled trial with two physiotherapy intervention groups with a 6-month follow-up including 48 stress urinary incontinent women per group. For both groups the intervention will last 16 weeks and will include 9 personal physiotherapy consultations and 78 short home training sessions (weeks 1–5 3x/week, 3x/day; weeks 6–16 3x/week, 1x/day). Thereafter both groups will continue with home training sessions (3x/week, 1x/day) until the 6-month follow-up. To compare the primary outcome, International Consultation on Incontinence Modular Questionnaire (short form) between and within the two groups at ten time points (before intervention, physiotherapy sessions 2–9, after intervention) ANOVA models for longitudinal data will be applied. Discussion This study closes a gap, as involuntary reflexive pelvic floor muscle training has not yet been included in stress urinary incontinence physiotherapy, and if shown successful could be implemented in clinical practice immediately. Trial registration NCT02318251; 4 December 2014 First patient randomized: 11 March 2015 Electronic supplementary material The online version of this article (doi:10.1186/s13063-015-1051-0) contains supplementary material, which is available to authorized users.


Introduction
To date, the focus of research on pelvic floor muscle (PFM) function has been on the concentric and isometric muscle action that leads to the lift and squeeze but so far no light has been shed on the eccentric or eccentric-concentric type of contraction and the related involuntary or reflexive power. "Power" has to be interpreted as mechanical power (P(t) = F x v  power equals force times velocity) in the sense of rate of force development in the here described context of training.
It can be assumed that the impact loading on the PFM evoked by coughing, running, jumping or any abrupt rise in intra-abdominal pressure provokes involuntary muscle reactivity. Based on the literature review presented in the study protocol the main deficit of an insufficient and incontinent PFM is the lower maximal force and the lower power compared to sufficient PFM. Consequently, the special attribute of the standardized therapy plan for the experimental group introduced here aims at power with voluntary and in contrast to the control group as well as involuntary reactive strength with reflexive PFM contractions as a characteristic of a physiological unconscious and not perceived functioning of PFM during daily life activities or activities with short but intensive impacts (jumps, running, coughing etc.).
Although conventional therapy programs finally also focus on the power, however, fast voluntary PFM contractions are applied only. That means this program of the control group is carried out without the above mentioned involuntary reactive contractions.
Both programs are based on the latest position stand paper of the American College of Sports Medicine (ACSM) [1,2], PFM motor learning concepts [3,4], and strength training concepts [1,2,[5][6][7]. However, even in these references the training methods vary within a certain range (e.g. repetitions: 8-12; rest intervals: 1-2 minutes, velocity: slow to moderate, etc.). This lack in standardization of training regimens is well known [8]. Therefore, within in these methodological ranges training programs presented her are precisely standardized for the control and experimental group separately and following the references and training principles and methods.
The planned progression of training for strength, power and hypertrophy is shown in Table 1.

