Objective: To identify a seat pressure threshold that corresponds to significant compression of the perineum.
Design: Quasiexperimental crossover.
Setting: Radiology department of a hospital.
Participants: A convenience sample of 6 male recreational cyclists.
Intervention: Compression of the corpus spongiosum and corpora cavernosa of the perineum without bicycle seat pressure (0) and at 10%, 40%, and 80% of the mean bicycling pressure was assessed using MRI. Seat pressure was applied using a custom loading device designed to replicate seat pressure recorded during stationary bicycling.
Outcome Measure: Diameter measurements of the cavernous spaces at the point of peak compression.
Results: The mean diameter values for the corpus spongiosum in the unloaded and 10% of load conditions were 105% and 172% greater than the 40% and 80% loaded conditions, respectively (P = 0.002-0.004). Similarly, the corpora cavernosa values for the unloaded and 10% of max load conditions were 115% and 175% greater than the 40% and 80% loaded conditions, respectively (P = 0.001-0.0001).
Conclusions: From our data it may be suggested that substantial compression of the perineal cavernous spaces occurs with total seat pressure values of less than 40% of typical seat loads.