The Effect of Ankle Position on Pelvic Floor Muscle Contraction Activity in Women

Chen HL, Lin YC, Chien WJ, Huang WC, Lin HY & Chen PL. The Journal of Urology. 2009 March; 181: 1217-1223

 

Women’s Health Distance Journal Club 1/08/2014

Jacqueline M York, PT, DPT, CHES

Purpose: To examine the effects of ankle position on PFM activity and MVC.

Participants: 31 women between 26 to 60 (30-56 later in article?) years old were recruited from teaching hospital in northern Taiwan. One participant experienced 5 pregnancies and another 3, however type of delivery not specified. Parity of other participants was not directly described. It was not described whether or not participants were continent.

Inclusion Criteria: Women who could correctly perform PFM contraction and rise up on toes

Exclusion Criteria: Pregnant, Previous gynecologic surgery or any foot/ankle joint disease/disorder

Standardized protocol:  Subjects placed separately in private rooms. Protocol was explained to subject, consent signed, PFM contraction taught and confirmed via EMG biofeedback with intra-vaginal probe. Subjects contract PFM in eight different positions. Order of positioning was chosen at random via drawing from a box.  Subjects performed three PFM contractions in each position in a pre-defined, randomized order. A ten second rest was allowed after each contraction and a three-minute rest was allowed between each position. PFM contractions were recorded in four active and four passive ankle positions. Active positions included dorsiflexion and plantar flexion with and without arms raised. Passive positions included plantar flexion and dorsiflexion on 2.5 cm and 4.5 cm wedge. The subjects visualized the contraction on a computer screen and the FemiScan equipment recorded maximum and mean MVC amplitude for each contraction.

Study Design: two-way design with two repeated measures; RCT

·         “Repeated measures design- One group of subjects tested under all conditions and each subject acts as his/her own control. Two-way design due to study involving more than one independent variable”  (1)

·         Independent Variables- Foot position and active vs. passive

Statistical analysis:  Non-parametric statistical tests were used, as data was not normally distributed. Wilcox sign ranked test completed with level significance at 0.05. Test used was appropriate for study design (1). Wilcox Sign ranks tests analogous to paired T-tests, it examines direction of difference and relative amount of difference (1).

Results: All active positions displayed higher MVC of PFM than horizontal standing. Statistically significant differences were only demonstrated in the PFAU position when compared to all other positions except 4.5 cm DF. Also, clinical significance was achieved when comparing active vs passive PF.

·         Chen et al (2005)- Found that the passive dorsiflexed position increase PFM activity more than horizontal or plantar flexed position when in static upright standing in women with SUI. They attributed this to the anterior pelvic tilt created when ankles in DF.  (2)

·         Cerruto et al (2012)- Looked at PFM MVC in women with SUI. Also, found higher PFM activity in dorsiflexion position, however lower MVC of PFM. In this study a slight plantar flexed position improved PFM MVC via sEMG with patient standing on adjustable platform. (3)

·         Both attributed PFM activity to pelvic tilt caused by ankle position.

Limitations:

·         Small sample size (31)

·         Sample of convenience

·         Subjects and examiners were not blinded

·         Teaching/learning effect (Participants viewed contractions via computer screen)

·         Fatigue effect also possible

·         Study did not specify whether or not subjects were continent

Take Home:  Based on current evidence, it is unclear what the optimal ankle position for PFM MVC. The evidence seems to support the plantar flexed position of the ankle for MVC of PFM, particularly if it is active with muscle co-contraction, however more studies need to be conducted in this area in order to determine clinical significance and application to treatment of SUI.

Implications/possible discussion:

·         Only 3 studies to date exploring effect of ankle position of PFM activity and MVC. There seems to be some clinical significance to ankle position as it affects PFM activity.  Additional research to be done studying effects of positioning and muscle co-activation on optimal PFM activation and MVC.

·         Authors suggest PFAU position may be included in treatment for SUI to improve efficacy PFM exercise.

o   Does anyone use any similar positions in treatment session for SUI?

o   How many already incorporate PFM contraction in active positions and/or with muscle co-activation for overload into treatment plan for SUI?

·         In the study women were able to correctly contract PFM. Once correct contraction is confirmed, is it possible that increasing MVC of PFM utilizing co-contraction could improve hypertrophy effects via improved PFM contraction?

Additional Discussion points from meeting:

·         The article included an unnecessary paragraph in the introduction about EMG which was not useful

·         The article did not study passive positions with arms raised versus active position. Could the observed MVC be due to overflow?

·         It would be useful to know what the abdominals are doing in all of these positions as well as the PFM.

·         Additional abstract by Maher et al. in Journal of Women’s Health Physical Therapy discussed ankle position and PFM activity as well. This abstract discussed a more symmetrical contraction observed.

·         Additional previous studies discussed regarding ankle dorsiflexion and Tra contraction as well as pelvic tilt on PFM activity- authors?

·         Could the various positions change in COG due to ankle position cause an increased overall muscle co-activation and account for increased PFM activity and MVC?

·         Both PF and DF result in anterior pelvic tilt due to over compensation 

·         TrA activity is increased in anterior tilt

·         Regarding the idea of overflow, do we want it or should we continue to avoid with PFM training? It could be useful with regard to functional tasks. Perhaps there is a point in the POC where isolation vs overflow and co-activation may be more appropriate with SUI.

·         We need more research and better designed studies.

References

1.      Portney LG,Watkins MP. Foundation of Clinical Research: Applications to Practice 3^rd edition. Upper Saddle River, New Jersey: Pearson Education; 2009.

2.      Chen CH, Huang MH, Chen TW, Weng MC, Lee CL, Wang GJ. Relationship between Ankle Position and Pelvic Floor Muscle activation in Females Stress Urinary incontinence. Urology 2005; 66: 288–292

3.      Cerruto MA, Vedovi E, Mantovani W, D’Elia C, Artibani W. Effects of Ankle Position on Pevic Floor Muscle electromyographic Activity in Female Stress Urinary Incontinence: Preliminary results from a Pilot Study. Archivio Italiano di Urologia e Andrologia 2012; 84(4)