Respected training principles
Training procedures for motor learning, strength, hypertrophy and power training phases will follow the below mentioned training principles for both groups.
Variation / periodization. Changes of a therapy program over time allow for the training stimulus remain to be effective and challenging. The here used classical periodization is characterized by the intention to carry out the fundamental aspects (motor learning, strength, hypertrophy, power) to prepare distinct abilities.
[1] Table 1 shows a 16 weeks lasting training program with a total number of 78 training sessions with additional 9 personal consultations (= physiotherapy sessions) for both groups. Motor learning and strength and hypertrophy phases are comparable for both groups, however the main difference between the programs is the applied type of muscle action (control group (CON): isometric, concentric; experimental group (EXP): isometric, concentric, eccentric und eccentric-concentric) and speed of movement (CON: voluntary slow to moderate (to explosive) [3,5]; EXP: explosive, reactive, reflexive; for details see tables for weekly training below).
Muscle action and velocity of muscle action. All training adaptations are "specific" to the stimulus applied. The relevant factors are the muscle actions involved (CON: concentric; EXP: concentric, eccentric-concentric), the speed of movement (CON: slowmoderatequick; EXP: explosivereactive) and the muscle groups trained (CON: PFM; EXP: PFM). The supra-maximal eccentric actions are known to produce an additional benefit in terms of force generation compared to concentric or isometric contractions.
The recommendations of the ACSM [1] do not bring up the idea of involuntary eccentricconcentric, reactive strength training with maximal explosive contraction velocities as Güllich and Schmidtbleicher [7] propose. However, ACSM recommends jumps with fast repetition velocity for maximal progression in jump performance. This idea will be introduced into the training program of the experimental group aiming on the reactive activation of PFM. The program of the control group uses slow to moderate to quick voluntary contractions instead. Loads during jumps and running are described as a trigger for incontinence.
Loading. Due to the fact that no external weights are possible it is not possible to carry out a 1 repetition maximum (1RM) like recommended. Therefore it is quite difficult to describe the loading of PFM strength training. Voluntary (and involuntary) contractions of the PFM will be performed in relation to maximal voluntary contraction (MVC). The patients will be familiarized with this maximal loading and submaximal loads will be estimated and performed in relation to 100%MVC. [1] Volume. One to three sets per exercise are recommended to be used by novice individuals. For progression long term studies indicated multiple sets and a systematic variation of volume over time. [1] Exercise selection. This training program focusses on the voluntary and involuntary PFM contraction. Involuntary PFM contraction will be performed by running or jumping on the spot. [1] Rest periods. The range of rest periods will be 30 seconds to 120 seconds because the exercises used are with low complexity. [1] Frequency. Besides 9 personal physiotherapy consultations both groups will train 3 times a week (week 1-5 3x/week, 3x/day; week 6-16 3x/week, 1x/day = 78 home training sessions) for 16 weeks to be comparable in training frequency. [1] The basic therapy will be performed in both groups equally during the 9 intended physiotherapy sessions. Basic therapy represents the usual physiotherapy session contents in the presence of a physiotherapist and patient. Both groups will receive the basic therapy during 9 physiotherapy sessions which homogeneously distributed take place in the weeks 1, 2, 4, 6, 8, 10, 12, 14, and 16.
First, the home exercises and training methods will be instructed, supervised and controlled by the physiotherapist at the 9 physiotherapy sessions only, which is best practice and sufficient [9]. This procedure should also grant a high and sustained adherence over time [10,11].
Third, life style interventions for pelvic floor dysfunction will additionally be given during the therapy and follow-up period following the recommendations of Chiarelli [23].

Therapy plan
According to the above discussed training principles and basic therapy a detailed and standardized training program is carried out in the following for each week of training including a short description of the related physiotherapy session 1-9 (aims, basic therapy) and the separate home exercise program for each group with aims of training, exercises used, relevant muscle action type and contraction velocity, description of loading, number of repetitions, volume, duration of rest, training frequency per day/week, and body position applied. st week of exercise program 1 st Physiotherapy session Aims: The patient is able to perform a correct isolated maximal voluntary pelvic floor muscle (PFM) contraction (squeeze around pelvic openings and inward (cranial) lift [24,25]. Basic therapy: Make an anamnesis and explain the function of the pelvic floor [13][14][15]. Teach isolated PFM contractions [16] and the home exercise program corresponding to the randomized groups (see below). Aims: Control and improvement of the home exercise program. The patient is able to contract isolated transversus abdominus muscle [22,26]. Basic therapy: Training of voluntary contraction of lower abdominal muscles as the patient would like to zip too tight pants. Important: no movements within the spine region and breathing should be performed. Teach the home exercise program corresponding to the randomized groups (see below).

months follow-up
After the intervention phase the patients receive an information sheet and instruction about the necessary and following home exercise program between the end of therapy and the 6 months followup. Generally patients should continue performing PFM exercises for years after completing their physiotherapy education sessions [27].
Both groups continue their training as described below

Further information
Take care while you are lifting up something: Don't forget the pre-contraction of the pelvic floor muscle! Drink about 1½ liter per day and prefer water. 5-6x micturition per day and 0-1x per night are okay. Be mindful on the correct posture while sitting, standing and lifting.