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Letter to the editor. RE: A field-based approach for examining bicycle seat design effects on seat pressure and perceived stability (Bressel et. al., Appl Ergon 2009 May; 40(3):472-476).
Lowe BD; Schrader SM; Breitenstein MJ
Appl Ergon 2010 Jan; 41(1):173-174
The recent paper by Bressel et al. (Applied Ergonomics vol 40, issue 3) comparing interface pressure distributions of traditional and full cut-away bicycle saddles (seats) reports that "...optimal anterior seat pressure and perceived seat stability appear to be inversely related" (p. 5). In other words, their subjects reported lower perceptions of bicycle stability with the full cut away or no-nose saddle, which was associated with significantly less anterior interface pressure - pressure that corresponds spatially to the perineal area of the cyclist. Bressel et al. conclude that selection of a bicycle saddle to reduce anterior pressure should not be informed by the saddle interface pressure profile alone. We are in agreement with Bressel and his colleagues that multiple factors should inform the selection of a bicycle saddle and that use of a full cut-away bicycle saddle (saddle without the narrow protruding nose) is initially accompanied by a perception of decreased stability on the bicycle. However, the more relevant question about the full cut-away saddle, in our view, is whether cyclists can adapt to this saddle to safely accomplish their cycling activity. We question a premise that perceptions of bicycle stability assessed after use of the saddle for only eight minutes can reliably predict successful adaptation to the bicycle saddle. We are concerned that inferences about perceived bicycle stability, based on such a short duration test session, may lead bicyclists looking to alleviate harmful perineal/groin pressure to prematurely reject the no-nose, or full cut-away, saddle designs. Significant scientific evidence implicates the use of a nosed bicycle saddle with elevated risk for erectile dysfunction (Huang et al., 2005). The traditional racing/sport bicycle saddle with a narrow protruding nose is associated with increased pressure in the perineum ([Lowe et al., 2004] and [Schrader et al., 2008]), decreased transcutaneous penile oxygen pressure (Schwarzer et al., 2002), decreased penile blood flow (Munarriz et al., 2005 R. Munarriz, V. Huang, J. Uberoi, S. Maitland, T. Payton and I. Goldstein, Only the nose knows: penile hemodynamic study of the perineum-saddle interface in men with erectile dysfunction utilizing bicycle saddles and seats with and without nose extensions, Journal of Sexual Medicine 2 (2005), pp. 612-619. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (10)Munarriz et al., 2005), and occlusion in the cavernosa (Bressel et al., 2007). The full cut-away, or no-nose, saddle is an intervention that has been demonstrated in independent studies to create less compression of the soft tissues in the perineal region, less restriction of penile blood flow, and less reduction in transcutaneous penile oxygen pressure. Given the effectiveness of no-nose saddles at reducing these risks to sexual function associated with the bicycle saddle, we believe it is critical to comprehensively investigate other aspects of no-nose saddle effectiveness, including perceptions of bicycle stability and general acceptance by users. In a recent prospective study (Schrader et al., 2008) 90 police bicycle patrol officers from five different U.S. metropolitan police departments were given a no-nose (i.e., full cut-away) saddle to try for a six-month study period. At the six-month follow-up only three of these individuals had reverted to using their previous traditional (nosed) saddle. We interpreted this finding as evidence that cyclists engaged in bicycling similar to that of police patrol work can successfully adapt to the full cut-away saddle, if they are so motivated. Several of these police officers commented that it took some time to adapt to cycling with the no-nose saddle (see Prescott, 2007). The Bressel et al. study soundly confirms what anecdotal reports have suggested - adaptation to cycling with a full cut-away saddle is not immediate. However, it is our opinion that users looking to reduce exposure to perineal pressure from their bicycle saddle should not be deterred by perceptions of instability in the first few minutes of use of a no-nose saddle. The Bressel et al. study raises an important question about the duration of an evaluation period for ergonomic interventions and how this affects user acceptance. Recent data on no-nose bicycle saddles suggests that users who are motivated to reduce a source of discomfort, and possibly more severe symptoms, are willing to spend more than eight minutes adapting to an intervention that reduces the risk factor to which they are exposed. Disclaimer: The opinions expressed in this letter are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.
Bicycles; Equipment-design; Ergonomics; Exposure-assessment; Exposure-levels; Exposure-methods; Muscle-function; Muscle-physiology; Musculoskeletal-system-disorders; Occupational-exposure; Police-officers
Brian D. Lowe, CDC, DART, National Institute for Occupational Safety and Health, 4676 Columbia Parkway, MS C-24, Cincinnati, OH 45226
Issue of Publication
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division