Biomechanical Comparison of Shorts With Different Pads

An intensive use of the bicycle may increase the risk of erectile dysfunction and the compression of the perineal area has been showed to be a major mechanism leading to sexual alterations compromising the quality of life. Manufacturers claim that pads contribute to increase cyclists perineal protection ensuring a high level of comfort. To investigate the influence of various cycling pads with regard to perineal protection and level of comfort. Nine club road cyclists rode 20 min on a drum simulator, located at the Nutrition and Exercise Physiology Laboratory, at a constant speed and gear ratio wearing the shorts with 3 cycling pads of different design and thickness: basic (BAS), intermediate (INT), and endurance (END). Kinematics and pressure data were recorded at min 5, 15, and 20 of the test using a motion capture system and a pressure sensor mat. The variables of interest were: 3-dimensional pelvis excursions, peak pressure, mean pressure, and vertical force. The comfort level was assessed with a ranking order based on the subjects’ perception after the 20-min trials and measuring the vertical ground reaction force under the anterior wheel as well as the length of the center of pressure (COP) trajectory on the saddle. Results showed that the vertical force and the average value of mean pressure on the saddle significantly decreased during the 20-min period of testing for BAS and END. Mean peak pressure on the corresponding perineal cyclist area significantly increased only for BAS during the 20min period. Interestingly objective comfort indexes measured did not match cyclists subjective comfort evaluation. The lower capacity of BAS to reduce the peak pressure on the corresponding perineal area after 20 min of testing, together with its positive comfort evaluation, suggest that a balance between protection and perceived comfort should be taken into account in the choice of the pad. Hence, the quantitative approach of objective comfort indexes introduced in this study could be helpful for manufacturers in the rone, PhD, Carlo R and Antonio Paoli, MD Abbreviations: BAS = basic, COP = center of pressure, END = endurance, INT = intermediate, TDC = top dead centers, vGRF = vertical component of the ground reaction force. INTRODUCTION A n intensive use of the bicycle can lead to nontraumatic injuries as reported by Dettori and Norvell. In the last few years scientific literature focused on the overuse injuries affecting the genitourinary tract because of their effect on the reduction of cyclists quality of life: mechanical causes of these injuries and countermeasures to reduce the problem are the main topics of researchers. Dettori et al examined the relationship between bicycle characteristics and the occurrence of erectile dysfunction in 463 cyclists who completed a cycling event of at least 320 km. Results showed a cumulative incidence of erectile dysfunction after the ride of 4.2% and of 1.8% 1 week and 1 month after the event. Leibovitch and Mor reported in a review that the most common bicycling associated urogenital problems are nerve entrapment syndromes presenting as genitalia numbness, which is reported in 50% to 91% of the cyclists, followed by erectile dysfunction reported in 13% to 24%. Schrader et al investigated the nocturnal penile tumescence and rigidity in 17 patrol officers riding an average of 5.4 h/day in comparison with 5 nonbiking men. Results showed that the percentage of sleep sessions that recorded an erectile event was significantly lower in the cyclists (27.1%) than it was in noncyclists (42.8%) suggesting that prolonged bicycle riding may have negative effects on nocturnal erectile function. The compression and the stretch of the pudendal nerve near critical points like the ischiatic tuberosities and the pubic arc during pedaling seems to be the cause of both genital numbness and erectile dysfunction. The mechanical pressure leads to transient hypoxemia of the nerve and/or to a primary neuropathic process. The duration of these compressions seems to be more relevant than the amount of the pressure itself. Another possible pathophysiological mechanism of erectile dysfunction in cyclists is due to the compression of the perineal artery with a decrease of the blood flow to the penis and a consequent imbalance between the transforming growth factor beta 1 (TGF-b1) and prostaglandin E (PGE) in favor of TGF-b1 which induces collagen and connective tissue synthesis in the corpus cavernosum. Through examining this problem from a biomechanical point of view Gemery et al proposed a model of the complex saddle/perineum by means of tomography scans of 1 adult male pelvis and 3 bicycle seats. The pelvis/seats model developed by these authors showed that during cycling the most compressed point of the internal pudendal artery was immediately below the pubic symphysis. The mechanical compression of perineum tissue during tigated by means of magnetic resonance al cavernous spaces, where the penile are located. This study confirmed the www.md-journal.com | 1 is an intermediate model, and END is specifically developed for long distances and presents an anatomic curved shape. The participants’ bicycles were all equipped with a traditional most inferior aspect of the pubic symphysis to be the most compressed part. Furthermore, corpus spongiosus diameter was 148% greater than the loaded condition while right and left corpora cavernosa diameters were, respectively, 232% and 252% with respect to the loaded condition. The evolution of bicycle saddle geometries has aimed to reduce the compressive load on the corresponding soft tissues. To evaluate the reduction in such loads pressure sensor mats resulted to be the more indicated systems and thus they have been employed in previous investigations. From a physiological point of view the capacity of different saddle shapes to reduce perineal pressure was indirectly quantified measuring the penile oxygen pressure. For this aim the most indicated instrument is the oxymeter. To provide evidence-based information in developing saddle design, Potter et al investigated the influence of gender, power, hand position, and ischial tuberosities width on saddle pressure during seated stationary cycling. Only 1 previous study has investigated the level of perceived comfort using different saddle shapes. The authors found that a partial nose saddle design may result in more comfort than a standard or complete no nose 1. Surprisingly, even if within the cycling community it is well recognized the importance of padded shorts, scientific research on this topic is lacking. To the best of our knowledge, only 1 paper proposed the use of padded shorts as a preventive measure against skin chafing. On this point, an additional advice comes from the Royal Military College of Australia which stated that pants with chamois pads are the most comfortable and allow sweat absorption. Despite the paucity in the literature with regard to this topic, the beneficial effect of other padded cyclist garments such as gloves on reducing the pressure on the ulnar nerve was previously demonstrated. Therefore, the aim of this study was to analyze the effect of cyclist padded shorts in reducing pressure on the buttocks, with the ultimate goal of helping the manufacturers designing the pads. To accomplish this task, we evaluated 3 different types of pads introducing an objective evaluation of their level of comfort using biomechanical measurements, which was compared with the subjective ranking expressed by the cyclists.