Evaluation of pelvic floor muscle activity during running in continent and incontinent women: An exploratory study

Aims:
Impact activities like running are known to elicit symptoms of stress urinary
incontinence (SUI). The aim of this study was to investigate and compare pelvic
floor muscle activity in continent and SUI women during running at three different
speeds and thereby elucidate contraction characteristics of the pelvic floor during
impact.

Methods:
Surface electromyographic (EMG) activity from the pelvic floor muscles
during running on a treadmill was recorded with a tripolar vaginal probe. EMG was
measured during 10 s at the speeds 7, 11, and 15 km/h. Data from 30 ms before to
150 ms after heel-strike were parameterised to time intervals of 30 ms. The
reference value set as 100% for EMG normalisation was calculated as the mean of
the peak values of two maximum voluntary contractions.

Results:
No statistically significant differences between continent and incontinent
subjects could be found for the EMG values for all time intervals. Mean EMG preactivity
and reflex activity increased significantly with speed (P < 0.05). Mean
EMGactivity during running was significantly above PFM onset activation. Values
in women with SUI exceeded 100 %MVC for all time intervals at the highest speed
of 15 km/h.

Conclusions:
Running appears to trigger pre-activation before and reflex-activation
after heel-strike and should therefore not only be regarded with caution due to its
SUI related effects. Running training stimuli may serve as a beneficial complement
to a PFM training rationale, leading to reflex activity of the pelvic floor muscles,
when used in sense of power training methodology.